Android系统启动篇
4，《Android SystemServer进程启动流程》
Android系统开发准备篇
3，《Android Framework代码IDE加载和调试》
Android系统开发实践篇
4，《android单独编译framework模块并push》
Android系统开发核心知识储备篇
1，《Android编译系统-envsetup和lunch代码篇》
6，《Android中Activity、View和Window关系详解》
11，《android中AMS进程通知Zygote进程fork新进程的通信方式》
Android核心功能详解篇
2，《Android 手势导航（从下往上滑动进入多任务页面）》
3，《android手势分析（应用界面左往右边滑动退出应用）》
———————————————————————————————————————————
目录
一，背景介绍
android的APK安装流程，有四种安装方式：
1，系统应用和预制应用安装，开机时完成，没有安装界面，在PKMS的构造函数中欧冠完成安装
2，网络下载应用安装，通过应用商店来完成，调用PackageManager.installPackages()，有安装界面
3，ADB工具安装，没有安装界面，它通过启动pm脚本的形式，然后调用com.android.commands.pm.Pm类，之后调用到PMS.installStage()完成安装
4，第三方应用安装，通过SD卡里的APK文件安装，有安装界面，由packageinstaller.apk应用处理安装及卸载过程的界面.
均是通过PackageInstallObserver来监听安装是否成功。
二，安装过程
2.1 流程概述
应用安装主要流程：
1，将APK的信息通过IO流的形式写入到PackageInstaller.Session中。
2，调用PackageInstaller.Session的commit方法，将APK的信息交由PKMS处理。
3，拷贝APK
4，最后进行安装
在应用市场点击一个未安装的apk后，发送广播打开PackageInstallerActivity，拉起com.android.packageinstaller（断点的进程）应用，弹出安装界面，这个主要是由bindUi构成，点击之后就会调用startInstall()进行安装。
/PackageInstallerActivity.java
private void bindUi() {
mAlert.setIcon(mAppSnippet.icon);
mAlert.setTitle(mAppSnippet.label);
mAlert.setView(R.layout.install_content_view);
mAlert.setButton(DialogInterface.BUTTON_POSITIVE, getString(R.string.install),
(ignored, ignored2) -> {
if (mOk.isEnabled()) {
if (mSessionId != -1) {
mInstaller.setPermissionsResult(mSessionId, true);
finish();
} else {
//进行APK安装
startInstall();
}
}
}, null);
mAlert.setButton(DialogInterface.BUTTON_NEGATIVE, getString(R.string.cancel),
(ignored, ignored2) -> {
// Cancel and finish
setResult(RESULT_CANCELED);
if (mSessionId != -1) {
//如果mSessionId存在，执行setPermissionsResult()完成取消安装
mInstaller.setPermissionsResult(mSessionId, false);
}
finish();
}, null);
setupAlert();
......
}
//点击”安装“，跳转 InstallInstalling - 开始安装
private void startInstall() {
// Start subactivity to actually install the application
Intent newIntent = new Intent();
newIntent.putExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO, mPkgInfo.applicationInfo);
newIntent.setData(mPackageURI);
newIntent.setClass(this, InstallInstalling.class);
String installerPackageName = getIntent().getStringExtra( Intent.EXTRA_INSTALLER_PACKAGE_NAME);
...
if (installerPackageName != null) {
newIntent.putExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME, installerPackageName);
}
newIntent.addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);
startActivity(newIntent);
finish();
}其中，R.layout.install_content_view布局视图如下：
在startInstall方法组装了一个Intent，并跳转到InstallInstalling这个Activity，并关闭掉当前的PackageInstallerActivity。在InstallInstalling主要用于向包管理器发送包的信息并处理包管理的回调。
2.2 PackageInstaller安装APK
在启动InstallInstalling后，进入onCreate方法:
//InstallInstalling
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ApplicationInfo appInfo = getIntent()
.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO);
mPackageURI = getIntent().getData();
......
setupAlert();
requireViewById(R.id.installing).setVisibility(View.VISIBLE);
if (savedInstanceState != null) {
mSessionId = savedInstanceState.getInt(SESSION_ID);
mInstallId = savedInstanceState.getInt(INSTALL_ID);
try {
//.根据mInstallId向InstallEventReceiver注册一个观察者，launchFinishBasedOnResult会接收到安装事件的回调，无论安装成功或者失败都会关闭当前的Activity(InstallInstalling)。如果savedInstanceState为null，代码的逻辑也是类似的
InstallEventReceiver.addObserver(this, mInstallId,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
// Does not happen
}
} else {
......
File file = new File(mPackageURI.getPath());
try {
PackageParser.PackageLite pkg = PackageParser.parsePackageLite(file, 0);
params.setAppPackageName(pkg.packageName);
params.setInstallLocation(pkg.installLocation);
params.setSize(
PackageHelper.calculateInstalledSize(pkg, false, params.abiOverride));
} catch (PackageParser.PackageParserException e) {
Log.e(LOG_TAG, "Cannot parse package " + file + ". Assuming defaults.");
Log.e(LOG_TAG,
"Cannot calculate installed size " + file + ". Try only apk size.");
params.setSize(file.length());
} catch (IOException e) {
Log.e(LOG_TAG,
"Cannot calculate installed size " + file + ". Try only apk size.");
params.setSize(file.length());
}
try {
//向InstallEventReceiver注册一个观察者返回一个新的mInstallId,
//其中InstallEventReceiver继承自BroadcastReceiver，用于接收安装事件并回调给EventResultPersister。
mInstallId = InstallEventReceiver
.addObserver(this, EventResultPersister.GENERATE_NEW_ID,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
try {
//PackageInstaller的createSession方法内部会通过IPackageInstaller与PackageInstallerService进行进程间通信，最终调用的是PackageInstallerService的createSession方法来创建并返回mSessionId
mSessionId = getPackageManager().getPackageInstaller().createSession(params);
} catch (IOException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
}
mCancelButton = mAlert.getButton(DialogInterface.BUTTON_NEGATIVE);
mSessionCallback = new InstallSessionCallback();
}
}在onCreate中通过PackageInstaller通过创建Session并返回mSesionId，接着会在onResume中，会开启InstallingAsynTask，把包信息写入mSessionId对应的session，然后提交。
//InstallInstalling
protected void onResume() {
super.onResume();
// This is the first onResume in a single life of the activity
if (mInstallingTask == null) {
PackageInstaller installer = getPackageManager().getPackageInstaller();
//获取sessionInfo
PackageInstaller.SessionInfo sessionInfo = installer.getSessionInfo(mSessionId);
if (sessionInfo != null && !sessionInfo.isActive()) {
//创建内部类InstallingAsyncTask的对象，调用execute()，最终进入onPostExecute()
mInstallingTask = new InstallingAsyncTask();
mInstallingTask.execute();
} else {
// we will receive a broadcast when the install is finished
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
}
}
}
private final class InstallingAsyncTask extends AsyncTask<Void, Void,
PackageInstaller.Session> {
@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();
//从session中获取输出流
try (OutputStream out = session
.openWrite("PackageInstaller", 0, sizeBytes)) {
byte[] buffer = new byte[1024 * 1024];
......
}
}
return session;
} catch (IOException | SecurityException e) {
......
}
@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);
//包写入session进行提交
session.commit(pendingIntent.getIntentSender());
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
} else {
getPackageManager().getPackageInstaller().abandonSession(mSessionId);
if (!isCancelled()) {
launchFailure(PackageManager.INSTALL_FAILED_INVALID_APK, null);
}
}
}
}在InstallingAsyncTask的doInBackground()里会根据包的Uri，将APK的信息通过IO流的形式写入到PackageInstaller.Session中，最后会在onPostExecute()中调用PackageInstaller.Session的commit方法，进行安装。
在里面会看到一个PackageInstaller，也就是APK安装器，其实在ApplicationPackageManager的getPackageInstaller中创建的：
//ApplicationPackageManager
@Override
public PackageInstaller getPackageInstaller() {
synchronized (mLock) {
if (mInstaller == null) {
try {
mInstaller = new PackageInstaller(mPM.getPackageInstaller(),
mContext.getPackageName(), getUserId());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
return mInstaller;
}
}在这里会传入mPM.getPackageInstaller()，也就是IpacageInstaller的实例，其具体实现也就是PackageInstallerService， 其通过IPC的方式。它在初始化的时候会读取/data/system目录下的install_sessions文件，这个文件保存了系统未完成的Install Session。PMS则会根据文件的内容创建PackageInstallerSession对象并从插入到mSessions中。
//PackageInstallerService.java
public PackageInstallerService(Context context, PackageManagerService pm,
Supplier<PackageParser2> apexParserSupplier) {
mContext = context;
mPm = pm;
mPermissionManager = LocalServices.getService(PermissionManagerServiceInternal.class);
mInstallThread = new HandlerThread(TAG);
mInstallThread.start();
mInstallHandler = new Handler(mInstallThread.getLooper());
mCallbacks = new Callbacks(mInstallThread.getLooper());
mSessionsFile = new AtomicFile(
new File(Environment.getDataSystemDirectory(), "install_sessions.xml"),
"package-session");
//这个文件保存了系统未完成的`Install Session`
mSessionsDir = new File(Environment.getDataSystemDirectory(), "install_sessions");
mSessionsDir.mkdirs();
mApexManager = ApexManager.getInstance();
mStagingManager = new StagingManager(this, context, apexParserSupplier);
}再来看下Session，是在于mSeesionId绑定的安装会话，代表着一个在进行中的安装。Session类是对IPackageInstaller.openSession(sessionId) 获取的 PackageInstallerSession（系统服务端）的封装。
Session的创建和打开 具体实现是在 PackageInstallerService中，主要是 初始化apk的安装信息及环境，并创建一个sessionId，将安装Session与sessionId 进行绑定.
接着我们回到InstallingAsyncTask中，在这里调用了session.commit方法：
//PackageInstaller
public void commit(@NonNull IntentSender statusReceiver) {
try {
//调用PackageInstallerSession的commit方法,进入到java框架层
mSession.commit(statusReceiver, false);
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
//PackageInstallerSession.java
public void commit(@NonNull IntentSender statusReceiver, boolean forTransfer) {
......
//如果尚未调用，则会话将被密封。此方法可能会被多次调用以更新状态接收者验证调用者权限
if (!markAsSealed(statusReceiver, forTransfer)) {
return;
}
//不同的包
if (isMultiPackage()) {
final SparseIntArray remainingSessions = mChildSessionIds.clone();
final IntentSender childIntentSender =
new ChildStatusIntentReceiver(remainingSessions, statusReceiver)
.getIntentSender();
boolean sealFailed = false;
for (int i = mChildSessionIds.size() - 1; i >= 0; --i) {
final int childSessionId = mChildSessionIds.keyAt(i);
// seal all children, regardless if any of them fail; we'll throw/return
// as appropriate once all children have been processed
if (!mSessionProvider.getSession(childSessionId)
.markAsSealed(childIntentSender, forTransfer)) {
sealFailed = true;
}
}
if (sealFailed) {
return;
}
}
dispatchStreamValidateAndCommit();
}
private void dispatchStreamValidateAndCommit() {
mHandler.obtainMessage(MSG_STREAM_VALIDATE_AND_COMMIT).sendToTarget();
}mSession的类型为IPackageInstallerSession，这说明要通过IPackageInstallerSession来进行进程间的通信，最终会调用PackageInstallerSession的commit方法。 在这里发送了一个MSG_STREAM_VALIDATE_AND_COMMIT的信号，并在handler中进行处理：
public boolean handleMessage(Message msg) {
case MSG_STREAM_VALIDATE_AND_COMMIT:
handleStreamValidateAndCommit();
break;
case MSG_INSTALL:
handleInstall(); //
break;
......
}
private void handleStreamValidateAndCommit() {
......
if (unrecoverableFailure != null) {
onSessionVerificationFailure(unrecoverableFailure);
// fail other child sessions that did not already fail
for (int i = nonFailingSessions.size() - 1; i >= 0; --i) {
PackageInstallerSession session = nonFailingSessions.get(i);
session.onSessionVerificationFailure(unrecoverableFailure);
}
}
}
if (!allSessionsReady) {
return;
}
mHandler.obtainMessage(MSG_INSTALL).sendToTarget();
}在handleStreamValidateAndCommit又发送了消息MSG_INSTALL,实际上真正在执行的是在handleInstall中:
private void handleInstall() {
......
// 对于 multiPackage 会话，请在锁之外读取子会话，因为在持有锁的情况下读取子会话可能会导致死锁 (b123391593)。
List<PackageInstallerSession> childSessions = getChildSessionsNotLocked();
try {
synchronized (mLock) {
installNonStagedLocked(childSessions);
}
} catch (PackageManagerException e) {
final String completeMsg = ExceptionUtils.getCompleteMessage(e);
Slog.e(TAG, "Commit of session " + sessionId + " failed: " + completeMsg);
destroyInternal();
dispatchSessionFinished(e.error, completeMsg, null);
}
}
private void installNonStagedLocked(List<PackageInstallerSession> childSessions)
throws PackageManagerException {
......
if (!success) {
sendOnPackageInstalled(mContext, mRemoteStatusReceiver, sessionId,
isInstallerDeviceOwnerOrAffiliatedProfileOwnerLocked(), userId, null,
failure.error, failure.getLocalizedMessage(), null);
return;
}
mPm.installStage(installingChildSessions);
} else {
mPm.installStage(installingSession);
}
}最后执行到了PMS的installStage方法。在上述的过程中，通过PackageInstaller维持了Session，把安装包写入到Session，真正的安装过程就要来看PMS了。
2.3 PMS执行安装
//PackageManagerService.java
void installStage(List<ActiveInstallSession> children)
throws PackageManagerException {
//创建了类型未INIT_COPY的消息
final Message msg = mHandler.obtainMessage(INIT_COPY);
//创建InstallParams，它对应于包的安装数据
final MultiPackageInstallParams params =
new MultiPackageInstallParams(UserHandle.ALL, children);
params.setTraceMethod("installStageMultiPackage")
.setTraceCookie(System.identityHashCode(params));
msg.obj = params;
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "installStageMultiPackage",
System.identityHashCode(msg.obj));
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "queueInstall",
System.identityHashCode(msg.obj));
//将InstallParams通过消息发送出去
mHandler.sendMessage(msg);
}
handler对INIT_COPY的消息进行处理：
//PackageManagerService.java
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");
//执行APK拷贝动作
params.startCopy();
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
break;
}
......
}
final void startCopy() {
if (DEBUG_INSTALL) Slog.i(TAG, "startCopy " + mUser + ": " + this);
handleStartCopy();
handleReturnCode();
} 在这里调用了两个方法handleStartCopy和handleReturnCode,其实现是在InstallParams 中。
在handleStartCopy,做了以下操作：
- 检查空间大小，如果空间不够则释放无用空间
- 覆盖原有安装位置的文件，并根据返回结果来确定函数的返回值，并设置installFlags
- 确定是否有任何已安装的包验证器，如有，则延迟检测。主要分三步：首先新建一个验证Intent，然后设置相关的信息，之后获取验证器列表，最后向每个验证器发送验证Intent
public void handleStartCopy() {
......
//解析包 返回最小的细节:pkgName、versionCode、安装所需空间大小、获取安装位置等
pkgLite = PackageManagerServiceUtils.getMinimalPackageInfo(mContext,
origin.resolvedPath, installFlags, packageAbiOverride);
......
//覆盖原有安装位置的文件，并根据返回结果来确定函数的返回值，并设置installFlags。
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 {
.......
}
}
//安装参数
final InstallArgs args = createInstallArgs(this);
mVerificationCompleted = true;
mIntegrityVerificationCompleted = true;
mEnableRollbackCompleted = true;
mArgs = args;
if (ret == PackageManager.INSTALL_SUCCEEDED) {
final int verificationId = mPendingVerificationToken++;
// apk完整性校验
if (!origin.existing) {
PackageVerificationState verificationState =
new PackageVerificationState(this);
mPendingVerification.append(verificationId, verificationState);
sendIntegrityVerificationRequest(verificationId, pkgLite, verificationState);
ret = sendPackageVerificationRequest(
verificationId, pkgLite, verificationState);
......
}
}然后来看下handleReturnCode方法：
@Override
void handleReturnCode() {
......
if (mRet == PackageManager.INSTALL_SUCCEEDED) {
//执行APKcopy拷贝
mRet = mArgs.copyApk();
}
//执行安装
processPendingInstall(mArgs, mRet);
}
}APK的copy过程是如何拷贝的：
//packageManagerService.java
int copyApk() {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "copyApk");
try {
return doCopyApk();
} finally {
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
}
private int doCopyApk() {
......
int ret = PackageManagerServiceUtils.copyPackage(
origin.file.getAbsolutePath(), codeFile);
......
return ret;
}
//继续追踪下去，他会到PackagemanagerSeriveUtils的copyFile方法
//PackagemanagerSeriveUtils
private static void copyFile(String sourcePath, File targetDir, String targetName)
throws ErrnoException, IOException {
if (!FileUtils.isValidExtFilename(targetName)) {
throw new IllegalArgumentException("Invalid filename: " + targetName);
}
Slog.d(TAG, "Copying " + sourcePath + " to " + targetName);
final File targetFile = new File(targetDir, targetName);
final FileDescriptor targetFd = Os.open(targetFile.getAbsolutePath(),
O_RDWR | O_CREAT, 0644);
Os.chmod(targetFile.getAbsolutePath(), 0644);
FileInputStream source = null;
try {
source = new FileInputStream(sourcePath);
FileUtils.copy(source.getFD(), targetFd);
} finally {
IoUtils.closeQuietly(source);
}
}在这里就通过文件流的操作，把Apk拷贝到/data/app的目录下了。结束完拷贝之后，就要进入真正的安装了，流程如下：
/PackageManagerService.java
private void processPendingInstall(final InstallArgs args, final int currentStatus) {
if (args.mMultiPackageInstallParams != null) {
args.mMultiPackageInstallParams.tryProcessInstallRequest(args, currentStatus);
} else {
//安装结果
PackageInstalledInfo res = createPackageInstalledInfo(currentStatus);
//创建一个新线程来处理安转参数来进行安装
processInstallRequestsAsync(
res.returnCode == PackageManager.INSTALL_SUCCEEDED,
Collections.singletonList(new InstallRequest(args, res)));
}
}
//排队执行异步操作
private void processInstallRequestsAsync(boolean success,
List<InstallRequest> installRequests) {
mHandler.post(() -> {
if (success) {
for (InstallRequest request : installRequests) {
//进行检验，如果之前安装失败，则清除无用信息
request.args.doPreInstall(request.installResult.returnCode);
}
synchronized (mInstallLock) {
//安装的核心方法，进行解析apk安装
installPackagesTracedLI(installRequests);
}
for (InstallRequest request : installRequests) {
//再次检验清除无用信息
request.args.doPostInstall(
request.installResult.returnCode, request.installResult.uid);
}
}
for (InstallRequest request : installRequests) {
//备份、可能的回滚、发送安装完成先关广播
restoreAndPostInstall(request.args.user.getIdentifier(), request.installResult,
new PostInstallData(request.args, request.installResult, null));
}
});
}看到了核心方法installPackagesTracedLI,接着内部执行到了installPackagesLI方法：
//PackageMmanagerSerice.java
private void installPackagesLI(List<InstallRequest> requests) {
.......
//分析当前任何状态，分析包并对其进行初始化验证
prepareResult =
preparePackageLI(request.args, request.installResult);
......
//根据准备阶段解析包的信息上下文，进一步解析
final ScanResult result = scanPackageTracedLI(
prepareResult.packageToScan, prepareResult.parseFlags,
prepareResult.scanFlags, System.currentTimeMillis(),
request.args.user, request.args.abiOverride);
.......
//验证扫描后包的信息好状态，确保安装成功
reconciledPackages = reconcilePackagesLocked(
reconcileRequest, mSettings.mKeySetManagerService);
//提交所有的包并更新系统状态。这是安装流中唯一可以修改系统状态的地方，必须在此阶段之前确定所有可预测的错误
commitRequest = new CommitRequest(reconciledPackages,
mUserManager.getUserIds());
commitPackagesLocked(commitRequest);
.......
//完成APK安装
executePostCommitSteps(commitRequest);
}由上面代码可知，installPackagesLI主要做了以下事情：
- 分析当前任何状态，分析包并对其进行初始化验证
- 根据准备阶段解析包的信息上下文，进一步解析
- 验证扫描后包的信息好状态，确保安装成功
- 提交所有骚哦欧庙的包并更新系统状态
- 完成APK安装
在 preparePackageLI() 内使用 PackageParser2.parsePackage() 解析AndroidManifest.xml，获取四大组件等信息；使用ParsingPackageUtils.getSigningDetails() 解析签名信息；重命名包最终路径 等。
完成了解析和校验准备工作后，最后一步就是对apk的安装了。这里调用了executePostCommitSteps准备app数据，并执行dex优化。
//PackageManagerService.java
private void executePostCommitSteps(CommitRequest commitRequest) {
//进行安装
prepareAppDataAfterInstallLIF(pkg);
.......
final boolean performDexopt =
(!instantApp || Global.getInt(mContext.getContentResolver(),
Global.INSTANT_APP_DEXOPT_ENABLED, 0) != 0)
&& !pkg.isDebuggable()
&& (!onIncremental);
//为新的代码路径准备应用程序配置文件
mArtManagerService.prepareAppProfiles(
pkg,
resolveUserIds(reconciledPkg.installArgs.user.getIdentifier()),
if (performDexopt) {
......
//其中分配了 dexopt 所需的库文件
PackageSetting realPkgSetting = result.existingSettingCopied
? result.request.pkgSetting : result.pkgSetting;
if (realPkgSetting == null) {
realPkgSetting = reconciledPkg.pkgSetting;
}
//执行dex优化
mPackageDexOptimizer.performDexOpt(pkg, realPkgSetting,
null /* instructionSets */,
getOrCreateCompilerPackageStats(pkg),
mDexManager.getPackageUseInfoOrDefault(packageName),
dexoptOptions);
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
}在prepareAppDataAfterInstallLIF方法中，经过一系列的调用，最中会调用到 mInstaller.createAppData，这里也是调用Installd守护进程的入口:
public class Installer extends SystemService {
@Override
public void onStart() {
if (mIsolated) {
mInstalld = null;
} else {
//通过Binder调用到进程installd
connect();
}
}
private void connect() {
IBinder binder = ServiceManager.getService("installd");
......
if (binder != null) {
mInstalld = IInstalld.Stub.asInterface(binder);
try {
invalidateMounts();
} catch (InstallerException ignored) {
}
} else {
Slog.w(TAG, "installd not found; trying again");
BackgroundThread.getHandler().postDelayed(() -> {
connect();
}, DateUtils.SECOND_IN_MILLIS);
}
}
public long createAppData(String uuid, String packageName, int userId, int flags, int appId,
String seInfo, int targetSdkVersion) throws InstallerException {
if (!checkBeforeRemote()) return -1;
try {
//进行安装操作
return mInstalld.createAppData(uuid, packageName, userId, flags, appId, seInfo,
targetSdkVersion);
} catch (Exception e) {
throw InstallerException.from(e);
}
}
}可以看到最终调用了Installd的createAppData方法进行安装。Installer是Java层提供的Java API接口，Installd 则是在init进程启动的具有root权限的Daemon进程。
在processInstallRequestsAsync最后一步时调用了restoreAndPostInstall,在安装完成时会发送POST_INSTALL消息：
//PackageManagerService.java
private void restoreAndPostInstall(
int userId, PackageInstalledInfo res, @Nullable PostInstallData data) {
.......
if (!doRestore) {
if (DEBUG_INSTALL) Log.v(TAG, "No restore - queue post-install for " + token);
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "postInstall", token);
Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0);
mHandler.sendMessage(msg);
}
}
void doHandleMessage(Message msg) {
.......
case POST_INSTALL: {
.......
//处理安装结果
handlePackagePostInstall(parentRes, grantPermissions,
killApp, virtualPreload, grantedPermissions,
whitelistedRestrictedPermissions, autoRevokePermissionsMode,
didRestore, args.installSource.installerPackageName, args.observer,
args.mDataLoaderType);
}
}
private void handlePackagePostInstall(PackageInstalledInfo res, boolean grantPermissions,
boolean killApp, boolean virtualPreload,
String[] grantedPermissions, List<String> whitelistedRestrictedPermissions,
int autoRevokePermissionsMode,
boolean launchedForRestore, String installerPackage,
IPackageInstallObserver2 installObserver, int dataLoaderType) {
......
sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED, packageName,
extras, 0 /*flags*/,
null /*targetPackage*/, null /*finishedReceiver*/,
updateUserIds, instantUserIds, newBroadcastWhitelist);
}最后发送了ACTION_PACKAGE_ADDED广播，launcher接收到这个广播之后就会在桌面上添加应用图标了。