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前言
前面一篇文章我们讲解了PKMS的启动过程。
PKMS启动过程中主要做了以下事情：
- 1.会对某些配置文件进行解析扫描，放到PKMS对象内存中
- 2.会对系统中的应用包括：overlay，system，vendor，app等路径下的应用进行扫描，如果发现有版本更新，则进行应用更新操作。
- 3.初始化包管理过程中需要使用到一些环境对象等。
接下面我们再来讲解下第三方应用的安装过程
应用安装过程
应用安装的方式有如下几种：
1.普通安装方式
在7.0之后，为了进一步提升文件读写的安全性，Android框架执行的StrictMode API政策禁止在您的应用外部公开file://URI。 如果一项包含文件URI的intent离开您的应用，则应用出现故障，并出现FileUriExposedException异常。
这个时候需要使用FileProvider来授权外部文件读写权限。
FileProvider
具体使用方式如下：
1.在AndroidManifest文件中定义：
<provider android:authorities="${applicationId}.fileprovider" android:name="androidx.core.content.FileProvider" android:exported="false" android:grantUriPermissions="true" > <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/update_files" /> </provider>2.在xml中定义文件update_files.xml：
<?xml version="1.0" encoding="utf-8"?> <paths xmlns:android="http://schemas.android.com/apk/res/android"> <external-path name="external_storage_install" path="yuhb/install"/> </paths>3.在代码中调用
/** 普通应用安装方式 7.0以后需要使用FileProvider进行申请 @param apkFile @param context */ public static void generateInstall(File apkFile, Context context){ if(!apkFile.exists()){ return; } Intent intent = getInstallIntent(apkFile, context); context.startActivity(intent); } //获取安装应用的Intent private static Intent getInstallIntent(File apkFile, Context context) { Uri data; Intent intent = new Intent(Intent.ACTION_VIEW); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); data = getInstallUri(context,apkFile); //7.0以后使用FileProvider处理 if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.N){ intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);//授权其他应用的读权限 intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);//防止app加固下出现授权失败情况 // intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);//授权其他应用写权限 } intent.setDataAndType(data,"application/vnd.android.package-archive"); return intent; } //获取安装文件的uri private static Uri getInstallUri(Context context,File apkFile) { Uri data; //7.0以后使用FileProvider处理 if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.N){ data = FileProvider.getUriForFile(context,context.getPackageName()+".fileprovider",apkFile); }else { data = Uri.fromFile(apkFile); } return data; }
2.静默安装方式（需要有root权限）
你是不是尝试了N种方法，打了N个debug，然后得到的却是各种各样的安装失败 ~ 首先类似静默功能一般是被系统所禁止的，只有厂商在自已平台才会开发权限（好比小米的系统应用，默认实现了静默功能，但是如果小米应用移植到vivo就无效了）。
具体使用方式如下：
/**静默安装方式，一般需要root权限或者是厂商自己的系统应用。
@param context
@param apkFilePath
*/
public static void silenceInstallApk(Context context,String apkFilePath) {
/*apkFilePath:这里我们首先传入的是安装包的路径 installObserver:自定义安装的回调，不需要可以删了*/
File apkFile = new File(apkFilePath);
//判断路径下的文件是否存在
if (!apkFile.exists()) {
Log.e(TAG, "apkFile is null...");
return;
}
String packageName = "";
//获取安装包的信息
PackageInfo packageInfo = context.getPackageManager().getPackageArchiveInfo(apkFilePath,
PackageManager.GET_ACTIVITIES | PackageManager.GET_SERVICES);
if (packageInfo != null) {
packageName = packageInfo.packageName;
String versionName = packageInfo.versionName;
}
//获取packageInstaller，后面用来创建PackageInstaller.Session
PackageInstaller packageInstaller = context.getPackageManager().getPackageInstaller();
//获取创建PackageInstaller.Session的参数
PackageInstaller.SessionParams sessionParams = new PackageInstaller.SessionParams(
PackageInstaller.SessionParams.MODE_FULL_INSTALL);
/*指示将在此会话中交付的所有APK的总大小（以字节为单位），系统可以使用它来确保在继续之前存在足够的磁盘空间，
或者估计安装在外部存储上的容器大小*/
sessionParams.setSize(apkFile.length());
PackageInstaller.Session session = null;
try {
//代表一个session的唯一ID,这里我是在全局变量中声明，因为后面的另外一个方法用到了这个sessionId
int mSessionId = packageInstaller.createSession(sessionParams);
if (mSessionId != -1) {
//也就是在这个外部的onTransfesApkFile()方法中，将会用到sessionId
boolean copySuccess = onTransfesApkFile(mSessionId,context,apkFilePath, packageName);
if (copySuccess) {
session = context.getPackageManager().getPackageInstaller().openSession(mSessionId);
//设置安装完成后需要发送的一个自定义安装结果广播，这里我设置了App的NAME，VERSION，PACKAGE
Intent intent = new Intent(context,
InstallResultReceiver.class);
intent.setAction(PackageInstaller.EXTRA_STATUS);
intent.putExtra("APP_VERSION", "1.0");
intent.putExtra("APP_PACKAGE", "com.allinpay.manager");
//执行结束后，发送intent
PendingIntent pendingIntent = PendingIntent.getBroadcast(context,1,
intent, PendingIntent.FLAG_UPDATE_CURRENT);
//这里最终进行session的提交
session.commit(pendingIntent.getIntentSender());
} else {
//此处是安装失败的回调，不需要可以删除
// if (installObserver != null) {
// installObserver.observer(false, apkFilePath, packageName);
// }
}
}
} catch (Exception exception) {
Log.e(TAG, "installApk exception = " + exception.getLocalizedMessage());
} finally {
if (null != session) {
session.close();
}
//安装完成需要删除文件
if (apkFile != null && apkFile.exists()) {
// apkFile.delete();
}
}
}
private static boolean onTransfesApkFile(int mSessionId,Context context,String apkFilePath, String packageName) {
InputStream in = null;
OutputStream out = null;
PackageInstaller.Session session = null;
boolean success = false;
try {
File apkFile = new File(apkFilePath);
//根据sessionId来获取其代表的session
session = context.getPackageManager().getPackageInstaller().openSession(mSessionId);
//向session中写入文件数据
out = session.openWrite(packageName + "_base.apk", 0, apkFile.length());
in = new FileInputStream(apkFile);
int total = 0;
int len;
byte[] buffer = new byte[1024];
while ((len = in.read(buffer)) != -1) {
total += len;
out.write(buffer, 0, len);
}
session.fsync(out);
success = true;
} catch (IOException exception) {
exception.printStackTrace();
} finally {
if (null != session) {
session.close();
}
try {
if (null != out) {
out.close();
}
if (null != in) {
in.close();
}
} catch (IOException exception) {
exception.printStackTrace();
}
}
return success;
}这里我们来分析下方式一（普通应用更新方式）
1.提取关键代码：调用的startActivity中的Intent属性
Action：Intent.ACTION_VIEWFlag：Intent.FLAG_ACTIVITY_NEW_TASKUri：content格式Type：application/vnd.android.package-archive
2.根据以上Intent，调用了startActivity，然后通过PKMS找到对应的Activity。 最终定位到：InstallStart类，这个类就是启动安装时打开的第一个Activity。
/** Select which activity is the first visible activity of the installation and forward the intent to it. */ public class InstallStart extends Activity { protected void onCreate(@Nullable Bundle savedInstanceState) { ... Uri packageUri = intent.getData(); //如果Scheme是Content格式 if (packageUri != null && packageUri.getScheme().equals( ContentResolver.SCHEME_CONTENT)) { // [IMPORTANT] This path is deprecated, but should still work. Only necessary // features should be added.// Copy file to prevent it from being changed underneath this process nextActivity.setClass(this, InstallStaging.class); //如果Scheme是package格式 } else if (packageUri != null && packageUri.getScheme().equals( PackageInstallerActivity.SCHEME_PACKAGE)) { nextActivity.setClass(this, PackageInstallerActivity.class); //如果Scheme是其他格式 } else { Intent result = new Intent(); result.putExtra(Intent.EXTRA_INSTALL_RESULT, PackageManager.INSTALL_FAILED_INVALID_URI); setResult(RESULT_FIRST_USER, result); nextActivity = null; } if (nextActivity != null) { startActivity(nextActivity); } finish();}
}
InstallStart的onCreate方法会对传入的Scheme格式进行判断，然后启动另外一个Activity，并结束自己。 我们重点来看Content格式的Activity。最终启动的是InstallStaging.class。看父类名字应该是一个选择框类型的Activity。
//frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/InstallStaging.java
public class InstallStaging extends AlertActivity {
protected void onResume() {
...
mStagingTask = new StagingAsyncTask();
//执行StagingAsyncTask
mStagingTask.execute(getIntent().getData());
}
private final class StagingAsyncTask extends AsyncTask<Uri, Void, Boolean> {
@Override
protected Boolean doInBackground(Uri... params) {
if (params == null || params.length <= 0) {
return false;
}
Uri packageUri = params[0];
try (InputStream in = getContentResolver().openInputStream(packageUri)) {
// Despite the comments in ContentResolver#openInputStream the returned stream can
// be null.
if (in == null) {
return false;
}
try (OutputStream out = new FileOutputStream(mStagedFile)) {
byte[] buffer = new byte[1024 * 1024];
int bytesRead;
while ((bytesRead = in.read(buffer)) >= 0) {
// Be nice and respond to a cancellation
if (isCancelled()) {
return false;
}
out.write(buffer, 0, bytesRead);
}
}
} catch (IOException | SecurityException | IllegalStateException e) {
Log.w(LOG_TAG, "Error staging apk from content URI", e);
return false;
}
return true;
}
@Override
protected void onPostExecute(Boolean success) {
if (success) {
// Now start the installation again from a file
Intent installIntent = new Intent(getIntent());
installIntent.setClass(InstallStaging.this, DeleteStagedFileOnResult.class);
installIntent.setData(Uri.fromFile(mStagedFile));
if (installIntent.getBooleanExtra(Intent.EXTRA_RETURN_RESULT, false)) {
installIntent.addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);
}
installIntent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivity(installIntent);
InstallStaging.this.finish();
} else {
showError();
}
}
}
}- 1.InstallStaging的onResume时会启用了一个ASyncTask，在后台读取apk文件，并写入到mStagedFile文件中。 mStagedFile文件的作用是临时文件，防止在安装过程中对原文件变更。
- 2.在文件读取完成后，调用AsyncTask的onPostExecute方法，这个方法中会再次启动一个DeleteStagedFileOnResult类Activity。
继续进入DeleteStagedFileOnResult
/**
* Trampoline activity. Calls PackageInstallerActivity and deletes staged install file onResult.
*/
public class DeleteStagedFileOnResult extends Activity {
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
Intent installIntent = new Intent(getIntent());
installIntent.setClass(this, PackageInstallerActivity.class);
installIntent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivityForResult(installIntent, 0);
}
}看谷歌给我们的注解：这个类是一个过渡Activity：最终是用来启动PackageInstallerActivity并删除mStagedFile临时文件，这在onCreate方法中也可以看出。
那就转到PackageInstallerActivity，在PackageInstallerActivity中会让引导用户点击安装按钮，点击之后会调用startInstall方法进行安装操作。
//frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/PackageInstallerActivity.java
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 (mOriginatingURI != null) {
newIntent.putExtra(Intent.EXTRA_ORIGINATING_URI, mOriginatingURI);
}
if (mReferrerURI != null) {
newIntent.putExtra(Intent.EXTRA_REFERRER, mReferrerURI);
}
if (mOriginatingUid != PackageInstaller.SessionParams.UID_UNKNOWN) {
newIntent.putExtra(Intent.EXTRA_ORIGINATING_UID, mOriginatingUid);
}
if (installerPackageName != null) {
newIntent.putExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME,
installerPackageName);
}
if (getIntent().getBooleanExtra(Intent.EXTRA_RETURN_RESULT, false)) {
newIntent.putExtra(Intent.EXTRA_RETURN_RESULT, true);
}
newIntent.addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);
if (mLocalLOGV) Log.i(TAG, "downloaded app uri=" + mPackageURI);
startActivity(newIntent);
finish();
}startInstall重新启动了一个“InstallInstalling”去安装，并将启动应用需要的参数信息放到Intent中。
//frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/InstallInstalling.java
public class InstallInstalling extends AlertActivity {
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
PackageInstaller.SessionParams params = new PackageInstaller.SessionParams(
PackageInstaller.SessionParams.MODE_FULL_INSTALL);
...
//注册一个安装结果监听器launchFinishBasedOnResult
mInstallId = InstallEventReceiver
.addObserver(this, EventResultPersister.GENERATE_NEW_ID,
this::launchFinishBasedOnResult);
...
//创建一个createSession
mSessionId = getPackageManager().getPackageInstaller().createSession(params);
}
@Override
protected void onResume() {
//启动一个InstallingAsyncTask
mInstallingTask = new InstallingAsyncTask();
mInstallingTask.execute();
}
private final class InstallingAsyncTask extends AsyncTask<Void, Void,
PackageInstaller.Session> {
@Override
protected PackageInstaller.Session doInBackground(Void... params) {
PackageInstaller.Session session;
try {
//打开Session
session = getPackageManager().getPackageInstaller().openSession(mSessionId);
} catch (IOException e) {
}
//设置session安装进度
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) {
}
}
@Override
protected void onPostExecute(PackageInstaller.Session session) {
if (session != null) {
//注册一个broadcastIntent监听安装结果：BROADCAST_ACTION = "com.android.packageinstaller.ACTION_INSTALL_COMMIT";
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 | PendingIntent.FLAG_MUTABLE);
//调用commit进行安装
session.commit(pendingIntent.getIntentSender());
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
}
}
}
}
}InstallInstalling可以总结为下面几个步骤：
- 1.创建session
- 2.打开session
- 3.copy apk文件到Session中
- 4.调用commit进行安装。
仔细观察你会发现：这里步骤和我们前面分析的静默安装方式步骤其实是一样的。而我们的InstallInstalling是运行在系统进程中，所以拥有静默安装权限， 而第三方应用是没有这个权限的、
下面我们深入PackageInstaller看看其是如何实现安装过程的？
首先来看context.getPackageManager().getPackageInstaller()获取到的是哪个类？
如果你对Activity熟悉的话，应该知道context的实现类是ContextImpl类。
定位到它的getPackageManager。
//frameworks/base/core/java/android/app/ContextImpl.java
public PackageManager getPackageManager() {
if (mPackageManager != null) {
return mPackageManager;
}
final 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;
}由此可知getPackageManager返回的是一个ApplicationPackageManager，而这里有个关键参数pm，后期操作实际都是通过pm进行的。 pm是通过ActivityThread.getPackageManager()获取。
//frameworks/base/core/java/android/app/ActivityThread.java
public static IPackageManager getPackageManager() {
if (sPackageManager != null) {
return sPackageManager;
}
final IBinder b = ServiceManager.getService("package");
sPackageManager = IPackageManager.Stub.asInterface(b);
return sPackageManager;
}哦？原来就是获取ServiceManager中的package服务。如果你还有印象，前面我们分析过在PKMS的main方法中有下面这段代码。
//构造IPackageManagerImpl对象并将其add到ServiceManager中：name为package
IPackageManagerImpl iPackageManager = m.new IPackageManagerImpl();
ServiceManager.addService("package", iPackageManager);所以这里返回的是一个IPackageManagerImpl对象。
好了，回到前面context.getPackageManager().getPackageInstaller()
context.getPackageManager()：对应ApplicationPackageManager(context,IPackageManagerImpl)
进入ApplicationPackageManager的getPackageInstaller：
//frameworks/base/core/java/android/app/ApplicationPackageManager.java
public PackageInstaller getPackageInstaller() {
if (mInstaller == null) {
try {
mInstaller = new PackageInstaller(mPM.getPackageInstaller(),
mContext.getPackageName(), mContext.getAttributionTag(), getUserId());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
return mInstaller;
}由此可知getPackageInstaller返回的是一个PackageInstaller对象，而关键看第一个参数mPM.getPackageInstaller()，这个参数也是实际进行安装的类。
前面分析过mPM是IPackageManagerImpl对象，进入IPackageManagerImpl.getPackageInstaller()
在IPackageManagerImpl父类IPackageManagerBase实现了getPackageInstaller
//frameworks/base/services/core/java/com/android/server/pm/IPackageManagerBase.java
public final IPackageInstaller getPackageInstaller() {
...
return mInstallerService;
}返回的是一个mInstallerService，这个mInstallerService是在哪里赋值的呢？经过几轮跳转，定位到。
mInstallerService是在PKMS的构造方法中赋值的：mInstallerService = mInjector.getPackageInstallerService();
mInjector是PackageManagerServiceInjector类（PKMS的运行时环境类）。
最终获取的mInstallerService是在PKMS构造过程中也就是系统开机时初始化的PackageInstallerService对象。
好了这里画了一张图来表示他们之间的关系：
由以上分析可知：context.getPackageManager().getPackageInstaller()获取的是PackageInstaller，而实际安装操作是PackageInstaller的内部PackageInstallerService对象
下面我们根据前面分析出的安装步骤进行具体分析 1.创建session 2.打开session 3.copy apk文件到Session中 4.调用commit进行安装。
1.创建session
//frameworks/base/core/java/android/content/pm/PackageInstaller.java
public int createSession(@NonNull SessionParams params) throws IOException {
//mInstaller为PackageInstallerService
return mInstaller.createSession(params, mInstallerPackageName, mAttributionTag,
mUserId);
}
PackageInstallerService的createSession方法会调用内置的createSessionInternal方法
private int createSessionInternal(SessionParams params, String installerPackageName...){
//前面一大堆对Session创建的条件进行判断，不满足创建则抛出异常
//创建随机数的sessionId
sessionId = allocateSessionIdLocked();
//创建SessionDir
stageDir = buildSessionDir(sessionId, params);
//InstallSource持有应用安装的apk源文件信息
InstallSource installSource = InstallSource.create(installerPackageName,
originatingPackageName, requestedInstallerPackageName,
installerAttributionTag, params.packageSource);
//创建session ： PackageInstallerSession
session = new PackageInstallerSession(mInternalCallback, mContext, mPm, this,
mSilentUpdatePolicy, mInstallThread.getLooper(), mStagingManager, sessionId,
userId, callingUid, installSource, params, createdMillis, 0L, stageDir, stageCid,
null, null, false, false, false, false, null, SessionInfo.INVALID_ID,
false, false, false, PackageManager.INSTALL_UNKNOWN, "");
//将session放入到mSessions键值对中，key为sessionId
synchronized (mSessions) {
mSessions.put(sessionId, session);
}
//将InstallSource放入到PKMS的Setting集合中
mPm.addInstallerPackageName(session.getInstallSource());
}createSessionInternal过程主要就是创建了PackageInstallerSession对象，并将对象放入到mSessions集合中。
2.打开session
打开Session也是调用PackageInstallerService的createSession方法，内部调用openSessionInternal进行打开。
private IPackageInstallerSession openSessionInternal(int sessionId) throws IOException {
synchronized (mSessions) {
final PackageInstallerSession session = mSessions.get(sessionId);
if (!checkOpenSessionAccess(session)) {
throw new SecurityException("Caller has no access to session " + sessionId);
}
session.open();
return session;
}
}内容很简单，通过sessionId去mSessions获取Session对象，然后调用session.open()打开。
//frameworks/base/services/core/java/com/android/server/pm/PackageInstallerSession.java
public void open() throws IOException {
...
boolean wasPrepared;
synchronized (mLock) {
wasPrepared = mPrepared;
if (!mPrepared) {
if (stageDir != null) {
prepareStageDir(stageDir);
}
mPrepared = true;
}
}
}
static void prepareStageDir(File stageDir) throws IOException {
try {
Os.mkdir(stageDir.getAbsolutePath(), 0775);
Os.chmod(stageDir.getAbsolutePath(), 0775);
} catch (ErrnoException e) {
}
}open方法也只是调用Os的mkdir进行stageDir文件夹创建，并且给stageDir文件夹设置了对应的权限、 stageDir临时文件夹路径：new File("data/app", "vmdl" + sessionId + ".tmp");
3.copy apk文件到Session中
Session文件的写操作openWrite最终调用的是PackageInstallerSession的doWriteInternal，写文件就不介绍了，这个大家都非常清楚了。 只要知道文件是写入到的是stageDir临时文件夹("data/app/vmdl{$sessionId}.tmp")下面
4.调用commit进行安装。
public void commit(@NonNull IntentSender statusReceiver, boolean forTransfer) {
...
dispatchSessionSealed();
}
private void dispatchSessionSealed() {
mHandler.obtainMessage(MSG_ON_SESSION_SEALED).sendToTarget();
}
private final Handler.Callback mHandlerCallback = new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case MSG_ON_SESSION_SEALED:
//内部发射一个MSG_STREAM_VALIDATE_AND_COMMIT msg
handleSessionSealed();
break;
case MSG_STREAM_VALIDATE_AND_COMMIT:
//内部发射一个MSG_INSTALL msg
handleStreamValidateAndCommit();
break;
case MSG_INSTALL:
//处理应用安装过程
handleInstall();
break;
case MSG_ON_PACKAGE_INSTALLED:
final SomeArgs args = (SomeArgs) msg.obj;
final String packageName = (String) args.arg1;
final String message = (String) args.arg2;
final Bundle extras = (Bundle) args.arg3;
final IntentSender statusReceiver = (IntentSender) args.arg4;
final int returnCode = args.argi1;
args.recycle();
sendOnPackageInstalled(mContext, statusReceiver, sessionId,
isInstallerDeviceOwnerOrAffiliatedProfileOwner(), userId,
packageName, returnCode, message, extras);
break;
case MSG_SESSION_VALIDATION_FAILURE:
final int error = msg.arg1;
final String detailMessage = (String) msg.obj;
onSessionValidationFailure(error, detailMessage);
break;
}
return true;
}
};发送MSG_ON_SESSION_SEALED的msg调用handleSessionSealed方法。handleSessionSealed方法内部又发送了MSG_STREAM_VALIDATE_AND_COMMIT的msg。 然后在handleStreamValidateAndCommit又发送了MSG_INSTALL。所以最终调用了handleInstall方法进行安装。
handleInstall方法可以大致分为：
- 1.apk文件的校验
- 2.apk文件的安装
@WorkerThread
private void handleInstall() {
...
if (params.isStaged) {
mStagedSession.verifySession();
} else {
verify();
}
}mStagedSession.verifySession最终也会走到verify，可以直接看verify方法
private void verify() {
try {
//1.创建安装apk需要的文件夹：
prepareInheritedFiles();
//2.解析APK文件并提取so库文件。其实就是解析AndroidManfest中的四大组件信息
parseApkAndExtractNativeLibraries();
//3.检验apk的过程
verifyNonStaged();
} catch (PackageManagerException e) {
final String completeMsg = ExceptionUtils.getCompleteMessage(e);
final String errorMsg = PackageManager.installStatusToString(e.error, completeMsg);
setSessionFailed(e.error, errorMsg);
onSessionVerificationFailure(e.error, errorMsg);
}
}重点来看3.检验apk的过程，verifyNonStaged在经过一系列session检查之后，最终会调用到PackageSessionVerifier的verifyAPK方法， verifyAPK内部设置了安装结果监听IPackageInstallObserver2：
//frameworks/base/services/core/java/com/android/server/pm/PackageSessionVerifier.java
private void verifyAPK(PackageInstallerSession session, Callback callback)
throws PackageManagerException {
final IPackageInstallObserver2 observer = new IPackageInstallObserver2.Stub() {
@Override
public void onUserActionRequired(Intent intent) {
throw new IllegalStateException();
}
@Override
public void onPackageInstalled(String basePackageName, int returnCode, String msg,
Bundle extras) {
if (session.isStaged() && returnCode == PackageManager.INSTALL_SUCCEEDED) {
// Continue verification for staged sessions
verifyStaged(session.mStagedSession, callback);
return;
}
if (returnCode != PackageManager.INSTALL_SUCCEEDED) {
String errorMessage = PackageManager.installStatusToString(returnCode, msg);
session.setSessionFailed(returnCode, errorMessage);
callback.onResult(returnCode, msg);
} else {
session.setSessionReady();
callback.onResult(PackageManager.INSTALL_SUCCEEDED, null);
}
}
};
final VerificationParams verifyingSession = makeVerificationParams(session, observer);
...
verifyingSession.verifyStage();
}
frameworks/base/services/core/java/com/android/server/pm/VerificationParams.java
public void verifyStage() {
mPm.mHandler.post(this::startCopy);
}可以看到verifyStage最终调用了mPm.mHandler post了一个startCopy的任务。
final void startCopy() {
handleStartCopy();
handleReturnCode();
}handleStartCopy和handleReturnCode是两个抽象方法：具体实现是在VerificationParams类中
public void handleStartCopy() {
//获取需要安装的apk包信息
PackageInfoLite pkgLite = PackageManagerServiceUtils.getMinimalPackageInfo(mPm.mContext,
mPackageLite, mOriginInfo.mResolvedPath, mInstallFlags, mPackageAbiOverride);
//校验需要更新的app的VersionCode，这里面会对VersionCode版本和原始版本进行校验。
Pair<Integer, String> ret = mInstallPackageHelper.verifyReplacingVersionCode(
pkgLite, mRequiredInstalledVersionCode, mInstallFlags);
if (!mOriginInfo.mExisting) {
//如果是PackageManager.INSTALL_APEX不是APEX包，也就是apk包，则调用sendApkVerificationRequest对APK包进行更新
if ((mInstallFlags & PackageManager.INSTALL_APEX) == 0) {
sendApkVerificationRequest(pkgLite);//关注点1
}
//回溯版本走的
if ((mInstallFlags & PackageManager.INSTALL_ENABLE_ROLLBACK) != 0) {
sendEnableRollbackRequest();
}
}
}//关注点1
private void sendApkVerificationRequest(PackageInfoLite pkgLite) {
...
//发送完整的校验请求
sendIntegrityVerificationRequest(verificationId, pkgLite, verificationState);
//发送package安装包校验
sendPackageVerificationRequest(
verificationId, pkgLite, verificationState);
...
}sendPackageVerificationRequest主要校验下面几个：
- 1.四大组件包信息校验
- 2.apk打包公钥校验
- 3.校验打包的sdk版本信息，通过添加广播的方式进行。
好了，继续回到startCopy的handleReturnCode方法
//frameworks/base/services/core/java/com/android/server/pm/VerificationParams.java
void handleReturnCode() {
sendVerificationCompleteNotification();
}
private void sendVerificationCompleteNotification() {
...
try {
mObserver.onPackageInstalled(null, mRet, mErrorMessage,
new Bundle());
} catch (RemoteException e) {
Slog.i(TAG, "Observer no longer exists.");
}
...
}在校验完毕成功以后，回调mObserver的onPackageInstalled方法。 而mObserver之前说过是在verifyAPK方法时传入的。
final IPackageInstallObserver2 observer = new IPackageInstallObserver2.Stub() {
@Override
public void onPackageInstalled(String basePackageName, int returnCode, String msg,
Bundle extras) {
...
if (returnCode != PackageManager.INSTALL_SUCCEEDED) {
String errorMessage = PackageManager.installStatusToString(returnCode, msg);
session.setSessionFailed(returnCode, errorMessage);
callback.onResult(returnCode, msg);
} else {
session.setSessionReady();
callback.onResult(PackageManager.INSTALL_SUCCEEDED, null);
}
}
};onPackageInstalled回调成功后会再次调用callback的onResult方法
callBack是在前面分析的PackageInstallerSession的verifyNonStaged方法中传入的，一层一层向外回调。
private void verifyNonStaged()
throws PackageManagerException {
mSessionProvider.getSessionVerifier().verify(this, (error, msg) -> {
mHandler.post(() -> {
if (dispatchPendingAbandonCallback()) {
// No need to continue if abandoned
return;
}
if (error == INSTALL_SUCCEEDED) {
onVerificationComplete();
} else {
onSessionVerificationFailure(error, msg);
}
});
});
}最终回调到onVerificationComplete方法，可以看到前面很大一部分是在对应用进行校验的部分。
下面分析的才是具体安装的过程：
@WorkerThread
private void onVerificationComplete() {
...
install();
}
private CompletableFuture<Void> install() {
List<CompletableFuture<InstallResult>> futures = installNonStaged();
...
}
private List<CompletableFuture<InstallResult>> installNonStaged() {
...
final InstallParams installingSession = makeInstallParams(future);
installingSession.installStage();
...
}
frameworks/base/services/core/java/com/android/server/pm/InstallParams.java
public void installStage() {
final Message msg = mPm.mHandler.obtainMessage(INIT_COPY);
msg.obj = this;
mPm.mHandler.sendMessage(msg);
}installStage发送了一个INIT_COPY的msg，定位到mPm = PackageManagerImpl.java mPm.mHandler = PackageHandler
final class PackageHandler extends Handler {
@Override
public void handleMessage(Message msg) {
try {
doHandleMessage(msg);
} finally {
Process.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT);
}
}
void doHandleMessage(Message msg) {
switch (msg.what) {
case INIT_COPY: {
HandlerParams params = (HandlerParams) msg.obj;
if (params != null) {
...
params.startCopy();
}
break;
}
}
}
}INIT_COPY的msg调用了HandlerParams的startCopy方法处理，而这个时候的HandlerParams的实现类是InstallParams.java,前面校验过程中的实现类是VerificationParams
final void startCopy() {
handleStartCopy();//关注点1
handleReturnCode();//关注点2
}先看关注点1
//frameworks/base/services/core/java/com/android/server/pm/InstallParams.java
public void handleStartCopy() {
PackageInfoLite pkgLite = PackageManagerServiceUtils.getMinimalPackageInfo(mPm.mContext,
mPackageLite, mOriginInfo.mResolvedPath, mInstallFlags, mPackageAbiOverride);
if (!mOriginInfo.mStaged && pkgLite.recommendedInstallLocation
== InstallLocationUtils.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
//先释放一部分不需要的缓存。
pkgLite.recommendedInstallLocation = mPm.freeCacheForInstallation(
pkgLite.recommendedInstallLocation, mPackageLite,
mOriginInfo.mResolvedPath, mPackageAbiOverride, mInstallFlags);
}
//根据默认的规则重写安装路径，主要是区分使用外置sdcard路径还是内置路径
mRet = overrideInstallLocation(pkgLite.packageName, pkgLite.recommendedInstallLocation,
pkgLite.installLocation);
}
再看关注点2：
void handleReturnCode() {
processPendingInstall();
}
private void processPendingInstall() {
//创建安装的参数信息
InstallArgs args = createInstallArgs(this);
if (mRet == PackageManager.INSTALL_SUCCEEDED) {
//关注点3 拷贝apk
mRet = args.copyApk();
}
if (mRet == PackageManager.INSTALL_SUCCEEDED) {
F2fsUtils.releaseCompressedBlocks(
mPm.mContext.getContentResolver(), new File(args.getCodePath()));
}
if (mParentInstallParams != null) {
mParentInstallParams.tryProcessInstallRequest(args, mRet);
} else {
PackageInstalledInfo res = new PackageInstalledInfo(mRet);
//关注点4
processInstallRequestsAsync(
res.mReturnCode == PackageManager.INSTALL_SUCCEEDED,
Collections.singletonList(new InstallRequest(args, res)));
}
}processPendingInstall关注两个部分：
- 1.拷贝apk
- 2.安装apk
1.拷贝apk：mRet = args.copyApk();
而args 是FileInstallArgs类对象
//frameworks/base/services/core/java/com/android/server/pm/FileInstallArgs.java
int copyApk() {
return doCopyApk();
}
private int doCopyApk() {
//1.给StageDir分配对应的临时文件夹以及权限
final File tempDir = mPm.mInstallerService.allocateStageDirLegacy(mVolumeUuid, isEphemeral);
mCodeFile = tempDir;
//2.拷贝Package，这里面主要是四大组件信息的拷贝
int ret = PackageManagerServiceUtils.copyPackage(
mOriginInfo.mFile.getAbsolutePath(), mCodeFile);
//3.根据abifilter 拷贝NativeLibrary ,so库到对应的lib目录下
handle = NativeLibraryHelper.Handle.create(mCodeFile);
ret = NativeLibraryHelper.copyNativeBinariesWithOverride(handle, libraryRoot,
mAbiOverride, isIncremental);
return ret;
}先来分析1处allocateStageDirLegacy
public File allocateStageDirLegacy(String volumeUuid, boolean isEphemeral) throws IOException {
synchronized (mSessions) {
try {
final int sessionId = allocateSessionIdLocked();
mLegacySessions.put(sessionId, true);
final File sessionStageDir = buildTmpSessionDir(sessionId, volumeUuid);
prepareStageDir(sessionStageDir);
return sessionStageDir;
} catch (IllegalStateException e) {
throw new IOException(e);
}
}
}看buildTmpSessionDir，这个前面也分析过，最后返回的File路径为：data/app/vmdl{$sessionId}.tmp
再来分析2处PackageManagerServiceUtils.copyPackage
public static int copyPackage(String packagePath, File targetDir) {
try {
final File packageFile = new File(packagePath);
//解析APK文件到ParseResult中
final ParseResult<PackageLite> result = ApkLiteParseUtils.parsePackageLite(
input.reset(), packageFile, /* flags */ 0);
//获取apk的文件PackageLite信息
final PackageLite pkg = result.getResult();
//拷贝file，核心方法
copyFile(pkg.getBaseApkPath(), targetDir, "base.apk");
return PackageManager.INSTALL_SUCCEEDED;
} catch (IOException | ErrnoException e) {
}
}
private static void copyFile(String sourcePath, File targetDir, String targetName)
throws ErrnoException, IOException {
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);
}
}copyPackage会先去解析apk文件，然后调用copyFile方法，copyFile中调用Os.open去打开targetFile目标文件， 调用FileUtils.copy方法将原文件拷贝到目标文件中
2.安装apk：processInstallRequestsAsync
// Queue up an async operation since the package installation may take a little while.
private void processInstallRequestsAsync(boolean success,
List<InstallRequest> installRequests) {
mPm.mHandler.post(() -> {
mInstallPackageHelper.processInstallRequests(success, installRequests);
});
}
frameworks/base/services/core/java/com/android/server/pm/InstallPackageHelper.java
public void processInstallRequests(boolean success, List<InstallRequest> installRequests) {
List<InstallRequest> apkInstallRequests = new ArrayList<>();
for (InstallRequest request : installRequests) {
...
apkInstallRequests.add(request);
}
if (success) {
for (InstallRequest request : apkInstallRequests) {
//预安装，内部主要是做clean操作
request.mArgs.doPreInstall(request.mInstallResult.mReturnCode);
}
synchronized (mPm.mInstallLock) {
//实际安装apk过程
installPackagesTracedLI(apkInstallRequests);
}
}
...
}
private void installPackagesTracedLI(List<InstallRequest> requests) {
...
installPackagesLI(requests);
...
}下面我们重点来分析下installPackagesLI
private void installPackagesLI(List<InstallRequest> requests) {
for (InstallRequest request : requests) {
//阶段1：prepare阶段
repareResult = preparePackageLI(request.mArgs, request.mInstallResult);
//阶段2：scan阶段
final ScanResult result = scanPackageTracedLI(
prepareResult.mPackageToScan, prepareResult.mParseFlags,
prepareResult.mScanFlags, System.currentTimeMillis(),
request.mArgs.mUser, request.mArgs.mAbiOverride);
}
//阶段3：Reconcile阶段
reconciledPackages = ReconcilePackageUtils.reconcilePackages(
reconcileRequest, mSharedLibraries,
mPm.mSettings.getKeySetManagerService(), mPm.mSettings);
}
commitRequest = new CommitRequest(reconciledPackages,
mPm.mUserManager.getUserIds());
//阶段4：Commit阶段
commitPackagesLocked(commitRequest);
//阶段5：完成apk安装
executePostCommitSteps(commitRequest);
}installPackagesLI是最终安装应用的方法：主要分为4个阶段
- 阶段1：prepare阶段:分析当前安装包的状态，解析安装包并对其做初始化验证
- 阶段2：scan阶段：根据prepare阶段中收集的安装包状态信息去扫描解析出来的包
- 阶段3：Reconcile阶段:验证scan阶段扫描到的Package信息以及当前系统状态，确保apk的正确安装。
- 阶段4：Commit阶段：提交所有扫描的包并更新系统状态。这是唯一可以在安装流程和所有可预测错误中修改系统状态的地方.
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。
最后通过executePostCommitSteps完成apk的安装，执行dex优化等操作
阶段5：完成apk安装
- private void executePostCommitSteps(CommitRequest commitRequest) { for (ReconciledPackage reconciledPkg : commitRequest.mReconciledPackages.values()) { // prepareAppDataPostCommitLIF经过一系列调用会走到Installer的createAppData方法。 mAppDataHelper.prepareAppDataPostCommitLIF(pkg, 0); /* 检测是否需要进行dex优化：同时满足下面三种情况就需要 1.不是一个即时应用app或者如果是的话通过gservices进行dex优化操作 2.debuggable为false 3.不在增量文件系统上。 */ final boolean performDexopt = (!instantApp || android.provider.Settings.Global.getInt( mContext.getContentResolver(), android.provider.Settings.Global.INSTANT_APP_DEXOPT_ENABLED, 0) != 0) && !pkg.isDebuggable() && (!onIncremental) && dexoptOptions.isCompilationEnabled(); if (performDexopt) { //获取so库所在的目录 PackageSetting realPkgSetting = result.mExistingSettingCopied ? result.mRequest.mPkgSetting : result.mPkgSetting; boolean isUpdatedSystemApp = reconciledPkg.mPkgSetting.getPkgState() .isUpdatedSystemApp(); //更新系统app信息。 realPkgSetting.getPkgState().setUpdatedSystemApp(isUpdatedSystemApp); //进行dex优化 mPackageDexOptimizer.performDexOpt(pkg, realPkgSetting, null /* instructionSets */, mPm.getOrCreateCompilerPackageStats(pkg), mDexManager.getPackageUseInfoOrDefault(packageName), dexoptOptions); } //通知BackgroundDexOptService服务当前packageName的应用进行了更新。 BackgroundDexOptService.getService().notifyPackageChanged(packageName); notifyPackageChangeObserversOnUpdate(reconciledPkg); } }
阶段5：主要做了下面两件事
任务1：调用prepareAppDataPostCommitLIF方法,最终执行到createAppData方法进行app的安装.
public @NonNull CreateAppDataResult createAppData(@NonNull CreateAppDataArgs args) throws InstallerException { ... try { return mInstalld.createAppData(args); } catch (Exception e) { throw InstallerException.from(e); } }
mInstalld在前面分析过了，installd进程 的执行权限为 root，所有实际的应用安装，卸载等操作都是通过这个服务进行的。 PKMS只是java层的封装。mInstalld进程和PKMS是通过binder进行通讯的。
任务2.调用performDexOpt进行dex优化 同时满足下面三种情况就需要
- 1.不是一个即时应用app或者如果是的话通过gservices进行dex优化操作
- 2.debuggable为false
- 3.不在增量文件系统上。
然后关于dex优化部分，后面会单独出一篇文章来讲解。
关于应用安装部分就讲到这里了。
总结
关于Android中包管理机制，由于源码部分内容较多，小余使用了两篇文章来讲解。希望你能从中有所收获。
如果文字对你帮助，帮忙给小余点个赞，谢啦。
参考：
一篇文章看明白 Android PackageManagerService 工作流程
深入理解安卓-了解一下 Android 10 中的 APEX
Android 系统服务 PMS Installd 守护进程(二)
ANDROID 包管理（PACKAGEMANAGERSERVICE）
android系统源码目录system/framework下各个jar包的用途
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