背景
PackageManagerService 简称 PMS 或者 PKMS。它主要负责对所有的系统app或者用户安装的app的扫描、安装、卸载、解析、dex优化等操作。 因此，只要是app想要安装到手机，都必须要到这个PKMS管理中心注册，只有通过验证才能真正的安装成功。
一、启动时机
SystemServer.java:
private void startBootstrapServices() {
...
traceBeginAndSlog("StartPackageManagerService");
try {
Watchdog.getInstance().pauseWatchingCurrentThread("packagemanagermain");
//mSystemContext: 系统的上下文, install:安装apk时的服务 mOnlyCore=false
mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF, mOnlyCore);
} finally {
Watchdog.getInstance().resumeWatchingCurrentThread("packagemanagermain");
}
mFirstBoot = mPackageManagerService.isFirstBoot();
//得到 pm对象
mPackageManager = mSystemContext.getPackageManager();
traceEnd();
...
}
mFactoryTestMode有三种模式，一般都是非工厂模式，即关闭状态。
FACTORY_TEST_OFF, FACTORY_TEST_LOW_LEVEL, or FACTORY_TEST_HIGH_LEVEL.
查看 PackageManagerService.main() 方法 :
二、 main()
PackageManagerService.java
public static PackageManagerService main(Context context, Installer installer,
boolean factoryTest, boolean onlyCore) {
// Self-check for initial settings. 自检
PackageManagerServiceCompilerMapping.checkProperties();
// 创建 PMS对象。
PackageManagerService m = new PackageManagerService(context, installer,
factoryTest, onlyCore);
m.enableSystemUserPackages();
// 往SM注册服务，名字为：package，服务：m
ServiceManager.addService("package", m);
// 创建 PackageManagerNative 服务，注册到SM
final PackageManagerNative pmn = m.new PackageManagerNative();
// 往SM注册服务，名字为：package_native，服务：pmn
ServiceManager.addService("package_native", pmn);
return m;
}
创建PKMS对象，构造方法中传入了installer 对象。 onlycore表示是否启动核心应用。如加密的情况下我们只启动核心服务。- 往SM中注册
package服务，服务对象为 PKMS 。 - 往SM中注册
package_native服务。对象为 PackageManagerNative
疑问： PackageManagerNative 是PMS的内部类。IPackageManagerNative是啥？
答： Parallel implementation of certain {@link PackageManager} APIs that need to be exposed to native code.
翻译： 跟PM类的接似的实现。这些方法是提供给native调用的。 虽然和PM的api很像，但是还是保持在两个不同的地方。
PackageManagerNative extends IPackageManagerNative.Stub{}
PMS 还有 一个内部类 PackageManagerInternalImpl 。
PackageManagerInternalImpl extends PackageManagerInternal
是PMS在本进程对外暴露的接口类。
三、PMS的 构造方法
构造方法很长，根据log打印可以分为 5 个阶段：
- EventLogTags.BOOT_PROGRESS_PMS_START： 启动阶段
- EventLogTags.BOOT_PROGRESS_PMS_SYSTEM_SCAN_START：系统扫描阶段
- EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START： data扫描阶段
- EventLogTags.BOOT_PROGRESS_PMS_SCAN_END： 扫描结束阶段
- EventLogTags.BOOT_PROGRESS_PMS_READY： 准备阶段
3.1 启动阶段 PMS_START
DisplayMetrics： 保存屏幕信息。
public PackageManagerService(Context context, Installer installer,
boolean factoryTest, boolean onlyCore) {
LockGuard.installLock(mPackages, LockGuard.INDEX_PACKAGES);
//
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "create package manager");
// 日志追踪
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_START,
SystemClock.uptimeMillis());
if (mSdkVersion <= 0) {
Slog.w(TAG, "**** ro.build.version.sdk not set!");
}
mContext = context;
mFactoryTest = factoryTest;
//
mOnlyCore = onlyCore;
// 1 存储屏幕相关信息
mMetrics = new DisplayMetrics();
// 安装服务。本身是 installd 进程的封装。真正是通过binder通信来实现
mInstaller = installer;
// Create sub-components that provide services / data. Order here is important.
// 2 进入同步锁 mInstallLock，安装apk时需要的锁
synchronized (mInstallLock) {
// 3 进入同步锁 mPackages // 更新apk时候需要的锁
synchronized (mPackages) {
// Expose private service for system components to use.
// 4，注册 PMInternalImpl 到LocalServices中，对外暴露PkMS的接口，方便本进程系统组件使用
LocalServices.addService(
PackageManagerInternal.class, new PackageManagerInternalImpl());
// 5. 用户管理服务
sUserManager = new UserManagerService(context, this,
new UserDataPreparer(mInstaller, mInstallLock, mContext, mOnlyCore), mPackages);
// 6. 组件解析器。 传入了 userManager、PKMS对外暴露的内部类对象、mPackages。
mComponentResolver = new ComponentResolver(sUserManager,
LocalServices.getService(PackageManagerInternal.class),
mPackages);
// 7, 权限管理服务
mPermissionManager = PermissionManagerService.create(context,
mPackages /*externalLock*/);
// 8，默认的权限的策略
mDefaultPermissionPolicy = mPermissionManager.getDefaultPermissionGrantPolicy();
// 9，Settings 保存了所有包的信息结构
mSettings = new Settings(Environment.getDataDirectory(),
mPermissionManager.getPermissionSettings(), mPackages);
}
} // 退出同步锁 mInstallLock mPackages
// 10, 把system、phone、log、nfc、bluetooth、shell、se、networkstack 8种 shareUserId 作为默认的
sharedUid 加入到 mSettings，
mSettings.addSharedUserLPw("android.uid.system", Process.SYSTEM_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.phone", RADIO_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.log", LOG_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.nfc", NFC_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.bluetooth", BLUETOOTH_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.shell", SHELL_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.se", SE_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
mSettings.addSharedUserLPw("android.uid.networkstack", NETWORKSTACK_UID,
ApplicationInfo.FLAG_SYSTEM, ApplicationInfo.PRIVATE_FLAG_PRIVILEGED);
String separateProcesses = SystemProperties.get("debug.separate_processes");
if (separateProcesses != null && separateProcesses.length() > 0) {
if ("*".equals(separateProcesses)) {
mDefParseFlags = PackageParser.PARSE_IGNORE_PROCESSES;
mSeparateProcesses = null;
Slog.w(TAG, "Running with debug.separate_processes: * (ALL)");
} else {
mDefParseFlags = 0;
mSeparateProcesses = separateProcesses.split(",");
Slog.w(TAG, "Running with debug.separate_processes: "
+ separateProcesses);
}
} else {
mDefParseFlags = 0;
mSeparateProcesses = null;
}
// 11 包优化器
mPackageDexOptimizer = new PackageDexOptimizer(installer, mInstallLock, context,
"*dexopt*");
// 12 dex管理者,追踪dex文件的过程
mDexManager = new DexManager(mContext, this, mPackageDexOptimizer, installer, mInstallLock);
// 13 art管理服务
mArtManagerService = new ArtManagerService(mContext, this, installer, mInstallLock);
// 14 android.fg线程 的handler
mMoveCallbacks = new MoveCallbacks(FgThread.get().getLooper());
mViewCompiler = new ViewCompiler(mInstallLock, mInstaller);
mOnPermissionChangeListeners = new OnPermissionChangeListeners(
FgThread.get().getLooper());
// 获取屏幕信息
getDefaultDisplayMetrics(context, mMetrics);
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "get system config");
// 开始获取系统配置
SystemConfig systemConfig = SystemConfig.getInstance();
mAvailableFeatures = systemConfig.getAvailableFeatures();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
mProtectedPackages = new ProtectedPackages(mContext);
mApexManager = new ApexManager(context);
// 进入同步锁 mInstallLock 、mPackages
synchronized (mInstallLock) {
// writer
synchronized (mPackages) {
// 创建并启动后台线程
mHandlerThread = new ServiceThread(TAG,
Process.THREAD_PRIORITY_BACKGROUND, true /*allowIo*/);
mHandlerThread.start();
// 创建 mHandler.
mHandler = new PackageHandler(mHandlerThread.getLooper());
mProcessLoggingHandler = new ProcessLoggingHandler();
// Watchdog监测这个 packageHandler 线程
Watchdog.getInstance().addThread(mHandler, WATCHDOG_TIMEOUT);
// InstantAppRegistry
mInstantAppRegistry = new InstantAppRegistry(this);
// 公共库
ArrayMap<String, SystemConfig.SharedLibraryEntry> libConfig
= systemConfig.getSharedLibraries();
final int builtInLibCount = libConfig.size();
for (int i = 0; i < builtInLibCount; i++) {
String name = libConfig.keyAt(i);
SystemConfig.SharedLibraryEntry entry = libConfig.valueAt(i);
// 遍历共享库，加入到内嵌的lib中 ？？
addBuiltInSharedLibraryLocked(entry.filename, name);
}
// Now that we have added all the libraries, iterate again to add dependency
// information IFF their dependencies are added.
long undefinedVersion = SharedLibraryInfo.VERSION_UNDEFINED;
// 再次遍历内嵌的公共库，添加依赖
for (int i = 0; i < builtInLibCount; i++) {
String name = libConfig.keyAt(i);
SystemConfig.SharedLibraryEntry entry = libConfig.valueAt(i);
final int dependencyCount = entry.dependencies.length;
for (int j = 0; j < dependencyCount; j++) {
final SharedLibraryInfo dependency =
getSharedLibraryInfoLPr(entry.dependencies[j], undefinedVersion);
if (dependency != null) {
getSharedLibraryInfoLPr(name, undefinedVersion).addDependency(dependency);
}
}
}
SELinuxMMAC.readInstallPolicy();
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "loadFallbacks");
FallbackCategoryProvider.loadFallbacks();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "read user settings");
// mSettings 解析 data/system/ 目录中的 packages.xml 等文件
mFirstBoot = !mSettings.readLPw(sUserManager.getUsers(false));
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
// Clean up orphaned packages for which the code path doesn't exist
// and they are an update to a system app - caused by bug/32321269
// 遍历所有安装的包 mPackages，移除无效包
final int packageSettingCount = mSettings.mPackages.size();
for (int i = packageSettingCount - 1; i >= 0; i--) {
PackageSetting ps = mSettings.mPackages.valueAt(i);
if (!isExternal(ps) && (ps.codePath == null || !ps.codePath.exists())
&& mSettings.getDisabledSystemPkgLPr(ps.name) != null) {
mSettings.mPackages.removeAt(i);
mSettings.enableSystemPackageLPw(ps.name);
}
}
// 第一次启动且没有加密，则把system部分拷贝到data中去。实际init进程已经完成了拷贝，这里只是确认下。
if (!mOnlyCore && mFirstBoot) {
requestCopyPreoptedFiles();
}
String customResolverActivityName = Resources.getSystem().getString(
R.string.config_customResolverActivity);
if (!TextUtils.isEmpty(customResolverActivityName)) {
mCustomResolverComponentName = ComponentName.unflattenFromString(
customResolverActivityName);
}
} // 退出锁
总结：
- 初始化了
多用户管理服务、权限管理服务、art管理服务、Settings设置。 Settings中包含了所有包的信息。 - 把system、phone、log、nfc、bluetooth、shell、se、networkstack 8种
shareUserId加入到mSettings。因为 两个apk如果设置了相同的SharedUid，且签名一致则可以运行在同一个进程，实现共享数据。 - 初始化 PackageDexOptimizer和DexManager 用来做dex优化类、dex管理者、
- 获取屏幕信息
DisplayMetrics - 获取系统全局配置 SystemConfig，完成权限的读取。添加共享的公共库
- 创建
PackageManager线程，同时绑定PackageHandler。Watchdog 检测该线程，防止由于工作太多导致无响应 mSettings解析 data/system/ 目录中的 packages.xml 等文件。packages.xml 保存了所有安装的包的信息，包含fingerprint指纹、签名、权限等基本信息。 如果 readLPw()方法返回true，mFirsBoot则为false，表示已经初始化过了。- 移除无效包、继续初始化
3.1.1 创建 Settings
Settings(File dataDir, PermissionSettings permission,
Object lock) {
mLock = lock;
mPermissions = permission;
mRuntimePermissionsPersistence = new RuntimePermissionPersistence(mLock);
mSystemDir = new File(dataDir, "system");
//创建 /data/system/ 目录
mSystemDir.mkdirs();
FileUtils.setPermissions(mSystemDir.toString(),
FileUtils.S_IRWXU|FileUtils.S_IRWXG
|FileUtils.S_IROTH|FileUtils.S_IXOTH,
-1, -1);
mSettingsFilename = new File(mSystemDir, "packages.xml");
mBackupSettingsFilename = new File(mSystemDir, "packages-backup.xml");
mPackageListFilename = new File(mSystemDir, "packages.list");
FileUtils.setPermissions(mPackageListFilename, 0640, SYSTEM_UID, PACKAGE_INFO_GID);
final File kernelDir = new File("/config/sdcardfs");
mKernelMappingFilename = kernelDir.exists() ? kernelDir : null;
// Deprecated: Needed for migration
mStoppedPackagesFilename = new File(mSystemDir, "packages-stopped.xml");
mBackupStoppedPackagesFilename = new File(mSystemDir, "packages-stopped-backup.xml");
}
创建 /data/system/ 目录。同时在该目录下创建如下文件：
- packages.xml 记录所有安装包的基本信息。如：签名、sharedUid、指纹footprint等
- packages.list 记录应用的数据信息
- packages-stopped.xml 记录被强制停止的文件
- packages-stopped-backup.xml 备份文件
3.1.2 SystemConfig.getInstance()
SystemConfig() {
// Read configuration from system
readPermissions(Environment.buildPath(
Environment.getRootDirectory(), "etc", "sysconfig"), ALLOW_ALL);
// Read configuration from the old permissions dir
readPermissions(Environment.buildPath(
Environment.getRootDirectory(), "etc", "permissions"), ALLOW_ALL);
// Vendors are only allowed to customize these
int vendorPermissionFlag = ALLOW_LIBS | ALLOW_FEATURES | ALLOW_PRIVAPP_PERMISSIONS
| ALLOW_ASSOCIATIONS;
if (Build.VERSION.FIRST_SDK_INT <= Build.VERSION_CODES.O_MR1) {
// For backward compatibility
vendorPermissionFlag |= (ALLOW_PERMISSIONS | ALLOW_APP_CONFIGS);
}
readPermissions(Environment.buildPath(
Environment.getVendorDirectory(), "etc", "sysconfig"), vendorPermissionFlag);
readPermissions(Environment.buildPath(
Environment.getVendorDirectory(), "etc", "permissions"), vendorPermissionFlag);
// Allow ODM to customize system configs as much as Vendor, because /odm is another
// vendor partition other than /vendor.
int odmPermissionFlag = vendorPermissionFlag;
readPermissions(Environment.buildPath(
Environment.getOdmDirectory(), "etc", "sysconfig"), odmPermissionFlag);
readPermissions(Environment.buildPath(
Environment.getOdmDirectory(), "etc", "permissions"), odmPermissionFlag);
String skuProperty = SystemProperties.get(SKU_PROPERTY, "");
if (!skuProperty.isEmpty()) {
String skuDir = "sku_" + skuProperty;
readPermissions(Environment.buildPath(
Environment.getOdmDirectory(), "etc", "sysconfig", skuDir), odmPermissionFlag);
readPermissions(Environment.buildPath(
Environment.getOdmDirectory(), "etc", "permissions", skuDir),
odmPermissionFlag);
}
// Allow OEM to customize these
int oemPermissionFlag = ALLOW_FEATURES | ALLOW_OEM_PERMISSIONS | ALLOW_ASSOCIATIONS;
readPermissions(Environment.buildPath(
Environment.getOemDirectory(), "etc", "sysconfig"), oemPermissionFlag);
readPermissions(Environment.buildPath(
Environment.getOemDirectory(), "etc", "permissions"), oemPermissionFlag);
// Allow Product to customize all system configs
readPermissions(Environment.buildPath(
Environment.getProductDirectory(), "etc", "sysconfig"), ALLOW_ALL);
readPermissions(Environment.buildPath(
Environment.getProductDirectory(), "etc", "permissions"), ALLOW_ALL);
// Allow /product_services to customize all system configs
readPermissions(Environment.buildPath(
Environment.getProductServicesDirectory(), "etc", "sysconfig"), ALLOW_ALL);
readPermissions(Environment.buildPath(
Environment.getProductServicesDirectory(), "etc", "permissions"), ALLOW_ALL);
}
读取指定目录的权限。
在PKMS 初始化完成后，就开始真正的扫描和安装阶段的工作了。 首先扫描的位置 system/ 目录。
3.2 system扫描阶段 SYSTEM_SCAN_START
long startTime = SystemClock.uptimeMillis();
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_SYSTEM_SCAN_START,
startTime);
// 获取 bootClass 的路径 如 system/framework 目录下的 content.jar、framework.jar、input.jar等。
final String bootClassPath = System.getenv("BOOTCLASSPATH");
// 主要包括 system/framework/ 目录下的 services.jar、ethernet-service.jar、wifi-services.jar三个文件
final String systemServerClassPath = System.getenv("SYSTEMSERVERCLASSPATH");
...
// /system/framework 目录
File frameworkDir = new File(Environment.getRootDirectory(), "framework");
final VersionInfo ver = mSettings.getInternalVersion();
// 版本指纹不一样则更新
mIsUpgrade = !Build.FINGERPRINT.equals(ver.fingerprint);
if (mIsUpgrade) {
logCriticalInfo(Log.INFO,
"Upgrading from " + ver.fingerprint + " to " + Build.FINGERPRINT);
}
// when upgrading from pre-M, promote system app permissions from install to runtime
// 在 Android6.0 之前升级的版本，则调整动态权限
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.
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;
int preUpgradeSdkVersion = ver.sdkVersion;
// save off the names of pre-existing system packages prior to scanning; we don't
// want to automatically grant runtime permissions for new system apps
if (mPromoteSystemApps) {
Iterator<PackageSetting> pkgSettingIter = mSettings.mPackages.values().iterator();
while (pkgSettingIter.hasNext()) {
PackageSetting ps = pkgSettingIter.next();
if (isSystemApp(ps)) {
mExistingSystemPackages.add(ps.name);
}
}
}
...
// Collect vendor/product/product_services 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.
// 扫描 /vendor/overlay 目录下的文件
scanDirTracedLI(new File(VENDOR_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR,
0);
// 扫描 /product/overlay 目录下的文件
scanDirTracedLI(new File(PRODUCT_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT,
0);
// 扫描 /product_services/overlay 目录下的文件
scanDirTracedLI(new File(PRODUCT_SERVICES_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES,
0);
// 扫描 /odm/overlay 目录下的文件
scanDirTracedLI(new File(ODM_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_ODM,
0);
// 扫描 /oem/overlay 目录下的文件
scanDirTracedLI(new File(OEM_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_OEM,
0);
mParallelPackageParserCallback.findStaticOverlayPackages();
// Find base frameworks (resource packages without code).
// 在 system/framework 目录下查找资源包，不包含代码
scanDirTracedLI(frameworkDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_NO_DEX
| SCAN_AS_SYSTEM
| SCAN_AS_PRIVILEGED,
0);
// 其实为了找framework.res.apk
if (!mPackages.containsKey("android")) {
throw new IllegalStateException(
"Failed to load frameworks package; check log for warnings");
}
// Collect privileged system packages.
// 扫描收集私有特权的系统包： system/priv_app 目录的包文件
final File privilegedAppDir = new File(Environment.getRootDirectory(), "priv-app");
scanDirTracedLI(privilegedAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRIVILEGED,
0);
// Collect ordinary system packages.
// 扫描收集普通系统包： system/app 目录的包文件
final File systemAppDir = new File(Environment.getRootDirectory(), "app");
scanDirTracedLI(systemAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM,
0);
// Collect privileged vendor packages.
File privilegedVendorAppDir = new File(Environment.getVendorDirectory(), "priv-app");
try {
privilegedVendorAppDir = privilegedVendorAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
// vender/priv-app
scanDirTracedLI(privilegedVendorAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR
| SCAN_AS_PRIVILEGED,
0);
// Collect ordinary vendor packages.
File vendorAppDir = new File(Environment.getVendorDirectory(), "app");
try {
vendorAppDir = vendorAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
// vender/app
scanDirTracedLI(vendorAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR,
0);
// Collect privileged odm packages. /odm is another vendor partition
// other than /vendor.
File privilegedOdmAppDir = new File(Environment.getOdmDirectory(),
"priv-app");
//除了 vender/app和vender/priv-app，还有 odm/app和odm/priv-app、oem/app和oem/priv-app
product/app和product/priv-app、product_services/app和product_services/priv-app目录，也会扫描。
...
// Prune any system packages that no longer exist.
// 可能需要删除的系统 app
final List<String> possiblyDeletedUpdatedSystemApps = new ArrayList<>();
// Stub packages must either be replaced with full versions in the /data
// partition or be disabled.
final List<String> stubSystemApps = new ArrayList<>();
// 收集有可能需要删除的系统app
if (!mOnlyCore) {
// do this first before mucking with mPackages for the "expecting better" case
final Iterator<PackageParser.Package> pkgIterator = mPackages.values().iterator();
while (pkgIterator.hasNext()) {
final PackageParser.Package pkg = pkgIterator.next();
if (pkg.isStub) {
stubSystemApps.add(pkg.packageName);
}
}
final Iterator<PackageSetting> psit = mSettings.mPackages.values().iterator();
while (psit.hasNext()) {
PackageSetting ps = psit.next();
/*
* 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 PackageParser.Package 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)) {
// 如果存在，且同时被标记了，返回true则表示已经更新了
logCriticalInfo(Log.WARN,
"Expecting better updated system app for " + ps.name
+ "; removing system app. Last known"
+ " codePath=" + ps.codePathString
+ ", versionCode=" + ps.versionCode
+ "; scanned versionCode=" + scannedPkg.getLongVersionCode());
removePackageLI(scannedPkg, true);
// 表示已经升级过了，是OAT升级包，作为更好的选择
mExpectingBetter.put(ps.name, ps.codePath);
}
continue;
}
if (!mSettings.isDisabledSystemPackageLPr(ps.name)) {
// 如果没有被标记，则移除。
psit.remove();
logCriticalInfo(Log.WARN, "System package " + ps.name
+ " no longer exists; it's data will be wiped");
// Actual deletion of code and data will be handled by later
// reconciliation step
} else {
// 如果被标记为 disabled
// 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.codePath == null || !disabledPs.codePath.exists()
|| disabledPs.pkg == null) {
// system的代码文件不存在， 则加入到可能被移除的列表。由于此时没法确定，只能等到扫描完data
分区后才能确定！！
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.
// 如果system的文件存在，则认为无更新。统一加入到已升级的列表中
mExpectingBetter.put(disabledPs.name, disabledPs.codePath);
}
}
}
}
//delete tmp files
deleteTempPackageFiles();
final int cachedSystemApps = PackageParser.sCachedPackageReadCount.get();
// Remove any shared userIDs that have no associated packages
mSettings.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) {
MetricsLogger.histogram(null, "ota_package_manager_system_app_avg_scan_time",
((int) systemScanTime) / systemPackagesCount);
}
总结：
- 从
init.rc文件中得到环境变量：bootClassPath和systemClassPath。即system/framework下的系统共享库。如 xxx.jar。 - 对于Android6.0之前升级上来的版本，进行权限调整。从安装时候授权改为动态申请
- 扫描 vendor/product/product_services、system/framewrok等目录。
- 遍历 mPackages所有包，区分出有可能被移除的
系统app，加入possiblyDeletedUpdatedSystemApps，以及已经更新完成的系统app，加入mExpectingBetter。
可以通过adb shell env 来查看系统的环境变量，如 bootClassPath 。
3.2.1 系统app的三种更新逻辑
- 无更新
- 有更新 在新的OAT版本中，这个系统app有更新
- 被移除 在新的OAT版本中，这个系统app被移除
- 当 PKMS 的mSettings中的系统app被标记(
isDisabledSystemPackageLPr()返回true)，且pkg存在mPackage中，则认为系统app已经更新了，则加入到mExpectingBetter。 - 没有被标记，则移除。
- 没有被标记，如果在system/目录下却找不到，最认为可能会被移除则加入
possiblyDeletedUpdatedSystemApps；如果找到了则认为是无更新，统一加入mExpectingBetter。
3.2.2 system/ 目录下的子目录
- system/app : 系统的应用。Android系统内置app或者厂商的app
- system/framework ： 存放framework框架层的jar包
- system/priv-app ： 存放特权app
- system/lib ： 存放系统公共库 so
- system/fonts ： 存放系统的字体
- system/media ： 存放闹钟的声音、通知的声音等文件
3.3 data扫描阶段 DATA_SCAN_START
// data/app
private static final File sAppInstallDir =
new File(Environment.getDataDirectory(), "app");
// false 表示没有加密。开始扫描data区
if (!mOnlyCore) {
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START,
SystemClock.uptimeMillis());
// 扫描 /data/app/ 目录
// 扫描apk，解析得到 application、activity、service、broadcast、providers等信息。
scanDirTracedLI(sAppInstallDir, 0, scanFlags | SCAN_REQUIRE_KNOWN, 0);
// 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.
// 删除可能需要删除的包
for (int i = possiblyDeletedUpdatedSystemApps.size() - 1; i >= 0; --i) {
final String packageName = possiblyDeletedUpdatedSystemApps.get(i);
// 从mPackages中获取 pkg
final PackageParser.Package 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
mSettings.removeDisabledSystemPackageLPw(packageName);
if (pkg == null) {
// should have found an update, but, we didn't; remove everything
// data分区也找不到。那就删除这些数据
msg = "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 privileges
//找到了，需要去除系统特权标识
msg = "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
//移除特权
removePackageLI(pkg, true);
try {
final File codePath = new File(pkg.applicationInfo.getCodePath());
//当做普通app，重新扫描这个包
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.mPackages.get(packageName);
if (ps != null && mPackages.get(packageName) == null) {
removePackageDataLIF(ps, null, 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.
*/
// 遍历mExpectingBetter列表，表示最终要展示的系统app
for (int i = 0; i < mExpectingBetter.size(); i++) {
final String packageName = mExpectingBetter.keyAt(i);
//如果在data分区中也没有找到，则可能在OAT升级过程中被清除数据。那么需要重新扫描system/app、system/priv-app等系统目录
if (!mPackages.containsKey(packageName)) {
final File scanFile = mExpectingBetter.valueAt(i);
logCriticalInfo(Log.WARN, "Expected better " + packageName
+ " but never showed up; reverting to system");
final @ParseFlags int reparseFlags;
final @ScanFlags int rescanFlags;
if (FileUtils.contains(privilegedAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRIVILEGED;
} else if (FileUtils.contains(systemAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM;
} else if (FileUtils.contains(privilegedVendorAppDir, scanFile)
|| FileUtils.contains(privilegedOdmAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR
| SCAN_AS_PRIVILEGED;
} else if (FileUtils.contains(vendorAppDir, scanFile)
|| FileUtils.contains(odmAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR;
} else if (FileUtils.contains(oemAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_OEM;
} else if (FileUtils.contains(privilegedProductAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT
| SCAN_AS_PRIVILEGED;
} else if (FileUtils.contains(productAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT;
} else if (FileUtils.contains(privilegedProductServicesAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES
| SCAN_AS_PRIVILEGED;
} else if (FileUtils.contains(productServicesAppDir, scanFile)) {
reparseFlags =
mDefParseFlags |
PackageParser.PARSE_IS_SYSTEM_DIR;
rescanFlags =
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES;
} else {
Slog.e(TAG, "Ignoring unexpected fallback path " + scanFile);
continue;
}
//更新settings中的 packageSetting参数为true
mSettings.enableSystemPackageLPw(packageName);
try {
// 扫描系统App的升级包
scanPackageTracedLI(scanFile, reparseFlags, rescanFlags, 0, null);
} catch (PackageManagerException e) {
Slog.e(TAG, "Failed to parse original system package: "
+ e.getMessage());
}
}
}
// Uncompress and install any stubbed system applications.
// 解压和安装 系统应用 app
// This must be done last to ensure all stubs are replaced or disabled.
installSystemStubPackages(stubSystemApps, scanFlags);
final int cachedNonSystemApps = PackageParser.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) {
MetricsLogger.histogram(null, "ota_package_manager_data_app_avg_scan_time",
((int) dataScanTime) / dataPackagesCount);
}
}
//安装完了，可以清空
mExpectingBetter.clear();
// Resolve the storage manager.
// storage 解析类
mStorageManagerPackage = getStorageManagerPackageName();
// Resolve protected action filters. Only the setup wizard is allowed to
// have a high priority filter for these actions.
// 解析intent-filters，
mSetupWizardPackage = getSetupWizardPackageName();
mComponentResolver.fixProtectedFilterPriorities();
mSystemTextClassifierPackage = getSystemTextClassifierPackageName();
mWellbeingPackage = getWellbeingPackageName();
mDocumenterPackage = getDocumenterPackageName();
mConfiguratorPackage =
mContext.getString(R.string.config_deviceConfiguratorPackageName);
mAppPredictionServicePackage = getAppPredictionServicePackageName();
mIncidentReportApproverPackage = getIncidentReportApproverPackageName();
// Now that we know all of the shared libraries, update all clients to have
// the correct library paths.
updateAllSharedLibrariesLocked(null, Collections.unmodifiableMap(mPackages));
// 更新共享库路径
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<String> changedAbiCodePath =
adjustCpuAbisForSharedUserLPw(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.
setting.fixSeInfoLocked();
}
// Now that we know all the packages we are keeping,
// read and update their last usage times.
mPackageUsage.read(mPackages);
mCompilerStats.read();
总结：
- 扫描
/data/app/目录。解析apk，解析得到application、activity、service、broadcast、providers等信息。保存到mPackages中。 - 遍历
possiblyDeletedUpdatedSystemApps可能要删除的系统app列表，检查升级文件名是否存在mPacakages中，如果不存在则说明在data分区也没找到，是残留信息，确实要删除；如果在data分区存在，则说明是system目录下文件可能被移除了。那么就移除系统特权，以普通app的权限再次扫描。 - 遍历
mExpectingBetter列表中的系统app，理论上应该在data分区能够找对应的目录，此时不作额外处理。但是如果在data分区找不到，那么就认为可能在OAT升级过程中被用户清除了，所以需要再次扫描system分区。 - 开始
安装系统app - 更新共享库的路径
3.3.1 data/ 目录的子目录
- /data/app :存储用户自己安装的app。包含apk、优化后的lat文件、so库。
- /data/data : 存放所有已安装的App数据，根据包名划分子目录
- /data/app-private： app的私有存储空间
- /data/app-lib ：存储所有app的jni库
- /data/system ：存放系统的配置文件
- /data/anr ： 存放anr发生时候的trace文件
3.4 扫描结束阶段
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_SCAN_END,
SystemClock.uptimeMillis());
Slog.i(TAG, "Time to scan packages: "
+ ((SystemClock.uptimeMillis()-startTime)/1000f)
+ " seconds");
// If the platform SDK 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.
// 如果此次 sdk 升级的版本不一致
final boolean sdkUpdated = (ver.sdkVersion != mSdkVersion);
if (sdkUpdated) {
Slog.i(TAG, "Platform changed from " + ver.sdkVersion + " to "
+ mSdkVersion + "; regranting permissions for internal storage");
}
// 如果此次 sdk 升级的版本不一致，则更新所以packages的权限
mPermissionManager.updateAllPermissions(
StorageManager.UUID_PRIVATE_INTERNAL, sdkUpdated, mPackages.values(),
mPermissionCallback);
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.
// 如果是第一次启动，或者是更新完Android6.0之后的第一次启动，则初始化默认首选app
if (!onlyCore && (mPromoteSystemApps || mFirstBoot)) {
for (UserInfo user : sUserManager.getUsers(true)) {
mSettings.applyDefaultPreferredAppsLPw(user.id);
primeDomainVerificationsLPw(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
final int storageFlags;
if (StorageManager.isFileEncryptedNativeOrEmulated()) {
storageFlags = StorageManager.FLAG_STORAGE_DE;
} else {
storageFlags = StorageManager.FLAG_STORAGE_DE | StorageManager.FLAG_STORAGE_CE;
}
List<String> deferPackages = reconcileAppsDataLI(StorageManager.UUID_PRIVATE_INTERNAL,
UserHandle.USER_SYSTEM, storageFlags, true /* migrateAppData */,
true /* onlyCoreApps */);
mPrepareAppDataFuture = SystemServerInitThreadPool.get().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;
for (String pkgName : deferPackages) {
PackageParser.Package pkg = null;
synchronized (mPackages) {
PackageSetting ps = mSettings.getPackageLPr(pkgName);
if (ps != null && ps.getInstalled(UserHandle.USER_SYSTEM)) {
pkg = ps.pkg;
}
}
if (pkg != null) {
synchronized (mInstallLock) {
prepareAppDataAndMigrateLIF(pkg, UserHandle.USER_SYSTEM, storageFlags,
true /* maybeMigrateAppData */);
}
count++;
}
}
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).
if (mIsUpgrade && !onlyCore) {
Slog.i(TAG, "Build fingerprint changed; clearing code caches");
// 如果升级了版本，且第一次启动OAT，清楚appdata目录下的代码缓存
for (int i = 0; i < mSettings.mPackages.size(); i++) {
final PackageSetting ps = mSettings.mPackages.valueAt(i);
if (Objects.equals(StorageManager.UUID_PRIVATE_INTERNAL, ps.volumeUuid)) {
// No apps are running this early, so no need to freeze
clearAppDataLIF(ps.pkg, UserHandle.USER_ALL,
FLAG_STORAGE_DE | FLAG_STORAGE_CE | FLAG_STORAGE_EXTERNAL
| Installer.FLAG_CLEAR_CODE_CACHE_ONLY);
}
}
ver.fingerprint = Build.FINGERPRINT;
}
// Grandfather existing (installed before Q) non-system apps to hide
// their icons in launcher.
if (!onlyCore && mIsPreQUpgrade) {
Slog.i(TAG, "Whitelisting all existing apps to hide their icons");
int size = mSettings.mPackages.size();
for (int i = 0; i < size; i++) {
final PackageSetting ps = mSettings.mPackages.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
mExistingSystemPackages.clear();
mPromoteSystemApps = false;
// All the changes are done during package scanning.
ver.databaseVersion = Settings.CURRENT_DATABASE_VERSION;
// can downgrade to reader
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "write settings");
//更新 settings
mSettings.writeLPr();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
总结：
- 如果OAT版本不一致，则更新所有权限
- 如果是第一次启动，或者是更新完Android6.0之后的第一次启动，则初始化默认首选app
- 如果升级OAT后第一次启动，清除代码缓存目录
- 更新settings内容到
package.xml
3.5 准备阶段 PMS_READY
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_READY,
SystemClock.uptimeMillis());
if (!mOnlyCore) {
mRequiredVerifierPackage = getRequiredButNotReallyRequiredVerifierLPr();
mRequiredInstallerPackage = getRequiredInstallerLPr();
mRequiredUninstallerPackage = getRequiredUninstallerLPr();
mIntentFilterVerifierComponent = getIntentFilterVerifierComponentNameLPr();
if (mIntentFilterVerifierComponent != null) {
mIntentFilterVerifier = new IntentVerifierProxy(mContext,
mIntentFilterVerifierComponent);
} else {
mIntentFilterVerifier = null;
}
mServicesSystemSharedLibraryPackageName = getRequiredSharedLibraryLPr(
PackageManager.SYSTEM_SHARED_LIBRARY_SERVICES,
SharedLibraryInfo.VERSION_UNDEFINED);
mSharedSystemSharedLibraryPackageName = getRequiredSharedLibraryLPr(
PackageManager.SYSTEM_SHARED_LIBRARY_SHARED,
SharedLibraryInfo.VERSION_UNDEFINED);
} else {
mRequiredVerifierPackage = null;
mRequiredInstallerPackage = null;
mRequiredUninstallerPackage = null;
mIntentFilterVerifierComponent = null;
mIntentFilterVerifier = null;
mServicesSystemSharedLibraryPackageName = null;
mSharedSystemSharedLibraryPackageName = null;
}
// PermissionController hosts default permission granting and role management, so it's a
// critical part of the core system.
mRequiredPermissionControllerPackage = getRequiredPermissionControllerLPr();
// Initialize InstantAppRegistry's Instant App list for all users.
final int[] userIds = UserManagerService.getInstance().getUserIds();
for (PackageParser.Package pkg : mPackages.values()) {
if (pkg.isSystem()) {
continue;
}
for (int userId : userIds) {
final PackageSetting ps = (PackageSetting) pkg.mExtras;
if (ps == null || !ps.getInstantApp(userId) || !ps.getInstalled(userId)) {
continue;
}
mInstantAppRegistry.addInstantAppLPw(userId, ps.appId);
}
}
// 安装服务
mInstallerService = new PackageInstallerService(context, this, mApexManager);
final Pair<ComponentName, String> instantAppResolverComponent =
getInstantAppResolverLPr();
if (instantAppResolverComponent != null) {
if (DEBUG_INSTANT) {
Slog.d(TAG, "Set ephemeral resolver: " + instantAppResolverComponent);
}
mInstantAppResolverConnection = new InstantAppResolverConnection(
mContext, instantAppResolverComponent.first,
instantAppResolverComponent.second);
mInstantAppResolverSettingsComponent =
getInstantAppResolverSettingsLPr(instantAppResolverComponent.first);
} 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).
final Map<Integer, List<PackageInfo>> userPackages = new HashMap<>();
for (int userId : userIds) {
userPackages.put(userId, getInstalledPackages(/*flags*/ 0, userId).getList());
}
// 加载 dex文件
mDexManager.load(userPackages);
if (mIsUpgrade) {
MetricsLogger.histogram(null, "ota_package_manager_init_time",
(int) (SystemClock.uptimeMillis() - startTime));
}
} // synchronized (mPackages)
} // synchronized (mInstallLock)
mModuleInfoProvider = new ModuleInfoProvider(mContext, this);
// Now after opening every single application zip, make sure they
// are all flushed. Not really needed, but keeps things nice and
// tidy.
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "GC");
// 调用gc，回收垃圾
Runtime.getRuntime().gc();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
// 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(mPackages);
PackageParser.readConfigUseRoundIcon(mContext.getResources());
mServiceStartWithDelay = SystemClock.uptimeMillis() + (60 * 1000L);
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
总结：
- 创建
PackageInstallerService对象，用来安装apk时使用 - 主动
gc，清理虚拟机内存
四、dex 优化
在 systemServer的 startOtherServices()方法中会调用 PKMS的方法：
private void startCoreServices() {
...
if (!mOnlyCore) {
traceBeginAndSlog("UpdatePackagesIfNeeded");
try {
Watchdog.getInstance().pauseWatchingCurrentThread("dexopt");
// 1 dex优化
mPackageManagerService.updatePackagesIfNeeded();
} catch (Throwable e) {
reportWtf("update packages", e);
} finally {
Watchdog.getInstance().resumeWatchingCurrentThread("dexopt");
}
traceEnd();
}
traceBeginAndSlog("PerformFstrimIfNeeded");
try {
// 执行ftrim
mPackageManagerService.performFstrimIfNeeded();
} catch (Throwable e) {
reportWtf("performing fstrim", e);
}
traceEnd();
...
traceBeginAndSlog("MakePackageManagerServiceReady");
// 3 调用 systemReady() 方法
mPackageManagerService.systemReady();
...
// Wait for all packages to be prepared
4. 等待所以的包安装完成
mPackageManagerService.waitForAppDataPrepared();
} ...
}
updatePackagesIfNeeded(),内部会调用 performDexOptUpgrade() 进行dex优化- 磁盘清理 ，清理空间
systemReady(),默认授权和更新package的信息,通知 PKMS相关对象已经初始化完成- 等待
所有的包安装完成
4.1 updatePackagesIfNeeded()
public void updatePackagesIfNeeded() {
// 必须是system 或者root 才可以访问
enforceSystemOrRoot("Only the system can request package update");
// We need to re-extract after an OTA.
在OAT更新后，重新抽取
boolean causeUpgrade = isDeviceUpgrading();
// First boot or factory reset.
// Note: we also handle devices that are upgrading to N right now as if it is their
// first boot, as they do not have profile data.
// 第一次启动
boolean causeFirstBoot = isFirstBoot() || mIsPreNUpgrade;
// We need to re-extract after a pruned cache, as AoT-ed files will be out of date.
// 是否清理过虚拟机的缓存
boolean causePrunedCache = VMRuntime.didPruneDalvikCache();
// 如果 没有OAT升级，也不是第一次启动，也没有清理过虚拟机的缓存，那么就无需dex优化。
if (!causeUpgrade && !causeFirstBoot && !causePrunedCache) {
return;
}
List<PackageParser.Package> pkgs;
synchronized (mPackages) {
// 获取需要dex优化的包。排序规则： core apps > system apps > other apps
pkgs = PackageManagerServiceUtils.getPackagesForDexopt(mPackages.values(), this);
}
final long startTime = System.nanoTime();
//按照排序后，执行 dex优化。内部最终通过 mInstaller.dexopt 来执行真正的dex优化
final int[] stats = performDexOptUpgrade(pkgs, mIsPreNUpgrade /* showDialog */,
causeFirstBoot ? REASON_FIRST_BOOT : REASON_BOOT,
false /* bootComplete */);
final int elapsedTimeSeconds =
(int) TimeUnit.NANOSECONDS.toSeconds(System.nanoTime() - startTime);
MetricsLogger.histogram(mContext, "opt_dialog_num_dexopted", stats[0]);
MetricsLogger.histogram(mContext, "opt_dialog_num_skipped", stats[1]);
MetricsLogger.histogram(mContext, "opt_dialog_num_failed", stats[2]);
MetricsLogger.histogram(mContext, "opt_dialog_num_total", getOptimizablePackages().size());
MetricsLogger.histogram(mContext, "opt_dialog_time_s", elapsedTimeSeconds);
}
总结：
- 如果 没有OAT升级，也不是第一次启动，也没有清理过虚拟机的缓存，那么就无需dex优化。
- 根据规则排序：
core apps > system apps > other apps - 按照排序规则，最终调用
mInstaller.dexopt()来完成 dex优化。
在PKMS中，mInstaller 才是真正安装、卸载、dex优化等操作的封装。具体是通过 Binder 调用native进程 installd 提供的接口来完成。
五、总结
- 与初始化
- 创建PKMS对象
- 注册binder服务 package
- 注册binder服务 package_native
- 第一开始阶段
- 创建 多用户服务、权限管理服务、settings等
- SystemConfig 全局系统配置
- 新建packageManager工作线程
- 第二扫描system区阶段
- 扫描 system/区域
- 区分可能要删除的包和已经更新了的包
- 第三扫描data区阶段
- 扫描data/区域
- 最终确认要删除的包和已经更新了的包
- 安装系统app
- 第四扫描结束阶段
- OAT升级逻辑处理
- 更新 package.xml
- 第五PMS的ready阶段
- dex优化
- 磁盘清理
- 通知相关对象，PMS已经初始化完成
- 等待所有安装包安装完成
