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        <title>Frida - 标签 - 有价值炮灰</title>
        <link>https://evilpan.com/tags/frida/</link>
        <description>Frida - 标签 - 有价值炮灰</description>
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            <webMaster>i@pppan.net (evilpan)</webMaster><copyright>This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</copyright><lastBuildDate>Sun, 22 May 2022 10:40:00 &#43;0800</lastBuildDate><atom:link href="https://evilpan.com/tags/frida/" rel="self" type="application/rss+xml" /><item>
    <title>终端应用安全之网络流量分析</title>
    <link>https://evilpan.com/2022/05/22/network-analysis/</link>
    <pubDate>Sun, 22 May 2022 10:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2022/05/22/network-analysis/</guid>
    <description><![CDATA[<p>在日常对客户端应用进行安全审计或者漏洞挖掘的时候，或多或少都会涉及到网络协议的分析。而对于业务风控安全而言，APP 的网络请求往往也代表着终端安全防御水平的上限，因为客户端是掌控在攻击者手中的，服务端的业务逻辑才是安全的核心兜底保障。</p>
<p>本文是笔者在分析众多 Android 应用协议的过程中所尝试总结的一些经验，大部分情况下也可以适用于其他平台的终端应用，如 iOS、macOS、Windows 等，尽管各个操作系统中会存在一些特有的小技巧。</p>
<h1 id="网络流量分析" class="headerLink">
    <a href="#%e7%bd%91%e7%bb%9c%e6%b5%81%e9%87%8f%e5%88%86%e6%9e%90" class="header-mark"></a>网络流量分析</h1><p>在介绍具体的流量分析方法之前，我们需要先明确流量分析的目的。对于笔者而言，流量分析的目的通常是为了搞清楚应用某个操作背后实际的行为。比如对于 IM 聊天软件而言，需要了解发送文本消息、图片消息、多媒体消息等背后实际的请求是什么，以梳理其中潜在的攻击面；对于社交类应用，可能黑灰产最关心的是账号创建、登录以及点赞等操作背后的协议，以用于水军的构建；而对于病毒分析师，可能更关注样本与 CC 服务器之间命令协议，以尝试溯源木马背后的僵尸网络。……</p>
<p>其中木马病毒的场景相对特殊，本文更多是针对商业应用的网络流量分析。在分析流量的时候，我们显然需要能够观测到目标流量的明文。这看似是一个简单的需求，却并不容易实现。</p>
<p>首先考虑网络协议的类型，既然是商业应用，那么大部分情况下使用的也是较为通用的网络协议，即 HTTP。但由于面临运营商劫持等原因，目前以 HTTP 请求进行明文传输的仅是少数了，TLS 已经成为目前网络加密的主流。</p>
<p>其次在应用层，目标请求也有不少是经过自行加密的，可以是一个简化版的 ECDH，也可以是随机 AES 秘钥 + 内置公钥加密的方式。这对于第三方而言，并没有一个很好的方式进行通用解密，只能根据不同应用进行 case by case 的逆向分析并进行还原。</p>
<p>因此，对于应用层加密的情况姑且先不考虑，在面对常规 TLS 加密的流量时，我们最好能够有一种方法能够对其进行解密还原。在 TLS 之下并非只有 HTTP，也有部分使用了 MQTT、Websocket 等协议的请求，必要时也需要考虑在内。</p>
<p>因此，我们的应用网络流量分析目标，又可以分解成两个小目标:</p>
<ol>
<li>目标应用流量截取(捕获)；</li>
<li>目标应用流量解密(TLS 解密)；</li>
</ol>
<p>当然，实际的流量分析并不一定需要两个目标同时达成。在某些场景下，可以仅仅通过解密观察到目标的请求数据，并通过日志打印等方式展示出来。</p>
<h1 id="流量抓取" class="headerLink">
    <a href="#%e6%b5%81%e9%87%8f%e6%8a%93%e5%8f%96" class="header-mark"></a>流量抓取</h1><p>首先看应用流量截取的方案，也即通常我们所说的“抓包”。</p>
<h2 id="系统代理" class="headerLink">
    <a href="#%e7%b3%bb%e7%bb%9f%e4%bb%a3%e7%90%86" class="header-mark"></a>系统代理</h2><p>这是最为简单也是最为常用的一种抓包方案。在 Android、iOS、macOS 这些操作系统中连接 WiFi 时可以指定我们自定义的 HTTP 代理地址。如果应用使用了是系统提供的网络库或者遵循这个代理配置，那么就会将 HTTP(S) 请求通过该代理进行发送。</p>
<p>因此，这种方式有个很明显的缺点: 应用可能不按规矩来。不管是设置的系统代理，还是通过 <code>HTTP_PROXY</code> 环境变量指定代理，都只是一种<strong>约定俗成</strong>的规则而已。应用完全可以在自身代码中通过 <code>socket</code>、<code>connect</code>、<code>write</code> 三连去直接发送网络请求，这样我们的代理就无法收到任何数据。即便是对于系统提供的 HTTP 网络库，一般也会有额外的配置选项，让调用者指定或者忽略任何系统代理。</p>
<p>设置系统代理进行抓包的方法也是有优点的。这种方式配置起来比较简单，而且对应的配套工具也相对成熟，Burpsuite、Fiddle 之类的工具可以很方便的对代理到的流量进行格式化和重放分析。当然，对于非 HTTP 的其他协议支持可能就不是很完善了。</p>
<p>除了直接设置系统代理，对于桌面应用其实还有一些其他方式去对目标应用进行代理，比如使用 <code>proxychains</code> 工具去加载动态库从而重定向目标网络请求。虽然原理不同，但其实际效果比较类似，因此也统一归类为系统代理方法。</p>
<h2 id="路由抓包" class="headerLink">
    <a href="#%e8%b7%af%e7%94%b1%e6%8a%93%e5%8c%85" class="header-mark"></a>路由抓包</h2><p>既然系统代理模式抓包容易被应用绕过导致流量缺失，那么一个直观的想法就是回归流量分析的本身，直接在网络层进行抓包。其中比较常用的方式就是路由抓包，即在网关层进行抓包。</p>
<p>具体实现也不难，大家应该都知道在近源渗透中的 evilTwin AP, 即假热点的攻击方法。攻击者通过可以完全控制的机器创建一个假热点，待目标连入后进行网络劫持，从而获取敏感信息，或者替换关键流量实现代码执行。从这个角度上看，该方法也可以看做是一种 “网络临侦”。</p>
<p>对于我们的抓包方案来说，可以构建一个真热点，一般使用开源的 <code>hostapd</code> 可以实现；而热点网络所需要的 DHCP 服务器或者 DNS 服务器可以通过 <code>dnsmasq</code> 去实现。</p>
<p>路由抓包方案通常与透明代理进行结合使用，以实现 HTTP 请求分析、劫持与重放的功能。<strong>透明代理</strong>对于客户端而言是一个真实的 HTTP 服务器，通常通过 DNS 劫持或者路由劫持去实现。Nginx 中一个重要的功能就是透明代理，在同一个公网地址进行监听，并通过不同的域名分发到实际的后端服务器中。</p>
<p>前文提到的许多 HTTP 代理工具也支持透明代理，比如 BurpSuite 就支持 <a href="https://portswigger.net/burp/documentation/desktop/tools/proxy/options/invisible" target="_blank" rel="noopener noreferrer">invisible proxy</a>，mitmproxy 中称为 <a href="https://docs.mitmproxy.org/stable/howto-transparent/" target="_blank" rel="noopener noreferrer">Transparent proxy</a> ，通过 <code>-m transparent</code> 指定。</p>
<p>路由抓包和系统代理相比具有很多优点，比如可以保证抓到所有的 HTTP/HTTPS 流量，并且对于目标应用透明。这里有个潜在的好处，由于对被抓包目标透明，因此路由抓包可以用于一些 IoT 设备的流量分析，比如车机设备、智能家居等等。</p>
<p>缺点也很明显，即路由抓包需要额外的自定义路由设备。如果是运行在 PC 端且驱动支持完善的话还好，可以在个人电脑上作为临时热点；如果电脑(系统)不支持可能还需要在虚拟机里跑个 Ubuntu 去运行，或者使用额外的硬件如树莓派去执行代码，相比于前面的方法复杂度上升不少。另外使用路由抓包方法捕获到的流量是整个系统的流量，而不仅限于目标应用，因此我们还需要对这些流量进行额外的过滤。</p>
<h2 id="虚拟网卡" class="headerLink">
    <a href="#%e8%99%9a%e6%8b%9f%e7%bd%91%e5%8d%a1" class="header-mark"></a>虚拟网卡</h2><p>路由抓包方案的目标是为了完全捕捉到目标应用流量，确保没有遗漏，另外还可以使用透明代理去实现 HTTP 请求的解析。这种方法的本质是在目标应用的路由中间节点进行网络劫持，其实要实现这个目标可以直接在应用端实现。</p>
<p>实现原理就是在本地运行一个<strong>虚拟专用网络</strong>，构建一个虚拟网卡设备，并将路由规则修改为优先通过我们虚拟的网卡进行请求。比如，Android 上可以通过实现 VPNService 去构建自己的 VPN 服务，<code>ProxyDroid</code> 就是其中的一个实现；在 macOS 或者 iOS 中可以使用 Surge 等工具去实现类似的功能。</p>
<p>将路由抓包在客户端上实现的一大好处是可以通过系统信息将网络请求与实际的进程相关联，同时省去了对额外设备的依赖；缺点则是比较依赖代理工具的工程实现，据我所知实现效果较好的工具其价格也不菲。当然这种抓包方式笔者使用得不多，如果有其他好的类似工具也欢迎留言分享一下。</p>
<h2 id="libpcap" class="headerLink">
    <a href="#libpcap" class="header-mark"></a>libpcap</h2><p>那位说了，既然都在端上抓包了，为什么不更直接一点，使用 tcpdump 或者 Wireshark 这类工具进行抓包？别急，这正是这一节要介绍的最后一种抓包方法。tcpdump 这类工具本质上是基于 libpcap 的，相信大家都比较熟悉了。</p>
<p>其实在前文中路由(网关)抓包和虚拟网卡抓包的方式中，都可以使用 tcpdump 进行抓包，前者需要指定网卡为热点网卡(AP)，后者指定为虚拟网卡(TUN)即可。这样抓包出来的结果是一个 <code>pcap</code> 文件，一般直接丢到 Wireshark 里面去进行分析。与前面的方法相比，这种方法对于 HTTP 的可视化解析可能相对简陋，但是对于协议类型的支持却非常广泛，基本上你能叫出名字的标准协议都可以进行解析。</p>
<p>因此，pcap 分析往往作为一种兜底的网络分析方式。而之所以很多情况下使用前面的方法而不是此法，是因为商业应用的大部分是 HTTP/HTTPS 流量，前面那些代理工具可以帮我们解决以很大部分的解密和可视化工作，即与下一节中提到的 TLS 解密方法相互权衡后所采用的决策。</p>
<p>这里分享一个 libpcap 的抓包技巧。笔者平时分析 Android 应用比较多，而在抓包时会发现有很多不相关的后台流量扰乱视听。实际上可以在 UID 为维度进行抓包，这样就可以只抓取对应应用的流量了。</p>
<p>这个功能称为 <a href="https://wiki.wireshark.org/CaptureSetup/NFLOG" target="_blank" rel="noopener noreferrer">NFLOG</a>，即 NetFilter Log。libpcap 在 1.2.1 版本之后支持抓取 nflog 的数据，而 <code>iptables</code> 又支持支持 uid 的过滤，二者相结合，比如要抓取 uid 为 1000 的应用数据，可以这样实现:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-1" 
    class="
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      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ iptables -A OUTPUT -m owner --uid-owner <span class="m">1000</span> -j CONNMARK --set-mark <span class="m">1</span>
</span></span><span class="line"><span class="cl">$ iptables -A INPUT -m connmark --mark <span class="m">1</span> -j NFLOG --nflog-group <span class="m">30</span> 
</span></span><span class="line"><span class="cl">$ iptables -A OUTPUT -m connmark --mark <span class="m">1</span> -j NFLOG --nflog-group <span class="m">30</span> 
</span></span><span class="line"><span class="cl">$ tcpdump -i nflog:30 -w uid-1000.pcap</span></span></code></pre>
</div>
<p>由于 uid 信息只关联在发送包上，因此只能添加到 <code>OUTPUT</code> 链上，但可以通过 <code>connmark</code> 去关联返回的数据，这样即可实现单个指定应用(uid)的的抓包了。</p>
<h1 id="流量解密" class="headerLink">
    <a href="#%e6%b5%81%e9%87%8f%e8%a7%a3%e5%af%86" class="header-mark"></a>流量解密</h1><p>上节中介绍了流量抓取的一些方案，对于常规 HTTP 流量而言没有太大争议，但是对于当今日趋普遍的 HTTPS 却有一些悬而未决的问题。如果我们抓到的所有 HTTPS 流量都是通过 TLS 进行加密的，那对于分析而言就几乎毫无价值了。</p>
<p>因此，为了能够对目标应用进行网络分析，应用层的私有加密姑且不论，至少要解决标准的 TLS 的解密问题。解密是为了中间人攻击，获取明文流量，那么就需要知道 TLS 中常规的中间人防御方案，一般来说，有下面几种:</p>
<ol>
<li>客户端验证服务端的证书链可信，基本操作；</li>
<li>服务端验证客户端的证书可信(Certificate Request)，又称为双向证书绑定；</li>
<li>客户端验证服务端的证书 HASH 是否在白名单中，即 SSL Pinning；</li>
<li>……</li>
</ol>
<p>在介绍后文的具体解密方案中也会围绕这几点去进行分析。</p>
<h2 id="根证书" class="headerLink">
    <a href="#%e6%a0%b9%e8%af%81%e4%b9%a6" class="header-mark"></a>根证书</h2><p>添加自定义的根证书应该是 HTTPS 流量分析的标准答案了。前文中提到的 Burpsuite、mitmproxy 等工具的文档中肯定都有介绍如何添加自定义根证书，根证书的存放对于不同的操作系统甚至不同的应用都有不同路径。比如在 Android 中，根证书存放在 <code>/system/etc/security/cacerts</code> 目录之下；在 iOS/macOS 中，根证书存放在 <code>Keychain</code> 中；对于 <code>Firefox</code> 浏览器，其应用中打包了证书链，不使用系统的证书。……</p>
<p>至于如何添加根证书，上过学的话应该都能在搜索引擎中找到方法，这里就不再啰嗦了。虽然添加自定义根证书可以让我们很方便地使用代理工具进行 HTTPS 流量分析，但其实际上只解决了第一个问题，因此对于某些做了额外校验的应用而言 TLS 握手还是无法成功的。</p>
<p>如果目标应用服务器在 TLS 握手中校验了客户端证书，那么我们还需要在代理工具中添加对应私钥才能顺利完成握手。该证书一般以 <code>p12</code> 格式存放，包含了客户端的证书及其私钥，通常还有一个额外的密码。通过逆向分析目标应用的的加载代码往往不难发现客户端证书的踪迹，甚至有时可以直接在资源文件中找到。</p>
<p>如果目标应用使用了 SSL Pinning 加固，那么通常是将服务器的证书 HASH 保存在代码中，并在握手<strong>之后</strong>进行额外校验。由于相关数据(证书HASH)和逻辑都在代码中，因此这种情况下往往只能通过侵入式的方式去绕过 Pinning 校验，比如 Patch 代码或者使用 hook 等方法实现。由于这是一个较为常见的功能，因此网上有很多相关脚本可以实现常规的 SSL Pinning bypass，但需要注意的是这并不意味着可以 100% 绕过，对于一些特殊实现仍然需要进行特殊分析。</p>
<h2 id="ssl-keylog" class="headerLink">
    <a href="#ssl-keylog" class="header-mark"></a>SSL keylog</h2><p>除了在端侧添加自定义根证书，还有一种方式可以解密 SSL/TLS 的流量，即在握手过程中想办法获取到 TLS 会话的 <code>Master Key</code>，根据协商的加密套件，就可以对整个 TLS stream 进行解密。关于 TLS 握手的原理介绍，可以参考笔者上一篇文章 —— <a href="https://evilpan.com/2022/05/15/tls-basics/" target="_blank" rel="noopener noreferrer">深入浅出 SSL/TLS 协议</a>。</p>
<p>知名的抓包和网络协议分析工具 <code>Wireshark</code> 就支持通过添加 <code>keylog</code> 文件去辅助 TLS 流量的解密。这里的 keylog 就是 <a href="https://wiki.wireshark.org/TLS" target="_blank" rel="noopener noreferrer">TLS 会话秘钥</a>，文件格式为 <a href="https://firefox-source-docs.mozilla.org/security/nss/legacy/key_log_format/index.html" target="_blank" rel="noopener noreferrer">NSS Key Log Format</a>。对于不同版本的 TLS 内容略有不同，在 TLS 1.2 中只需要一个会话的 MasterKey，使用 <code>CLIENT_RANDOM</code> 去区分不同会话；而在 TLS 1.3 中每个会话包含 5 个秘钥，分别用于解密握手、数据阶段的不同数据。</p>
<p>那么，这个 keylog 文件我们应该如何获取呢？对于大部分 SSL 库而言，比如 OpenSSL、BoringSSL、libreSSL 等，都可以通过 <a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_keylog_callback.html" target="_blank" rel="noopener noreferrer">SSL_CTX_set_keylog_callback</a> 这个 API 去设置获取的回调，令 SSL 库在握手成功后调用对应的回调函数从而获取 keylog。因此我们就需要通过静态 patch 或者动态 hook 的方式去为 TLS 添加该回调。</p>
<p>这看似很简单，但实际操作起来会遇到一些问题。比如，很多大型商业应用都封装了自己的 SSL 库，甚至同一个应用中不同组件中又间接包含了有多个 SSL 库，为了每一个 TLS 会话都能成功解密，需要确保每个 SSL 库都要被正确 patch 或者 hook；</p>
<p>其次，对于某些组件而言，实际是通过静态编译的方式引入 SSL 库，比如 <code>webview</code>、<code>libflutter</code>、<code>libffmpeg</code> 等。在去除掉符号后，我们可能需要通过一些方法去搜索定位所需的符号地址。这个任务的难度可大可小，简单的可以通过 yara、Bindiff 去进行定位，复杂的话也可以通过一些深度学习算法去进行相似度分析，比如科恩的 <code>BinaryAI</code> 或者阿里云的 <code>Finger</code> 等。感兴趣的也可以去进一步阅读相关的综述文章:</p>
<blockquote>
  <p><a href="https://www.eurecom.fr/publication/6847/download/sec-publi-6847.pdf" target="_blank" rel="noopener noreferrer">USENIX Security 2022 - How Machine Learning Is Solving the Binary Function Similarity Problem</a></p>
</blockquote><p>另外还有一个问题，<code>SSL_CTX_set_keylog_callback</code> 这个 API 并不是最初就存在于 SSL 库中的。以 openssl 为例，keylog 文件的支持实际上是在 commit <a href="https://github.com/openssl/openssl/commit/4bf73e9f86804cfe98b03accfc2dd7cb98e018d6" target="_blank" rel="noopener noreferrer">4bf73e</a> 中才被引入。因此，如果遇到了某些应用中依赖于旧版本的 SSL 库，那么可能就不支持 keylog。我们要想强行支持就要进行二进制级别的 cherry-pick，这个工作量还是挺大的。</p>
<p>虽然有这些那些难点，但这种解密方法的一大优点是可以一次性解决本节开头所提及的三个问题，即服务端证书校验、客户端证书校验和 SSL Pinning。因为该方法并没有对流量进行网络层面的中间人，而是在应用的运行过程中泄露会话秘钥，因此不会影响上层的证书校验。</p>
<h2 id="ssl-readwrite" class="headerLink">
    <a href="#ssl-readwrite" class="header-mark"></a>SSL read/write</h2><p>既然设置 keylog 如此麻烦，为什么不找一些相对简单且通用的 API 去进行解密呢？一个直接的思路就是通过挂钩 <a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_read.html" target="_blank" rel="noopener noreferrer">SSL_read</a>、SSL_write 来获取 SSL 读写的明文数据。基于这个思路目前网上有许多工程化的实现，比如 <a href="https://github.com/ehids/ecapture" target="_blank" rel="noopener noreferrer">eCapture</a> 是基于 <code>eBPF/uprobes</code> 的 TLS 抓包方案；<a href="https://github.com/r0ysue/r0capture" target="_blank" rel="noopener noreferrer">r0capture</a> 则是基于 <code>frida</code> 注入的 TLS 抓包方案。</p>
<p>使用该方法进行解密的一大优点，或者说特点，是这种方式可以在解密的同时直接输出明文信息，因此可以完全略过<strong>流量抓取</strong>这一步。虽然许多开源工具是将结果保存为 pcap 文件进行进一步分析的，但实际上也可以直接在标准输出或者日志文件中打印出来进行分析。</p>
<p>由于这些抓包工具本质上都是在获取 SSL read/write 明文的基础上再以 pcap 格式进行转储，因此同样会面临 keylog 方案所面临的问题，即依赖 SSL 库的符号。但不同的是其所依赖的是较为通用的符号，因此不太会受到 SSL 库版本的限制。唯一需要考虑的难题是如何解析无符号的 SSL 库中相关函数的偏移地址，这在上节中有些简单介绍，展开的话又是另一篇论文了。</p>
<h1 id="小结" class="headerLink">
    <a href="#%e5%b0%8f%e7%bb%93" class="header-mark"></a>小结</h1><p>上述介绍的每一种流量抓取方法都可以和任意一种流量解密方法相结合，组成一种网络流量分析方案。实践上使用较多的是下面几种组合:</p>
<ul>
<li>系统 HTTP 代理 + 根证书</li>
<li>路由抓包/透明代理 + 根证书</li>
<li>tcpdump + keylog</li>
<li>SSL_read/SSL_write hook</li>
</ul>
<p>每种方案都有其优点和缺点:</p>

<div class="table-wrapper">
  <table>
    <thead>
        <tr>
            <th style="text-align: ">抓包方案</th>
            <th style="text-align: ">优点</th>
            <th style="text-align: ">缺点</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td style="text-align: ">系统代理</td>
            <td style="text-align: ">配置简单，工具成熟</td>
            <td style="text-align: ">可被忽略，流量不全，证书问题</td>
        </tr>
        <tr>
            <td style="text-align: ">路由抓包</td>
            <td style="text-align: ">流量完整，应用透明</td>
            <td style="text-align: ">配置复杂，协议受限，证书问题</td>
        </tr>
        <tr>
            <td style="text-align: ">tcpdump + keylog</td>
            <td style="text-align: ">流量完整，无需证书<br>协议丰富，应用过滤</td>
            <td style="text-align: ">TLS 解密需要 hook 应用<br>且依赖于 SSL 库的版本和符号</td>
        </tr>
        <tr>
            <td style="text-align: ">SSL read/write</td>
            <td style="text-align: ">劫持简单，无需证书</td>
            <td style="text-align: ">需要(某些)符号，依赖 hook，流量不全</td>
        </tr>
    </tbody>
  </table>
</div>
<p>那么实际安全分析中要如何选择呢？正如那句老话所说: <strong>网络安全没有银弹</strong>，实际情况也无法一概而论，通常是根据具体的目标去进行分析。</p>
<p>例如，对于操作系统比较封闭的 IoT 设备，通过路由抓包是唯一选择；对于移动应用或者桌面应用而言，可以先尝试传统的系统代理方式，添加对应根证书，如果不能抓到包，可以通过流量分析可能的问题:</p>
<ul>
<li>流量日志中服务端有 Certificate Request 则表示进行了客户端证书校验；</li>
<li>流量日志中握手成功但很快断开，则客户端中可能使用了 SSL Pinning 加固；</li>
<li>流量日志中客户端握手失败，Alert 提示证书不可信，则说明客户端使用了自定义的  keystore 而不是系统的根证书；</li>
<li>……</li>
</ul>
<p>此时如果发现客户端使用了多种方法防止 HTTP 代理进行中间人抓包，那么就可以尝试使用 keylog 或者 SSL read/write hook 的方式进行分析。总而言之，流量层的分析可以确保数据的完备性，即应用发送的请求都能够确保抓到；而 HTTP 代理和部分解密方法对于 Web 流量则更具针对性，在不同的场景中可以对不同分析方案进行灵活切换。</p>
<h1 id="参考链接" class="headerLink">
    <a href="#%e5%8f%82%e8%80%83%e9%93%be%e6%8e%a5" class="header-mark"></a>参考链接</h1><ul>
<li><a href="https://evilpan.com/2022/05/15/tls-basics/" target="_blank" rel="noopener noreferrer">深入浅出 SSL/TLS 协议</a></li>
<li><a href="https://blog.nviso.eu/2019/08/13/intercepting-traffic-from-android-flutter-applications/" target="_blank" rel="noopener noreferrer">Intercepting traffic from Android Flutter applications</a></li>
<li><a href="https://mabin004.github.io/2020/07/24/%E8%87%AA%E5%8A%A8%E5%AE%9A%E4%BD%8Dwebview%E4%B8%AD%E7%9A%84SLL-read%E5%92%8CSSL-write/" target="_blank" rel="noopener noreferrer">自动定位webview中的SLL_read和SSL_write</a></li>
</ul>
<hr>
<blockquote>
  <p><strong>版权声明</strong>: 自由转载-非商用-非衍生-保持署名 (<a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noopener noreferrer">CC 4.0 BY-SA</a>)<br>
<strong>原文地址</strong>: <a href="https://evilpan.com/2022/05/22/network-analysis/" target="_blank" rel="noopener noreferrer">https://evilpan.com/2022/05/22/network-analysis/</a><br>
<strong>微信订阅</strong>: <strong>『<a href="http://t.evilpan.com/qrcode.jpg" target="_blank" rel="noopener noreferrer">有价值炮灰</a>』</strong><br>
&ndash; <em>TO BE CONTINUED</em>.</p>
</blockquote><hr>]]></description>
</item><item>
    <title>Frida Internal - Part 3: Java Bridge 与 ART hook</title>
    <link>https://evilpan.com/2022/04/17/frida-java/</link>
    <pubDate>Sun, 17 Apr 2022 12:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2022/04/17/frida-java/</guid>
    <description><![CDATA[<p>前面的文章中介绍了 frida 的基础组件 <code>frida-core</code>，用于实现进程注入、通信和管理等功能。加上 frida-gum 和 gum-js 的核心能力，我们已经可以很方便地使用 JavaScript 脚本来进行代码劫持、动态跟踪等进程分析操作。</p>
<p>不过 frida 并不满足于此，而是又实现了针对高级语言的支持，比如 <code>Java</code>、<code>Objective-C</code>、<code>Swift</code> 等。这些额外支持实际上是在 <code>gum-js</code> 的基础上针对对应高级语言的 Runtime 进行 hack 而实现的，统一称为对应语言的 bridge。例如，针对 Java 语言的封装称为 <code>frida-java-bridge</code>，不仅实现了 Oracle JVM 的封装、还支持 Android 中的 Dalvik 虚拟机和 ART 虚拟机。本文就以 ART 为例来看看 frida 中的具体实现。</p>
<p>传送门:</p>
<ul>
<li><a href="https://evilpan.com/2022/04/05/frida-internal/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 1: 架构、Gum 与 V8</a></li>
<li><a href="https://evilpan.com/2022/04/09/frida-core/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 2: frida-core</a></li>
<li><a href="https://evilpan.com/2022/04/17/frida-java/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 3: frida-java-bridge 与 ART hook (本文)</a></li>
</ul>
<h1 id="java-bridge" class="headerLink">
    <a href="#java-bridge" class="header-mark"></a>Java Bridge</h1><p><a href="https://github.com/frida/frida-java-bridge" target="_blank" rel="noopener noreferrer">frida-java-bridge</a> 就是我们在编写 frida js 脚本时使用的 <code>Java.use</code> 等接口实现。Java 接口是 Android Runtime 的封装，实现在 <code>index.js</code> 的 <code>class Runtime</code> 中。比如 <code>Java.perform</code> 就对应了 <code>Runtime.perform</code> 函数。 在 Runtime 的构造函数中分别初始化了 api、vm 和 classFactory 属性等属性:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
    tw-flex-row
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          <p class="tw-select-none !tw-my-1">js</p>
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          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-38" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">_tryInitialize</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">this</span><span class="p">.</span><span class="nx">api</span> <span class="o">=</span> <span class="nx">getApi</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">vm</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">VM</span><span class="p">(</span><span class="nx">api</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">ClassFactory</span><span class="p">.</span><span class="nx">_initialize</span><span class="p">(</span><span class="nx">vm</span><span class="p">,</span> <span class="nx">api</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">classFactory</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ClassFactory</span><span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>下面分别对其进行介绍。</p>
<h2 id="native-api" class="headerLink">
    <a href="#native-api" class="header-mark"></a>Native API</h2><p>API 是从对应 Java 虚拟机的动态库中所抽象出来的一套统一接口，用以实现对运行时、垃圾回收、堆栈管理等底层操作，是实现上层方法劫持和替换的基础设施。</p>
<p>在 <code>lib/api.js</code> 中指定了 API 的类型，如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-39" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">let</span> <span class="p">{</span> <span class="nx">getApi</span><span class="p">,</span> <span class="nx">getAndroidVersion</span> <span class="p">}</span> <span class="o">=</span> <span class="nx">require</span><span class="p">(</span><span class="s1">&#39;./android&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">getAndroidVersion</span><span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="nx">e</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">getApi</span> <span class="o">=</span> <span class="nx">require</span><span class="p">(</span><span class="s1">&#39;./jvm&#39;</span><span class="p">).</span><span class="nx">getApi</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="nx">module</span><span class="p">.</span><span class="nx">exports</span> <span class="o">=</span> <span class="nx">getApi</span><span class="p">;</span></span></span></code></pre>
</div>
<p>通过尝试调用 libc 的 <code>__system_property_get</code> 函数获取属性，如果成功表示当前进程为 Android 环境，即 Java 实现为 Dalvik 或者 ART 虚拟机；如果失败则认为是 Oracle 的 JVM 虚拟机实现。java-bridge 的实现是基于 inline-hook (gum-js) 对目标 Java 虚拟机中的符号进行解析、调用、替换从而实现 Java Hook 的功能，其支持的三种虚拟机及其对应动态库分别是:</p>
<ul>
<li>Dalvik: libdvm.so</li>
<li>ART: libart.so</li>
<li>JVM: jvm.(dll|dylib|so)</li>
</ul>
<p>由于三种实现大同小异，因此我们只需要关注其中一种。因为笔者对于 Android 较为感兴趣，故而重点关注 ART 下的实现。在 <code>lib/android.js</code> 中 <code>_getApi</code> 同时处理了 Dalvik 和 ART 虚拟机的情况，区分这二者的方法是判断当前进程中加载的模块是 libdvm.so 还是 libart.so。</p>
<h3 id="查找符号" class="headerLink">
    <a href="#%e6%9f%a5%e6%89%be%e7%ac%a6%e5%8f%b7" class="header-mark"></a>查找符号</h3><p>在两种情况下都需要先获取对应动态库中的一些符号地址，对于 ART 而言，主要需要下面函数:</p>
<ul>
<li>JNI_GetCreatedJavaVMs</li>
<li>art::JavaVMExt::AddGlobalRef</li>
<li>art::IndirectReferenceTable::Add</li>
<li>art::JavaVMExt::DecodeGlobal</li>
<li>art::ThreadList::SuspendAll</li>
<li>art::ThreadList::ResumeAll</li>
<li>art::ClassLinker::VisitClasses</li>
<li>art::ClassLinker::VisitClassLoaders</li>
<li>art::gc::Heap::VisitObjects</li>
<li>art::gc::Heap::GetInstances</li>
<li>art::StackVisitor::StackVisitor</li>
<li>art::StackVisitor::WalkStack</li>
<li>art::StackVisitor::GetMethod</li>
<li>art::StackVisitor::DescribeLocation</li>
<li>art::StackVisitor::GetCurrentQuickFrameInfo</li>
<li>art::Thread::GetLongJumpContext</li>
<li>art::mirror::Class::GetDescriptor</li>
<li>art::ArtMethod::PrettyMethod</li>
<li>art::ArtMethod::PrettyMethodNullSafe</li>
<li>art::Thread::CurrentFromGdb</li>
<li>art::mirror::Object::Clone</li>
<li>art::Dbg::SetJdwpAllowed</li>
<li>art::Dbg::ConfigureJdwp</li>
<li>art::InternalDebuggerControlCallback::StartDebugger</li>
<li>art::Dbg::StartJdwp</li>
<li>art::Dbg::GoActive</li>
<li>art::Dbg::RequestDeoptimization</li>
<li>art::Dbg::ManageDeoptimization</li>
<li>art::Instrumentation::EnableDeoptimization</li>
<li>art::Instrumentation::DeoptimizeEverything</li>
<li>art::Runtime::DeoptimizeBootImage</li>
<li>art::Instrumentation::Deoptimize</li>
<li>art::jni::JniIdManager::DecodeMethodId</li>
<li>art::interpreter::GetNterpEntryPoint</li>
<li>art::Monitor::TranslateLocation</li>
</ul>
<p>以及两个用于判断调试器状态的变量:</p>
<ul>
<li>art::Dbg::gRegistry - 判断 JDWP 是否启动</li>
<li>art::Dbg::gDebuggerActive - 判断是否正在调试</li>
</ul>
<p>值得一提的是，这两个变量也可以用在安全 SDK 中作为一种隐秘的反调试手法。</p>
<p>上面的函数通过在模块中的符号中查找到对应地址后 (如 <code>Module.enumerateExports(&quot;libart.so&quot;)</code>)，便将其转换为 <code>NativeFunction</code> 类然后保存到 temporaryApi 字典中留作备用。</p>
<h3 id="查找偏移" class="headerLink">
    <a href="#%e6%9f%a5%e6%89%be%e5%81%8f%e7%a7%bb" class="header-mark"></a>查找偏移</h3><p>在找到上述的函数和变量地址后，就可以通过这些 Native 函数获取需要的信息，首先第一步是获取当前进程中所有创建的 Java 虚拟机。这里使用的是 <strong>JavaScript</strong> 代码去调用，乍看起来有点别扭，但这是做 Native 调用的常规操作:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-40" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">vms</span> <span class="o">=</span> <span class="nx">Memory</span><span class="p">.</span><span class="nx">alloc</span><span class="p">(</span><span class="nx">pointerSize</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">vmCount</span> <span class="o">=</span> <span class="nx">Memory</span><span class="p">.</span><span class="nx">alloc</span><span class="p">(</span><span class="nx">jsizeSize</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="nx">temporaryApi</span><span class="p">.</span><span class="nx">JNI_GetCreatedJavaVMs</span><span class="p">(</span><span class="nx">vms</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="nx">vmCount</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="k">if</span> <span class="p">(</span><span class="nx">vmCount</span><span class="p">.</span><span class="nx">readInt</span><span class="p">()</span> <span class="o">===</span> <span class="mi">0</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="nx">temporaryApi</span><span class="p">.</span><span class="nx">vm</span> <span class="o">=</span> <span class="nx">vms</span><span class="p">.</span><span class="nx">readPointer</span><span class="p">();</span></span></span></code></pre>
</div>
<p>该函数原型为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-41" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">jint</span> <span class="nf">JNI_GetCreatedJavaVMs</span><span class="p">(</span><span class="n">JavaVM</span> <span class="o">**</span><span class="n">vmBuf</span><span class="p">,</span> <span class="n">jsize</span> <span class="n">bufLen</span><span class="p">,</span> <span class="n">jsize</span> <span class="o">*</span><span class="n">nVMs</span><span class="p">);</span></span></span></code></pre>
</div>
<p>虽然参数说可以返回多个 VM，但在单个进程中是不支持创建多个 Java 虚拟机的，因此这里也只用获取一个 VM 即可。获取到的 Java 虚拟机，(即 <code>JavaVM *</code> 地址) 保存在 temporaryApi.vm 变量中，这是我们一系列后续操作的基础。</p>
<p>通过获得的 JavaVM 指针，我们可以获取一系列重要数据结构的地址，比如:</p>
<ul>
<li>art::Runtime</li>
<li>art::Instrumentation</li>
<li>art::Heap</li>
<li>art::ThreadList</li>
<li>art::ClassLinker</li>
<li>各个 trampoline 的地址</li>
<li>&hellip;</li>
</ul>
<p>其中的一些是通过结构体的固定偏移来获得，比如 art::Runtime 就在 JavaVM 结构的第二个位置:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-42" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">struct</span> <span class="nc">_JavaVM</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="k">struct</span> <span class="nc">JNIInvokeInterface</span><span class="o">*</span> <span class="n">functions</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">class</span> <span class="nc">JavaVMExt</span> <span class="o">:</span> <span class="k">public</span> <span class="n">JavaVM</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="k">public</span><span class="o">:</span>
</span></span><span class="line"><span class="cl"><span class="c1">// 一些函数 ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">Runtime</span><span class="o">*</span> <span class="k">const</span> <span class="n">runtime_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>用 gdb 也可以进行验证:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">gdb</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-43" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code class="language-gdb" data-lang="gdb">(gdb) ptype /o JavaVM
type = struct _JavaVM {
/*    0      |     8 */    const struct JNIInvokeInterface *functions;

                           /* total size (bytes):    8 */
                         }

(gdb) ptype /o art::JavaVMExt
/* offset    |  size */  type = class art::JavaVMExt : public JavaVM {
                         private:
/*    8      |     8 */    class art::Runtime * const runtime_;
...</code></pre></code></pre>
</div>
<p>但是对于一些复杂的数据结构就没有那么简单了，比如在 <code>art::Runtime</code> 结构体中查找 heap、threadList、classLinker 等属性的时候，就需要先搜索到特定的属性位置，然后通过不同版本的相对偏移去定位其他属性:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-44" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">class</span> <span class="nc">Runtime</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">gc</span><span class="o">::</span><span class="n">Heap</span><span class="o">*</span> <span class="n">heap_</span><span class="p">;</span>                <span class="c1">// &lt;-- we need to find this
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">ArenaPool</span><span class="o">&gt;</span> <span class="n">jit_arena_pool_</span><span class="p">;</span>    <span class="c1">//  &lt;----- API level &gt;= 24
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">ArenaPool</span><span class="o">&gt;</span> <span class="n">arena_pool_</span><span class="p">;</span>        <span class="c1">//      __
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">ArenaPool</span><span class="o">&gt;</span> <span class="n">low_4gb_arena_pool_</span><span class="p">;</span><span class="c1">//  &lt;--|__ API level &gt;= 23
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">LinearAlloc</span><span class="o">&gt;</span> <span class="n">linear_alloc_</span><span class="p">;</span>    <span class="c1">//      \_
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">size_t</span> <span class="n">max_spins_before_thin_lock_inflation_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="n">MonitorList</span><span class="o">*</span> <span class="n">monitor_list_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="n">MonitorPool</span><span class="o">*</span> <span class="n">monitor_pool_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="n">ThreadList</span><span class="o">*</span> <span class="n">thread_list_</span><span class="p">;</span>        <span class="c1">// &lt;--- and these
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">InternTable</span><span class="o">*</span> <span class="n">intern_table_</span><span class="p">;</span>      <span class="c1">// &lt;--/
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">ClassLinker</span><span class="o">*</span> <span class="n">class_linker_</span><span class="p">;</span>      <span class="c1">// &lt;-/
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">SignalCatcher</span><span class="o">*</span> <span class="n">signal_catcher_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">jni</span><span class="o">::</span><span class="n">JniIdManager</span><span class="o">&gt;</span> <span class="n">jni_id_manager_</span><span class="p">;</span> <span class="c1">// &lt;- API level &gt;= 30 or Android R Developer Preview
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="kt">bool</span> <span class="n">use_tombstoned_traces_</span><span class="p">;</span>     <span class="c1">// &lt;-------------------- API level 27/28
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">stack_trace_file_</span><span class="p">;</span>   <span class="c1">// &lt;-------------------- API level &lt;= 28
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">JavaVMExt</span><span class="o">*</span> <span class="n">java_vm_</span><span class="p">;</span>             <span class="c1">// &lt;-- so we find this then calculate our way backwards
</span></span></span><span class="line"><span class="cl"><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>由于 JavaVM 的地址我们已知, 故而可以在 Runtime 的起始地址处开始一直往前搜索，发现匹配后就可以确定 <code>java_vm_</code> 属性的位置，进而可以根据相对偏移往前找到 <strong>InternTable</strong>、<strong>ClassLinker</strong>、<strong>ThreadList</strong>、<strong>gc::Heap</strong> 等属性地址。之所以这样查找是因为 art::Runtime 这个数据结构相当复杂，总大小有 2000 字节以上，搜索 <code>java_vm_</code> 的时候也做了一些优化，从第 50 个指针大小位置处开始搜索，以加快搜索速度。</p>
<p>上面这些偏移都还算好找，但是在寻找 <strong>Instrumentation</strong> 偏移的时候就需要一些额外的技巧，当前 frida 使用的方法是先找到 <strong>libart.so</strong> 的 <code>MterpHandleException</code> 函数地址，由于该函数中会使用到 <code>Runtime-&gt;instrumentation</code> 的数据，因此逐条解析汇编指令即可定位到对应偏移。</p>
<p>该函数定义在 mterp.cc 中，代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
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    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-45" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">extern</span> <span class="s">&#34;C&#34;</span> <span class="n">size_t</span> <span class="n">MterpHandleException</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="n">ShadowFrame</span><span class="o">*</span> <span class="n">shadow_frame</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">REQUIRES_SHARED</span><span class="p">(</span><span class="n">Locks</span><span class="o">::</span><span class="n">mutator_lock_</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="n">DCHECK</span><span class="p">(</span><span class="n">self</span><span class="o">-&gt;</span><span class="n">IsExceptionPending</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="n">instrumentation</span><span class="o">::</span><span class="n">Instrumentation</span><span class="o">*</span> <span class="k">const</span> <span class="n">instrumentation</span> <span class="o">=</span>
</span></span><span class="line"><span class="cl">      <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetInstrumentation</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nf">MoveToExceptionHandler</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="o">*</span><span class="n">shadow_frame</span><span class="p">,</span> <span class="n">instrumentation</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>虽然道理很简单，但实际操作时候需要区分不同架构的指令解析方法，frida 中支持以下几种架构:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
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          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-46" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">instrumentationOffsetParsers</span> <span class="o">=</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">ia32</span><span class="o">:</span> <span class="nx">parsex86InstrumentationOffset</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">x64</span><span class="o">:</span> <span class="nx">parsex86InstrumentationOffset</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">arm</span><span class="o">:</span> <span class="nx">parseArmInstrumentationOffset</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">arm64</span><span class="o">:</span> <span class="nx">parseArm64InstrumentationOffset</span>
</span></span><span class="line"><span class="cl"><span class="p">};</span></span></span></code></pre>
</div>
<p>以 <strong>arm64</strong> 为例，观察该函数，可以通过寻找 <code>add</code> 指令来定位偏移，因为 <code>GetInstrumentation</code> 等函数实际上都被 inline 优化成了直接指令，如下所示，实际偏移即为 <code>0x2b8</code>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-47" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>(gdb) disassemble MterpHandleException
Dump of assembler code for function MterpHandleException(art::Thread*, art::ShadowFrame*):
   0x00000000007551ac &lt;+0&gt;:     stp     x29, x30, [sp, #-16]!
   0x00000000007551b0 &lt;+4&gt;:     mov     x29, sp
   0x00000000007551b4 &lt;+8&gt;:     adrp    x8, 0xa17000 &lt;_ZN3art2gc9allocator8RosAlloc27dedicated_full_run_storage_E+3464&gt;
   0x00000000007551b8 &lt;+12&gt;:    ldr     x8, [x8, #3280]
   0x00000000007551bc &lt;+16&gt;:    add     x2, x8, #0x2b8 // &lt;-- 这里即为所求偏移！
   0x00000000007551c0 &lt;+20&gt;:    bl      0x3e1170 &lt;art::interpreter::MoveToExceptionHandler(art::Thread*, art::ShadowFrame&amp;, art::instrumentation::Instrumentation const*)&gt;
   0x00000000007551c4 &lt;+24&gt;:    and     x0, x0, #0x1
   0x00000000007551c8 &lt;+28&gt;:    ldp     x29, x30, [sp], #16
   0x00000000007551cc &lt;+32&gt;:    ret
End of assembler dump.</code></pre></code></pre>
</div>
<p>frida 的代码实现为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-48" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">parseArm64InstrumentationOffset</span> <span class="p">(</span><span class="nx">insn</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">insn</span><span class="p">.</span><span class="nx">mnemonic</span> <span class="o">!==</span> <span class="s1">&#39;add&#39;</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">ops</span> <span class="o">=</span> <span class="nx">insn</span><span class="p">.</span><span class="nx">operands</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">ops</span><span class="p">.</span><span class="nx">length</span> <span class="o">!==</span> <span class="mi">3</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">op2</span> <span class="o">=</span> <span class="nx">ops</span><span class="p">[</span><span class="mi">2</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">op2</span><span class="p">.</span><span class="nx">type</span> <span class="o">!==</span> <span class="s1">&#39;imm&#39;</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">op2</span><span class="p">.</span><span class="nx">value</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中 <code>insn</code> 是 <code>Instruction</code> 类型，是 frida 中用以解析汇编指令的关键类，这里不再赘述。另外一个属性 <code>jni_ids_indirection_</code> 的查找也是类似套路，有点类似漏洞利用过程中寻找 gadget 的过程。</p>
<h3 id="trampoline" class="headerLink">
    <a href="#trampoline" class="header-mark"></a>Trampoline</h3><p>根据上面获取到的各个重要字段在 <strong>art::Runtime</strong> 中的偏移后，就可以计算出这些属性在目标内存中的实际地址了。另外一个重要的数据结构是 <strong>art::ClassLinker</strong>，其中包含了 ART hook 所需要的几个重要的共享跳板代码地址，即 trampoline，如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
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    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-49" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">class</span> <span class="nc">ClassLinker</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="p">...</span>
</span></span><span class="line"><span class="cl"><span class="n">InternTable</span><span class="o">*</span> <span class="n">intern_table_</span><span class="p">;</span>                        <span class="c1">// &lt;-- We find this then calculate our way forwards
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_resolution_trampoline_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_imt_conflict_trampoline_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_generic_jni_trampoline_</span><span class="p">;</span>         <span class="c1">// &lt;-- ...to this
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_to_interpreter_bridge_trampoline_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">...</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p><code>intern_table_</code> 的地址我们已经在 art::Runtime 中获得了，因此可以用前面类似的搜索方法依次找出这几个 trampoline 的地址。需要注意的是在 Android 5.x 和 6.x 之后 ClassLinker 的数据结构有所不同，frida 针对这两种情况都分别进行了处理。</p>
<p>quick trampoline 一般是指被编译成 native 代码后的字节码在运行过程中所使用到的跳转地址表，比如 <code>quick_resolution_trampoline_</code> 所指向的 stub 作用就是给(native 代码)第一次调用某个方法时候解析指定方法，同理 <code>generic_jni_trampoline</code> 就是用来跳转到 JNI 方法(代码) 的 stub，<code>quick_to_interpreter_bridge_trampoline_</code> 则是用来从 native 代码跳转到解释器执行的 stub。</p>
<h3 id="其他" class="headerLink">
    <a href="#%e5%85%b6%e4%bb%96" class="header-mark"></a>其他</h3><p>在获取完各个地址后，<code>android.js</code> 中初始化了一个全局的变量 artController，其中主要包含一个 CModule，用以保存、搜索、当前进程的 hook 方法信息，方法的值是 ArtMethod 指针，数据保存在全局的线程安全哈希表中。 C 代码的部分关键实现如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
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          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-50" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="nf">init</span> <span class="p">(</span><span class="kt">void</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nf">g_mutex_init</span> <span class="p">(</span><span class="o">&amp;</span><span class="n">lock</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">methods</span> <span class="o">=</span> <span class="nf">g_hash_table_new_full</span> <span class="p">(</span><span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">replacements</span> <span class="o">=</span> <span class="nf">g_hash_table_new_full</span> <span class="p">(</span><span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kt">void</span> <span class="nf">set_replacement_method</span> <span class="p">(</span><span class="n">gpointer</span> <span class="n">original_method</span><span class="p">,</span> <span class="n">gpointer</span> <span class="n">replacement_method</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nf">g_mutex_lock</span> <span class="p">(</span><span class="o">&amp;</span><span class="n">lock</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nf">g_hash_table_insert</span> <span class="p">(</span><span class="n">methods</span><span class="p">,</span> <span class="n">original_method</span><span class="p">,</span> <span class="n">replacement_method</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nf">g_hash_table_insert</span> <span class="p">(</span><span class="n">replacements</span><span class="p">,</span> <span class="n">replacement_method</span><span class="p">,</span> <span class="n">original_method</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nf">g_mutex_unlock</span> <span class="p">(</span><span class="o">&amp;</span><span class="n">lock</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>同时在 CModule 中还定义若干个 native 方法用以实现一些高频调用的函数 hook，比如:</p>
<ul>
<li>on_interpreter_do_call</li>
<li>on_art_method_get_oat_quick_method_header</li>
<li>on_art_method_pretty_method</li>
<li>on_leave_gc_concurrent_copying_copying_phase</li>
</ul>
<p>最后获取了 C++ 的 new 和 delete 函数地址，以及根据运行时确定 <code>MethodMangler</code> 所属类，完成整个 API 的初始化。MethodMangler 类是对一个指定 Java 方法的封装，实现了调用、劫持、还原等操作，在后文还会继续进行介绍。</p>
<h2 id="vm" class="headerLink">
    <a href="#vm" class="header-mark"></a>VM</h2><p>VM 顾名思义，是对 Java 虚拟机的封装，更准确地说是实现了对 <code>JavaVM *</code> 的封装，包括下面的接口:</p>
<ul>
<li>attachCurrentThread</li>
<li>detachCurrentThread</li>
<li>getEnv</li>
<li>&hellip;</li>
</ul>
<p>值得一提的是初始化的地方:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
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    tw-flex-1 
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    <button 
      class="
        code-block-button
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      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
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      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-51" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
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      "><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">initialize</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">vtable</span> <span class="o">=</span> <span class="nx">handle</span><span class="p">.</span><span class="nx">readPointer</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">options</span> <span class="o">=</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">exceptions</span><span class="o">:</span> <span class="s1">&#39;propagate&#39;</span>
</span></span><span class="line"><span class="cl">  <span class="p">};</span>
</span></span><span class="line"><span class="cl">  <span class="nx">attachCurrentThread</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">NativeFunction</span><span class="p">(</span><span class="nx">vtable</span><span class="p">.</span><span class="nx">add</span><span class="p">(</span><span class="mi">4</span> <span class="o">*</span> <span class="nx">pointerSize</span><span class="p">).</span><span class="nx">readPointer</span><span class="p">(),</span> <span class="s1">&#39;int32&#39;</span><span class="p">,</span> <span class="p">[</span><span class="s1">&#39;pointer&#39;</span><span class="p">,</span> <span class="s1">&#39;pointer&#39;</span><span class="p">,</span> <span class="s1">&#39;pointer&#39;</span><span class="p">],</span> <span class="nx">options</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">detachCurrentThread</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">NativeFunction</span><span class="p">(</span><span class="nx">vtable</span><span class="p">.</span><span class="nx">add</span><span class="p">(</span><span class="mi">5</span> <span class="o">*</span> <span class="nx">pointerSize</span><span class="p">).</span><span class="nx">readPointer</span><span class="p">(),</span> <span class="s1">&#39;int32&#39;</span><span class="p">,</span> <span class="p">[</span><span class="s1">&#39;pointer&#39;</span><span class="p">],</span> <span class="nx">options</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">getEnv</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">NativeFunction</span><span class="p">(</span><span class="nx">vtable</span><span class="p">.</span><span class="nx">add</span><span class="p">(</span><span class="mi">6</span> <span class="o">*</span> <span class="nx">pointerSize</span><span class="p">).</span><span class="nx">readPointer</span><span class="p">(),</span> <span class="s1">&#39;int32&#39;</span><span class="p">,</span> <span class="p">[</span><span class="s1">&#39;pointer&#39;</span><span class="p">,</span> <span class="s1">&#39;pointer&#39;</span><span class="p">,</span> <span class="s1">&#39;int32&#39;</span><span class="p">],</span> <span class="nx">options</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p><code>handle</code> 是构造函数传入的 <code>api.vm</code>，即前文说到的 <code>JNI_GetCreatedJavaVMs</code> 调用的结果，其指针类型是 <code>JavaVM *</code>，内存布局如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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      aria-hidden="true">
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

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        class="
          wrap-code-button
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      <button 
        class="
          copy-code-button
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          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
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      <button 
        class="
          tw-select-none 
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          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-52" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="cp">#ifdef __cplusplus
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="k">typedef</span> <span class="n">JavaVM_</span> <span class="n">JavaVM</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="cp">#else
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="k">typedef</span> <span class="k">const</span> <span class="k">struct</span> <span class="nc">JNIInvokeInterface_</span> <span class="o">*</span><span class="n">JavaVM</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="k">struct</span> <span class="nc">JavaVM_</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="k">struct</span> <span class="nc">JNIInvokeInterface_</span> <span class="o">*</span><span class="n">functions</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="cp">#ifdef __cplusplus
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="nf">DestroyJavaVM</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">functions</span><span class="o">-&gt;</span><span class="n">DestroyJavaVM</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="nf">AttachCurrentThread</span><span class="p">(</span><span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="kt">void</span> <span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">functions</span><span class="o">-&gt;</span><span class="n">AttachCurrentThread</span><span class="p">(</span><span class="k">this</span><span class="p">,</span> <span class="n">penv</span><span class="p">,</span> <span class="n">args</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="nf">DetachCurrentThread</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">functions</span><span class="o">-&gt;</span><span class="n">DetachCurrentThread</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="nf">GetEnv</span><span class="p">(</span><span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="n">jint</span> <span class="n">version</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">functions</span><span class="o">-&gt;</span><span class="n">GetEnv</span><span class="p">(</span><span class="k">this</span><span class="p">,</span> <span class="n">penv</span><span class="p">,</span> <span class="n">version</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="nf">AttachCurrentThreadAsDaemon</span><span class="p">(</span><span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="kt">void</span> <span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">functions</span><span class="o">-&gt;</span><span class="n">AttachCurrentThreadAsDaemon</span><span class="p">(</span><span class="k">this</span><span class="p">,</span> <span class="n">penv</span><span class="p">,</span> <span class="n">args</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="p">};</span></span></span></code></pre>
</div>
<p>这是兼容 C 和 C++ 的写法，由于 ART 虚拟机是用 C++ 写的，因此要想找到这几个函数的地址，首先需要获得 <code>JNIInvokeInterface_</code> 的地址，其正好是 <code>JavaVM</code> 的第一个元素。然后再根据下面的偏移即可获取到 <code>AttachCurrentThread</code> 等函数的实际地址。</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
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    tw-flex-1 
    tw-justify-between 
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    ">      
    <button 
      class="
        code-block-button
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
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          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
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      <button 
        class="
          copy-code-button
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          tw-mx-2 
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          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-53" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">struct</span> <span class="nc">JNIInvokeInterface_</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kt">void</span> <span class="o">*</span><span class="n">reserved0</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kt">void</span> <span class="o">*</span><span class="n">reserved1</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kt">void</span> <span class="o">*</span><span class="n">reserved2</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="p">(</span><span class="n">JNICALL</span> <span class="o">*</span><span class="n">DestroyJavaVM</span><span class="p">)(</span><span class="n">JavaVM</span> <span class="o">*</span><span class="n">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="p">(</span><span class="n">JNICALL</span> <span class="o">*</span><span class="n">AttachCurrentThread</span><span class="p">)(</span><span class="n">JavaVM</span> <span class="o">*</span><span class="n">vm</span><span class="p">,</span> <span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="kt">void</span> <span class="o">*</span><span class="n">args</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="p">(</span><span class="n">JNICALL</span> <span class="o">*</span><span class="n">DetachCurrentThread</span><span class="p">)(</span><span class="n">JavaVM</span> <span class="o">*</span><span class="n">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="p">(</span><span class="n">JNICALL</span> <span class="o">*</span><span class="n">GetEnv</span><span class="p">)(</span><span class="n">JavaVM</span> <span class="o">*</span><span class="n">vm</span><span class="p">,</span> <span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="n">jint</span> <span class="n">version</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="p">(</span><span class="n">JNICALL</span> <span class="o">*</span><span class="n">AttachCurrentThreadAsDaemon</span><span class="p">)(</span><span class="n">JavaVM</span> <span class="o">*</span><span class="n">vm</span><span class="p">,</span> <span class="kt">void</span> <span class="o">**</span><span class="n">penv</span><span class="p">,</span> <span class="kt">void</span> <span class="o">*</span><span class="n">args</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">};</span></span></span></code></pre>
</div>
<h2 id="classfactory" class="headerLink">
    <a href="#classfactory" class="header-mark"></a>ClassFactory</h2><p>在 Runtime 中最后一个初始化的属性是 <code>ClassFactory</code>，虽然它其貌不扬，但却是很多核心操作的实施者，比如通过类名获取目标类的接口 <code>Java.use</code>，又或者是获取某个类在内存中实例的接口 <code>Java.choose</code>，等等。</p>
<p>在平时对一些 APP 进行测试的时候，我们会发现 frida 对于一些加壳的 APP 也同样能够进行注入和劫持，即便是类似 libjiagu 这种动态修改 ClassLoader 的壳，那么 frida 是如何查找类的呢？或者说，是如何找到被加固的类所属的 ClassLoader 的呢？还有 <code>Java.choose</code> 为什么可以找到类的示例，原理是什么？……</p>
<h3 id="类查找" class="headerLink">
    <a href="#%e7%b1%bb%e6%9f%a5%e6%89%be" class="header-mark"></a>类查找</h3><p>了解 frida 的人可能都知道，我们一般使用 <code>Java.use</code> 来获取目标类的 Wrapper，其实现为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-54" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">use</span> <span class="p">(</span><span class="nx">className</span><span class="p">,</span> <span class="nx">options</span> <span class="o">=</span> <span class="p">{})</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">allowCached</span> <span class="o">=</span> <span class="nx">options</span><span class="p">.</span><span class="nx">cache</span> <span class="o">!==</span> <span class="s1">&#39;skip&#39;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="kd">let</span> <span class="nx">C</span> <span class="o">=</span> <span class="nx">allowCached</span> <span class="o">?</span> <span class="k">this</span><span class="p">.</span><span class="nx">_getUsedClass</span><span class="p">(</span><span class="nx">className</span><span class="p">)</span> <span class="o">:</span> <span class="kc">undefined</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">C</span> <span class="o">===</span> <span class="kc">undefined</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">env</span> <span class="o">=</span> <span class="nx">vm</span><span class="p">.</span><span class="nx">getEnv</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="p">{</span> <span class="nx">_loader</span><span class="o">:</span> <span class="nx">loader</span> <span class="p">}</span> <span class="o">=</span> <span class="k">this</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">getClassHandle</span> <span class="o">=</span> <span class="p">(</span><span class="nx">loader</span> <span class="o">!==</span> <span class="kc">null</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="o">?</span> <span class="nx">makeLoaderClassHandleGetter</span><span class="p">(</span><span class="nx">className</span><span class="p">,</span> <span class="nx">loader</span><span class="p">,</span> <span class="nx">env</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="o">:</span> <span class="nx">makeBasicClassHandleGetter</span><span class="p">(</span><span class="nx">className</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="nx">C</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">_make</span><span class="p">(</span><span class="nx">className</span><span class="p">,</span> <span class="nx">getClassHandle</span><span class="p">,</span> <span class="nx">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">finally</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">if</span> <span class="p">(</span><span class="nx">allowCached</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="p">.</span><span class="nx">_setUsedClass</span><span class="p">(</span><span class="nx">className</span><span class="p">,</span> <span class="nx">C</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">      <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">C</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>可能很多人都不知道 use 还可以携带第二个 options 参数，可用于指定是否缓存查找的结果。除去缓存的逻辑，如果没有特殊指定 loader，那么将会使用 <code>makeBasicClassHandleGetter</code> 来获取对应类的查找方法:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-55" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">makeBasicClassHandleGetter</span> <span class="p">(</span><span class="nx">className</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">canonicalClassName</span> <span class="o">=</span> <span class="nx">className</span><span class="p">.</span><span class="nx">replace</span><span class="p">(</span><span class="sr">/\./g</span><span class="p">,</span> <span class="s1">&#39;/&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="kd">function</span> <span class="p">(</span><span class="nx">env</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">tid</span> <span class="o">=</span> <span class="nx">getCurrentThreadId</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="nx">ignore</span><span class="p">(</span><span class="nx">tid</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">return</span> <span class="nx">env</span><span class="p">.</span><span class="nx">findClass</span><span class="p">(</span><span class="nx">canonicalClassName</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">finally</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">unignore</span><span class="p">(</span><span class="nx">tid</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">};</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>这里需要注意的是使用了 <code>env.findClass</code> 来获取类 handle，从名称看也能猜出这是 <code>env-&gt;FindClass</code> 方法，所以 handle 本身是一个 <code>jclass</code> 封装后的对象。<code>_make</code> 方法简化如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-56" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">_make</span> <span class="p">(</span><span class="nx">name</span><span class="p">,</span> <span class="nx">getClassHandle</span><span class="p">,</span> <span class="nx">env</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">C</span> <span class="o">=</span> <span class="nx">makeClassWrapperConstructor</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">proto</span> <span class="o">=</span> <span class="nb">Object</span><span class="p">.</span><span class="nx">create</span><span class="p">(</span><span class="nx">Wrapper</span><span class="p">.</span><span class="nx">prototype</span><span class="p">,</span> <span class="p">{</span> <span class="p">...</span> <span class="p">});</span>
</span></span><span class="line"><span class="cl">  <span class="nx">C</span><span class="p">.</span><span class="nx">prototype</span> <span class="o">=</span> <span class="nx">proto</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">classWrapper</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">C</span><span class="p">(</span><span class="kc">null</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">proto</span><span class="p">.</span><span class="nx">$w</span> <span class="o">=</span> <span class="nx">classWrapper</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">h</span> <span class="o">=</span> <span class="nx">classWrapper</span><span class="p">.</span><span class="nx">$borrowClassHandle</span><span class="p">(</span><span class="nx">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">classHandle</span> <span class="o">=</span> <span class="nx">h</span><span class="p">.</span><span class="nx">value</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="nx">ensureClassInitialized</span><span class="p">(</span><span class="nx">env</span><span class="p">,</span> <span class="nx">classHandle</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">proto</span><span class="p">.</span><span class="nx">$l</span> <span class="o">=</span> <span class="nx">ClassModel</span><span class="p">.</span><span class="nx">build</span><span class="p">(</span><span class="nx">classHandle</span><span class="p">,</span> <span class="nx">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">classWrapper</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>上面省略了一些初始化和异常处理的代码，重要的是最后两个语句，ensureClassInitialized 确保对应类被 Java 虚拟机成功加载:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-57" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">ensureClassInitialized</span> <span class="p">(</span><span class="nx">env</span><span class="p">,</span> <span class="nx">classRef</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">api</span> <span class="o">=</span> <span class="nx">getApi</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">api</span><span class="p">.</span><span class="nx">flavor</span> <span class="o">!==</span> <span class="s1">&#39;art&#39;</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="nx">env</span><span class="p">.</span><span class="nx">getFieldId</span><span class="p">(</span><span class="nx">classRef</span><span class="p">,</span> <span class="s1">&#39;x&#39;</span><span class="p">,</span> <span class="s1">&#39;Z&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">env</span><span class="p">.</span><span class="nx">exceptionClear</span><span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>实现上就是通过 JNI 函数 <code>GetFieldID</code> 来试着取一下目标类的属性，即便该属性不存在，也会触发该类的初始化，当然还需要清理一下 <code>NoSuchFieldException</code> 异常。</p>
<h3 id="类模型" class="headerLink">
    <a href="#%e7%b1%bb%e6%a8%a1%e5%9e%8b" class="header-mark"></a>类模型</h3><p><code>env-&gt;FindClass</code> 仅能找到一个 jclass，frida 在此基础上封装了一个类模型，使用 <code>ClassModel.build</code> 进行创建，其定义在 <code>lib/class-model.js</code> 中。在 Model 里定义了一个 CModule，与 Native 交互比较多或者调用频繁的代码直接使用 C 语言实现(这里主要原因是前者)，包含的函数有:</p>
<ul>
<li>model_new/has/find/list - 用于创建、查找、列举自定义的 <code>Model *</code> 信息；</li>
<li>enumerate_methods_art/jvm - 用于获取指定类的所有方法；</li>
<li>dalloc - 使用 <code>g_free</code> 释放堆内存；</li>
</ul>
<p>看过 ART 源码的同学应该比较熟悉，<code>jclass</code> 本质上是对应 <code>art::mirror::Class</code> 在内存中的地址，在 AOSP 中一般通过下述方式进行转换和使用:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-58" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="kt">void</span> <span class="nf">SomeFunc</span><span class="p">(</span><span class="n">JNIEnv</span> <span class="o">*</span><span class="n">env</span><span class="p">,</span> <span class="n">jclass</span> <span class="n">javaClass</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ScopedObjectAccess</span> <span class="n">soa</span><span class="p">(</span><span class="n">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">c</span> <span class="o">=</span> <span class="n">soa</span><span class="p">.</span><span class="n">Decode</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span><span class="p">(</span><span class="n">javaClass</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>有了 <code>mirror::Class</code> 之后，就可以通过以下的字段去进一步获取类相关信息:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-59" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">// C++ mirror of java.lang.Class
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">class</span> <span class="nc">MANAGED</span> <span class="n">Class</span> <span class="k">final</span> <span class="o">:</span> <span class="k">public</span> <span class="n">Object</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="kt">uint64_t</span> <span class="n">ifields_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="kt">uint64_t</span> <span class="n">methods_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="kt">uint64_t</span> <span class="n">sfields_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="kt">uint32_t</span> <span class="n">access_flags_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="kt">uint16_t</span> <span class="n">copied_methods_offset_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>frida 中根据不同版本的 ART 写死了 <code>ifields_</code> 的偏移，并以此往后计算其他字段，但是 <code>copied_methods_offset_</code> 除外，因为其位置并不固定在上述字段具体位置，因此也需要通过不同的 ART 版本进行确定。</p>
<ul>
<li><strong>ifields_</strong> 表示该类的实例属性(instance fields)，不包含父类所定义的属性。该值为一个指针，指向一个带有长度前缀的 <code>ArtFields</code> 数组；</li>
<li><strong>methods_</strong> 指针同样是带长度前缀的数组，元素类型为 <code>ArtMethod</code>，其中包括所有该类定义的方法。
<ul>
<li><code>virtual_methods_offset_</code> 之前的是直接方法；</li>
<li><code>[virtual_methods_offset_, copied_methods_offset_)</code> 之间的是抽象方法；</li>
<li><code>copied_methods_offset_</code> 之后的是从接口复制过来的默认方法；</li>
</ul>
</li>
<li><strong>sfields_</strong> 和 ifields 类似，区别是表示静态属性；</li>
</ul>
<p>frida 中对类模型的封装是如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-60" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">class</span> <span class="nx">Model</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">static</span> <span class="nx">build</span> <span class="p">(</span><span class="nx">handle</span><span class="p">,</span> <span class="nx">env</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">ensureInitialized</span><span class="p">(</span><span class="nx">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="nx">unwrap</span><span class="p">(</span><span class="nx">handle</span><span class="p">,</span> <span class="nx">env</span><span class="p">,</span> <span class="nx">object</span> <span class="p">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">return</span> <span class="k">new</span> <span class="nx">Model</span><span class="p">(</span><span class="nx">cm</span><span class="p">.</span><span class="k">new</span><span class="p">(</span><span class="nx">handle</span><span class="p">,</span> <span class="nx">object</span><span class="p">,</span> <span class="nx">env</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">    <span class="p">});</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p><code>cm.new</code> 对应 CModule 的 C 函数:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
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      <button 
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    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-61" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="n">Model</span> <span class="o">*</span> <span class="nf">model_new</span> <span class="p">(</span><span class="n">jclass</span> <span class="n">class_handle</span><span class="p">,</span> <span class="n">gpointer</span> <span class="n">class_object</span><span class="p">,</span> <span class="n">JNIEnv</span> <span class="o">*</span> <span class="n">env</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="n">model</span> <span class="o">=</span> <span class="nf">g_new</span> <span class="p">(</span><span class="n">Model</span><span class="p">,</span> <span class="mi">1</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="n">members</span> <span class="o">=</span> <span class="nf">g_hash_table_new_full</span> <span class="p">(</span><span class="n">g_str_hash</span><span class="p">,</span> <span class="n">g_str_equal</span><span class="p">,</span> <span class="n">g_free</span><span class="p">,</span> <span class="n">g_free</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">model</span><span class="o">-&gt;</span><span class="n">members</span> <span class="o">=</span> <span class="n">members</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="n">elements</span> <span class="o">=</span> <span class="nf">read_art_array</span> <span class="p">(</span><span class="n">class_object</span><span class="p">,</span> <span class="n">art_api</span><span class="p">.</span><span class="n">class_offset_methods</span><span class="p">,</span> <span class="k">sizeof</span> <span class="p">(</span><span class="n">gsize</span><span class="p">),</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">n</span> <span class="o">=</span> <span class="o">*</span><span class="p">(</span><span class="n">guint16</span> <span class="o">*</span><span class="p">)</span> <span class="p">(</span><span class="n">class_object</span> <span class="o">+</span> <span class="n">art_api</span><span class="p">.</span><span class="n">class_offset_copied_methods_offset</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// 读取方法
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="k">for</span> <span class="p">(</span><span class="n">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="n">i</span> <span class="o">!=</span> <span class="n">n</span><span class="p">;</span> <span class="n">i</span><span class="o">++</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">jmethodID</span> <span class="n">id</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">guint32</span> <span class="n">access_flags</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">jboolean</span> <span class="n">is_static</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">jobject</span> <span class="n">method</span><span class="p">,</span> <span class="n">name</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="kt">char</span> <span class="o">*</span> <span class="n">name_str</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">jint</span> <span class="n">modifiers</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">id</span> <span class="o">=</span> <span class="n">elements</span> <span class="o">+</span> <span class="p">(</span><span class="n">i</span> <span class="o">*</span> <span class="n">art_api</span><span class="p">.</span><span class="n">method_size</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">access_flags</span> <span class="o">=</span> <span class="o">*</span><span class="p">(</span><span class="n">guint32</span> <span class="o">*</span><span class="p">)</span> <span class="p">(</span><span class="n">id</span> <span class="o">+</span> <span class="n">art_api</span><span class="p">.</span><span class="n">method_offset_access_flags</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">((</span><span class="n">access_flags</span> <span class="o">&amp;</span> <span class="n">kAccConstructor</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">0</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">      <span class="k">continue</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">is_static</span> <span class="o">=</span> <span class="p">(</span><span class="n">access_flags</span> <span class="o">&amp;</span> <span class="n">kAccStatic</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">0</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">method</span> <span class="o">=</span> <span class="nf">to_reflected_method</span> <span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">class_handle</span><span class="p">,</span> <span class="n">id</span><span class="p">,</span> <span class="n">is_static</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">name</span> <span class="o">=</span> <span class="nf">call_object_method</span> <span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">method</span><span class="p">,</span> <span class="n">java_api</span><span class="p">.</span><span class="n">method</span><span class="p">.</span><span class="n">get_name</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">name_str</span> <span class="o">=</span> <span class="nf">get_string_utf_chars</span> <span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">modifiers</span> <span class="o">=</span> <span class="n">access_flags</span> <span class="o">&amp;</span> <span class="mh">0xffff</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nf">model_add_method</span> <span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">name_str</span><span class="p">,</span> <span class="n">id</span><span class="p">,</span> <span class="n">modifiers</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// 读取属性
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="k">for</span> <span class="p">(</span><span class="n">field_array_cursor</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="n">field_array_cursor</span> <span class="o">!=</span> <span class="nf">G_N_ELEMENTS</span> <span class="p">(</span><span class="n">field_arrays</span><span class="p">);</span> <span class="n">field_array_cursor</span><span class="o">++</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nf">model_add_field</span> <span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">name_str</span><span class="p">,</span> <span class="n">id</span><span class="p">,</span> <span class="n">modifiers</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="n">model</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>可见，对应 Class 的方法和属性都会保存在 Model 中的哈希表中，在我们使用对应 ClassWrapper 访问属性时候就可以通过接口进行快速地查找。注意这里哈希表的 key 是方法名称，value 是方法类型、<code>jmethodId</code> 以及重载信息，后续需要调用或者 hook 对应方法的时候才进行实际的方法模型构建操作。</p>
<h1 id="art-hook" class="headerLink">
    <a href="#art-hook" class="header-mark"></a>ART Hook</h1><p>前面介绍完了 <code>Java.use</code> 的具体实现，即类的查找和封装操作，下一步自然是针对方法的实现分析。前面分析 API 初始化的末尾处我们看到指定了 MethodMangler 为 <code>ArtMethodMangler</code> 作为方法的封装，本节介绍其具体实现。</p>
<h2 id="methodmangler" class="headerLink">
    <a href="#methodmangler" class="header-mark"></a>MethodMangler</h2><p>MethodMangler 同样是 API 定义的一个工具类，主要功能是用于实现 Java 方法封装和 Hook 操作。</p>
<p>在 Android 中分为 ART 和 Dalvik 两种实现，二者都提供了相同的接口:</p>
<ul>
<li>constructor (methodId)</li>
<li>replace (impl, isInstanceMethod, argTypes, vm, api)</li>
<li>revert (vm)</li>
<li>resolveTarget (wrapper, isInstanceMethod, env, api)</li>
</ul>
<p>每次 hook 指定方法的时候都会使用对应方法的 methodId 构造一个 MethodMangler，然后使用 replace 函数来替换目标方法实现；revert 则用来恢复原来的方法。</p>
<p>回忆使用 frida 进行 Android hook 的典型操作:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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          <p class="tw-select-none !tw-my-1">js</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-62" 
    class="
      chroma 
      !tw-block 
      tw-p-0
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      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">Activity</span> <span class="o">=</span> <span class="nx">Java</span><span class="p">.</span><span class="nx">use</span><span class="p">(</span><span class="s2">&#34;com.evilpan.MainActivity&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="nx">Activity</span><span class="p">.</span><span class="nx">onCreate</span><span class="p">.</span><span class="nx">implementation</span> <span class="o">=</span> <span class="kd">function</span><span class="p">(</span><span class="nx">bundle</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s2">&#34;We&#39;re in!&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="k">this</span><span class="p">.</span><span class="nx">onCreate</span><span class="p">(</span><span class="nx">bundle</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>类初始化的部分前面已经介绍过了，第二行通过指定方法的 implementation 属性赋值来实现函数替换的操作本质上就是通过 MethodMangler 完成的，代码在 <code>lib/class-factory.js</code>，关键部分如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
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          <p class="tw-select-none !tw-my-1">js</p>
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      <button 
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
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          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-63" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="nx">methodPrototype</span> <span class="o">=</span> <span class="nb">Object</span><span class="p">.</span><span class="nx">create</span><span class="p">(</span><span class="nb">Function</span><span class="p">.</span><span class="nx">prototype</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">methodName</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">enumerable</span><span class="o">:</span> <span class="kc">true</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">get</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="k">this</span><span class="p">.</span><span class="nx">_p</span><span class="p">[</span><span class="mi">0</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// holder: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// type: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// handle: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">implementation</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">enumerable</span><span class="o">:</span> <span class="kc">true</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">get</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="kr">const</span> <span class="nx">replacement</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">_r</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="k">return</span> <span class="p">(</span><span class="nx">replacement</span> <span class="o">!==</span> <span class="kc">undefined</span><span class="p">)</span> <span class="o">?</span> <span class="nx">replacement</span> <span class="o">:</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="nx">set</span> <span class="p">(</span><span class="nx">fn</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="kr">const</span> <span class="nx">params</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">_p</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="kr">const</span> <span class="nx">holder</span> <span class="o">=</span> <span class="nx">params</span><span class="p">[</span><span class="mi">1</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">            <span class="kr">const</span> <span class="nx">type</span> <span class="o">=</span> <span class="nx">params</span><span class="p">[</span><span class="mi">2</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">            <span class="k">if</span> <span class="p">(</span><span class="nx">type</span> <span class="o">===</span> <span class="nx">CONSTRUCTOR_METHOD</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="k">throw</span> <span class="k">new</span> <span class="nb">Error</span><span class="p">(</span><span class="s1">&#39;Reimplementing $new is not possible; replace implementation of $init instead&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">            <span class="kr">const</span> <span class="nx">existingReplacement</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">_r</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="k">if</span> <span class="p">(</span><span class="nx">existingReplacement</span> <span class="o">!==</span> <span class="kc">undefined</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="nx">holder</span><span class="p">.</span><span class="nx">$f</span><span class="p">.</span><span class="nx">_patchedMethods</span><span class="p">.</span><span class="k">delete</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">                <span class="kr">const</span> <span class="nx">mangler</span> <span class="o">=</span> <span class="nx">existingReplacement</span><span class="p">.</span><span class="nx">_m</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">                <span class="nx">mangler</span><span class="p">.</span><span class="nx">revert</span><span class="p">(</span><span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">                <span class="k">this</span><span class="p">.</span><span class="nx">_r</span> <span class="o">=</span> <span class="kc">undefined</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">            <span class="k">if</span> <span class="p">(</span><span class="nx">fn</span> <span class="o">!==</span> <span class="kc">null</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="kr">const</span> <span class="p">[</span><span class="nx">methodName</span><span class="p">,</span> <span class="nx">classWrapper</span><span class="p">,</span> <span class="nx">type</span><span class="p">,</span> <span class="nx">methodId</span><span class="p">,</span> <span class="nx">retType</span><span class="p">,</span> <span class="nx">argTypes</span><span class="p">]</span> <span class="o">=</span> <span class="nx">params</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">                <span class="kr">const</span> <span class="nx">replacement</span> <span class="o">=</span> <span class="nx">implement</span><span class="p">(</span><span class="nx">methodName</span><span class="p">,</span> <span class="nx">classWrapper</span><span class="p">,</span> <span class="nx">type</span><span class="p">,</span> <span class="nx">retType</span><span class="p">,</span> <span class="nx">argTypes</span><span class="p">,</span> <span class="nx">fn</span><span class="p">,</span> <span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">                <span class="kr">const</span> <span class="nx">mangler</span> <span class="o">=</span> <span class="nx">makeMethodMangler</span><span class="p">(</span><span class="nx">methodId</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">                <span class="nx">replacement</span><span class="p">.</span><span class="nx">_m</span> <span class="o">=</span> <span class="nx">mangler</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">                <span class="k">this</span><span class="p">.</span><span class="nx">_r</span> <span class="o">=</span> <span class="nx">replacement</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">                <span class="nx">mangler</span><span class="p">.</span><span class="nx">replace</span><span class="p">(</span><span class="nx">replacement</span><span class="p">,</span> <span class="nx">type</span> <span class="o">===</span> <span class="nx">INSTANCE_METHOD</span><span class="p">,</span> <span class="nx">argTypes</span><span class="p">,</span> <span class="nx">vm</span><span class="p">,</span> <span class="nx">api</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">                <span class="nx">holder</span><span class="p">.</span><span class="nx">$f</span><span class="p">.</span><span class="nx">_patchedMethods</span><span class="p">.</span><span class="nx">add</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// returnType: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// argumentTypes: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// canInvokeWith: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// clone: {},
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// invoke: {}
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">});</span></span></span></code></pre>
</div>
<p>当对目标方法赋值时，调用了 set 方法，首先会判断是否之前有替换过，如果有的话直接将原 hook 函数替换，从这里可以看出 frida 在 针对 Java 目前还没有实现多重 hook；对于未 hook 情况，会创建对应的 MethodMangler 并保存到 <code>Method._r._m</code> 中。</p>
<p>值得注意的是 <code>Method._p</code> 属性，这是一个数组，依次包含对应方法的信息:</p>

<div class="table-wrapper">
  <table>
    <thead>
        <tr>
            <th style="text-align: ">idx</th>
            <th style="text-align: ">meaning</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td style="text-align: ">0</td>
            <td style="text-align: ">methodName</td>
        </tr>
        <tr>
            <td style="text-align: ">1</td>
            <td style="text-align: ">classWrapper</td>
        </tr>
        <tr>
            <td style="text-align: ">2</td>
            <td style="text-align: ">type</td>
        </tr>
        <tr>
            <td style="text-align: ">3</td>
            <td style="text-align: ">methodId</td>
        </tr>
        <tr>
            <td style="text-align: ">4</td>
            <td style="text-align: ">retType</td>
        </tr>
        <tr>
            <td style="text-align: ">5</td>
            <td style="text-align: ">argTypes</td>
        </tr>
        <tr>
            <td style="text-align: ">6</td>
            <td style="text-align: ">jniCall</td>
        </tr>
        <tr>
            <td style="text-align: ">7</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
    </tbody>
  </table>
</div>
<p><code>replacement</code> 将用户提供的 hook JavaScript 方法封装后转换成一个 <code>NativeCallbacks</code> 进行后续处理，而实际替换则使用 <code>mangler.replace</code> 进行实现。</p>
<h2 id="方法封装" class="headerLink">
    <a href="#%e6%96%b9%e6%b3%95%e5%b0%81%e8%a3%85" class="header-mark"></a>方法封装</h2><p>上面传给 MehtodMangler 的 methodId 对应 JNI 的 jmethodId，那么问题来了，jmethodId 如何转换成 <code>ArtMethod</code> 指针呢？直觉认为应该和 <code>jclass</code> 差不多，直接强制转换就行了，很可惜这个直觉只对了一半，对于旧版本的 ART 这个猜测是正确的，但是在新版本中进行了部分重构。frida 中使用的是之前保存的一个 ART 函数 <code>art::jni::JniIdManager::DecodeMethodId</code> 来实现。</p>
<p>通过查看 Android 源码可以发现，该方法在一部分情况下是可以直接转换的，但是当使用摇色子模式且 jmethodId 是奇数时，会使用一个静态的哈希表来获取对应的原始指针，如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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    tw-flex-1 
    tw-justify-between 
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    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-64" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">template</span> <span class="o">&lt;</span><span class="k">typename</span> <span class="n">ArtType</span><span class="o">&gt;</span> <span class="n">ArtType</span><span class="o">*</span> <span class="n">JniIdManager</span><span class="o">::</span><span class="n">DecodeGenericId</span><span class="p">(</span><span class="n">uintptr_t</span> <span class="n">t</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetJniIdType</span><span class="p">()</span> <span class="o">==</span> <span class="n">JniIdType</span><span class="o">::</span><span class="n">kIndices</span> <span class="o">&amp;&amp;</span> <span class="p">(</span><span class="n">t</span> <span class="o">%</span> <span class="mi">2</span><span class="p">)</span> <span class="o">==</span> <span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ReaderMutexLock</span> <span class="nf">mu</span><span class="p">(</span><span class="n">Thread</span><span class="o">::</span><span class="n">Current</span><span class="p">(),</span> <span class="o">*</span><span class="n">Locks</span><span class="o">::</span><span class="n">jni_id_lock_</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">size_t</span> <span class="n">index</span> <span class="o">=</span> <span class="n">IdToIndex</span><span class="p">(</span><span class="n">t</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">DCHECK_GT</span><span class="p">(</span><span class="n">GetGenericMap</span><span class="o">&lt;</span><span class="n">ArtType</span><span class="o">&gt;</span><span class="p">().</span><span class="n">size</span><span class="p">(),</span> <span class="n">index</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">GetGenericMap</span><span class="o">&lt;</span><span class="n">ArtType</span><span class="o">&gt;</span><span class="p">().</span><span class="n">at</span><span class="p">(</span><span class="n">index</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">DCHECK_EQ</span><span class="p">((</span><span class="n">t</span> <span class="o">%</span> <span class="mi">2</span><span class="p">),</span> <span class="mi">0u</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="s">&#34;id: &#34;</span> <span class="o">&lt;&lt;</span> <span class="n">t</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="k">reinterpret_cast</span><span class="o">&lt;</span><span class="n">ArtType</span><span class="o">*&gt;</span><span class="p">(</span><span class="n">t</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="n">ArtMethod</span><span class="o">*</span> <span class="n">JniIdManager</span><span class="o">::</span><span class="n">DecodeMethodId</span><span class="p">(</span><span class="n">jmethodID</span> <span class="n">method</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="n">DecodeGenericId</span><span class="o">&lt;</span><span class="n">ArtMethod</span><span class="o">&gt;</span><span class="p">(</span><span class="k">reinterpret_cast</span><span class="o">&lt;</span><span class="n">uintptr_t</span><span class="o">&gt;</span><span class="p">(</span><span class="n">method</span><span class="p">));</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>由于转换方式相对繁琐，因此 frida 没有自己计算，而是通过 JniIdManager 的成员方法来辅助获取。</p>
<h2 id="方法替换" class="headerLink">
    <a href="#%e6%96%b9%e6%b3%95%e6%9b%bf%e6%8d%a2" class="header-mark"></a>方法替换</h2><p>回顾上文介绍的 <code>implementaion.set</code>，其中 Java 方法替换主要就是通过 <code>MethodMangler</code> 的 <code>replace</code> 的方法实现的，这其中是 frida 进行 ART hook 的主要逻辑，需要我们重点关注。</p>
<p>其实在之前的文章 “<a href="https://evilpan.com/2021/12/26/art-internal/" target="_blank" rel="noopener noreferrer">ART 在 Android 安全攻防中的应用</a>” 中已经简要介绍过了 ART Hook 的大致流程。这里再深入介绍一次，当然主要原因是我自己忘得差不多了，学而时习之，不亦悦乎？</p>
<p>在 ART 虚拟机中，对于方法的调用，大部分会调用到 <code>ArtMethod::Invoke</code>，因此我们可以以此为起点理解实际调用的过程。注意是大部分而不是所有，后面会解释为什么。</p>
<p>Invoke 的核心逻辑如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-65" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">ArtMethod</span><span class="o">::</span><span class="n">Invoke</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="kt">uint32_t</span><span class="o">*</span> <span class="n">args</span><span class="p">,</span> <span class="kt">uint32_t</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">JValue</span><span class="o">*</span> <span class="n">result</span><span class="p">,</span> <span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">shorty</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="o">!</span><span class="n">runtime</span><span class="o">-&gt;</span><span class="n">IsStarted</span><span class="p">()</span> <span class="o">||</span> <span class="p">(</span><span class="n">self</span><span class="o">-&gt;</span><span class="n">IsForceInterpreter</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="n">IsProxyMethod</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="n">IsInvokable</span><span class="p">())))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">IsStatic</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">art</span><span class="o">::</span><span class="n">interpreter</span><span class="o">::</span><span class="n">EnterInterpreterFromInvoke</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">                <span class="n">self</span><span class="p">,</span> <span class="k">this</span><span class="p">,</span> <span class="k">nullptr</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="cm">/*stay_in_interpreter=*/</span> <span class="nb">true</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">mirror</span><span class="o">::</span><span class="n">Object</span><span class="o">*</span> <span class="n">receiver</span> <span class="o">=</span> <span class="k">reinterpret_cast</span><span class="o">&lt;</span><span class="n">StackReference</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Object</span><span class="o">&gt;*&gt;</span><span class="p">(</span><span class="o">&amp;</span><span class="n">args</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span><span class="o">-&gt;</span><span class="n">AsMirrorPtr</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">            <span class="n">art</span><span class="o">::</span><span class="n">interpreter</span><span class="o">::</span><span class="n">EnterInterpreterFromInvoke</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="k">this</span><span class="p">,</span> <span class="n">receiver</span><span class="p">,</span> <span class="n">args</span> <span class="o">+</span> <span class="mi">1</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="cm">/*stay_in_interpreter=*/</span> <span class="nb">true</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">IsStatic</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="p">(</span><span class="o">*</span><span class="n">art_quick_invoke_stub</span><span class="p">)(</span><span class="k">this</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">self</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="n">shorty</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="p">(</span><span class="o">*</span><span class="n">art_quick_invoke_static_stub</span><span class="p">)(</span><span class="k">this</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">self</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="n">shorty</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>主要分为两种情况，一种是 ART 未初始化完成或者系统配置强制以解释模式运行，此时则进入解释器；另一种情况是有 native 代码时，比如 JNI 代码、OAT 提前编译过的代码或者 JIT 运行时编译过的代码以及代理方法等，此时则直接跳转到 invoke_stub 去执行。</p>
<p>对于解释执行的情况，也细分为两种情况，一种是真正的解释执行，不断循环解析 CodeItem 中的每条指令并进行解析；另外一种是在当前解释执行遇到 native 方法时，这种情况一般是遇到了 JNI 函数，这时则通过 <code>method-&gt;GetEntryPointFromJni()</code> 获取对应地址进行跳转，所跳转的地址为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-66" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">class</span> <span class="nc">ArtMethod</span> <span class="k">final</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">struct</span> <span class="nc">PtrSizedFields</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Depending on the method type, the data is
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - native method: pointer to the JNI function registered to this method
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//                    or a function to resolve the JNI function,
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - resolution method: pointer to a function to resolve the method and
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//                        the JNI function for @CriticalNative.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - conflict method: ImtConflictTable,
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - abstract/interface method: the single-implementation if any,
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - proxy method: the original interface method or constructor,
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//   - other methods: during AOT the code item offset, at runtime a pointer
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">//                    to the code item.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kt">void</span><span class="o">*</span> <span class="n">data_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Method dispatch from quick compiled code invokes this pointer which may cause bridging into
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// the interpreter.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kt">void</span><span class="o">*</span> <span class="n">entry_point_from_quick_compiled_code_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span> <span class="n">ptr_sized_fields_</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">};</span></span></span></code></pre>
</div>
<p>而对于快速执行的模式是跳转到 stub 代码，以非静态方法为例，该 stub 定义在 <strong>art/runtime/arch/arm64/quick_entrypoints_arm64.S</strong> 文件中，大致作用是将参数保存在对应寄存器中，然后跳转到实际的地址执行:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-67" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="p">.</span><span class="nx">macro</span> <span class="nx">INVOKE_STUB_CALL_AND_RETURN</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">REFRESH_MARKING_REGISTER</span>
</span></span><span class="line"><span class="cl">    <span class="nx">REFRESH_SUSPEND_CHECK_REGISTER</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// load method-&gt; METHOD_QUICK_CODE_OFFSET
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">ldr</span> <span class="nx">x9</span><span class="p">,</span> <span class="p">[</span><span class="nx">x0</span><span class="p">,</span> <span class="err">#</span><span class="nx">ART_METHOD_QUICK_CODE_OFFSET_64</span><span class="p">]</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Branch to method.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">blr</span> <span class="nx">x9</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Pop the ArtMethod* (null), arguments and alignment padding from the stack.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">mov</span> <span class="nx">sp</span><span class="p">,</span> <span class="nx">xFP</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">.</span><span class="nx">endm</span></span></span></code></pre>
</div>
<p><code>x0</code> 的值保存着 ArtMethod 的地址，实际跳转的是对于 ArtMethod 的某个偏移，这个偏移定义在 <strong>art/tools/cpp-define-generator/art_method.def</strong>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-68" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>ASM_DEFINE(ART_METHOD_QUICK_CODE_OFFSET_64,
           art::ArtMethod::EntryPointFromQuickCompiledCodeOffset(art::PointerSize::k64).Int32Value())</code></pre></code></pre>
</div>
<p>对应的正好是 <code>entry_point_from_quick_compiled_code_</code> 属性的偏移:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-69" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="k">constexpr</span> <span class="n">MemberOffset</span> <span class="nf">EntryPointFromQuickCompiledCodeOffset</span><span class="p">(</span><span class="n">PointerSize</span> <span class="n">pointer_size</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="n">MemberOffset</span><span class="p">(</span><span class="n">PtrSizedFieldsOffset</span><span class="p">(</span><span class="n">pointer_size</span><span class="p">)</span> <span class="o">+</span> <span class="n">OFFSETOF_MEMBER</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">      <span class="n">PtrSizedFields</span><span class="p">,</span> <span class="n">entry_point_from_quick_compiled_code_</span><span class="p">)</span> <span class="o">/</span> <span class="k">sizeof</span><span class="p">(</span><span class="kt">void</span><span class="o">*</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">          <span class="o">*</span> <span class="k">static_cast</span><span class="o">&lt;</span><span class="n">size_t</span><span class="o">&gt;</span><span class="p">(</span><span class="n">pointer_size</span><span class="p">));</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>因此，不管是解释模式还是其他模式，只要目标方法有 native 代码，那么该方法的代码地址都是会保存在 <code>entry_point_from_quick_compiled_code_</code> 字段，只不过这个字段的含义在不同的场景中略有不同。</p>
<p>所以我们若想要实现 ART Hook，理论上只要找到对应方法在内存中的 ArtMethod 地址，然后替换其 entrypoint 的值即可。但是前面说过，并不是所有方法都会走到 <code>ArtMethod::Invoke</code>。比如对于系统函数的调用，OAT 优化时会直接将对应系统函数方法的调用替换为汇编跳转，跳转的目的就是就是对应方法的 entrypoint，因为 <code>boot.oat</code> 由 zygote 加载，对于所有应用而言内存地址都是固定的，因此 ART 可以在优化过程中省略方法的查找过程从而直接跳转。</p>
<p>在这样的前提下，再让我们回到 frida 的代码，看它如何能实现针对包括系统函数在内所有方法的 hook。</p>
<p>首先 MethodMangler 接受的是 JNI 层的 <code>jmethodId</code>，通过前面介绍过的转换方法获取到了原始的 <code>ArtMethod</code> 指针，并保存到 <code>methodId</code> 属性中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
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          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-70" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">class</span> <span class="nx">ArtMethodMangler</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">constructor</span> <span class="p">(</span><span class="nx">opaqueMethodId</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">methodId</span> <span class="o">=</span> <span class="nx">unwrapMethodId</span><span class="p">(</span><span class="nx">opaqueMethodId</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">methodId</span> <span class="o">=</span> <span class="nx">methodId</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">originalMethod</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">hookedMethodId</span> <span class="o">=</span> <span class="nx">methodId</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">replacementMethodId</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">interceptor</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span></span></span></code></pre>
</div>
<p>当然 ArtMethod 结构体在不同版本中也是不同的，因此 frida 使用了一种特别的搜索方法来确定 jniCode(即<code>data_</code>)、quickCode、interpreterCode、accessFlag 的偏移，以及 ArtMethod 结构的大小。这些信息保存在 <code>originalMethod</code> 字段。</p>
<p>在执行方法替换的时候，会将原方法拷贝一份，地址保存在 <code>replacementMethodId</code> 中，然后对拷贝的方法进行 patch，主要修改以下几个字段:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-71" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">replacementMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">jniCode</span><span class="o">:</span> <span class="nx">impl</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">accessFlags</span><span class="o">:</span> <span class="p">((</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="o">~</span><span class="p">(</span><span class="nx">kAccCriticalNative</span> <span class="o">|</span> <span class="nx">kAccFastNative</span> <span class="o">|</span> <span class="nx">kAccNterpEntryPointFastPathFlag</span><span class="p">))</span> <span class="o">|</span> <span class="nx">kAccNative</span><span class="p">)</span> <span class="o">&gt;&gt;&gt;</span> <span class="mi">0</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">quickCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artClassLinker</span><span class="p">.</span><span class="nx">quickGenericJniTrampoline</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">interpreterCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artInterpreterToCompiledCodeBridge</span>
</span></span><span class="line"><span class="cl"><span class="p">},</span> <span class="nx">vm</span><span class="p">);</span></span></span></code></pre>
</div>
<p>jniCode 替换为用户指定的 js 函数封装而成的 NativeFunction，并将 accessFlags 设置为 <code>kAccNative</code>，即 JNI 方法。quickCode 和 interpreterCode 分别是 Quick 模式和解释器模式的入口，替换为了上文中查找保存的 trampoline，令 Quick 模式跳转到 JNI 入口，解释器模式跳转到 Quick 代码，这样就实现了该方法的拦截，每次执行都会当做 JNI 函数执行到 jniCode 即我们替换的代码中。</p>
<p>这样就完成了吗？基本功能已经实现了，但是还要处理一些特殊的情况。比如防止解释器模式进入 <code>fast_path</code>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-72" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">let</span> <span class="nx">hookedMethodRemovedFlags</span> <span class="o">=</span> <span class="nx">kAccFastInterpreterToInterpreterInvoke</span> <span class="o">|</span> <span class="nx">kAccSingleImplementation</span> <span class="o">|</span> <span class="nx">kAccNterpEntryPointFastPathFlag</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="k">if</span> <span class="p">((</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="nx">kAccNative</span><span class="p">)</span> <span class="o">===</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">hookedMethodRemovedFlags</span> <span class="o">|=</span> <span class="nx">kAccSkipAccessChecks</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">accessFlags</span><span class="o">:</span> <span class="p">(</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="o">~</span><span class="p">(</span><span class="nx">hookedMethodRemovedFlags</span><span class="p">))</span> <span class="o">&gt;&gt;&gt;</span> <span class="mi">0</span>
</span></span><span class="line"><span class="cl"><span class="p">},</span> <span class="nx">vm</span><span class="p">);</span></span></span></code></pre>
</div>
<p>另外，在 Android 8.0 后的 ART 中，使用了新一代的解释器 <a href="https://source.android.com/devices/tech/dalvik/improvements#interpreter-performance" target="_blank" rel="noopener noreferrer">Nterp(Next-Generation Interpreter)</a>，直接使用汇编实现以提高执行性能和内存使用。</p>
<p>如果待 hook 方法是解释执行，且使用了 nterp，那么 frida 会将其入口替换为  <code>art_quick_to_interpreter_bridge</code> 来跳出解释器，并进入到实际的 quickCode 去执行，从而让我们的方法替换功能保持完整。</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-73" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">const</span> <span class="p">{</span> <span class="nx">artNterpEntryPoint</span> <span class="p">}</span> <span class="o">=</span> <span class="nx">api</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">if</span> <span class="p">(</span><span class="nx">artNterpEntryPoint</span> <span class="o">!==</span> <span class="kc">undefined</span> <span class="o">&amp;&amp;</span> <span class="nx">quickCode</span><span class="p">.</span><span class="nx">equals</span><span class="p">(</span><span class="nx">artNterpEntryPoint</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">quickCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artQuickToInterpreterBridge</span>
</span></span><span class="line"><span class="cl">  <span class="p">},</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>虽然此时我们已经将目标 ArtMethod 改成了 Native 方法，且 JNI 的入口指向我们的 hook 函数，但如果该方法已经被 OAT 或者 JIT 优化成了二进制代码，此时在字节码层调用 <code>invoke-xxx</code> 时会通过方法的 <code>entry_point_from_quick_compiled_code_</code> 直接跳转到 native 代码执行，而不是 <code>quick_xxx_trampoline</code>。</p>
<p>因此对于这种情况，我们可以将 entrypoint 的地址重新指向 trampoline，但如前文所说，对于系统函数而言，其地址已知，因此调用方被优化后很可能直接就调转到了对应的 native 地址，而不会通过 entrypoint 去查找。因此 frida 采用的方法是直接修改目标方法的 quickCode 内容，将其替换为一段跳板代码，然后再间接跳转到我们的劫持实现中。</p>
<p>以 ARM64 为例，trampoline 的部分代码如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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    <button 
      class="
        code-block-button
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      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
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        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
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          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
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        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
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          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
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        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-74" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
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      "><span class="line"><span class="cl"><span class="nx">Memory</span><span class="p">.</span><span class="nx">patchCode</span><span class="p">(</span><span class="nx">trampoline</span><span class="p">,</span> <span class="mi">256</span><span class="p">,</span> <span class="nx">code</span> <span class="p">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">writer</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">Arm64Writer</span><span class="p">(</span><span class="nx">code</span><span class="p">,</span> <span class="p">{</span> <span class="nx">pc</span><span class="o">:</span> <span class="nx">trampoline</span> <span class="p">});</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">relocator</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">Arm64Relocator</span><span class="p">(</span><span class="nx">target</span><span class="p">,</span> <span class="nx">writer</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="c1">// Save FPRs.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;d0&#39;</span><span class="p">,</span> <span class="s1">&#39;d1&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;d2&#39;</span><span class="p">,</span> <span class="s1">&#39;d3&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;d4&#39;</span><span class="p">,</span> <span class="s1">&#39;d5&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;d6&#39;</span><span class="p">,</span> <span class="s1">&#39;d7&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="c1">// Save core args, callee-saves &amp; LR.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x1&#39;</span><span class="p">,</span> <span class="s1">&#39;x2&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x3&#39;</span><span class="p">,</span> <span class="s1">&#39;x4&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x5&#39;</span><span class="p">,</span> <span class="s1">&#39;x6&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x7&#39;</span><span class="p">,</span> <span class="s1">&#39;x20&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x21&#39;</span><span class="p">,</span> <span class="s1">&#39;x22&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x23&#39;</span><span class="p">,</span> <span class="s1">&#39;x24&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x25&#39;</span><span class="p">,</span> <span class="s1">&#39;x26&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x27&#39;</span><span class="p">,</span> <span class="s1">&#39;x28&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putPushRegReg</span><span class="p">(</span><span class="s1">&#39;x29&#39;</span><span class="p">,</span> <span class="s1">&#39;lr&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="c1">// Save ArtMethod* + alignment padding.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="nx">writer</span><span class="p">.</span><span class="nx">putSubRegRegImm</span><span class="p">(</span><span class="s1">&#39;sp&#39;</span><span class="p">,</span> <span class="s1">&#39;sp&#39;</span><span class="p">,</span> <span class="mi">16</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putStrRegRegOffset</span><span class="p">(</span><span class="s1">&#39;x0&#39;</span><span class="p">,</span> <span class="s1">&#39;sp&#39;</span><span class="p">,</span> <span class="mi">0</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="nx">writer</span><span class="p">.</span><span class="nx">putCallAddressWithArguments</span><span class="p">(</span><span class="nx">artController</span><span class="p">.</span><span class="nx">replacedMethods</span><span class="p">.</span><span class="nx">findReplacementFromQuickCode</span><span class="p">,</span> <span class="p">[</span><span class="s1">&#39;x0&#39;</span><span class="p">,</span> <span class="s1">&#39;x19&#39;</span><span class="p">]);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="c1">// 保存调用结果，恢复寄存器 ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>quickCode 的替换使用使用 <code>ArtQuickCodeInterceptor</code> 完成，姑且理解为跳板管理器，保存在 MethodMangler 的 interceptor 属性中，这样在程序退出或者用户调用 <code>method.implementation = null</code> 时还会调用 <code>interceptor.deactivate</code> 恢复方法，防止残留 hook 代码导致的运行时崩溃。</p>
<h1 id="总结" class="headerLink">
    <a href="#%e6%80%bb%e7%bb%93" class="header-mark"></a>总结</h1><p>本文介绍了 frida 针对 ART 运行时的实现，其基本思路是通过运行时中的私有函数来与对应的 Java 虚拟机进行交互，其中大部分操作都基于 gum-js 接口进行实现，包括 Java 类和方法的封装、ART hook 以及 trampoline 汇编的编写等。除了 ART 还实现了 Dalvik 和 JVM 这两个虚拟机的接口，流程大同小异。甚至对于其他语言来说也是类似的，这也得益于 frida 开源社区的活跃性，相信未来会出现对更多高级语言的支持。</p>
<h1 id="参考链接" class="headerLink">
    <a href="#%e5%8f%82%e8%80%83%e9%93%be%e6%8e%a5" class="header-mark"></a>参考链接</h1><ul>
<li><a href="https://github.com/frida/frida-java-bridge" target="_blank" rel="noopener noreferrer">frida-java-bridge</a></li>
<li><a href="https://frida.re/docs/javascript-api/" target="_blank" rel="noopener noreferrer">frida JavaScript API</a></li>
<li><a href="https://github.com/asLody/SandHook/blob/master/doc/doc.md" target="_blank" rel="noopener noreferrer">SandHook - Docs</a></li>
<li><a href="http://rk700.github.io/2017/06/30/hook-on-android-n/" target="_blank" rel="noopener noreferrer">在Android N上对Java方法做hook遇到的坑</a></li>
<li><a href="https://weishu.me/2017/11/23/dexposed-on-art/" target="_blank" rel="noopener noreferrer">我为Dexposed续一秒——论ART上运行时 Method AOP实现</a></li>
<li><a href="https://evilpan.com/2021/12/26/art-internal/" target="_blank" rel="noopener noreferrer">ART 在 Android 安全攻防中的应用</a></li>
</ul>
<hr>
<blockquote>
  <p><strong>版权声明</strong>: 自由转载-非商用-非衍生-保持署名 (<a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noopener noreferrer">CC 4.0 BY-SA</a>)<br>
<strong>原文地址</strong>: <a href="https://evilpan.com/2022/04/17/frida-java/" target="_blank" rel="noopener noreferrer">https://evilpan.com/2022/04/17/frida-java/</a><br>
<strong>微信订阅</strong>: <strong>『<a href="http://t.evilpan.com/qrcode.jpg" target="_blank" rel="noopener noreferrer">有价值炮灰</a>』</strong><br>
&ndash; <em>TO BE CONTINUED</em>.</p>
</blockquote><hr>]]></description>
</item><item>
    <title>Frida Internal - Part 2: 核心组件 frida-core</title>
    <link>https://evilpan.com/2022/04/09/frida-core/</link>
    <pubDate>Sat, 09 Apr 2022 12:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2022/04/09/frida-core/</guid>
    <description><![CDATA[<p>前文已经介绍了 frida 中的核心组件 <code>frida-gum</code> 以及对应的 js 接口 <code>gum-js</code>，但仅有这些基础功能并不能让 frida 成为如此受欢迎的 Instrumentation (hook) 框架。为了实现一个完善框架或者说工具，需要实现许多系统层的功能。比如进程注入、进程间通信、会话管理、脚本生命周期管理等功能，屏蔽部分底层的实现细节并给最终用户提供开箱即用的操作接口。而这一切的实现都在 <code>frida-core</code> 之中，正如名字所言，这其中包含了 frida 相关的大部分关键模块和组件，比如 frida-server、frida-gadget、frida-agent、frida-helper、frida-inject 以及之间的互相通信底座。本文主要节选其中关键的部分进行分析和介绍。</p>
<p>传送门:</p>
<ul>
<li><a href="https://evilpan.com/2022/04/05/frida-internal/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 1: 架构、Gum 与 V8</a></li>
<li><a href="https://evilpan.com/2022/04/09/frida-core/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 2: frida-core  (本文)</a></li>
<li><a href="https://evilpan.com/2022/04/17/frida-java/" target="_blank" rel="noopener noreferrer">Frida Internal - Part 3: frida-java-bridge 与 ART hook</a></li>
</ul>
<h1 id="vala" class="headerLink">
    <a href="#vala" class="header-mark"></a>Vala</h1><p>如果曾经浏览过 frida-core 的代码，会发现其大部分源文件都是 <em>.vala</em> 后缀的。这其实是 GNOME 中使用的一个高级语言，和传统高级语言不同的是 vala 代码会被编译器先编译成 C 代码，然后再编译成二进制文件，因此也可以认为 vala 语言是 C 的一个语法糖拓展。</p>
<p><a href="https://wiki.gnome.org/Projects/Vala/" target="_blank" rel="noopener noreferrer">Vala</a> 使用 glib 的 <code>GObject</code> 类型系统来构造类和接口以实现面向对象，其语法有点类似于 <code>C#</code>，支持许多现代语言的高级特性，包括但不限于接口、属性、内存管理、异常、lambda、信号等等。Vala 既可以通过 API 文件访问已有的 C 库文件，也可以从 C 中很容易调用 Vala 的方法。</p>
<p>一个简单的 Vala 代码示例如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
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    <button 
      class="
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      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
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      </button>

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      <button 
        class="
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          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-1" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">// test.vala
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="kt">int</span> <span class="nf">main</span> <span class="p">(</span><span class="n">string</span><span class="p">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">stdout</span><span class="p">.</span><span class="nf">printf</span> <span class="p">(</span><span class="s">&#34;nargs=%d</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">,</span> <span class="n">args</span><span class="p">.</span><span class="n">length</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nf">foreach</span> <span class="p">(</span><span class="n">string</span> <span class="n">arg</span> <span class="n">in</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">stdout</span><span class="p">.</span><span class="nf">printf</span> <span class="p">(</span><span class="s">&#34;%s</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">,</span> <span class="n">arg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="mi">0</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>编译运行也非常简单:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

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      <button 
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        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-2" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ valac test.vala
</span></span><span class="line"><span class="cl">$ ./test hello world
</span></span><span class="line"><span class="cl"><span class="nv">nargs</span><span class="o">=</span><span class="m">3</span>
</span></span><span class="line"><span class="cl">./test
</span></span><span class="line"><span class="cl">hello
</span></span><span class="line"><span class="cl">world
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">$ rabin2 -l <span class="nb">test</span>
</span></span><span class="line"><span class="cl"><span class="o">[</span>Linked libraries<span class="o">]</span>
</span></span><span class="line"><span class="cl">libglib-2.0.so.0
</span></span><span class="line"><span class="cl">libc.so.6
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="m">2</span> libraries</span></span></code></pre>
</div>
<p>Vala 程序也可以直接编译为 C 代码，使用 <code>valac -C test.vala</code> 即可生成对应的 <code>test.c</code> 文件。
更多的示例程序可以查看 <a href="https://wiki.gnome.org/Projects/Vala/Documentation#Sample_Code" target="_blank" rel="noopener noreferrer">Vala 的官方文档</a>。</p>
<h1 id="接口" class="headerLink">
    <a href="#%e6%8e%a5%e5%8f%a3" class="header-mark"></a>接口</h1><p>在上文中我们介绍了 frida-gum 和 gum-js，这二者都有对应的 release devkit 可以下载，frida-core 也一样。我们在 frida-core-devkit 中可以获取到编译好的静态库、头文件以及简单的示例程序，下面就以接口为着手点进行分析。</p>
<p>以 Android 平台为例，最常用的方式是先将 <code>frida-server</code> 推送到设备端启动，然后在本地使用 <code>frida-tools</code> 去加载 JS 脚本并执行 hook 操作。<code>frida-tools</code> 是基于 Python 的 binding 编写的，本质上还是调用了 <code>frida-core</code>，连接设备并加载脚本的过程如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-3" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">// 获取设备句柄
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">FridaManager</span> <span class="o">*</span><span class="n">manager</span> <span class="o">=</span> <span class="nf">frida_device_manager_new</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="n">FridaDeviceList</span> <span class="o">*</span><span class="n">devices</span> <span class="o">=</span> <span class="nf">frida_device_manager_enumerate_devices_sync</span> <span class="p">(</span><span class="n">manager</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">error</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="n">FridaDevice</span> <span class="o">*</span> <span class="n">local_device</span> <span class="o">=</span> <span class="nf">frida_device_list_get</span> <span class="p">(</span><span class="n">devices</span><span class="p">,</span> <span class="n">i</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 连接设备上的指定进程
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">FridaSession</span> <span class="o">*</span><span class="n">session</span> <span class="o">=</span> <span class="nf">frida_device_attach_sync</span> <span class="p">(</span><span class="n">local_device</span><span class="p">,</span> <span class="n">target_pid</span><span class="p">,</span> <span class="n">FRIDA_REALM_NATIVE</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">error</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 创建脚本
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">options</span> <span class="o">=</span> <span class="nf">frida_script_options_new</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="nf">frida_script_options_set_name</span> <span class="p">(</span><span class="n">options</span><span class="p">,</span> <span class="s">&#34;example&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="nf">frida_script_options_set_runtime</span> <span class="p">(</span><span class="n">options</span><span class="p">,</span> <span class="n">FRIDA_SCRIPT_RUNTIME_QJS</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="n">script</span> <span class="o">=</span> <span class="nf">frida_session_create_script_sync</span> <span class="p">(</span><span class="n">session</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">         <span class="s">&#34;console.log(&#39;hello&#39;);&#34;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">         <span class="n">options</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">error</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 加载脚本
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="nf">g_signal_connect</span> <span class="p">(</span><span class="n">script</span><span class="p">,</span> <span class="s">&#34;message&#34;</span><span class="p">,</span> <span class="nf">G_CALLBACK</span> <span class="p">(</span><span class="n">on_message</span><span class="p">),</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="nf">frida_script_load_sync</span> <span class="p">(</span><span class="n">script</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">error</span><span class="p">);</span></span></span></code></pre>
</div>
<p>虽然这里用的是 C 的接口，但实际上代码是在 <code>vala</code> 中以类方法的方式定义的，以 <code>frida_device_attach_sync</code> 这个方法为例，其定义在 <code>src/frida.vala</code> 中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-4" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">namespace</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kr">public</span> <span class="kr">class</span> <span class="nx">Device</span> <span class="o">:</span> <span class="nb">Object</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="kr">public</span> <span class="nx">Session</span> <span class="nx">attach_sync</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">SessionOptions</span><span class="o">?</span> <span class="nx">options</span> <span class="o">=</span> <span class="kc">null</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span> <span class="o">=</span> <span class="kc">null</span><span class="p">)</span> <span class="kr">throws</span> <span class="nb">Error</span><span class="p">,</span> <span class="nx">IOError</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="kd">var</span> <span class="nx">task</span> <span class="o">=</span> <span class="nx">create</span><span class="o">&lt;</span><span class="nx">AttachTask</span><span class="o">&gt;</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">            <span class="nx">task</span><span class="p">.</span><span class="nx">pid</span> <span class="o">=</span> <span class="nx">pid</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="nx">task</span><span class="p">.</span><span class="nx">options</span> <span class="o">=</span> <span class="nx">options</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">            <span class="k">return</span> <span class="nx">task</span><span class="p">.</span><span class="nx">execute</span> <span class="p">(</span><span class="nx">cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>因此 vala 编译后的 C 代码符号也是可以比较容易对应到实际代码的，这对于开发和调试有很大的帮助。</p>
<h1 id="frida-server" class="headerLink">
    <a href="#frida-server" class="header-mark"></a>frida-server</h1><p>虽然连接、加载脚本的逻辑是在 PC 端编写和执行的，但实际操作还是在设备端，即 <code>frida-server</code> 所运行的系统中。</p>
<p>该进程的主函数定义在 <code>server/server.vala</code> 中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-5" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">namespace</span> <span class="nx">Frida</span><span class="p">.</span><span class="nx">Server</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="kr">private</span> <span class="kr">static</span> <span class="kr">int</span> <span class="nx">main</span> <span class="p">(</span><span class="nx">string</span><span class="p">[]</span> <span class="nx">args</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Environment</span><span class="p">.</span><span class="nx">init</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">return</span> <span class="nx">run_application</span> <span class="p">(</span><span class="nx">endpoint_params</span><span class="p">,</span> <span class="nx">options</span><span class="p">,</span> <span class="nx">on_ready</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="kr">private</span> <span class="kr">static</span> <span class="kr">int</span> <span class="nx">run_application</span> <span class="p">(</span><span class="nx">EndpointParameters</span> <span class="nx">endpoint_params</span><span class="p">,</span> <span class="nx">ControlServiceOptions</span> <span class="nx">options</span><span class="p">,</span> <span class="nx">ReadyHandler</span> <span class="nx">on_ready</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">TemporaryDirectory</span><span class="p">.</span><span class="nx">always_use</span> <span class="p">((</span><span class="nx">directory</span> <span class="o">!=</span> <span class="kc">null</span><span class="p">)</span> <span class="o">?</span> <span class="nx">directory</span> <span class="o">:</span> <span class="nx">DEFAULT_DIRECTORY</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">application</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">Application</span> <span class="p">(</span><span class="k">new</span> <span class="nx">ControlService</span> <span class="p">(</span><span class="nx">endpoint_params</span><span class="p">,</span> <span class="nx">options</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">return</span> <span class="nx">application</span><span class="p">.</span><span class="nx">run</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p><code>Application</code> 实际上是一层简单的封装，其 <code>run</code> 方法会间接调用到 <code>servcie.start</code>，即构造函数中传入的 <code>ControlService</code>。该类定义在 <em>src/control-service.vala</em> 中，包含 3 个主要的属性:</p>
<ul>
<li>HostSession host_session</li>
<li>EndpointParameters endpoint_params</li>
<li>ControlServiceOptions options</li>
</ul>
<p>其中最重要的是 <code>HostSession</code>，该属性是一个接口类型，基于面向对象的多态方式实现了不同平台下的实现，如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
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        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
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        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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        aria-hidden="true"><svg class="icon"
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    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-6" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="n">public</span> <span class="nf">ControlService</span> <span class="p">(</span><span class="n">EndpointParameters</span> <span class="n">endpoint_params</span><span class="p">,</span> <span class="n">ControlServiceOptions</span><span class="o">?</span> <span class="n">options</span> <span class="o">=</span> <span class="n">null</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">HostSession</span> <span class="n">host_session</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="cp">#if WINDOWS
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>    <span class="n">var</span> <span class="n">tempdir</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">TemporaryDirectory</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">host_session</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">WindowsHostSession</span> <span class="p">(</span><span class="n">new</span> <span class="nf">WindowsHelperProcess</span> <span class="p">(</span><span class="n">tempdir</span><span class="p">),</span> <span class="n">tempdir</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp">#if DARWIN
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>    <span class="n">host_session</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">DarwinHostSession</span> <span class="p">(</span><span class="n">new</span> <span class="nf">DarwinHelperBackend</span> <span class="p">(),</span> <span class="n">new</span> <span class="nf">TemporaryDirectory</span> <span class="p">(),</span>
</span></span><span class="line"><span class="cl">        <span class="n">opts</span><span class="p">.</span><span class="n">report_crashes</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp">#if LINUX
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>    <span class="n">var</span> <span class="n">tempdir</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">TemporaryDirectory</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">host_session</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">LinuxHostSession</span> <span class="p">(</span><span class="n">new</span> <span class="nf">LinuxHelperProcess</span> <span class="p">(</span><span class="n">tempdir</span><span class="p">),</span> <span class="n">tempdir</span><span class="p">,</span> <span class="n">opts</span><span class="p">.</span><span class="n">report_crashes</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp">#if FREEBSD
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>    <span class="n">host_session</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">FreebsdHostSession</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp">#if QNX
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>    <span class="n">host_session</span> <span class="o">=</span> <span class="n">new</span> <span class="nf">QnxHostSession</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif</span></span></span></code></pre>
</div>
<p><code>HostSession</code> 的接口定义在 <em>lib/base/session.vala</em> 中，接口如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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      aria-hidden="true">
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          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
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      <button 
        class="
          wrap-code-button
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      <button 
        class="
          copy-code-button
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          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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      <button 
        class="
          tw-select-none 
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          tw-block 
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        aria-hidden="true"><svg class="icon"
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    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-7" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">interface</span> <span class="nx">HostSession</span> <span class="o">:</span> <span class="nb">Object</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">ping</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">interval_seconds</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">query_system_parameters</span> <span class="p">(</span><span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HostApplicationInfo</span> <span class="nx">get_frontmost_application</span> <span class="p">(</span><span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HostApplicationInfo</span><span class="p">[]</span> <span class="nx">enumerate_applications</span> <span class="p">(</span><span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HostProcessInfo</span><span class="p">[]</span> <span class="nx">enumerate_processes</span> <span class="p">(</span><span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">enable_spawn_gating</span> <span class="p">(</span><span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">disable_spawn_gating</span> <span class="p">(</span><span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HostSpawnInfo</span><span class="p">[]</span> <span class="nx">enumerate_pending_spawn</span> <span class="p">(</span><span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">HostChildInfo</span><span class="p">[]</span> <span class="nx">enumerate_pending_children</span> <span class="p">(</span><span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">uint</span> <span class="nx">spawn</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">program</span><span class="p">,</span> <span class="nx">HostSpawnOptions</span> <span class="nx">options</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">input</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">uint8</span><span class="p">[]</span> <span class="nx">data</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">resume</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">kill</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">AgentSessionId</span> <span class="nx">attach</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="k">void</span> <span class="nx">reattach</span> <span class="p">(</span><span class="nx">AgentSessionId</span> <span class="nx">id</span><span class="p">,</span> <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">InjectorPayloadId</span> <span class="nx">inject_library_file</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">path</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">entrypoint</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">data</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">async</span> <span class="nx">InjectorPayloadId</span> <span class="nx">inject_library_blob</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">uint8</span><span class="p">[]</span> <span class="nx">blob</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">entrypoint</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">data</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">GLib</span><span class="p">.</span><span class="nb">Error</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">spawn_added</span> <span class="p">(</span><span class="nx">HostSpawnInfo</span> <span class="nx">info</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">spawn_removed</span> <span class="p">(</span><span class="nx">HostSpawnInfo</span> <span class="nx">info</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">child_added</span> <span class="p">(</span><span class="nx">HostChildInfo</span> <span class="nx">info</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">child_removed</span> <span class="p">(</span><span class="nx">HostChildInfo</span> <span class="nx">info</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">process_crashed</span> <span class="p">(</span><span class="nx">CrashInfo</span> <span class="nx">crash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">output</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="kr">int</span> <span class="nx">fd</span><span class="p">,</span> <span class="nx">uint8</span><span class="p">[]</span> <span class="nx">data</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">agent_session_detached</span> <span class="p">(</span><span class="nx">AgentSessionId</span> <span class="nx">id</span><span class="p">,</span> <span class="nx">SessionDetachReason</span> <span class="nx">reason</span><span class="p">,</span> <span class="nx">CrashInfo</span> <span class="nx">crash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">uninjected</span> <span class="p">(</span><span class="nx">InjectorPayloadId</span> <span class="nx">id</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中包括了应用枚举、进程查找、进程注入、进程启动以及各类信号回调的接口原型，基于这些接口实现对目标进程的劫持和动态修改。由于我们重点是分析 Android 系统上的实现，因此后文主要分析 <code>LinuxHostSession</code>，对于其他平台的分析也是类似的。</p>
<p><code>LinuxHostSession</code> 的代码在 <em>src/linux/linux-host-session.vala</em> 中，其中定义了几个重要的属性，分别是:</p>
<ul>
<li>injector: 类型为 Linjector</li>
<li>agent: 类型为 AgentDescriptor</li>
<li>system_server_agent: 类型为 SystemServerAgent</li>
<li>robo_launcher: 类型为 RoboLauncher</li>
</ul>
<p>它们都在构造函数中进行初始化，分别实现了进程注入、server 与注入代码之间的进程间通信以及远程调用行为，下文会分别进行简要介绍。</p>
<h2 id="进程注入" class="headerLink">
    <a href="#%e8%bf%9b%e7%a8%8b%e6%b3%a8%e5%85%a5" class="header-mark"></a>进程注入</h2><p>从接口名称来看，进程注入的实现大概率是 <code>inject_library_file</code>，表示注入一个动态库到目标进程中。所注入的动态库称为 agent。</p>
<p>回到注入的实现上，frida-server 是怎么实现进程注入的呢？ 根据已有经验，由于我们以 root 权限启动，在 Linux 中一般有多种实现进程注入的方式，比如 ptrace、<code>/proc/pid/mem</code>，DLL/SO 劫持、LD_PERLOAD 等，因此实际实现还要回到代码。</p>
<p>Android 中实现进程注入的方法如下:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-8" 
    class="
      chroma 
      !tw-block 
      tw-p-0
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      tw-transition-[max-height] 
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      "><span class="line"><span class="cl"><span class="kr">protected</span> <span class="nx">override</span> <span class="kr">async</span> <span class="nx">Future</span><span class="o">&lt;</span><span class="nx">IOStream</span><span class="o">&gt;</span> <span class="nx">perform_attach_to</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">,</span> <span class="nx">out</span> <span class="nb">Object</span><span class="o">?</span> <span class="nx">transport</span><span class="p">)</span> <span class="kr">throws</span> <span class="nb">Error</span><span class="p">,</span> <span class="nx">IOError</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">PipeTransport</span><span class="p">.</span><span class="nx">set_temp_directory</span> <span class="p">(</span><span class="nx">tempdir</span><span class="p">.</span><span class="nx">path</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">t</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">PipeTransport</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">stream_request</span> <span class="o">=</span> <span class="nx">Pipe</span><span class="p">.</span><span class="nx">open</span> <span class="p">(</span><span class="nx">t</span><span class="p">.</span><span class="nx">local_address</span><span class="p">,</span> <span class="nx">cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">uint</span> <span class="nx">id</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="nx">string</span> <span class="nx">entrypoint</span> <span class="o">=</span> <span class="s2">&#34;frida_agent_main&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="nx">string</span> <span class="nx">agent_parameters</span> <span class="o">=</span> <span class="nx">make_agent_parameters</span> <span class="p">(</span><span class="nx">t</span><span class="p">.</span><span class="nx">remote_address</span><span class="p">,</span> <span class="nx">options</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">linjector</span> <span class="o">=</span> <span class="nx">injector</span> <span class="nx">as</span> <span class="nx">Linjector</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="err">#</span><span class="k">if</span> <span class="nx">HAVE_EMBEDDED_ASSETS</span>
</span></span><span class="line"><span class="cl">    <span class="nx">id</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">linjector</span><span class="p">.</span><span class="nx">inject_library_resource</span> <span class="p">(</span><span class="nx">pid</span><span class="p">,</span> <span class="nx">agent</span><span class="p">,</span> <span class="nx">entrypoint</span><span class="p">,</span> <span class="nx">agent_parameters</span><span class="p">,</span> <span class="nx">cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="err">#</span><span class="k">else</span>
</span></span><span class="line"><span class="cl">    <span class="nx">id</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">linjector</span><span class="p">.</span><span class="nx">inject_library_file</span> <span class="p">(</span><span class="nx">pid</span><span class="p">,</span> <span class="nx">Config</span><span class="p">.</span><span class="nx">FRIDA_AGENT_PATH</span><span class="p">,</span> <span class="nx">entrypoint</span><span class="p">,</span> <span class="nx">agent_parameters</span><span class="p">,</span> <span class="nx">cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="err">#</span><span class="nx">endif</span>
</span></span><span class="line"><span class="cl">    <span class="nx">injectee_by_pid</span><span class="p">[</span><span class="nx">pid</span><span class="p">]</span> <span class="o">=</span> <span class="nx">id</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">transport</span> <span class="o">=</span> <span class="nx">t</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="nx">stream_request</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>确实是使用了 <code>inject_library_xxx</code> 的方式，<code>HAVE_EMBEDDED_ASSETS</code> 为真时使用的是从自身代码中释放出来的 agent 库，位置在:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-9" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">agent</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">AgentDescriptor</span> <span class="p">(</span><span class="nx">PathTemplate</span> <span class="p">(</span><span class="s2">&#34;frida-agent-&lt;arch&gt;.so&#34;</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">    <span class="k">new</span> <span class="nx">Bytes</span><span class="p">.</span><span class="kr">static</span> <span class="p">(</span><span class="nx">blob32</span><span class="p">.</span><span class="nx">data</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">    <span class="k">new</span> <span class="nx">Bytes</span><span class="p">.</span><span class="kr">static</span> <span class="p">(</span><span class="nx">blob64</span><span class="p">.</span><span class="nx">data</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">    <span class="k">new</span> <span class="nx">AgentResource</span><span class="p">[]</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">new</span> <span class="nx">AgentResource</span> <span class="p">(</span><span class="s2">&#34;frida-agent-arm.so&#34;</span><span class="p">,</span> <span class="k">new</span> <span class="nx">Bytes</span><span class="p">.</span><span class="kr">static</span> <span class="p">(</span><span class="nx">emulated_arm</span><span class="p">.</span><span class="nx">data</span><span class="p">),</span> <span class="nx">tempdir</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">        <span class="k">new</span> <span class="nx">AgentResource</span> <span class="p">(</span><span class="s2">&#34;frida-agent-arm64.so&#34;</span><span class="p">,</span> <span class="k">new</span> <span class="nx">Bytes</span><span class="p">.</span><span class="kr">static</span> <span class="p">(</span><span class="nx">emulated_arm64</span><span class="p">.</span><span class="nx">data</span><span class="p">),</span> <span class="nx">tempdir</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="nx">AgentMode</span><span class="p">.</span><span class="nx">INSTANCED</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">tempdir</span><span class="p">);</span></span></span></code></pre>
</div>
<p>这也是 Android 平台中 frida-server 的默认实现。</p>
<p><code>Linjector</code> 定义在 <em>src/linux/linjector.vala</em> ，即 Linux 平台上通用的进程注入实现，调用链路为:</p>
<ul>
<li>inject_library_resource</li>
<li>inject_library_file_with_template</li>
<li>helper.inject_library_file</li>
<li>helper.<code>_do_inject</code> (<em>src/linux/frida-helper-backend.vala</em>)</li>
</ul>
<p><code>_do_inject</code> 不使用 vala 而是直接使用 C 实现，代码在 <em>src/linux/frida-helper-backend-glue.c</em> :</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-10" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span>
</span></span><span class="line"><span class="cl"><span class="nf">_frida_linux_helper_backend_do_inject</span> <span class="p">(</span><span class="n">FridaLinuxHelperBackend</span> <span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="n">guint</span> <span class="n">pid</span><span class="p">,</span> <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">path</span><span class="p">,</span> <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">entrypoint</span><span class="p">,</span> <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">data</span><span class="p">,</span> <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">temp_path</span><span class="p">,</span> <span class="n">guint</span> <span class="n">id</span><span class="p">,</span> <span class="n">GError</span> <span class="o">**</span> <span class="n">error</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">open_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_libc_function</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="s">&#34;open&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">close_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_libc_function</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="s">&#34;close&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">write_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_libc_function</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="s">&#34;write&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">syscall_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_libc_function</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="s">&#34;syscall&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="cp">#if defined (HAVE_GLIBC)
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="cp">#elif defined (HAVE_UCLIBC)
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="cp">#elif defined (HAVE_ANDROID)
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>  <span class="n">params</span><span class="p">.</span><span class="n">dlopen_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_android_dlopen</span> <span class="p">(</span><span class="n">pid</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">dlopen_flags</span> <span class="o">=</span> <span class="n">RTLD_LAZY</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">dlclose_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_linker_address</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="n">dlclose</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="n">params</span><span class="p">.</span><span class="n">dlsym_impl</span> <span class="o">=</span> <span class="nf">frida_resolve_linker_address</span> <span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="n">dlsym</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="cp">#endif
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>
</span></span><span class="line"><span class="cl">  <span class="n">instance</span> <span class="o">=</span> <span class="nf">frida_inject_instance_new</span> <span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">id</span><span class="p">,</span> <span class="n">pid</span><span class="p">,</span> <span class="n">temp_path</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nf">frida_inject_instance_attach</span> <span class="p">(</span><span class="n">instance</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">saved_regs</span><span class="p">,</span> <span class="n">error</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="nf">frida_inject_instance_start_remote_thread</span> <span class="p">(</span><span class="n">instance</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">exited</span><span class="p">,</span> <span class="n">error</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="nf">frida_inject_instance_detach</span> <span class="p">(</span><span class="n">instance</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">saved_regs</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p><code>frida_inject_instance_attach</code> 中定义了真正的 attach 实现:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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      class="
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          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
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          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
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      <button 
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        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
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    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-11" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="n">gboolean</span>
</span></span><span class="line"><span class="cl"><span class="nf">frida_inject_instance_attach</span> <span class="p">(</span><span class="n">FridaInjectInstance</span> <span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="n">FridaRegs</span> <span class="o">*</span> <span class="n">saved_regs</span><span class="p">,</span> <span class="n">GError</span> <span class="o">**</span> <span class="n">error</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="kt">pid_t</span> <span class="n">pid</span> <span class="o">=</span> <span class="n">self</span><span class="o">-&gt;</span><span class="n">pid</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="n">can_seize</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">ret</span> <span class="o">=</span> <span class="nf">ptrace</span> <span class="p">(</span><span class="n">PTRACE_SEIZE</span><span class="p">,</span> <span class="n">pid</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="n">PTRACE_O_TRACEEXEC</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="k">else</span>
</span></span><span class="line"><span class="cl">    <span class="n">ret</span> <span class="o">=</span> <span class="nf">ptrace</span> <span class="p">(</span><span class="n">PTRACE_ATTACH</span><span class="p">,</span> <span class="n">pid</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>因此我们可以得出结论，<strong>frida 的进程注入是通过 ptrace 实现的</strong>，注入之后会在远端进程分配一段内存将 agent 拷贝过去并在目标进程中执行代码，<strong>执行完成后会 detach 目标进程</strong>。</p>
<p>这也是为什么在 frida 先连接上目标进程后还可以用 gdb 等调试器连接，而先 gdb 连接进程后 frida 就无法再次连上的原因。</p>
<p><code>frida-agent</code> 注入到目标进程并启动后会启动一个新进程与 host 进行通信，从而 host 可以给目标进行发送命令，比如执行代码，激活/关闭 hook，同时也能接收到目标进程的执行返回以及异步事件信息等。</p>
<h2 id="frida-agent" class="headerLink">
    <a href="#frida-agent" class="header-mark"></a>frida-agent</h2><p>在上节中调用 <code>inject_library</code> 指定了注入动态库后执行的的函数符号为 <code>frida_agent_main</code>，该函数也是由 vala 生成而来，源文件定义在 <em>lib/agent/agent.vala</em> 中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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    <button 
      class="
        code-block-button
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
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        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
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          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-12" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">namespace</span> <span class="nx">Frida</span><span class="p">.</span><span class="nx">Agent</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="k">void</span> <span class="nx">main</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">agent_parameters</span><span class="p">,</span> <span class="nx">ref</span> <span class="nx">Frida</span><span class="p">.</span><span class="nx">UnloadPolicy</span> <span class="nx">unload_policy</span><span class="p">,</span> <span class="k">void</span> <span class="o">*</span> <span class="nx">injector_state</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="nx">Runner</span><span class="p">.</span><span class="nx">shared_instance</span> <span class="o">==</span> <span class="kc">null</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">            <span class="nx">Runner</span><span class="p">.</span><span class="nx">create_and_run</span> <span class="p">(</span><span class="nx">agent_parameters</span><span class="p">,</span> <span class="nx">ref</span> <span class="nx">unload_policy</span><span class="p">,</span> <span class="nx">injector_state</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">else</span>
</span></span><span class="line"><span class="cl">            <span class="nx">Runner</span><span class="p">.</span><span class="nx">resume_after_transition</span> <span class="p">(</span><span class="nx">ref</span> <span class="nx">unload_policy</span><span class="p">,</span> <span class="nx">injector_state</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span></code></pre>
</div>
<p>关键的调用路径如下:</p>
<ul>
<li>Runner.create_and_run</li>
<li>new Runner (&hellip;)</li>
<li>shared_instance.run</li>
<li>Runner.run</li>
<li>Runner.start</li>
</ul>
<p>其中 <code>Runner.run</code> 函数在调用完 <code>start</code> 后会进入 <code>main_loop</code> 循环，直至进程退出或者收到 server 的解除命令。</p>
<p><code>Runner.start</code> 的作用是准备 Interceptor 以及 GumJS 的 ScriptBackend，并连接到启动时指定的 <code>transport_uri</code> 建立通信隧道。</p>
<h2 id="system_server" class="headerLink">
    <a href="#system_server" class="header-mark"></a>system_server</h2><p>另外一个我觉得比较有意思的是 frida-server 中除了注入到目标进程的 agent，还有一个 agent，即 <code>system_server_agent</code>。</p>
<p>用过 <code>frida-tools</code> 的朋友应该都知道其中有个 <code>frida-ps</code> 命令，可以查看设备中的应用名称、包名甚至是 Icon，也可以查看当前运行在窗口顶部的应用。之前一直以为是通过 <code>pm list packages</code> 和 <code>dumpsys</code> 等命令实现的，看过代码之后才发现原来 frida-server 还对 <code>system_server</code> 进程进行了注入，并且所使用的 agent 就是 <code>system_server_agent</code>。</p>
<p>如果不了解 <code>system_server</code>，可以先回顾一下笔者之前的文章 &ldquo;<a href="https://evilpan.com/2020/11/08/android-init/" target="_blank" rel="noopener noreferrer">Android 用户态启动流程分析</a>&quot;，其中提到在 Android 系统启动时，zygote 启动的第一个进程就是 <code>system_server</code>，这也是系统中第一个启动的 Java 进程，其中包含了 <code>ActivityManagerService</code>、 <code>PackageManagerService</code> 等系统服务。frida-server 对其进行注入，一方面是为了获取系统中的应用信息，另一方面也是为了可以实现 <code>spawn</code> 方式启动应用的功能。</p>
<p>以获取当前窗口中展示在最上层的应用功能为例，接口为 <code>get_frontmost_application</code>，最终的实现在 <code>SystemServerAgent</code>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-13" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">async</span> <span class="nx">HostApplicationInfo</span> <span class="nx">get_frontmost_application</span> <span class="p">(</span><span class="nx">FrontmostQueryOptions</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nb">Error</span><span class="p">,</span> <span class="nx">IOError</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">scope</span> <span class="o">=</span> <span class="nx">options</span><span class="p">.</span><span class="nx">scope</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">scope_node</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">Json</span><span class="p">.</span><span class="nx">Node</span><span class="p">.</span><span class="nx">alloc</span> <span class="p">().</span><span class="nx">init_string</span> <span class="p">(</span><span class="nx">scope</span><span class="p">.</span><span class="nx">to_nick</span> <span class="p">());</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">Json</span><span class="p">.</span><span class="nx">Node</span> <span class="nx">result</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">call</span> <span class="p">(</span><span class="s2">&#34;getFrontmostApplication&#34;</span><span class="p">,</span> <span class="k">new</span> <span class="nx">Json</span><span class="p">.</span><span class="nx">Node</span><span class="p">[]</span> <span class="p">{</span> <span class="nx">scope_node</span> <span class="p">},</span> <span class="nx">cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>这实际上是调用了 <em>src/linux/agent/system-server.js</em> 中导出的方法:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-14" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">rpc</span><span class="p">.</span><span class="nx">exports</span> <span class="o">=</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">getFrontmostApplication</span><span class="p">(</span><span class="nx">scope</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="nx">performOnJavaVM</span><span class="p">(()</span> <span class="p">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">pkgName</span> <span class="o">=</span> <span class="nx">getFrontmostPackageName</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">      <span class="k">if</span> <span class="p">(</span><span class="nx">pkgName</span> <span class="o">===</span> <span class="kc">null</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">appInfo</span> <span class="o">=</span> <span class="nx">packageManager</span><span class="p">.</span><span class="nx">getApplicationInfo</span><span class="p">(</span><span class="nx">pkgName</span><span class="p">,</span> <span class="mi">0</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">appLabel</span> <span class="o">=</span> <span class="nx">loadAppLabel</span><span class="p">.</span><span class="nx">call</span><span class="p">(</span><span class="nx">appInfo</span><span class="p">,</span> <span class="nx">packageManager</span><span class="p">).</span><span class="nx">toString</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">pid</span> <span class="o">=</span> <span class="nx">computeAppPids</span><span class="p">(</span><span class="nx">getAppProcesses</span><span class="p">()).</span><span class="nx">get</span><span class="p">(</span><span class="nx">pkgName</span><span class="p">)</span> <span class="o">??</span> <span class="mi">0</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">parameters</span> <span class="o">=</span> <span class="p">(</span><span class="nx">scope</span> <span class="o">!==</span> <span class="s1">&#39;minimal&#39;</span><span class="p">)</span> <span class="o">?</span> <span class="nx">fetchAppParameters</span><span class="p">(</span><span class="nx">pkgName</span><span class="p">,</span> <span class="nx">appInfo</span><span class="p">,</span> <span class="nx">scope</span><span class="p">)</span> <span class="o">:</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="k">return</span> <span class="p">[</span><span class="nx">pkgName</span><span class="p">,</span> <span class="nx">appLabel</span><span class="p">,</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">parameters</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">    <span class="p">});</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>这部分 JS 代码也是内置到 frida-server 中的，基于 gum-js 实现了对 <code>system_server</code> 的 Java 代码调用和劫持功能。</p>
<h1 id="frida-gadget" class="headerLink">
    <a href="#frida-gadget" class="header-mark"></a>frida-gadget</h1><p>除了 <code>frida-server</code>，另外一个比较常用的模块就是 <a href="https://frida.re/docs/gadget/" target="_blank" rel="noopener noreferrer">frida-gadget</a> 了。攻击者可以通过重打包修改动态库的依赖或者修改 smali 代码去实现向三方应用注入 gadget，当然也可以通过任意其他加载动态库的方式。</p>
<p>gadget 本身是一个动态库，在加载到目标进程中后会马上触发 ctor 执行指定代码，默认情况下是挂起当前进程并监听在 27042 端口等待 Host 的连接并恢复运行。其文件路径为 <em>lib/gadget/gadget.vala</em> ，启动入口为 <code>Frida.Gadget.load</code>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-15" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">public</span> <span class="k">void</span> <span class="nx">load</span> <span class="p">(</span><span class="nx">Gum</span><span class="p">.</span><span class="nx">MemoryRange</span><span class="o">?</span> <span class="nx">mapped_range</span><span class="p">,</span> <span class="nx">string</span><span class="o">?</span> <span class="nx">config_data</span><span class="p">,</span> <span class="kr">int</span> <span class="o">*</span> <span class="nx">result</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">location</span> <span class="o">=</span> <span class="nx">detect_location</span> <span class="p">(</span><span class="nx">mapped_range</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nx">config</span> <span class="o">=</span> <span class="p">(</span><span class="nx">config_data</span> <span class="o">!=</span> <span class="kc">null</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">                <span class="o">?</span> <span class="nx">parse_config</span> <span class="p">(</span><span class="nx">config_data</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">                <span class="o">:</span> <span class="nx">load_config</span> <span class="p">(</span><span class="nx">location</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">Gum</span><span class="p">.</span><span class="nx">Cloak</span><span class="p">.</span><span class="nx">add_range</span> <span class="p">(</span><span class="nx">location</span><span class="p">.</span><span class="nx">range</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">interceptor</span> <span class="o">=</span> <span class="nx">Gum</span><span class="p">.</span><span class="nx">Interceptor</span><span class="p">.</span><span class="nx">obtain</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="nx">interceptor</span><span class="p">.</span><span class="nx">begin_transaction</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="nx">exceptor</span> <span class="o">=</span> <span class="nx">Gum</span><span class="p">.</span><span class="nx">Exceptor</span><span class="p">.</span><span class="nx">obtain</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// try-catch
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kd">var</span> <span class="nx">interaction</span> <span class="o">=</span> <span class="nx">config</span><span class="p">.</span><span class="nx">interaction</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="nx">interaction</span> <span class="nx">is</span> <span class="nx">ScriptInteraction</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">controller</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ScriptRunner</span> <span class="p">(</span><span class="nx">config</span><span class="p">,</span> <span class="nx">location</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="nx">interaction</span> <span class="nx">is</span> <span class="nx">ScriptDirectoryInteraction</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">controller</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ScriptDirectoryRunner</span> <span class="p">(</span><span class="nx">config</span><span class="p">,</span> <span class="nx">location</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="nx">interaction</span> <span class="nx">is</span> <span class="nx">ListenInteraction</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">controller</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ControlServer</span> <span class="p">(</span><span class="nx">config</span><span class="p">,</span> <span class="nx">location</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="nx">interaction</span> <span class="nx">is</span> <span class="nx">ConnectInteraction</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">controller</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ClusterClient</span> <span class="p">(</span><span class="nx">config</span><span class="p">,</span> <span class="nx">location</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// throw &#34;Invalid interaction specified&#34;
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="nx">interceptor</span><span class="p">.</span><span class="nx">end_transaction</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">wait_for_resume_needed</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="nx">resume</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ..
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">start</span> <span class="p">(</span><span class="nx">request</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>正如文档中所说，Gadget 启动时会去指定路径搜索配置文件，并根据其设置进入不同的运行模式，默认的配置文件如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-16" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="s2">&#34;interaction&#34;</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;type&#34;</span><span class="o">:</span> <span class="s2">&#34;listen&#34;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;address&#34;</span><span class="o">:</span> <span class="s2">&#34;127.0.0.1&#34;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;port&#34;</span><span class="o">:</span> <span class="mi">27042</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;on_port_conflict&#34;</span><span class="o">:</span> <span class="s2">&#34;fail&#34;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;on_load&#34;</span><span class="o">:</span> <span class="s2">&#34;wait&#34;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>即使用 <code>listen</code> 模式，监听在 27042 端口并等待连接。除了 listen 以外，还支持以下几种模式:</p>
<ul>
<li><strong>connect</strong>: Gadget 启动后主动连接到指定地址;</li>
<li><strong>script</strong>: 启动后直接加载指定的 JavaScript 文件；</li>
<li><strong>script-directory</strong>: 启动后加载指定目录下的所有 JavaScript 文件；</li>
</ul>
<p>值得一提的是，<code>script-directory</code> 模式可以用来实现系统级别的插件功能，比如在指定目录中编写一个 <code>twitter.js</code>，用于实现针对 Twitter 的 Hook 功能，比如自定义过滤、自动点赞等等；另外写一个 <code>twitter.config</code> 来过滤应用:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
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          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-17" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="s2">&#34;filter&#34;</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;executables&#34;</span><span class="o">:</span> <span class="p">[</span><span class="s2">&#34;Twitter&#34;</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;bundles&#34;</span><span class="o">:</span> <span class="p">[</span><span class="s2">&#34;com.twitter.twitter-mac&#34;</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">    <span class="s2">&#34;objc_classes&#34;</span><span class="o">:</span> <span class="p">[</span><span class="s2">&#34;Twitter&#34;</span><span class="p">]</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>这样就只有满足指定条件的进程才会加载 <code>twitter.js</code> 脚本，从而实现特定应用的持久化 Hook 功能。熟悉 Xposed 或者 Tweak 开发的应该都知道这意味着什么。</p>
<h1 id="ipc-通信" class="headerLink">
    <a href="#ipc-%e9%80%9a%e4%bf%a1" class="header-mark"></a>IPC 通信</h1><p>在 frida-core 中有许多需要进程间通信的行为，比如 frida-server 需要与注入到目标进程中的 agent 进行通信，通知目标进程开启或者关闭 Interceptor；agent 同样也需要与 host 进行通信，在 gum-js 中将 <code>console.log</code> 或者 <code>send</code> 的消息发给 host，或者接收一些异步的应用退出和异常事件等。而其中这些进程间的交互都是通过 <a href="https://en.wikipedia.org/wiki/D-Bus" target="_blank" rel="noopener noreferrer">D-Bus</a> 去实现的。</p>
<p><code>D-Bus</code> 是一种基于消息的进程间通信机制，全称为 Desktop Bus，最初从 FreeDesktop 中的模块独立出来。其主要作用是提供在 Linux 操作系统桌面环境中的组件通信，比如 GNOME 或 KDE。D-Bus 使用 C 语言开发，提供了 GLib、Qt、Python 等编程接口，在 frida-core 中主要使用其 Vala 接口进行集成。</p>
<p>下面从实际代码看一个 D-Bus Vala 接口实现的 C/S 通信示例。 首先是服务端，定义一个 <code>DemoServer</code>， 内部定义了四个方法:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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      <button 
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
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          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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        class="
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-18" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
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      "><span class="line"><span class="cl"><span class="p">[</span><span class="nx">DBus</span> <span class="p">(</span><span class="nx">name</span> <span class="o">=</span> <span class="s2">&#34;org.example.Demo&#34;</span><span class="p">)]</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="kr">class</span> <span class="nx">DemoServer</span> <span class="o">:</span> <span class="nb">Object</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">private</span> <span class="kr">int</span> <span class="nx">counter</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">int</span> <span class="nx">ping</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%s\n&#34;</span><span class="p">,</span> <span class="nx">msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nx">counter</span><span class="o">++</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">int</span> <span class="nx">ping_with_signal</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%s\n&#34;</span><span class="p">,</span> <span class="nx">msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">pong</span><span class="p">(</span><span class="nx">counter</span><span class="p">,</span> <span class="nx">msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nx">counter</span><span class="o">++</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="cm">/* Including any parameter of type GLib.BusName won&#39;t be added to the
</span></span></span><span class="line"><span class="cl"><span class="cm">       interface and will return the dbus sender name (who is calling the method) */</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">int</span> <span class="nx">ping_with_sender</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">,</span> <span class="nx">GLib</span><span class="p">.</span><span class="nx">BusName</span> <span class="nx">sender</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%s, from: %s\n&#34;</span><span class="p">,</span> <span class="nx">msg</span><span class="p">,</span> <span class="nx">sender</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nx">counter</span><span class="o">++</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="k">void</span> <span class="nx">ping_error</span> <span class="p">()</span> <span class="kr">throws</span> <span class="nb">Error</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">throw</span> <span class="k">new</span> <span class="nx">DemoError</span><span class="p">.</span><span class="nx">SOME_ERROR</span> <span class="p">(</span><span class="s2">&#34;There was an error!&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">pong</span> <span class="p">(</span><span class="kr">int</span> <span class="nx">count</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="p">[</span><span class="nx">DBus</span> <span class="p">(</span><span class="nx">name</span> <span class="o">=</span> <span class="s2">&#34;org.example.DemoError&#34;</span><span class="p">)]</span>
</span></span><span class="line"><span class="cl"><span class="kr">public</span> <span class="nx">errordomain</span> <span class="nx">DemoError</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">SOME_ERROR</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">void</span> <span class="nx">on_bus_aquired</span> <span class="p">(</span><span class="nx">DBusConnection</span> <span class="nx">conn</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">conn</span><span class="p">.</span><span class="nx">register_object</span> <span class="p">(</span><span class="s2">&#34;/org/example/demo&#34;</span><span class="p">,</span> <span class="k">new</span> <span class="nx">DemoServer</span> <span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="nx">IOError</span> <span class="nx">e</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stderr</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;Could not register service\n&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">void</span> <span class="nx">main</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Bus</span><span class="p">.</span><span class="nx">own_name</span> <span class="p">(</span><span class="nx">BusType</span><span class="p">.</span><span class="nx">SESSION</span><span class="p">,</span> <span class="s2">&#34;org.example.Demo&#34;</span><span class="p">,</span> <span class="nx">BusNameOwnerFlags</span><span class="p">.</span><span class="nx">NONE</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                  <span class="nx">on_bus_aquired</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                  <span class="p">()</span> <span class="p">=&gt;</span> <span class="p">{},</span>
</span></span><span class="line"><span class="cl">                  <span class="p">()</span> <span class="p">=&gt;</span> <span class="nx">stderr</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;Could not aquire name\n&#34;</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">new</span> <span class="nx">MainLoop</span> <span class="p">().</span><span class="nx">run</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中使用 <code>Bus.own_name</code> 去连接总线 <code>org.example.Demo</code>，连接成功后注册了名为 <code>/org/example/demo</code> 的服务。客户端可以通过连接同样的总线和服务去获取到对应的远程对象接口，从而在本地实现远程调用。客户端示例如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-19" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="p">[</span><span class="nx">DBus</span> <span class="p">(</span><span class="nx">name</span> <span class="o">=</span> <span class="s2">&#34;org.example.Demo&#34;</span><span class="p">)]</span>
</span></span><span class="line"><span class="cl"><span class="kr">interface</span> <span class="nx">Demo</span> <span class="o">:</span> <span class="nb">Object</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">int</span> <span class="nx">ping</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">IOError</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">int</span> <span class="nx">ping_with_sender</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">IOError</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="kr">abstract</span> <span class="kr">int</span> <span class="nx">ping_with_signal</span> <span class="p">(</span><span class="nx">string</span> <span class="nx">msg</span><span class="p">)</span> <span class="kr">throws</span> <span class="nx">IOError</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kr">public</span> <span class="nx">signal</span> <span class="k">void</span> <span class="nx">pong</span> <span class="p">(</span><span class="kr">int</span> <span class="nx">count</span><span class="p">,</span> <span class="nx">string</span> <span class="nx">msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">void</span> <span class="nx">main</span> <span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="cm">/* Needed only if your client is listening to signals; you can omit it otherwise */</span>
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">loop</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">MainLoop</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="cm">/* Important: keep demo variable out of try/catch scope not lose signals! */</span>
</span></span><span class="line"><span class="cl">    <span class="nx">Demo</span> <span class="nx">demo</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">demo</span> <span class="o">=</span> <span class="nx">Bus</span><span class="p">.</span><span class="nx">get_proxy_sync</span> <span class="p">(</span><span class="nx">BusType</span><span class="p">.</span><span class="nx">SESSION</span><span class="p">,</span> <span class="s2">&#34;org.example.Demo&#34;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                    <span class="s2">&#34;/org/example/demo&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="cm">/* Connecting to signal pong! */</span>
</span></span><span class="line"><span class="cl">        <span class="nx">demo</span><span class="p">.</span><span class="nx">pong</span><span class="p">.</span><span class="nx">connect</span><span class="p">((</span><span class="nx">c</span><span class="p">,</span> <span class="nx">m</span><span class="p">)</span> <span class="p">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;Got pong %d for msg &#39;%s&#39;\n&#34;</span><span class="p">,</span> <span class="nx">c</span><span class="p">,</span> <span class="nx">m</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="nx">loop</span><span class="p">.</span><span class="nx">quit</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">        <span class="p">});</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="kr">int</span> <span class="nx">reply</span> <span class="o">=</span> <span class="nx">demo</span><span class="p">.</span><span class="nx">ping</span> <span class="p">(</span><span class="s2">&#34;Hello from Vala&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%d\n&#34;</span><span class="p">,</span> <span class="nx">reply</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="nx">reply</span> <span class="o">=</span> <span class="nx">demo</span><span class="p">.</span><span class="nx">ping_with_sender</span> <span class="p">(</span><span class="s2">&#34;Hello from Vala with sender&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%d\n&#34;</span><span class="p">,</span> <span class="nx">reply</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="nx">reply</span> <span class="o">=</span> <span class="nx">demo</span><span class="p">.</span><span class="nx">ping_with_signal</span> <span class="p">(</span><span class="s2">&#34;Hello from Vala with signal&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stdout</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%d\n&#34;</span><span class="p">,</span> <span class="nx">reply</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="nx">IOError</span> <span class="nx">e</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stderr</span><span class="p">.</span><span class="nx">printf</span> <span class="p">(</span><span class="s2">&#34;%s\n&#34;</span><span class="p">,</span> <span class="nx">e</span><span class="p">.</span><span class="nx">message</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="nx">loop</span><span class="p">.</span><span class="nx">run</span><span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>客户端中需要定义与远程对象一致的 <code>interface</code>，并通过 <code>get_proxy</code> 请求获得远程对象的本地代理，从而实现透明的远程调用。注意的是编译需要添加对应的库:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-20" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ valac --pkg gio-2.0 demo-server.vala
</span></span><span class="line"><span class="cl">$ valac --pkg gio-2.0 demo-client.vala</span></span></code></pre>
</div>
<p>从效果上看有点类似于 Android 的 binder 通信机制。但是 D-Bus 是一种更加上层的封装，在不同操作系统上可以使用不同的底层实现。在 Linxu 操作系统中通常是基于 UNIX socket 实现的多进程通信，当然也可以修改配置去通过 TCP socket 去实现。</p>
<p>frida 执行进程注入时同时也实现了 IPC 相关的初始化，在 <em>src/host-session-service.vala</em> 中可以看到关键代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-21" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">private</span> <span class="kr">async</span> <span class="nx">AgentEntry</span> <span class="nx">establish</span> <span class="p">(</span><span class="nx">uint</span> <span class="nx">pid</span><span class="p">,</span> <span class="nx">HashTable</span><span class="o">&lt;</span><span class="nx">string</span><span class="p">,</span> <span class="nx">Variant</span><span class="o">&gt;</span> <span class="nx">options</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">Cancellable</span><span class="o">?</span> <span class="nx">cancellable</span><span class="p">)</span> <span class="kr">throws</span> <span class="nb">Error</span><span class="p">,</span> <span class="nx">IOError</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">DBusConnection</span> <span class="nx">connection</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kd">var</span> <span class="nx">stream_request</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">perform_attach_to</span> <span class="p">(</span><span class="nx">pid</span><span class="p">,</span> <span class="nx">options</span><span class="p">,</span> <span class="nx">io_cancellable</span><span class="p">,</span> <span class="nx">out</span> <span class="nx">transport</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nx">IOStream</span> <span class="nx">stream</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">stream_request</span><span class="p">.</span><span class="nx">wait_async</span> <span class="p">(</span><span class="nx">io_cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">connection</span> <span class="o">=</span> <span class="k">yield</span> <span class="k">new</span> <span class="nx">DBusConnection</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="nx">stream</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">ServerGuid</span><span class="p">.</span><span class="nx">HOST_SESSION_SERVICE</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">AUTHENTICATION_SERVER</span> <span class="o">|</span> <span class="nx">AUTHENTICATION_ALLOW_ANONYMOUS</span> <span class="o">|</span> <span class="nx">DELAY_MESSAGE_PROCESSING</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="kc">null</span><span class="p">,</span> <span class="nx">io_cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nx">controller_registration_id</span> <span class="o">=</span> <span class="nx">connection</span><span class="p">.</span><span class="nx">register_object</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="nx">ObjectPath</span><span class="p">.</span><span class="nx">AGENT_CONTROLLER</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="p">(</span><span class="nx">AgentController</span><span class="p">)</span> <span class="k">this</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nx">connection</span><span class="p">.</span><span class="nx">start_message_processing</span> <span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="nx">provider</span> <span class="o">=</span> <span class="k">yield</span> <span class="nx">connection</span><span class="p">.</span><span class="nx">get_proxy</span> <span class="p">(</span><span class="kc">null</span><span class="p">,</span> <span class="nx">ObjectPath</span><span class="p">.</span><span class="nx">AGENT_SESSION_PROVIDER</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">DO_NOT_LOAD_PROPERTIES</span><span class="p">,</span> <span class="nx">io_cancellable</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>这里使用了 <code>DBusConnection</code> 来连接总线，效果和 <code>own_name</code> 是类似的。其中总线的名称为 <code>ServerGuid.HOST_SESSION_SERVICE</code>，所注册的 RPC 服务名称为 <code>ObjectPath.AGENT_CONTROLLER</code>。另外这里还通过总线去获取了一个远程对象 <code>ObjectPath.AGENT_SESSION_PROVIDER</code>，用以实现透明的远程调用。这些服务的名称都定义在 <em>lib/base/session.vala</em> 文件中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-22" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
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      "><span class="line"><span class="cl"><span class="nx">namespace</span> <span class="nx">Frida</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">namespace</span> <span class="nx">ServerGuid</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">HOST_SESSION_SERVICE</span> <span class="o">=</span> <span class="s2">&#34;6769746875622e636f6d2f6672696461&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">namespace</span> <span class="nx">ObjectPath</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">HOST_SESSION</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/HostSession&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">AGENT_SESSION_PROVIDER</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/AgentSessionProvider&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">AGENT_SESSION</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/AgentSession&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">AGENT_CONTROLLER</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/AgentController&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">AGENT_MESSAGE_SINK</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/AgentMessageSink&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">CHILD_SESSION</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/ChildSession&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">TRANSPORT_BROKER</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/TransportBroker&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">PORTAL_SESSION</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/PortalSession&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">BUS_SESSION</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/BusSession&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">public</span> <span class="kr">const</span> <span class="nx">string</span> <span class="nx">AUTHENTICATION_SERVICE</span> <span class="o">=</span> <span class="s2">&#34;/re/frida/AuthenticationService&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>通过搜索 <code>[DBus (name = &quot;xxx&quot;)]</code> 可以看到 frida-core 中定义的所有 IPC 服务，感兴趣的可以有针对性地去进行深入分析。</p>
<p>拓展阅读:</p>
<ul>
<li><a href="https://dbus.freedesktop.org/doc/dbus-tutorial.html" target="_blank" rel="noopener noreferrer">https://dbus.freedesktop.org/doc/dbus-tutorial.html</a></li>
<li><a href="https://wiki.gnome.org/Projects/Vala/DBusServerSample" target="_blank" rel="noopener noreferrer">https://wiki.gnome.org/Projects/Vala/DBusServerSample</a></li>
<li><a href="https://www.reddit.com/r/commandline/comments/13o581/dbus_vs_unix_sockets/" target="_blank" rel="noopener noreferrer">https://www.reddit.com/r/commandline/comments/13o581/dbus_vs_unix_sockets/</a></li>
</ul>
<h1 id="selinux" class="headerLink">
    <a href="#selinux" class="header-mark"></a>SELinux</h1><p>在 <a href="https://evilpan.com/2020/12/06/android-rooting/#selinux" target="_blank" rel="noopener noreferrer">Android/Linux Root 的那些事儿</a> 中曾经介绍过 Android 系统的安全访问控制体系，不是简单的 <code>uid=0</code> 就可以为所欲为的。frida 这种又注入进程又各种进程间通信的，显然违反了 SELinux 的默认规则，那么它是如何实现的呢？其实说起来也很简单，就是对当前系统的 SELinux 规则进行了 patch，本节就来分析下其具体是如何做的。</p>
<p>patch 的代码主要集中在 <em>lib/selinux/patch.c</em> 文件中，代码就不贴了，主要流程可以简单描述如下:</p>
<ol>
<li>从 <em>/sys/fs/selinux/policy</em> 文件中加载当前系统的 SELinux policy；</li>
<li>在当前 sepolicy 中增加新的 SELinux 文件类型 <code>frida_file</code>；</li>
<li>依次插入新的 SELinux 规则(见后文)；</li>
<li>通过写入 <em>/sys/fs/selinux/load</em> 文件保存修改后的 sepolicy；</li>
<li>(可选) 如果上述保存操作失败，就先临时将 SELinux 设置为 permissive 然后再保存一次，保存成功后重新恢复为 enforcing；</li>
</ol>
<p>第 3 步中插入的 SELinux 规则如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-23" 
    class="
      chroma 
      !tw-block 
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      "><span class="line"><span class="cl"><span class="k">typedef</span> <span class="k">struct</span> <span class="n">_FridaSELinuxRule</span> <span class="n">FridaSELinuxRule</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="k">struct</span> <span class="n">_FridaSELinuxRule</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">sources</span><span class="p">[</span><span class="mi">4</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">target</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">klass</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="k">const</span> <span class="n">gchar</span> <span class="o">*</span> <span class="n">permissions</span><span class="p">[</span><span class="mi">16</span><span class="p">];</span>
</span></span><span class="line"><span class="cl"><span class="p">};</span>
</span></span><span class="line"><span class="cl"><span class="k">static</span> <span class="k">const</span> <span class="n">FridaSELinuxRule</span> <span class="n">frida_selinux_rules</span><span class="p">[]</span> <span class="o">=</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="s">&#34;process&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;execmem&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;frida_file&#34;</span><span class="p">,</span> <span class="s">&#34;dir&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;search&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;frida_file&#34;</span><span class="p">,</span> <span class="s">&#34;fifo_file&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;open&#34;</span><span class="p">,</span> <span class="s">&#34;write&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;frida_file&#34;</span><span class="p">,</span> <span class="s">&#34;file&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;open&#34;</span><span class="p">,</span> <span class="s">&#34;read&#34;</span><span class="p">,</span> <span class="s">&#34;getattr&#34;</span><span class="p">,</span> <span class="s">&#34;execute&#34;</span><span class="p">,</span> <span class="s">&#34;?map&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;frida_file&#34;</span><span class="p">,</span> <span class="s">&#34;sock_file&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;write&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;shell_data_file&#34;</span><span class="p">,</span> <span class="s">&#34;dir&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;search&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;zygote_exec&#34;</span><span class="p">,</span> <span class="s">&#34;file&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;execute&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;$self&#34;</span><span class="p">,</span> <span class="s">&#34;process&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;sigchld&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;$self&#34;</span><span class="p">,</span> <span class="s">&#34;fd&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;use&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;$self&#34;</span><span class="p">,</span> <span class="s">&#34;unix_stream_socket&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;connectto&#34;</span><span class="p">,</span> <span class="s">&#34;read&#34;</span><span class="p">,</span> <span class="s">&#34;write&#34;</span><span class="p">,</span> <span class="s">&#34;getattr&#34;</span><span class="p">,</span> <span class="s">&#34;getopt&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;domain&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;$self&#34;</span><span class="p">,</span> <span class="s">&#34;tcp_socket&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;read&#34;</span><span class="p">,</span> <span class="s">&#34;write&#34;</span><span class="p">,</span> <span class="s">&#34;getattr&#34;</span><span class="p">,</span> <span class="s">&#34;getopt&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;zygote&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;zygote&#34;</span><span class="p">,</span> <span class="s">&#34;capability&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;sys_ptrace&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">{</span> <span class="p">{</span> <span class="s">&#34;?app_zygote&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">},</span> <span class="s">&#34;zygote_exec&#34;</span><span class="p">,</span> <span class="s">&#34;file&#34;</span><span class="p">,</span> <span class="p">{</span> <span class="s">&#34;read&#34;</span><span class="p">,</span> <span class="nb">NULL</span> <span class="p">}</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl"><span class="p">};</span></span></span></code></pre>
</div>
<p>其中 <code>$self</code> 表示当前进程的 context，即 getcon 获取的值。在完成对 sepolicy 的动态修改后，frida 就可以正常的在 enforcing 的环境下运行了。</p>
<h1 id="后记" class="headerLink">
    <a href="#%e5%90%8e%e8%ae%b0" class="header-mark"></a>后记</h1><p><code>frida-core</code> 在 <code>gum-js</code> 的基础上实现了操作系统层面的主要功能，比如进程注入、进程间通信、系统信息采集、系统权限管理等功能。正是因为这些核心组件的加入，使得 frida 成为了一个上手简单却又功能强大的动态分析框架。另外由于这些核心组件大部分使用 Vala 语言编写，在保障内存安全性的同时也提供了丰富的跨平台能力，支持 Android、iOS、Linux、MacOS、Windows 这些主流操作系统的不同架构。虽然本文仅针对 Android/Linux 操作系统的主要组件进行了介绍，但相信从中也能看出 frida-core 项目本身的代码风格架构设计，对于其他组件或者其他操作系统上的实现也是大同小异的，后续遇到具体问题的时候再深入分析对应组件即可。</p>
<hr>
<blockquote>
  <p><strong>版权声明</strong>: 自由转载-非商用-非衍生-保持署名 (<a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noopener noreferrer">CC 4.0 BY-SA</a>)<br>
<strong>原文地址</strong>: <a href="https://evilpan.com/2022/04/09/frida-core/" target="_blank" rel="noopener noreferrer">https://evilpan.com/2022/04/09/frida-core/</a><br>
<strong>微信订阅</strong>: <strong>『<a href="http://t.evilpan.com/qrcode.jpg" target="_blank" rel="noopener noreferrer">有价值炮灰</a>』</strong><br>
&ndash; <em>TO BE CONTINUED</em>.</p>
</blockquote><hr>]]></description>
</item><item>
    <title>ART 在 Android 安全攻防中的应用</title>
    <link>https://evilpan.com/2021/12/26/art-internal/</link>
    <pubDate>Sun, 26 Dec 2021 12:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2021/12/26/art-internal/</guid>
    <description><![CDATA[<p>在日常的 Android 应用安全分析中，经常会遇到一些对抗，比如目标应用加壳、混淆、加固，需要进行脱壳还原；又或者会有针对常用注入工具的检测，比如 frida、Xposed 等，这时候也会想知道这些工具的核心原理以及是否自己可以实现。</p>
<p>其实这些问题的答案就在 Android 的 Java 虚拟机实现中。可以是早期的 Dalvik 虚拟机，也可以是最新的 ART 虚拟机。从时代潮流来看，本文主要专注于 ART。不过，为了铭记历史，也会对 Dalvik 虚拟机做一个简单的介绍。最后会从 ART 的实现出发j对一些实际的应用场景进行讨论。</p>
<blockquote>
  <p>注: 本文分析基于 AOSP android-12.0.0_r11</p>
</blockquote><h1 id="java-vm" class="headerLink">
    <a href="#java-vm" class="header-mark"></a>Java VM</h1><p>我们知道，Java 是一门跨平台的语言，系统实际运行的是 Java 字节码，由 Java 虚拟机去解释执行。如果读者之前看过 <a href="https://evilpan.com/2020/10/11/protected-python/" target="_blank" rel="noopener noreferrer">如何破解一个Python虚拟机壳并拿走12300元ETH</a> 一文或者对 Python 虚拟机有所了解的话就会知道，解释执行的过程可以看做是一个循环，对每条指令进行解析，并针对指令的名称通过巨大的 switch-case 分发到不同的分支中处理。其实 Java 虚拟机也是类似的，但 JVM 对于性能做了很多优化，比如 JIT 运行时将字节码优化成对应平台的二进制代码，提高后续运行速度等。</p>
<p>Android 代码既然是用 Java 代码编写的，那么运行时应该也会有一个解析字节码的虚拟机。和标准的 JVM 不同，Android 中实际会将 Java 代码编译为 Dalvik 字节码，运行时解析的也是用自研的虚拟机实现。之所以使用自研实现，也许一方面有商业版权的考虑，另一方面也确实是适应了移动端的的运行场景。Dalvik 指令基于寄存器，占 1-2 字节，Java 虚拟机指令基于栈，每条指令只占 1 字节；因此 Dalvik 虚拟机用空间换时间从而获得比 Oracle JVM 更快的执行速度。</p>
<h2 id="启动" class="headerLink">
    <a href="#%e5%90%af%e5%8a%a8" class="header-mark"></a>启动</h2><p>其实 Java 代码执行并不慢，但其启动时间却是一大瓶颈。如果每个 APP 运行都要启动并初始化 Java 虚拟机，那延时将是无法接受的。在 <a href="https://evilpan.com/2021/12/05/apk-startup/" target="_blank" rel="noopener noreferrer">Android 12 应用启动流程分析</a> 一文中我们说到，APP 应用进程实际上是通过 zygote 进程 fork 出来的。这样的好处是子进程继承了父进程的进程空间，对于只读部分可以直接使用，而数据段也可以通过 COW(Copy On Write) 进行延时映射。查看 zygote 与其子进程的 <code>/proc/self/maps</code> 可以发现大部分系统库的映射都是相同的，这就是 fork 所带来的好处。</p>
<p>在 <a href="https://evilpan.com/2020/11/08/android-init/#native-%E5%B1%82" target="_blank" rel="noopener noreferrer">Android 用户态启动流程分析</a> 中我们分析了 init、zygote 和 system_server 的启动流程，其中在介绍 zygote 的启动流程时说到这是个 native 程序，在其中 main 函数的结尾有这么一段代码:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-40" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
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</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">zygote</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">runtime</span><span class="p">.</span><span class="n">start</span><span class="p">(</span><span class="s">&#34;com.android.internal.os.ZygoteInit&#34;</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">zygote</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="n">className</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">runtime</span><span class="p">.</span><span class="n">start</span><span class="p">(</span><span class="s">&#34;com.android.internal.os.RuntimeInit&#34;</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">zygote</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">fprintf</span><span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&#34;Error: no class name or --zygote supplied.</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// ....
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>上述代码在 <strong>frameworks/base/cmds/app_process/app_main.cpp</strong> 中，<strong>runtime.start</strong> 的作用就是启动 Java 虚拟机并将执行流转交给对应的 Java 函数。</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-41" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
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      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">AndroidRuntime</span><span class="o">::</span><span class="n">start</span><span class="p">(</span><span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">className</span><span class="p">,</span> <span class="k">const</span> <span class="n">Vector</span><span class="o">&lt;</span><span class="n">String8</span><span class="o">&gt;&amp;</span> <span class="n">options</span><span class="p">,</span> <span class="kt">bool</span> <span class="n">zygote</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="cm">/* start the virtual machine */</span>
</span></span><span class="line"><span class="cl">    <span class="n">JniInvocation</span> <span class="n">jni_invocation</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">jni_invocation</span><span class="p">.</span><span class="n">Init</span><span class="p">(</span><span class="nb">NULL</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">JNIEnv</span><span class="o">*</span> <span class="n">env</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">startVm</span><span class="p">(</span><span class="o">&amp;</span><span class="n">mJavaVM</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">env</span><span class="p">,</span> <span class="n">zygote</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">onVmCreated</span><span class="p">(</span><span class="n">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="cm">/*
</span></span></span><span class="line"><span class="cl"><span class="cm">     * Register android functions.
</span></span></span><span class="line"><span class="cl"><span class="cm">     */</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">startReg</span><span class="p">(</span><span class="n">env</span><span class="p">)</span> <span class="o">&lt;</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">ALOGE</span><span class="p">(</span><span class="s">&#34;Unable to register all android natives</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">		
</span></span><span class="line"><span class="cl">  	 <span class="cm">/*
</span></span></span><span class="line"><span class="cl"><span class="cm">     * Start VM.  This thread becomes the main thread of the VM, and will
</span></span></span><span class="line"><span class="cl"><span class="cm">     * not return until the VM exits.
</span></span></span><span class="line"><span class="cl"><span class="cm">     */</span>
</span></span><span class="line"><span class="cl">    <span class="n">jclass</span> <span class="n">startClass</span> <span class="o">=</span> <span class="n">env</span><span class="o">-&gt;</span><span class="n">FindClass</span><span class="p">(</span><span class="n">slashClassName</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">		<span class="n">jmethodID</span> <span class="n">startMeth</span> <span class="o">=</span> <span class="n">env</span><span class="o">-&gt;</span><span class="n">GetStaticMethodID</span><span class="p">(</span><span class="n">startClass</span><span class="p">,</span> <span class="s">&#34;main&#34;</span><span class="p">,</span> <span class="s">&#34;([Ljava/lang/String;)V&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">env</span><span class="o">-&gt;</span><span class="n">CallStaticVoidMethod</span><span class="p">(</span><span class="n">startClass</span><span class="p">,</span> <span class="n">startMeth</span><span class="p">,</span> <span class="n">strArray</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>详细介绍可以会看 <a href="https://evilpan.com/2020/11/08/android-init/#native-%E5%B1%82" target="_blank" rel="noopener noreferrer">Android 用户态启动流程分析</a> 一文，这里我们只需要知道 Java 虚拟机是在 Zygote 进程创建的，并由子进程继承，因此 APP 从 zygote 进程中 fork 启动后就无需再次启动 Java 虚拟机，而是复用原有的虚拟机执行轻量的初始化即可。</p>
<h2 id="接口" class="headerLink">
    <a href="#%e6%8e%a5%e5%8f%a3" class="header-mark"></a>接口</h2><p>Android Java 虚拟机包括早期的 Dalvik 虚拟机和当前的 ART 虚拟机，我们将其统称为 Java 虚拟机，因为对于应用程序而言应该是透明的，也就是说二者应该提供了统一的对外接口。</p>
<p>这个接口可以分为两部分，一部分是提供给 Java 应用的接口，即我们常见的 JavaVM、JNIEnv 结构体提供的诸如 FindClass、GetMethodID、CallVoidMethod 等接口；另一部分则是提供给系统开发者的接口，系统通过这些接口去初始化并创建虚拟机，从而使自身具备执行 Java 代码的功能。</p>
<p><strong>JniInvocation.Init</strong> 方法中即进行了第二部分接口的初始化操作，其中主要逻辑是根据系统属性 (persist.sys.dalvik.vm.lib.2) 判断待加载的虚拟机动态库，Dalvik 虚拟机对应的是 libdvm.so，ART 虚拟机对应的是 libart.so；然后通过 <strong>dlopen</strong> 进行加载，并通过 <strong>dlsym</strong> 获取其中三个函数符号，作为抽象 Java 虚拟机的接口:</p>
<ul>
<li><strong>JNI_GetDefaultJavaVMInitArgs</strong>: 获取默认的 JVM 初始化参数；</li>
<li><strong>JNI_CreateJavaVM</strong>: 创建 Java 虚拟机；</li>
<li><strong>JNI_GetCreatedJavaVMs</strong>: 获取已经创建的 Java 虚拟机实例；</li>
</ul>
<p>例如，在上述 zygote 的 <code>AndroidRuntime::startVm</code> 方法实现中，就是通过指定参数最终调用 JNI_CreateJavaVM 来完成 Java 虚拟机的创建工作。</p>
<p>通过这三个接口实现了对于不同 Java 虚拟机细节的隐藏，既可以用 ART 无缝替换 Dalvik 虚拟机，也可以在未来用某个新的虚拟机无缝替换掉 ART 虚拟机。</p>
<p>总的来说，Java 虚拟机只在 Zygote 进程中创建一次，子进程通过 fork 获得虚拟机的一个副本，因此 zygote 才被称为所有 Java 进程的父进程；同时，也因为每个子进程拥有独立的虚拟机副本，所以某个进程的虚拟机崩溃后不影响其他进程，从而实现安全的运行时隔离。</p>
<h1 id="dalvik" class="headerLink">
    <a href="#dalvik" class="header-mark"></a>Dalvik</h1><p>Dalvik 是早期 Android 的 Java 虚拟机，伴随着 Android 5.0 的更新，正式宣告其历史使命的结束:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-42" 
    class="
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Author: Brian Carlstrom &lt;bdc@google.com&gt;
Date:   Tue Aug 5 12:46:17 2014 -0700

    Dalvik is dead, long live Dalvik!</code></pre></code></pre>
</div>
<p>虽然现在 Dalvik 已经被 ART 虚拟机所取代，但其简洁的实现有助于我们理解 Java 代码的运行流程，因此还是先对其进行简单的介绍。</p>
<p>上节中我们知道 zygote 进程创建并初始化 Java 虚拟机后执行的第一个 Java 函数是 <strong>com.android.internal.os.ZygoteInit</strong> 的 main 方法，这是个静态方法，因此在 Native 层调用的是 JNI 接口函数 <strong>CallStaticVoidMethod</strong>。其调用流程可以简化如下所示:</p>

<div class="table-wrapper">
  <table>
    <thead>
        <tr>
            <th style="text-align: ">method</th>
            <th style="text-align: ">file</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td style="text-align: "><strong>JNIEnv</strong>.CallStaticVoidMethod</td>
            <td style="text-align: ">dalvik/libnativehelper/include/nativehelper/jni.h</td>
        </tr>
        <tr>
            <td style="text-align: "><strong>JNINativeInterface</strong>.CallStaticVoidMethodV</td>
            <td style="text-align: ">dalvik/vm/Jni.c</td>
        </tr>
        <tr>
            <td style="text-align: "><strong>Jni</strong>.dvmCallMethodV</td>
            <td style="text-align: ">dalvik/vm/interp/Stack.c</td>
        </tr>
        <tr>
            <td style="text-align: "><strong>Stack</strong>.dvmInterpret</td>
            <td style="text-align: ">dalvik/vm/interp/Interp.c</td>
        </tr>
        <tr>
            <td style="text-align: ">dvmInterpretStd</td>
            <td style="text-align: ">dalvik/vm/mterp/out/InterpC-portstd.c (动态生成)</td>
        </tr>
    </tbody>
  </table>
</div>
<p>Dalvik 虚拟机支持三种执行模式，分别是:</p>
<ul>
<li>kExecutionModeInterpPortable: 可移植模式，能运行在不同的平台中，对应的运行方法是 dvmInterpretStd；</li>
<li>kExecutionModeInterpFast: 快速模式，针对特定平台优化，对应的运行方法是 dvmMterpStd；</li>
<li>kExecutionModeJit: JIT 模式，运行时编译为特定平台的 native 代码，对应运行方法也是 dvmMterpStd；</li>
</ul>
<p>以上述调用流程中的 portable 模式为例，对应 dvmInterpretStd 实现的核心代码如下所示:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-43" 
    class="
      chroma 
      !tw-block 
      tw-p-0
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      "><span class="line"><span class="cl"><span class="cp">#define INTERP_FUNC_NAME dvmInterpretStd
</span></span></span><span class="line"><span class="cl"><span class="cp"></span><span class="kt">bool</span> <span class="nf">INTERP_FUNC_NAME</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="n">InterpState</span><span class="o">*</span> <span class="n">interpState</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>
</span></span><span class="line"><span class="cl">    <span class="cm">/* core state */</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">Method</span><span class="o">*</span> <span class="n">curMethod</span><span class="p">;</span>    <span class="c1">// method we&#39;re interpreting
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">const</span> <span class="n">u2</span><span class="o">*</span> <span class="n">pc</span><span class="p">;</span>               <span class="c1">// program counter
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">u4</span><span class="o">*</span> <span class="n">fp</span><span class="p">;</span>                     <span class="c1">// frame pointer
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">u2</span> <span class="n">inst</span><span class="p">;</span>                    <span class="c1">// current instruction
</span></span></span><span class="line"><span class="cl"><span class="c1"></span> 
</span></span><span class="line"><span class="cl">    <span class="cm">/* copy state in */</span>
</span></span><span class="line"><span class="cl">    <span class="n">curMethod</span> <span class="o">=</span> <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">method</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">pc</span> <span class="o">=</span> <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">pc</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">fp</span> <span class="o">=</span> <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">fp</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">retval</span> <span class="o">=</span> <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">retval</span><span class="p">;</span>   <span class="cm">/* only need for kInterpEntryReturn? */</span>
</span></span><span class="line"><span class="cl"> 
</span></span><span class="line"><span class="cl">    <span class="n">methodClassDex</span> <span class="o">=</span> <span class="n">curMethod</span><span class="o">-&gt;</span><span class="n">clazz</span><span class="o">-&gt;</span><span class="n">pDvmDex</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">while</span> <span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="cm">/* fetch the next 16 bits from the instruction stream */</span>
</span></span><span class="line"><span class="cl">        <span class="n">inst</span> <span class="o">=</span> <span class="nf">FETCH</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">switch</span> <span class="p">(</span><span class="nf">INST_INST</span><span class="p">(</span><span class="n">inst</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="nf">HANDLE_OPCODE</span><span class="p">(</span><span class="n">OP_INVOKE_DIRECT</span> <span class="cm">/*vB, {vD, vE, vF, vG, vA}, meth@CCCC*/</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">                <span class="nf">GOTO_invoke</span><span class="p">(</span><span class="n">invokeDirect</span><span class="p">,</span> <span class="nb">false</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="n">OP_END</span>
</span></span><span class="line"><span class="cl">            <span class="nf">HANDLE_OPCODE</span><span class="p">(</span><span class="n">OP_RETURN</span> <span class="cm">/*vAA*/</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">            <span class="nf">HANDLE_OPCODE</span><span class="p">(...)</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="cm">/* export state changes */</span>
</span></span><span class="line"><span class="cl">    <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">method</span> <span class="o">=</span> <span class="n">curMethod</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">pc</span> <span class="o">=</span> <span class="n">pc</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">fp</span> <span class="o">=</span> <span class="n">fp</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="cm">/* debugTrackedRefStart doesn&#39;t change */</span>
</span></span><span class="line"><span class="cl">    <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">retval</span> <span class="o">=</span> <span class="n">retval</span><span class="p">;</span>   <span class="cm">/* need for _entryPoint=ret */</span>
</span></span><span class="line"><span class="cl">    <span class="n">interpState</span><span class="o">-&gt;</span><span class="n">nextMode</span> <span class="o">=</span> 
</span></span><span class="line"><span class="cl">        <span class="p">(</span><span class="n">INTERP_TYPE</span> <span class="o">==</span> <span class="n">INTERP_STD</span><span class="p">)</span> <span class="o">?</span> <span class="nl">INTERP_DBG</span> <span class="p">:</span> <span class="n">INTERP_STD</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="nb">true</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>可以看到其核心在于一个巨大的 switch/case，以 PC 为起点不断读取字节码(4字节对齐)，并根据 op_code 去分发解释执行不同的指令直到 Java 方法运行结束返回或者抛出异常。之所以称为可移植模式(portable)正是因为该代码纯粹是解释执行，既没有提前优化也没有运行时的 JIT 优化，也因此具有平台无关性，只要 C 编译器支持对应平台即可运行。</p>
<p>虽然 Dalvik 已经被 ART 取代，但其中的 Dalvik 字节码格式还是被保留了下来。即便在最新版本的 Android 中，编译 Java 生成的依旧是 DEX 文件，其格式可以参考 <a href="https://source.android.com/devices/tech/dalvik/dex-format" target="_blank" rel="noopener noreferrer">Dalvik Executable format</a>，Dalvik 字节码的介绍可以参考官方文档 <a href="https://source.android.com/devices/tech/dalvik/dalvik-bytecode" target="_blank" rel="noopener noreferrer">Dalvik bytecode</a>。</p>
<h1 id="art" class="headerLink">
    <a href="#art" class="header-mark"></a>ART</h1><p>ART 全称为 Android Runtime，是继 Dalvik 之后推出的高性能 Android Java 虚拟机。在本文中我们重点关注 ART 虚拟机执行 Java 代码的流程。在介绍 ART 的代码执行流程之前，我们需要先了解在 ART 中针对 DEX 的一系列提前优化方案，以及由此产生的各类中间文件。</p>
<h2 id="提前优化" class="headerLink">
    <a href="#%e6%8f%90%e5%89%8d%e4%bc%98%e5%8c%96" class="header-mark"></a>提前优化</h2><p>在我们使用 Android-Studio 编译应用时，实际上是通过 Java 编译器先将 <code>.java</code> 代码编译为对应的 Java 字节码，即 <code>.class</code> 类文件；然后用 <code>dx</code>(在新版本中是<code>d8</code>) 将 Java 字节码转换为 Dalvik 字节码，并将所有生成的类打包到统一的 DEX 文件中，最终和资源文件一起 zip 压缩为 <code>.apk</code> 文件。</p>
<p>在安装用户的 APK 时，Android 系统主要通过 PacketManager 对应用进行解包和安装。其中在处理 DEX 文件时候，会通过 <strong>installd</strong> 进程调用对应的二进制程序对字节码进行优化，这对于 Dalvik 虚拟机而言使用的是 <strong>dexopt</strong> 程序，而 ART 中使用的是 <strong>dex2oat</strong> 程序。</p>
<p>dexopt 将 dex 文件优化为 odex 文件，即 optimized-dex 的缩写，其中包含的是优化后的 Dalvik 字节码，称为 quickend dex；dex2oat 基于 LLVM，优化后生成的是对应平台的二进制代码，以 oat 格式保存，oat 的全称为 Ahead-Of-Time。oat 文件实际上是以 ELF 格式进行存储的，并在其中 oatdata 段(section) 包含了原始的 DEX 内容。</p>
<p>在 Android 8 之后，将 OAT 文件一分为二，原 oat 仍然是 ELF 格式，但原始 DEX 文件内容被保存到了 VDEX 中，VDEX 有其独立的文件格式。整体流程如下图所示:</p>
<p><figure><a class="lightgallery" href="/img/2021-12-26-art-internal/1.png" title="Java 代码处理流程" data-thumbnail="/img/2021-12-26-art-internal/1.png" data-sub-html="<h2>LIEF Documentation - Android formats</h2><p>Java 代码处理流程</p>"><img  loading="lazy" src='/img/2021-12-26-art-internal/1.png'   alt="Java 代码处理流程"  ></a><figcaption class="image-caption">LIEF Documentation - Android formats</figcaption>
</figure></p>
<p>值得一提的是，在 Andorid 系统中 dex2oat 会将优化后的代码保存在 <code>/data/app</code> 对应的应用路径下，系统应用会保存在 <code>/data/dalvik-cache/</code> 下，对于后者，产生的实际有三个文件，比如:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-44" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ ls -l <span class="p">|</span> grep Settings.apk
</span></span><span class="line"><span class="cl">-rw-r----- <span class="m">1</span> system system           <span class="m">77824</span> 2021-12-10 10:33 system_ext@priv-app@Settings@Settings.apk@classes.art
</span></span><span class="line"><span class="cl">-rw-r----- <span class="m">1</span> system system          <span class="m">192280</span> 2021-11-19 12:50 system_ext@priv-app@Settings@Settings.apk@classes.dex
</span></span><span class="line"><span class="cl">-rw-r----- <span class="m">1</span> system system           <span class="m">59646</span> 2021-12-10 10:33 system_ext@priv-app@Settings@Settings.apk@classes.vdex</span></span></code></pre>
</div>
<p><code>system_ext@priv-app@Settings@Settings.apk@classes.dex</code> 实际上是 ELF 格式的 OAT 文件，所以我们不能以貌(后缀)取人；<code>.art</code> 也是一个特殊的文件格式，如前文所言，Android 实现了自己的 Java 虚拟机，这个虚拟机本身是用 C/C++ 实现的，其中的一些 Java 原语有对应的 C++ 类，比如:</p>
<ul>
<li>java.lang.Class 对应 art::mirror::Class</li>
<li>java.lang.String 对应 art::mirror::String</li>
<li>java.lang.reflect.Method 对应 art::mirror::Method</li>
<li>……</li>
</ul>
<p>当创建一个 Java 对象时，内存中会创建对应的 C++ 对象并调用其构造函数，JVM 管理者这些 C++ 对象的引用。为了加速启动过程，避免对这些常见类的初始化，Android 使用了 <code>.art</code> 格式来保存这些 C++ 对象的实例，简单来说，art 文件可以看做是一系列常用 C++ 对象的内存 dump。</p>
<p>不论是 oat、vdex 还是 art，都是 Android 定义的内部文件格式，官方并不保证其兼容性，事实上在 Android 各个版本中这些文件格式都有不同程度的变化，这些变化是不反映在文档中的，只能通过代码去一窥究竟。因此对于这些文件格式我们现在只需要知道其大致作用，无需关心其实现细节。</p>
<h2 id="文件加载" class="headerLink">
    <a href="#%e6%96%87%e4%bb%b6%e5%8a%a0%e8%bd%bd" class="header-mark"></a>文件加载</h2><p>在前一篇文章 (<a href="https://evilpan.com/2021/12/05/apk-startup/" target="_blank" rel="noopener noreferrer">Android 12 应用启动流程分析</a>) 中我们知道 APP 最终在 ActivityThread 中完成 Application 的创建和初始化，最终调用 Activity.onCreate 进入视图组件的生命周期。但这里其实忽略了一个问题: APP 的代码(DEX/OAT 文件) 是如何加载到进程中的？</p>
<p>在 Java 中负责加载指定类的对象是 <a href="https://docs.oracle.com/javase/7/docs/api/java/lang/ClassLoader.html" target="_blank" rel="noopener noreferrer">ClassLoader</a>，Android 中也是类似，BaseDexClassLoader 继承自 ClassLoader 类，实现了许多 DEX 相关的加载操作，其子类包括:</p>
<ul>
<li>DexClassLoader: 负责从 <code>.jar</code> 或者 <code>.apk</code> 中加载类；</li>
<li>PathClassLoader: 负责从本地文件中初始化类加载器；</li>
<li>InMemoryDexClassLoader: 从内存中初始化类加载器；</li>
</ul>
<h3 id="classloader" class="headerLink">
    <a href="#classloader" class="header-mark"></a>ClassLoader</h3><p>以常见的 <code>PathClassLoader</code> 为例，其构造函数会调用父类的构造函数，整体调用链路简化如下表:</p>

<div class="table-wrapper">
  <table>
    <thead>
        <tr>
            <th style="text-align: ">method</th>
            <th style="text-align: ">file</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td style="text-align: ">new PathClassLoader</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">new BaseDexClassLoader</td>
            <td style="text-align: ">libcore/dalvik/src/main/java/dalvik/system/BaseDexClassLoader.java</td>
        </tr>
        <tr>
            <td style="text-align: ">new DexPathList</td>
            <td style="text-align: ">libcore/dalvik/src/main/java/dalvik/system/DexPathList.java</td>
        </tr>
        <tr>
            <td style="text-align: ">DexPathList.makeDexElements</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">DexPathList.loadDexFile</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">new DexFile</td>
            <td style="text-align: ">libcore/dalvik/src/main/java/dalvik/system/DexFile.java</td>
        </tr>
        <tr>
            <td style="text-align: ">DexFile.openDexFile</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">DexFile.openDexFileNative</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: "><strong>DexFile_openDexFileNative</strong></td>
            <td style="text-align: ">art/runtime/native/dalvik_system_DexFile.cc</td>
        </tr>
        <tr>
            <td style="text-align: ">OatFileManager::OpenDexFilesFromOat</td>
            <td style="text-align: ">art/runtime/oat_file_manager.cc</td>
        </tr>
    </tbody>
  </table>
</div>
<p>在 <strong>OpenDexFilesFromOat</strong> 中执行了真正的代码加载工作，伪代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
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        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

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          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-45" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;&gt;</span> <span class="n">OatFileManager</span><span class="o">::</span><span class="n">OpenDexFilesFromOat</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;&gt;</span> <span class="n">dex_files</span> <span class="o">=</span> <span class="n">OpenDexFilesFromOat_Impl</span><span class="p">(...);</span>
</span></span><span class="line"><span class="cl">    <span class="k">for</span> <span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;&amp;</span> <span class="nl">dex_file</span> <span class="p">:</span> <span class="n">dex_files</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">dex_file</span><span class="o">-&gt;</span><span class="n">DisableWrite</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">error_msgs</span><span class="o">-&gt;</span><span class="n">push_back</span><span class="p">(</span><span class="s">&#34;Failed to make dex file &#34;</span> <span class="o">+</span> <span class="n">dex_file</span><span class="o">-&gt;</span><span class="n">GetLocation</span><span class="p">()</span> <span class="o">+</span> <span class="s">&#34; read-only&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">      <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">dex_files</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>通过 OpenDexFilesFromOat_Impl 加载获取 DexFile 结构体数组，值得注意的是加载完 DEX 之后会将内存中的 dex_file 设置为不可写，当然目前还没有强制，但可见这是未来的趋势。</p>
<p>继续看实现部分是如何加载 Dex 文件的:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
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    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
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          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

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        class="
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          hover:tw-text-fgColor-link 
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-46" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;&gt;</span> <span class="n">OatFileManager</span><span class="o">::</span><span class="n">OpenDexFilesFromOat_Impl</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Extract dex file headers from `dex_mem_maps`.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">const</span> <span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">::</span><span class="n">Header</span><span class="o">*&gt;</span> <span class="n">dex_headers</span> <span class="o">=</span> <span class="n">GetDexFileHeaders</span><span class="p">(</span><span class="n">dex_mem_maps</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Determine dex/vdex locations and the combined location checksum.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">dex_location</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">vdex_path</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kt">bool</span> <span class="n">has_vdex</span> <span class="o">=</span> <span class="n">OatFileAssistant</span><span class="o">::</span><span class="n">AnonymousDexVdexLocation</span><span class="p">(</span><span class="n">dex_headers</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                             <span class="n">kRuntimeISA</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                             <span class="o">&amp;</span><span class="n">dex_location</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                             <span class="o">&amp;</span><span class="n">vdex_path</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">has_vdex</span> <span class="o">&amp;&amp;</span> <span class="n">OS</span><span class="o">::</span><span class="n">FileExists</span><span class="p">(</span><span class="n">vdex_path</span><span class="p">.</span><span class="n">c_str</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">vdex_file</span> <span class="o">=</span> <span class="n">VdexFile</span><span class="o">::</span><span class="n">Open</span><span class="p">(</span><span class="n">vdex_path</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="cm">/* writable= */</span> <span class="nb">false</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="cm">/* low_4gb= */</span> <span class="nb">false</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="cm">/* unquicken= */</span> <span class="nb">false</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="o">&amp;</span><span class="n">error_msg</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Load dex files. Skip structural dex file verification if vdex was found
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// and dex checksums matched.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;&gt;</span> <span class="n">dex_files</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">for</span> <span class="p">(</span><span class="n">size_t</span> <span class="n">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="n">i</span> <span class="o">&lt;</span> <span class="n">dex_mem_maps</span><span class="p">.</span><span class="n">size</span><span class="p">();</span> <span class="o">++</span><span class="n">i</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">static</span> <span class="k">constexpr</span> <span class="kt">bool</span> <span class="n">kVerifyChecksum</span> <span class="o">=</span> <span class="nb">true</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">const</span> <span class="n">ArtDexFileLoader</span> <span class="n">dex_file_loader</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">&gt;</span> <span class="n">dex_file</span><span class="p">(</span><span class="n">dex_file_loader</span><span class="p">.</span><span class="n">Open</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">            <span class="n">DexFileLoader</span><span class="o">::</span><span class="n">GetMultiDexLocation</span><span class="p">(</span><span class="n">i</span><span class="p">,</span> <span class="n">dex_location</span><span class="p">.</span><span class="n">c_str</span><span class="p">()),</span>
</span></span><span class="line"><span class="cl">            <span class="n">dex_headers</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="o">-&gt;</span><span class="n">checksum_</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">            <span class="n">std</span><span class="o">::</span><span class="n">move</span><span class="p">(</span><span class="n">dex_mem_maps</span><span class="p">[</span><span class="n">i</span><span class="p">]),</span>
</span></span><span class="line"><span class="cl">            <span class="cm">/* verify= */</span> <span class="p">(</span><span class="n">vdex_file</span> <span class="o">==</span> <span class="k">nullptr</span><span class="p">)</span> <span class="o">&amp;&amp;</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">IsVerificationEnabled</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">            <span class="n">kVerifyChecksum</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">            <span class="o">&amp;</span><span class="n">error_msg</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">dex_file</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">dex</span><span class="o">::</span><span class="n">tracking</span><span class="o">::</span><span class="n">RegisterDexFile</span><span class="p">(</span><span class="n">dex_file</span><span class="p">.</span><span class="n">get</span><span class="p">());</span>  <span class="c1">// Register for tracking.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>            <span class="n">dex_files</span><span class="p">.</span><span class="n">push_back</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">move</span><span class="p">(</span><span class="n">dex_file</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Initialize an OatFile instance backed by the loaded vdex.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">std</span><span class="o">::</span><span class="n">unique_ptr</span><span class="o">&lt;</span><span class="n">OatFile</span><span class="o">&gt;</span> <span class="n">oat_file</span><span class="p">(</span><span class="n">OatFile</span><span class="o">::</span><span class="n">OpenFromVdex</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="n">MakeNonOwningPointerVector</span><span class="p">(</span><span class="n">dex_files</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">        <span class="n">std</span><span class="o">::</span><span class="n">move</span><span class="p">(</span><span class="n">vdex_file</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">        <span class="n">dex_location</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">oat_file</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">VLOG</span><span class="p">(</span><span class="n">class_linker</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="s">&#34;Registering &#34;</span> <span class="o">&lt;&lt;</span> <span class="n">oat_file</span><span class="o">-&gt;</span><span class="n">GetLocation</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">        <span class="o">*</span><span class="n">out_oat_file</span> <span class="o">=</span> <span class="n">RegisterOatFile</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">move</span><span class="p">(</span><span class="n">oat_file</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">dex_files</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>加载过程首先将 vdex 映射到内存中，然后将已经映射到内存中的 dex 或者在磁盘中的 dex 转换为 DexFile 结构体，最后再将 vdex 和 oat 文件关联起来。</p>
<h3 id="vdexfile" class="headerLink">
    <a href="#vdexfile" class="header-mark"></a>VdexFile</h3><p>vdex 是 Android 8.0 加入的新文件格式，主要用于保存优化代码的原始 DEX 信息，而 OAT 中则主要保存 dex2oat 编译后的 Native 代码。</p>
<p>VdexFile 的结构大致如下所示，其中 <code>D</code> 代表 VDEX 中包含的 DEX 文件个数:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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    ">      
    <button 
      class="
        code-block-button
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
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          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
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        title="Toggle code wrap"><svg class="icon"
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      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-47" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>VdexFileHeader    fixed-length header
VdexSectionHeader[kNumberOfSections]

Checksum section
  VdexChecksum[D]

Optionally:
   DexSection
       DEX[0]                array of the input DEX files
       DEX[1]
       ...
       DEX[D-1]

VerifierDeps
   4-byte alignment
   uint32[D]                  DexFileDeps offsets for each dex file
   DexFileDeps[D][]           verification dependencies
     4-byte alignment
     uint32[class_def_size]     TypeAssignability offsets (kNotVerifiedMarker for a class that isn&#39;t verified)
     uint32                     Offset of end of AssignabilityType sets
     uint8[]                    AssignabilityType sets
     4-byte alignment
     uint32                     Number of strings
     uint32[]                   String data offsets for each string
     uint8[]                    String data</code></pre></code></pre>
</div>
<blockquote>
  <p>VdexFile 结构详见: <a href="https://cs.android.com/android/platform/superproject/&#43;/master:art/runtime/vdex_file.h" target="_blank" rel="noopener noreferrer"><em>art/runtime/vdex_file.h</em></a></p>
</blockquote><h3 id="dexfile" class="headerLink">
    <a href="#dexfile" class="header-mark"></a>DexFile</h3><p><strong>dex_file_loader.Open</strong> 的调用路径如下:</p>
<ul>
<li>ArtDexFileLoader::Open</li>
<li>ArtDexFileLoader::OpenCommon</li>
<li>DexFileLoader::OpenCommon
<ul>
<li>magic == &ldquo;dex\n&rdquo; -&gt; new StandardDexFile()</li>
<li>magic == &ldquo;cdex&rdquo;  -&gt; new CompactDexFile()</li>
</ul>
</li>
</ul>
<p>实际根据起始 4 字节判断是标准 DEX 还是紧凑型 DEX (cdex, compat dex)，并使用对应的结构体进行初始化。cdex 是当前 ART 内部使用的 DEX 文件格式，主要是为了减少磁盘和内存的使用。但不论是 StandardDexFile 还是 CompactDexFile 都继承于 DexFile，二者的构造函数最终还是会调用 DexFile 的构造函数。</p>
<blockquote>
  <p>DexFile 结构详见 <a href="https://cs.android.com/android/platform/superproject/&#43;/master:art/libdexfile/dex/dex_file.h" target="_blank" rel="noopener noreferrer"><em>art/libdexfile/dex/dex_file.h</em></a></p>
</blockquote><h3 id="oatfile" class="headerLink">
    <a href="#oatfile" class="header-mark"></a>OatFile</h3><p>在完成所有 DexFile 的初始化之后，会继续使用 <code>OatFile::OpenFromVdex</code> 创建 oat_file 并进行注册。该函数的调用链路如下:</p>
<ul>
<li>OatFile::OpenFromVdex</li>
<li>OatFileBackedByVdex::Open</li>
<li>new OatFileBackedByVdex</li>
<li>OatFileBase::OatFileBase</li>
<li>OatFile::OatFile</li>
</ul>
<p>与早期使用 odex 的区别是现在在创建完 OatFile 之后，会调用 <code>oat_file-&gt;SetVdex</code> 获取 vdex 对象的所有权，用以实现 OAT 的部分接口，比如获取内存中对应 DEX 文件的起始地址:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
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    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-48" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">const</span> <span class="kt">uint8_t</span><span class="o">*</span> <span class="n">OatFile</span><span class="o">::</span><span class="n">DexBegin</span><span class="p">()</span> <span class="k">const</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="n">vdex_</span><span class="o">-&gt;</span><span class="n">Begin</span><span class="p">();</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<blockquote>
  <p>详见: art/runtime/oat_file.h</p>
</blockquote><h2 id="方法调用" class="headerLink">
    <a href="#%e6%96%b9%e6%b3%95%e8%b0%83%e7%94%a8" class="header-mark"></a>方法调用</h2><p>本来按照时间线来看的话，这里应该先介绍 ART 运行时类和方法的加载过程，但我从实践出发，先看 Java 方法的调用过程，并针对其中涉及到的概念在下一节继续介绍。</p>
<p>在 Web 安全中，Java 服务端通常带有一个称为 RASP (Runtime Application Self-Protection) 的动态防护方案，比如监控某些执行命令的敏感函数调用并进行告警，其实际 hook 点是在 JVM 中，不论是方法直接调用还是反射调用都可以检测到。因此我们有理由猜测在 Android 中也有类似的调用链路，为了方便观察，这里先看反射调用的场景，一般反射调用的示例如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-49" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="nn">java.lang.reflect.*</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="kd">public</span><span class="w"> </span><span class="kd">class</span> <span class="nc">Test</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="w"> </span><span class="n">args</span><span class="o">[]</span><span class="p">)</span><span class="w"> </span><span class="kd">throws</span><span class="w"> </span><span class="n">Exception</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">Class</span><span class="w"> </span><span class="n">c</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Class</span><span class="p">.</span><span class="na">forName</span><span class="p">(</span><span class="s">&#34;com.evilpan.DemoClass&#34;</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">Method</span><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">c</span><span class="p">.</span><span class="na">getMethod</span><span class="p">(</span><span class="s">&#34;foo&#34;</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">m</span><span class="p">.</span><span class="na">invoke</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>因此一个方法的调用会进入到 <code>Method.invoke</code> 方法，这是一个 <strong>native 方法</strong>，实际实现在 <em>art/runtime/native/java_lang_reflect_Method.cc</em>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-50" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="n">jobject</span> <span class="nf">Method_invoke</span><span class="p">(</span><span class="n">JNIEnv</span><span class="o">*</span> <span class="n">env</span><span class="p">,</span> <span class="n">jobject</span> <span class="n">javaMethod</span><span class="p">,</span> <span class="n">jobject</span> <span class="n">javaReceiver</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                             <span class="n">jobjectArray</span> <span class="n">javaArgs</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="n">ScopedFastNativeObjectAccess</span> <span class="n">soa</span><span class="p">(</span><span class="n">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="n">InvokeMethod</span><span class="o">&lt;</span><span class="n">kRuntimePointerSize</span><span class="o">&gt;</span><span class="p">(</span><span class="n">soa</span><span class="p">,</span> <span class="n">javaMethod</span><span class="p">,</span> <span class="n">javaReceiver</span><span class="p">,</span> <span class="n">javaArgs</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>InvokeMethod 定义在 <em>art/runtime/reflection.cc</em>，其实现的核心代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-51" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">template</span> <span class="o">&lt;</span><span class="n">PointerSize</span> <span class="n">kPointerSize</span><span class="o">&gt;</span>
</span></span><span class="line"><span class="cl"><span class="n">jobject</span> <span class="n">InvokeMethod</span><span class="p">(</span><span class="k">const</span> <span class="n">ScopedObjectAccessAlreadyRunnable</span><span class="o">&amp;</span> <span class="n">soa</span><span class="p">,</span> <span class="n">jobject</span> <span class="n">javaMethod</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                     <span class="n">jobject</span> <span class="n">javaReceiver</span><span class="p">,</span> <span class="n">jobject</span> <span class="n">javaArgs</span><span class="p">,</span> <span class="n">size_t</span> <span class="n">num_frames</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Executable</span><span class="o">&gt;</span> <span class="n">executable</span> <span class="o">=</span> <span class="n">soa</span><span class="p">.</span><span class="n">Decode</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Executable</span><span class="o">&gt;</span><span class="p">(</span><span class="n">javaMethod</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="kt">bool</span> <span class="n">accessible</span> <span class="o">=</span> <span class="n">executable</span><span class="o">-&gt;</span><span class="n">IsAccessible</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">ArtMethod</span><span class="o">*</span> <span class="n">m</span> <span class="o">=</span> <span class="n">executable</span><span class="o">-&gt;</span><span class="n">GetArtMethod</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="o">!</span><span class="n">declaring_class</span><span class="o">-&gt;</span><span class="n">IsVisiblyInitialized</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">Thread</span><span class="o">*</span> <span class="n">self</span> <span class="o">=</span> <span class="n">soa</span><span class="p">.</span><span class="n">Self</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">        <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetClassLinker</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">EnsureInitialized</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">            <span class="n">self</span><span class="p">,</span> <span class="n">h_class</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">            <span class="cm">/*can_init_fields=*/</span> <span class="nb">true</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">            <span class="cm">/*can_init_parents=*/</span> <span class="nb">true</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">m</span><span class="o">-&gt;</span><span class="n">IsStatic</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">declaring_class</span><span class="o">-&gt;</span><span class="n">IsStringClass</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="n">m</span><span class="o">-&gt;</span><span class="n">IsConstructor</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">m</span> <span class="o">=</span> <span class="n">WellKnownClasses</span><span class="o">::</span><span class="n">StringInitToStringFactory</span><span class="p">(</span><span class="n">m</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">m</span> <span class="o">=</span> <span class="n">receiver</span><span class="o">-&gt;</span><span class="n">GetClass</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">FindVirtualMethodForVirtualOrInterface</span><span class="p">(</span><span class="n">m</span><span class="p">,</span> <span class="n">kPointerSize</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">accessible</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="n">VerifyAccess</span><span class="p">(</span><span class="cm">/*...*/</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">ThrowIllegalAccessException</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="n">StringPrintf</span><span class="p">(</span><span class="s">&#34;Class %s cannot access %s method %s of class %s&#34;</span><span class="p">,</span> <span class="p">...));</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">InvokeMethodImpl</span><span class="p">(</span><span class="n">soa</span><span class="p">,</span> <span class="n">m</span><span class="p">,</span> <span class="n">np_method</span><span class="p">,</span> <span class="n">receiver</span><span class="p">,</span> <span class="n">objects</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">shorty</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">result</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>上面省略了许多细节，主要是做了一些调用前的检查和预处理工作，流程可以概况为:</p>
<ol>
<li>判断方法所属的类是否已经初始化过，如果没有则进行初始化；</li>
<li>将 <code>String.&lt;init&gt;</code> 构造函数调用替换为对应的工厂 <code>StringFactory</code> 方法调用；</li>
<li>如果是虚函数调用，替换为运行时实际的函数；</li>
<li>判断方法是否可以访问，如果不能访问则抛出异常；</li>
<li>调用函数；</li>
</ol>
<p>值得注意的是，jobject 类型的 javaMethod 可以转换为 <code>ArtMethod</code> 指针，该结构体是 ART 虚拟机中对于具体方法的描述。之后经过一系列调用:</p>
<ul>
<li>InvokeMethodImpl</li>
<li>InvokeWithArgArray</li>
<li><code>method-&gt;Invoke()</code></li>
</ul>
<p>最终进入 <code>ArtMethod::Invoke</code> 函数，还是只看核心代码:</p>
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      </button>

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      <button 
        class="
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      <button 
        class="
          copy-code-button
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          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-52" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">ArtMethod</span><span class="o">::</span><span class="n">Invoke</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span> <span class="kt">uint32_t</span><span class="o">*</span> <span class="n">args</span><span class="p">,</span> <span class="kt">uint32_t</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">JValue</span><span class="o">*</span> <span class="n">result</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                       <span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">shorty</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">Runtime</span><span class="o">*</span> <span class="n">runtime</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="o">!</span><span class="n">runtime</span><span class="o">-&gt;</span><span class="n">IsStarted</span><span class="p">()</span> <span class="o">||</span>
</span></span><span class="line"><span class="cl">               <span class="p">(</span><span class="n">self</span><span class="o">-&gt;</span><span class="n">IsForceInterpreter</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="n">IsProxyMethod</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="n">IsInvokable</span><span class="p">())))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">art</span><span class="o">::</span><span class="n">interpreter</span><span class="o">::</span><span class="n">EnterInterpreterFromInvoke</span><span class="p">(...);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="kt">bool</span> <span class="n">have_quick_code</span> <span class="o">=</span> <span class="n">GetEntryPointFromQuickCompiledCode</span><span class="p">()</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">LIKELY</span><span class="p">(</span><span class="n">have_quick_code</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">IsStatic</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="p">(</span><span class="o">*</span><span class="n">art_quick_invoke_stub</span><span class="p">)(</span><span class="k">this</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">self</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="n">shorty</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="p">(</span><span class="o">*</span><span class="n">art_quick_invoke_static_stub</span><span class="p">)(</span><span class="k">this</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">args_size</span><span class="p">,</span> <span class="n">self</span><span class="p">,</span> <span class="n">result</span><span class="p">,</span> <span class="n">shorty</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">LOG</span><span class="p">(</span><span class="n">INFO</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="s">&#34;Not invoking &#39;&#34;</span> <span class="o">&lt;&lt;</span> <span class="n">PrettyMethod</span><span class="p">()</span> <span class="o">&lt;&lt;</span> <span class="s">&#34;&#39; code=null&#34;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">self</span><span class="o">-&gt;</span><span class="n">PopManagedStackFragment</span><span class="p">(</span><span class="n">fragment</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>ART 对于 Java 方法实现了两种执行模式，一种是像 Dalvik 虚拟机一样解释执行字节码，姑且称为解释模式；另一种是快速模式，即直接调用通过 OAT 编译后的本地代码。</p>
<blockquote>
  <p>在 ART 早期指定本地代码还细分为 Portable 和 Quick 两种模式，但由于对极致速度的追求以及随着 Quick 模式的不断优化，Portable 也逐渐退出了历史舞台。</p>
</blockquote><p>阅读上述代码可以得知，当 ART 运行时尚未启动或者指定强制使用解释执行时，虚拟机执行函数使用的是解释模式，ART 可以在启动时指定 <code>-Xint</code> 参数强制使用解释执行，但即便指定了使用解释执行模式，还是有一些情况无法使用解释执行，比如:</p>
<ol>
<li>当所执行的方法是 Native 方法时，这时只有二进制代码，不存在字节码，自然无法解释执行；</li>
<li>当所执行的方法无法调用，比如 access_flag 判定无法访问或者当前方法是抽象方法时；</li>
<li>当所执行的方式是代理方法时，ART 对于代理方法有单独的本地调用方式；</li>
</ol>
<h3 id="解释执行" class="headerLink">
    <a href="#%e8%a7%a3%e9%87%8a%e6%89%a7%e8%a1%8c" class="header-mark"></a>解释执行</h3><p>解释执行的入口是 <code>art::interpreter::EnterInterpreterFromInvoke</code>，该函数定义在 <em>art/runtime/interpreter/interpreter.cc</em>，关键代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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      class="
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      </button>

   <div class="tw-flex">
      <button 
        class="
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        title="Toggle line numbers"><svg class="icon"
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      <button 
        class="
          wrap-code-button
          tw-select-none 
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-53" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="nf">EnterInterpreterFromInvoke</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="n">ArtMethod</span><span class="o">*</span> <span class="n">method</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Object</span><span class="o">&gt;</span> <span class="n">receiver</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="kt">uint32_t</span><span class="o">*</span> <span class="n">args</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="n">JValue</span><span class="o">*</span> <span class="n">result</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                <span class="kt">bool</span> <span class="n">stay_in_interpreter</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">CodeItemDataAccessor</span> <span class="n">accessor</span><span class="p">(</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">DexInstructionData</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">accessor</span><span class="p">.</span><span class="n">HasCodeItem</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">num_regs</span> <span class="o">=</span>  <span class="n">accessor</span><span class="p">.</span><span class="n">RegistersSize</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">        <span class="n">num_ins</span> <span class="o">=</span> <span class="n">accessor</span><span class="p">.</span><span class="n">InsSize</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// 初始化栈帧 ......
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">LIKELY</span><span class="p">(</span><span class="o">!</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">JValue</span> <span class="n">r</span> <span class="o">=</span> <span class="n">Execute</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">accessor</span><span class="p">,</span> <span class="o">*</span><span class="n">shadow_frame</span><span class="p">,</span> <span class="n">JValue</span><span class="p">(),</span> <span class="n">stay_in_interpreter</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">result</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="o">*</span><span class="n">result</span> <span class="o">=</span> <span class="n">r</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中的 <code>CodeItem</code> 就是 DEX 文件中对应方法的字节码，还是老样子，直接看简化的调用链路:</p>

<div class="table-wrapper">
  <table>
    <thead>
        <tr>
            <th style="text-align: ">method</th>
            <th style="text-align: ">file</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td style="text-align: ">Execute</td>
            <td style="text-align: ">art/runtime/interpreter/interpreter.cc</td>
        </tr>
        <tr>
            <td style="text-align: ">ExecuteSwitch</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">ExecuteSwitchImpl</td>
            <td style="text-align: ">art/runtime/interpreter/interpreter_switch_impl.h</td>
        </tr>
        <tr>
            <td style="text-align: ">ExecuteSwitchImplAsm</td>
            <td style="text-align: ">&hellip;</td>
        </tr>
        <tr>
            <td style="text-align: ">ExecuteSwitchImplAsm</td>
            <td style="text-align: ">art/runtime/arch/arm64/quick_entrypoints_arm64.S</td>
        </tr>
        <tr>
            <td style="text-align: ">ExecuteSwitchImplCpp</td>
            <td style="text-align: ">art/runtime/interpreter/interpreter_switch_impl-inl.h</td>
        </tr>
    </tbody>
  </table>
</div>
<p><code>ExecuteSwitchImplAsm</code> 为了速度直接使用汇编实现，在 ARM64 平台中的定义如下:</p>
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      aria-hidden="true">
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          <p class="tw-select-none !tw-my-1">c</p>
      </button>

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        class="
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-54" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">//  Wrap ExecuteSwitchImpl in assembly method which specifies DEX PC for unwinding.
</span></span></span><span class="line"><span class="cl"><span class="c1">//  Argument 0: x0: The context pointer for ExecuteSwitchImpl.
</span></span></span><span class="line"><span class="cl"><span class="c1">//  Argument 1: x1: Pointer to the templated ExecuteSwitchImpl to call.
</span></span></span><span class="line"><span class="cl"><span class="c1">//  Argument 2: x2: The value of DEX PC (memory address of the methods bytecode).
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="n">ENTRY</span> <span class="n">ExecuteSwitchImplAsm</span>
</span></span><span class="line"><span class="cl">    <span class="n">SAVE_TWO_REGS_INCREASE_FRAME</span> <span class="n">x19</span><span class="p">,</span> <span class="n">xLR</span><span class="p">,</span> <span class="mi">16</span>
</span></span><span class="line"><span class="cl">    <span class="n">mov</span> <span class="n">x19</span><span class="p">,</span> <span class="n">x2</span>                                   <span class="c1">// x19 = DEX PC
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nf">CFI_DEFINE_DEX_PC_WITH_OFFSET</span><span class="p">(</span><span class="mi">0</span> <span class="cm">/* x0 */</span><span class="p">,</span> <span class="mi">19</span> <span class="cm">/* x19 */</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">blr</span> <span class="n">x1</span>                                        <span class="c1">// Call the wrapped method.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">RESTORE_TWO_REGS_DECREASE_FRAME</span> <span class="n">x19</span><span class="p">,</span> <span class="n">xLR</span><span class="p">,</span> <span class="mi">16</span>
</span></span><span class="line"><span class="cl">    <span class="n">ret</span>
</span></span><span class="line"><span class="cl"><span class="n">END</span> <span class="n">ExecuteSwitchImplAsm</span></span></span></code></pre>
</div>
<p>本质上是调用保存在 x1 寄存器的第二个参数，调用处的代码片段如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
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          <p class="tw-select-none !tw-my-1">cpp</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-55" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
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      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
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      "><span class="line"><span class="cl"><span class="k">template</span><span class="o">&lt;</span><span class="kt">bool</span> <span class="n">do_access_check</span><span class="p">,</span> <span class="kt">bool</span> <span class="n">transaction_active</span><span class="o">&gt;</span>
</span></span><span class="line"><span class="cl"><span class="n">ALWAYS_INLINE</span> <span class="n">JValue</span> <span class="n">ExecuteSwitchImpl</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">//...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kt">void</span><span class="o">*</span> <span class="n">impl</span> <span class="o">=</span> <span class="k">reinterpret_cast</span><span class="o">&lt;</span><span class="kt">void</span><span class="o">*&gt;</span><span class="p">(</span><span class="o">&amp;</span><span class="n">ExecuteSwitchImplCpp</span><span class="o">&lt;</span><span class="n">do_access_check</span><span class="p">,</span> <span class="n">transaction_active</span><span class="o">&gt;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="kt">uint16_t</span><span class="o">*</span> <span class="n">dex_pc</span> <span class="o">=</span> <span class="n">ctx</span><span class="p">.</span><span class="n">accessor</span><span class="p">.</span><span class="n">Insns</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">ExecuteSwitchImplAsm</span><span class="p">(</span><span class="o">&amp;</span><span class="n">ctx</span><span class="p">,</span> <span class="n">impl</span><span class="p">,</span> <span class="n">dex_pc</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>即调用了 <code>ExecuteSwitchImplCpp</code>，在该函数中，可以看见典型的解释执行代码:</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-56" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="k">template</span><span class="o">&lt;</span><span class="kt">bool</span> <span class="n">do_access_check</span><span class="p">,</span> <span class="kt">bool</span> <span class="n">transaction_active</span><span class="o">&gt;</span>
</span></span><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">ExecuteSwitchImplCpp</span><span class="p">(</span><span class="n">SwitchImplContext</span><span class="o">*</span> <span class="n">ctx</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">Thread</span><span class="o">*</span> <span class="n">self</span> <span class="o">=</span> <span class="n">ctx</span><span class="o">-&gt;</span><span class="n">self</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">CodeItemDataAccessor</span><span class="o">&amp;</span> <span class="n">accessor</span> <span class="o">=</span> <span class="n">ctx</span><span class="o">-&gt;</span><span class="n">accessor</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">ShadowFrame</span><span class="o">&amp;</span> <span class="n">shadow_frame</span> <span class="o">=</span> <span class="n">ctx</span><span class="o">-&gt;</span><span class="n">shadow_frame</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">self</span><span class="o">-&gt;</span><span class="n">VerifyStack</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kt">uint32_t</span> <span class="n">dex_pc</span> <span class="o">=</span> <span class="n">shadow_frame</span><span class="p">.</span><span class="n">GetDexPC</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="k">auto</span><span class="o">*</span> <span class="k">const</span> <span class="n">instrumentation</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetInstrumentation</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="kt">uint16_t</span><span class="o">*</span> <span class="k">const</span> <span class="n">insns</span> <span class="o">=</span> <span class="n">accessor</span><span class="p">.</span><span class="n">Insns</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">Instruction</span><span class="o">*</span> <span class="n">next</span> <span class="o">=</span> <span class="n">Instruction</span><span class="o">::</span><span class="n">At</span><span class="p">(</span><span class="n">insns</span> <span class="o">+</span> <span class="n">dex_pc</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">while</span> <span class="p">(</span><span class="nb">true</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">const</span> <span class="n">Instruction</span><span class="o">*</span> <span class="k">const</span> <span class="n">inst</span> <span class="o">=</span> <span class="n">next</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">dex_pc</span> <span class="o">=</span> <span class="n">inst</span><span class="o">-&gt;</span><span class="n">GetDexPc</span><span class="p">(</span><span class="n">insns</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">shadow_frame</span><span class="p">.</span><span class="n">SetDexPC</span><span class="p">(</span><span class="n">dex_pc</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">TraceExecution</span><span class="p">(</span><span class="n">shadow_frame</span><span class="p">,</span> <span class="n">inst</span><span class="p">,</span> <span class="n">dex_pc</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="kt">uint16_t</span> <span class="n">inst_data</span> <span class="o">=</span> <span class="n">inst</span><span class="o">-&gt;</span><span class="n">Fetch16</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span> <span class="c1">// 一条指令 4 字节
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">InstructionHandler</span><span class="p">(...).</span><span class="n">Preamble</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="k">switch</span> <span class="p">(</span><span class="n">inst</span><span class="o">-&gt;</span><span class="n">Opcode</span><span class="p">(</span><span class="n">inst_data</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">                <span class="k">case</span> <span class="nl">xxx</span><span class="p">:</span> <span class="p">...;</span>
</span></span><span class="line"><span class="cl">                <span class="k">case</span> <span class="nl">yyy</span><span class="p">:</span> <span class="p">...;</span>
</span></span><span class="line"><span class="cl">                <span class="p">...</span>
</span></span><span class="line"><span class="cl">            <span class="p">}</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>在当前版本中 (Android 12)，实际上是通过宏展开去定义了所有 op_code 的处理分支，不同版本实现都略有不同，但解释执行的核心思路从 Android 2.x 版本到现在都是一致的，因为字节码的定义并没有太多改变。</p>
<h3 id="快速执行" class="headerLink">
    <a href="#%e5%bf%ab%e9%80%9f%e6%89%a7%e8%a1%8c" class="header-mark"></a>快速执行</h3><p>再回到 ArtMethod 真正调用之前，如果不使用解释模式执行，则通过 <code>art_quick_invoke_stub</code> 去调用。stub 是一小段中间代码，用于跳转到实际的 native 执行，该符号使用汇编实现，在 ARM64 中的定义在 <em>art/runtime/arch/arm64/quick_entrypoints_arm64.S</em>，核心代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-57" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="p">.</span><span class="n">macro</span> <span class="n">INVOKE_STUB_CALL_AND_RETURN</span>
</span></span><span class="line"><span class="cl">    <span class="n">REFRESH_MARKING_REGISTER</span>
</span></span><span class="line"><span class="cl">    <span class="n">REFRESH_SUSPEND_CHECK_REGISTER</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// load method-&gt; METHOD_QUICK_CODE_OFFSET
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">ldr</span> <span class="n">x9</span><span class="p">,</span> <span class="p">[</span><span class="n">x0</span><span class="p">,</span> <span class="err">#</span><span class="n">ART_METHOD_QUICK_CODE_OFFSET_64</span><span class="p">]</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Branch to method.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">blr</span> <span class="n">x9</span>
</span></span><span class="line"><span class="cl"><span class="p">.</span><span class="n">endm</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="cm">/*
</span></span></span><span class="line"><span class="cl"><span class="cm"> *  extern&#34;C&#34; void art_quick_invoke_stub(ArtMethod *method,   x0
</span></span></span><span class="line"><span class="cl"><span class="cm"> *                                       uint32_t  *args,     x1
</span></span></span><span class="line"><span class="cl"><span class="cm"> *                                       uint32_t argsize,    w2
</span></span></span><span class="line"><span class="cl"><span class="cm"> *                                       Thread *self,        x3
</span></span></span><span class="line"><span class="cl"><span class="cm"> *                                       JValue *result,      x4
</span></span></span><span class="line"><span class="cl"><span class="cm"> *                                       char   *shorty);     x5
</span></span></span><span class="line"><span class="cl"><span class="cm"> */</span>
</span></span><span class="line"><span class="cl"><span class="n">ENTRY</span> <span class="n">art_quick_invoke_stub</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">INVOKE_STUB_CALL_AND_RETURN</span>
</span></span><span class="line"><span class="cl"><span class="n">END</span> <span class="n">art_quick_invoke_static_stub</span></span></span></code></pre>
</div>
<p>中间省略了一些保存上下文以及调用后恢复寄存器的代码，其核心是调用了 <code>ArtMethod</code> 结构体偏移 <code>ART_METHOD_QUICK_CODE_OFFSET_64</code> 处的指针，该值对应的代码为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-58" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">ASM_DEFINE</span><span class="p">(</span><span class="n">ART_METHOD_QUICK_CODE_OFFSET_64</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">           <span class="n">art</span><span class="o">::</span><span class="n">ArtMethod</span><span class="o">::</span><span class="n">EntryPointFromQuickCompiledCodeOffset</span><span class="p">(</span><span class="n">art</span><span class="o">::</span><span class="n">PointerSize</span><span class="o">::</span><span class="n">k64</span><span class="p">).</span><span class="n">Int32Value</span><span class="p">())</span></span></span></code></pre>
</div>
<p>即 <code>entry_point_from_quick_compiled_code_</code> 属性所指向的地址。</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-59" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">// art/runtime/art_method.h
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">static</span> <span class="k">constexpr</span> <span class="n">MemberOffset</span> <span class="nf">EntryPointFromQuickCompiledCodeOffset</span><span class="p">(</span><span class="n">PointerSize</span> <span class="n">pointer_size</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl"><span class="k">return</span> <span class="n">MemberOffset</span><span class="p">(</span><span class="n">PtrSizedFieldsOffset</span><span class="p">(</span><span class="n">pointer_size</span><span class="p">)</span> <span class="o">+</span> <span class="n">OFFSETOF_MEMBER</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="n">PtrSizedFields</span><span class="p">,</span> <span class="n">entry_point_from_quick_compiled_code_</span><span class="p">)</span> <span class="o">/</span> <span class="k">sizeof</span><span class="p">(</span><span class="kt">void</span><span class="o">*</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="o">*</span> <span class="k">static_cast</span><span class="o">&lt;</span><span class="n">size_t</span><span class="o">&gt;</span><span class="p">(</span><span class="n">pointer_size</span><span class="p">));</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>可以认为这就是所有快速模式执行代码的入口，至于该指针指向什么地方，又是什么时候初始化的，可以参考下一节代码加载部分。实际在方法调用时，快速模式执行的方法可能在其中执行到了需要以解释模式执行的方法，同样以解释模式执行的方法也可能在其中调用到 JNI 方法或者其他以快速模式执行的方法，所以在单个函数执行的过程中运行状态并不是一成不变的，但由于每次切换调用前后都保存和恢复了当前上下文，使得不同调用之间可以保持透明，这也是模块化设计的一大优势所在。</p>
<h2 id="代码加载" class="headerLink">
    <a href="#%e4%bb%a3%e7%a0%81%e5%8a%a0%e8%bd%bd" class="header-mark"></a>代码加载</h2><p>在上节我们知道在 ART 虚拟机中，Java 方法的调用主要通过 <code>ArtMethod::Invoke</code> 去实现，那么 ArtMethod 结构是什么时候创建的呢？为什么 jmethod/jobject 可以转换为 <code>ArtMethod</code> 指针呢？</p>
<p>在 Java 这门语言中，方法是需要依赖类而存在的，因此要分析方法的初始化需要先分析类的初始化。虽然我们前面知道如何从 OAT/VDEX/DEX 文件中构造对应的 ClassLoader 来进行类查找，但那个时候类并没有初始化，可以编写一个简单的类进行验证:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-60" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">public</span><span class="w"> </span><span class="kd">class</span> <span class="nc">Demo</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="kd">static</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">Log</span><span class="p">.</span><span class="na">i</span><span class="p">(</span><span class="s">&#34;Demo&#34;</span><span class="p">,</span><span class="w"> </span><span class="s">&#34;static block called&#34;</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">Log</span><span class="p">.</span><span class="na">i</span><span class="p">(</span><span class="s">&#34;Demo&#34;</span><span class="p">,</span><span class="w"> </span><span class="s">&#34;IIB called&#34;</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>如果 Demo 类在代码中没有使用，那么上述两个打印都不会触发；如果使用 <code>Class.forName(&quot;Demo&quot;)</code> 进行反射引用，则 static block 中的代码会被调用。跟踪 Class.forName 调用:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-61" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nd">@CallerSensitive</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="n">Class</span><span class="o">&lt;?&gt;</span><span class="w"> </span><span class="n">forName</span><span class="p">(</span><span class="n">String</span><span class="w"> </span><span class="n">className</span><span class="p">)</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="kd">throws</span><span class="w"> </span><span class="n">ClassNotFoundException</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">Class</span><span class="o">&lt;?&gt;</span><span class="w"> </span><span class="n">caller</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Reflection</span><span class="p">.</span><span class="na">getCallerClass</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="c1">// 笔者注: initialize = true</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">return</span><span class="w"> </span><span class="n">forName</span><span class="p">(</span><span class="n">className</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span><span class="n">ClassLoader</span><span class="p">.</span><span class="na">getClassLoader</span><span class="p">(</span><span class="n">caller</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>最终调用到名为 <code>classForName</code> 的 native 方法，其定义在 <em>art/runtime/native/java_lang_Class.cc</em>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-62" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="c1">// &#34;name&#34; is in &#34;binary name&#34; format, e.g. &#34;dalvik.system.Debug$1&#34;.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="k">static</span> <span class="n">jclass</span> <span class="nf">Class_classForName</span><span class="p">(</span><span class="n">JNIEnv</span><span class="o">*</span> <span class="n">env</span><span class="p">,</span> <span class="n">jclass</span><span class="p">,</span> <span class="n">jstring</span> <span class="n">javaName</span><span class="p">,</span> <span class="n">jboolean</span> <span class="n">initialize</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                 <span class="n">jobject</span> <span class="n">javaLoader</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ScopedFastNativeObjectAccess</span> <span class="n">soa</span><span class="p">(</span><span class="n">env</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">ScopedUtfChars</span> <span class="n">name</span><span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">javaName</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">descriptor</span><span class="p">(</span><span class="n">DotToDescriptor</span><span class="p">(</span><span class="n">name</span><span class="p">.</span><span class="n">c_str</span><span class="p">()));</span>
</span></span><span class="line"><span class="cl">    <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span> <span class="n">class_loader</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">      <span class="n">hs</span><span class="p">.</span><span class="n">NewHandle</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Decode</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span><span class="p">(</span><span class="n">javaLoader</span><span class="p">)));</span>
</span></span><span class="line"><span class="cl">    <span class="n">ClassLinker</span><span class="o">*</span> <span class="n">class_linker</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetClassLinker</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">c</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">      <span class="n">hs</span><span class="p">.</span><span class="n">NewHandle</span><span class="p">(</span><span class="n">class_linker</span><span class="o">-&gt;</span><span class="n">FindClass</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Self</span><span class="p">(),</span> <span class="n">descriptor</span><span class="p">.</span><span class="n">c_str</span><span class="p">(),</span> <span class="n">class_loader</span><span class="p">)));</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">initialize</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">class_linker</span><span class="o">-&gt;</span><span class="n">EnsureInitialized</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Self</span><span class="p">(),</span> <span class="n">c</span><span class="p">,</span> <span class="nb">true</span><span class="p">,</span> <span class="nb">true</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">soa</span><span class="p">.</span><span class="n">AddLocalReference</span><span class="o">&lt;</span><span class="n">jclass</span><span class="o">&gt;</span><span class="p">(</span><span class="n">c</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>首先将 Java 格式的类表示转换为 smali 格式，然后通过指定的 class_loader 去查找类，查找过程主要通过 <code>class_linker</code> 实现。由于 forName 函数中指定了 <code>initialize</code> 为 <code>true</code>，因此在找到对应类后还会额外执行一步 <code>EnsureInitialized</code>，在后文会进行详细介绍。</p>
<h3 id="findclass" class="headerLink">
    <a href="#findclass" class="header-mark"></a>FindClass</h3><p>FindClass 实现了根据类名查找类的过程，定义在 <em>art/runtime/class_linker.cc</em> 中，关键流程如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
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    <button 
      class="
        code-block-button
        tw-mx-2 
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        tw-flex-row
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      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
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        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
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        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-63" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">ClassLinker</span><span class="o">::</span><span class="n">FindClass</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                             <span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">descriptor</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                             <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span> <span class="n">class_loader</span><span class="p">)</span> 
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">descriptor</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="sc">&#39;\0&#39;</span><span class="p">)</span> 
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">FindPrimitiveClass</span><span class="p">(</span><span class="n">descriptor</span><span class="p">[</span><span class="mi">0</span><span class="p">]);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">size_t</span> <span class="n">hash</span> <span class="o">=</span> <span class="n">ComputeModifiedUtf8Hash</span><span class="p">(</span><span class="n">descriptor</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// 在已经加载的类中查找
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">klass</span> <span class="o">=</span> <span class="n">LookupClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span> <span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">klass</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nf">EnsureResolved</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">klass</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// 尚未加载
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">descriptor</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">!=</span> <span class="sc">&#39;[&#39;</span> <span class="o">&amp;&amp;</span> <span class="n">class_loader</span> <span class="o">==</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// 类加载器为空，且不是数组类型，在启动类中进行查找
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">ClassPathEntry</span> <span class="n">pair</span> <span class="o">=</span> <span class="n">FindInClassPath</span><span class="p">(</span><span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span> <span class="n">boot_class_path_</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nf">DefineClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                           <span class="n">ScopedNullHandle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">                           <span class="o">*</span><span class="n">pair</span><span class="p">.</span><span class="n">first</span><span class="p">,</span> <span class="o">*</span><span class="n">pair</span><span class="p">.</span><span class="n">second</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">result_ptr</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kt">bool</span> <span class="n">descriptor_equals</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">ScopedObjectAccessUnchecked</span> <span class="nf">soa</span><span class="p">(</span><span class="n">self</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// 先通过 classLoader 的父类查找
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kt">bool</span> <span class="n">known_hierarchy</span> <span class="o">=</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInBaseDexClassLoader</span><span class="p">(</span><span class="n">soa</span><span class="p">,</span> <span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span> <span class="n">class_loader</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">result_ptr</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">result_ptr</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">descriptor_equals</span> <span class="o">=</span> <span class="nb">true</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="nf">if</span> <span class="p">(</span><span class="o">!</span><span class="n">self</span><span class="o">-&gt;</span><span class="n">IsExceptionPending</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// 如果没找到，再通过 classLoader 查找
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">class_name_string</span><span class="p">(</span><span class="n">descriptor</span> <span class="o">+</span> <span class="mi">1</span><span class="p">,</span> <span class="n">descriptor_length</span> <span class="o">-</span> <span class="mi">2</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">std</span><span class="o">::</span><span class="n">replace</span><span class="p">(</span><span class="n">class_name_string</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span> <span class="n">class_name_string</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span> <span class="sc">&#39;/&#39;</span><span class="p">,</span> <span class="sc">&#39;.&#39;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">ScopedLocalRef</span><span class="o">&lt;</span><span class="n">jobject</span><span class="o">&gt;</span> <span class="n">class_loader_object</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">            <span class="n">soa</span><span class="p">.</span><span class="n">Env</span><span class="p">(),</span> <span class="n">soa</span><span class="p">.</span><span class="n">AddLocalReference</span><span class="o">&lt;</span><span class="n">jobject</span><span class="o">&gt;</span><span class="p">(</span><span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">()));</span>
</span></span><span class="line"><span class="cl">        <span class="n">ScopedLocalRef</span><span class="o">&lt;</span><span class="n">jobject</span><span class="o">&gt;</span> <span class="n">result</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Env</span><span class="p">(),</span> <span class="k">nullptr</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">result</span><span class="p">.</span><span class="n">reset</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Env</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">CallObjectMethod</span><span class="p">(</span><span class="n">class_loader_object</span><span class="p">.</span><span class="n">get</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">                                                 <span class="n">WellKnownClasses</span><span class="o">::</span><span class="n">java_lang_ClassLoader_loadClass</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                 <span class="n">class_name_object</span><span class="p">.</span><span class="n">get</span><span class="p">()));</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 将找到的类插入到缓存表中
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">ClassTable</span><span class="o">*</span> <span class="k">const</span> <span class="n">class_table</span> <span class="o">=</span> <span class="n">InsertClassTableForClassLoader</span><span class="p">(</span><span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="n">class_table</span><span class="o">-&gt;</span><span class="n">InsertWithHash</span><span class="p">(</span><span class="n">result_ptr</span><span class="p">,</span> <span class="n">hash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">result_ptr</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>首先会通过 <code>LookupClass</code> 在已经加载的类中查找，已经加载的类会保存在 ClassTable 中，以 hash 表的方式存储，该表的键就是类对应的 hash，通过 descriptor 计算得出。如果之前已经加载过，那么这时候就可以直接返回，如果没有就需要执行真正的加载了。从这里我们也可以看出，类的加载过程属于懒加载 (lazy loading)，如果一个类不曾被使用，那么是不会有任何加载开销的。</p>
<p>然后会判断指定的类加载器是否为空，为空表示要查找的类实际上是一个系统类。系统类不存在于 APP 的 DEX 文件中，而是 Android 系统的一部分。由于每个 Android (Java) 应用都会用到系统类，为了提高启动速度，实际通过 zygote 去加载，并由所有子进程一起共享。上述 <code>boot_class_path_</code> 数组在 <code>Runtime::Init</code> 中通过 ART 启动的参数进行初始化，感兴趣的可以自行研究细节。</p>
<p>我们关心的应用类查找过程可以分为两步，首先在父类的 ClassLoader 进行查找，如果没找到才会通过指定的 classLoader 进行查找，这也是很多类似 Java 文章中提到的 “双亲委派” 机制。保证关键类的查找过程优先通过系统类加载器，可以防止关键类实现被应用篡改。</p>
<p><code>FindClassInBaseDexClassLoader</code> 的实现使用伪代码描述如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-64" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">Class</span> <span class="n">ClassLinker</span><span class="o">::</span><span class="n">FindClassInBaseDexClassLoader</span><span class="p">(</span><span class="n">ClassLoader</span> <span class="n">class_loader</span><span class="p">,</span> <span class="n">size_t</span> <span class="n">hash</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">class_loader</span> <span class="o">==</span> <span class="n">java_lang_BootClassLoader</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nf">FindClassInBootClassLoaderClassPath</span><span class="p">(</span><span class="n">class_loader</span><span class="p">,</span> <span class="n">hash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">class_loader</span> <span class="o">==</span> <span class="n">dalvik_system_PathClassLoader</span> <span class="o">||</span>
</span></span><span class="line"><span class="cl">        <span class="n">class_loader</span> <span class="o">==</span> <span class="n">dalvik_system_DexClassLoader</span> <span class="o">||</span>
</span></span><span class="line"><span class="cl">        <span class="n">class_loader</span> <span class="o">==</span> <span class="n">dalvik_system_InMemoryDexClassLoader</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// For regular path or dex class loader the search order is:
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - parent
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - shared libraries
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - class loader dex files
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">FindClassInBaseDexClassLoader</span><span class="p">(</span><span class="n">class_loader</span><span class="o">-&gt;</span><span class="n">GetParent</span><span class="p">,</span> <span class="n">hash</span><span class="p">)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInSharedLibraries</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInBaseDexClassLoaderClassPath</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInSharedLibrariesAfter</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">class_loader</span> <span class="o">==</span> <span class="n">dalvik_system_DelegateLastClassLoader</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// For delegate last, the search order is:
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - boot class path
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - shared libraries
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - class loader dex files
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="c1">//    - parent
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">FindClassInBootClassLoaderClassPath</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInBaseDexClassLoaderClassPath</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInSharedLibrariesAfter</span><span class="p">(...)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="n">FindClassInBaseDexClassLoader</span><span class="p">(</span><span class="n">class_loader</span><span class="o">-&gt;</span><span class="n">GetParent</span><span class="p">,</span> <span class="n">hash</span><span class="p">)</span> <span class="o">&amp;&amp;</span> <span class="k">return</span> <span class="n">result</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">null</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>根据不同的 class_loader 类型使用不同的搜索顺序，如果涉及到父 ClassLoader 的搜索，则使用递归查找，递归的停止条件是当前 class_loader 为<code>java.lang.BootClassLoader</code>。</p>
<p><code>FindClassInBootClassLoaderClassPath</code> 的关键代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-65" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">using</span> <span class="n">ClassPathEntry</span> <span class="o">=</span> <span class="n">std</span><span class="o">::</span><span class="n">pair</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">*</span><span class="p">,</span> <span class="k">const</span> <span class="n">dex</span><span class="o">::</span><span class="n">ClassDef</span><span class="o">*&gt;</span><span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="kt">bool</span> <span class="n">ClassLinker</span><span class="o">::</span><span class="n">FindClassInBootClassLoaderClassPath</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                      <span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">descriptor</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                      <span class="n">size_t</span> <span class="n">hash</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                      <span class="cm">/*out*/</span> <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;*</span> <span class="n">result</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ClassPathEntry</span> <span class="n">pair</span> <span class="o">=</span> <span class="n">FindInClassPath</span><span class="p">(</span><span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span> <span class="n">boot_class_path_</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">pair</span><span class="p">.</span><span class="n">second</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">klass</span> <span class="o">=</span> <span class="n">LookupClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">hash</span><span class="p">,</span> <span class="k">nullptr</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="n">klass</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="o">*</span><span class="n">result</span> <span class="o">=</span> <span class="n">EnsureResolved</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">klass</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="o">*</span><span class="n">result</span> <span class="o">=</span> <span class="n">DefineClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="p">...);</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="nb">true</span><span class="p">;</span></span></span></code></pre>
</div>
<p>如果在 BaseClassLoader 中没有找到对应的类，那么最终会通过传入的 classLoader 查找，即调用指定类加载器的 loadClass 方法。在这个场景中(Class.forName)，实际指定的是 caller 的 classLoader，编写一个 APK 进行动态分析，打印出当前的 classLoader 如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-66" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>dalvik.system.PathClassLoader[
DexPathList[[
zip file &#34;/data/app/~~0FBqwacokhdG5rhF1RDZGg==/com.evilpan.test-fCJvsE74xP_SdvTlAfJDcA==/base.apk&#34;
],
nativeLibraryDirectories=[/data/app/~~0FBqwacokhdG5rhF1RDZGg==/com.evilpan.test-fCJvsE74xP_SdvTlAfJDcA==/lib/arm64, /system/lib64, /system_ext/lib64]]]</code></pre></code></pre>
</div>
<p>所以这是一个 <code>PathClassLoader</code> 对象，该类没有定义 loadClass，因此是调用了父类的 loadClass 方法，整体调用路径如下所示:</p>
<pre class="mermaid">sequenceDiagram
%% loadClass
participant P as PathClassLoader
participant B as BaseDexClassLoader
participant C as ClassLoader
participant D as DexFile
P ->> C: loadClass
C ->> B: findClass
B ->> P: pathList.findClass
P ->> D: loadClassBinaryName
Note right of D: defineClass <br> defineClassNative
</pre><p><figure><a class="lightgallery" href="/img/2021-12-26-art-internal/0.png" title="img-load" data-thumbnail="/img/2021-12-26-art-internal/0.png" data-sub-html="<h2>loadClass</h2><p>img-load</p>"><img  loading="lazy" src='/img/2021-12-26-art-internal/0.png'   alt="img-load"  ></a><figcaption class="image-caption">loadClass</figcaption>
</figure></p>
<p>最终调用了 DexFile 的 native 方法 defineClassNative，实现在 <em>art/runtime/native/dalvik_system_DexFile.cc</em>，关键代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-67" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="n">jclass</span> <span class="nf">DexFile_defineClassNative</span><span class="p">(</span><span class="n">JNIEnv</span><span class="o">*</span> <span class="n">env</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                        <span class="n">jclass</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                        <span class="n">jstring</span> <span class="n">javaName</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                        <span class="n">jobject</span> <span class="n">javaLoader</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                        <span class="n">jobject</span> <span class="n">cookie</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                        <span class="n">jobject</span> <span class="n">dexFile</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">std</span><span class="o">::</span><span class="n">vector</span><span class="o">&lt;</span><span class="k">const</span> <span class="n">DexFile</span><span class="o">*&gt;</span> <span class="n">dex_files</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="n">ConvertJavaArrayToDexFiles</span><span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">cookie</span><span class="p">,</span> <span class="cm">/*out*/</span> <span class="n">dex_files</span><span class="p">,</span> <span class="cm">/*out*/</span> <span class="n">oat_file</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">ScopedUtfChars</span> <span class="n">class_name</span><span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">javaName</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">std</span><span class="o">::</span><span class="n">string</span> <span class="n">descriptor</span><span class="p">(</span><span class="n">DotToDescriptor</span><span class="p">(</span><span class="n">class_name</span><span class="p">.</span><span class="n">c_str</span><span class="p">()));</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="n">size_t</span> <span class="n">hash</span><span class="p">(</span><span class="n">ComputeModifiedUtf8Hash</span><span class="p">(</span><span class="n">descriptor</span><span class="p">.</span><span class="n">c_str</span><span class="p">()));</span>
</span></span><span class="line"><span class="cl">    <span class="k">for</span> <span class="p">(</span><span class="k">auto</span><span class="o">&amp;</span> <span class="nl">dex_file</span> <span class="p">:</span> <span class="n">dex_files</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">const</span> <span class="n">dex</span><span class="o">::</span><span class="n">ClassDef</span><span class="o">*</span> <span class="n">dex_class_def</span> <span class="o">=</span> <span class="n">OatDexFile</span><span class="o">::</span><span class="n">FindClassDef</span><span class="p">(</span><span class="o">*</span><span class="n">dex_file</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">.</span><span class="n">c_str</span><span class="p">(),</span> <span class="n">hash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// dex_class_def != nullptr
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">ClassLinker</span><span class="o">*</span> <span class="n">class_linker</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetClassLinker</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">        <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span> <span class="n">class_loader</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">          <span class="n">hs</span><span class="p">.</span><span class="n">NewHandle</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Decode</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span><span class="p">(</span><span class="n">javaLoader</span><span class="p">)));</span>
</span></span><span class="line"><span class="cl">        <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">DexCache</span><span class="o">&gt;</span> <span class="n">dex_cache</span> <span class="o">=</span>
</span></span><span class="line"><span class="cl">          <span class="n">class_linker</span><span class="o">-&gt;</span><span class="n">RegisterDexFile</span><span class="p">(</span><span class="o">*</span><span class="n">dex_file</span><span class="p">,</span> <span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// dex_cache != nullptr
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">result</span> <span class="o">=</span> <span class="n">class_linker</span><span class="o">-&gt;</span><span class="n">DefineClass</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Self</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">                                                               <span class="n">descriptor</span><span class="p">.</span><span class="n">c_str</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">                                                               <span class="n">hash</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                               <span class="n">class_loader</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                               <span class="o">*</span><span class="n">dex_file</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                                               <span class="o">*</span><span class="n">dex_class_def</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">class_linker</span><span class="o">-&gt;</span><span class="n">InsertDexFileInToClassLoader</span><span class="p">(</span><span class="n">soa</span><span class="p">.</span><span class="n">Decode</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Object</span><span class="o">&gt;</span><span class="p">(</span><span class="n">dexFile</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">                                                 <span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>也就是说，不论是通过 <code>FindClassInBaseDexClassLoader</code> 查找还是通过指定 classLoader 的 <code>loadClass</code> 加载，最终执行的流程都是类似的，即在对应的 DexFile(OatDexFile) 中根据类名搜索对应类的 ClassDef 字段，了解 Dex 文件结构的对这个字段应该不会陌生，后面可能会单独写一篇 DexFile 文件格式的介绍，这里限于篇幅先不展开，只需要知道这个字段包含类的定义即可。</p>
<p>在找到类在对应 Dex 文件中的 ClassDef 内容后，会通过 ClassLinker 完成该类的后续注册流程，包括:</p>
<ul>
<li>对于当前 DexFile，如果是第一次遇到，会创建一个 DexCache 缓存，保存到 ClassLinker 的 <code>dex_caches_</code> 哈希表中；</li>
<li>通过 <code>ClassLinker::DefineClass</code> 完成目标类的定义，详见后文；</li>
<li>将对应 DexFile 添加到类加载器对应的 ClassTable 中；</li>
</ul>
<p>其中 DefineClass 是我们比较关心的，因此下面单独进行介绍。</p>
<h3 id="defineclass" class="headerLink">
    <a href="#defineclass" class="header-mark"></a>DefineClass</h3><p>先看代码:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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          <p class="tw-select-none !tw-my-1">cpp</p>
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        class="
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

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        class="
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        class="
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          tw-mx-2 
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          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-68" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">ClassLinker</span><span class="o">::</span><span class="n">DefineClass</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                               <span class="k">const</span> <span class="kt">char</span><span class="o">*</span> <span class="n">descriptor</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                               <span class="n">size_t</span> <span class="n">hash</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                               <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">ClassLoader</span><span class="o">&gt;</span> <span class="n">class_loader</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                               <span class="k">const</span> <span class="n">DexFile</span><span class="o">&amp;</span> <span class="n">dex_file</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                               <span class="k">const</span> <span class="n">dex</span><span class="o">::</span><span class="n">ClassDef</span><span class="o">&amp;</span> <span class="n">dex_class_def</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ScopedDefiningClass</span> <span class="nf">sdc</span><span class="p">(</span><span class="n">self</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">StackHandleScope</span><span class="o">&lt;</span><span class="mi">3</span><span class="o">&gt;</span> <span class="n">hs</span><span class="p">(</span><span class="n">self</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">auto</span> <span class="n">klass</span> <span class="o">=</span> <span class="n">hs</span><span class="p">.</span><span class="n">NewHandle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span><span class="p">(</span><span class="k">nullptr</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// Load the class from the dex file.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="o">!</span><span class="n">init_done_</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// [1] finish up init of hand crafted class_roots_
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">DexCache</span><span class="o">&gt;</span> <span class="n">dex_cache</span> <span class="o">=</span> <span class="n">RegisterDexFile</span><span class="p">(</span><span class="o">*</span><span class="n">new_dex_file</span><span class="p">,</span> <span class="n">class_loader</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="n">klass</span><span class="o">-&gt;</span><span class="n">SetDexCache</span><span class="p">(</span><span class="n">dex_cache</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">ObjPtr</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">existing</span> <span class="o">=</span> <span class="n">InsertClass</span><span class="p">(</span><span class="n">descriptor</span><span class="p">,</span> <span class="n">klass</span><span class="p">.</span><span class="n">Get</span><span class="p">(),</span> <span class="n">hash</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">existing</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// 其他线程正在链接该类，阻塞等待其完成
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="k">return</span> <span class="n">sdc</span><span class="p">.</span><span class="n">Finish</span><span class="p">(</span><span class="n">EnsureResolved</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">existing</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">LoadClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="o">*</span><span class="n">new_dex_file</span><span class="p">,</span> <span class="o">*</span><span class="n">new_class_def</span><span class="p">,</span> <span class="n">klass</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// klass-&gt;IsLoaded
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">LoadSuperAndInterfaces</span><span class="p">(</span><span class="n">klass</span><span class="p">,</span> <span class="o">*</span><span class="n">new_dex_file</span><span class="p">))</span>
</span></span><span class="line"><span class="cl">    <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetRuntimeCallbacks</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">ClassLoad</span><span class="p">(</span><span class="n">klass</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// klass-&gt;IsResolved
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">LinkClass</span><span class="p">(</span><span class="n">self</span><span class="p">,</span> <span class="n">descriptor</span><span class="p">,</span> <span class="n">klass</span><span class="p">,</span> <span class="n">interfaces</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">h_new_class</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">GetRuntimeCallbacks</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">ClassPrepare</span><span class="p">(</span><span class="n">klass</span><span class="p">,</span> <span class="n">h_new_class</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="n">jit</span><span class="o">::</span><span class="n">Jit</span><span class="o">::</span><span class="n">NewTypeLoadedIfUsingJit</span><span class="p">(</span><span class="n">h_new_class</span><span class="p">.</span><span class="n">Get</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">sdc</span><span class="p">.</span><span class="n">Finish</span><span class="p">(</span><span class="n">h_new_class</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>这里只列出一些关键代码，<code>init_done_</code> 用于表示当前 ClassLinker 的初始化状态，初始化过程用于从 Image 空间或者手动创建内部类，手动创建的内部类包括:</p>
<ul>
<li>Ljava/lang/Object;</li>
<li>Ljava/lang/Class;</li>
<li>Ljava/lang/String;</li>
<li>Ljava/lang/ref/Reference;</li>
<li>Ljava/lang/DexCache;</li>
<li>Ldalvik/system/ClassExt;</li>
</ul>
<p>它们都直接定义在了 <code>art::runtime::mirror</code> 命名空间中，比如 Object 定义为 <code>mirror::Object</code>，所属文件为 <em>art/runtime/mirror/object.h</em> ；</p>
<h3 id="loadclass" class="headerLink">
    <a href="#loadclass" class="header-mark"></a>LoadClass</h3><p><code>ClassLinker::LoadClass</code> 用于从指定 DEX 文件中加载目标类的属性和方法等内容，注意这里其实是在对应类添加到 ClassTable 之后才加载的，这是出于 ART 的内部优化考虑，另外一个原因是类的属性根只能通过 ClassTable 访问，因此需要在访问前先在 ClassTable 中占好位置。其实现如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-69" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
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      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">ClassLinker</span><span class="o">::</span><span class="n">LoadClass</span><span class="p">(</span><span class="n">Thread</span><span class="o">*</span> <span class="n">self</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                            <span class="k">const</span> <span class="n">DexFile</span><span class="o">&amp;</span> <span class="n">dex_file</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                            <span class="k">const</span> <span class="n">dex</span><span class="o">::</span><span class="n">ClassDef</span><span class="o">&amp;</span> <span class="n">dex_class_def</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                            <span class="n">Handle</span><span class="o">&lt;</span><span class="n">mirror</span><span class="o">::</span><span class="n">Class</span><span class="o">&gt;</span> <span class="n">klass</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">ClassAccessor</span> <span class="nf">accessor</span><span class="p">(</span><span class="n">dex_file</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                         <span class="n">dex_class_def</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                         <span class="cm">/* parse_hiddenapi_class_data= */</span> <span class="n">klass</span><span class="o">-&gt;</span><span class="n">IsBootStrapClassLoaded</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="n">Runtime</span><span class="o">*</span> <span class="k">const</span> <span class="n">runtime</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="n">accessor</span><span class="p">.</span><span class="n">VisitFieldsAndMethods</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="p">[</span><span class="o">&amp;</span><span class="p">](</span><span class="k">const</span> <span class="n">ClassAccessor</span><span class="o">::</span><span class="n">Field</span><span class="o">&amp;</span> <span class="n">field</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">LoadField</span><span class="p">(</span><span class="n">field</span><span class="p">,</span> <span class="n">klass</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">sfields</span><span class="o">-&gt;</span><span class="n">At</span><span class="p">(</span><span class="n">num_sfields</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">            <span class="o">++</span><span class="n">num_sfields</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="p">[</span><span class="o">&amp;</span><span class="p">](</span><span class="k">const</span> <span class="n">ClassAccessor</span><span class="o">::</span><span class="n">Field</span><span class="o">&amp;</span> <span class="n">field</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">LoadField</span><span class="p">(</span><span class="n">field</span><span class="p">,</span> <span class="n">klass</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">ifields</span><span class="o">-&gt;</span><span class="n">At</span><span class="p">(</span><span class="n">num_ifields</span><span class="p">));</span>
</span></span><span class="line"><span class="cl">            <span class="o">++</span><span class="n">num_ifields</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="p">[</span><span class="o">&amp;</span><span class="p">](</span><span class="k">const</span> <span class="n">ClassAccessor</span><span class="o">::</span><span class="n">Method</span><span class="o">&amp;</span> <span class="n">method</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">ArtMethod</span><span class="o">*</span> <span class="n">art_method</span> <span class="o">=</span> <span class="n">klass</span><span class="o">-&gt;</span><span class="n">GetDirectMethodUnchecked</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">                <span class="n">class_def_method_index</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                <span class="n">image_pointer_size_</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="n">LoadMethod</span><span class="p">(</span><span class="n">dex_file</span><span class="p">,</span> <span class="n">method</span><span class="p">,</span> <span class="n">klass</span><span class="p">,</span> <span class="n">art_method</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="n">LinkCode</span><span class="p">(</span><span class="k">this</span><span class="p">,</span> <span class="n">art_method</span><span class="p">,</span> <span class="n">oat_class_ptr</span><span class="p">,</span> <span class="n">class_def_method_index</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="o">++</span><span class="n">class_def_method_index</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="p">[</span><span class="o">&amp;</span><span class="p">](</span><span class="k">const</span> <span class="n">ClassAccessor</span><span class="o">::</span><span class="n">Method</span><span class="o">&amp;</span> <span class="n">method</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">ArtMethod</span><span class="o">*</span> <span class="n">art_method</span> <span class="o">=</span> <span class="n">klass</span><span class="o">-&gt;</span><span class="n">GetVirtualMethodUnchecked</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">                <span class="n">class_def_method_index</span> <span class="o">-</span> <span class="n">accessor</span><span class="p">.</span><span class="n">NumDirectMethods</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">                <span class="n">image_pointer_size_</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="n">LoadMethod</span><span class="p">(</span><span class="n">dex_file</span><span class="p">,</span> <span class="n">method</span><span class="p">,</span> <span class="n">klass</span><span class="p">,</span> <span class="n">art_method</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="n">LinkCode</span><span class="p">(</span><span class="k">this</span><span class="p">,</span> <span class="n">art_method</span><span class="p">,</span> <span class="n">oat_class_ptr</span><span class="p">,</span> <span class="n">class_def_method_index</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">            <span class="o">++</span><span class="n">class_def_method_index</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">klass</span><span class="o">-&gt;</span><span class="n">SetSFieldsPtr</span><span class="p">(</span><span class="n">sfields</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="n">klass</span><span class="o">-&gt;</span><span class="n">SetIFieldsPtr</span><span class="p">(</span><span class="n">ifields</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>上面用到了 <code>C++11</code> 的 lambda 函数来通过迭代器访问类中的关联元素，分别是:</p>
<ol>
<li>sfields: static fields，静态属性</li>
<li>ifields: instance fields，对象属性</li>
<li>direct method: 对象方法</li>
<li>virtual method: 抽象方法</li>
</ol>
<p>对于属性的加载通过 <code>LoadField</code> 实现，主要作用是初始化 ArtField 并与目标类关联起来；<code>LoadMethod</code> 的实现亦是类似，主要是使用 dex 文件中对应方法的 CodeItem 对 ArtMethod 进行初始化，并与 klass 关联。但是对于方法而言，还好进行额外的一步，即 <code>LinkCode</code>。</p>
<h3 id="linkcode" class="headerLink">
    <a href="#linkcode" class="header-mark"></a>LinkCode</h3><p>LinkCode 顾名思义是对代码进行链接，关键代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-70" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="kt">void</span> <span class="nf">LinkCode</span><span class="p">(</span><span class="n">ClassLinker</span><span class="o">*</span> <span class="n">class_linker</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                     <span class="n">ArtMethod</span><span class="o">*</span> <span class="n">method</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                     <span class="k">const</span> <span class="n">OatFile</span><span class="o">::</span><span class="n">OatClass</span><span class="o">*</span> <span class="n">oat_class</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                     <span class="kt">uint32_t</span> <span class="n">class_def_method_index</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">Runtime</span><span class="o">*</span> <span class="k">const</span> <span class="n">runtime</span> <span class="o">=</span> <span class="n">Runtime</span><span class="o">::</span><span class="n">Current</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_code</span> <span class="o">=</span> <span class="k">nullptr</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">oat_class</span> <span class="o">!=</span> <span class="k">nullptr</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">         <span class="c1">// Every kind of method should at least get an invoke stub from the oat_method.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>         <span class="c1">// non-abstract methods also get their code pointers.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>         <span class="k">const</span> <span class="n">OatFile</span><span class="o">::</span><span class="n">OatMethod</span> <span class="n">oat_method</span> <span class="o">=</span> <span class="n">oat_class</span><span class="o">-&gt;</span><span class="n">GetOatMethod</span><span class="p">(</span><span class="n">class_def_method_index</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">         <span class="n">quick_code</span> <span class="o">=</span> <span class="n">oat_method</span><span class="p">.</span><span class="n">GetQuickCode</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="n">runtime</span><span class="o">-&gt;</span><span class="n">GetInstrumentation</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">InitializeMethodsCode</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">quick_code</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Set up the dlsym lookup stub. Do not go through `UnregisterNative()`
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// as the extra processing for @CriticalNative is not needed yet.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="n">method</span><span class="o">-&gt;</span><span class="n">SetEntryPointFromJni</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">            <span class="n">method</span><span class="o">-&gt;</span><span class="n">IsCriticalNative</span><span class="p">()</span> <span class="o">?</span> <span class="n">GetJniDlsymLookupCriticalStub</span><span class="p">()</span> <span class="o">:</span> <span class="n">GetJniDlsymLookupStub</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中 quick_code 指针指向的是 OatMethod 中的 <code>code_offset_</code> 偏移处的值，该值指向的是 OAT 优化后的本地代码位置。<code>InitializeMethodsCode</code> 是 <code>Instrumentation</code> 类的方法，实现在 <em>art/runtime/instrumentation.cc</em>，如果看过之前分析应用启动流程的文章应该对这个类不会陌生，尽管不是同一个类，但它们的功能却是类似的，即作为某些关键调用的收口，并在其中实现可插拔的追踪行为。其内部实现如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
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        class="
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          hover:tw-text-fgColor-link 
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        title="Copy code">
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-71" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="n">Instrumentation</span><span class="o">::</span><span class="n">InitializeMethodsCode</span><span class="p">(</span><span class="n">ArtMethod</span><span class="o">*</span> <span class="n">method</span><span class="p">,</span> <span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">aot_code</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Use instrumentation entrypoints if instrumentation is installed.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="n">EntryExitStubsInstalled</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="n">InterpretOnly</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">UpdateEntryPoints</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">GetQuickToInterpreterBridge</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">UpdateEntryPoints</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">GetQuickInstrumentationEntryPoint</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">        <span class="p">}</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="n">IsForcedInterpretOnly</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">UpdateEntryPoints</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">            <span class="n">method</span><span class="p">,</span> <span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">?</span> <span class="n">GetQuickGenericJniStub</span><span class="p">()</span> <span class="o">:</span> <span class="n">GetQuickToInterpreterBridge</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Use the provided AOT code if possible.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">CanUseAotCode</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">aot_code</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">UpdateEntryPoints</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">aot_code</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// Use default entrypoints.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="n">UpdateEntryPoints</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">      <span class="n">method</span><span class="p">,</span> <span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">?</span> <span class="n">GetQuickGenericJniStub</span><span class="p">()</span> <span class="o">:</span> <span class="n">GetQuickToInterpreterBridge</span><span class="p">());</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>第一部分正是用于追踪的判断，如果当前已经安装了追踪监控，那么会根据当前方法的类别分别设置对应的入口点；否则就以常规方式设置方法的调用入口:</p>
<ul>
<li>对于强制解释执行的运行时环境:
<ul>
<li>如果是 Native 方法则将入口点设置为 <code>art_quick_generic_jni_trampoline</code>，用于跳转执行 JNI 本地代码；</li>
<li>对于 Java 方法则将入口点设置为 <code>art_quick_to_interpreter_bridge</code>，使方法调用过程会跳转到解释器继续；</li>
</ul>
</li>
<li>如果 AOT 编译的本地代码可用，则直接将方法入口点设置为 AOT 代码；</li>
<li>如果 AOT 代码不可用，那么就回到解释执行场景进行处理；</li>
</ul>
<p>设置 ArtMethod 入口地址的方法是 UpdateEntryPoints，其内部实现非常简单:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

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        class="
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        class="
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  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-72" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">static</span> <span class="kt">void</span> <span class="nf">UpdateEntryPoints</span><span class="p">(</span><span class="n">ArtMethod</span><span class="o">*</span> <span class="n">method</span><span class="p">,</span> <span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">quick_code</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">REQUIRES_SHARED</span><span class="p">(</span><span class="n">Locks</span><span class="o">::</span><span class="n">mutator_lock_</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="n">kIsDebugBuild</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="p">...</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// If the method is from a boot image, don&#39;t dirty it if the entrypoint
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="c1">// doesn&#39;t change.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">GetEntryPointFromQuickCompiledCode</span><span class="p">()</span> <span class="o">!=</span> <span class="n">quick_code</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">method</span><span class="o">-&gt;</span><span class="n">SetEntryPointFromQuickCompiledCode</span><span class="p">(</span><span class="n">quick_code</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>内部实质上是调用了 <code>ArtMethod::SetEntryPointFromQuickCompiledCode</code>:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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    tw-flex 
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
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          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-73" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span> <span class="nf">SetEntryPointFromQuickCompiledCode</span><span class="p">(</span><span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">entry_point_from_quick_compiled_code</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">      <span class="n">REQUIRES_SHARED</span><span class="p">(</span><span class="n">Locks</span><span class="o">::</span><span class="n">mutator_lock_</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">SetEntryPointFromQuickCompiledCodePtrSize</span><span class="p">(</span><span class="n">entry_point_from_quick_compiled_code</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">                                              <span class="n">kRuntimePointerSize</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span></span></span></code></pre>
</div>
<p>回顾我们前面分析方法调用的章节，对于快速执行的场景，<code>ArtMethod::Invoke</code> 最终是跳转到  <code>entry_point_from_quick_compiled_code</code> 进行执行，而这个字段就是在这里进行设置的。</p>
<p>至此，我们完成了 ART 方法调用流程分析的最后一块拼图。</p>
<h3 id="类初始化" class="headerLink">
    <a href="#%e7%b1%bb%e5%88%9d%e5%a7%8b%e5%8c%96" class="header-mark"></a>类初始化</h3><p>此时我们已经完成了类的加载，包括类中的所有方法、属性的初始化。在前文 <code>classForName</code> 的实现中，完成类加载后还调用了一次 EnsureInitialized，在其中调用了 <code>ClassLinker::InitializeClass</code> 对类进行初始化，主要包括静态属性的初始化以及调用类中的 <code>&lt;clinit&gt;</code> 代码，这也是为什么本节开头 Demo 类的 static block 中代码会被调用的原因。</p>
<blockquote>
  <p>初始化流程严格按照 Java 语言标准实现，详见 <a href="https://docs.oracle.com/javase/specs/jls/se7/html/jls-12.html#jls-12.4" target="_blank" rel="noopener noreferrer">Java Language Specification 12.4.2 &ldquo;Detailed Initialization Procedure&rdquo;</a></p>
</blockquote><h1 id="应用场景" class="headerLink">
    <a href="#%e5%ba%94%e7%94%a8%e5%9c%ba%e6%99%af" class="header-mark"></a>应用场景</h1><p>通过上面的分析，我们大致了解了 ART 虚拟机的文件、代码加载流程，以及对应 Java 方法和指令的运行过程。正所谓无利不起早，之所以花费这么多时间精力去学习 ART，是因为其在 Android 运行过程中起着举足轻重的作用，下面就列举一些常见的应用场景。</p>
<h2 id="热修复--hook" class="headerLink">
    <a href="#%e7%83%ad%e4%bf%ae%e5%a4%8d--hook" class="header-mark"></a>热修复 &amp; Hook</h2><p>所谓热修复，就是在不修改原有代码的基础上修改应用功能，比如替换某些类方法的实现，达到热更新的目的。犹记得在几年前，热修复的概念在 Android 生态中甚嚣尘上，随着 ART 替换 Dalvik，以及碎片化引入的一系列问题导致这种方案逐渐销声匿迹。但是热修复的使用场景并没有完全消失，比如在 Android 应用安全研究中 Hook 的概念也是热修复的一种延续。</p>
<p>那么根据前面总结的知识可以考虑一个问题，如何在运行时劫持某个 Java 方法的执行流程？最好是可以在指定方法调用前以及返回前分别触发我们自己定义的回调，从而实现调用参数和返回值的观察和修改。</p>
<p>根据前文对方法调用和代码加载的分析，Android 中的 Java 方法在 ART 中执行都会通过 <code>ArtMethod::Invoke</code> 进行调用，在其内部要么通过解释器直接解释执行(配合 JIT)；要么通过  <code>GetEntryPointFromQuickCompiledCode</code> 获取本地代码进行执行，当然后者在某些场景下依然会回退到解释器，但入口都是固定的，即
<code>entry_point_from_quick_compiled_code</code> 所指向的 quick 代码。因此，要想实现 Java 方法调用的劫持，可以有几种思路:</p>
<ol>
<li>修改 <code>ArtMethod::Invoke</code> 这个 C++ 函数为我们自己的实现，在其中增加劫持逻辑；</li>
<li>修改目标 Java 方法属性，令所有调用都走 quick 分支，然后将 <code>entry_point_from_quick_compiled_code</code> 修改为指向我们自己的实现，从而实现劫持；</li>
<li>类似于上述方法，不过不修改指针的值，而是修改 stub code；</li>
<li>……</li>
</ol>
<p>当然，前途是光明的，道路是曲折的，这些方法看起来都很直观，但实现起来有很多工程化的难点。比如需要仔细处理调用前后的堆栈令其保持平衡，这涉及到 inline-hook 框架本身的鲁棒性；有比如在新版本中对于系统类方法的调用，ART 会直接优化成汇编跳转而绕过 ArtMethod 方法的查找过程，因此方法 1、2 无法覆盖到这些场景，……不一而足。</p>
<p>以大家常用的 frida 为例，其对 Java 方法 Hook 的实现在 <code>frida-java-bridge</code>，关键代码在 <code>lib/android.js</code> 文件中:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-74" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">class</span> <span class="nx">ArtMethodMangler</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">replace</span> <span class="p">(</span><span class="nx">impl</span><span class="p">,</span> <span class="nx">isInstanceMethod</span><span class="p">,</span> <span class="nx">argTypes</span><span class="p">,</span> <span class="nx">vm</span><span class="p">,</span> <span class="nx">api</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="p">.</span><span class="nx">originalMethod</span> <span class="o">=</span> <span class="nx">fetchArtMethod</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="nx">methodId</span><span class="p">,</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">originalFlags</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">originalMethod</span><span class="p">.</span><span class="nx">accessFlags</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">((</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="nx">kAccXposedHookedMethod</span><span class="p">)</span> <span class="o">!==</span> <span class="mi">0</span> <span class="o">&amp;&amp;</span> <span class="nx">xposedIsSupported</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="c1">// 检测 Xposed，如果已经被 Xposed hook 了会从新获取源函数 ...
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="p">}</span>
</span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">replacementMethodId</span> <span class="o">=</span> <span class="nx">cloneArtMethod</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">replacementMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">jniCode</span><span class="o">:</span> <span class="nx">impl</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">accessFlags</span><span class="o">:</span> <span class="p">((</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="o">~</span><span class="p">(</span><span class="nx">kAccCriticalNative</span> <span class="o">|</span> <span class="nx">kAccFastNative</span> <span class="o">|</span> <span class="nx">kAccNterpEntryPointFastPathFlag</span><span class="p">))</span> <span class="o">|</span> <span class="nx">kAccNative</span><span class="p">)</span> <span class="o">&gt;&gt;&gt;</span> <span class="mi">0</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">quickCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artClassLinker</span><span class="p">.</span><span class="nx">quickGenericJniTrampoline</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="nx">interpreterCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artInterpreterToCompiledCodeBridge</span>
</span></span><span class="line"><span class="cl"><span class="p">},</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 修改 flags 使解释器执行到我们想要的分支
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kd">let</span> <span class="nx">hookedMethodRemovedFlags</span> <span class="o">=</span> <span class="nx">kAccFastInterpreterToInterpreterInvoke</span> <span class="o">|</span> <span class="nx">kAccSingleImplementation</span> <span class="o">|</span> <span class="nx">kAccNterpEntryPointFastPathFlag</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">((</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="nx">kAccNative</span><span class="p">)</span> <span class="o">===</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">hookedMethodRemovedFlags</span> <span class="o">|=</span> <span class="nx">kAccSkipAccessChecks</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">accessFlags</span><span class="o">:</span> <span class="p">(</span><span class="nx">originalFlags</span> <span class="o">&amp;</span> <span class="o">~</span><span class="p">(</span><span class="nx">hookedMethodRemovedFlags</span><span class="p">))</span> <span class="o">&gt;&gt;&gt;</span> <span class="mi">0</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 将 Nterp 解释器的入口替换为 art_quick_to_interpreter_bridge 从而令代码跳转到 quick 入口
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="kr">const</span> <span class="nx">quickCode</span> <span class="o">=</span> <span class="k">this</span><span class="p">.</span><span class="nx">originalMethod</span><span class="p">.</span><span class="nx">quickCode</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="p">{</span> <span class="nx">artNterpEntryPoint</span> <span class="p">}</span> <span class="o">=</span> <span class="nx">api</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="nx">artNterpEntryPoint</span> <span class="o">!==</span> <span class="kc">undefined</span> <span class="o">&amp;&amp;</span> <span class="nx">quickCode</span><span class="p">.</span><span class="nx">equals</span><span class="p">(</span><span class="nx">artNterpEntryPoint</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">patchArtMethod</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">quickCode</span><span class="o">:</span> <span class="nx">api</span><span class="p">.</span><span class="nx">artQuickToInterpreterBridge</span>
</span></span><span class="line"><span class="cl">      <span class="p">},</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 开启劫持
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">isArtQuickEntrypoint</span><span class="p">(</span><span class="nx">quickCode</span><span class="p">))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">interceptor</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">ArtQuickCodeInterceptor</span><span class="p">(</span><span class="nx">quickCode</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">        <span class="nx">interceptor</span><span class="p">.</span><span class="nx">activate</span><span class="p">(</span><span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="p">.</span><span class="nx">interceptor</span> <span class="o">=</span> <span class="nx">interceptor</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 使用 hash 表记录已经替换的方法，方便后续恢复
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>    <span class="nx">artController</span><span class="p">.</span><span class="nx">replacedMethods</span><span class="p">.</span><span class="nx">set</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="nx">replacementMethodId</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="nx">notifyArtMethodHooked</span><span class="p">(</span><span class="nx">hookedMethodId</span><span class="p">,</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>其中 Nterp 是 ART 中一个改良过的解释器，用于替代早期 Dalvik 的 mterp 解释器，这里先不展开实现的细节，只需关注实际执行劫持的地方，即 <code>interceptor.activate(vm)</code>。interceptor 在实例化时指定的 quickCode 即为对应 ArtMethod 的快速执行入口，activate 代码如下:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-75" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nx">activate</span> <span class="p">(</span><span class="nx">vm</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">_createTrampoline</span><span class="p">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="p">{</span> <span class="nx">trampoline</span><span class="p">,</span> <span class="nx">quickCode</span><span class="p">,</span> <span class="nx">redirectSize</span> <span class="p">}</span> <span class="o">=</span> <span class="k">this</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">writeTrampoline</span> <span class="o">=</span> <span class="nx">artQuickCodeReplacementTrampolineWriters</span><span class="p">[</span><span class="nx">Process</span><span class="p">.</span><span class="nx">arch</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">prologueLength</span> <span class="o">=</span> <span class="nx">writeTrampoline</span><span class="p">(</span><span class="nx">trampoline</span><span class="p">,</span> <span class="nx">quickCode</span><span class="p">,</span> <span class="nx">redirectSize</span><span class="p">,</span> <span class="nx">vm</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">overwrittenPrologueLength</span> <span class="o">=</span> <span class="nx">prologueLength</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="k">this</span><span class="p">.</span><span class="nx">overwrittenPrologue</span> <span class="o">=</span> <span class="nx">Memory</span><span class="p">.</span><span class="nx">dup</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="nx">quickCodeAddress</span><span class="p">,</span> <span class="nx">prologueLength</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">writePrologue</span> <span class="o">=</span> <span class="nx">artQuickCodePrologueWriters</span><span class="p">[</span><span class="nx">Process</span><span class="p">.</span><span class="nx">arch</span><span class="p">];</span>
</span></span><span class="line"><span class="cl">    <span class="nx">writePrologue</span><span class="p">(</span><span class="nx">quickCode</span><span class="p">,</span> <span class="nx">trampoline</span><span class="p">,</span> <span class="nx">redirectSize</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>可以看到 frida 实际上是使用了我们上述的第 3 种 Hook 思路，即修改 stub code 为我们的劫持代码，这种方式一般称之为 <strong>dynamic callee-side rewriting</strong>，优点是即便对于 OAT 极致优化的系统类方法也同样有效。当然，我们这里只是管中规豹，实际的实现上还有很多细节值得学习，感兴趣的可以自行阅读代码。</p>
<h2 id="安全加固" class="headerLink">
    <a href="#%e5%ae%89%e5%85%a8%e5%8a%a0%e5%9b%ba" class="header-mark"></a>安全加固</h2><p>了解过 Android 逆向工程的人应该都知道，基于 Java 编译出来的 Dalvik 字节码其实很好理解，加上一些开源或者商业的反编译工具，甚至可以将字节码还原为和源代码非常接近的 Java 代码表示。这对于很多想在代码中隐藏秘密的公司而言是很不愿意看到的。</p>
<p>因此，安全工程师们就想出了一些保护代码防止静态逆向分析的方案，业内常称为 <strong>加壳</strong>，国外叫做 <strong>Packer</strong>，即在原始字节码上套上一层保护壳，并在运行时进行执行解密还原。</p>
<p>回顾我们学习的知识可以脑暴出几种安全加固方案(其实是业内已有方案):</p>
<ol>
<li>把整个 DEX 文件加密，然后在壳程序启动时还原解密文件并加载；</li>
<li>优化上述方案，不落地文件，直接在内存中解密加载；</li>
<li>提取出 DEX 文件中的字节码，并在运行时还原；</li>
<li>替换掉 DEX 文件中每个方法的字节码为解密代码，运行时解密执行；</li>
<li>……</li>
</ol>
<p>这些加固方案根据解密粒度不同也常称为整体壳、抽取壳。对于整体加密的方案不必多说，在 PC 时代也有很多类似的混淆方法；而对于抽取壳，实现就百花齐放了，比如有的加固方案是在类初始化期间进行还原，有的是在方法执行前进行还原。</p>
<p>回顾上面介绍热修复的内容，壳代码其实也可以看做是一个热修复框架，只不过是对于每个函数都进行了劫持，在目标函数运行前对实际的字节码进行还原；</p>
<p>有些类级别的加固则是基于上文中代码加载流程，在类的初始化函数(<code>&lt;clinit&gt;</code>)中执行解密操作，因为 Java 标准保证了这是一个类最先执行的代码。</p>
<p>由于抽取壳本身对字节码进行了加密，因此在应用安装期间 dex2oat 就无法优化这些代码，以至于在运行时只能通过解释执行，虽然有一部分 JIT 的加持，但还是让 ART 的大部分优化心血付诸东流；另外，加壳本身会使用到 ART 中的一些内部符号和偏移，因此需要针对不同版本进行适配，一个不小心就是用户端的持续崩溃。</p>
<p>也因为这些原因，很多头部厂商的 Android 应用其实是不加壳的，对于真正需要保护的代码，可以选择 JNI 用 C/C++ 实现，并配上 LLVM 成熟的混淆方案进行加固。</p>
<h2 id="脱壳" class="headerLink">
    <a href="#%e8%84%b1%e5%a3%b3" class="header-mark"></a>脱壳</h2><p>由于很多安全公司把加固做成了商业服务，因此除了正常应用，大部分恶意软件和非法应用也都用上了商业的加固方案，这对于正义的安全研究员而言是一个确实的阻碍，因此脱壳也就成了常见需求。</p>
<p>一开始我们在遇到加固的应用时候会先尝试进行手动进行分析、调试、还原，但是后来大家发现其实基于 ART 的运行模式有更通用的解决方式。</p>
<p>这里以目前相对较新的抽取壳为例，回顾上文代码方法调用和代码加载的章节，不论加固的抽取和还原方法如何，最终还是要回到解释执行的(至少在 JIT 之前)，因为加密的代码在安装时并没有被 AOT 优化。而且为了保证原始代码逻辑不变，对应加密方法在实际运行之前肯定需要被正确解密还原。</p>
<p>基于这点事实，我们可以在 ArtMethod 调用前进行断点，然后通过 <code>method-&gt;GetDexFile()</code> 获得对应 dex 文件在内存中的地址并进行转储保存。如果当前内存中的 dex 部分偏移被恶意修改，那么还可以通过 <code>method-&gt;GetCodeItem()</code> 获取对应方法解密后的字节码地址进行手动转储恢复。</p>
<p>如果要恢复完整的 dex 文件，则需要令目标程序在运行时调用所有类的所有方法，这显然不太现实；不过网上已经有了一些开源的方案基于主动调用的思路去批量伪造方法调用，触发壳的解密逻辑从而实现全量还原，比如 <a href="https://github.com/zyq8709/DexHunter" target="_blank" rel="noopener noreferrer">DexHunter</a> 和 <a href="https://github.com/hanbinglengyue/FART" target="_blank" rel="noopener noreferrer">FART</a>，都是通过修改 Android 源码实现的脱壳方案。</p>
<p>正如上节所说，安全加固方案五花八门，很难有一种绝对通用的方法去还原所有加固，往往还需要针对不同的壳做一些微小的适配工作。但总的来说，脱壳一方比写壳一方还是占优势的，前者只需要针对一种环境实现，不用考虑性能成本；后者则需要对 ART 有更深的理解来保证加固程序的稳定性，同时还要针对不同环境都进行覆盖，这也是攻防不对等的一个典型案例吧。</p>
<h2 id="方法跟踪" class="headerLink">
    <a href="#%e6%96%b9%e6%b3%95%e8%b7%9f%e8%b8%aa" class="header-mark"></a>方法跟踪</h2><p>对于上述 Android 应用加壳的方案，在数次攻防角斗下已经被证明了只能作为辅助防护，因此移动安全厂商又提出了一些新的加固方案，比如直接对字节码本身下手，套用 LLVM 控制流和数据流混淆的那一套方案，将字节码的执行顺序打乱，插入各种无效指令来阻碍逆向工程；又或者将字节码的实现抽批量自动取到 JNI 层，并辅以二进制级别的安全加固，这种方案通常称为 Java2C，即将 Java 代码转译成 C 代码编译来防止逆向分析。……</p>
<p>这时，传统的脱壳方法就不见得有效了，因为即便还原出字节码或者 Java 代码，其流程也是混乱的，对于 Java2C 则更不用说，只能在二进制中想办法将 JNI 调用还原。</p>
<p>不过我们可以思考一下，逆向工程的目的是什么？如果是为了分析还原程序的执行流程，对其行为进行画像和取证，那么完全可以通过动态跟踪的方式实现。上文中已经介绍了如果对某个指定方法进行热修复或者说 hook，那么这里的思路就是对应用中的所有 Java 方法都进行 hook，从而实现我们的运行时方法跟踪行为。</p>
<p>例如针对每个 Java 方法在进入和退出前都插入我们的 hook 代码，作用就是发送函数进出事件及其相关信息，如进程、线程 ID、方法名、参数等，接收端处理数据后实现一个树状的调用流图。</p>
<p>一个简单的调用流图示例如下所示:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
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    ">      
    <button 
      class="
        code-block-button
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
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          group-[.is-open]:tw-block 
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          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
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          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-76" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>com.evilpan.Foo.onCreate
├── com.evilpan.Foo.getContacts
│   ├── Context.getContentResolver
│   ├── ContentResolver.query
│   ├── Cursor.getColumnIndex
│   ├── Cursor.getString
│   ├── ...
│   └── Cursor.close
└── com.evilpan.Foo.upload
    ├── URL.&lt;init&gt;
    ├── URL.openConnection
    ├── HttpURLConnection.getOutputStream
    ├── BufferWriter.write
    └── ...</code></pre></code></pre>
</div>
<p>前端通过处理和过滤这些数据，可以在很大程度上还原程序行为。那么要如何实现所有 Java 方法的追踪呢？<code>entry_point_from_quick_compiled_code_</code> 是一个重点关注的点，但如果我们想要像 frida 一样劫持，就需要对每个方法做许多额外的工作，比如修改函数的 access_flag，修改解释器执行流程等。因此关键点还是在于如何同时处理解释执行和快速执行的代码，并将潜在的 JIT 运行时优化考虑进去，自己造一个轮子无可厚非，但其实 ART 中已经提供了这么一个“后门”，那就是在上文 <code>LinkCode</code> 代码中的那句:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
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        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">cpp</p>
      </button>

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          tw-hidden 
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    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
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      <button 
        class="
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        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-77" 
    class="
      chroma 
      !tw-block 
      tw-p-0
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      "><span class="line"><span class="cl"><span class="n">runtime</span><span class="o">-&gt;</span><span class="n">GetInstrumentation</span><span class="p">()</span><span class="o">-&gt;</span><span class="n">InitializeMethodsCode</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">quick_code</span><span class="p">);</span></span></span></code></pre>
</div>
<p>在 <code>Instrumentation::InitializeMethodsCode</code> 的实现中，会先判断当前是否已经注册了追踪的 stub，如果有的话会直接替换对应方法的入口点:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
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          <p class="tw-select-none !tw-my-1">cpp</p>
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  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-78" 
    class="
      chroma 
      !tw-block 
      tw-p-0
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      tw-transition-[max-height] 
      tw-duration-500 
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      "><span class="line"><span class="cl"><span class="c1">// art/runtime/instrumentation.cc
</span></span></span><span class="line"><span class="cl"><span class="c1"></span><span class="kt">void</span> <span class="n">Instrumentation</span><span class="o">::</span><span class="n">InitializeMethodsCode</span><span class="p">(</span><span class="n">ArtMethod</span><span class="o">*</span> <span class="n">method</span><span class="p">,</span> <span class="k">const</span> <span class="kt">void</span><span class="o">*</span> <span class="n">aot_code</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">REQUIRES_SHARED</span><span class="p">(</span><span class="n">Locks</span><span class="o">::</span><span class="n">mutator_lock_</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// Use instrumentation entrypoints if instrumentation is installed.
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>  <span class="k">if</span> <span class="p">(</span><span class="n">UNLIKELY</span><span class="p">(</span><span class="n">EntryExitStubsInstalled</span><span class="p">()))</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n">method</span><span class="o">-&gt;</span><span class="n">IsNative</span><span class="p">()</span> <span class="o">&amp;&amp;</span> <span class="n">InterpretOnly</span><span class="p">())</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="n">UpdateEntryPoints</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">GetQuickToInterpreterBridge</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="n">UpdateEntryPoints</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">GetQuickInstrumentationEntryPoint</span><span class="p">());</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// ...
</span></span></span></code></pre>
</div>
<p>对于已经初始化过的 ArtMethod，还可以用 <code>Instrumentation::InstallStubsForMethod</code> 去为指定方法安装跟踪代码。关于 Instrumentation 网上还没有太多公开资料，需要通过源码去进一步研究。</p>
<p>当然还是那句老话，想法是简单的，实现是复杂的，这其中目前可预计到的问题就有:</p>
<ol>
<li>运行时开销；</li>
<li>开启和停止方式，可以通过中断去控制；</li>
<li>发送事件的方式，使用单独的线程进行队列发送，多进程通信方式；</li>
<li>动态跟踪的过滤，比如进入到系统方法中就不再进行跟踪；</li>
<li>循环调用的识别，接收端只能看到一系列循环事件；</li>
<li>……</li>
</ol>
<p>因此再展开就说来话长了，目前也只是在探索阶段，后续有机会再单独分享这部分内容吧。</p>
<h1 id="总结" class="headerLink">
    <a href="#%e6%80%bb%e7%bb%93" class="header-mark"></a>总结</h1><p>本文主要目的是分析 Android 12 中 ART 的实现，包括 Java 方法初始化和执行的过程。基于对 ART 的深入理解，我们也列举了几种实践中经常遇到的场景，比如热修复、动态注入、安全加固、脱壳等。也许在工作中信奉拿来主义，只需要工具能用就行，但了解工具背后的原理，才能更好适应当前不断激化的攻防对抗环境，从而更好地迎接未来的挑战。</p>
<h1 id="参考资料" class="headerLink">
    <a href="#%e5%8f%82%e8%80%83%e8%b5%84%e6%96%99" class="header-mark"></a>参考资料</h1><ul>
<li><a href="https://blog.csdn.net/Luoshengyang/article/details/8852432" target="_blank" rel="noopener noreferrer">罗升阳: Dalvik 系列</a></li>
<li><a href="https://blog.csdn.net/Luoshengyang/article/details/39256813" target="_blank" rel="noopener noreferrer">罗升阳: ART 系列</a></li>
<li><a href="https://www.virusbulletin.com/uploads/pdf/conference_slides/2014/Yu-VB2014.pdf" target="_blank" rel="noopener noreferrer">Android Packer - facing the challenges, building solutions(slides)</a></li>
<li><a href="https://res-www.zte.com.cn/mediares/magazine/publication/com_en/article/201803/RONGYu.pdf" target="_blank" rel="noopener noreferrer">DexDefender: A DEX Protection Scheme to Withstand MemoryDump Attack Based on Android Platform</a></li>
<li><a href="http://publications.cispa.saarland/143/" target="_blank" rel="noopener noreferrer">ArtHook: Callee-side Method Hook Injection on the New Android Runtime ART</a></li>
<li><a href="https://weishu.me/2017/11/23/dexposed-on-art/" target="_blank" rel="noopener noreferrer">我为 Dexposed +1s: 论ART上运行时 Method AOP 实现</a></li>
<li><a href="https://github.com/tiann/epic" target="_blank" rel="noopener noreferrer">epic - Dynamic java method AOP hook for Android</a></li>
<li><a href="https://github.com/frida/frida-java-bridge" target="_blank" rel="noopener noreferrer">frida-java-bridge</a></li>
</ul>]]></description>
</item><item>
    <title>免越狱调试与分析黑盒iOS应用</title>
    <link>https://evilpan.com/2019/04/07/ios-reverse-basics/</link>
    <pubDate>Sun, 07 Apr 2019 22:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2019/04/07/ios-reverse-basics/</guid>
    <description><![CDATA[<p><a href="https://evilpan.com/2019/04/06/ios-basics/" target="_blank" rel="noopener noreferrer">上篇文章</a>我们从开发者的角度介绍了如何建立iOS项目并且在真机上运行，
<a href="https://evilpan.com/2019/04/05/objc-basics/" target="_blank" rel="noopener noreferrer">上上篇文章</a>则介绍了Objective-C的基本概念和用法。而这一切，都是为了这次的铺垫。
今天，我们就要从攻击者的角度，尝试对黑盒iOS应用进行调试与动态跟踪(instrument)。</p>
<h1 id="前言" class="headerLink">
    <a href="#%e5%89%8d%e8%a8%80" class="header-mark"></a>前言</h1><p>为什么要执着于免越狱呢？因为随着iOS系统的不断更新，其安全性也越来越高，
挖掘越狱漏洞也越来越难，很多新版本都已经没有公开的越狱方案了。
近来苹果也会给提交越狱漏洞的白帽不菲的奖励， 加上越狱对于普通用户的好处也越来越少，
很多越狱工具的开发者也逐渐不再更新维护。因此，免越狱分析，很有可能是未来唯一的方法。</p>
<h1 id="how" class="headerLink">
    <a href="#how" class="header-mark"></a>How</h1><p>其实免越狱测试应用也不是什么新技术了，Android中也有类似免root测试的方法。
而这两个方法其实本质上都是一样的，那就是 —— <strong>重打包</strong>。</p>
<p>对于Android来说，就是将安装包解压后注入字节码，使得应用在启动前加载我们准备的<code>.so</code>动态库，
从而实现在应用的上下文执行任意代码的目的；对于iOS也是一样，区别是所注入的动态库为<code>.dylib</code>。</p>
<h1 id="获取目标" class="headerLink">
    <a href="#%e8%8e%b7%e5%8f%96%e7%9b%ae%e6%a0%87" class="header-mark"></a>获取目标</h1><p>在<a href="https://evilpan.com/2019/04/06/ios-basics/" target="_blank" rel="noopener noreferrer">上篇文章</a>中其实有说了，开发者在编译iOS或者MacOS项目时，最终生成的应该是<code>.app</code>文件，
但在iOS中还需要对app文件进行打包，生成<code>.ipa</code>文件。AppStore下载的应用实际上是加密ipa，
一般而言可以使用下面的工具来进行还原，这一步俗称砸壳。</p>
<ul>
<li><a href="https://github.com/KJCracks/Clutch" target="_blank" rel="noopener noreferrer">Clutch- Fast iOS executable dumper</a></li>
<li><a href="https://github.com/stefanesser/dumpdecrypted" target="_blank" rel="noopener noreferrer">dumpdecrypted - Dumps decrypted mach-o files from encrypted iPhone applications from memory to disk</a></li>
<li><a href="http://www.alonemonkey.com/2018/01/30/frida-ios-dump/" target="_blank" rel="noopener noreferrer">frida-ios-dump</a></li>
</ul>
<p>砸壳操作本质上是在运行时从内存里将原始文件导出，因此都需要有在源程序上下文中执行代码的能力，
也就是说，需要越狱。对于我们的场景而言，可以在第三方应用市场去下载已经解密的ipa文件，
比如<a href="https://www.iphonecake.com/" target="_blank" rel="noopener noreferrer">AppCake</a>或者PP助手（以及各种xx助手）等。</p>
<p>Tips：</p>
<pre><code>对于PP助手，可以用下面的地址搜索对应应用：
    https://www.25pp.com/ios/search_app_0/关键词
在应用详情界面中，通过查看网页源代码即可看到base64编码的ipa的下载地址。
</code></pre>
<h2 id="文件分析" class="headerLink">
    <a href="#%e6%96%87%e4%bb%b6%e5%88%86%e6%9e%90" class="header-mark"></a>文件分析</h2><p>以2048小游戏为例，我们把下载的越狱程序保存为<code>pp2048.ipa</code>，前面也说过，ipa本质上是zip格式，
将其解压后目录结构如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-24" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ unzip pp2048.ipa -d pp2048
$ tree -d 1 pp2048
1 [error opening dir]
pp2048
├── META-INF
└── Payload
    └── 2048.app
        ├── 2048
        ├── Frameworks
        ├── _CodeSignature
        ├── en.lproj
        ├── es.lproj
        ├── fr.lproj
        ├── ...
        └── zh-Hans.lproj</code></pre></code></pre>
</div>
<h2 id="检查是否加密" class="headerLink">
    <a href="#%e6%a3%80%e6%9f%a5%e6%98%af%e5%90%a6%e5%8a%a0%e5%af%86" class="header-mark"></a>检查是否加密</h2><p><code>otool</code>命令可以输出app的load commands，可通过查看cryptid标志位来判断app加密状态。
其中1代表加密，0代表已解密：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-25" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ otool -l pp2048/Payload/2048.app/2048  <span class="p">|</span> egrep <span class="s1">&#39;LC_ENCRYPTION_INFO|cryptid&#39;</span>
</span></span><span class="line"><span class="cl">          cmd LC_ENCRYPTION_INFO
</span></span><span class="line"><span class="cl">      cryptid <span class="m">0</span>
</span></span><span class="line"><span class="cl">          cmd LC_ENCRYPTION_INFO_64
</span></span><span class="line"><span class="cl">      cryptid <span class="m">0</span></span></span></code></pre>
</div>
<p>这一步对于我们后续的分析是必须的，因为如果app没有解密，那么后面即使重打包安装了，
也依然无法运行。</p>
<h1 id="签名与重打包" class="headerLink">
    <a href="#%e7%ad%be%e5%90%8d%e4%b8%8e%e9%87%8d%e6%89%93%e5%8c%85" class="header-mark"></a>签名与重打包</h1><p>有了解密的应用程序，接下来要做的就是对其进行重打包从而注入我们的代码了。
在重打包之前，可以先查看一下原APP的签名信息。</p>
<h2 id="查看app签名" class="headerLink">
    <a href="#%e6%9f%a5%e7%9c%8bapp%e7%ad%be%e5%90%8d" class="header-mark"></a>查看app签名</h2><p>解压后可以看到Payloads下有<code>2048.app</code>文件夹，这便是我们需要的应用程序。
可以用苹果自带的<code>codesign</code>工具验证和查看签名信息：</p>
<p>验证签名：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-26" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ codesign --verify pp2048/Payload/2048.app
pp2048/Payload/2048.app: invalid signature (code or signature have been modified)
In architecture: armv7</code></pre></code></pre>
</div>
<p>可以看到签名验证失败，一般越狱应用都会去除掉签名信息，如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-27" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ codesign -d -vv pp2048/Payload/2048.app
Executable=/reverse/iOS/pp2048/Payload/2048.app/2048
Identifier=com.ketchapp.2048
Format=app bundle with Mach-O universal (armv7 arm64)
CodeDirectory v=20200 size=68369 flags=0x0(none) hashes=2129+5 location=embedded
Signature size=4297
Authority=(unavailable)
Info.plist=not bound
TeamIdentifier=BB5K34ZCVK
Sealed Resources version=2 rules=11 files=95
Internal requirements count=1 size=100</code></pre></code></pre>
</div>
<p>这一步不是必须的，但是有助于我们了解目标应用程序。</p>
<h2 id="简单重打包" class="headerLink">
    <a href="#%e7%ae%80%e5%8d%95%e9%87%8d%e6%89%93%e5%8c%85" class="header-mark"></a>简单重打包</h2><p>在注入代码之前，我们可以先尝试修改应用内的资源文件来重新打包看是否能正常运行。
步步为营，这样排除由于注入代码而导致的错误。</p>
<p>要做的很简单，向app中添加一个文本文件：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-28" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nb">echo</span> <span class="s2">&#34;Leave Me&#34;</span> &gt; pp2048/Payload/2048.app/evilpan.txt</span></span></code></pre>
</div>
<p>然后重新打包：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-29" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="nb">cd</span> pp2048 <span class="o">&amp;&amp;</span> zip -qry ../pp2048-repack.ipa Payload</span></span></code></pre>
</div>
<p>这样就生成了新的<code>pp2048-repack.ipa</code>文件。这时候的ipa还不能用，需要对其进行签名。</p>
<h2 id="ipa签名" class="headerLink">
    <a href="#ipa%e7%ad%be%e5%90%8d" class="header-mark"></a>ipa签名</h2><p>苹果要求ipa需要经过签名才能部署，Xcode7后可以使用个人Apple ID来进行provision签名，
用于在自己的设备上对应用进行测试。值得一提的是，ipa的签名和app签名还不太一样，
后者是用codesign工具进行签名，而ipa则需要第三方工具的帮助。</p>
<p>可以用于给ipa（重）签名的工具有一大把，比如：</p>
<ul>
<li><a href="https://github.com/DanTheMan827/ios-app-signer" target="_blank" rel="noopener noreferrer">ios-app-signer</a>(图形界面)</li>
<li><a href="https://github.com/maciekish/iReSign" target="_blank" rel="noopener noreferrer">iReSign</a>(图形界面)</li>
<li><a href="https://github.com/saucelabs/isign" target="_blank" rel="noopener noreferrer">isign</a>(python)</li>
<li><a href="https://github.com/nowsecure/node-applesign" target="_blank" rel="noopener noreferrer">node-applesign</a>(nodejs)</li>
</ul>
<p>还有很多没列举到的，这里使用<code>node-appsign</code>来签名：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-30" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">applesign -i <span class="nv">$SIGNID</span> -m /path/to/embedded.mobileprovision pp2048-repack.ipa -o pp2048-resign.ipa</span></span></code></pre>
</div>
<p>其中SIGNID指定用于签名的私钥，可用security命令来查看当前可用于给代码签名的SIGNID：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-31" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ security find-identity -v -p codesigning
  1) CDC7************************************ &#34;iPhone Developer: evilpan (V2KHK9DD9)&#34;
  2) A3BB************************************ &#34;org.radare.radare2&#34;
     2 valid identities found</code></pre></code></pre>
</div>
<blockquote>
  <p>实际测试中发现似乎只能用第一个也就是Apple ID生成的私钥来进行签名。</p>
</blockquote><p>在签名的命令中，还有一个需要提供的文件就是<code>embedded.mobileprovision</code>，
即<code>provision profiles</code>，这个文件可以在我们自己的iOS项目生成文件中找到，比如：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-32" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>/Users/Peter/Library/Developer/Xcode/DerivedData/HelloWorld-dnyjqrgxcjjobvfzytzhtzpmjlmx/Build/Products/Debug-iphoneos/HelloWorld.app/embedded.mobileprovision
# 或者
~/Library/MobileDevice/Provisioning Profiles/</code></pre></code></pre>
</div>
<p><code>provision profiles</code>是将签名，授权和沙盒联系起来文件，每个iOS开发者应该都不会陌生。
关于iOS/OSX代码签名和授权机制的介绍，强烈推荐<a href="https://objccn.io/issue-17-2/" target="_blank" rel="noopener noreferrer">这篇文章</a>，这里就不展开了。</p>
<p>签名完成后的ipa就可以部署到真机上了，比如用我们上一篇文章说到的<code>ios-deploy</code>：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-33" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">ios-deploy -b pp2048-resign.ipa</span></span></code></pre>
</div>
<p>安装成功！如果是第一次启动，会提示<code>不受信任的开发者</code>，安装提示允许即可正常运行。</p>
<h1 id="注入代码灵魂" class="headerLink">
    <a href="#%e6%b3%a8%e5%85%a5%e4%bb%a3%e7%a0%81%e7%81%b5%e9%ad%82" class="header-mark"></a>注入<del>代码</del>灵魂</h1><p>现在我们已经验证了重打包应用的可行性，接下来就要开始做点有用的事情了。
为了在应用中执行我们自己的代码，我们可以直接修改二进制的<code>2048.app/2048</code>文件，
毕竟，它只是一个运行于ARM平台的普通Mach-O文件而已：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-34" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ file pp2048/Payload/2048.app/2048
</span></span><span class="line"><span class="cl">pp2048/Payload/2048.app/2048: Mach-O universal binary with <span class="m">2</span> architectures: <span class="o">[</span>arm_v7:Mach-O executable arm_v7<span class="o">]</span> <span class="o">[</span>arm64<span class="o">]</span>
</span></span><span class="line"><span class="cl">pp2048/Payload/2048.app/2048 <span class="o">(</span><span class="k">for</span> architecture armv7<span class="o">)</span>:	Mach-O executable arm_v7
</span></span><span class="line"><span class="cl">pp2048/Payload/2048.app/2048 <span class="o">(</span><span class="k">for</span> architecture arm64<span class="o">)</span>:	Mach-O 64-bit executable arm64</span></span></code></pre>
</div>
<p>可以使用十六进制编辑器如<code>radare2</code>对其进行patch，不过这种方式太原始，做点简单修改还行，
不方便做太复杂的操作。所以，一般还是直接在Mach-O中注入少量指令，并使其在运行时加载我们的动态库，
这样就可以在动态库中实现复杂的操作了。</p>
<h2 id="动态注入dylib" class="headerLink">
    <a href="#%e5%8a%a8%e6%80%81%e6%b3%a8%e5%85%a5dylib" class="header-mark"></a>动态注入dylib</h2><p>在给iOS注入动态库之前，我们先在Mac下面测试一下注入动态库的可行性，二者平台是比较类似的。
首先编译一个简单的Mach-O可执行文件，如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-35" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ cat hello.m
</span></span><span class="line"><span class="cl"><span class="c1">#import &lt;Foundation/Foundation.h&gt;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">int main <span class="o">(</span>int argc, const char * argv<span class="o">[])</span>
</span></span><span class="line"><span class="cl"><span class="o">{</span>
</span></span><span class="line"><span class="cl">    @autoreleasepool <span class="o">{</span>
</span></span><span class="line"><span class="cl">        NSLog <span class="o">(</span>@<span class="s2">&#34;Hello, World!&#34;</span><span class="o">)</span><span class="p">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> 0<span class="p">;</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">$ clang -framework Foundation hello.m -o hello
</span></span><span class="line"><span class="cl">$ ./hello
</span></span><span class="line"><span class="cl">2019-04-07 12:38:10.031 hello<span class="o">[</span>17348:3859846<span class="o">]</span> Hello, World!</span></span></code></pre>
</div>
<p>然后准备一个动态库文件<code>libtest.m</code>：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">c</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-36" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="cp">#import &lt;Foundation/Foundation.h&gt;
</span></span></span><span class="line"><span class="cl"><span class="cp"></span>
</span></span><span class="line"><span class="cl"><span class="nf">__attribute__</span><span class="p">((</span><span class="n">constructor</span><span class="p">))</span> <span class="kt">void</span> <span class="nf">dylibMain</span><span class="p">()</span>
</span></span><span class="line"><span class="cl"><span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="err">@</span><span class="n">autoreleasepool</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nf">NSLog</span><span class="p">(</span><span class="err">@</span><span class="s">&#34;libtest LOADED!!!!!!!&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p><code>__attribute__((constructor))</code>宏描述dylibMain为动态库的constructor，即入口。
编译动态库的方法为：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-37" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ clang -framework Foundation libtest.m -shared -o libtest.dylib
</span></span><span class="line"><span class="cl">$ file libtest.dylib
</span></span><span class="line"><span class="cl">libtest.dylib: Mach-O 64-bit dynamically linked shared library x86_64</span></span></code></pre>
</div>
<p>在Linux中注入动态库最简单的方法就是使用<code>LD_LIBRARY</code>环境变量，
Mac下也有类似的环境变量，为<code>DYLD_INSERT_LIBRARIES</code>，如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-38" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ <span class="nv">DYLD_INSERT_LIBRARIES</span><span class="o">=</span>libtest.dylib ./hello
</span></span><span class="line"><span class="cl">2019-04-07 12:44:08.810 hello<span class="o">[</span>17497:3861923<span class="o">]</span> libtest LOADED!!!!!!!
</span></span><span class="line"><span class="cl">2019-04-07 12:44:08.812 hello<span class="o">[</span>17497:3861923<span class="o">]</span> Hello, World!</span></span></code></pre>
</div>
<p>可以看到动态库中的代码已经被调用了，而且是在main函数之前。</p>
<h2 id="二进制patch" class="headerLink">
    <a href="#%e4%ba%8c%e8%bf%9b%e5%88%b6patch" class="header-mark"></a>二进制patch</h2><p>在没越狱的iOS中，我们无法轻易给目标进程添加环境变量。不过既然能修改文件，
我们也可以将其改成在启动是自己加载指定动态库。有很多自动化工具可以帮助我们完成这个操作：</p>
<ul>
<li><a href="https://github.com/Tyilo/insert_dylib" target="_blank" rel="noopener noreferrer"><code>insert_dylib</code></a></li>
<li><a href="https://github.com/KJCracks/yololib" target="_blank" rel="noopener noreferrer">yololib</a></li>
</ul>
<p>这些工具的作用都是在Mach-O的<code>Load Commands</code>段中添加一条<code>LC_LOAD_DYLIB</code>。
关于Mach-O的详细文件格式可以参考<a href="https://lowlevelbits.org/parsing-mach-o-files/" target="_blank" rel="noopener noreferrer">PARSING MACH-O FILES</a>。</p>
<p>以<code>insert_dylib</code>为例，注入dylib只需一条命令：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-39" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ ./hello
2019-04-07 12:57:42.274 hello[17728:3865999] Hello, World!

$ insert_dylib libtest.dylib hello
Added LC_LOAD_DYLIB to hello_patched

$ ./hello_patched
2019-04-07 12:57:58.425 hello_patched[17752:3866077] libtest LOADED!!!!!!!
2019-04-07 12:57:58.425 hello_patched[17752:3866077] Hello, World!</code></pre></code></pre>
</div>
<h2 id="交叉编译" class="headerLink">
    <a href="#%e4%ba%a4%e5%8f%89%e7%bc%96%e8%af%91" class="header-mark"></a>交叉编译</h2><p>现在我们已经（在Mac上）验证了向二进制文件中注入动态库的可行性，接下来就是iOS了。
和Mac不同的是，iOS应用一般是ARM/ARM64版本，因此在x86的笔记本上，就需要交叉编译。
通过clang和Xcode提供的SDK，我们可以很方便在Mac上交叉编译iOS的应用或动态库：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
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    ">      
    <button 
      class="
        code-block-button
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        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
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          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-40" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">clang -framework Foundation libtest.m -shared -o libtest.dylib -arch armv7 -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS12.1.sdk -mios-simulator-version-min<span class="o">=</span><span class="m">6</span></span></span></code></pre>
</div>
<p>和ELF不同的是，Mach-O支持多架构，也就是说我们可以指定多个arch，生成的文件如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
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        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
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          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-41" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ file libtest.dylib
libtest.dylib: Mach-O universal binary with 2 architectures: [arm_v7:Mach-O dynamically linked shared library arm_v7] [arm64:Mach-O 64-bit dynamically linked shared library arm64]
libtest.dylib (for architecture armv7):	Mach-O dynamically linked shared library arm_v7
libtest.dylib (for architecture arm64):	Mach-O 64-bit dynamically linked shared library arm64</code></pre></code></pre>
</div>
<p>但是一般只需要支持armv7即可，因为iOS新的CPU会兼容老的架构，详见<a href="http://iossupportmatrix.com/" target="_blank" rel="noopener noreferrer">iOS Support Matrix</a>。</p>
<h2 id="签名" class="headerLink">
    <a href="#%e7%ad%be%e5%90%8d" class="header-mark"></a>签名</h2><p>新生成的<code>libtest.dylib</code>此时还不能直接添加到ipa中，要时刻记住在iOS中，
所有的<strong>代码</strong>都需要有合法的签名。</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
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    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-42" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ codesign -f -v -s $SIGNID libtest.dylib
libtest.dylib: signed Mach-O universal (armv7 arm64) [libtest]</code></pre></code></pre>
</div>
<h2 id="重打包" class="headerLink">
    <a href="#%e9%87%8d%e6%89%93%e5%8c%85" class="header-mark"></a>重打包</h2><p>将libtest.dylib拷贝到ipa，并注入到可执行文件中，参考上面简单重打包的方法，
对最后的ipa进行重新打包签名。这里为了看到标准输出，直接使用lldb调试启动：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-43" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>$ unzip pp2048-resign.ipa -d pp2048-resign
$ ios-deploy -b pp2048-resign/Payload/2048.app --debug -W
(lldb)     connect
(lldb)     run
success
libtest LOADED!!!!!!!
2019-04-07 13:49:49.731657+0800 2048[14630:3523860] [Accessibility] ****************** Loading GAX Client Bundle ****************
2019-04-07 13:49:50.085734+0800 2048[14630:3523860] [aurioc] 1029: failed: &#39;!pla&#39; (enable 2, outf&lt; 2 ch,  44100 Hz, Float32, non-inter&gt; inf&lt; 2 ch,      0 Hz, Float32, non-inter&gt;)
2019-04-07 13:49:50.127830+0800 2048[14630:3523860] error loading sound: a004
Process 14630 exited with status = 1 (0x00000001)
(lldb)</code></pre></code></pre>
</div>
<p>可以看到，libtest已经成功加载并执行了！这里需要一提的是我把libtest.m中的NSLog改成了printf，
因为测试中发现前者在运行时根本没有打印，这问题也令我测试了好久。</p>
<h1 id="动态调试" class="headerLink">
    <a href="#%e5%8a%a8%e6%80%81%e8%b0%83%e8%af%95" class="header-mark"></a>动态调试</h1><p>终于，我们成功在目标iOS应用中注入了我们自己的动态库！由于动态库的代码是我们自己写的，
因此可以编写复杂的插件，在应用上下文执行任意代码。</p>
<h2 id="lldb" class="headerLink">
    <a href="#lldb" class="header-mark"></a>lldb</h2><p>刚刚启动时我们使用了<code>ios-deploy</code>的<code>--debug</code>参数来启动lldbserver/client
并自动attach，lldb是LLVM中功能强大的调试器，功能与gdb类似，如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
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          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-44" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>(lldb) process interrupt
Process 14675 stopped
* thread #1, queue = &#39;com.apple.main-thread&#39;, stop reason = signal SIGSTOP
    frame #0: 0x00000002230efea4 libsystem_kernel.dylib`mach_msg_trap + 8
libsystem_kernel.dylib`mach_msg_trap:
-&gt;  0x2230efea4 &lt;+8&gt;: ret

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x2230efea8 &lt;+0&gt;: mov    x16, #-0x20
    0x2230efeac &lt;+4&gt;: svc    #0x80
    0x2230efeb0 &lt;+8&gt;: ret
Target 0: (2048) stopped.
(lldb) bt
* thread #1, queue = &#39;com.apple.main-thread&#39;, stop reason = signal SIGSTOP
  * frame #0: 0x00000002230efea4 libsystem_kernel.dylib`mach_msg_trap + 8
    frame #1: 0x00000002230ef37c libsystem_kernel.dylib`mach_msg + 72
    frame #2: 0x00000002234f5ad8 CoreFoundation`__CFRunLoopServiceMachPort + 236
    frame #3: 0x00000002234f0974 CoreFoundation`__CFRunLoopRun + 1396
    frame #4: 0x00000002234f00e0 CoreFoundation`CFRunLoopRunSpecific + 436
    frame #5: 0x0000000225769584 GraphicsServices`GSEventRunModal + 100
    frame #6: 0x0000000250740c00 UIKitCore`UIApplicationMain + 212
    frame #7: 0x000000010298ca20 2048`___lldb_unnamed_symbol49$$2048 + 88
    frame #8: 0x0000000222faebb4 libdyld.dylib`start + 4
(lldb)</code></pre></code></pre>
</div>
<p>例如，使用lldb来对抗ptrace反调试：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-45" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code># 设置断点
b ptrace

# 继续执行
continue

# 触发断点后直接跳转到返回地址
register write pc `$lr`

# 绕开ptrace继续运行
continue</code></pre></code></pre>
</div>
<p>lldb还支持python扩展，从而实现更丰富的自定义功能，详见<a href="https://lldb.llvm.org/python-reference.html" target="_blank" rel="noopener noreferrer">LLDB-Python</a>。</p>
<h2 id="frida" class="headerLink">
    <a href="#frida" class="header-mark"></a>frida</h2><p>除了使用调试器，我们还可以使用frida来进行动态的hook， 其<code>ObjC</code>
接口提供了许多针对ObjectiveC的封装，对于Objective-C项目，
可以使用frida很轻松地修改应用程序逻辑。</p>
<p>在非越狱场景使用frida主要是通过<code>frida-gadget</code>，即通过重打包注入
<code>frida-gadget.dylib</code>动态库，流程和注入我们自己编译的libtest.dylib一模一样。
关于frida的详细使用方法可以多看看其<a href="https://www.frida.re/docs/javascript-api/" target="_blank" rel="noopener noreferrer">官方文档</a>。</p>
<p>使用<code>insert_dylib</code>注入frida-gadget.dylib例子如下：</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-46" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">cp frida-gadget.dylib pp2048/Payload/2048.app/
</span></span><span class="line"><span class="cl">insert_dylib --strip-codesig --inplace <span class="s1">&#39;@executable_path/frida-gadget.dylib&#39;</span> pp2048/Payload/2048.app/2048</span></span></code></pre>
</div>
<h1 id="小结" class="headerLink">
    <a href="#%e5%b0%8f%e7%bb%93" class="header-mark"></a>小结</h1><p>至此，免越狱对应用进行动态分析的部分已经介绍完毕，这对于真正分析一个iOS程序还不完整，
但却是最重要的部分。分析一个iOS应用和其他应用一样，无非就是逆向分析与动态调试，
对于静态分析来说，一般也是使用<a href="https://revealapp.com/" target="_blank" rel="noopener noreferrer">Reveal</a>定位关键点，
然后把Mach-O拖进逆向分析工具如IDA/radare2/Ghidra进行分析，复杂点的需要面对混淆和对抗，
因此动态分析也能帮助理解静态代码。而动态分析除了用于分析还能用于持久化，
这对于日常工作生活而言，或许是更为实用的。</p>
<h1 id="参考链接" class="headerLink">
    <a href="#%e5%8f%82%e8%80%83%e9%93%be%e6%8e%a5" class="header-mark"></a>参考链接</h1><ul>
<li><a href="https://github.com/KJCracks/Clutch" target="_blank" rel="noopener noreferrer">Clutch- Fast iOS executable dumper</a></li>
<li><a href="https://github.com/stefanesser/dumpdecrypted" target="_blank" rel="noopener noreferrer">dumpdecrypted - Dumps decrypted mach-o files from encrypted iPhone applications from memory to disk</a></li>
<li><a href="http://www.alonemonkey.com/2018/01/30/frida-ios-dump/" target="_blank" rel="noopener noreferrer">frida-ios-dump</a></li>
<li><a href="https://github.com/Tyilo/insert_dylib" target="_blank" rel="noopener noreferrer">insert_dylib</a></li>
<li><a href="https://github.com/KJCracks/yololib" target="_blank" rel="noopener noreferrer">yololib</a></li>
<li><a href="https://objccn.io/issue-17-2/" target="_blank" rel="noopener noreferrer">代码签名探析</a></li>
<li><a href="https://github.com/Urinx/iOSAppHook" target="_blank" rel="noopener noreferrer">iOSAppHook</a></li>
<li><a href="https://www.frida.re/docs/javascript-api/" target="_blank" rel="noopener noreferrer">frida</a></li>
<li><a href="https://lldb.llvm.org/python-reference.html" target="_blank" rel="noopener noreferrer">LlDB Python</a></li>
</ul>]]></description>
</item><item>
    <title>一个色播APP逆向——初窥千万灰色直播产业</title>
    <link>https://evilpan.com/2019/01/05/reverse-live-porn-app/</link>
    <pubDate>Sat, 05 Jan 2019 22:40:00 &#43;0800</pubDate><author>
        <name>evilpan</name>
    </author><guid>https://evilpan.com/2019/01/05/reverse-live-porn-app/</guid>
    <description><![CDATA[<p>当你凝视深渊的时候, 深渊也在凝视你 —— 尼采.</p>
<p>从大约13年开始, 各大直播平台就如雨后春笋般冒出来, 犹记得当初还经常在午休时看DOTA的直播下饭. 后来不知道什么时候开始不再只是游戏直播, 而是一度刮起了女主播打擦边球的歪风邪气, 再后来严厉整顿, 各个平台也才逐渐收敛野蛮的发展, 逐渐步入正轨. 然而, 在阳光照不到的地方, 依然暗流涌动&hellip;</p>
<h1 id="前言" class="headerLink">
    <a href="#%e5%89%8d%e8%a8%80" class="header-mark"></a>前言</h1><p>发现这一迹象的契机, 是在总部位于卢森堡的某联盟网站发现开始有大量中国人拍摄的视频, 这在国际网站中是比较少见的. 而这些视频有个共同特征, 都打有某某直播的水印. 当时并没有在意, 加上年底也比较忙没空深究. 直到今天闲下来, 才想起来一探究竟.</p>
<p>首先按照水印的logo去搜索, 发现一个网站:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/8.png'   alt="webpage"  ></p>
<p>主页倒是中规中矩, 一副文艺社交的样子, 但是看标题就知道不一般啊. SM是什么东西, 熟悉二次元的朋友应该都不会陌生. 尽管我也有所了解, 但随着深入探究还是被震惊到, 所以建议未成年的小兄弟三思而百度.</p>
<p>说到百度, 来看看百度对这个站的收录是如何的:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/4.png'   alt="baidu"  ></p>
<p>竟然没有收录! 果然藏得很深. 什么叫暗网? 不是洋葱才叫暗网, 这也是一种暗网. 回过头来, 这个网站显然只是一个下载站, 也没有web访问界面, 因此我们要深入的话需要下载其手机APP. 网站提供了安卓和iOS版本, 我们先选择前者来进行分析.</p>
<p>分析APP的第一步当然是使用了. 以防万一, 这种APP还是先放在沙盒里运行, 保不准有什么顽固木马. 意料之中的是不支持x86的模拟器, 换到arm环境中正常启动. 贵圈的画风是怎么样的的? 截了一张图大家感受下:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/0.png'   alt="shot"  ></p>
<p>里面大致分为直播和回放, 当然天下没有免费的午餐, 每个视频或者直播都只能免费播放8秒, 8秒之后自动弹出购买窗口, 平均购买价格为288-988金币不等, 金币价格如下, 支持微信支付哦:)</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/7.png'   alt="price"  ></p>
<h1 id="探索" class="headerLink">
    <a href="#%e6%8e%a2%e7%b4%a2" class="header-mark"></a>探索</h1><p>大致玩了一遍这个APP, 基本功能都了解了, 接下来就从技术角度去探索下里面的实现. 一般来说逆向都要事先定下目标目标, 但是我们这次没有很明确的目标, 只是随便逛逛, 顺便复习下逆向技能.</p>
<h2 id="脱壳" class="headerLink">
    <a href="#%e8%84%b1%e5%a3%b3" class="header-mark"></a>脱壳</h2><p>首先在刚才的首页下载安卓apk, 用JADX看看大致的结构:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/3.png'   alt="shell"  ></p>
<p>看样子是使用了360的安全加固, 正好之前写了个脱壳脚本, 一键脱掉:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/2.png'   alt="unpack"  ></p>
<p>之后每个dex就可以正常使用jadx-gui来打开看了, 不过这里分享一个我比较喜欢的操作, 即用jadx命令行分别反编译各个dex, 然后用rsync合并到一处.</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-13" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">mkdir t380.jadx
</span></span><span class="line"><span class="cl"><span class="k">for</span> i in <span class="o">{</span>1..4<span class="o">}</span><span class="p">;</span><span class="k">do</span>
</span></span><span class="line"><span class="cl">    <span class="nv">JAVA_OPTS</span><span class="o">=</span><span class="s2">&#34;-Xmx8G&#34;</span> jadx -j <span class="m">1</span> -r -d t380_<span class="si">${</span><span class="nv">i</span><span class="si">}</span>.jadx unpacked_classes<span class="si">${</span><span class="nv">i</span><span class="si">}</span>.dex
</span></span><span class="line"><span class="cl">    rsync -a t380_<span class="si">${</span><span class="nv">i</span><span class="si">}</span>.jadx t380.jadx
</span></span><span class="line"><span class="cl"><span class="k">done</span></span></span></code></pre>
</div>
<p>为什么要这么做? 因为使用jadx-gui分别打开每个dex时候不论是查找函数还是查找引用都不太方便,
合并到一处可以直接用find/grep来查找. 这对于上百兆的巨型APK逆向还是很实用的.</p>
<h2 id="逆向" class="headerLink">
    <a href="#%e9%80%86%e5%90%91" class="header-mark"></a>逆向</h2><p>虽然这个APK只有50多M, 但代码量也不小, 直接看有点无从下手, 就从收费的地方开始吧! 毕竟这是整个环境最核心的部分. 我们打开一个直播间, 等8秒后弹出付费窗口, 定位这个地方:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/5.png'   alt="ui"  ></p>
<p>当然, 还有个比较直接的方法, 直接使用adb来查看当前置顶的activity:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-14" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">$ adb shell dumpsys window windows <span class="p">|</span> grep Focus
</span></span><span class="line"><span class="cl">  <span class="nv">mCurrentFocus</span><span class="o">=</span>Window<span class="o">{</span>be2e8cd u0 com.zhuoyigou.dese/com.zhuoyigou.dese.ui.live.activity.PlayerLiveActivtiy<span class="o">}</span>
</span></span><span class="line"><span class="cl">  <span class="nv">mFocusedApp</span><span class="o">=</span>AppWindowToken<span class="o">{</span>73e5eb8 <span class="nv">token</span><span class="o">=</span>Token<span class="o">{</span>bfded1b ActivityRecord<span class="o">{</span>2d0fb2a u0 com.zhuoyigou.dese/.ui.live.activity.PlayerLiveActivtiy t50<span class="o">}}}</span></span></span></code></pre>
</div>
<p>这个直播软件有个独特的地方是里面除了直播, 还有大部分是视频回放, 观看视频回放同样是需要收费. 定位方法也是同样, 回放的activity为<code>com.zhuoyigou.dese.ui.live.activity.PlayBackActivity</code>.</p>
<p>这里再分享个小技巧, 逆向过程中经常会需要用编辑器打开某个文件, 定义个shell函数可以加速该流程:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-15" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="k">function</span> jopen<span class="o">()</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">    <span class="nv">p</span><span class="o">=</span><span class="sb">`</span><span class="nb">echo</span> -n <span class="nv">$1</span> <span class="p">|</span> tr . /<span class="sb">`</span>
</span></span><span class="line"><span class="cl">    <span class="nv">file</span><span class="o">=</span><span class="nv">$p</span>.java
</span></span><span class="line"><span class="cl">    gvim -R <span class="nv">$file</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span></span></span></code></pre>
</div>
<p>这里以<code>PlayBackActivity</code>为例, 在jadx代码目录下, 可以直接这样打开文件:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-16" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">jopen com.zhuoyigou.dese.ui.live.activity.PlayBackActivity</span></span></code></pre>
</div>
<p>哈, 扯远了, 来看看弹窗付费的地方是如何实现的吧, 该类的部分代码风格如下:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/1.png'   alt="code"  ></p>
<p>做了一点对抗, 但是却没有完全混淆, 看来是不太了解木桶原理啊. 根据里面的方法名称, 发现一个比较有趣的函数:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-17" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">private</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">showTimeOutDialog</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">isMainActivityTop</span><span class="p">(</span><span class="n">GiftActivity</span><span class="p">.</span><span class="na">class</span><span class="p">))</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">reflashGiftActivity</span><span class="p">(</span><span class="s">&#34;1&#34;</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="o">!</span><span class="n">isFinishing</span><span class="p">())</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">LiveTimeOutDialog</span><span class="p">(</span><span class="k">this</span><span class="p">,</span><span class="w"> </span><span class="n">2131493319</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">show</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">setGold</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">mPlayBackBean</span><span class="p">.</span><span class="na">getLiveRoom</span><span class="p">().</span><span class="na">getPayMoney</span><span class="p">());</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">setTitle</span><span class="p">(</span><span class="s">&#34;replay&#34;</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">setCancelable</span><span class="p">(</span><span class="kc">false</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">setBuyOnClick</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">12</span><span class="p">(</span><span class="k">this</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mLiveTimeOutDialog</span><span class="p">.</span><span class="na">setNoBuyOnClick</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">13</span><span class="p">(</span><span class="k">this</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>直接把这个dialog禁掉试试. 测试可以用一些hook框架如xposed或者frida, 这里选择后者, 因为可能会需要做native的分析(有没有发现这个Activity的onCreate函数是native的?). frida更新速度飞快, 而且很多用法和特性都没有写到文档里, 多看看别人写的脚本也许会有很多灵感.</p>
<p>劫持函数是常规操作了:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">js</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-18" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">PlayBackActivity</span> <span class="o">=</span> <span class="nx">Java</span><span class="p">.</span><span class="nx">use</span><span class="p">(</span><span class="s2">&#34;com.zhuoyigou.dese.ui.live.activity.PlayBackActivity&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="nx">PlayBackActivity</span><span class="p">.</span><span class="nx">showTimeOutDialog</span><span class="p">.</span><span class="nx">implementation</span> <span class="o">=</span> <span class="kd">function</span><span class="p">()</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">log</span><span class="p">(</span><span class="s2">&#34;skip showTimeOutDialog()&#34;</span><span class="p">);</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
</div>
<p>重新附加进程, 打开直播间, 发现确实不弹窗了, 但是过十几秒后视频窗口仍然会自己返回. 了解安卓开发的应该都知道, Activity返回一般是调用finish函数, 不过搜了一圈发现调用的地方太多了, 懒癌发作不想一个个检查, 于是祭出frida大法, 在finish函数中查看堆栈:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-19" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>[+] skip showTimeOutDialog()
[+] skip finish()
[+] java.lang.Exception: printStackTrace here:
	at android.app.Activity.finish(Native Method)
	at com.zhuoyigou.dese.ui.live.activity.PlayBackActivity$11.handleMessage(PlayBackActivity.java:561)
	at android.os.Handler.dispatchMessage(Handler.java:102)
	at android.os.Looper.loop(Looper.java:148)
	at android.app.ActivityThread.main(ActivityThread.java:5539)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
	at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:107)</code></pre></code></pre>
</div>
<p>根据finish的堆栈查看<code>com.zhuoyigou.dese.ui.live.activity.PlayBackActivity$11</code>类中的handleMessage函数来进行验证, 确实是有这个逻辑:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-20" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kt">void</span><span class="w"> </span><span class="nf">handleMessage</span><span class="p">(</span><span class="n">Message</span><span class="w"> </span><span class="n">msg</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">switch</span><span class="p">(</span><span class="n">msg</span><span class="p">.</span><span class="na">what</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="c1">// ...</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">case</span><span class="w"> </span><span class="n">1002</span><span class="p">:</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">.</span><span class="na">mPointProgressBar</span><span class="p">.</span><span class="na">setVisibility</span><span class="p">(</span><span class="n">8</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$1400</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">).</span><span class="na">onPause</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$400</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">))</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">                </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$1500</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="p">}</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">                </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$1600</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$600</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">).</span><span class="na">sendEmptyMessageDelayed</span><span class="p">(</span><span class="n">AidConstants</span><span class="p">.</span><span class="na">EVENT_NETWORK_ERROR</span><span class="p">,</span><span class="w"> </span><span class="n">11000</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">return</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">case</span><span class="w"> </span><span class="n">AidConstants</span><span class="p">.</span><span class="na">EVENT_NETWORK_ERROR</span><span class="w"> </span><span class="cm">/*1003*/</span><span class="p">:</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$400</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">)</span><span class="w"> </span><span class="o">&amp;&amp;</span><span class="w"> </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$900</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">).</span><span class="na">isShowing</span><span class="p">())</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">                </span><span class="n">PlayBackActivity</span><span class="p">.</span><span class="na">access$900</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">).</span><span class="na">dismiss</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">this</span><span class="p">.</span><span class="na">this$0</span><span class="p">.</span><span class="na">finish</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">            </span><span class="k">return</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="c1">// ...</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>在11秒后触发事件, 直接退出窗口. 在8秒的试看后还给你3秒选择是否购买哦:) 作为验证, 我们直接对finish函数下手, 发现禁用dialog的同时禁用finish函数, 就可以绕过金币购买的限制了, 想看多久看多久.</p>
<h2 id="云存储" class="headerLink">
    <a href="#%e4%ba%91%e5%ad%98%e5%82%a8" class="header-mark"></a>云存储</h2><p>虽然现在可以无限制看片, 但正事还是要做的. 下一步看看是哪家对象存储提供了服务, 说不定还能找到硬编码的key. 在代码中瞎逛, 又(?)发现一个有趣的函数:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">java</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-21" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl"><span class="kd">private</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">initPlay</span><span class="p">(</span><span class="n">String</span><span class="w"> </span><span class="n">videoUrl</span><span class="p">,</span><span class="w"> </span><span class="n">PlayBackBean</span><span class="w"> </span><span class="n">playBackBean</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">MyLogger</span><span class="p">.</span><span class="na">jLog</span><span class="p">().</span><span class="na">e</span><span class="p">(</span><span class="s">&#34;reVideoUrl:&#34;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">videoUrl</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mVideoUrl</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">videoUrl</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">TextUtils</span><span class="p">.</span><span class="na">isEmpty</span><span class="p">(</span><span class="n">videoUrl</span><span class="p">))</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="n">showError</span><span class="p">(</span><span class="n">getString</span><span class="p">(</span><span class="n">R</span><span class="p">.</span><span class="na">string</span><span class="p">.</span><span class="na">video_invalid</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">return</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="kc">null</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">        </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">PLVideoTextureView</span><span class="p">)</span><span class="w"> </span><span class="n">findViewById</span><span class="p">(</span><span class="n">2131362384</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="p">}</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">AVOptions</span><span class="w"> </span><span class="n">options</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">AVOptions</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">options</span><span class="p">.</span><span class="na">setInteger</span><span class="p">(</span><span class="s">&#34;timeout&#34;</span><span class="p">,</span><span class="w"> </span><span class="n">StatusCodes</span><span class="p">.</span><span class="na">AUTH_DISABLED</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">options</span><span class="p">.</span><span class="na">setInteger</span><span class="p">(</span><span class="s">&#34;fast-open&#34;</span><span class="p">,</span><span class="w"> </span><span class="n">1</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">options</span><span class="p">.</span><span class="na">setInteger</span><span class="p">(</span><span class="s">&#34;mediacodec&#34;</span><span class="p">,</span><span class="w"> </span><span class="n">0</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">PLVideoTextureView</span><span class="w"> </span><span class="n">pLVideoTextureView</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">PLVideoTextureView</span><span class="w"> </span><span class="n">pLVideoTextureView2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">;</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="n">pLVideoTextureView</span><span class="p">.</span><span class="na">setDisplayAspectRatio</span><span class="p">(</span><span class="n">2</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setAVOptions</span><span class="p">(</span><span class="n">options</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mCustomController</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">CustomController</span><span class="p">(</span><span class="k">this</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setMediaController</span><span class="p">(</span><span class="k">this</span><span class="p">.</span><span class="na">mCustomController</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setVideoPath</span><span class="p">(</span><span class="n">videoUrl</span><span class="p">);</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">start</span><span class="p">();</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setOnInfoListener</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">4</span><span class="p">(</span><span class="k">this</span><span class="p">,</span><span class="w"> </span><span class="n">playBackBean</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setOnCompletionListener</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">5</span><span class="p">(</span><span class="k">this</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w">    </span><span class="k">this</span><span class="p">.</span><span class="na">mPLVideoTextureView</span><span class="p">.</span><span class="na">setOnErrorListener</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">6</span><span class="p">(</span><span class="k">this</span><span class="p">));</span><span class="w">
</span></span></span><span class="line"><span class="cl"><span class="w"></span><span class="p">}</span></span></span></code></pre>
</div>
<p>videoUrl? 劫持该函数并打印出来, url地址如下(已打码):</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-22" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>http://qiniuvod.xxxxx.com/recordings/z1.xxxxx.qn1546622961492A/0_1546635114.mp4?sign=b6c6587f1794a14c250e143f28e07620&amp;t=5c303623</code></pre></code></pre>
</div>
<p>这个链接使用wget竟然可以<strong>直接下载</strong>, 下载结果就是mp4视频文件, 也就是播放的回放视频. 除了mp4还有m3u8格式的链接. m3u8链接可以直接用ffmpeg下载:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">sh</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-23" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><span class="line"><span class="cl">ffmpeg -i http://xxx.com/vid.m3u8 -c copy vid.mp4</span></span></code></pre>
</div>
<p>言归正传, 从这里的url地址看到了熟悉的qiniu, 莫非是七牛云? 查看代码发现确实是用了七牛的安卓SDK. 一年前正好写了个七牛云的对象存储管理命令行工具<a href="https://github.com/evilpan/qncli" target="_blank" rel="noopener noreferrer">qncli</a>, 所以对七牛云还是有了解的. 七牛云本身有key和secret, 但是是使用token来对bucket进行访问. 对于客户端而言, 建议的安全做法也是使用服务器下发token的方式来操作.</p>
<p>通过查看代码, 发现该url也确实是服务端下发的. 一般来说, 七牛云的私有bucket会通过对超时与资源一起签名来控制对内容的访问, 格式为:</p>
<div class="code-block highlight is-open show-line-numbers  tw-group tw-my-2">
  <div class="
    
    tw-flex 
    tw-flex-row
    tw-flex-1 
    tw-justify-between 
    tw-w-full tw-bg-bgColor-secondary
    ">      
    <button 
      class="
        code-block-button
        tw-mx-2 
        tw-flex
        tw-flex-row
        tw-flex-1"
      aria-hidden="true">
          <div class="group-[.is-open]:tw-rotate-90 tw-transition-[transform] tw-duration-500 tw-ease-in-out print:!tw-hidden tw-w-min tw-h-min tw-my-1 tw-mx-1"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M285.476 272.971L91.132 467.314c-9.373 9.373-24.569 9.373-33.941 0l-22.667-22.667c-9.357-9.357-9.375-24.522-.04-33.901L188.505 256 34.484 101.255c-9.335-9.379-9.317-24.544.04-33.901l22.667-22.667c9.373-9.373 24.569-9.373 33.941 0L285.475 239.03c9.373 9.372 9.373 24.568.001 33.941z"/></svg></div>
          <p class="tw-select-none !tw-my-1">text</p>
      </button>

   <div class="tw-flex">
      <button 
        class="
          line-number-button
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.show-line-numbers]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle line numbers"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M61.77 401l17.5-20.15a19.92 19.92 0 0 0 5.07-14.19v-3.31C84.34 356 80.5 352 73 352H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8h22.83a157.41 157.41 0 0 0-11 12.31l-5.61 7c-4 5.07-5.25 10.13-2.8 14.88l1.05 1.93c3 5.76 6.29 7.88 12.25 7.88h4.73c10.33 0 15.94 2.44 15.94 9.09 0 4.72-4.2 8.22-14.36 8.22a41.54 41.54 0 0 1-15.47-3.12c-6.49-3.88-11.74-3.5-15.6 3.12l-5.59 9.31c-3.72 6.13-3.19 11.72 2.63 15.94 7.71 4.69 20.38 9.44 37 9.44 34.16 0 48.5-22.75 48.5-44.12-.03-14.38-9.12-29.76-28.73-34.88zM496 224H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zm0-160H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16V80a16 16 0 0 0-16-16zm0 320H176a16 16 0 0 0-16 16v32a16 16 0 0 0 16 16h320a16 16 0 0 0 16-16v-32a16 16 0 0 0-16-16zM16 160h64a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H64V40a8 8 0 0 0-8-8H32a8 8 0 0 0-7.14 4.42l-8 16A8 8 0 0 0 24 64h8v64H16a8 8 0 0 0-8 8v16a8 8 0 0 0 8 8zm-3.91 160H80a8 8 0 0 0 8-8v-16a8 8 0 0 0-8-8H41.32c3.29-10.29 48.34-18.68 48.34-56.44 0-29.06-25-39.56-44.47-39.56-21.36 0-33.8 10-40.46 18.75-4.37 5.59-3 10.84 2.8 15.37l8.58 6.88c5.61 4.56 11 2.47 16.12-2.44a13.44 13.44 0 0 1 9.46-3.84c3.33 0 9.28 1.56 9.28 8.75C51 248.19 0 257.31 0 304.59v4C0 316 5.08 320 12.09 320z"/></svg></button>

      <button 
        class="
          wrap-code-button
          tw-select-none 
          tw-mx-2 
          tw-hidden 
          group-[.is-open]:tw-block 
          group-[.is-wrap]:tw-text-fgColor-link 
          print:!tw-hidden" 
        title="Toggle code wrap"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M16 132h416c8.837 0 16-7.163 16-16V76c0-8.837-7.163-16-16-16H16C7.163 60 0 67.163 0 76v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16zm0 160h416c8.837 0 16-7.163 16-16v-40c0-8.837-7.163-16-16-16H16c-8.837 0-16 7.163-16 16v40c0 8.837 7.163 16 16 16z"/></svg></button>
      
      <button 
        class="
          copy-code-button
          tw-select-none
          tw-mx-2 
          tw-hidden
          group-[.is-open]:tw-block
          hover:tw-text-fgColor-link 
          print:!tw-hidden"
        title="Copy code">
          <span class="copy-icon tw-block"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M433.941 65.941l-51.882-51.882A48 48 0 0 0 348.118 0H176c-26.51 0-48 21.49-48 48v48H48c-26.51 0-48 21.49-48 48v320c0 26.51 21.49 48 48 48h224c26.51 0 48-21.49 48-48v-48h80c26.51 0 48-21.49 48-48V99.882a48 48 0 0 0-14.059-33.941zM266 464H54a6 6 0 0 1-6-6V150a6 6 0 0 1 6-6h74v224c0 26.51 21.49 48 48 48h96v42a6 6 0 0 1-6 6zm128-96H182a6 6 0 0 1-6-6V54a6 6 0 0 1 6-6h106v88c0 13.255 10.745 24 24 24h88v202a6 6 0 0 1-6 6zm6-256h-64V48h9.632c1.591 0 3.117.632 4.243 1.757l48.368 48.368a6 6 0 0 1 1.757 4.243V112z"/></svg></span>
          <span class="check-icon tw-hidden"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M173.898 439.404l-166.4-166.4c-9.997-9.997-9.997-26.206 0-36.204l36.203-36.204c9.997-9.998 26.207-9.998 36.204 0L192 312.69 432.095 72.596c9.997-9.997 26.207-9.997 36.204 0l36.203 36.204c9.997 9.997 9.997 26.206 0 36.204l-294.4 294.401c-9.998 9.997-26.207 9.997-36.204-.001z"/></svg></span>
      </button>
        
      <button 
        class="
          tw-select-none 
          tw-mx-2 
          tw-block 
          group-[.is-open]:tw-hidden 
          print:!tw-hidden" 
        disabled
        aria-hidden="true"><svg class="icon"
    xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M328 256c0 39.8-32.2 72-72 72s-72-32.2-72-72 32.2-72 72-72 72 32.2 72 72zm104-72c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72zm-352 0c-39.8 0-72 32.2-72 72s32.2 72 72 72 72-32.2 72-72-32.2-72-72-72z"/></svg></button>
    </div>
  </div>
  <pre style="counter-reset: codeblock;" class="tw-block tw-m-0 tw-p-0"><code 
    id="codeblock-id-24" 
    class="
      chroma 
      !tw-block 
      tw-p-0
      tw-m-0
      tw-transition-[max-height] 
      tw-duration-500 
      tw-ease-in-out 
      group-[.is-closed]:!tw-max-h-0 
      group-[.is-wrap]:tw-text-wrap
      tw-overflow-y-hidden
      tw-overflow-x-auto
      tw-scrollbar-thin
      "><pre tabindex="0"><code>http://qiniu.example.com/resource.txt?e=1546686297&amp;token=xxx</code></pre></code></pre>
</div>
<p>不知为何上述链接的格式却不是传统私有链接, 也许是其他产品也说不定, 有了解的朋友也可以留言同步一下.</p>
<h2 id="misc" class="headerLink">
    <a href="#misc" class="header-mark"></a>MISC</h2><p>除了云存储, 该直播软件与很多小众直播一样, 使用了三方直播SDK减少开发量, 如某拍SDK. 同时集成了多家厂商的地址定位, 猜测是为了做LBS社交, 而主页中出现的“同城”banner也部分印证了我们的想法. 至于同城见面是做什么, 那就自己想象吧.</p>
<p>该APP同时也做了分享赚金币的功能, 使用ShareSDK, 支持QQ、微信、微博、豆瓣等知名社交网站, 这也解释了为什么明明这个低调得都不进入百度收录的APP, 却拥有不少的用户量. 上面也说过, 不论直播还是回放, 都是需要金币付费访问的. 而里面还可以发布非直播的视频, 有偿提供下载, 俨然成长为了一个小视频交易社区.</p>
<p>根据平台提供的统计数据, 充值用户的“土豪榜”如下:</p>
<p><img class="tw-inline" loading="lazy" src='/img/2019-01-05-reverse-live-porn-app/6.png?t=0'   alt="user"  ></p>
<p>另外通过技术手段, 发现该APP的注册用户数在25万左右, 虽然量不多, 但都是实打实的付费用户啊! 按照金币的平均价格以及用户的付费情况估算, 排除部分托儿刷榜, 保守估计该平台在18年收入也是千万级. 这还只是单个APP明面上的数据, 实际上一个公司背后往往关联数十个平台, 拔出萝卜带出泥. 由于该平台本身并没有做什么伤天害理的事情, 就点到为止吧.</p>
<h1 id="小结" class="headerLink">
    <a href="#%e5%b0%8f%e7%bb%93" class="header-mark"></a>小结</h1><p>本文出于无聊以及猎奇的心理, 加上手痒, 就跟这个灰色直播软件玩了半天. 顺便记录了一下Android逆向的一些常用操作, 有些技术写出来确实印象深刻一点. 俗话说, 猎人要随时保持自己的技能锋利, 这对于安全研究人员也是一样的. 安全技术也是日新月异, 闲时也要把握好各种实战机会.</p>
<h1 id="后记" class="headerLink">
    <a href="#%e5%90%8e%e8%ae%b0" class="header-mark"></a>后记</h1><p>在使用该直播软件的过程中, 惊讶地发现里面有很部分用户竟还是在校<strong>学生</strong>, 包括用户和主播. 通过某种手段添加其中一个主播聊天得知, SM行业“水很深”, 除了直播间收礼物外, 主播一般还会将高质量用户引流到其他社交平台(刷“飞机”加微信). 然后私底下会视情况进行现实调教. 用该主播的话说, ”一天2个或者3个, 元旦那天最多, 一天有8个”, 这每一“个”的收费自然也是不低的, 内容大概有XX、XX和XX, 重口味一点的有XX、XX等&hellip;</p>
<p>对于该“圈子”的是非且不去谈, 这个公司游走在法律边缘, 还致未成年人的身心健康于无物, 老子动画片(进击的巨人)都看不了, 这种直播竟没有相关部门管束? 对于成年的观众, 大家都有辨别是非的能力, 就不多说了吧. 至于主播, 很多人就是作为工作或者兼职, 赚的也是辛苦钱, 也不多说了吧. 毕竟, 言多必失, 你懂的.</p>]]></description>
</item></channel>
</rss>
