Android-6.0之PMS安装APK下篇

本文转载于：http://www.iloveandroid.net/2016/06/20/Android_PackageManagerService-2/

安装一个apk分为：检查权限，复制文件，装在应用。前面分析了前两步，现在开始分析app的装载。

这一步中主要完成将dex转换为ART虚拟机的oat格式的执行文件，并为应用创建数据沙箱目录，最后把应用的信息装载进PMS的数据结构中去。

在前面的处理MCS_BOUND时调用的HandlerParams的startCopy方法中

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final boolean startCopy() {           boolean res;           try {    ...........................               if (++mRetries > MAX_RETRIES) {        ....................................................                   return false;               } else {                   handleStartCopy();                   res = true;               }           } catch (RemoteException e) {..............................           }           handleReturnCode();           return res;       }

可以知道当复制完文件之后，会调用InstallParams的handleReturnCode方法：

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void handleReturnCode() {           // If mArgs is null, then MCS couldn't be reached. When it           // reconnects, it will try again to install. At that point, this           // will succeed.           if (mArgs != null) {               processPendingInstall(mArgs, mRet);           }       }

代码如下：

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private void processPendingInstall(final InstallArgs args, final int currentStatus) {       // Queue up an async operation since the package installation may take a little while.       mHandler.post(new Runnable() {           public void run() {               mHandler.removeCallbacks(this);                // Result object to be returned               PackageInstalledInfo res = new PackageInstalledInfo();               res.returnCode = currentStatus;               res.uid = -1;               res.pkg = null;               res.removedInfo = new PackageRemovedInfo();               if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {                    //一般情况下，什么都不会做的                   args.doPreInstall(res.returnCode);                   synchronized (mInstallLock) {                       installPackageLI(args, res);                   }                   args.doPostInstall(res.returnCode, res.uid);               }            .....................................            /* 省略关于云备份的代码*/            .....................................               if (!doRestore) {                   // No restore possible, or the Backup Manager was mysteriously not                   // available -- just fire the post-install work request directly.                   if (DEBUG_INSTALL) Log.v(TAG, "No restore - queue post-install for " + token);                   Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0);                   mHandler.sendMessage(msg);               }           }       });   }

processPendingInstall()方法中post了一个消息，这样安装过程将以异步的方式继续执行。在post消息中，首先是调用installPackageLI()来装载应用，接下来的一大段代码是在执行设备备份操作，备份是通过BackupManagerService来完成的，这里就不分析了。备份完成之后，通过发送POST_INSTALL消息继续处理。

doPreInstall()一般情况下是什么都不会做的，接着看installPackageLI()方法，代码很长，所以依旧是以分段解析。

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private void installPackageLI(InstallArgs args, PackageInstalledInfo res) {        //得到installFlags，里面记录了app需要安装到哪里        final int installFlags = args.installFlags;        // 安装程序的包名        final String installerPackageName = args.installerPackageName;        // 与sd卡安装有关，一般为null        final String volumeUuid = args.volumeUuid;        // 前面已经把apk拷贝到了临时阶段性文件夹/data/app/vmdl<安装回话id>.tmp/这个目录了        final File tmpPackageFile = new File(args.getCodePath());        // 没有设定INSTALL_FORWARD_LOCK        final boolean forwardLocked = ((installFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0);        // 是否安装到外部存储        final boolean onExternal = (((installFlags & PackageManager.INSTALL_EXTERNAL) != 0)                || (args.volumeUuid != null));        // 初始化替换flag为假        boolean replace = false;        // 设置浏览参数        int scanFlags = SCAN_NEW_INSTALL | SCAN_UPDATE_SIGNATURE;        // 我们不是移动app，所以为null，不走这块代码        if (args.move != null) {            // moving a complete application; perfom an initial scan on the new install location            scanFlags |= SCAN_INITIAL;        }        // 初始化返回码        // Result object to be returned        res.returnCode = PackageManager.INSTALL_SUCCEEDED;

这里就是做了一些初始化值的工作。详情看上述注释。

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if (DEBUG_INSTALL) Slog.d(TAG, "installPackageLI: path=" + tmpPackageFile);      // Retrieve PackageSettings and parse package      // 设置解析apk的flags      final int parseFlags = mDefParseFlags | PackageParser.PARSE_CHATTY              | (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0)              | (onExternal ? PackageParser.PARSE_EXTERNAL_STORAGE : 0);      // 创建一个解析器      PackageParser pp = new PackageParser();      pp.setSeparateProcesses(mSeparateProcesses);      // 获得屏幕参数      pp.setDisplayMetrics(mMetrics);      final PackageParser.Package pkg;      try {          // 开始解析apk,要注意此时传入tmpPackageFile为一个文件夹          pkg = pp.parsePackage(tmpPackageFile, parseFlags);      } catch (PackageParserException e) {          res.setError("Failed parse during installPackageLI", e);          return;      }      // Mark that we have an install time CPU ABI override.      pkg.cpuAbiOverride = args.abiOverride;      String pkgName = res.name = pkg.packageName;      if ((pkg.applicationInfo.flags&ApplicationInfo.FLAG_TEST_ONLY) != 0) {          if ((installFlags & PackageManager.INSTALL_ALLOW_TEST) == 0) {              res.setError(INSTALL_FAILED_TEST_ONLY, "installPackageLI");              return;          }      }

这里主要是解析APK，也就是解析AndroidMainifest.xml文件，将结果记录在PackageParser.Package中。前面已经详细介绍如何解析一个APK了，所以这里不在赘述了。

接下来是搜集apk的签名信息，代码如下：

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try {            pp.collectCertificates(pkg, parseFlags);            pp.collectManifestDigest(pkg);        } catch (PackageParserException e) {            res.setError("Failed collect during installPackageLI", e);            return;        }

如果安装程序此前传入了一个清单文件，那么将解析到的清单文件与传入的进行对比。安装器的确传入了一个清单，PackageInstallerActivity中也解析了apk,那时记录了这个清单，并一并传入到这里了。这里又做了一步判断，判断两者是同一个apk.

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/* If the installer passed in a manifest digest, compare it now. */        if (args.manifestDigest != null) {            if (DEBUG_INSTALL) {                final String parsedManifest = pkg.manifestDigest == null ? "null"                        : pkg.manifestDigest.toString();                Slog.d(TAG, "Comparing manifests: " + args.manifestDigest.toString() + " vs. "                        + parsedManifest);            }            if (!args.manifestDigest.equals(pkg.manifestDigest)) {                res.setError(INSTALL_FAILED_PACKAGE_CHANGED, "Manifest digest changed");                return;            }        } else if (DEBUG_INSTALL) {            final String parsedManifest = pkg.manifestDigest == null                    ? "null" : pkg.manifestDigest.toString();            Slog.d(TAG, "manifestDigest was not present, but parser got: " + parsedManifest);        }

继续分析installPackageLI：

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// Check if installing already existing package            // 如果安装已经存在的应用的时候，PackageInstaller应用安装器会在会在installFlags中设置INSTALL_REPLACE_EXISTING           if ((installFlags & PackageManager.INSTALL_REPLACE_EXISTING) != 0) {                // 看看要替换的apk的包名是否存在原始包名                // 当app升级导致前后包名不一致的时候，需要记录仍然是原始包名，                // 所以这里要先检查要覆盖的app是否是这样的情况，是的话设置包名为旧的包名               String oldName = mSettings.mRenamedPackages.get(pkgName);               if (pkg.mOriginalPackages != null                       && pkg.mOriginalPackages.contains(oldName)                       && mPackages.containsKey(oldName)) {                   // This package is derived from an original package,                   // and this device has been updating from that original                   // name.  We must continue using the original name, so                   // rename the new package here.                   pkg.setPackageName(oldName);                   pkgName = pkg.packageName;                   replace = true;                   if (DEBUG_INSTALL) Slog.d(TAG, "Replacing existing renamed package: oldName="                           + oldName + " pkgName=" + pkgName);               } else if (mPackages.containsKey(pkgName)) {                   // This package, under its official name, already exists                   // on the device; we should replace it.                   replace = true;                   if (DEBUG_INSTALL) Slog.d(TAG, "Replace existing pacakge: " + pkgName);               }               // Prevent apps opting out from runtime permissions               // 检查新的app编译的时候选择的target目标版本低于6.0，而原来的app编译的时候target选择的是6.0，               // 当一个app按照6.0来编译的话，需要按照6.0的规则来解析app的权限。               if (replace) {                   PackageParser.Package oldPackage = mPackages.get(pkgName);                   final int oldTargetSdk = oldPackage.applicationInfo.targetSdkVersion;                   final int newTargetSdk = pkg.applicationInfo.targetSdkVersion;                   if (oldTargetSdk > Build.VERSION_CODES.LOLLIPOP_MR1                           && newTargetSdk <= Build.VERSION_CODES.LOLLIPOP_MR1) {                       res.setError(PackageManager.INSTALL_FAILED_PERMISSION_MODEL_DOWNGRADE,                               "Package " + pkg.packageName + " new target SDK " + newTargetSdk                                       + " doesn't support runtime permissions but the old"                                       + " target SDK " + oldTargetSdk + " does.");                       return;                   }               }           }           // 如果ps不为null,同样说明，已经存在一个同包名的程序被安装，           // 也就是还是处理覆盖安装的情况           // 这里主要是验证包名的签名，不一致的话，是不能覆盖安装的，另外版本号也不能比安装的低，否则也不能安装           PackageSetting ps = mSettings.mPackages.get(pkgName);          if (ps != null) {              if (DEBUG_INSTALL) Slog.d(TAG, "Existing package: " + ps);              // Quick sanity check that we're signed correctly if updating;              // we'll check this again later when scanning, but we want to              // bail early here before tripping over redefined permissions.              if (shouldCheckUpgradeKeySetLP(ps, scanFlags)) {                  if (!checkUpgradeKeySetLP(ps, pkg)) {                      res.setError(INSTALL_FAILED_UPDATE_INCOMPATIBLE, "Package "                              + pkg.packageName + " upgrade keys do not match the "                              + "previously installed version");                      return;                  }              } else {                  try {                      verifySignaturesLP(ps, pkg);                  } catch (PackageManagerException e) {                      res.setError(e.error, e.getMessage());                      return;                  }              }              oldCodePath = mSettings.mPackages.get(pkgName).codePathString;              if (ps.pkg != null && ps.pkg.applicationInfo != null) {                  systemApp = (ps.pkg.applicationInfo.flags &                          ApplicationInfo.FLAG_SYSTEM) != 0;              }              res.origUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true);          }

这里主要是对覆盖安装的时候，设置一些变量。

继续分析，接下来是对apk定义的权限进行初步检查：

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// Check whether the newly-scanned package wants to define an already-defined perm            int N = pkg.permissions.size();            for (int i = N-1; i >= 0; i--) {                PackageParser.Permission perm = pkg.permissions.get(i);                BasePermission bp = mSettings.mPermissions.get(perm.info.name);                if (bp != null) {                    // If the defining package is signed with our cert, it's okay.  This                    // also includes the "updating the same package" case, of course.                    // "updating same package" could also involve key-rotation.                    final boolean sigsOk;                    if (bp.sourcePackage.equals(pkg.packageName)                            && (bp.packageSetting instanceof PackageSetting)                            && (shouldCheckUpgradeKeySetLP((PackageSetting) bp.packageSetting,                                    scanFlags))) {                        sigsOk = checkUpgradeKeySetLP((PackageSetting) bp.packageSetting, pkg);                    } else {                        sigsOk = compareSignatures(bp.packageSetting.signatures.mSignatures,                                pkg.mSignatures) == PackageManager.SIGNATURE_MATCH;                    }                    if (!sigsOk) {                        // If the owning package is the system itself, we log but allow                        // install to proceed; we fail the install on all other permission                        // redefinitions.                        if (!bp.sourcePackage.equals("android")) {                            res.setError(INSTALL_FAILED_DUPLICATE_PERMISSION, "Package "                                    + pkg.packageName + " attempting to redeclare permission "                                    + perm.info.name + " already owned by " + bp.sourcePackage);                            res.origPermission = perm.info.name;                            res.origPackage = bp.sourcePackage;                            return;                        } else {                            Slog.w(TAG, "Package " + pkg.packageName                                    + " attempting to redeclare system permission "                                    + perm.info.name + "; ignoring new declaration");                            pkg.permissions.remove(i);                        }                    }                }            }

这段代码作用是检查apk中定义的所有的权限是否已经被其他应用定义了，如果重定义的是系统应用定义的权限，那么忽略本app定义的这个权限。如果重定义的是非系统应用的权限，那么本次安装就以失败返回。

继续分析，当一个app是系统应用，但又希望安装在外部存储，那么就报错。

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if (systemApp && onExternal) {            // Disable updates to system apps on sdcard            res.setError(INSTALL_FAILED_INVALID_INSTALL_LOCATION,                    "Cannot install updates to system apps on sdcard");            return;        }

意味着，系统app是不能安装到外部存储的。

继续分析：

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// 我们不是在移动app，所以不走这个分支if (args.move != null) {    // We did an in-place move, so dex is ready to roll    scanFlags |= SCAN_NO_DEX;    scanFlags |= SCAN_MOVE;    synchronized (mPackages) {        final PackageSetting ps = mSettings.mPackages.get(pkgName);        if (ps == null) {            res.setError(INSTALL_FAILED_INTERNAL_ERROR,                    "Missing settings for moved package " + pkgName);        }        // We moved the entire application as-is, so bring over the        // previously derived ABI information.        pkg.applicationInfo.primaryCpuAbi = ps.primaryCpuAbiString;        pkg.applicationInfo.secondaryCpuAbi = ps.secondaryCpuAbiString;    }} else if (!forwardLocked && !pkg.applicationInfo.isExternalAsec()) {  //走这个分支    // Enable SCAN_NO_DEX flag to skip dexopt at a later stage    // 设置SCAN_NO_DEX，这样在这个阶段就不会执行dexopt    scanFlags |= SCAN_NO_DEX;    try {        derivePackageAbi(pkg, new File(pkg.codePath), args.abiOverride,                true /* extract libs */);    } catch (PackageManagerException pme) {        Slog.e(TAG, "Error deriving application ABI", pme);        res.setError(INSTALL_FAILED_INTERNAL_ERROR, "Error deriving application ABI");        return;    }    // Run dexopt before old package gets removed, to minimize time when app is unavailable    int result = mPackageDexOptimizer            .performDexOpt(pkg, null /* instruction sets */, false /* forceDex */,                    false /* defer */, false /* inclDependencies */);    if (result == PackageDexOptimizer.DEX_OPT_FAILED) {        res.setError(INSTALL_FAILED_DEXOPT, "Dexopt failed for " + pkg.codePath);        return;    }}

derivePackageAbi()方法也很重要，主要完成了apk的so库路径设置，以及主次abi的值。

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/** * Derive the ABI of a non-system package located at {@code scanFile}. This information * is derived purely on the basis of the contents of {@code scanFile} and * {@code cpuAbiOverride}. * * If {@code extractLibs} is true, native libraries are extracted from the app if required. */public void derivePackageAbi(PackageParser.Package pkg, File scanFile,                             String cpuAbiOverride, boolean extractLibs)        throws PackageManagerException {    //这里是第一次调用，主要确定pkg中的applicationInfo中的下面三个字段    // nativeLibraryRootDir /data/app/vmdl<回话id>.tmp/lib    // nativeLibraryRootRequiresIsa 为true,用户安装的第三方app，该字段就为true,说明需要在lib/加前缀，如arm,arm64等    // nativeLibraryDir :/data/app/vmdl<回话id>.tmp/lib/<前缀>    setNativeLibraryPaths(pkg);    // We would never need to extract libs for forward-locked and external packages,    // since the container service will do it for us. We shouldn't attempt to    // extract libs from system app when it was not updated.    if (pkg.isForwardLocked() || isExternal(pkg) ||        (isSystemApp(pkg) && !pkg.isUpdatedSystemApp()) ) {        extractLibs = false;    }    final String nativeLibraryRootStr = pkg.applicationInfo.nativeLibraryRootDir;    // 对于用户安装的第三方app，该标志为true，预示着要在nativeLibraryRootStr路径后面加上“arm”或者”arm64"或者“x86”    // 这类的前缀，具体原因请参考setNativeLibraryPaths()    final boolean useIsaSpecificSubdirs = pkg.applicationInfo.nativeLibraryRootRequiresIsa;    NativeLibraryHelper.Handle handle = null;    try {        handle = NativeLibraryHelper.Handle.create(scanFile);        // TODO(multiArch): This can be null for apps that didn't go through the        // usual installation process. We can calculate it again, like we        // do during install time.        //        // TODO(multiArch): Why do we need to rescan ASEC apps again ? It seems totally        // unnecessary.        final File nativeLibraryRoot = new File(nativeLibraryRootStr);        // Null out the abis so that they can be recalculated.        pkg.applicationInfo.primaryCpuAbi = null;        pkg.applicationInfo.secondaryCpuAbi = null;        if (isMultiArch(pkg.applicationInfo)) {            // Warn if we've set an abiOverride for multi-lib packages..            // By definition, we need to copy both 32 and 64 bit libraries for            // such packages.            // cpuAbiOverride对于有多个so库文件夹的apk是无效的            if (pkg.cpuAbiOverride != null                    && !NativeLibraryHelper.CLEAR_ABI_OVERRIDE.equals(pkg.cpuAbiOverride)) {                Slog.w(TAG, "Ignoring abiOverride for multi arch application.");            }            int abi32 = PackageManager.NO_NATIVE_LIBRARIES;            int abi64 = PackageManager.NO_NATIVE_LIBRARIES;            if (Build.SUPPORTED_32_BIT_ABIS.length > 0) {                if (extractLibs) {                  // 这里再次拷贝，如果apk中的lib中的so库时间戳没有发生变化的时候，是不会在拷贝的，因为前面已经拷贝过了                  // 只有当so库发生变化的时候，才会再次拷贝                    abi32 = NativeLibraryHelper.copyNativeBinariesForSupportedAbi(handle,                            nativeLibraryRoot, Build.SUPPORTED_32_BIT_ABIS,                            useIsaSpecificSubdirs);                } else {                    abi32 = NativeLibraryHelper.findSupportedAbi(handle, Build.SUPPORTED_32_BIT_ABIS);                }            }            maybeThrowExceptionForMultiArchCopy(                    "Error unpackaging 32 bit native libs for multiarch app.", abi32);            if (Build.SUPPORTED_64_BIT_ABIS.length > 0) {                if (extractLibs) {                  // 这里再次拷贝，如果apk中的lib中的so库时间戳没有发生变化的时候，是不会在拷贝的，因为前面已经拷贝过了                  // 只有当so库发生变化的时候，才会再次拷贝                    abi64 = NativeLibraryHelper.copyNativeBinariesForSupportedAbi(handle,                            nativeLibraryRoot, Build.SUPPORTED_64_BIT_ABIS,                            useIsaSpecificSubdirs);                } else {                    abi64 = NativeLibraryHelper.findSupportedAbi(handle, Build.SUPPORTED_64_BIT_ABIS);                }            }            maybeThrowExceptionForMultiArchCopy(                    "Error unpackaging 64 bit native libs for multiarch app.", abi64);            if (abi64 >= 0) {                // 如果so库支持64位的abi,而且系统也是64位的话Message1                // 就把主abi设置为ro.product.cpu.abilist64列表中abi64索引的值                pkg.applicationInfo.primaryCpuAbi = Build.SUPPORTED_64_BIT_ABIS[abi64];            }            if (abi32 >= 0) {                final String abi = Build.SUPPORTED_32_BIT_ABIS[abi32];                if (abi64 >= 0) {                    // 当系统是64位。且apk中即包含了64位的库，又包含了32位的库，                    // 那么就把次abi设置为ro.product.cpu.abilist32列表中abi32索引的值                    pkg.applicationInfo.secondaryCpuAbi = abi;                } else {                    // 如果app只有32位的库，那么就把                    // 主abi设置为ro.product.cpu.abilist32列表中abi32索引的值                    pkg.applicationInfo.primaryCpuAbi = abi;                }            }        } else {           //对于apk中的lib中只有一个so库文件夹，走这个分支           // cpuAbiOverride传入的为null           // 所以abiList为ro.product.cpu.abilist列表中的值            String[] abiList = (cpuAbiOverride != null) ?                    new String[] { cpuAbiOverride } : Build.SUPPORTED_ABIS;            // Enable gross and lame hacks for apps that are built with old            // SDK tools. We must scan their APKs for renderscript bitcode and            // not launch them if it's present. Don't bother checking on devices            // that don't have 64 bit support.            boolean needsRenderScriptOverride = false;            if (Build.SUPPORTED_64_BIT_ABIS.length > 0 && cpuAbiOverride == null &&                    NativeLibraryHelper.hasRenderscriptBitcode(handle)) {                abiList = Build.SUPPORTED_32_BIT_ABIS;                needsRenderScriptOverride = true;            }            final int copyRet;            if (extractLibs) {               // 同样只有当so库发生变化时，才会再次拷贝                copyRet = NativeLibraryHelper.copyNativeBinariesForSupportedAbi(handle,                        nativeLibraryRoot, abiList, useIsaSpecificSubdirs);            } else {                copyRet = NativeLibraryHelper.findSupportedAbi(handle, abiList);            }            if (copyRet < 0 && copyRet != PackageManager.NO_NATIVE_LIBRARIES) {                throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR,                        "Error unpackaging native libs for app, errorCode=" + copyRet);            }            // 因为只有一个so库文件夹，所以只需要设置主abi即可            if (copyRet >= 0) {                pkg.applicationInfo.primaryCpuAbi = abiList[copyRet];            } else if (copyRet == PackageManager.NO_Message1NATIVE_LIBRARIES && cpuAbiOverride != null) {                pkg.applicationInfo.primaryCpuAbi = cpuAbiOverride;            } else if (needsRenderScriptOverride) {                pkg.Message1applicationInfo.primaryCpuAbi = abiList[0];            }        }    } catch (IOException ioe) {        Slog.e(TAG, "Unable to get canonical file " + ioe.toString());    } finally {        IoUtils.closeQuietly(handle);    }    // Now that we've calculated the ABIs and determined if it's an internal app,    // we will go ahead and populate the nativeLibraryPath.    // 再次执行该方法，设置pkg中的applicationInfo的字段    // secondaryNativeLibraryDir    setNativeLibraryPaths(pkg);}

接下来调用下面的代码进行了dexopt操作：

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// Run dexopt before old package gets removed, to minimize time when app is unavailableint result = mPackageDexOptimizer        .performDexOpt(pkg, null /* instruction sets */, false /* forceDex */,                false /* defer */, false /* inclDependencies */);if (result == PackageDexOptimizer.DEX_OPT_FAILED) {    res.setError(INSTALL_FAILED_DEXOPT, "Dexopt failed for " + pkg.codePath);    return;}

代码如下：

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int performDexOpt(PackageParser.Package pkg, String[] instructionSets,        boolean forceDex, boolean defer, boolean inclDependencies) {    ArraySet<String> done;    if (inclDependencies && (pkg.usesLibraries != null || pkg.usesOptionalLibraries != null)) {        done = new ArraySet<String>();        done.add(pkg.packageName);    } else {      // 走这个分支        done = null;    }    synchronized (mPackageManagerService.mInstallLock) {        final boolean useLock = mSystemReady;        if (useLock) {            mDexoptWakeLock.setWorkSource(new WorkSource(pkg.applicationInfo.uid));            mDexoptWakeLock.acquire();        }        try {            // -----------------调用下面的方法            return performDexOptLI(pkg, instructionSets, forceDex, defer, done);        } finally {            if (useLock) {                mDexoptWakeLock.release();            }        }    }}

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private int performDexOptLI(PackageParser.Package pkg, String[] targetInstructionSets,          boolean forceDex, boolean defer, ArraySet<String> done) {      //  传入的targetInstructionSets为null      //  所以instructionSets为前面设置pkg.applicationInfo的主次abi值      // 如果没有so库，也就没有设置主次abi,这时以ro.product.cpu.abilist列表第一个值，获取isa      final String[] instructionSets = targetInstructionSets != null ?              targetInstructionSets : getAppDexInstructionSets(pkg.applicationInfo);      // done 为null。所以跳过      if (done != null) {          done.add(pkg.packageName);          if (pkg.usesLibraries != null) {              performDexOptLibsLI(pkg.usesLibraries, instructionSets, forceDex, defer, done);          }          if (pkg.usesOptionalLibraries != null) {              performDexOptLibsLI(pkg.usesOptionalLibraries, instructionSets, forceDex, defer,                      done);          }      }      if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_HAS_CODE) == 0) {          return DEX_OPT_SKIPPED;      }      final boolean vmSafeMode = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_VM_SAFE_MODE) != 0;      final boolean debuggable = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0;      final List<String> paths = pkg.getAllCodePathsExcludingResourceOnly();      boolean performedDexOpt = false;      // There are three basic cases here:      // 1.) we need to dexopt, either because we are forced or it is needed      // 2.) we are deferring a needed dexopt      // 3.) we are skipping an unneeded dexopt      final String[] dexCodeInstructionSets = getDexCodeInstructionSets(instructionSets);      for (String dexCodeInstructionSet : dexCodeInstructionSets) {          if (!forceDex && pkg.mDexOptPerformed.contains(dexCodeInstructionSet)) {              continue;          }          for (String path : paths) {              final int dexoptNeeded;              if (forceDex) {                // 为false,所以不走这里                  dexoptNeeded = DexFile.DEX2OAT_NEEDED;              } else {                  try {                    // 因为是在安装apk，所以getDexOptNeeded返回的是DEX2OAT_NEEDED                      dexoptNeeded = DexFile.getDexOptNeeded(path, pkg.packageName,                              dexCodeInstructionSet, defer);                  } catch (IOException ioe) {                      Slog.w(TAG, "IOException reading apk: " + path, ioe);                      return DEX_OPT_FAILED;                  }              }              if (!forceDex && defer && dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {                  // We're deciding to defer a needed dexopt. Don't bother dexopting for other                  // paths and instruction sets. We'll deal with them all together when we process                  // our list of deferred dexopts.                  addPackageForDeferredDexopt(pkg);                  return DEX_OPT_DEFERRED;              }              if (dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {                  final String dexoptType;                  String oatDir = null;                  if (dexoptNeeded == DexFile.DEX2OAT_NEEDED) {                      dexoptType = "dex2oat";                      try {                        // 获取oat目录：/data/app/vmdl<安装回话id>.tmp/oat                          oatDir = createOatDirIfSupported(pkg, dexCodeInstructionSet);                      } catch (IOException ioe) {                          Slog.w(TAG, "Unable to create oatDir for package: " + pkg.packageName);                          return DEX_OPT_FAILED;                      }                  } else if (dexoptNeeded == DexFile.PATCHOAT_NEEDED) {                      dexoptType = "patchoat";                  } else if (dexoptNeeded == DexFile.SELF_PATCHOAT_NEEDED) {                      dexoptType = "self patchoat";                  } else {                      throw new IllegalStateException("Invalid dexopt needed: " + dexoptNeeded);                  }                  // 开始执行dex2oat                  Log.i(TAG, "Running dexopt (" + dexoptType + ") on: " + path + " pkg="                          + pkg.applicationInfo.packageName + " isa=" + dexCodeInstructionSet                          + " vmSafeMode=" + vmSafeMode + " debuggable=" + debuggable                          + " oatDir = " + oatDir);                  final int sharedGid = UserHandle.getSharedAppGid(pkg.applicationInfo.uid);                  final int ret = mPackageManagerService.mInstaller.dexopt(path, sharedGid,                          !pkg.isForwardLocked(), pkg.packageName, dexCodeInstructionSet,                          dexoptNeeded, vmSafeMode, debuggable, oatDir);                  // Dex2oat might fail due to compiler / verifier errors. We soldier on                  // regardless, and attempt to interpret the app as a safety net.                  if (ret == 0) {                      performedDexOpt = true;                  }              }          }              pkg.mDexOptPerformed.add(dexCodeInstructionSet);      }      return performedDexOpt ? DEX_OPT_PERFORMED : DEX_OPT_SKIPPED;  }

这里执行dexopt实际上是在执行dex2oat，用来将apk中的dex文件转换为oat文件。值得注意的是，Android 6.0之前生成的oat文件都在

1

/data/dalvik_cache/

文件夹中，从Android 6.0 开始这个文件夹中只存放系统内置应用的oat文件，用户安装的app的oat文件在，最终会在

1

/data/app/包名/oat/<isa>/

继续分析installPackageLI：

1234

if (!args.doRename(res.returnCode, pkg, oldCodePath)) {            res.setError(INSTALL_FAILED_INSUFFICIENT_STORAGE, "Failed rename");            return;        }

这段代码作用从名字上就很清楚了:重命名。就是将

1

/data/app/vmdl<安装会话id>.tmp

重名为

1

/data/app/包名-suffix

suffix为1,2…….

同时更新pkg中的受影响的字段。

继续分析installPackageLI：

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startIntentFilterVerifications(args.user.getIdentifier(), replace, pkg);      if (replace) {        // 如果是覆盖安装，则走这里          replacePackageLI(pkg, parseFlags, scanFlags | SCAN_REPLACING, args.user,                  installerPackageName, volumeUuid, res);      } else {        // 初次安装，走这里          installNewPackageLI(pkg, parseFlags, scanFlags | SCAN_DELETE_DATA_ON_FAILURES,                  args.user, installerPackageName, volumeUuid, res);      }      synchronized (mPackages) {          final PackageSetting ps = mSettings.mPackages.get(pkgName);          if (ps != null) {              res.newUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true);          }      }

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private void installNewPackageLI(PackageParser.Package pkg, int parseFlags, int scanFlags,        UserHandle user, String installerPackageName, String volumeUuid,        PackageInstalledInfo res) {    // Remember this for later, in case we need to rollback this install    String pkgName = pkg.packageName;    if (DEBUG_INSTALL) Slog.d(TAG, "installNewPackageLI: " + pkg);    final boolean dataDirExists = Environment            .getDataUserPackageDirectory(volumeUuid, UserHandle.USER_OWNER, pkgName).exists();    synchronized(mPackages) {        // 判断是否构成升级关系        if (mSettings.mRenamedPackages.containsKey(pkgName)) {            res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName                    + " without first uninstalling package running as "                    + mSettings.mRenamedPackages.get(pkgName));            return;        }        // 看是否已经安装了        if (mPackages.containsKey(pkgName)) {            // Don't allow installation over an existing package with the same name.            res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName                    + " without first uninstalling.");            return;        }    }    try {      // 很熟悉了吧，这里又调用了scanPackageLI        PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags, scanFlags,                System.currentTimeMillis(), user);        updateSettingsLI(newPackage, installerPackageName, volumeUuid, null, null, res, user);        if (res.returnCode != PackageManager.INSTALL_SUCCEEDED) {            deletePackageLI(pkgName, UserHandle.ALL, false, null, null,                    dataDirExists ? PackageManager.DELETE_KEEP_DATA : 0,                            res.removedInfo, true);        }    } catch (PackageManagerException e) {        res.setError("Package couldn't be installed in " + pkg.codePath, e);    }}

重点又回到了scanPackageLI参数为Package的方法了。该方法内部又调用scanPackageDirtyLI方法,前面文章详细讲解过了，这里值贴出与用户安装app相关的代码

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private PackageParser.Package scanPackageDirtyLI(PackageParser.Package pkg, int parseFlags,            int scanFlags, long currentTime, UserHandle user) throws PackageManagerException {        final File scanFile = new File(pkg.codePath);         ........................        if ((parseFlags&PackageParser.PARSE_IS_SYSTEM) != 0) {            pkg.applicationInfo.flags |= ApplicationInfo.FLAG_SYSTEM;        } else {            // Only allow system apps to be flagged as core apps.            pkg.coreApp = false;        }       .........................................        // Initialize package source and resource directories        File destCodeFile = new File(pkg.applicationInfo.getCodePath());        File destResourceFile = new File(pkg.applicationInfo.getResourcePath());        SharedUserSetting suid = null;        PackageSetting pkgSetting = null;        .............................................        // writer        synchronized (mPackages) {            if (pkg.mSharedUserId != null) {              .................................            }            // Check if we are renaming from an original package name.            PackageSetting origPackage = null;            String realName = null;            if (pkg.mOriginalPackages != null) {              ...............................            }            ..................................            // 很重要，在这个方法里面，给该apk分配了UID            // 并且将一些信息记录当前用户的包状态文件：            // /data/system/users/userid/package-restrictions.xml            // 不如当前app是否被隐藏，或者禁用，以及当前app哪些组件被禁用等。            pkgSetting = mSettings.getPackageLPw(pkg, origPackage, realName, suid, destCodeFile,                    destResourceFile, pkg.applicationInfo.nativeLibraryRootDir,                    pkg.applicationInfo.primaryCpuAbi,                    pkg.applicationInfo.secondaryCpuAbi,                    pkg.applicationInfo.flags, pkg.applicationInfo.privateFlags,                    user, false);            if (pkgSetting == null) {                throw new PackageManagerException(INSTALL_FAILED_INSUFFICIENT_STORAGE,                        "Creating application package " + pkg.packageName + " failed");            }          .................................            pkg.applicationInfo.uid = pkgSetting.appId;            pkg.mExtras = pkgSetting;          .....................................        //检查安装的app与已经安装的app定义的组件是否冲突            if ((scanFlags & SCAN_NEW_INSTALL) != 0) {                final int N = pkg.providers.size();                int i;                for (i=0; i<N; i++) {                    PackageParser.Provider p = pkg.providers.get(i);                    ...................................                    }                }            }            ....................................        final String pkgName = pkg.packageName;        final long scanFileTime = scanFile.lastModified();        final boolean forceDex = (scanFlags & SCAN_FORCE_DEX) != 0;        //修改进程信息，如名字等        pkg.applicationInfo.processName = fixProcessName(                pkg.applicationInfo.packageName,                pkg.applicationInfo.processName,                pkg.applicationInfo.uid);        File dataPath;        if (mPlatformPackage == pkg) {          ....................................        } else {            // 开始创建数据沙箱目录            dataPath = Environment.getDataUserPackageDirectory(pkg.volumeUuid,                    UserHandle.USER_OWNER, pkg.packageName);            boolean uidError = false;            if (dataPath.exists()) {              ..........................................            } else {              ...............              // 调用守护进程installd来完成实际的创建工作              // installd的install会创建"/data/data/包名",权限751，默认是给userid为0的用户使用              // 其内部会调用installd的createUserData为每一个非0的系统用户都创建沙箱目录              // /data/user/userid/包名 ，并设置权限751，chown设置为该用户的属主                int ret = createDataDirsLI(pkg.volumeUuid, pkgName, pkg.applicationInfo.uid,                        pkg.applicationInfo.seinfo);                if (ret < 0) {                    // Error from installer                    throw new PackageManagerException(INSTALL_FAILED_INSUFFICIENT_STORAGE,                            "Unable to create data dirs [errorCode=" + ret + "]");                }              ............................................        }        final String path = scanFile.getPath();        final String cpuAbiOverride = deriveAbiOverride(pkg.cpuAbiOverride, pkgSetting);        if ((scanFlags & SCAN_NEW_INSTALL) == 0) {          ..........................................        } else {            if ((scanFlags & SCAN_MOVE) != 0) {              .....................................            }      .........................        }        // 开始创建so库文件的连接        if (DEBUG_INSTALL) Slog.i(TAG, "Linking native library dir for " + path);//========================================        final int[] userIds = sUserManager.getUserIds();        synchronized (mInstallLock) {          ................................            //只有设置了主abi,且主abi的so库是32位的才进行软连接            if (pkg.applicationInfo.primaryCpuAbi != null &&                    !VMRuntime.is64BitAbi(pkg.applicationInfo.primaryCpuAbi)) {                final String nativeLibPath = pkg.applicationInfo.nativeLibraryDir;                for (int userId : userIds) {                  // 对该app在所有用户中的沙箱目录中创建lib指向/data/app/包名-suffix/lib/<isa>/的软连接                    if (mInstaller.linkNativeLibraryDirectory(pkg.volumeUuid, pkg.packageName,                            nativeLibPath, userId) < 0) {                        throw new PackageManagerException(INSTALL_FAILED_INTERNAL_ERROR,                                "Failed linking native library dir (user=" + userId + ")");                    }                }            }        }        pkgSetting.primaryCpuAbiString = pkg.applicationInfo.primaryCpuAbi;        pkgSetting.secondaryCpuAbiString = pkg.applicationInfo.secondaryCpuAbi;        pkgSetting.cpuAbiOverrideString = cpuAbiOverride;        ...........................        pkgSetting.legacyNativeLibraryPathString = pkg.applicationInfo.nativeLibraryRootDir;      ..........................................      // 将安装该apk是产生的PackageSetting对象pkgSetting，加入mSettings中的mPackages，以及也加入到PMS中的mPackages        // writer        synchronized (mPackages) {            // Add the new setting to mSettings            mSettings.insertPackageSettingLPw(pkgSetting, pkg);            // Add the new setting to mPackages            mPackages.put(pkg.applicationInfo.packageName, pkg);            // Add the package's KeySets to the global KeySetManagerService            ksms.addScannedPackageLPw(pkg);            int N = pkg.providers.size();            StringBuilder r = null;            int i;            // 将安装的apk中的内容提供者加入到PMS中的mProviders            for (i=0; i<N; i++) {              ...................                mProviders.addProvider(p);            ..........................            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Providers: " + r);            }            N = pkg.services.size();            r = null;              // 将安装的apk中的service加入到PMS中的mServices            for (i=0; i<N; i++) {            .......................                mServices.addService(s);            ......................            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Services: " + r);            }          // 将安装的apk中的receivers加入到PMS中的mReceivers            N = pkg.receivers.size();            r = null;            for (i=0; i<N; i++) {            .....................                mReceivers.addActivity(a, "receiver");          ............            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Receivers: " + r);            }            N = pkg.activities.size();            r = null;        // 将安装的apk中的activity加入到PMS中的mActivities            for (i=0; i<N; i++) {            ....................................                mActivities.addActivity(a, "activity");            .............................            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Activities: " + r);            }            N = pkg.permissionGroups.size();            r = null;            for (i=0; i<N; i++) {                PackageParser.PermissionGroup pg = pkg.permissionGroups.get(i);                PackageParser.PermissionGroup cur = mPermissionGroups.get(pg.info.name);                if (cur == null) {                    mPermissionGroups.put(pg.info.name, pg);                .........................                } else {                .............................                }            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Permission Groups: " + r);            }            N = pkg.permissions.size();            r = null;            for (i=0; i<N; i++) {                ....................................                if (pkg.applicationInfo.targetSdkVersion > Build.VERSION_CODES.LOLLIPOP_MR1) {                    p.group = mPermissionGroups.get(p.info.group);                .....................................                }              ....................                if (bp == null) {                    bp = new BasePermission(p.info.name, p.info.packageName,                            BasePermission.TYPE_NORMAL);                    permissionMap.put(p.info.name, bp);                }          ................................          //设置instrumentation            N = pkg.instrumentation.size();            r = null;            for (i=0; i<N; i++) {                PackageParser.Instrumentation a = pkg.instrumentation.get(i);                a.info.packageName = pkg.applicationInfo.packageName;              .................................            }            if (r != null) {                if (DEBUG_PACKAGE_SCANNING) Log.d(TAG, "  Instrumentation: " + r);            }            if (pkg.protectedBroadcasts != null) {                N = pkg.protectedBroadcasts.size();                for (i=0; i<N; i++) {                    mProtectedBroadcasts.add(pkg.protectedBroadcasts.get(i));                }            }            pkgSetting.setTimeStamp(scanFileTime);            ..............................        return pkg;    }

从installPackageLI的重要执行过程如下图所示：

执行完installPackageLI之后，返回processPendingInstall方法中，如下所示：

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private void processPendingInstall(final InstallArgs args, final int currentStatus) {       // Queue up an async operation since the package installation may take a little while.       mHandler.post(new Runnable() {           public void run() {            ...........................               if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {                    //一般情况下，什么都不会做的                   args.doPreInstall(res.returnCode);                   synchronized (mInstallLock) {                       installPackageLI(args, res);                   }                   // 安装失败时，删除/data/app/包名中的内容                   args.doPostInstall(res.returnCode, res.uid);               }            .....................................            /* 省略关于云备份的代码*/            .....................................               if (!doRestore) {                   // No restore possible, or the Backup Manager was mysteriously not                   // available -- just fire the post-install work request directly.                   if (DEBUG_INSTALL) Log.v(TAG, "No restore - queue post-install for " + token);                   Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0);                   mHandler.sendMessage(msg);               }           }       });   }

接下来就是发送POST_INSTALL消息，该消息的处理主要就是在发送广播，应用安装完成之后要通知系统中的其他应用开始处理，比如在launcher需要增加app的图标等。等发完广播，安装也就结束了，最后通过最初安装是传入的安装观察者observer返回最初的调用者。

发送的广播有

1. android.intent.action.PACKAGE_ADDED

2. 覆盖安装时，还要发送:android.intent.extra.REPLACING

代码如下：

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sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED,        packageName, extras, null, null, firstUsers);final boolean update = res.removedInfo.removedPackage != null;if (update) {    extras.putBoolean(Intent.EXTRA_REPLACING, true);}sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED,        packageName, extras, null, null, updateUsers);if (update) {    sendPackageBroadcast(Intent.ACTION_PACKAGE_REPLACED,            packageName, extras, null, null, updateUsers);    sendPackageBroadcast(Intent.ACTION_MY_PACKAGE_REPLACED,            null, null, packageName, null, updateUsers);    ................