Android APK 在32bit 和64bit 的区别问题

Posted 2021-01-30 kwincaq

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Android APK 在32bit 和64bit 的区别问题相关的知识，希望对你有一定的参考价值。

目前64bit android系统也慢慢的多了，看到也有apk声称支持64bit system，然后就往里面打包搞了个arm64-v8a 目录，放了个64bit的so，但是apk代码里面却不按规范去load so ，导致一系列 file not found 异常。

apk lib目录:

先看下apk中的lib打包的目录：
技术分享图片
依次代表不同类型的cpu

PMS安装路径：//blog.csdn.net/sergeycao

pms install 流程比较繁杂，只关注so相关的scanPackageDirtyLI函数中：

<code class="hljs r has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">
private PackageParser.Package scanPackageDirtyLI(PackageParser.Package pkg, int parseFlags,
            int scanFlags, long currentTime, UserHandle user) throws PackageManagerException {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>
             //invoke installer to do the actual installation  //作为外部apk 创建data目录相关项
             //frameworks
ativecmdsinstalldcommands.c  install()中创建
                int ret = **createDataDirsLI**(pkgName, pkg.applicationInfo.uid,
                                           pkg.applicationInfo.seinfo);
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (isSystemApp(pkg) && !isUpdatedSystemApp(pkg)) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>

           setBundledAppAbisAndRoots(pkg, pkgSetting);

            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>

           setNativeLibraryPaths(pkg);  

    }
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>
    {
    setNativeLibraryPaths(pkg);
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (isAsec) {
                        copyRet = NativeLibraryHelper.findSupportedAbi(handle, abiList);
                    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
                        copyRet = NativeLibraryHelper.copyNativeBinariesForSupportedAbi(handle,
                                nativeLibraryRoot, abiList, useIsaSpecificSubdirs);
                    }
    setNativeLibraryPaths(pkg);
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (DEBUG_INSTALL) Slog.i(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Linking native library dir for "</span> + path);
            final int[] userIds = sUserManager.getUserIds();
            synchronized (mInstallLock) {
                // Create a native <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">library</span> symlink only <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> we have native libraries
                // and <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> the native libraries are <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">32</span> bit libraries. We do not provide
                // this symlink <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">64</span> bit libraries.
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (pkg.applicationInfo.primaryCpuAbi != null &&
                        **!VMRuntime.is64BitAbi(pkg.applicationInfo.primaryCpuAbi)**) {
                    final String nativeLibPath = pkg.applicationInfo.nativeLibraryDir;
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (int userId : userIds) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (mInstaller.linkNativeLibraryDirectory(pkg.packageName, nativeLibPath, userId) < <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)    {
                            throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR,
                                    <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Failed linking native library dir (user="</span> + userId + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">")"</span>);
                        }
                    }
                }
            }

    }
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li></ul>

看下system app 的安装配置函数 setBundledAppAbisAndRoots：

//blog.csdn.net/sergeycao

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * Calculate the abis and roots for a bundled app. These can uniquely
     * be determined from the contents of the system partition, i.e whether
     * it contains 64 or 32 bit shared libraries etc. We do not validate any
     * of this information, and instead assume that the system was built
     * sensibly.
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setBundledAppAbisAndRoots</span>(PackageParser.Package pkg,
                                           PackageSetting pkgSetting) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String apkName = deriveCodePathName(pkg.applicationInfo.getCodePath());

        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// If "/system/lib64/apkname" exists, assume that is the per-package</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// native library directory to use; otherwise use "/system/lib/apkname".</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String apkRoot = calculateBundledApkRoot(pkg.applicationInfo.sourceDir);
        setBundledAppAbi(pkg, apkRoot, apkName);
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// pkgSetting might be null during rescan following uninstall of updates</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// to a bundled app, so accommodate that possibility.  The settings in</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// that case will be established later from the parsed package.</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// If the settings aren‘t null, sync them up with what we‘ve just derived.</span>
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// note that apkRoot isn‘t stored in the package settings.</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (pkgSetting != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
            pkgSetting.primaryCpuAbiString = pkg.applicationInfo.primaryCpuAbi;
            pkgSetting.secondaryCpuAbiString = pkg.applicationInfo.secondaryCpuAbi;
        }
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>

主要是在setBundledAppAbi中：

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * Deduces the ABI of a bundled app and sets the relevant fields on the
     * parsed pkg object.
     *
     *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> apkRoot the root of the installed apk, something like {@code /system} or {@code /oem}
     *        under which system libraries are installed.
     *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> apkName the name of the installed package.
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setBundledAppAbi</span>(PackageParser.Package pkg, String apkRoot, String apkName) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File codeFile = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(pkg.codePath);
...
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (has64BitLibs && !has32BitLibs) {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// The package has 64 bit libs, but not 32 bit libs. Its primary</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ABI should be 64 bit. We can safely assume here that the bundled</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// native libraries correspond to the most preferred ABI in the list.</span>

            pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
            pkg.applicationInfo.secondaryCpuAbi = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (has32BitLibs && !has64BitLibs) {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// The package has 32 bit libs but not 64 bit libs. Its primary</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ABI should be 32 bit.</span>

            pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
            pkg.applicationInfo.secondaryCpuAbi = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (has32BitLibs && has64BitLibs) {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// The application has both 64 and 32 bit bundled libraries. We check</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// here that the app declares multiArch support, and warn if it doesn‘t.</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// We will be lenient here and record both ABIs. The primary will be the</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ABI that‘s higher on the list, i.e, a device that‘s configured to prefer</span>
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 64 bit apps will see a 64 bit primary ABI,</span>

            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_MULTIARCH) == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
                Slog.e(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Package: "</span> + pkg + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">" has multiple bundled libs, but is not multiarch."</span>);
            }

            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (VMRuntime.is64BitInstructionSet(getPreferredInstructionSet())) {
                pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
                pkg.applicationInfo.secondaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
            } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
                pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
                pkg.applicationInfo.secondaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
            }
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
            pkg.applicationInfo.primaryCpuAbi = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
            pkg.applicationInfo.secondaryCpuAbi = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        }
 }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li></ul>

根据file 查找确定primaryCpuAbi secondaryCpuAbi 变量值，这个也就决定了这个 apk 由64bit 还是32bit 的zygote去fork 还有nativelibrary 查找的path

其中nativelibrary的几个主要函数 setNativeLibraryPaths：

//blog.csdn.net/sergeycao

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * Derive and set the location of native libraries for the given package,
     * which varies depending on where and how the package was installed.
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setNativeLibraryPaths</span>(PackageParser.Package pkg) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ApplicationInfo info = pkg.applicationInfo;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String codePath = pkg.codePath;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File codeFile = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(codePath);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> bundledApp = isSystemApp(info) && !isUpdatedSystemApp(info);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> asecApp = isForwardLocked(info) || isExternal(info);

        info.nativeLibraryRootDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        info.nativeLibraryRootRequiresIsa = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
        info.nativeLibraryDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        info.secondaryNativeLibraryDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;

        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (isApkFile(codeFile)) {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Monolithic install</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bundledApp) {
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// If "/system/lib64/apkname" exists, assume that is the per-package</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// native library directory to use; otherwise use "/system/lib/apkname".</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String apkRoot = calculateBundledApkRoot(info.sourceDir);
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> is64Bit = VMRuntime.is64BitInstructionSet(
                        getPrimaryInstructionSet(info));

                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// This is a bundled system app so choose the path based on the ABI.</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// if it‘s a 64 bit abi, use lib64 otherwise use lib32. Note that this</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// is just the default path.</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String apkName = deriveCodePathName(codePath);
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String libDir = is64Bit ? LIB64_DIR_NAME : LIB_DIR_NAME;
                info.nativeLibraryRootDir = Environment.buildPath(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(apkRoot), libDir,
                        apkName).getAbsolutePath();

                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (info.secondaryCpuAbi != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String secondaryLibDir = is64Bit ? LIB_DIR_NAME : LIB64_DIR_NAME;
                    info.secondaryNativeLibraryDir = Environment.buildPath(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(apkRoot),
                            secondaryLibDir, apkName).getAbsolutePath();
                }
            } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (asecApp) {
                info.nativeLibraryRootDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(codeFile.getParentFile(), LIB_DIR_NAME)
                        .getAbsolutePath();
            } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String apkName = deriveCodePathName(codePath);
                info.nativeLibraryRootDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(mAppLib32InstallDir, apkName)
                        .getAbsolutePath();
            }

            info.nativeLibraryRootRequiresIsa = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
            info.nativeLibraryDir = info.nativeLibraryRootDir;
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Cluster install</span>
            info.nativeLibraryRootDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(codeFile, LIB_DIR_NAME).getAbsolutePath();
            info.nativeLibraryRootRequiresIsa = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;

            info.nativeLibraryDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(info.nativeLibraryRootDir,
                    getPrimaryInstructionSet(info)).getAbsolutePath();

            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (info.secondaryCpuAbi != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
                info.secondaryNativeLibraryDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(info.nativeLibraryRootDir,
                        VMRuntime.getInstructionSet(info.secondaryCpuAbi)).getAbsolutePath();
            }
        }
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li></ul>

根据pkg application info 来确定nativelibrarydir 依赖info中的 info.primaryCpuAbi

<code class="hljs cs has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> String <span class="hljs-title" style="box-sizing: border-box;">getPrimaryInstructionSet</span>(ApplicationInfo info) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (info.primaryCpuAbi == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> getPreferredInstructionSet();
        }

        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> VMRuntime.getInstructionSet(info.primaryCpuAbi);
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>

非system apk 会调用 NativeLibraryHelper 的 findSupportedAbi 去解析 .apk 文件，根据系统suportabilist 去查找 lib目录下的打包子目录找到匹配的abi

向文章开头的那个 lib目录，在64bit 机器上suportabilist为：

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String[] SUPPORTED_ABIS = getStringList(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ro.product.cpu.abilist"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">","</span>);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

<code class="hljs ruby has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">[email protected]<span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">:/</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># getprop ro.product.cpu.abilist                                 </span>
arm64-v8a,armeabi-v7a,armeabi</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

会匹配arm64-v8a 赋值给 info.primaryCpuAbi

copyNativeBinariesForSupportedAbi 会去copy 前面匹配的lib 目录到本地

最后设置NativeLibraryPaths ，
如果匹配的是64bit的，也就是arm64-v8a 那么就不为/data/data/../lib 建立软链接，这是与32bit 不同的地方

system.loadlibrary

作为动态库加载的标准接口，直接看实现：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">loadLibrary</span>(String libName) {
        Runtime.getRuntime().loadLibrary(libName, VMStack.getCallingClassLoader());
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

到Runtime.java中：

<code class="hljs javascript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*
     * Searches for and loads the given shared library using the given ClassLoader.
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> loadLibrary(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> libraryName, ClassLoader loader) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (loader != <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>) {
            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> filename = loader.findLibrary(libraryName);
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (filename == <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>) {
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// It‘s not necessarily true that the ClassLoader used</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// System.mapLibraryName, but the default setup does, and it‘s</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// misleading to say we didn‘t find "libMyLibrary.so" when we</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// actually searched for "liblibMyLibrary.so.so".</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UnsatisfiedLinkError(loader + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">" couldn‘t find ""</span> +
                                               System.mapLibraryName(libraryName) + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"""</span>);
            }
            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> error = doLoad(filename, loader);
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (error != <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>) {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UnsatisfiedLinkError(error);
            }
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
        }

        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> filename = System.mapLibraryName(libraryName);
        List<<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span>> candidates = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ArrayList<<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span>>();
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> lastError = <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> directory : mLibPaths) {
            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> candidate = directory + filename;
            candidates.add(candidate);

            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (IoUtils.canOpenReadOnly(candidate)) {
                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> error = doLoad(candidate, loader);
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (error == <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>) {
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// We successfully loaded the library. Job done.</span>
                }
                lastError = error;
            }
        }

        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lastError != <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UnsatisfiedLinkError(lastError);
        }
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UnsatisfiedLinkError(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Library "</span> + libraryName + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">" not found; tried "</span> + candidates);
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li></ul>

这里的 ClassLoader loader 实际上会在 apk启动的时候初始化好一些相关的子类父类还有参数

大体记录一下启动时初始流程：

<code class="hljs scala has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">ActivityThread.java   - handleBindApplication  
 <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ContextImpl appContext = ContextImpl.createAppContext(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, data.info);
  LoadedApk pi = getPackageInfo(instrApp, data.compatInfo,
                    appContext.getClassLoader(), <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>);


ContextImpl.java  -getClassLoader()
LoadedApk.java    -getClassLoader()     ：  mLibDir = aInfo.nativeLibraryDir;
mClassLoader = ApplicationLoaders.getDefault().getClassLoader(zip, lib,
                        mBaseClassLoader);
ApplicationLoaders.java    -getClassLoader(...)
 PathClassLoader pathClassloader = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> PathClassLoader(zip, libPath, parent);   <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//这里的libPath 就是上面传下来的aInfo.nativeLibraryDir</span>

public <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">PathClassLoader</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">BaseDexClassLoader</span></span>
public <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">BaseDexClassLoader</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ClassLoader</span></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

loader.findLibrary(libraryName);

<code class="hljs applescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    /**
     * Finds <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> named native code library <span class="hljs-function_start" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">on</span></span> any <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> library
     * directories pointed <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">at</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">by</span> this instance. This will find <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span>
     * one <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">in</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> earliest listed directory, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">ignoring</span> any <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">that</span> are <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">not</span>
     * readable regular files.
     *
     * @<span class="hljs-constant" style="box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> complete <span class="hljs-command" style="box-sizing: border-box;">path to</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> library <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">or</span> {@code null} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> no
     * library was found
     */
    public String findLibrary(String libraryName) {
        String fileName = System.mapLibraryName(libraryName);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (File directory : nativeLibraryDirectories) {
            String path = new File(directory, fileName).getPath();
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (IoUtils.canOpenReadOnly(path)) {
<span class="hljs-command" style="box-sizing: border-box;">                return</span> path;
            }
        }
<span class="hljs-command" style="box-sizing: border-box;">        return</span> null;
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li></ul>

这里的nativeLibraryDirectories 即为前面一系列构造时设置了值其中就有 aInfo.nativeLibraryDir

后面的逻辑就不去叙述了，根据名字在这个目录下去找，然后调用到本地JNI 最终调用 dlopen 加载打开so，必须是相同位数，而这个关乎当前进程是属于64bit 还是 32bit，这个会在zygote fork时区分，同样也是由PMS解析时得到的 info.primaryCpuAbi

AMS 请求zygote fork app process选择

只关心相关代码 startProcessLocked函数：

<code class="hljs r has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    private final void startProcessLocked(ProcessRecord app, String hostingType,
            String hostingNameStr, String abiOverride, String entryPoint, String[] entryPointArgs) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>

 String requiredAbi = (abiOverride != null) ? abiOverride : app.info.primaryCpuAbi;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (requiredAbi == null) {
                requiredAbi = Build.SUPPORTED_ABIS[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];
            }

            String instructionSet = null;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (app.info.primaryCpuAbi != null) {
                instructionSet = VMRuntime.getInstructionSet(app.info.primaryCpuAbi);
            }

            app.gids = gids;
            app.requiredAbi = requiredAbi;
            app.instructionSet = instructionSet;

            // Start the process.  It will either succeed and <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> a result containing
            // the PID of the new process, or <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> throw a RuntimeException.
            boolean isActivityProcess = (entryPoint == null);
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (entryPoint == null) entryPoint = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android.app.ActivityThread"</span>;
            checkTime(startTime, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"startProcess: asking zygote to start proc"</span>);
            Process.ProcessStartResult startResult = Process.start(entryPoint,
                    app.processName, uid, uid, gids, debugFlags, mountExternal,
                    app.info.targetSdkVersion, app.info.seinfo, requiredAbi, instructionSet,
                    app.info.dataDir, entryPointArgs);
            checkTime(startTime, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"startProcess: returned from zygote!"</span>);

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li></ul>

Process中真正的socket 请求实现：

<code class="hljs scss has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">return <span class="hljs-function" style="box-sizing: border-box;">zygoteSendArgsAndGetResult(<span class="hljs-function" style="box-sizing: border-box;">openZygoteSocketIfNeeded(abi)</span>, argsForZygote)</span>;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

openZygoteSocketIfNeeded 会根据传下来的abi 去选择通信的socket

而在64bit 机器上，启动时会启动两个 zygote service ，用于接收 64 32 的apk 请求：

<code class="hljs livecodeserver has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: ‘Source Code Pro‘, monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">service zygote /<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>/bin/app_process64 -Xzygote /<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>/bin <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">--zygote --start-system-server --socket-name=zygote</span>
    class main
    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">socket</span> zygote stream <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">660</span> root <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>
    onrestart <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">write</span> /sys/android_power/request_state wake
    onrestart <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">write</span> /sys/power/state <span class="hljs-command" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">on</span></span>
    onrestart restart media
    onrestart restart netd

service zygote_secondary /<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>/bin/app_process32 -Xzygote /<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>/bin <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">--zygote --socket-name=zygote_secondary</span>
    class main
    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">socket</span> zygote_secondary stream <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">660</span> root <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">system</span>
    onrestart restart zygote</code>

pms install 流程比较繁杂，只关注so相关的scanpackageDirtyLI函数中：

private PackageParser.Package scanPackageDirtyLI(PackageParser.Package pkg, int parseFlags, int scanFlags, long currentTime, UserHandle user) throws PackageManagerException { ... //invoke installer to do the actual installation //作为外部apk 创建data目录相关项 //frameworks ativecmdsinstalldcommands.c install()中创建 int ret = **createDataDirsLI**(pkgName, pkg.applicationInfo.uid, pkg.applicationInfo.seinfo); ... if (isSystemApp(pkg) && !isupdatedSystemApp(pkg)) { ... setBundledAppAbisAndRoots(pkg, pkgSetting); ... setNativeLibraryPaths(pkg); } else { setNativeLibraryPaths(pkg); ... if (isAsec) { copyRet = NativeLibraryHelper.findSupportedAbi(handle, abiList); } else { copyRet = NativeLibraryHelper.copyNativeBinariesForSupportedAbi(handle, nativeLibraryRoot, abiList, useIsaSpecificSubdirs); } setNativeLibraryPaths(pkg); if (DEBUG_INSTALL) Slog.i(TAG, "Linking native library dir for " + path); final int[] userIds = sUserManager.getUserIds(); synchronized (mInstallLock) { // Create a native library symlink only if we have native libraries // and if the native libraries are 32 bit libraries. We do not provide // this symlink for 64 bit libraries. if (pkg.applicationInfo.primaryCpuAbi != null && **!VMRuntime.is64BitAbi(pkg.applicationInfo.primaryCpuAbi)**) { final String nativeLibPath = pkg.applicationInfo.nativeLibraryDir; for (int userId : userIds) { if (mInstaller.linkNativeLibraryDirectory(pkg.packageName, nativeLibPath, userId) < 0) { throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR, "Failed linking native library dir (user=" + userId + ")"); } } } } } }

看下system app 的安装配置函数 setBundledAppAbisAndRoots：

/** * Calculate the abis and roots for a bundled app. These can uniquely * be determined from the contents of the system partition, i.e whether * it contains 64 or 32 bit shared libraries etc. We do not validate any * of this information, and instead assume that the system was built * sensibly. */ private void setBundledAppAbisAndRoots(PackageParser.Package pkg, PackageSetting pkgSetting) { final String apkName = deriveCodePathName(pkg.applicationInfo.getCodePath()); // If "/system/lib64/apkname" exists, assume that is the per-package // native library directory to use; otherwise use "/system/lib/apkname". final String apkRoot = calculateBundledApkRoot(pkg.applicationInfo.sourceDir); setBundledAppAbi(pkg, apkRoot, apkName); // pkgSetting might be null during rescan following uninstall of updates // to a bundled app, so accommodate that possibility. The settings in // that case will be established later from the parsed package. // // If the settings aren‘t null, sync them up with what we‘ve just derived. // note that apkRoot isn‘t stored in the package settings. if (pkgSetting != null) { pkgSetting.primaryCpuAbiString = pkg.applicationInfo.primaryCpuAbi; pkgSetting.secondaryCpuAbiString = pkg.applicationInfo.secondaryCpuAbi; } }

主要是在setBundledAppAbi中：

/** * Deduces the ABI of a bundled app and sets the relevant fields on the * parsed pkg object. * * @param apkRoot the root of the installed apk, something like {@code /system} or {@code /oem} * under which system libraries are installed. * @param apkName the name of the installed package. */ private static void setBundledAppAbi(PackageParser.Package pkg, String apkRoot, String apkName) { final File codeFile = new File(pkg.codePath); ... if (has64BitLibs && !has32BitLibs) { // The package has 64 bit libs, but not 32 bit libs. Its primary // ABI should be 64 bit. We can safely assume here that the bundled // native libraries correspond to the most preferred ABI in the list. pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[0]; pkg.applicationInfo.secondaryCpuAbi = null; } else if (has32BitLibs && !has64BitLibs) { // The package has 32 bit libs but not 64 bit libs. Its primary // ABI should be 32 bit. pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[0]; pkg.applicationInfo.secondaryCpuAbi = null; } else if (has32BitLibs && has64BitLibs) { // The application has both 64 and 32 bit bundled libraries. We check // here that the app declares multiArch support, and warn if it doesn‘t. // // We will be lenient here and record both ABIs. The primary will be the // ABI that‘s higher on the list, i.e, a device that‘s configured to prefer // 64 bit apps will see a 64 bit primary ABI, if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_MULTIARCH) == 0) { Slog.e(TAG, "Package: " + pkg + " has multiple bundled libs, but is not multiarch."); } if (VMRuntime.is64BitInstructionSet(getPreferredInstructionSet())) { pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[0]; pkg.applicationInfo.secondaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[0]; } else { pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_32_BIT_ABIS[0]; pkg.applicationInfo.secondaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[0]; } } else { pkg.applicationInfo.primaryCpuAbi = null; pkg.applicationInfo.secondaryCpuAbi = null; } }

根据file 查找确定primaryCpuAbi secondaryCpuAbi 变量值，这个也就决定了这个 apk 由64bit 还是32bit 的zygote去fork 还有nativelibrary 查找的path

其中nativelibrary的几个主要函数 setNativeLibraryPaths：

/** * Derive and set the location of native libraries for the given package, * which varies depending on where and how the package was installed. */ private void setNativeLibraryPaths(PackageParser.Package pkg) { final ApplicationInfo info = pkg.applicationInfo; final String codePath = pkg.codePath; final File codeFile = new File(codePath); final boolean bundledApp = isSystemApp(info) && !isUpdatedSystemApp(info); final boolean asecApp = isForwardLocked(info) || isExternal(info); info.nativeLibraryRootDir = null; info.nativeLibraryRootRequiresIsa = false; info.nativeLibraryDir = null; info.secondaryNativeLibraryDir = null; if (isApkFile(codeFile)) { // Monolithic install if (bundledApp) { // If "/system/lib64/apkname" exists, assume that is the per-package // native library directory to use; otherwise use "/system/lib/apkname". final String apkRoot = calculateBundledApkRoot(info.sourceDir); final boolean is64Bit = VMRuntime.is64BitInstructionSet( getPrimaryInstructionSet(info)); // This is a bundled system app so choose the path based on the ABI. // if it‘s a 64 bit abi, use lib64 otherwise use lib32. Note that this // is just the default path. final String apkName = deriveCodePathName(codePath); final String libDir = is64Bit ? LIB64_DIR_NAME : LIB_DIR_NAME; info.nativeLibraryRootDir = Environment.buildPath(new File(apkRoot), libDir, apkName).getAbsolutePath(); if (info.secondaryCpuAbi != null) { final String secondaryLibDir = is64Bit ? LIB_DIR_NAME : LIB64_DIR_NAME; info.secondaryNativeLibraryDir = Environment.buildPath(new File(apkRoot), secondaryLibDir, apkName).getAbsolutePath(); } } else if (asecApp) { info.nativeLibraryRootDir = new File(codeFile.getParentFile(), LIB_DIR_NAME) .getAbsolutePath(); } else { final String apkName = deriveCodePathName(codePath); info.nativeLibraryRootDir = new File(mAppLib32InstallDir, apkName) .getAbsolutePath(); } info.nativeLibraryRootRequiresIsa = false; info.nativeLibraryDir = info.nativeLibraryRootDir; } else { // Cluster install info.nativeLibraryRootDir = new File(codeFile, LIB_DIR_NAME).getAbsolutePath(); info.nativeLibraryRootRequiresIsa = true; info.nativeLibraryDir = new File(info.nativeLibraryRootDir, getPrimaryInstructionSet(info)).getAbsolutePath(); if (info.secondaryCpuAbi != null) { info.secondaryNativeLibraryDir = new File(info.nativeLibraryRootDir, VMRuntime.getInstructionSet(info.secondaryCpuAbi)).getAbsolutePath(); } } }

根据pkg application info 来确定nativelibrarydir 依赖info中的 info.primaryCpuAbi

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