Android APK 在32bit 和64bit 的区别问题

Posted 2020-06-30 曹纪乾

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：
lib
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\\native\\cmds\\installd\\commands.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;">root@<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：

android是32-bit系统还是64-bit系统

由于Google Play最近发布了公告，因此将64位兼容性与32位android apk集成在一起

Cordova App 无法使用人行横道插件安装 64Bit APK

检测目标程序ELF bit是32还是64

32bit和64bit有啥区别？