image
接着上一篇文章的代码逻辑来查看PMS的installStage方法。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
void installStage(String packageName, File stagedDir, String stagedCid, IPackageInstallObserver2 observer, PackageInstaller.SessionParams sessionParams, String installerPackageName, int installerUid, UserHandle user, Certificate[][] certificates) { ... final Message msg = mHandler.obtainMessage(INIT_COPY);//1 final int installReason = fixUpInstallReason(installerPackageName, installerUid, sessionParams.installReason); final InstallParams params = new InstallParams(origin, null, observer, sessionParams.installFlags, installerPackageName, sessionParams.volumeUuid, verificationInfo, user, sessionParams.abiOverride, sessionParams.grantedRuntimePermissions, certificates, installReason);//2 params.setTraceMethod("installStage").setTraceCookie(System.identityHashCode(params)); msg.obj = params; ... mHandler.sendMessage(msg);//3 }
注释2处创建InstallParams,它对应于包的安装数据。注释1处创建了类型为INIT_COPY的消息,在注释3处将InstallParams通过消息发送出去。
处理INIT_COPY类型的消息的代码如下所示。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#PackageHandler
void doHandleMessage(Message msg) { switch (msg.what) { case INIT_COPY: { HandlerParams params = (HandlerParams) msg.obj; int idx = mPendingInstalls.size(); if (DEBUG_INSTALL) Slog.i(TAG, "init_copy idx=" + idx + ": " + params); //mBound用于标识是否绑定了服务,默认值为false if (!mBound) {//1 Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "bindingMCS", System.identityHashCode(mHandler)); //如果没有绑定服务,重新绑定,connectToService方法内部如果绑定成功会将mBound置为true if (!connectToService()) {//2 Slog.e(TAG, "Failed to bind to media container service"); params.serviceError(); Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, "bindingMCS", System.identityHashCode(mHandler)); if (params.traceMethod != null) { Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, params.traceMethod, params.traceCookie); } //绑定服务失败则return return; } else { //绑定服务成功,将请求添加到ArrayList类型的mPendingInstalls中,等待处理 mPendingInstalls.add(idx, params); } } else { //已经绑定服务 mPendingInstalls.add(idx, params); if (idx == 0) { mHandler.sendEmptyMessage(MCS_BOUND);//3 } } break; } .... } } }
PackageHandler继承自Handler,它被定义在PMS中,doHandleMessage方法用于处理各个类型的消息,来查看对INIT_COPY类型消息的处理。注释1处的mBound用于标识是否绑定了DefaultContainerService,默认值为false。DefaultContainerService是用于检查和复制可移动文件的服务,这是一个比较耗时的操作,因此DefaultContainerService没有和PMS运行在同一进程中,它运行在com.android.defcontainer进程,通过IMediaContainerService和PMS进行IPC通信,如下图所示。
image
注释2处的connectToService方法用来绑定DefaultContainerService,注释3处发送MCS_BOUND类型的消息,触发处理第一个安装请求。
查看注释2处的connectToService方法:
**frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#PackageHandler **
private boolean connectToService() { if (DEBUG_SD_INSTALL) Log.i(TAG, "Trying to bind to" + " DefaultContainerService"); Intent service = new Intent().setComponent(DEFAULT_CONTAINER_COMPONENT); Process.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT); if (mContext.bindServiceAsUser(service, mDefContainerConn, Context.BIND_AUTO_CREATE, UserHandle.SYSTEM)) {//1 Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); mBound = true;//2 return true; } Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); return false; }
注释2处如果绑定DefaultContainerService成功,mBound会置为ture 。注释1处的bindServiceAsUser方法会传入mDefContainerConn,bindServiceAsUser方法的处理逻辑和我们调用bindService是类似的,服务建立连接后,会调用onServiceConnected方法:
**frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java **
class DefaultContainerConnection implements ServiceConnection { public void onServiceConnected(ComponentName name, IBinder service) { if (DEBUG_SD_INSTALL) Log.i(TAG, "onServiceConnected"); final IMediaContainerService imcs = IMediaContainerService.Stub .asInterface(Binder.allowBlocking(service)); mHandler.sendMessage(mHandler.obtainMessage(MCS_BOUND, Object));//1 } public void onServiceDisconnected(ComponentName name) { if (DEBUG_SD_INSTALL) Log.i(TAG, "onServiceDisconnected"); } }
注释1处发送了MCS_BOUND类型的消息,与PackageHandler.doHandleMessage
方法的注释3处不同的是,这里发送消息带了Object类型的参数,这里会对这两种情况来进行讲解,一种是消息不带Object类型的参数,一种是消息带Object类型的参数。
消息不带Object类型的参数
查看对MCS_BOUND类型消息的处理:
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
case MCS_BOUND: { if (DEBUG_INSTALL) Slog.i(TAG, "mcs_bound"); if (msg.obj != null) {//1 mContainerService = (IMediaContainerService) msg.obj;//2 Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, "bindingMCS", System.identityHashCode(mHandler)); } if (mContainerService == null) {//3 if (!mBound) {//4 Slog.e(TAG, "Cannot bind to media container service"); for (HandlerParams params : mPendingInstalls) { params.serviceError();//5 Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, "queueInstall", System.identityHashCode(params)); if (params.traceMethod != null) { Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, params.traceMethod, params.traceCookie); } return; } //绑定失败,清空安装请求队列 mPendingInstalls.clear(); } else { //继续等待绑定服务 Slog.w(TAG, "Waiting to connect to media container service"); } } else if (mPendingInstalls.size() > 0) { ... else { Slog.w(TAG, "Empty queue"); } break; }
如果消息不带Object类型的参数,就无法满足注释1处的条件,注释2处的IMediaContainerService类型的mContainerService也无法被赋值,这样就满足了注释3处的条件。
如果满足注释4处的条件,说明还没有绑定服务,而此前已经在PackageHandler.doHandleMessage
方法的注释2处调用绑定服务的方法了,这显然是不正常的,因此在注释5处负责处理服务发生错误的情况。如果不满足注释4处的条件,说明已经绑定服务了,就会打印出系统log,告知用户等待系统绑定服务。
消息带Object类型的参数
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
case MCS_BOUND: { if (DEBUG_INSTALL) Slog.i(TAG, "mcs_bound"); if (msg.obj != null) { ... } if (mContainerService == null) {//1 ... } else if (mPendingInstalls.size() > 0) {//2 HandlerParams params = mPendingInstalls.get(0);//3 if (params != null) { Trace.asyncTraceEnd(TRACE_TAG_PACKAGE_MANAGER, "queueInstall", System.identityHashCode(params)); Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "startCopy"); if (params.startCopy()) {//4 if (DEBUG_SD_INSTALL) Log.i(TAG, "Checking for more work or unbind..."); //如果APK安装成功,删除本次安装请求 if (mPendingInstalls.size() > 0) { mPendingInstalls.remove(0); } if (mPendingInstalls.size() == 0) { if (mBound) { //如果没有安装请求了,发送解绑服务的请求 if (DEBUG_SD_INSTALL) Log.i(TAG, "Posting delayed MCS_UNBIND"); removeMessages(MCS_UNBIND); Message ubmsg = obtainMessage(MCS_UNBIND); sendMessageDelayed(ubmsg, 10000); } } else { if (DEBUG_SD_INSTALL) Log.i(TAG, "Posting MCS_BOUND for next work"); //如果还有其他的安装请求,接着发送MCS_BOUND消息继续处理剩余的安装请求 mHandler.sendEmptyMessage(MCS_BOUND);//5 } } Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER); }else { Slog.w(TAG, "Empty queue");//6 } break; }
如果MCS_BOUND类型消息带Object类型的参数就不会满足注释1处的条件,就会调用注释2处的判断,如果安装请求数不大于0就会打印出注释6处的log,说明安装请求队列是空的。安装完一个APK后,就会在注释5处发出MSC_BOUND消息,继续处理剩下的安装请求直到安装请求队列为空。
注释3处得到安装请求队列第一个请求HandlerParams ,如果HandlerParams 不为null就会调用注释4处的HandlerParams的startCopy方法,用于开始复制APK的流程。
先来查看复制APK的时序图。
image
HandlerParams是PMS中的抽象类,它的实现类为PMS的内部类InstallParams。HandlerParams的startCopy方法如下所示。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#HandlerParams
final boolean startCopy() { boolean res; try { if (DEBUG_INSTALL) Slog.i(TAG, "startCopy " + mUser + ": " + this); //startCopy方法尝试的次数,超过了4次,就放弃这个安装请求 if (++mRetries > MAX_RETRIES) {//1 Slog.w(TAG, "Failed to invoke remote methods on default container service. Giving up"); mHandler.sendEmptyMessage(MCS_GIVE_UP);//2 handleServiceError(); return false; } else { handleStartCopy();//3 res = true; } } catch (RemoteException e) { if (DEBUG_INSTALL) Slog.i(TAG, "Posting install MCS_RECONNECT"); mHandler.sendEmptyMessage(MCS_RECONNECT); res = false; } handleReturnCode();//4 return res; }
注释1处的mRetries用于记录startCopy方法调用的次数,调用startCopy方法时会先自动加1,如果次数大于4次就放弃这个安装请求:在注释2处发送MCS_GIVE_UP类型消息,将第一个安装请求(本次安装请求)从安装请求队列mPendingInstalls中移除掉。注释4处用于处理复制APK后的安装APK逻辑,第3小节中会再次提到它。注释3处调用了抽象方法handleStartCopy,它的实现在InstallParams中,如下所示。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#InstallParams
public void handleStartCopy() throws RemoteException { ... //确定APK的安装位置。onSd:安装到SD卡, onInt:内部存储即Data分区,ephemeral:安装到临时存储(Instant Apps安装) final boolean onSd = (installFlags & PackageManager.INSTALL_EXTERNAL) != 0; final boolean onInt = (installFlags & PackageManager.INSTALL_INTERNAL) != 0; final boolean ephemeral = (installFlags & PackageManager.INSTALL_INSTANT_APP) != 0; PackageInfoLite pkgLite = null; if (onInt && onSd) { // APK不能同时安装在SD卡和Data分区 Slog.w(TAG, "Conflicting flags specified for installing on both internal and external"); ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION; //安装标志冲突,Instant Apps不能安装到SD卡中 } else if (onSd && ephemeral) { Slog.w(TAG, "Conflicting flags specified for installing ephemeral on external"); ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION; } else { //获取APK的少量的信息 pkgLite = mContainerService.getMinimalPackageInfo(origin.resolvedPath, installFlags, packageAbiOverride);//1 if (DEBUG_EPHEMERAL && ephemeral) { Slog.v(TAG, "pkgLite for install: " + pkgLite); } ... if (ret == PackageManager.INSTALL_SUCCEEDED) { //判断安装的位置 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{ loc = installLocationPolicy(pkgLite);//2 ... } } //根据InstallParams创建InstallArgs对象 final InstallArgs args = createInstallArgs(this);//3 mArgs = args; if (ret == PackageManager.INSTALL_SUCCEEDED) { ... if (!origin.existing && requiredUid != -1 && isVerificationEnabled( verifierUser.getIdentifier(), installFlags, installerUid)) { ... } else{ ret = args.copyApk(mContainerService, true);//4 } } mRet = ret; }
handleStartCopy方法的代码很多,这里截取关键的部分。
注释1处通过IMediaContainerService跨进程调用DefaultContainerService的getMinimalPackageInfo方法,该方法轻量解析APK并得到APK的少量信息,轻量解析的原因是这里不需要得到APK的全部信息,APK的少量信息会封装到PackageInfoLite中。接着在注释2处确定APK的安装位置。注释3处创建了InstallArgs,InstallArgs 是一个抽象类,定义了APK的安装逻辑,比如复制和重命名APK等,它有3个子类,都被定义在PMS中,如下图所示。
image
其中FileInstallArgs用于处理安装到非ASEC的存储空间的APK,也就是内部存储空间(Data分区),AsecInstallArgs用于处理安装到ASEC中(mnt/asec)即SD卡中的APK。MoveInstallArgs用于处理已安装APK的移动的逻辑。
对APK进行检查后就会在注释4处调用InstallArgs的copyApk方法进行安装。
不同的InstallArgs子类会有着不同的处理,这里以FileInstallArgs为例。FileInstallArgs的copyApk方法中会直接return FileInstallArgs的doCopyApk方法:
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#FileInstallArgs
private int doCopyApk(IMediaContainerService imcs, boolean temp) throws RemoteException { ... try { final boolean isEphemeral = (installFlags & PackageManager.INSTALL_INSTANT_APP) != 0; //创建临时文件存储目录 final File tempDir = mInstallerService.allocateStageDirLegacy(volumeUuid, isEphemeral);//1 codeFile = tempDir; resourceFile = tempDir; } catch (IOException e) { Slog.w(TAG, "Failed to create copy file: " + e); return PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE; } ... int ret = PackageManager.INSTALL_SUCCEEDED; ret = imcs.copyPackage(origin.file.getAbsolutePath(), target);//2 ... return ret; }
注释1处用于创建临时存储目录,比如/data/app/vmdl18300388.tmp,其中18300388是安装的sessionId。注释2处通过IMediaContainerService跨进程调用DefaultContainerService的copyPackage方法,这个方法会在DefaultContainerService所在的进程中将APK复制到临时存储目录,比如/data/app/vmdl18300388.tmp/base.apk。目前为止APK的复制工作就完成了,接着就是APK的安装过程了。
照例先来查看安装APK的时序图。
image
我们回到APK的复制调用链的头部方法:HandlerParams的startCopy方法,在注释4处会调用handleReturnCode方法,它的实现在InstallParams中,如下所示。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
void handleReturnCode() { if (mArgs != null) { processPendingInstall(mArgs, mRet); } } private void processPendingInstall(final InstallArgs args, final int currentStatus) { mHandler.post(new Runnable() { public void run() { mHandler.removeCallbacks(this); PackageInstalledInfo res = new PackageInstalledInfo(); res.setReturnCode(currentStatus); res.uid = -1; res.pkg = null; res.removedInfo = null; if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) { //安装前处理 args.doPreInstall(res.returnCode);//1 synchronized (mInstallLock) { installPackageTracedLI(args, res);//2 } //安装后收尾 args.doPostInstall(res.returnCode, res.uid);//3 } ... } }); }
handleReturnCode方法中只调用了processPendingInstall方法,注释1处用于检查APK的状态的,在安装前确保安装环境的可靠,如果不可靠会清除复制的APK文件,注释3处用于处理安装后的收尾操作,如果安装不成功,删除掉安装相关的目录与文件。主要来看注释2处的installPackageTracedLI方法,其内部会调用PMS的installPackageLI方法。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void installPackageLI(InstallArgs args, PackageInstalledInfo res) { ... PackageParser pp = new PackageParser(); pp.setSeparateProcesses(mSeparateProcesses); pp.setDisplayMetrics(mMetrics); pp.setCallback(mPackageParserCallback); Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "parsePackage"); final PackageParser.Package pkg; try { //解析APK pkg = pp.parsePackage(tmpPackageFile, parseFlags);//1 } catch (PackageParserException e) { res.setError("Failed parse during installPackageLI", e); return; } finally { Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER); } ... pp = null; String oldCodePath = null; boolean systemApp = false; synchronized (mPackages) { // 检查APK是否存在 if ((installFlags & PackageManager.INSTALL_REPLACE_EXISTING) != 0) { String oldName = mSettings.getRenamedPackageLPr(pkgName);//获取没被改名前的包名 if (pkg.mOriginalPackages != null && pkg.mOriginalPackages.contains(oldName) && mPackages.containsKey(oldName)) { pkg.setPackageName(oldName);//2 pkgName = pkg.packageName; replace = true;//设置标志位表示是替换安装 if (DEBUG_INSTALL) Slog.d(TAG, "Replacing existing renamed package: oldName=" + oldName + " pkgName=" + pkgName); } ... } PackageSetting ps = mSettings.mPackages.get(pkgName); //查看Settings中是否存有要安装的APK的信息,如果有就获取签名信息 if (ps != null) {//3 if (DEBUG_INSTALL) Slog.d(TAG, "Existing package: " + ps); PackageSetting signatureCheckPs = ps; if (pkg.applicationInfo.isStaticSharedLibrary()) { SharedLibraryEntry libraryEntry = getLatestSharedLibraVersionLPr(pkg); if (libraryEntry != null) { signatureCheckPs = mSettings.getPackageLPr(libraryEntry.apk); } } //检查签名的正确性 if (shouldCheckUpgradeKeySetLP(signatureCheckPs, scanFlags)) { if (!checkUpgradeKeySetLP(signatureCheckPs, pkg)) { res.setError(INSTALL_FAILED_UPDATE_INCOMPATIBLE, "Package " + pkg.packageName + " upgrade keys do not match the " + "previously installed version"); return; } } ... } int N = pkg.permissions.size(); for (int i = N-1; i >= 0; i--) { //遍历每个权限,对权限进行处理 PackageParser.Permission perm = pkg.permissions.get(i); BasePermission bp = mSettings.mPermissions.get(perm.info.name); } } } if (systemApp) { if (onExternal) { //系统APP不能在SD卡上替换安装 res.setError(INSTALL_FAILED_INVALID_INSTALL_LOCATION, "Cannot install updates to system apps on sdcard"); return; } else if (instantApp) { //系统APP不能被Instant App替换 res.setError(INSTALL_FAILED_INSTANT_APP_INVALID, "Cannot update a system app with an instant app"); return; } } ... //重命名临时文件 if (!args.doRename(res.returnCode, pkg, oldCodePath)) {//4 res.setError(INSTALL_FAILED_INSUFFICIENT_STORAGE, "Failed rename"); return; } startIntentFilterVerifications(args.user.getIdentifier(), replace, pkg); try (PackageFreezer freezer = freezePackageForInstall(pkgName, installFlags, "installPackageLI")) { if (replace) {//5 //替换安装 ... replacePackageLIF(pkg, parseFlags, scanFlags | SCAN_REPLACING, args.user, installerPackageName, res, args.installReason); } else { //安装新的APK installNewPackageLIF(pkg, parseFlags, scanFlags | SCAN_DELETE_DATA_ON_FAILURES, args.user, installerPackageName, volumeUuid, res, args.installReason); } } synchronized (mPackages) { final PackageSetting ps = mSettings.mPackages.get(pkgName); if (ps != null) { //更新应用程序所属的用户 res.newUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true); ps.setUpdateAvailable(false /*updateAvailable*/); } ... } }
installPackageLI方法的代码有将近500行,这里截取主要的部分,主要做了几件事:
这里我们以新安装APK为例,会调用PMS的installNewPackageLIF方法。
frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void installNewPackageLIF(PackageParser.Package pkg, final int policyFlags, int scanFlags, UserHandle user, String installerPackageName, String volumeUuid, PackageInstalledInfo res, int installReason) { ... try { //扫描APK PackageParser.Package newPackage = scanPackageTracedLI(pkg, policyFlags, scanFlags, System.currentTimeMillis(), user); //更新Settings信息 updateSettingsLI(newPackage, installerPackageName, null, res, user, installReason); if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) { //安装成功后,为新安装的应用程序准备数据 prepareAppDataAfterInstallLIF(newPackage); } else { //安装失败则删除APK deletePackageLIF(pkgName, UserHandle.ALL, false, null, PackageManager.DELETE_KEEP_DATA, res.removedInfo, true, null); } } catch (PackageManagerException e) { res.setError("Package couldn't be installed in " + pkg.codePath, e); } Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER); }
installNewPackageLIF主要做了以下3件事:
安装APK的过程就讲到这里,就不再往下分析下去,有兴趣的同学可以接着深挖。
本文主要讲解了PMS是如何处理APK安装的,主要有几个步骤:
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