Android(安卓)应用安装过程分析
16lz
2021-01-24
在之前的文章中，我们对PakageManagerService启动流程分析 做了简单的介绍，并对PMS系统的启动流程做了详细的解析。上面只是说到了Android的PMS的运行流程，而对于Android apk的整个安装流程并没有过多的介绍。本篇将重点介绍下Android apk的运行启动流程。
总结一下，关于apk的安装流程主要分为以下步骤：
- 将apk文件复制到data/app目录
- 解析apk信息
- dexopt操作
- 更新权限信息
- 完成安装,发送Intent.ACTION_PACKAGE_ADDED广播
用一张图说明一下：
此图可见，从PakageManagerService的启动到apk的安装完成，中间还是经历了很多的流程。
1， 将apk文件copy至data/app目录
在之前的文章我们说过，安装应用 Intent 的是 PackageInstallerActivity，但这个类厂商可以随意修改，这个类也并没有在 android.jar 中。PackageInstallerActivity 在安装过程中，实际调用的是 ApplicationPackageManager 里面的代码。
private void installCommon(Uri packageURI, PackageInstallObserver observer, int flags, String installerPackageName, VerificationParams verificationParams, ContainerEncryptionParams encryptionParams) { if (!"file".equals(packageURI.getScheme())) { throw new UnsupportedOperationException("Only file:// URIs are supported"); } if (encryptionParams != null) { throw new UnsupportedOperationException("ContainerEncryptionParams not supported"); } final String originPath = packageURI.getPath(); try { mPM.installPackage(originPath, observer.getBinder(), flags, installerPackageName, verificationParams, null); } catch (RemoteException ignored) { }}在 ApplicationPackageManager 中是通过 Binder 机制调用了 PackageManagerService 中的 installPackage 方法，在这个方法中有个核心的方法installPackageAsUser，也就是我们前面流程图看到的。
@Overridepublic void installPackage(String originPath, IPackageInstallObserver2 observer, int installFlags, String installerPackageName, VerificationParams verificationParams, String packageAbiOverride) { installPackageAsUser(originPath, observer, installFlags, installerPackageName, verificationParams, packageAbiOverride, UserHandle.getCallingUserId());}installPackageAsUser
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INSTALL_PACKAGES, null); final int callingUid = Binder.getCallingUid(); ... ... if ((callingUid == Process.SHELL_UID) || (callingUid == Process.ROOT_UID)) { installFlags |= PackageManager.INSTALL_FROM_ADB; } else { // Caller holds INSTALL_PACKAGES permission, so we're less strict // about installerPackageName. installFlags &= ~PackageManager.INSTALL_FROM_ADB; installFlags &= ~PackageManager.INSTALL_ALL_USERS; } UserHandle user; if ((installFlags & PackageManager.INSTALL_ALL_USERS) != 0) { user = UserHandle.ALL; } else { user = new UserHandle(userId); } verificationParams.setInstallerUid(callingUid); final File originFile = new File(originPath); final OriginInfo origin = OriginInfo.fromUntrustedFile(originFile); final Message msg = mHandler.obtainMessage(INIT_COPY); msg.obj = new InstallParams(origin, observer, installFlags, installerPackageName, verificationParams, user, packageAbiOverride); mHandler.sendMessage(msg);这个方法主要是判断安装来源,包括adb,shell,all_user,然后像PMS的mHandler发送INIT_COPY的消息,这个mHandler运行在一个HandlerThread中。在接受到 INIT_COPY 消息后，将要安装的参数信息加入到 PendingInstalls 中去，如果是第一个安装，还需要发送 MCS_BOUND 消息，用于触发实际安装过程。
case INIT_COPY: { HandlerParams params = (HandlerParams) msg.obj; int idx = mPendingInstalls.size(); if (DEBUG_INSTALL) Slog.i(TAG, "init_copy idx=" + idx + ": " + params); // If a bind was already initiated we dont really // need to do anything. The pending install // will be processed later on. if (!mBound) { // If this is the only one pending we might // have to bind to the service again. if (!connectToService()) { Slog.e(TAG, "Failed to bind to media container service"); params.serviceError(); return; } else { // Once we bind to the service, the first // pending request will be processed. mPendingInstalls.add(idx, params); } } else { mPendingInstalls.add(idx, params); // Already bound to the service. Just make // sure we trigger off processing the first request. if (idx == 0) { mHandler.sendEmptyMessage(MCS_BOUND); } } break;}HandlerParams.startCopy
在 MCS_BOUND 消息中取出第一个安装请求，并调用 startCopy 方法。
HandlerParams params = mPendingInstalls.get(0);if (params != null) { if (params.startCopy()) { // ... } // ...}handleStartCopy()
在 startCopy 中调用 handleStartCopy 方法，由于这个类，需要与 MCS (MediaContainerService) 进行通信，有可能发生异常，因而这里设置了重试机制。
if (++mRetries > MAX_RETRIES) { Slog.w(TAG, "Failed to invoke remote methods on default container service. Giving up"); mHandler.sendEmptyMessage(MCS_GIVE_UP); handleServiceError(); return false;} else { handleStartCopy(); res = true;}handleReturnCode();handleStartCopy的核心就是copyApk,其他的都是些存储空间检查,权限检查等等安全校验。
2， 解析apk信息
完成apk copy到data/app目录的操作后,下一步就到了 handleReturnCode,这个方法又跳转到processPendingInstall()方法,下面先来看看processPendingInstall()方法。
private void processPendingInstall(final InstallArgs args, final int currentStatus) { // Queue up an async operation since the package installation may take a little while. mHandler.post(new Runnable() { public void run() { mHandler.removeCallbacks(this); // Result object to be returned PackageInstalledInfo res = new PackageInstalledInfo(); res.returnCode = currentStatus; res.uid = -1; res.pkg = null; res.removedInfo = new PackageRemovedInfo(); if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) { args.doPreInstall(res.returnCode); synchronized (mInstallLock) { installPackageLI(args, res); //1.安装 } args.doPostInstall(res.returnCode, res.uid); } // A restore should be performed at this point if (a) the install // succeeded, (b) the operation is not an update, and (c) the new // package has not opted out of backup participation. final boolean update = res.removedInfo.removedPackage != null; final int flags = (res.pkg == null) ? 0 : res.pkg.applicationInfo.flags; boolean doRestore = !update && ((flags & ApplicationInfo.FLAG_ALLOW_BACKUP) != 0); // Set up the post-install work request bookkeeping. This will be used // and cleaned up by the post-install event handling regardless of whether // there's a restore pass performed. Token values are >= 1. int token; if (mNextInstallToken < 0) mNextInstallToken = 1; token = mNextInstallToken++; PostInstallData data = new PostInstallData(args, res); mRunningInstalls.put(token, data); if (DEBUG_INSTALL) Log.v(TAG, "+ starting restore round-trip " + token); if (res.returnCode == PackageManager.INSTALL_SUCCEEDED && doRestore) { // Pass responsibility to the Backup Manager. It will perform a // restore if appropriate, then pass responsibility back to the // Package Manager to run the post-install observer callbacks // and broadcasts. IBackupManager bm = IBackupManager.Stub.asInterface( ServiceManager.getService(Context.BACKUP_SERVICE)); if (bm != null) { if (DEBUG_INSTALL) Log.v(TAG, "token " + token + " to BM for possible restore"); try { bm.restoreAtInstall(res.pkg.applicationInfo.packageName, token); //2.调用backup服务 } catch (RemoteException e) { // can't happen; the backup manager is local } catch (Exception e) { Slog.e(TAG, "Exception trying to enqueue restore", e); doRestore = false; } } else { Slog.e(TAG, "Backup Manager not found!"); doRestore = false; } } if (!doRestore) { // No restore possible, or the Backup Manager was mysteriously not // available -- just fire the post-install work request directly. if (DEBUG_INSTALL) Log.v(TAG, "No restore - queue post-install for " + token); Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0); mHandler.sendMessage(msg); } } }); }在这个方法有几个关键步骤：
一是installPackageLI(args, res);,这个方法具体执行了解析package和后续操作,
而再installPackageLI(args, res);执行完毕后会走到bm.restoreAtInstall(res.pkg.applicationInfo.packageName, token);,会调用backupservice的restoreAtInstall方法,而restoreAtInstall方法最终又会调用PMS的finishPackageInstall()方法,完成安装。
installPackageLI
private void installPackageLI(InstallArgs args, PackageInstalledInfo res) { final int installFlags = args.installFlags; String installerPackageName = args.installerPackageName; File tmpPackageFile = new File(args.getCodePath()); boolean forwardLocked = ((installFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0); boolean onSd = ((installFlags & PackageManager.INSTALL_EXTERNAL) != 0); boolean replace = false; final int scanFlags = SCAN_NEW_INSTALL | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE; // Result object to be returned res.returnCode = PackageManager.INSTALL_SUCCEEDED; if (DEBUG_INSTALL) Slog.d(TAG, "installPackageLI: path=" + tmpPackageFile); // Retrieve PackageSettings and parse package final int parseFlags = mDefParseFlags | PackageParser.PARSE_CHATTY | (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0) | (onSd ? PackageParser.PARSE_ON_SDCARD : 0); PackageParser pp = new PackageParser(); pp.setSeparateProcesses(mSeparateProcesses); pp.setDisplayMetrics(mMetrics); final PackageParser.Package pkg; try { pkg = pp.parsePackage(tmpPackageFile, parseFlags); } catch (PackageParserException e) { res.setError("Failed parse during installPackageLI", e); return; } // Mark that we have an install time CPU ABI override. pkg.cpuAbiOverride = args.abiOverride; String pkgName = res.name = pkg.packageName; if ((pkg.applicationInfo.flags&ApplicationInfo.FLAG_TEST_ONLY) != 0) { if ((installFlags & PackageManager.INSTALL_ALLOW_TEST) == 0) { res.setError(INSTALL_FAILED_TEST_ONLY, "installPackageLI"); return; } } try { pp.collectCertificates(pkg, parseFlags); pp.collectManifestDigest(pkg); } catch (PackageParserException e) { res.setError("Failed collect during installPackageLI", e); return; } /* If the installer passed in a manifest digest, compare it now. */ if (args.manifestDigest != null) { if (DEBUG_INSTALL) { final String parsedManifest = pkg.manifestDigest == null ? "null" : pkg.manifestDigest.toString(); Slog.d(TAG, "Comparing manifests: " + args.manifestDigest.toString() + " vs. " + parsedManifest); } if (!args.manifestDigest.equals(pkg.manifestDigest)) { res.setError(INSTALL_FAILED_PACKAGE_CHANGED, "Manifest digest changed"); return; } } else if (DEBUG_INSTALL) { final String parsedManifest = pkg.manifestDigest == null ? "null" : pkg.manifestDigest.toString(); Slog.d(TAG, "manifestDigest was not present, but parser got: " + parsedManifest); } // Get rid of all references to package scan path via parser. pp = null; String oldCodePath = null; boolean systemApp = false; synchronized (mPackages) { // Check whether the newly-scanned package wants to define an already-defined perm int N = pkg.permissions.size(); for (int i = N-1; i >= 0; i--) { PackageParser.Permission perm = pkg.permissions.get(i); BasePermission bp = mSettings.mPermissions.get(perm.info.name); if (bp != null) { // If the defining package is signed with our cert, it's okay. This // also includes the "updating the same package" case, of course. // "updating same package" could also involve key-rotation. final boolean sigsOk; if (!bp.sourcePackage.equals(pkg.packageName) || !(bp.packageSetting instanceof PackageSetting) || !bp.packageSetting.keySetData.isUsingUpgradeKeySets() || ((PackageSetting) bp.packageSetting).sharedUser != null) { sigsOk = compareSignatures(bp.packageSetting.signatures.mSignatures, pkg.mSignatures) == PackageManager.SIGNATURE_MATCH; } else { sigsOk = checkUpgradeKeySetLP((PackageSetting) bp.packageSetting, pkg); } if (!sigsOk) { // If the owning package is the system itself, we log but allow // install to proceed; we fail the install on all other permission // redefinitions. if (!bp.sourcePackage.equals("android")) { res.setError(INSTALL_FAILED_DUPLICATE_PERMISSION, "Package " + pkg.packageName + " attempting to redeclare permission " + perm.info.name + " already owned by " + bp.sourcePackage); res.origPermission = perm.info.name; res.origPackage = bp.sourcePackage; return; } else { Slog.w(TAG, "Package " + pkg.packageName + " attempting to redeclare system permission " + perm.info.name + "; ignoring new declaration"); pkg.permissions.remove(i); } } } } // Check if installing already existing package if ((installFlags & PackageManager.INSTALL_REPLACE_EXISTING) != 0) { String oldName = mSettings.mRenamedPackages.get(pkgName); if (pkg.mOriginalPackages != null && pkg.mOriginalPackages.contains(oldName) && mPackages.containsKey(oldName)) { // This package is derived from an original package, // and this device has been updating from that original // name. We must continue using the original name, so // rename the new package here. pkg.setPackageName(oldName); pkgName = pkg.packageName; replace = true; if (DEBUG_INSTALL) Slog.d(TAG, "Replacing existing renamed package: oldName=" + oldName + " pkgName=" + pkgName); } else if (mPackages.containsKey(pkgName)) { // This package, under its official name, already exists // on the device; we should replace it. replace = true; if (DEBUG_INSTALL) Slog.d(TAG, "Replace existing pacakge: " + pkgName); } } PackageSetting ps = mSettings.mPackages.get(pkgName); if (ps != null) { if (DEBUG_INSTALL) Slog.d(TAG, "Existing package: " + ps); oldCodePath = mSettings.mPackages.get(pkgName).codePathString; if (ps.pkg != null && ps.pkg.applicationInfo != null) { systemApp = (ps.pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0; } res.origUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true); } } if (systemApp && onSd) { // Disable updates to system apps on sdcard res.setError(INSTALL_FAILED_INVALID_INSTALL_LOCATION, "Cannot install updates to system apps on sdcard"); return; } if (!args.doRename(res.returnCode, pkg, oldCodePath)) { res.setError(INSTALL_FAILED_INSUFFICIENT_STORAGE, "Failed rename"); return; } if (replace) { replacePackageLI(pkg, parseFlags, scanFlags | SCAN_REPLACING, args.user, installerPackageName, res); } else { installNewPackageLI(pkg, parseFlags, scanFlags | SCAN_DELETE_DATA_ON_FAILURES, args.user, installerPackageName, res); } synchronized (mPackages) { final PackageSetting ps = mSettings.mPackages.get(pkgName); if (ps != null) { res.newUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true); } } }这个方法先是解析了package包,然后做了大量签名和权限校验的工作，最终走到判断是安装新的apk还是覆盖安装的判断语句上。
if (replace) { replacePackageLI(pkg, parseFlags, scanFlags | SCAN_REPLACING, args.user, installerPackageName, res); } else { installNewPackageLI(pkg, parseFlags, scanFlags | SCAN_DELETE_DATA_ON_FAILURES, args.user, installerPackageName, res); }installNewPackageLI()
private void installNewPackageLI(PackageParser.Package pkg, int parseFlags, int scanFlags, UserHandle user, String installerPackageName, PackageInstalledInfo res) { // Remember this for later, in case we need to rollback this install String pkgName = pkg.packageName; if (DEBUG_INSTALL) Slog.d(TAG, "installNewPackageLI: " + pkg); boolean dataDirExists = getDataPathForPackage(pkg.packageName, 0).exists(); synchronized(mPackages) { if (mSettings.mRenamedPackages.containsKey(pkgName)) { // A package with the same name is already installed, though // it has been renamed to an older name. The package we // are trying to install should be installed as an update to // the existing one, but that has not been requested, so bail. res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName + " without first uninstalling package running as " + mSettings.mRenamedPackages.get(pkgName)); return; } if (mPackages.containsKey(pkgName)) { // Don't allow installation over an existing package with the same name. res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName + " without first uninstalling."); return; } } try { PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags, scanFlags, System.currentTimeMillis(), user); updateSettingsLI(newPackage, installerPackageName, null, null, res); // delete the partially installed application. the data directory will have to be // restored if it was already existing if (res.returnCode != PackageManager.INSTALL_SUCCEEDED) { // remove package from internal structures. Note that we want deletePackageX to // delete the package data and cache directories that it created in // scanPackageLocked, unless those directories existed before we even tried to // install. deletePackageLI(pkgName, UserHandle.ALL, false, null, null, dataDirExists ? PackageManager.DELETE_KEEP_DATA : 0, res.removedInfo, true); } } catch (PackageManagerException e) { res.setError("Package couldn't be installed in " + pkg.codePath, e); } }这个方法核心的步骤有两个:
- PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags,
scanFlags,System.currentTimeMillis(), user); - updateSettingsLI(newPackage, installerPackageName, null, null, res);
scanPackageLI负责安装,而updateSettingLI则是完成安装后的设置信息更新。
scanPackageLI()
scanPackageLI()方法主要逻辑是由scanPackageDirtyLI()实现的，在这个方法中主要做了如下的操作：
- 设置系统App的一些参数
- 校验签名
- 解析app的provider,校验是否与已有的provider冲突
- 32/64位abi的一些设置
- 四大组件的解析，注册
3，dexopt操作
Apk文件其实就是一个归档zip压缩包,而我们编写的代码最终都编译成了.dex文件,但为了提高运行性能,android系统并不会直接执行.dex,而是会在安装过程中执行dexopt操作来优化.dex文件,最终android系统执行的时优化后的’odex’文件(注意:这个odex文件的后缀也是.dex,其路径在data/dalvik-cache)。对于dalvik虚拟机,dexopt就是优化操作,而对于art虚拟机,dexopt执行的则是dex2oat操作,既将.dex文件翻译成oat文件。关于art和dex2oat的更多信息请自行搜索相关资料。
performDexOptLI()
performDexOptLI的一个核心方法：
final int ret = mInstaller.dexopt(path, sharedGid, !isForwardLocked(pkg), pkg.packageName, dexCodeInstructionSet, vmSafeMode);本方法的核心就是调用PMS的mInstaller成员变量的dexopt操作。
Installer.dexopt
Installer类的dexopt方法又调用InstallerConnection类的dexopt方法。
public int dexopt(String apkPath, int uid, boolean isPublic, String pkgName, String instructionSet, boolean vmSafeMode) { StringBuilder builder = new StringBuilder("dexopt"); builder.append(' '); builder.append(apkPath); builder.append(' '); builder.append(uid); builder.append(isPublic ? " 1" : " 0"); builder.append(' '); builder.append(pkgName); builder.append(' '); builder.append(instructionSet); builder.append(' '); builder.append(vmSafeMode ? " 1" : " 0"); return execute(builder.toString()); } public synchronized String transact(String cmd) { if (!connect()) { Slog.e(TAG, "connection failed"); return "-1"; } if (!writeCommand(cmd)) { /* * If installd died and restarted in the background (unlikely but * possible) we'll fail on the next write (this one). Try to * reconnect and write the command one more time before giving up. */ Slog.e(TAG, "write command failed? reconnect!"); if (!connect() || !writeCommand(cmd)) { return "-1"; } } if (LOCAL_DEBUG) { Slog.i(TAG, "send: '" + cmd + "'"); } final int replyLength = readReply(); if (replyLength > 0) { String s = new String(buf, 0, replyLength); if (LOCAL_DEBUG) { Slog.i(TAG, "recv: '" + s + "'"); } return s; } else { if (LOCAL_DEBUG) { Slog.i(TAG, "fail"); } return "-1"; } } public int execute(String cmd) { String res = transact(cmd); try { return Integer.parseInt(res); } catch (NumberFormatException ex) { return -1; } } private boolean connect() { if (mSocket != null) { return true; } Slog.i(TAG, "connecting..."); try { mSocket = new LocalSocket(); LocalSocketAddress address = new LocalSocketAddress("installd", LocalSocketAddress.Namespace.RESERVED); mSocket.connect(address); mIn = mSocket.getInputStream(); mOut = mSocket.getOutputStream(); } catch (IOException ex) { disconnect(); return false; } return true; }由上面的几个方法可以知道,最终dexopt操作是通过socket的方式来跨进程通知守护进程installd,由其去执行dexopt操作。
dexopt()
最终守护进程installd会调用Commands.c文件(位于/source/framework/native/cmds/installd)的dexopt方法。
int dexopt(const char *apk_path, uid_t uid, bool is_public, const char *pkgname, const char *instruction_set, bool vm_safe_mode, bool is_patchoat){ struct utimbuf ut; struct stat input_stat, dex_stat; char out_path[PKG_PATH_MAX]; char persist_sys_dalvik_vm_lib[PROPERTY_VALUE_MAX]; char *end; const char *input_file; char in_odex_path[PKG_PATH_MAX]; int res, input_fd=-1, out_fd=-1; ... ... pid_t pid; pid = fork(); if (pid == 0) { /* child -- drop privileges before continuing */ if (setgid(uid) != 0) { ALOGE("setgid(%d) failed in installd during dexopt\n", uid); exit(64); } if (setuid(uid) != 0) { ALOGE("setuid(%d) failed in installd during dexopt\n", uid); exit(65); } // drop capabilities struct __user_cap_header_struct capheader; struct __user_cap_data_struct capdata[2]; memset(&capheader, 0, sizeof(capheader)); memset(&capdata, 0, sizeof(capdata)); capheader.version = _LINUX_CAPABILITY_VERSION_3; if (capset(&capheader, &capdata[0]) < 0) { ALOGE("capset failed: %s\n", strerror(errno)); exit(66); } if (set_sched_policy(0, SP_BACKGROUND) < 0) { ALOGE("set_sched_policy failed: %s\n", strerror(errno)); exit(70); } if (flock(out_fd, LOCK_EX | LOCK_NB) != 0) { ALOGE("flock(%s) failed: %s\n", out_path, strerror(errno)); exit(67); } if (strncmp(persist_sys_dalvik_vm_lib, "libdvm", 6) == 0) { run_dexopt(input_fd, out_fd, input_file, out_path); } else if (strncmp(persist_sys_dalvik_vm_lib, "libart", 6) == 0) { if (is_patchoat) { run_patchoat(input_fd, out_fd, input_file, out_path, pkgname, instruction_set); } else { run_dex2oat(input_fd, out_fd, input_file, out_path, pkgname, instruction_set, vm_safe_mode); } } else { exit(69); /* Unexpected persist.sys.dalvik.vm.lib value */ } exit(68); /* only get here on exec failure */ } else { res = wait_child(pid); if (res == 0) { ALOGV("DexInv: --- END '%s' (success) ---\n", input_file); } else { ALOGE("DexInv: --- END '%s' --- status=0x%04x, process failed\n", input_file, res); goto fail; } } ut.actime = input_stat.st_atime; ut.modtime = input_stat.st_mtime; utime(out_path, &ut); close(out_fd); close(input_fd); return 0;fail: if (out_fd >= 0) { close(out_fd); unlink(out_path); } if (input_fd >= 0) { close(input_fd); } return -1;}4，更新权限信息
dexopt操作执行完后,installNewPackageLI()方法就会走到updateSettingsLI()来更新设置信息,而更新设置信息主要是权限信息。更新权限信息最核心的方法是：updatePermissionsLPw()。
updatePermissionsLPw
private void updatePermissionsLPw(String changingPkg, PackageParser.Package pkgInfo, int flags) { // Make sure there are no dangling permission trees. Iterator<BasePermission> it = mSettings.mPermissionTrees.values().iterator(); while (it.hasNext()) { final BasePermission bp = it.next(); if (bp.packageSetting == null) { // We may not yet have parsed the package, so just see if // we still know about its settings. bp.packageSetting = mSettings.mPackages.get(bp.sourcePackage); } if (bp.packageSetting == null) { Slog.w(TAG, "Removing dangling permission tree: " + bp.name + " from package " + bp.sourcePackage); it.remove(); } else if (changingPkg != null && changingPkg.equals(bp.sourcePackage)) { if (pkgInfo == null || !hasPermission(pkgInfo, bp.name)) { Slog.i(TAG, "Removing old permission tree: " + bp.name + " from package " + bp.sourcePackage); flags |= UPDATE_PERMISSIONS_ALL; it.remove(); } } } // Make sure all dynamic permissions have been assigned to a package, // and make sure there are no dangling permissions. it = mSettings.mPermissions.values().iterator(); while (it.hasNext()) { final BasePermission bp = it.next(); if (bp.type == BasePermission.TYPE_DYNAMIC) { if (DEBUG_SETTINGS) Log.v(TAG, "Dynamic permission: name=" + bp.name + " pkg=" + bp.sourcePackage + " info=" + bp.pendingInfo); if (bp.packageSetting == null && bp.pendingInfo != null) { final BasePermission tree = findPermissionTreeLP(bp.name); if (tree != null && tree.perm != null) { bp.packageSetting = tree.packageSetting; bp.perm = new PackageParser.Permission(tree.perm.owner, new PermissionInfo(bp.pendingInfo)); bp.perm.info.packageName = tree.perm.info.packageName; bp.perm.info.name = bp.name; bp.uid = tree.uid; } } } if (bp.packageSetting == null) { // We may not yet have parsed the package, so just see if // we still know about its settings. bp.packageSetting = mSettings.mPackages.get(bp.sourcePackage); } if (bp.packageSetting == null) { Slog.w(TAG, "Removing dangling permission: " + bp.name + " from package " + bp.sourcePackage); it.remove(); } else if (changingPkg != null && changingPkg.equals(bp.sourcePackage)) { if (pkgInfo == null || !hasPermission(pkgInfo, bp.name)) { Slog.i(TAG, "Removing old permission: " + bp.name + " from package " + bp.sourcePackage); flags |= UPDATE_PERMISSIONS_ALL; it.remove(); } } } // Now update the permissions for all packages, in particular // replace the granted permissions of the system packages. if ((flags&UPDATE_PERMISSIONS_ALL) != 0) { for (PackageParser.Package pkg : mPackages.values()) { if (pkg != pkgInfo) { grantPermissionsLPw(pkg, (flags&UPDATE_PERMISSIONS_REPLACE_ALL) != 0, changingPkg); } } } if (pkgInfo != null) { grantPermissionsLPw(pkgInfo, (flags&UPDATE_PERMISSIONS_REPLACE_PKG) != 0, changingPkg); } } private void grantPermissionsLPw(PackageParser.Package pkg, boolean replace, String packageOfInterest) { final PackageSetting ps = (PackageSetting) pkg.mExtras; if (ps == null) { return; } final GrantedPermissions gp = ps.sharedUser != null ? ps.sharedUser : ps; HashSet<String> origPermissions = gp.grantedPermissions; boolean changedPermission = false; if (replace) { ps.permissionsFixed = false; if (gp == ps) { origPermissions = new HashSet<String>(gp.grantedPermissions); gp.grantedPermissions.clear(); gp.gids = mGlobalGids; } } if (gp.gids == null) { gp.gids = mGlobalGids; } final int N = pkg.requestedPermissions.size(); for (int i=0; i<N; i++) { final String name = pkg.requestedPermissions.get(i); final boolean required = pkg.requestedPermissionsRequired.get(i); final BasePermission bp = mSettings.mPermissions.get(name); if (DEBUG_INSTALL) { if (gp != ps) { Log.i(TAG, "Package " + pkg.packageName + " checking " + name + ": " + bp); } } if (bp == null || bp.packageSetting == null) { if (packageOfInterest == null || packageOfInterest.equals(pkg.packageName)) { Slog.w(TAG, "Unknown permission " + name + " in package " + pkg.packageName); } continue; } final String perm = bp.name; boolean allowed; boolean allowedSig = false; if ((bp.protectionLevel&PermissionInfo.PROTECTION_FLAG_APPOP) != 0) { // Keep track of app op permissions. ArraySet<String> pkgs = mAppOpPermissionPackages.get(bp.name); if (pkgs == null) { pkgs = new ArraySet<>(); mAppOpPermissionPackages.put(bp.name, pkgs); } pkgs.add(pkg.packageName); } final int level = bp.protectionLevel & PermissionInfo.PROTECTION_MASK_BASE; if (level == PermissionInfo.PROTECTION_NORMAL || level == PermissionInfo.PROTECTION_DANGEROUS) { // We grant a normal or dangerous permission if any of the following // are true: // 1) The permission is required // 2) The permission is optional, but was granted in the past // 3) The permission is optional, but was requested by an // app in /system (not /data) // // Otherwise, reject the permission. allowed = (required || origPermissions.contains(perm) || (isSystemApp(ps) && !isUpdatedSystemApp(ps))); } else if (bp.packageSetting == null) { // This permission is invalid; skip it. allowed = false; } else if (level == PermissionInfo.PROTECTION_SIGNATURE) { allowed = grantSignaturePermission(perm, pkg, bp, origPermissions); if (allowed) { allowedSig = true; } } else { allowed = false; } if (DEBUG_INSTALL) { if (gp != ps) { Log.i(TAG, "Package " + pkg.packageName + " granting " + perm); } } if (allowed) { if (!isSystemApp(ps) && ps.permissionsFixed) { // If this is an existing, non-system package, then // we can't add any new permissions to it. if (!allowedSig && !gp.grantedPermissions.contains(perm)) { // Except... if this is a permission that was added // to the platform (note: need to only do this when // updating the platform). allowed = isNewPlatformPermissionForPackage(perm, pkg); } } if (allowed) { if (!gp.grantedPermissions.contains(perm)) { changedPermission = true; gp.grantedPermissions.add(perm); gp.gids = appendInts(gp.gids, bp.gids); } else if (!ps.haveGids) { gp.gids = appendInts(gp.gids, bp.gids); } } else { if (packageOfInterest == null || packageOfInterest.equals(pkg.packageName)) { Slog.w(TAG, "Not granting permission " + perm + " to package " + pkg.packageName + " because it was previously installed without"); } } } else { if (gp.grantedPermissions.remove(perm)) { changedPermission = true; gp.gids = removeInts(gp.gids, bp.gids); Slog.i(TAG, "Un-granting permission " + perm + " from package " + pkg.packageName + " (protectionLevel=" + bp.protectionLevel + " flags=0x" + Integer.toHexString(pkg.applicationInfo.flags) + ")"); } else if ((bp.protectionLevel&PermissionInfo.PROTECTION_FLAG_APPOP) == 0) { // Don't print warning for app op permissions, since it is fine for them // not to be granted, there is a UI for the user to decide. if (packageOfInterest == null || packageOfInterest.equals(pkg.packageName)) { Slog.w(TAG, "Not granting permission " + perm + " to package " + pkg.packageName + " (protectionLevel=" + bp.protectionLevel + " flags=0x" + Integer.toHexString(pkg.applicationInfo.flags) + ")"); } } } } if ((changedPermission || replace) && !ps.permissionsFixed && !isSystemApp(ps) || isUpdatedSystemApp(ps)){ // This is the first that we have heard about this package, so the // permissions we have now selected are fixed until explicitly // changed. ps.permissionsFixed = true; } ps.haveGids = true; }在apk的安装时PMS会将该app的所有权限都记录下来并更新到PMS的mAppOpPermissionPackages成员变量里面,并判定是否授予该app请求的权限。
5，完成安装，发广播
processPendingInstall方法在执行installPackageLi后会执行以下语句。
if (res.returnCode == PackageManager.INSTALL_SUCCEEDED && doRestore) { // Pass responsibility to the Backup Manager. It will perform a // restore if appropriate, then pass responsibility back to the // Package Manager to run the post-install observer callbacks // and broadcasts. IBackupManager bm = IBackupManager.Stub.asInterface( ServiceManager.getService(Context.BACKUP_SERVICE)); if (bm != null) { if (DEBUG_INSTALL) Log.v(TAG, "token " + token + " to BM for possible restore"); try { bm.restoreAtInstall(res.pkg.applicationInfo.packageName, token); } catch (RemoteException e) { // can't happen; the backup manager is local } catch (Exception e) { Slog.e(TAG, "Exception trying to enqueue restore", e); doRestore = false; } } else { Slog.e(TAG, "Backup Manager not found!"); doRestore = false; } }在BackupManagerService的restoreAtInstall方法中会有以下代码：
... if (skip) { // Auto-restore disabled or no way to attempt a restore; just tell the Package // Manager to proceed with the post-install handling for this package. if (DEBUG) Slog.v(TAG, "Finishing install immediately"); try { mPackageManagerBinder.finishPackageInstall(token); } catch (RemoteException e) { /* can't happen */ } }...restoreAtInstall方法最终会调用PMS的finishPackageInstall方法,而此方法最终会发送Intent.ACTION_PACKAGE_ADDED广播，apk的安装就到到此结束。
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