Android10_原理機制系列_PMS的啓動及應用的安裝過程
概述
這裏主要介紹 PackageManagerService(簡稱PMS)的啓動 和 一個應用的安裝過程。這裏只是大體總結，供參考，很多地方一樣須要進一步深刻了解學習的。
該篇相關代碼也是基於AndroidQ的。html
PMS也是核心服務之一，管理包相關內容，解析AndroidManifest.xml、管理應用等，最多見的是應用的安裝和卸載。
和AMS相似，PMS提供服務也是經過binder完成，也有相應的服務端和客戶端。java
PMS的幾個相關類：
IPackageManager.aidl：接口，定義了服務端和客戶端之間通訊的函數方法。
PackageManagerService：服務端。繼承IPackageManager.Stub，繼承Binder。
PackageManager：抽象類，對外的接口(可調用，SDK)。能夠經過Context#getPackageManager獲取，能夠看下下面源碼中關於PackageManager的註釋部分。
ApplicationPackageManager：客戶端。PackageManager實現類，經過內部的mPM變量參與Binder通訊。android
//PackageManager.java
/**
* Class for retrieving various kinds of information related to the application
* packages that are currently installed on the device.
*
* You can find this class through {@link Context#getPackageManager}.
*/
public abstract class PackageManager {
......
}
//ApplicationPackageManager.java
protected ApplicationPackageManager(ContextImpl context,
IPackageManager pm) {
mContext = context;
mPM = pm;
}
PMS的啓動
以前已經總結過 AMS的啓動過程 以及 應用的第一次啓動過程 ，比較詳細，關於PMS的啓動就容易理解了。
PMS啓動過程 和 AMS啓動過程 相似，都是在SystemServer啓動以後完成的，若想詳細瞭解能夠先參考AMS的啓動過程瞭解下，關於PMS的啓動這裏就大體說明下。shell
SystemServer中啓動PMS
PMS的啓動也是在SystemServer啓動以後，也屬於引導服務，在startBootstrapServices()中啓動。session
//SystemServer.java
private void startBootstrapServices() {
......
//Installer服務，真正安裝的服務，與installd交互
Installer installer = mSystemServiceManager.startService(Installer.class);
......
//標記1
mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF, mOnlyCore);
......
//標記2
mPackageManager = mSystemContext.getPackageManager();
}
private void startOtherServices() {
......
//完成dex優化
mPackageManagerService.updatePackagesIfNeeded();
......
//清理磁盤，釋放空間
mPackageManagerService.performFstrimIfNeeded();
......
//PMS準備就緒
mPackageManagerService.systemReady();
......
}
能夠看註釋大體瞭解下。
這裏主要看下標記1和標記2處，PackageManagerService.main()和mSystemContext.getPackageManager()。app
標記1：mSystemContext.getPackageManager()
先看下mSystemContext.getPackageManager()，一路看下去，就看到以下代碼。即Context#getPackageManager是建立了ApplicationPackageManager，mPM獲得賦值 IPackageManager對象，能夠經過mPm參與PMS通訊。less
//ContextImpl.java
@Override
public PackageManager getPackageManager() {
if (mPackageManager != null) {
return mPackageManager;
}
IPackageManager pm = ActivityThread.getPackageManager();
if (pm != null) {
// Doesn't matter if we make more than one instance.
return (mPackageManager = new ApplicationPackageManager(this, pm));
}
return null;
}
標記2：PackageManagerService.main():
這是真正建立PMS服務，並啓動。dom
//PackageManagerService.java
public static PackageManagerService main(Context context, Installer installer,
boolean factoryTest, boolean onlyCore) {
// Self-check for initial settings.
PackageManagerServiceCompilerMapping.checkProperties();
//初始化PMS
PackageManagerService m = new PackageManagerService(context, installer,
factoryTest, onlyCore);
m.enableSystemUserPackages();
//註冊服務 package
ServiceManager.addService("package", m);
final PackageManagerNative pmn = m.new PackageManagerNative();
//註冊服務 package_native
ServiceManager.addService("package_native", pmn);
return m;
}
這裏很簡單，主要檢查PMS環境，然建立並註冊了兩個服務package和package_native。
接下來主要看 建立PMS對象過程作了些什麼。異步
PMS的建立
PMS的構造方法很長，下面摺疊起來了，要了解能夠打開。async
代碼已摺疊，點擊顯示PMS的完整構造方法
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");
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;
mMetrics = new DisplayMetrics();
mInstaller = installer;
// Create sub-components that provide services / data. Order here is important.
synchronized (mInstallLock) {
synchronized (mPackages) {
// Expose private service for system components to use.
LocalServices.addService(
PackageManagerInternal.class, new PackageManagerInternalImpl());
sUserManager = new UserManagerService(context, this,
new UserDataPreparer(mInstaller, mInstallLock, mContext, mOnlyCore), mPackages);
mComponentResolver = new ComponentResolver(sUserManager,
LocalServices.getService(PackageManagerInternal.class),
mPackages);
mPermissionManager = PermissionManagerService.create(context,
mPackages /*externalLock*/);
mDefaultPermissionPolicy = mPermissionManager.getDefaultPermissionGrantPolicy();
mSettings = new Settings(Environment.getDataDirectory(),
mPermissionManager.getPermissionSettings(), mPackages);
}
}
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;
}
mPackageDexOptimizer = new PackageDexOptimizer(installer, mInstallLock, context,
"*dexopt*");
mDexManager = new DexManager(mContext, this, mPackageDexOptimizer, installer, mInstallLock);
mArtManagerService = new ArtManagerService(mContext, this, installer, mInstallLock);
mMoveCallbacks = new MoveCallbacks(FgThread.get().getLooper());
mViewCompiler = new ViewCompiler(mInstallLock, mInstaller);
mOnPermissionChangeListeners = new OnPermissionChangeListeners(
FgThread.get().getLooper());
getDefaultDisplayMetrics(context, mMetrics);
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "get system config");
SystemConfig systemConfig = SystemConfig.getInstance();
mAvailableFeatures = systemConfig.getAvailableFeatures();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
mProtectedPackages = new ProtectedPackages(mContext);
mApexManager = new ApexManager(context);
synchronized (mInstallLock) {
// writer
synchronized (mPackages) {
mHandlerThread = new ServiceThread(TAG,
Process.THREAD_PRIORITY_BACKGROUND, true /*allowIo*/);
mHandlerThread.start();
mHandler = new PackageHandler(mHandlerThread.getLooper());
mProcessLoggingHandler = new ProcessLoggingHandler();
Watchdog.getInstance().addThread(mHandler, WATCHDOG_TIMEOUT);
mInstantAppRegistry = new InstantAppRegistry(this);
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);
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;
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");
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
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);
}
}
if (!mOnlyCore && mFirstBoot) {
requestCopyPreoptedFiles();
}
String customResolverActivityName = Resources.getSystem().getString(
R.string.config_customResolverActivity);
if (!TextUtils.isEmpty(customResolverActivityName)) {
mCustomResolverComponentName = ComponentName.unflattenFromString(
customResolverActivityName);
}
long startTime = SystemClock.uptimeMillis();
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_SYSTEM_SCAN_START,
startTime);
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!");
}
File frameworkDir = new File(Environment.getRootDirectory(), "framework");
final VersionInfo ver = mSettings.getInternalVersion();
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
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);
}
}
}
mCacheDir = preparePackageParserCache();
// 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;
}
// 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.
scanDirTracedLI(new File(VENDOR_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR,
0);
scanDirTracedLI(new File(PRODUCT_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT,
0);
scanDirTracedLI(new File(PRODUCT_SERVICES_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES,
0);
scanDirTracedLI(new File(ODM_OVERLAY_DIR),
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_ODM,
0);
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).
scanDirTracedLI(frameworkDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_NO_DEX
| SCAN_AS_SYSTEM
| SCAN_AS_PRIVILEGED,
0);
if (!mPackages.containsKey("android")) {
throw new IllegalStateException(
"Failed to load frameworks package; check log for warnings");
}
// Collect privileged system packages.
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.
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
}
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
}
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");
try {
privilegedOdmAppDir = privilegedOdmAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(privilegedOdmAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR
| SCAN_AS_PRIVILEGED,
0);
// Collect ordinary odm packages. /odm is another vendor partition
// other than /vendor.
File odmAppDir = new File(Environment.getOdmDirectory(), "app");
try {
odmAppDir = odmAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(odmAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_VENDOR,
0);
// Collect all OEM packages.
final File oemAppDir = new File(Environment.getOemDirectory(), "app");
scanDirTracedLI(oemAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_OEM,
0);
// Collected privileged /product packages.
File privilegedProductAppDir = new File(Environment.getProductDirectory(), "priv-app");
try {
privilegedProductAppDir = privilegedProductAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(privilegedProductAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT
| SCAN_AS_PRIVILEGED,
0);
// Collect ordinary /product packages.
File productAppDir = new File(Environment.getProductDirectory(), "app");
try {
productAppDir = productAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(productAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT,
0);
// Collected privileged /product_services packages.
File privilegedProductServicesAppDir =
new File(Environment.getProductServicesDirectory(), "priv-app");
try {
privilegedProductServicesAppDir =
privilegedProductServicesAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(privilegedProductServicesAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES
| SCAN_AS_PRIVILEGED,
0);
// Collect ordinary /product_services packages.
File productServicesAppDir = new File(Environment.getProductServicesDirectory(), "app");
try {
productServicesAppDir = productServicesAppDir.getCanonicalFile();
} catch (IOException e) {
// failed to look up canonical path, continue with original one
}
scanDirTracedLI(productServicesAppDir,
mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanFlags
| SCAN_AS_SYSTEM
| SCAN_AS_PRODUCT_SERVICES,
0);
// Prune any system packages that no longer exist.
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<>();
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)) {
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);
mExpectingBetter.put(ps.name, ps.codePath);
}
continue;
}
if (!mSettings.isDisabledSystemPackageLPr(ps.name)) {
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 {
// 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) {
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.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);
}
if (!mOnlyCore) {
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START,
SystemClock.uptimeMillis());
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.
for (int i = possiblyDeletedUpdatedSystemApps.size() - 1; i >= 0; --i) {
final String packageName = possiblyDeletedUpdatedSystemApps.get(i);
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
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
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
removePackageLI(pkg, true);
try {
final File codePath = new File(pkg.applicationInfo.getCodePath());
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.
*/
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");
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;
}
mSettings.enableSystemPackageLPw(packageName);
try {
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.
// 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);
}
}
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 = getSetupWizardPackageName();
mComponentResolver.fixProtectedFilterPriorities();
mSystemTextClassifierPackage = getSystemTextClassifierPackageName();
mWellbeingPackage = getWellbeingPackageName();
mDocumenterPackage = getDocumenterPackageName();
mConfiguratorPackage = getDeviceConfiguratorPackageName();
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));
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();
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.
final boolean sdkUpdated = (ver.sdkVersion != mSdkVersion);
if (sdkUpdated) {
Slog.i(TAG, "Platform changed from " + ver.sdkVersion + " to "
+ mSdkVersion + "; regranting permissions for internal storage");
}
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.
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");
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");
mSettings.writeLPr();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
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);
}
}
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());
}
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");
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);
}
從構造方法中的EventLogTags的標記，大體分爲5個階段，根據這個大體瞭解下。
- BOOT_PROGRESS_PMS_START
建立和保存須要使用的相關對象，下面列出一些比較重要的：
- mInstaller：Installer對象，系統服務，與installd交互，管理包的安裝、卸載、數據、遷移等。
- sUserManager：UserManagerService，用戶管理服務。
- mPermissionManager：PermissionManagerServiceInternal，權限管理相關。
- mSettings：Settings，保存動態設置信息。這裏經過addSharedUserLPw設置shared uid到Settings中(有8種：system、phone、log、nfc、bluetooth、shell、se、networkstack)。這裏的Settings是frameworks/base/services/core/java/com/android/server/pm/Settings.java而不是frameworks/base/core/java/android/provider/Settings.java下的。
- mPackageDexOptimizer：PackageDexOptimizer，助手工具類，進行dex優化等，dexopt。
- mDexManager：DexManager，dex管理類，跟蹤dex文件的使用等。
- SystemConfig：用於獲取系統的全局配置信息。
- mApexManager：ApexManager，apex管理類，處理與apex服務通訊。
-
BOOT_PROGRESS_PMS_SYSTEM_SCAN_START
掃描系統目錄中的app等，經過scanDirTracedLI()方法。
這個階段主要掃描的路徑是：/vendor/overlay；/product/overlay；/product_services/overlay；/odm/overlay；/oem/overlay；/system/framework；/system/priv-app；/system/app；/vendor/priv-app；/vendor/app；/odm/priv-app；/odm/app；/oem/app；/product/priv-app；/product/app；/product_services/priv-app；/product_services/app；
歸納起來，就是vendor/product/product_services/odm/oem下的overlay目錄；/system/framework/;system/vendor/odm/oem/product/product_services下的priv-app和app目錄(沒有/oem/priv-app)。 -
BOOT_PROGRESS_PMS_DATA_SCAN_START
掃描非系統目錄app等。
這個階段主要掃描目錄：/data/app； -
BOOT_PROGRESS_PMS_SCAN_END
掃描完成，將結果寫入文件中。
經過mSettings.writeLPr();方法。寫入到文件：/data/system/packages.xml和/data/system/packages.list。
安裝、卸載等都會更新這個目錄。 -
BOOT_PROGRESS_PMS_READY
PMS準備完成，建立PackageInstallerService服務。mInstallerService = new PackageInstallerService(context, this, mApexManager);。
題外話：
apex是 AndroidQ開始提出的mainline計劃後 而有的一種新格式，google將framework也分紅一個個小模塊，最終但願經過play store對system的核心內容的進行更新，不須要odm、oem干預。而這一個個模塊與apk應用不一樣，所以有了apex這種格式。其實google在Android O開始就再弄的Treble計劃，一步步將system與vendor分開了獨立，最終整個系統能夠直接使用一套公共的system.img即GSI(Generic System Image)。在Android R開始，kernel部分也開始使用這套，弄一套通用內核鏡像GKI(Generic Kernel Image)。 Android各個版本之間變更是很是大的，可能用戶感覺不到。爲了實現這些，引入了不少新的概念和技術。
/data/system/packages.xml，在 Android調試很是有用的命令集 總結中也提到過，這裏就是該文件內容是什麼，怎麼來的。
因此預置應用越多，掃描時間會越長，影響開機時間。
一個應用的安裝
應用的安裝，最多見的是點擊apk後的有界面的安裝 和 開發中經過adb命令的靜默安裝。
下面關於這兩種安裝方式，簡單說明下。
點擊安裝(有界面)
1.點擊安裝，PackageInstaller.apk處理過程
這個過程經過系統預置的PackageInstaller.apk或相似應用完成。
點擊apk，進行一些驗證後跳轉到了PackageInstallerActivity，即彈出的」是否安裝此應用「的確認安裝界面。點擊確認安裝後，進入了InstallInstalling。
點擊apk進行安裝，PackageInstaller.apk是從InstallStart->PackageInstallerActivity->InstallInstalling。
注：這裏以aosp中的PackageInstaller.apk說明(com.android.packageinstaller)，在外單中 通常預置的是GMS包中的GooglePackageInstaller。
下面是大體的代碼過程的關鍵代碼：
//InstallStart.java
protected void onCreate(@Nullable Bundle savedInstanceState) {
Intent nextActivity = new Intent(intent);
.....
if (isSessionInstall) {
nextActivity.setClass(this, PackageInstallerActivity.class);
}
......
if (nextActivity != null) {
startActivity(nextActivity);
}
}
//PackageInstallerActivity.java
protected void onCreate(Bundle icicle) {
.......
bindUi();
}
private void bindUi() {
......
mAlert.setButton(DialogInterface.BUTTON_POSITIVE, getString(R.string.install),
(ignored, ignored2) -> {
if (mOk.isEnabled()) {
if (mSessionId != -1) {
mInstaller.setPermissionsResult(mSessionId, true);
finish();
} else {
startInstall();
}
}
}, null);
......
}
private void startInstall() {
Intent newIntent = new Intent();
newIntent.putExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO,
mPkgInfo.applicationInfo);
newIntent.setData(mPackageURI);
newIntent.setClass(this, InstallInstalling.class);
......
startActivity(newIntent);
finish();
}
能夠清晰看到，點擊確認安裝後，經過startInstall()方法進入了InstallInstalling。
接着看InstallInstalling的處理：
//InstallInstalling.java
protected void onCreate(@Nullable Bundle savedInstanceState) {
......
mPackageURI = getIntent().getData();
if ("package".equals(mPackageURI.getScheme())) {
.......
} else {
......
if (savedInstanceState != null) {
......
} else {
......
try {
mInstallId = InstallEventReceiver
.addObserver(this, EventResultPersister.GENERATE_NEW_ID,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
try {
mSessionId = getPackageManager().getPackageInstaller().createSession(params);
} catch (IOException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
}
mCancelButton = mAlert.getButton(DialogInterface.BUTTON_NEGATIVE);
mSessionCallback = new InstallSessionCallback();
}
}
@Override
protected void onResume() {
super.onResume();
// This is the first onResume in a single life of the activity
if (mInstallingTask == null) {
PackageInstaller installer = getPackageManager().getPackageInstaller();
PackageInstaller.SessionInfo sessionInfo = installer.getSessionInfo(mSessionId);
if (sessionInfo != null && !sessionInfo.isActive()) {
mInstallingTask = new InstallingAsyncTask();
mInstallingTask.execute();
} else {
// we will receive a broadcast when the install is finished
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
}
}
}
onCreate()中建立了一個安裝會話並返回得到一個sessionId。onResume()中進行進一步安裝。
2.建立安裝的會話
先看onCreate()中建立安裝會話，返回的sessionId很重要。
InstallEventReceiver是一個BroadcastReceiver，接收安裝事件並回調給EventResultPersister。mSessionId是安裝的會話id。
添加log能夠看到，mPackageURI.getScheme()的值是"file"。最後關鍵執行到的是getPackageManager().getPackageInstaller().createSession(params)這句。
getPackageManager()獲取PM對象，而後調用實現類ApplicationPackageManager中getPackageInstaller()獲得的是PackageInstaller對象。最終調用的是PackageInstaller中的createSession()建立安裝會話並返回sessionId。這裏不列出代碼，直接看createSession()方法。
//PackageInstaller.java
//frameworks/base/core/java/android/content/pm/PackageInstaller.java
private final IPackageInstaller mInstaller;
public int createSession(@NonNull SessionParams params) throws IOException {
try {
final String installerPackage;
......
return mInstaller.createSession(params, installerPackage, mUserId);
}
......
}
注意，這裏調用的是mInstaller.createSession()。mInstaller是IPackageInstaller，一看就知道這也是經過binder調用的一個服務，這個服務是PackageInstallerService，即最終調用的是PackageInstallerService的createSession()方法建立了一個安裝會話 並 返回了sessionId。
這裏不細述建立安裝會話的過程了。
3.安裝會話建立後，進一步安裝
接着看onResume()。這裏主要是看mInstallingTask.execute()。
/**
* Send the package to the package installer and then register a event result observer that
* will call {@link #launchFinishBasedOnResult(int, int, String)}
*/
private final class InstallingAsyncTask extends AsyncTask<Void, Void,
PackageInstaller.Session> {
volatile boolean isDone;
@Override
protected PackageInstaller.Session doInBackground(Void... params) {
PackageInstaller.Session session;
try {
session = getPackageManager().getPackageInstaller().openSession(mSessionId);
} catch (IOException e) {
return null;
}
session.setStagingProgress(0);
try {
File file = new File(mPackageURI.getPath());
try (InputStream in = new FileInputStream(file)) {
long sizeBytes = file.length();
try (OutputStream out = session
.openWrite("PackageInstaller", 0, sizeBytes)) {
byte[] buffer = new byte[1024 * 1024];
while (true) {
int numRead = in.read(buffer);
if (numRead == -1) {
session.fsync(out);
break;
}
if (isCancelled()) {
session.close();
break;
}
out.write(buffer, 0, numRead);
if (sizeBytes > 0) {
float fraction = ((float) numRead / (float) sizeBytes);
session.addProgress(fraction);
}
}
}
}
return session;
} catch (IOException | SecurityException e) {
Log.e(LOG_TAG, "Could not write package", e);
session.close();
return null;
} finally {
synchronized (this) {
isDone = true;
notifyAll();
}
}
}
@Override
protected void onPostExecute(PackageInstaller.Session session) {
if (session != null) {
Intent broadcastIntent = new Intent(BROADCAST_ACTION);
broadcastIntent.setFlags(Intent.FLAG_RECEIVER_FOREGROUND);
broadcastIntent.setPackage(getPackageName());
broadcastIntent.putExtra(EventResultPersister.EXTRA_ID, mInstallId);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
InstallInstalling.this,
mInstallId,
broadcastIntent,
PendingIntent.FLAG_UPDATE_CURRENT);
session.commit(pendingIntent.getIntentSender());
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
} else {
getPackageManager().getPackageInstaller().abandonSession(mSessionId);
if (!isCancelled()) {
launchFailure(PackageManager.INSTALL_FAILED_INVALID_APK, null);
}
}
}
}
InstallingAsyncTask是個異步任務。
doInBackground中，apk的信息(經過URI獲取)經過IO流寫入到PackageInstaller.Session中。在onPostExecute中，經過session.commit()發送安裝。
Session就是經過sessionId獲取打開的。
接下來主要看發送安裝。
PackageInstaller.Session.commit()發送安裝
//frameworks/base/core/java/android/content/pm/PackageInstaller.java
public static class Session implements Closeable {
protected final IPackageInstallerSession mSession;
public void commit(@NonNull IntentSender statusReceiver) {
try {
mSession.commit(statusReceiver, false);
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
}
//PackageInstallerSession.java
public class PackageInstallerSession extends IPackageInstallerSession.Stub {
@Override
public void commit(@NonNull IntentSender statusReceiver, boolean forTransfer) {
......
if (!markAsCommitted(statusReceiver, forTransfer)) {
return;
}
if (isMultiPackage()) {
final SparseIntArray remainingSessions = mChildSessionIds.clone();
final IntentSender childIntentSender =
new ChildStatusIntentReceiver(remainingSessions, statusReceiver)
.getIntentSender();
RuntimeException commitException = null;
boolean commitFailed = false;
for (int i = mChildSessionIds.size() - 1; i >= 0; --i) {
final int childSessionId = mChildSessionIds.keyAt(i);
try {
// commit all children, regardless if any of them fail; we'll throw/return
// as appropriate once all children have been processed
if (!mSessionProvider.getSession(childSessionId)
.markAsCommitted(childIntentSender, forTransfer)) {
commitFailed = true;
}
} catch (RuntimeException e) {
commitException = e;
}
}
if (commitException != null) {
throw commitException;
}
if (commitFailed) {
return;
}
}
mHandler.obtainMessage(MSG_COMMIT).sendToTarget();
}
}
最終調用到PackageInstallerSession中的commit()。主要看mHandler.obtainMessage(MSG_COMMIT).sendToTarget(); ，即經過Handler發送了MSG_COMMIT的消息，進程間通訊。
接着看消息處理代碼：
//PackageInstallerSession.java
private final Handler.Callback mHandlerCallback = new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case MSG_COMMIT:
handleCommit();
break;
......
}
return true;
}
};
private void handleCommit() {
......
// For a multiPackage session, read the child sessions
// outside of the lock, because reading the child
// sessions with the lock held could lead to deadlock
// (b/123391593).
List<PackageInstallerSession> childSessions = getChildSessions();
try {
synchronized (mLock) {
commitNonStagedLocked(childSessions);
}
} catch (PackageManagerException e) {
......
}
}
@GuardedBy("mLock")
private void commitNonStagedLocked(List<PackageInstallerSession> childSessions)
throws PackageManagerException {
final PackageManagerService.ActiveInstallSession committingSession =
makeSessionActiveLocked();
if (committingSession == null) {
return;
}
if (isMultiPackage()) {
List<PackageManagerService.ActiveInstallSession> activeChildSessions =
new ArrayList<>(childSessions.size());
boolean success = true;
PackageManagerException failure = null;
for (int i = 0; i < childSessions.size(); ++i) {
final PackageInstallerSession session = childSessions.get(i);
try {
final PackageManagerService.ActiveInstallSession activeSession =
session.makeSessionActiveLocked();
if (activeSession != null) {
activeChildSessions.add(activeSession);
}
} catch (PackageManagerException e) {
failure = e;
success = false;
}
}
if (!success) {
try {
mRemoteObserver.onPackageInstalled(
null, failure.error, failure.getLocalizedMessage(), null);
} catch (RemoteException ignored) {
}
return;
}
mPm.installStage(activeChildSessions);
} else {
mPm.installStage(committingSession);
}
}
很清晰，最終經過mPm.installStage() 進入PMS進行處理。
4.安裝進入PMS
直接看PMS的installStage()。
//PackageManagerService.java
void installStage(ActiveInstallSession activeInstallSession) {
if (DEBUG_INSTANT) {
if ((activeInstallSession.getSessionParams().installFlags
& PackageManager.INSTALL_INSTANT_APP) != 0) {
Slog.d(TAG, "Ephemeral install of " + activeInstallSession.getPackageName());
}
}
final Message msg = mHandler.obtainMessage(INIT_COPY);
final InstallParams params = new InstallParams(activeInstallSession);
params.setTraceMethod("installStage").setTraceCookie(System.identityHashCode(params));
msg.obj = params;
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "installStage",
System.identityHashCode(msg.obj));
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "queueInstall",
System.identityHashCode(msg.obj));
mHandler.sendMessage(msg);
}
class PackageHandler extends Handler {
void doHandleMessage(Message msg) {
switch (msg.what) {
case INIT_COPY: {
HandlerParams params = (HandlerParams) msg.obj;
if (params != null) {
if (DEBUG_INSTALL) Slog.i(TAG, "init_copy: " + params);
Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, "queueInstall",
System.identityHashCode(params));
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "startCopy");
params.startCopy();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
break;
}
......
}
}
}
經過Handler發送了INIT_COPY消息，開始拷貝apk到執行地方進行進一步安裝。
5.拷貝APK
看startCopy():
//PackageManagerService.java
private abstract class HandlerParams {
final void startCopy() {
if (DEBUG_INSTALL) Slog.i(TAG, "startCopy " + mUser + ": " + this);
handleStartCopy();
handleReturnCode();
}
abstract void handleStartCopy();
abstract void handleReturnCode();
}
class InstallParams extends HandlerParams {
@Override
public void handleStartCopy() {
int ret = PackageManager.INSTALL_SUCCEEDED;
// If we're already staged, we've firmly committed to an install location
......
/*
* If we have too little free space, try to free cache
* before giving up.
*/
......
if (ret == PackageManager.INSTALL_SUCCEEDED) {
int loc = pkgLite.recommendedInstallLocation;
if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION) {
ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION;
} else if (loc == PackageHelper.RECOMMEND_FAILED_ALREADY_EXISTS) {
ret = PackageManager.INSTALL_FAILED_ALREADY_EXISTS;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
ret = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_APK) {
ret = PackageManager.INSTALL_FAILED_INVALID_APK;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_URI) {
ret = PackageManager.INSTALL_FAILED_INVALID_URI;
} else if (loc == PackageHelper.RECOMMEND_MEDIA_UNAVAILABLE) {
ret = PackageManager.INSTALL_FAILED_MEDIA_UNAVAILABLE;
} else {
// Override with defaults if needed.
......
}
}
final InstallArgs args = createInstallArgs(this);
mVerificationCompleted = true;
mEnableRollbackCompleted = true;
Args = args;
......
mRet = ret;
}
@Override
void handleReturnCode() {
if (mVerificationCompleted && mEnableRollbackCompleted) {
......
if (mRet == PackageManager.INSTALL_SUCCEEDED) {
mRet = mArgs.copyApk();
}
processPendingInstall(mArgs, mRet);
}
}
}
startCopy()只有兩個方法，handleStartCopy()和handleReturnCode()。
handleStartCopy()中進行安裝前的各類驗證，檢查文件、空間、發送給全部sufficientVerifiers進行驗證。 驗證成功，即mRet == PackageManager.INSTALL_SUCCEEDED，在handleReturnCode()中進行apk拷貝工做。
拷貝apk目標路徑
接着看下handleReturnCode()中的拷貝apk操做：mArgs.copyApk()。
mArgs這裏是FileInstallArgs。
//PackageManagerService.java
private InstallArgs createInstallArgs(InstallParams params) {
if (params.move != null) {
return new MoveInstallArgs(params);
} else {
return new FileInstallArgs(params);
}
}
//PackageManagerService.java
class FileInstallArgs extends InstallArgs {
int copyApk() {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "copyApk");
try {
return doCopyApk();
} finally {
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
}
private int doCopyApk() {
......
final boolean isEphemeral = (installFlags & PackageManager.INSTALL_INSTANT_APP) != 0;
final File tempDir =
mInstallerService.allocateStageDirLegacy(volumeUuid, isEphemeral);
codeFile = tempDir;
resourceFile = tempDir;
......
int ret = PackageManagerServiceUtils.copyPackage(
origin.file.getAbsolutePath(), codeFile);
......
return ret;
}
}
//PackageManagerServiceUtils.java
public static int copyPackage(String packagePath, File targetDir) {
if (packagePath == null) {
return PackageManager.INSTALL_FAILED_INVALID_URI;
}
try {
final File packageFile = new File(packagePath);
final PackageParser.PackageLite pkg = PackageParser.parsePackageLite(packageFile, 0);
copyFile(pkg.baseCodePath, targetDir, "base.apk");
if (!ArrayUtils.isEmpty(pkg.splitNames)) {
for (int i = 0; i < pkg.splitNames.length; i++) {
copyFile(pkg.splitCodePaths[i], targetDir,
"split_" + pkg.splitNames[i] + ".apk");
}
}
return PackageManager.INSTALL_SUCCEEDED;
} catch (PackageParserException | IOException | ErrnoException e) {
Slog.w(TAG, "Failed to copy package at " + packagePath + ": " + e);
return PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
}
}
拷貝到的目標文件是：/data/app/vmdl[sessionId].tmp/base.apk。如果多個，/data/app/vmdl[sessionId].tmp/split_[pkgname].apk。
例如：如個人一次安裝 /data/app/vmdl1101585668.tmp/base.apk，此次安裝的sessionId是1101585668。
注：用userdebug軟件，安裝抓取的log也能看出大體安裝過程的信息，能夠輔助。如搜索TAG爲 PackageManager(PMS類的TAG)。
下面是路徑相關代碼：
//PackageInstallerService.java
public File allocateStageDirLegacy(String volumeUuid, boolean isEphemeral) throws IOException {
synchronized (mSessions) {
......
final File sessionStageDir = buildTmpSessionDir(sessionId, volumeUuid);
......
}
}
private File buildTmpSessionDir(int sessionId, String volumeUuid) {
final File sessionStagingDir = getTmpSessionDir(volumeUuid);
return new File(sessionStagingDir, "vmdl" + sessionId + ".tmp");
}
private File getTmpSessionDir(String volumeUuid) {
return Environment.getDataAppDirectory(volumeUuid);
}
6.真正安裝
copyFile完成拷貝後，回頭看handleReturnCode()，mArgs.copyApk();後執行processPendingInstall(mArgs, mRet);開始真正的安裝。
//PackageManagerService.java
private void processPendingInstall(final InstallArgs args, final int currentStatus) {
if (args.mMultiPackageInstallParams != null) {
args.mMultiPackageInstallParams.tryProcessInstallRequest(args, currentStatus);
} else {
//安裝參數
PackageInstalledInfo res = createPackageInstalledInfo(currentStatus);
processInstallRequestsAsync(
res.returnCode == PackageManager.INSTALL_SUCCEEDED,
Collections.singletonList(new InstallRequest(args, res)));
}
}
// Queue up an async operation since the package installation may take a little while.
private void processInstallRequestsAsync(boolean success,
List<InstallRequest> installRequests) {
mHandler.post(() -> {
if (success) {
for (InstallRequest request : installRequests) {
//若是以前安裝失敗，清理無用信息
request.args.doPreInstall(request.installResult.returnCode);
}
synchronized (mInstallLock) {
//進行安裝
installPackagesTracedLI(installRequests);
}
for (InstallRequest request : installRequests) {
//安裝失敗，清理無用信息
request.args.doPostInstall(
request.installResult.returnCode, request.installResult.uid);
}
}
for (InstallRequest request : installRequests) {
restoreAndPostInstall(request.args.user.getIdentifier(), request.installResult,
new PostInstallData(request.args, request.installResult, null));
}
});
}
private PackageInstalledInfo createPackageInstalledInfo(
int currentStatus) {
PackageInstalledInfo res = new PackageInstalledInfo();
res.setReturnCode(currentStatus);
res.uid = -1;
res.pkg = null;
res.removedInfo = null;
return res;
}
看上述註釋大體瞭解下，咱們接着看installPackagesTracedLI()。
//PMS
@GuardedBy({"mInstallLock", "mPackages"})
private void installPackagesTracedLI(List<InstallRequest> requests) {
try {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "installPackages");
installPackagesLI(requests);
} finally {
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
}
private void installPackagesLI(List<InstallRequest> requests) {
......
try {
for (InstallRequest request : requests) {
// TODO(b/109941548): remove this once we've pulled everything from it and into
// scan, reconcile or commit.
final PrepareResult prepareResult;
try {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "preparePackage");
//分析安裝狀態、分析包並檢查驗證
//檢查包並分析完整性；檢查SDK版本、靜態庫等；檢查簽名；設置權限；
prepareResult = preparePackageLI(request.args, request.installResult);
}
......
try {
//掃描apk
final List<ScanResult> scanResults = scanPackageTracedLI(
prepareResult.packageToScan, prepareResult.parseFlags,
prepareResult.scanFlags, System.currentTimeMillis(),
request.args.user);
}
......
}
executePostCommitSteps(commitRequest);
} finally {
......
}
}
installPackagesLI()方法很複雜，這裏也不細述了。
installPackagesLI()對安裝包自己以及安裝環境等進行一些相關的檢查驗證。檢查包的完整性、SDK版本、簽名、共享庫、設置權限等等，檢查安裝環境是否知足等。能夠大體看下方法中這幾個方法：
prepareResult = preparePackageLI(request.args, request.installResult);
final List<ScanResult> scanResults = scanPackageTracedLI(
prepareResult.packageToScan, prepareResult.parseFlags,
prepareResult.scanFlags, System.currentTimeMillis(),
request.args.user);
ReconcileRequest reconcileRequest = new ReconcileRequest(preparedScans, installArgs,
最後執行executePostCommitSteps()進一步進行安裝，最終經過binder進入installd進程完成安裝。這個過程也很複雜，本人也需進一步閱讀。executePostCommitSteps()後續簡單參考過程：
PackageManagerService.java installPackagesLI()->executePostCommitSteps()->prepareAppDataAfterInstallLIF()->prepareAppDataLIF()->prepareAppDataLeafLIF()->mInstaller.createAppData()。 Installer.java： createAppData()->mInstalld.createAppData()。
關於過程當中一些路徑操做多說一點：
在preparePackageLI()中有個rename的過程，將前面拷貝的文件目錄重命名了下，因此安裝後能在手機中看到的是重命名後的目錄。
重命名規則：/data/app/[packagename]-[suffix]。
例如個人安裝：PackageManager: Renaming /data/app/vmdl1101585668.tmp to /data/app/[packagename]-RDISkz-0p77Yh-pAwNtfFA==
相關代碼：
private PrepareResult preparePackageLI(InstallArgs args, PackageInstalledInfo res)
......
if (!args.doRename(res.returnCode, pkg)) {
throw new PrepareFailure(INSTALL_FAILED_INSUFFICIENT_STORAGE, "Failed rename");
}
......
}
class FileInstallArgs extends InstallArgs {
boolean doRename(int status, PackageParser.Package pkg) {
.....
final File targetDir = codeFile.getParentFile();
final File beforeCodeFile = codeFile;
final File afterCodeFile = getNextCodePath(targetDir, pkg.packageName);
if (DEBUG_INSTALL) Slog.d(TAG, "Renaming " + beforeCodeFile + " to " + afterCodeFile);
.....
Os.rename(beforeCodeFile.getAbsolutePath(), afterCodeFile.getAbsolutePath());
.....
}
}
private File getNextCodePath(File targetDir, String packageName) {
File result;
SecureRandom random = new SecureRandom();
byte[] bytes = new byte[16];
do {
random.nextBytes(bytes);
String suffix = Base64.encodeToString(bytes, Base64.URL_SAFE | Base64.NO_WRAP);
result = new File(targetDir, packageName + "-" + suffix);
} while (result.exists());
return result;
}
一點總結
點擊安裝，經過相似PackageInstaller.apk處理。
確認安裝後，拷貝apk到/data/app/vmdl[sessionId].tmp/base.apk下。
進一步安裝中，重命名路徑爲 /data/app/[packagename]-[suffix]。
如個人安裝：拷貝到/data/app/vmdl1101585668.tmp/base.apk。重命名後是：/data/app/[packagename]-RDISkz-0p77Yh-pAwNtfFA==。
查看/data/app/[packagename]-RDISkz-0p77Yh-pAwNtfFA==目錄，有base.apk lib/ oat/，安裝後的apk、庫、odex、vdex都在這個目錄下。
系統預置的還在預置目錄下，如/system/priv-app。
/data/data/[packagename]存放應用數據，通常有cache code_cache lib。
adb安裝(無界面 靜默安裝)
這也是一個簡單參考，不完整。
使用adb命令進行安裝，下面大體能夠參考：
//system/core/adb/client/commandline.cpp
int adb_commandline(int argc, const char** argv) {
......
else if (!strcmp(argv[0], "install")) {
if (argc < 2) error_exit("install requires an argument");
return install_app(argc, argv);
}
......
}
//system/core/adb/client/adb_install.cpp
int install_app(int argc, const char** argv) {
......
switch (installMode) {
case INSTALL_PUSH:
return install_app_legacy(passthrough_argv.size(), passthrough_argv.data(),
use_fastdeploy, use_localagent);
case INSTALL_STREAM:
return install_app_streamed(passthrough_argv.size(), passthrough_argv.data(),
use_fastdeploy, use_localagent);
case INSTALL_DEFAULT:
default:
return 1;
}
}
static int install_app_legacy(int argc, const char** argv, bool use_fastdeploy,
bool use_localagent) {
......
result = pm_command(argc, argv);
......
}
static int pm_command(int argc, const char** argv) {
std::string cmd = "pm";
while (argc-- > 0) {
cmd += " " + escape_arg(*argv++);
}
return send_shell_command(cmd);
}
在AndroidO時，還有源碼frameworks/base/cmds/pm/src/com/android/commands/pm/Pm.java。AndroidO最終Pm.java執行mInstaller.createSession()進入PMS。
AndroidQ中，frameworks/base/cmds/pm/src/com/android/commands/pm只有一個Andoird.mk了，pm是system/bin下的一個可執行文件了system/bin/pm。 不過應該是和O相似的(AndoridP中也沒有Pm.java的源碼了)，最終也是進入的PMS中方法，迴歸到相似點擊安裝的過程。 咱們能夠在上面點擊安裝過程當中的PMS方法中添加調用棧或log等，瞭解adb安裝的過程是 進入的哪，進一步跟蹤瞭解。
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