最后把上面两者mAppIds和mOtherUserIds所有SharedUserSetting放到别外一个容器里mSharedUsers，通过一个name作为它们的key，来找到具体的SharedUserSetting

这个机制用处：

• 同一种 sharedUserId的不同的App 可共享彼此的数据且也可运行在同一进程中。

• 通过在清单文件中指定对应的 sharedUserId，可以使得 App 所在进程将被赋予指定的 UID。例如在应用清单里配置了android:sharedUserId="android.uid.system"属性，如果该App的签名也是使用platform级别的签名证书（即在其 Android.mk 中需要额外声明 LOCAL_CERTIFICATE := platform）时，相当于是把该进程的UID设置为system的UID，也就拥有了系统权限。

Settings.readLPw

boolean readLPw(@NonNull List users) {...// 解析"/data/system/packages.xml"final TypedXmlPullParser parser = Xml.resolvePullParser(str);int type;while ((type = parser.next()) != XmlPullParser.START_TAG&& type != XmlPullParser.END_DOCUMENT) {;}if (type != XmlPullParser.START_TAG) {mReadMessages.append("No start tag found in settings file\n");PackageManagerService.reportSettingsProblem(Log.WARN,"No start tag found in package manager settings");Slog.wtf(PackageManagerService.TAG,"No start tag found in package manager settings");return false;}int outerDepth = parser.getDepth();while ((type = parser.next()) != XmlPullParser.END_DOCUMENT&& (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) {continue;}// 对各个标签进行解析,建立对应的数据结构String tagName = parser.getName();if (tagName.equals("package")) {readPackageLPw(parser, users);} else if (tagName.equals("permissions")) {mPermissions.readPermissions(parser);} else if (tagName.equals("permission-trees")) {mPermissions.readPermissionTrees(parser);} else if (tagName.equals("shared-user")) {readSharedUserLPw(parser, users);} ....}}str.close();} catch (IOException | XmlPullParserException e) {mReadMessages.append("Error reading: " + e.toString());PackageManagerService.reportSettingsProblem(Log.ERROR, "Error reading settings: " + e);Slog.wtf(PackageManagerService.TAG, "Error reading package manager settings", e);}....}

小结

• 初始化一些屏幕信息DisplayMestrics，与应用相关的Installer，多用户管理UserManager等
• 初始化保存系统包信息的Settings,并将一些重要的uid，比如system,phone添加进去
• 初始化SystemConfig去读取某些目录下配置，权限，so库

**阶段2：**BOOT_PROGRESS_PMS_SYSTEM_SCAN_START

android-12.0.0_r28\frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

			long startTime = SystemClock.uptimeMillis();EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_SYSTEM_SCAN_START,startTime);// 两个系统环境变量final String bootClassPath = System.getenv("BOOTCLASSPATH");final String systemServerClassPath = System.getenv("SYSTEMSERVERCLASSPATH");if (bootClassPath == null) {Slog.w(TAG, "No BOOTCLASSPATH found!");}if (systemServerClassPath == null) {Slog.w(TAG, "No SYSTEMSERVERCLASSPATH found!");}// 目录 /system/frameworkFile frameworkDir = new File(Environment.getRootDirectory(), "framework");// 获取内部版本号final VersionInfo ver = mSettings.getInternalVersion();// 通过fingerprint是否有更新mIsUpgrade =!buildFingerprint.equals(ver.fingerprint);if (mIsUpgrade) {PackageManagerServiceUtils.logCriticalInfo(Log.INFO,"Upgrading from " + ver.fingerprint + " to " + Build.FINGERPRINT);}// when upgrading from pre-M, promote system app permissions from install to runtime// 当是从Android M版本升级上来，要将系统应用的安装权限变成运行时权限mPromoteSystemApps =mIsUpgrade && ver.sdkVersion <= Build.VERSION_CODES.LOLLIPOP_MR1;// When upgrading from pre-N, we need to handle package extraction like first boot,// as there is no profiling data available.// 当是从Android N版本升级上来，需像首次启动一样处理包mIsPreNUpgrade = mIsUpgrade && ver.sdkVersion < Build.VERSION_CODES.N;mIsPreNMR1Upgrade = mIsUpgrade && ver.sdkVersion < Build.VERSION_CODES.N_MR1;mIsPreQUpgrade = mIsUpgrade && ver.sdkVersion < Build.VERSION_CODES.Q;final WatchedArrayMap packageSettings =mSettings.getPackagesLocked();// Save the names of pre-existing packages prior to scanning, so we can determine// which system packages are completely new due to an upgrade.// 在扫描之前保存现有包的名称，以便我们可以确定哪些系统包是由于升级而全新的。if (isDeviceUpgrading()) {mExistingPackages = new ArraySet<>(packageSettings.size());for (PackageSetting ps : packageSettings.values()) {mExistingPackages.add(ps.name);}}// 目录/data/system/package_cachemCacheDir = preparePackageParserCache(mIsEngBuild);// Set flag to monitor and not change apk file paths when// scanning install directories.int scanFlags = SCAN_BOOTING | SCAN_INITIAL;if (mIsUpgrade || mFirstBoot) {scanFlags = scanFlags | SCAN_FIRST_BOOT_OR_UPGRADE;}final int systemParseFlags = mDefParseFlags | ParsingPackageUtils.PARSE_IS_SYSTEM_DIR;final int systemScanFlags = scanFlags | SCAN_AS_SYSTEM;// 创建 PackageParser2 对象 packageParser，后续用来解析各种 apk 文件PackageParser2 packageParser = injector.getScanningCachingPackageParser();// packageParser 解析用的线程池ExecutorService executorService = ParallelPackageParser.makeExecutorService();// Prepare apex package info before scanning APKs, these information are needed when// scanning apk in apex.// 在扫描 APK 之前，准备好 apex 包信息，在以下情况下需要扫描apk时需要这些信息mApexManager.scanApexPackagesTraced(packageParser, executorService);// Collect vendor/product/system_ext overlay packages. (Do this before scanning// any apps.)// For security and version matching reason, only consider overlay packages if they// reside in the right directory.for (int i = mDirsToScanAsSystem.size() - 1; i >= 0; i--) {final ScanPartition partition = mDirsToScanAsSystem.get(i);if (partition.getOverlayFolder() == null) {continue;}// mDirsToScanAsSystem是阶段1的时候声明的，里面就是/system/app，/system/priv-app，/system/overlay等目录// 解析DirsToScanAsSystem的overlay目录目录所有apk等信息，耗时操作scanDirTracedLI(partition.getOverlayFolder(), systemParseFlags,systemScanFlags | partition.scanFlag, 0,packageParser, executorService);}// 扫描 /system/framework 目录scanDirTracedLI(frameworkDir, systemParseFlags,systemScanFlags | SCAN_NO_DEX | SCAN_AS_PRIVILEGED, 0,packageParser, executorService);if (!mPackages.containsKey("android")) {throw new IllegalStateException("Failed to load frameworks package; check log for warnings");}// 开始扫描各个目录for (int i = 0, size = mDirsToScanAsSystem.size(); i < size; i++) {final ScanPartition partition = mDirsToScanAsSystem.get(i);if (partition.getPrivAppFolder() != null) {//解析DirsToScanAsSystem的priv-app目录目录所有apk等信息，耗时操作scanDirTracedLI(partition.getPrivAppFolder(), systemParseFlags,systemScanFlags | SCAN_AS_PRIVILEGED | partition.scanFlag, 0,packageParser, executorService);}//解析DirsToScanAsSystem的app目录目录所有apk等信息，耗时操作scanDirTracedLI(partition.getAppFolder(), systemParseFlags,systemScanFlags | partition.scanFlag, 0,packageParser, executorService);}// Parse overlay configuration files to set default enable state, mutability, and// priority of system overlays.// 解析overlay配置文件以设置系统覆盖的默认启用状态、可变性和优先级。mOverlayConfig = OverlayConfig.initializeSystemInstance(consumer -> mPmInternal.forEachPackage(pkg -> consumer.accept(pkg, pkg.isSystem())));// Prune any system packages that no longer exist.// 收集可能不再存在的系统Appfinal List possiblyDeletedUpdatedSystemApps = new ArrayList<>();// Stub packages must either be replaced with full versions in the /data// partition or be disabled.final List stubSystemApps = new ArrayList<>();final int[] userIds = mUserManager.getUserIds();// 如果不是只加载核心apk，一般情况都是falseif (!mOnlyCore) {// do this first before mucking with mPackages for the "expecting better" casefinal int numPackages = mPackages.size();for (int index = 0; index < numPackages; index++) {final AndroidPackage pkg = mPackages.valueAt(index);if (pkg.isStub()) {stubSystemApps.add(pkg.getPackageName());}}// Iterates PackageSettings in reversed order because the item could be removed// during the iteration.for (int index = packageSettings.size() - 1; index >= 0; index--) {final PackageSetting ps = packageSettings.valueAt(index);/** If this is not a system app, it can't be a* disable system app.*/if ((ps.pkgFlags & ApplicationInfo.FLAG_SYSTEM) == 0) {continue;}/** If the package is scanned, it's not erased.*/final AndroidPackage scannedPkg = mPackages.get(ps.name);if (scannedPkg != null) {/** If the system app is both scanned and in the* disabled packages list, then it must have been* added via OTA. Remove it from the currently* scanned package so the previously user-installed* application can be scanned.*/if (mSettings.isDisabledSystemPackageLPr(ps.name)) {logCriticalInfo(Log.WARN,"Expecting better updated system app for " + ps.name+ "; removing system app.  Last known"+ " codePath=" + ps.getPathString()+ ", versionCode=" + ps.versionCode+ "; scanned versionCode=" + scannedPkg.getLongVersionCode());removePackageLI(scannedPkg, true);mExpectingBetter.put(ps.name, ps.getPath());}continue;}if (!mSettings.isDisabledSystemPackageLPr(ps.name)) {logCriticalInfo(Log.WARN, "System package " + ps.name+ " no longer exists; it's data will be wiped");removePackageDataLIF(ps, userIds, null, 0, false);} else {// we still have a disabled system package, but, it still might have// been removed. check the code path still exists and check there's// still a package. the latter can happen if an OTA keeps the same// code path, but, changes the package name.final PackageSetting disabledPs =mSettings.getDisabledSystemPkgLPr(ps.name);if (disabledPs.getPath() == null || !disabledPs.getPath().exists()|| disabledPs.pkg == null) {possiblyDeletedUpdatedSystemApps.add(ps.name);} else {// We're expecting that the system app should remain disabled, but add// it to expecting better to recover in case the data version cannot// be scanned.mExpectingBetter.put(disabledPs.name, disabledPs.getPath());}}}}final int cachedSystemApps = PackageCacher.sCachedPackageReadCount.get();// Remove any shared userIDs that have no associated packagesmSettings.pruneSharedUsersLPw();final long systemScanTime = SystemClock.uptimeMillis() - startTime;final int systemPackagesCount = mPackages.size();Slog.i(TAG, "Finished scanning system apps. Time: " + systemScanTime+ " ms, packageCount: " + systemPackagesCount+ " , timePerPackage: "+ (systemPackagesCount == 0 ? 0 : systemScanTime / systemPackagesCount)+ " , cached: " + cachedSystemApps);if (mIsUpgrade && systemPackagesCount > 0) {//CHECKSTYLE:OFF IndentationCheckFrameworkStatsLog.write(FrameworkStatsLog.BOOT_TIME_EVENT_DURATION_REPORTED,BOOT_TIME_EVENT_DURATION__EVENT__OTA_PACKAGE_MANAGER_SYSTEM_APP_AVG_SCAN_TIME,systemScanTime / systemPackagesCount);//CHECKSTYLE:ON IndentationCheck}

小结

• 对于旧版本升级的情况，将安装时获取权限变更为运行时申请权限；

• 扫描system/vendor/product/odm/oem等目录的priv-app、app、overlay包-

• 清除安装时临时文件以及其他不必要的信息。

**阶段3：**BOOT_PROGRESS_PMS_DATA_SCAN_START

android-12.0.0_r28\frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

 			// 如果不是只加载核心apk，一般情况都是falseif (!mOnlyCore) {EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START,SystemClock.uptimeMillis());// 在/data/app目录扫描用户安装文件，mAppInstallDir 目录是在阶段1中创建的scanDirTracedLI(mAppInstallDir, 0, scanFlags | SCAN_REQUIRE_KNOWN, 0,packageParser, executorService);}packageParser.close();List unfinishedTasks = executorService.shutdownNow();if (!unfinishedTasks.isEmpty()) {throw new IllegalStateException("Not all tasks finished before calling close: "+ unfinishedTasks);}if (!mOnlyCore) {// Remove disable package settings for updated system apps that were// removed via an OTA. If the update is no longer present, remove the// app completely. Otherwise, revoke their system privileges.// 删除已通过OTA删除的更新系统应用程序的禁用包设置。如果更新不再存在，则完全删除应用程序。否则，取消其系统权限。for (int i = possiblyDeletedUpdatedSystemApps.size() - 1; i >= 0; --i) {final String packageName = possiblyDeletedUpdatedSystemApps.get(i);final AndroidPackage pkg = mPackages.get(packageName);final String msg;// remove from the disabled system list; do this first so any future// scans of this package are performed without this state// 从禁用的系统列表中删除mSettings.removeDisabledSystemPackageLPw(packageName);if (pkg == null) {// should have found an update, but, we didn't; remove everythingmsg = "Updated system package " + packageName+ " no longer exists; removing its data";// Actual deletion of code and data will be handled by later// reconciliation step} else {// found an update; revoke system privilegesmsg = "Updated system package " + packageName+ " no longer exists; rescanning package on data";// NOTE: We don't do anything special if a stub is removed from the// system image. But, if we were [like removing the uncompressed// version from the /data partition], this is where it'd be done.// remove the package from the system and re-scan it without any// special privileges// 从系统中删除该包并重新扫描权限removePackageLI(pkg, true);try {final File codePath = new File(pkg.getPath());scanPackageTracedLI(codePath, 0, scanFlags, 0, null);} catch (PackageManagerException e) {Slog.e(TAG, "Failed to parse updated, ex-system package: "+ e.getMessage());}}// one final check. if we still have a package setting [ie. it was// previously scanned and known to the system], but, we don't have// a package [ie. there was an error scanning it from the /data// partition], completely remove the package data.final PackageSetting ps = mSettings.getPackageLPr(packageName);if (ps != null && mPackages.get(packageName) == null) {removePackageDataLIF(ps, userIds, null, 0, false);}logCriticalInfo(Log.WARN, msg);}/** Make sure all system apps that we expected to appear on* the userdata partition actually showed up. If they never* appeared, crawl back and revive the system version.*/// 确保所有期望在用户数据分区上的系统应用程序都能出现。// 如果没有出现就回滚系统版本for (int i = 0; i < mExpectingBetter.size(); i++) {final String packageName = mExpectingBetter.keyAt(i);if (!mPackages.containsKey(packageName)) {final File scanFile = mExpectingBetter.valueAt(i);logCriticalInfo(Log.WARN, "Expected better " + packageName+ " but never showed up; reverting to system");@ParseFlags int reparseFlags = 0;@ScanFlags int rescanFlags = 0;for (int i1 = mDirsToScanAsSystem.size() - 1; i1 >= 0; i1--) {final ScanPartition partition = mDirsToScanAsSystem.get(i1);if (partition.containsPrivApp(scanFile)) {reparseFlags = systemParseFlags;rescanFlags = systemScanFlags | SCAN_AS_PRIVILEGED| partition.scanFlag;break;}if (partition.containsApp(scanFile)) {reparseFlags = systemParseFlags;rescanFlags = systemScanFlags | partition.scanFlag;break;}}if (rescanFlags == 0) {Slog.e(TAG, "Ignoring unexpected fallback path " + scanFile);continue;}mSettings.enableSystemPackageLPw(packageName);try {final AndroidPackage newPkg = scanPackageTracedLI(scanFile, reparseFlags, rescanFlags, 0, null);// We rescanned a stub, add it to the list of stubbed system packagesif (newPkg.isStub()) {stubSystemApps.add(packageName);}} catch (PackageManagerException e) {Slog.e(TAG, "Failed to parse original system package: "+ e.getMessage());}}}// Uncompress and install any stubbed system applications.// This must be done last to ensure all stubs are replaced or disabled.// 解压并安装任何存根的系统应用程序。// 必须最后进行，以确保所有存根被替换或禁用。installSystemStubPackages(stubSystemApps, scanFlags);final int cachedNonSystemApps = PackageCacher.sCachedPackageReadCount.get()- cachedSystemApps;final long dataScanTime = SystemClock.uptimeMillis() - systemScanTime - startTime;final int dataPackagesCount = mPackages.size() - systemPackagesCount;Slog.i(TAG, "Finished scanning non-system apps. Time: " + dataScanTime+ " ms, packageCount: " + dataPackagesCount+ " , timePerPackage: "+ (dataPackagesCount == 0 ? 0 : dataScanTime / dataPackagesCount)+ " , cached: " + cachedNonSystemApps);if (mIsUpgrade && dataPackagesCount > 0) {//CHECKSTYLE:OFF IndentationCheckFrameworkStatsLog.write(FrameworkStatsLog.BOOT_TIME_EVENT_DURATION_REPORTED,BOOT_TIME_EVENT_DURATION__EVENT__OTA_PACKAGE_MANAGER_DATA_APP_AVG_SCAN_TIME,dataScanTime / dataPackagesCount);//CHECKSTYLE:OFF IndentationCheck}}mExpectingBetter.clear();// Resolve the storage manager.mStorageManagerPackage = getStorageManagerPackageName();// Resolve protected action filters. Only the setup wizard is allowed to// have a high priority filter for these actions.mSetupWizardPackage = getSetupWizardPackageNameImpl();mComponentResolver.fixProtectedFilterPriorities();mDefaultTextClassifierPackage = getDefaultTextClassifierPackageName();mSystemTextClassifierPackageName = getSystemTextClassifierPackageName();mDocumenterPackage = getDocumenterPackageName();mConfiguratorPackage = getDeviceConfiguratorPackageName();mAppPredictionServicePackage = getAppPredictionServicePackageName();mIncidentReportApproverPackage = getIncidentReportApproverPackageName();mRetailDemoPackage = getRetailDemoPackageName();mOverlayConfigSignaturePackage = getOverlayConfigSignaturePackageName();mRecentsPackage = getRecentsPackageName();// Now that we know all of the shared libraries, update all clients to have// the correct library paths.// 现在解析完了所有的共享库，更新到所有的客户端，// 以保证它拥有正确的库路径。updateAllSharedLibrariesLocked(null, null, Collections.unmodifiableMap(mPackages));for (SharedUserSetting setting : mSettings.getAllSharedUsersLPw()) {// NOTE: We ignore potential failures here during a system scan (like// the rest of the commands above) because there's precious little we// can do about it. A settings error is reported, though.final List changedAbiCodePath =applyAdjustedAbiToSharedUser(setting, null /*scannedPackage*/,mInjector.getAbiHelper().getAdjustedAbiForSharedUser(setting.packages, null /*scannedPackage*/));if (changedAbiCodePath != null && changedAbiCodePath.size() > 0) {for (int i = changedAbiCodePath.size() - 1; i >= 0; --i) {final String codePathString = changedAbiCodePath.get(i);try {mInstaller.rmdex(codePathString,getDexCodeInstructionSet(getPreferredInstructionSet()));} catch (InstallerException ignored) {}}}// Adjust seInfo to ensure apps which share a sharedUserId are placed in the same// SELinux domain.// 调整seInfo以确保共享UserId的应用程序被放置在同一个// SELinux域。setting.fixSeInfoLocked();setting.updateProcesses();}// Now that we know all the packages we are keeping,// read and update their last usage times.//现在我们知道了我们要保留的所有软件包。// 读取并更新它们的最后使用时间。mPackageUsage.read(packageSettings);mCompilerStats.read();

小结

这里就是对/data/app进行了扫描，主要工作与扫描系统App目录是一样的。

**阶段4：**BOOT_PROGRESS_PMS_SCAN_END

android-12.0.0_r28\frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

			EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_SCAN_END,SystemClock.uptimeMillis());Slog.i(TAG, "Time to scan packages: "+ ((SystemClock.uptimeMillis()-startTime)/1000f)+ " seconds");// If the build fingerprint has changed since the last time we booted,// we need to re-grant app permission to catch any new ones that// appear.  This is really a hack, and means that apps can in some// cases get permissions that the user didn't initially explicitly// allow...  it would be nice to have some better way to handle// this situation.if (mIsUpgrade) {Slog.i(TAG, "Build fingerprint changed from " + ver.fingerprint + " to "+ Build.FINGERPRINT + "; regranting permissions for internal storage");}// 如果在上次启动之后，build fingerprint发生了变化。// 就需要重新授予应用程序权限，以捕捉任何新出现的情况// 这意味着应用程序在某些情况下可以获得用户最初没有明确允许的权限。mPermissionManager.onStorageVolumeMounted(StorageManager.UUID_PRIVATE_INTERNAL, mIsUpgrade);ver.sdkVersion = mSdkVersion;// If this is the first boot or an update from pre-M, and it is a normal// boot, then we need to initialize the default preferred apps across// all defined users.// 如果这是第一次启动或从Android M之前的更新，并且是正常的启动// 那么我们就初始化所有定义的用户默认首选应用程序。if (!mOnlyCore && (mPromoteSystemApps || mFirstBoot)) {for (UserInfo user : mInjector.getUserManagerInternal().getUsers(true)) {mSettings.applyDefaultPreferredAppsLPw(user.id);}}// Prepare storage for system user really early during boot,// since core system apps like SettingsProvider and SystemUI// can't wait for user to start// 在启动过程中为系统用户真正提前准备好存储。// 因为核心系统应用程序（如 SettingsProvide r和 SystemUI）不能等待用户启动final int storageFlags;if (StorageManager.isFileEncryptedNativeOrEmulated()) {storageFlags = StorageManager.FLAG_STORAGE_DE;} else {storageFlags = StorageManager.FLAG_STORAGE_DE | StorageManager.FLAG_STORAGE_CE;}List deferPackages = reconcileAppsDataLI(StorageManager.UUID_PRIVATE_INTERNAL,UserHandle.USER_SYSTEM, storageFlags, true /* migrateAppData */,true /* onlyCoreApps */);mPrepareAppDataFuture = SystemServerInitThreadPool.submit(() -> {TimingsTraceLog traceLog = new TimingsTraceLog("SystemServerTimingAsync",Trace.TRACE_TAG_PACKAGE_MANAGER);traceLog.traceBegin("AppDataFixup");try {mInstaller.fixupAppData(StorageManager.UUID_PRIVATE_INTERNAL,StorageManager.FLAG_STORAGE_DE | StorageManager.FLAG_STORAGE_CE);} catch (InstallerException e) {Slog.w(TAG, "Trouble fixing GIDs", e);}traceLog.traceEnd();traceLog.traceBegin("AppDataPrepare");if (deferPackages == null || deferPackages.isEmpty()) {return;}int count = 0;final Installer.Batch batch = new Installer.Batch();for (String pkgName : deferPackages) {AndroidPackage pkg = null;synchronized (mLock) {PackageSetting ps = mSettings.getPackageLPr(pkgName);if (ps != null && ps.getInstalled(UserHandle.USER_SYSTEM)) {pkg = ps.pkg;}}if (pkg != null) {prepareAppDataAndMigrate(batch, pkg, UserHandle.USER_SYSTEM, storageFlags,true /* maybeMigrateAppData */);count++;}}synchronized (mInstallLock) {executeBatchLI(batch);}traceLog.traceEnd();Slog.i(TAG, "Deferred reconcileAppsData finished " + count + " packages");}, "prepareAppData");// If this is first boot after an OTA, and a normal boot, then// we need to clear code cache directories.// Note that we do *not* clear the application profiles. These remain valid// across OTAs and are used to drive profile verification (post OTA) and// profile compilation (without waiting to collect a fresh set of profiles).// 如果这是OTA后的第一次启动，而且是正常启动，// 那么我们就清除代码缓存目录。// 注意，我们并不清除应用程序配置文件。这些文件仍然有效// 在不同的OTA中都是有效的if (mIsUpgrade && !mOnlyCore) {Slog.i(TAG, "Build fingerprint changed; clearing code caches");for (int i = 0; i < packageSettings.size(); i++) {final PackageSetting ps = packageSettings.valueAt(i);if (Objects.equals(StorageManager.UUID_PRIVATE_INTERNAL, ps.volumeUuid)) {// No apps are running this early, so no need to freezeclearAppDataLIF(ps.pkg, UserHandle.USER_ALL,FLAG_STORAGE_DE | FLAG_STORAGE_CE | FLAG_STORAGE_EXTERNAL| Installer.FLAG_CLEAR_CODE_CACHE_ONLY| Installer.FLAG_CLEAR_APP_DATA_KEEP_ART_PROFILES);}}ver.fingerprint = Build.FINGERPRINT;}// Legacy existing (installed before Q) non-system apps to hide// their icons in launcher.// 在Q之前安装的非系统应用程序，隐藏它们在 Launch 中的图标。if (!mOnlyCore && mIsPreQUpgrade) {Slog.i(TAG, "Whitelisting all existing apps to hide their icons");int size = packageSettings.size();for (int i = 0; i < size; i++) {final PackageSetting ps = packageSettings.valueAt(i);if ((ps.pkgFlags & ApplicationInfo.FLAG_SYSTEM) != 0) {continue;}ps.disableComponentLPw(PackageManager.APP_DETAILS_ACTIVITY_CLASS_NAME,UserHandle.USER_SYSTEM);}}// clear only after permissions and other defaults have been updated// 只有在权限和其他默认值被更新后才能清除mPromoteSystemApps = false;// All the changes are done during package scanning.// 所有的变化都是在软件包扫描期间完成的ver.databaseVersion = Settings.CURRENT_DATABASE_VERSION;// can downgrade to readert.traceBegin("write settings");// 将信息写到 packages.xml 文件writeSettingsLPrTEMP();t.traceEnd();

小结

这里主要做了如下几件事情：

1. 如果SDK版本发生了变化（升级系统），重新对App进行授权
2. 为系统核心服务准备存储空间
3. 如果是升级后第一次正常启动，需要清除代码缓存，但不是会清除应用的配置文件
4. 把更新后的信息写回对应的xml文件中

**阶段5：**BOOT_PROGRESS_PMS_READY

android-12.0.0_r28\frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

			EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_READY,SystemClock.uptimeMillis());if (!mOnlyCore) {mRequiredVerifierPackage = getRequiredButNotReallyRequiredVerifierLPr();mRequiredInstallerPackage = getRequiredInstallerLPr();mRequiredUninstallerPackage = getRequiredUninstallerLPr();ComponentName intentFilterVerifierComponent =getIntentFilterVerifierComponentNameLPr();ComponentName domainVerificationAgent =getDomainVerificationAgentComponentNameLPr();DomainVerificationProxy domainVerificationProxy = DomainVerificationProxy.makeProxy(intentFilterVerifierComponent, domainVerificationAgent, mContext,mDomainVerificationManager, mDomainVerificationManager.getCollector(),mDomainVerificationConnection);mDomainVerificationManager.setProxy(domainVerificationProxy);mServicesExtensionPackageName = getRequiredServicesExtensionPackageLPr();mSharedSystemSharedLibraryPackageName = getRequiredSharedLibraryLPr(PackageManager.SYSTEM_SHARED_LIBRARY_SHARED,SharedLibraryInfo.VERSION_UNDEFINED);} else {mRequiredVerifierPackage = null;mRequiredInstallerPackage = null;mRequiredUninstallerPackage = null;mServicesExtensionPackageName = null;mSharedSystemSharedLibraryPackageName = null;}// PermissionController hosts default permission granting and role management, so it's a// critical part of the core system.// PermissionController主持默认的权限授予和角色管理，// 所以它是一个核心系统的关键部分mRequiredPermissionControllerPackage = getRequiredPermissionControllerLPr();mSettings.setPermissionControllerVersion(getPackageInfo(mRequiredPermissionControllerPackage, 0,UserHandle.USER_SYSTEM).getLongVersionCode());// Initialize InstantAppRegistry's Instant App list for all users.// 为所有用户初始化InstantAppRegistry的即时应用程序列表。for (AndroidPackage pkg : mPackages.values()) {if (pkg.isSystem()) {continue;}for (int userId : userIds) {final PackageSetting ps = getPackageSetting(pkg.getPackageName());if (ps == null || !ps.getInstantApp(userId) || !ps.getInstalled(userId)) {continue;}mInstantAppRegistry.addInstantAppLPw(userId, ps.appId);}}mInstallerService = mInjector.getPackageInstallerService();final ComponentName instantAppResolverComponent = getInstantAppResolverLPr();if (instantAppResolverComponent != null) {if (DEBUG_INSTANT) {Slog.d(TAG, "Set ephemeral resolver: " + instantAppResolverComponent);}mInstantAppResolverConnection =mInjector.getInstantAppResolverConnection(instantAppResolverComponent);mInstantAppResolverSettingsComponent =getInstantAppResolverSettingsLPr(instantAppResolverComponent);} else {mInstantAppResolverConnection = null;mInstantAppResolverSettingsComponent = null;}updateInstantAppInstallerLocked(null);// Read and update the usage of dex files.// Do this at the end of PM init so that all the packages have their// data directory reconciled.// At this point we know the code paths of the packages, so we can validate// the disk file and build the internal cache.// The usage file is expected to be small so loading and verifying it// should take a fairly small time compare to the other activities (e.g. package// scanning).// 读取并更新dex文件的用法。在PM init的结束时执行，// 以便协调所有的包都的数据目录。因为我们现在已经知道软件包的路径// 所以我们可以验证磁盘文件并建立内部缓存。// 预计使用文件会很小，所以加载和验证它与其他活动（如软件包扫描）相比// 应该只会花费相当少的时间。final Map> userPackages = new HashMap<>();for (int userId : userIds) {userPackages.put(userId, getInstalledPackages(/*flags*/ 0, userId).getList());}mDexManager.load(userPackages);if (mIsUpgrade) {FrameworkStatsLog.write(FrameworkStatsLog.BOOT_TIME_EVENT_DURATION_REPORTED,BOOT_TIME_EVENT_DURATION__EVENT__OTA_PACKAGE_MANAGER_INIT_TIME,SystemClock.uptimeMillis() - startTime);}// Rebild the live computer since some attributes have been rebuilt.// 由于一些属性已经被重建，所以要重新建立实时计算mLiveComputer = createLiveComputer();} // synchronized (mLock)} // synchronized (mInstallLock)// CHECKSTYLE:ON IndentationCheckmModuleInfoProvider = mInjector.getModuleInfoProvider();mInjector.getSystemWrapper().enablePackageCaches();// Now after opening every single application zip, make sure they// are all flushed.  Not really needed, but keeps things nice and// tidy.t.traceBegin("GC");VMRuntime.getRuntime().requestConcurrentGC();t.traceEnd();// The initial scanning above does many calls into installd while// holding the mPackages lock, but we're mostly interested in yelling// once we have a booted system.mInstaller.setWarnIfHeld(mLock);ParsingPackageUtils.readConfigUseRoundIcon(mContext.getResources());mServiceStartWithDelay = SystemClock.uptimeMillis() + (60 * 1000L);Slog.i(TAG, "Fix for b/169414761 is applied");

小结

• 创建PackageInstallerService对象

• GC回收内存