1.PackageManagerService的初始化在SystemServer中進(jìn)行
// Start the package manager.
traceBeginAndSlog("StartPackageManagerService");
mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF, mOnlyCore);
mFirstBoot = mPackageManagerService.isFirstBoot();
mPackageManager = mSystemContext.getPackageManager();
Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
2.PackageManagerService.main(Context c, Installer i,boolean factoryTest, boolean onlyCore)
public static PackageManagerService main(Context context, Installer installer,
boolean factoryTest, boolean onlyCore) {
PackageManagerService m = new PackageManagerService(context, installer,
factoryTest, onlyCore);
ServiceManager.addService("package", m);
return m;
}
3.PackageManagerService構(gòu)造函數(shù)超級長，這里一個(gè)點(diǎn)一個(gè)點(diǎn)粗略來過一下
3.1首先是Setting的相關(guān)信息處理
// 存儲系統(tǒng)運(yùn)行過程中的一些設(shè)置信息
mSettings = new Settings(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);
3.2 Setting構(gòu)造函數(shù):主要是一些文件初始化工作
Settings(Object lock) {
// Environment.getDataDirectory() : /data
this(Environment.getDataDirectory(), lock);
}
Settings(File dataDir, Object lock) {
mLock = lock;
mRuntimePermissionsPersistence = new RuntimePermissionPersistence(mLock);
mSystemDir = new File(dataDir, "system");// /data/system
mSystemDir.mkdirs();
FileUtils.setPermissions(mSystemDir.toString(),
FileUtils.S_IRWXU|FileUtils.S_IRWXG
|FileUtils.S_IROTH|FileUtils.S_IXOTH,
-1, -1);
// /data/system/packages.xml
mSettingsFilename = new File(mSystemDir, "packages.xml");
// /data/system/packages-backup.xml
mBackupSettingsFilename = new File(mSystemDir, "packages-backup.xml");
// /data/system/packages.list
mPackageListFilename = new File(mSystemDir, "packages.list");
FileUtils.setPermissions(mPackageListFilename, 0640, SYSTEM_UID, PACKAGE_INFO_GID);
// Deprecated: Needed for migration
mStoppedPackagesFilename = new File(mSystemDir, "packages-stopped.xml");
mBackupStoppedPackagesFilename = new File(mSystemDir, "packages-stopped-backup.xml");
}
3.3 Settings.addSharedUserLPw()
/**
* name = "android.uid.system",
* uid = Process.SYSTEM_UID(1000),
* pkgFlags = ApplicationInfo.FLAG_SYSTEM ,表示該應(yīng)用安裝在系統(tǒng)進(jìn)程中，屬于系統(tǒng)應(yīng)用
* pkgPrivateFlags = ApplicationInfo.PRIVATE_FLAG_PRIVILEGED
*/
SharedUserSetting addSharedUserLPw(String name, int uid, int pkgFlags, int pkgPrivateFlags) {
// mSharedUsers:ArrayMap<String, SharedUserSetting> 是一個(gè)Map,key值為uid字符竄描述，value為SharedUserSetting
SharedUserSetting s = mSharedUsers.get(name);
if (s != null) {// 從Map中直接取出來
if (s.userId == uid) {
return s;
}
PackageManagerService.reportSettingsProblem(Log.ERROR,
"Adding duplicate shared user, keeping first: " + name);
return null;
}
// Map中沒有，生成一個(gè)
s = new SharedUserSetting(name, pkgFlags, pkgPrivateFlags);
s.userId = uid;
if (addUserIdLPw(uid, s, name)) {
mSharedUsers.put(name, s);
return s;
}
return null;
}
private boolean addUserIdLPw(int uid, Object obj, Object name) {
if (uid > Process.LAST_APPLICATION_UID) {// uid > 19999
return false;
}
if (uid >= Process.FIRST_APPLICATION_UID) {// uid >= 10000 && uid <= 19999-->普通APK所在的進(jìn)程UID
int N = mUserIds.size();
final int index = uid - Process.FIRST_APPLICATION_UID;
while (index >= N) {
mUserIds.add(null);
N++;
}
if (mUserIds.get(index) != null) {
PackageManagerService.reportSettingsProblem(Log.ERROR,
"Adding duplicate user id: " + uid
+ " name=" + name);
return false;
}
mUserIds.set(index, obj);
} else { // uid < 10000 && uid > 0-->系統(tǒng)APK所在的進(jìn)程UID
if (mOtherUserIds.get(uid) != null) {
PackageManagerService.reportSettingsProblem(Log.ERROR,
"Adding duplicate shared id: " + uid
+ " name=" + name);
return false;
}
mOtherUserIds.put(uid, obj);
}
return true;
}
相關(guān)類圖：
QQ截圖20160805164615.png
上面這些到底在設(shè)置些啥信息呢？這個(gè)要從AndroidManifest.xml的<manifest>標(biāo)簽的android:sharedUserId配置說起，如果多個(gè)APK設(shè)置的android:sharedUserId都是一樣的話，那這些APK則具有相同的權(quán)限，可共享彼此的數(shù)據(jù)，并且可運(yùn)行在同一個(gè)進(jìn)程當(dāng)中(<application>標(biāo)簽配置android:process為一樣即可)；
SharedUserSetting這個(gè)類是用來保存共享數(shù)據(jù)的，其中的name屬性保存的就是sharedUserId指定的字符竄也就是共享用戶名，userId屬性存儲的是共享用戶UID，packages保存的就是sharedUserId配置為一樣的所有的APK信息。PackageSetting對應(yīng)的是其中某個(gè)APK相關(guān)信息。
Android系統(tǒng)中的UID，是用戶ID的縮寫，一般而言，每個(gè)進(jìn)程都會有一個(gè)UID，表示該進(jìn)程屬于哪個(gè)用戶，不同的用戶具有不同的權(quán)限，一個(gè)進(jìn)程也可以分屬不同的用戶組，表示每個(gè)用戶組具有相應(yīng)的權(quán)限。
這個(gè)怎么理解，拿Android來說，它分為系統(tǒng)進(jìn)程和應(yīng)用進(jìn)程，系統(tǒng)進(jìn)程對應(yīng)一個(gè)UID，某個(gè)應(yīng)用進(jìn)程對應(yīng)另外一個(gè)UID，系統(tǒng)進(jìn)程具有它自己的權(quán)限，應(yīng)用進(jìn)程對應(yīng)的也有它自己相應(yīng)的權(quán)限；對于系統(tǒng)進(jìn)程或是某個(gè)應(yīng)用進(jìn)程來說，它屬于本進(jìn)程的用戶組，它也可以屬于其他進(jìn)程中的某個(gè)用戶組(sharedUserId)，比如framework-res.apk和SettingsProvider，它們都運(yùn)行在"system"進(jìn)程當(dāng)中，它們的android:sharedUserId都是"android.uid.system",這就意味著它們不但具有獲取它們各自本身的數(shù)據(jù)的權(quán)限，還具有獲取彼此共享數(shù)據(jù)的權(quán)限。假如還有某個(gè)APK設(shè)置的process也為system，但是沒有設(shè)置android:sharedUserId，那么它具有的權(quán)限就是只能訪問它自己的數(shù)據(jù)了。
以上，就是Settings簡要分析，總結(jié)來說，就是對幾個(gè)特殊的將來可能用來保存共享數(shù)據(jù)的進(jìn)程進(jìn)行初始化工作，比如該進(jìn)程具有什么權(quán)限，支持什么功能等等。
3.2系統(tǒng)權(quán)限配置信息讀取和package.xml文件掃描解析
//......
// SystemConfig這個(gè)類掃描/etc/sysconfig和/etc/permissions/目錄，
//解析XML文件獲取到系統(tǒng)所有權(quán)限配置信息。
ArrayMap<String, SystemConfig.PermissionEntry> permConfig
= systemConfig.getPermissions();
//掃描解析/data/system/package.xml文件，這個(gè)文件保存的是安裝包對應(yīng)的相關(guān)信息：包名、權(quán)限、簽名等
//當(dāng)有程序安裝、卸載、更新等操作時(shí)，這個(gè)文件會發(fā)生變更
mRestoredSettings = mSettings.readLPw(this, sUserManager.getUsers(false),
mSdkVersion, mOnlyCore);
3.3 相關(guān)jar和apk dex優(yōu)化處理（/system/framework/目錄下相關(guān)的jar和apk）
// Set flag to monitor and not change apk file paths when
// scanning install directories.
final int scanFlags = SCAN_NO_PATHS | SCAN_DEFER_DEX | SCAN_BOOTING | SCAN_INITIAL;
final ArraySet<String> alreadyDexOpted = new ArraySet<String>();
/**
* Add everything in the in the boot class path to the
* list of process files because dexopt will have been run
* if necessary during zygote startup.
*/
final String bootClassPath = System.getenv("BOOTCLASSPATH");
final String systemServerClassPath = System.getenv("SYSTEMSERVERCLASSPATH");
if (bootClassPath != null) {
String[] bootClassPathElements = splitString(bootClassPath, ':');
for (String element : bootClassPathElements) {
alreadyDexOpted.add(element);
}
} else {
Slog.w(TAG, "No BOOTCLASSPATH found!");
}
if (systemServerClassPath != null) {
String[] systemServerClassPathElements = splitString(systemServerClassPath, ':');
for (String element : systemServerClassPathElements) {
alreadyDexOpted.add(element);
}
} else {
Slog.w(TAG, "No SYSTEMSERVERCLASSPATH found!");
}
final List<String> allInstructionSets = InstructionSets.getAllInstructionSets();
final String[] dexCodeInstructionSets =
getDexCodeInstructionSets(
allInstructionSets.toArray(new String[allInstructionSets.size()]));
/**
* Ensure all external libraries have had dexopt run on them.
* 確保所有的依賴庫都進(jìn)行dex優(yōu)化
*/
if (mSharedLibraries.size() > 0) {
// NOTE: For now, we're compiling these system "shared libraries"
// (and framework jars) into all available architectures. It's possible
// to compile them only when we come across an app that uses them (there's
// already logic for that in scanPackageLI) but that adds some complexity.
for (String dexCodeInstructionSet : dexCodeInstructionSets) {
for (SharedLibraryEntry libEntry : mSharedLibraries.values()) {
final String lib = libEntry.path;
if (lib == null) {
continue;
}
try {
int dexoptNeeded = DexFile.getDexOptNeeded(lib, dexCodeInstructionSet,
"speed", false);
if (dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {
alreadyDexOpted.add(lib);
mInstaller.dexopt(lib, Process.SYSTEM_UID, dexCodeInstructionSet,
dexoptNeeded, DEXOPT_PUBLIC /*dexFlags*/);
}
} catch (FileNotFoundException e) {
Slog.w(TAG, "Library not found: " + lib);
} catch (IOException e) {
Slog.w(TAG, "Cannot dexopt " + lib + "; is it an APK or JAR? "
+ e.getMessage());
}
}
}
}
// /system/framework/
File frameworkDir = new File(Environment.getRootDirectory(), "framework");
// Gross hack for now: we know this file doesn't contain any
// code, so don't dexopt it to avoid the resulting log spew.
// 該APK不含任何代碼，所以不需要進(jìn)行dex優(yōu)化，以減少啟動時(shí)間
alreadyDexOpted.add(frameworkDir.getPath() + "/framework-res.apk");
// Gross hack for now: we know this file is only part of
// the boot class path for art, so don't dexopt it to
// avoid the resulting log spew.
alreadyDexOpted.add(frameworkDir.getPath() + "/core-libart.jar");
/**
* There are a number of commands implemented in Java, which
* we currently need to do the dexopt on so that they can be
* run from a non-root shell.
*/
String[] frameworkFiles = frameworkDir.list();// 獲取/system/framework/所有子目錄
if (frameworkFiles != null) {
// TODO: We could compile these only for the most preferred ABI. We should
// first double check that the dex files for these commands are not referenced
// by other system apps.
for (String dexCodeInstructionSet : dexCodeInstructionSets) {
for (int i=0; i<frameworkFiles.length; i++) {
File libPath = new File(frameworkDir, frameworkFiles[i]);
String path = libPath.getPath();
// Skip the file if we already did it.
if (alreadyDexOpted.contains(path)) {
continue;
}
// Skip the file if it is not a type we want to dexopt.
// 只對APK文件和JAR文件進(jìn)行dex優(yōu)化處理
if (!path.endsWith(".apk") && !path.endsWith(".jar")) {
continue;
}
try {
int dexoptNeeded = DexFile.getDexOptNeeded(path, dexCodeInstructionSet,
"speed", false);
if (dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {
// 對相關(guān)jar和apk文件進(jìn)行dex優(yōu)化
mInstaller.dexopt(path, Process.SYSTEM_UID, dexCodeInstructionSet,
dexoptNeeded, DEXOPT_PUBLIC /*dexFlags*/);
}
} catch (FileNotFoundException e) {
Slog.w(TAG, "Jar not found: " + path);
} catch (IOException e) {
Slog.w(TAG, "Exception reading jar: " + path, e);
}
}
}
}
final VersionInfo ver = mSettings.getInternalVersion();
mIsUpgrade = !Build.FINGERPRINT.equals(ver.fingerprint);
// when upgrading from pre-M, promote system app permissions from install to runtime
// 當(dāng)版本升級到22的時(shí)候，權(quán)限從原來的安裝的時(shí)候就設(shè)置好變成在運(yùn)行給出提示讓用戶選擇是否允許相關(guān)操作
mPromoteSystemApps =
mIsUpgrade && ver.sdkVersion <= Build.VERSION_CODES.LOLLIPOP_MR1;
// 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);
}
}
}
3.4掃描指定目錄下的APK文件，然后解析APK文件
//......
// Find base frameworks (resource packages without code).
// /system/framework/
scanDirLI(frameworkDir, PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR
| PackageParser.PARSE_IS_PRIVILEGED,
scanFlags | SCAN_NO_DEX, 0);
// Collect ordinary system packages.
// /system/app/ 系統(tǒng)應(yīng)用APK放置路徑
final File systemAppDir = new File(Environment.getRootDirectory(), "app");
scanDirLI(systemAppDir, PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR, scanFlags, 0);
// 掃描解析/data/app/目錄下的APK，我們安裝的APK放在這個(gè)目錄下面
scanDirLI(mAppInstallDir, 0, scanFlags | SCAN_REQUIRE_KNOWN, 0);
//......
/**
*掃描指定目錄下面的文件，獲取APK文件或是子目錄，
*然后通過scanPackageLI對APK文件或是子目錄進(jìn)行處理
*/
private void scanDirLI(File dir, int parseFlags, int scanFlags, long currentTime) {
final File[] files = dir.listFiles();
if (ArrayUtils.isEmpty(files)) {
Log.d(TAG, "No files in app dir " + dir);
return;
}
if (DEBUG_PACKAGE_SCANNING) {
Log.d(TAG, "Scanning app dir " + dir + " scanFlags=" + scanFlags
+ " flags=0x" + Integer.toHexString(parseFlags));
}
for (File file : files) {
final boolean isPackage = (isApkFile(file) || file.isDirectory())
&& !PackageInstallerService.isStageName(file.getName());
if (!isPackage) {// APK文件或是目錄才會處理
// Ignore entries which are not packages
continue;
}
try {
scanPackageLI(file, parseFlags | PackageParser.PARSE_MUST_BE_APK,
scanFlags, currentTime, null);
} catch (PackageManagerException e) {
Slog.w(TAG, "Failed to parse " + file + ": " + e.getMessage());
// Delete invalid userdata apps
if ((parseFlags & PackageParser.PARSE_IS_SYSTEM) == 0 &&
e.error == PackageManager.INSTALL_FAILED_INVALID_APK) {
logCriticalInfo(Log.WARN, "Deleting invalid package at " + file);
if (file.isDirectory()) {
mInstaller.rmPackageDir(file.getAbsolutePath());
} else {
file.delete();
}
}
}
}
}
private PackageParser.Package scanPackageLI(File scanFile, int parseFlags, int scanFlags,
long currentTime, UserHandle user) throws PackageManagerException {
if (DEBUG_INSTALL) Slog.d(TAG, "Parsing: " + scanFile);
parseFlags |= mDefParseFlags;
PackageParser pp = new PackageParser();
pp.setSeparateProcesses(mSeparateProcesses);
pp.setOnlyCoreApps(mOnlyCore);
pp.setDisplayMetrics(mMetrics);
if ((scanFlags & SCAN_TRUSTED_OVERLAY) != 0) {
parseFlags |= PackageParser.PARSE_TRUSTED_OVERLAY;
}
final PackageParser.Package pkg;
try {
// 對文件進(jìn)行解析處理，APK數(shù)據(jù)保存在PackageParser.Package 對象中
pkg = pp.parsePackage(scanFile, parseFlags);
} catch (PackageParserException e) {
throw PackageManagerException.from(e);
}
//APK更新升級相關(guān)邏輯
//......
}
PackageParser.parsePackage()
public Package parsePackage(File packageFile, int flags) throws PackageParserException {
if (packageFile.isDirectory()) {// 包含APK的路徑 比如/data/app/xxxx
return parseClusterPackage(packageFile, flags);
} else {//直接解析一個(gè)APK文件，比如/system/framework/framework-res.apk
return parseMonolithicPackage(packageFile, flags);
}
}
先看直接解析APK的方法：parseMonolithicPackage()
public Package parseMonolithicPackage(File apkFile, int flags) throws PackageParserException {
if (mOnlyCoreApps) {
final PackageLite lite = parseMonolithicPackageLite(apkFile, flags);
if (!lite.coreApp) {
throw new PackageParserException(INSTALL_PARSE_FAILED_MANIFEST_MALFORMED,
"Not a coreApp: " + apkFile);
}
}
// AssetManager初始化
final AssetManager assets = new AssetManager();
try {
final Package pkg = parseBaseApk(apkFile, assets, flags);
pkg.codePath = apkFile.getAbsolutePath();
return pkg;
} finally {
IoUtils.closeQuietly(assets);
}
}
創(chuàng)建了一個(gè)AssetManager對象，然后通過parseBaseApk()來解析APK文件,parseBaseApk主要是對AndroidManifest.xml文件進(jìn)行解析，然后把解析后的數(shù)據(jù)保存到Package中，詳細(xì)的解析過程這里略過，相關(guān)的數(shù)據(jù)保存對象如下圖：
QQ截圖20160811114726.png
3.5 對解析APK獲取的PackageParser.Package配置進(jìn)程相關(guān)信息，填充3.1中的Settings信息，最后保存到ArrayMap<String, PackageParser.Package> mPackages這個(gè)Map中。
3.6 packagemanagerservice構(gòu)造函數(shù)主要的工作總結(jié)如下：
1)對特定的一些系統(tǒng)進(jìn)程信息進(jìn)行設(shè)置處理，保存到Settings中；
2)通過解析/etc/permissions下的相關(guān)xml文件取得系統(tǒng)相關(guān)權(quán)限、系統(tǒng)具備的相關(guān)功能等信息；
3)通過解析/data/system/package.xml文件獲取已安裝應(yīng)用相關(guān)信息；
4)對相關(guān)的apk和jar進(jìn)行dex優(yōu)化處理，主要是/system/framework/目錄下的相關(guān)jar和apk，framework-res.apk就放置在該目錄下面；
5)解析特定目錄下的APK文件（主要是解析AndroidManifest.xml），獲取APK相關(guān)信息，保存到PackageParser.Package這個(gè)對象中；
6)依據(jù)sharedUserId這個(gè)配置來確定APK運(yùn)行在哪個(gè)進(jìn)程，然后把運(yùn)行的相關(guān)進(jìn)程信息加入到Settings中，使得系統(tǒng)能夠知道每個(gè)APK運(yùn)行在哪個(gè)進(jìn)程里面。
