本文基于Android 10源码分析
前言
??PackageManagerService(简称PKMS),是Android系统中核心服务之一,管理着所有与package相关的工作,常见的比如安装、卸载应用, 信息查询等工作,主要完成以下核心功能:
解析AndroidManifest.xml清单文件,解析清单文件中的所有节点信息;
扫描本地文件,主要针对apk,主要是系统应用、本地安装应用等;
管理本地apk,主要包括安装、删除等等;
管理设备上安装的所有应用程序,并在系统启动时加载应用程序;
根据请求的Intent匹配到对应的Activity、Provider、Service,提供包含包名和Component的信息对象;
调用需要权限的系统函数时,检查程序是否具备相应权限从而保证系统安全;
提供应用程序的安装、卸载的接口。
??本篇文章重点介绍一下apk安装流程。
1.安装apk的方式
??Android应用安装有如下四种方式:
系统应用和预制应用安装――开机时完成,没有安装界面,在PKMS的构造函数中完成安装;
网络下载应用安装――通过应用商店应用完成,调用PackageManager.installPackages(),有安装界面;
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PKMS.installStage()完成安装;
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。
??上述几种方式均通过PackageInstallObserver来监听安装是否成功。
2.apk文件结构
??生成的APK文件本质还是一个zip文件,只不过被Google强行修改了一下后缀名称而已。所以我们将APK的后缀修改成.zip就可以查看其包含的内容了。
(1)主要由7部分组成 (下图来源于其他作者博客: Android apk结构分析)
(2)META-INF目录下3个重要文件
(3)res目录下的文件说明
(4)细节说明
META-INF:关于签名的信息存放,应用安装验证签名的时候会验证该文件里面的信息,里面的资源文件,是被编译过的。raw和图片是保持原样的,但是其他的文件会被编译成二进制文件;
res: 这里面的资源是不经过编译原样打包进来的;
AndroidManifest.xml:程序全局配置文件,该文件是每个应用程序都必须定义和包含的文件,它描述了应用程序的名字、版本、权限、引用的库文件等等信息;
classes.dex:Dalvik字节码文件,Android会将所有的class文件全部放到这一个文件里;
resources.arsc:编译后的二进制资源文件,保存资源文件的索引,由aapt生成;
lib: 如果存在的话,存放的是ndk编出来的so库。
3.apk安装过程
??这里我们主要来讲解下载APK后,点击进行安装的过程,整体上来说大致分为4个步骤:
将APK的信息通过IO流的形式写入到PackageInstaller.Session中;
调用PackageInstaller.Session的commit方法,将APK的信息交由PKMS处理;
拷贝APK;
安装apk。
??整个过程涉及到3个跨进程通信的Binder:
APK从应用市场下载后点击安装,则会跳转到(com.android.packageinstaller) PackageInstaller.apk 的安装界面上,供用户选择安装或取消,之前也分析过前半段的流程,是怎么跳转到PackageInstaller.apk 的安装界面中, 请查阅:Android PackageManagerService--01:应用市场下载安装apk流程
3.1 点击安装到APK拷贝
(1)时序图
(2)点击一个未安装的apk后,会弹出安装界面,点击确定按钮后,会进入PackageInstallerActivity.java的bindUi()中的mAlert点击事件(Activity中的onCreate中调用bindUi);
??点击apk后,弹出的安装界面底部显示的是一个Dialog,主要由bindUi构成,上面有取消和安装两个按钮,点击安装之后调用startInstall()进行安装。bindUi方法的代码如下:
// frameworks/base/packages/apps/PackageInstaller/src/com/android/packageinstaller/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的安装, 关键代码
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setPermissionResult()完成取消安装
mInstaller.setPermissionsResult(mSessionId, false);
}
finish();
}, null);
setupAlert();
mOk = mAlert.getButton(DialogInterface.BUTTON_POSITIVE);
mOk.setEnabled(false);
if (!mOk.isInTouchMode()) {
mAlert.getButton(DialogInterface.BUTTON_NEGATIVE).requestFocus();
}
}
(3)接下来看看startInstall()方法,封装了一个Intent跳转到InstallInstalling.java文件中
// frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/PackageInstallerActivity.java
private void startInstall() {
Intent newIntent = new Intent();
...
newIntent.setClass(this, InstallInstalling.class);
...
startActivity(newIntent);
}
(4)InstallInstalling的Activity启动后,进入onCreate方法
// frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/InstallInstalling.java
protected void onCreate(@Nullable Bundle savedInstanceState) {
....
if ("package".equals(mPackageURI.getScheme())) {
try {
getPackageManager().installExistingPackage(appInfo.packageName);
launchSuccess();
} catch (PackageManager.NameNotFoundException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
} else {
//根据mPackageURI创建一个对应的File
final File sourceFile = new File(mPackageURI.getPath());
// 1.如果savedInstanceState不为null,获取此前保存的mSessionId和mInstallId,
// 其中mSessionId是安装包的会话Id,mInstallId是等待安装的事件Id
if (savedInstanceState != null) {
mSessionId = savedInstanceState.getInt(SESSION_ID);
mInstallId = savedInstanceState.getInt(INSTALL_ID);
// Reregister for result; might instantly call back if result was delivered while
// activity was destroyed
try {
// 2\. 根据mInstallId向InstallEventReceiver注册一个观察者,
// launchFinishBasedOnResult会接收到安装事件的回调,无论安装成功还是失败
// 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); // 监听安装结果
} catch (EventResultPersister.OutOfIdsException e) {
// Does not happen
}
} else {
//3\. 创建SessionParams,它用来代表安装会话的参数,组装params
PackageInstaller.SessionParams params = new PackageInstaller.SessionParams(
PackageInstaller.SessionParams.MODE_FULL_INSTALL);
params.setInstallAsInstantApp(false);
params.setReferrerUri(getIntent().getParcelableExtra(Intent.EXTRA_REFERRER));
params.setOriginatingUri(getIntent()
.getParcelableExtra(Intent.EXTRA_ORIGINATING_URI));
params.setOriginatingUid(getIntent().getIntExtra(Intent.EXTRA_ORIGINATING_UID,
UID_UNKNOWN));
params.setInstallerPackageName(getIntent().getStringExtra(
Intent.EXTRA_INSTALLER_PACKAGE_NAME));
params.setInstallReason(PackageManager.INSTALL_REASON_USER);
// 4.根据mPackageUri对包进行轻量级的解析,并将解析的参数赋值给SessionParams
File file = new File(mPackageURI.getPath());
try {
PackageParser.PackageLite pkg = PackageParser.parsePackageLite(file, 0);
params.setAppPackageName(pkg.packageName);
//设置apk的安装路径
params.setInstallLocation(pkg.installLocation);
//设置apk的大小
params.setSize(
PackageHelper.calculateInstalledSize(pkg, false, params.abiOverride));
....
//5\. 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
try {
mInstallId = InstallEventReceiver
.addObserver(this, EventResultPersister.GENERATE_NEW_ID,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
....
try {
// 6\. 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方法阿里创建并返回mSessionId
mSessionId = getPackageManager().getPackageInstaller().createSession(params);
} catch (IOException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
.....
}
再来总结一下上面onCreate方法中所做的工作:
如果savedInstanceState不为null,获取此前保存的mSessionId和mInstallId,其中mSessionId是安装包的会话Id,mInstallId是等待的安装事件Id;
根据mInstallId向InstallEventReceiver注册一个观察者,launchFinishBasedOnResult会接收到安装事件的回调,无论安装成功或者是安装失败都会关闭当前的Activity(InstallInstalling)。如果saveInstanceState为null,代码的逻辑也是类似的。
创建SessionParams,它用来代表安装会话的参数,组装Params;
根据mPackageUri对包(APK)进行轻量级的解析,并将解析的参数赋值SessionParams;
向InstallEventReceiver注册一个观察者返回一个新的mInstallId;
PackageInstaller的createSession方法内部会通过IPackageInstallerService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。
(5)接下来继续分析 InstallInstalling.java的onResume()方法
// frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/InstallInstalling.java
@Override
protected void onResume() {
super.onResume();
...
if (sessionInfo != null && !sessionInfo.isActive()) {
// 创建内部类InstallingAsyncTask的对象,调用execute(),最终进入onPostExecute()方法
mInstallingTask = new InstallingAsyncTask();
mInstallingTask.execute();
} else {
// we will receive a broadcast when the install is finished
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
}
...
}
(6)InstallingAsyncTask的doInBackground()会根据包(APK)的Uri,将APK的信息通过IO流的形式写入到PackageInstaller.Session中, 最后在onPostExecute()中调用PackageInstaller.Session的commit方法,进行安装。
// frameworks/base/packages/PackageInstaller/src/com/android/packageinstaller/InstallInstalling.java
private final class InstallingAsyncTask extends AsyncTask<Void, Void,
PackageInstaller.Session> {
volatile boolean isDone;
@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();
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;
}
// 将APK的信息通过IO流的形式写入到PackageInstaller.Session中
out.write(buffer, 0, numRead);
...
}
@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);
// 调用PackageInstaller.Session的commit方法,进行安装
session.commit(pendingIntent.getIntentSender());
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
} else {
getPackageManager().getPackageInstaller().abandonSession(mSessionId);
if (!isCancelled()) {
launchFailure(PackageManager.INSTALL_FAILED_INVALID_APK, null);
}
}
}
}
(7)接着看一下PackageInstaller.Session的commit方法, 通过IPackageInstallerSession.aidl 跨进程通信,调用 PackageInstallerSession.java 中的commit方法
// frameworks/base/services/core/java/com/android/server/pm/PackageInstallerSession.java
public void commit(@NonNull IntentSender statusReceiver, boolean forTransfer) {
...
//调用markAsCommitted()
if (!markAsCommitted(statusReceiver, forTransfer)) {
return;
}
mHandler.obtainMessage(MSG_COMMIT).sendToTarget();
...
}
markAsCommitted方法中会将包的信息封装为PackageInstallObserverAdapter ,它在PKMS中被定义,然后返回到commit()中,向Handler发送一个类型为MSG_COMMIT的消息 。
(8)接着看消息处理的方法
// frameworks/base/services/core/java/com/android/server/pm/PackageInstallerSession.java
private final Handler.Callback mHandlerCallback = new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case MSG_COMMIT:
handleCommit();// 处理消息
break;
....
}
-----------------------
private void handleCommit() {
.....
synchronized (mLock) {
commitNonStagedLocked(childSessions);
}
....
}
(9)commitNonStagedLocked()中首先调用了PackageInstallObserver的onPackageInstalled方法,将Complete方法出现的PackageManagerException的异常信息回调给PackageInstallObserverAdapter。
// frameworks/base/services/core/java/com/android/server/pm/PackageInstallerSession.java
@GuardedBy("mLock")
private void commitNonStagedLocked(List<PackageInstallerSession> childSessions)
throws PackageManagerException {
....
if (!success) {
try {
mRemoteObserver.onPackageInstalled(
null, failure.error, failure.getLocalizedMessage(), null);
} catch (RemoteException ignored) {
}
return;
}
// 最终调用这个方法
mPm.installStage(activeChildSessions);
....
}
(10)最终调用installStage(),进入PKMS中
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
void installStage(List<ActiveInstallSession> children)
throws PackageManagerException {
final Message msg = mHandler.obtainMessage(INIT_COPY);
.....
mHandler.sendMessage(msg);
.....
}
-------------------------------------------
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;
}
......
(11)在Handler中对INIT_COPY消息的处理中,调用了HandlerParams.startCopy方法
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
final void startCopy() {
if (DEBUG_INSTALL) Slog.i(TAG, "startCopy " + mUser + ": " + this);
handleStartCopy();
handleReturnCode();
}
(12)handleStartCopy()需要执行下面几步:
首先检查文件和cid是否已经生成,如果生成则设置installFlags;
检查空间大小,如果空间不够就会释放无用的空间;
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安装器,如果有,则延迟检测。主要分三步:
1)首先新建一个验证Intent,然后设置相关的信息;
2)之后获取验证器列表;
3)最后向每个验证器发送验证Intent。
// Android 11.0
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
public void handleStartCopy() {
int ret = PackageManager.INSTALL_SUCCEEDED;
// 1.首先检查文件和cid是否已经生成,如生成则设置installFlags
if (origin.staged) {
if (origin.file != null) {
installFlags |= PackageManager.INSTALL_INTERNAL;
} else {
throw new IllegalStateException("Invalid stage location");
}
}
.....
// 2\. 检查空间大小,如果空间不够则释放无用空间
if (!origin.staged && pkgLite.recommendedInstallLocation
== PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
// TODO: focus freeing disk space on the target device
final StorageManager storage = StorageManager.from(mContext);
final long lowThreshold = storage.getStorageLowBytes(
Environment.getDataDirectory());
final long sizeBytes = PackageManagerServiceUtils.calculateInstalledSize(
origin.resolvedPath, packageAbiOverride);
if (sizeBytes >= 0) {
try {
mInstaller.freeCache(null, sizeBytes + lowThreshold, 0, 0);
pkgLite = PackageManagerServiceUtils.getMinimalPackageInfo(mContext,
origin.resolvedPath, installFlags, packageAbiOverride);
} catch (InstallerException e) {
Slog.w(TAG, "Failed to free cache", e);
}
}
if (pkgLite.recommendedInstallLocation
== PackageHelper.RECOMMEND_FAILED_INVALID_URI) {
pkgLite.recommendedInstallLocation
= PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE;
}
}
if (ret == PackageManager.INSTALL_SUCCEEDED) {
.....
{
// 3\. 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
loc = installLocationPolicy(pkgLite);
if (loc == PackageHelper.RECOMMEND_FAILED_VERSION_DOWNGRADE) {
ret = PackageManager.INSTALL_FAILED_VERSION_DOWNGRADE;
} else if (loc == PackageHelper.RECOMMEND_FAILED_WRONG_INSTALLED_VERSION) {
ret = PackageManager.INSTALL_FAILED_WRONG_INSTALLED_VERSION;
} else if (!onInt) {
// Override install location with flags
if (loc == PackageHelper.RECOMMEND_INSTALL_EXTERNAL) {
// Set the flag to install on external media.
installFlags &= ~PackageManager.INSTALL_INTERNAL;
} else if (loc == PackageHelper.RECOMMEND_INSTALL_EPHEMERAL) {
if (DEBUG_INSTANT) {
Slog.v(TAG, "...setting INSTALL_EPHEMERAL install flag");
}
installFlags |= PackageManager.INSTALL_INSTANT_APP;
installFlags &= ~PackageManager.INSTALL_INTERNAL;
} else {
// Make sure the flag for installing on external
// media is unset
installFlags |= PackageManager.INSTALL_INTERNAL;
}
}
}
}
final InstallArgs args = createInstallArgs(this);
mVerificationCompleted = true;
mIntegrityVerificationCompleted = true;
mEnableRollbackCompleted = true;
mArgs = args;
if (ret == PackageManager.INSTALL_SUCCEEDED) {
final int verificationId = mPendingVerificationToken++;
// Perform package verification (unless we are simply moving the package).
if (!origin.existing) {
PackageVerificationState verificationState =
new PackageVerificationState(this);
mPendingVerification.append(verificationId, verificationState);
// 发送一个请求来检查包的完整性
sendIntegrityVerificationRequest(verificationId, pkgLite, verificationState);
// 向验证者发送验证包的请求
ret = sendPackageVerificationRequest(
verificationId, pkgLite, verificationState);
}
...
mRet = ret;
}
(13)在Android 11.0 中是通过sendPackageVerificationRequest来验证包的
// Android 11.0
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
int sendPackageVerificationRequest(
int verificationId,
PackageInfoLite pkgLite,
PackageVerificationState verificationState) {
int ret = INSTALL_SUCCEEDED;
.....
if (!origin.existing
&& isVerificationEnabled
&& (!isIncrementalInstall || !isV4Signed)) {
// 4\. 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
// 4.1 构造验证Intent
final Intent verification = new Intent(
Intent.ACTION_PACKAGE_NEEDS_VERIFICATION);
verification.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
verification.setDataAndType(Uri.fromFile(new File(origin.resolvedPath)),
PACKAGE_MIME_TYPE);
verification.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
....
populateInstallerExtras(verification);
// 4.2 获取验证器列表
final List<ComponentName> sufficientVerifiers = matchVerifiers(pkgLite,
receivers, verificationState);
DeviceIdleInternal idleController =
mInjector.getLocalDeviceIdleController();
final long idleDuration = getVerificationTimeout();
final BroadcastOptions options = BroadcastOptions.makeBasic();
options.setTemporaryAppWhitelistDuration(idleDuration);
/*
* If any sufficient verifiers were listed in the package
* manifest, attempt to ask them.
*/
if (sufficientVerifiers != null) {
final int n = sufficientVerifiers.size();
if (n == 0) {
Slog.i(TAG, "Additional verifiers required, but none installed.");
ret = PackageManager.INSTALL_FAILED_VERIFICATION_FAILURE;
} else {
for (int i = 0; i < n; i++) {
final ComponentName verifierComponent = sufficientVerifiers.get(i);
idleController.addPowerSaveTempWhitelistApp(Process.myUid(),
verifierComponent.getPackageName(), idleDuration,
verifierUser.getIdentifier(), false, "package verifier");
// 4.3 向每个验证器发送验证Intent
// 向验证器客户端发送Intent,只有当验证成功之后才开启copy工作
// 如果没有任何验证器则直接拷贝
final Intent sufficientIntent = new Intent(verification);
sufficientIntent.setComponent(verifierComponent);
mContext.sendBroadcastAsUser(sufficientIntent, verifierUser,
/* receiverPermission= */ null,
options.toBundle());
}
}
}
.....
return ret;
}
(14)向验证器客户端发送Intent,只有当验证成功之后才会开启copy工作。如果没有任何验证器则直接拷贝。在handleReturnCode中调用copyApk()进行APK的拷贝工作。
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
void handleReturnCode() {
if (mVerificationCompleted
&& mIntegrityVerificationCompleted && mEnableRollbackCompleted) {
if ((installFlags & PackageManager.INSTALL_DRY_RUN) != 0) {
String packageName = "";
ParseResult<PackageLite> result = ApkLiteParseUtils.parsePackageLite(
new ParseTypeImpl(
(changeId, packageName1, targetSdkVersion) -> {
ApplicationInfo appInfo = new ApplicationInfo();
appInfo.packageName = packageName1;
appInfo.targetSdkVersion = targetSdkVersion;
return mPackageParserCallback.isChangeEnabled(changeId,
appInfo);
}).reset(),
origin.file, 0);
if (result.isError()) {
Slog.e(TAG, "Can't parse package at " + origin.file.getAbsolutePath(),
result.getException());
} else {
packageName = result.getResult().packageName;
}
try {
observer.onPackageInstalled(packageName, mRet, "Dry run", new Bundle());
} catch (RemoteException e) {
Slog.i(TAG, "Observer no longer exists.");
}
return;
}
if (mRet == PackageManager.INSTALL_SUCCEEDED) {
// 调用copyApk方法
mRet = mArgs.copyApk();
}
processPendingInstall(mArgs, mRet); // 这里是安装apk的流程,放到3.2节中分析
}
}
(15)调用了InstallArgs.copyApk方法,最终会调用到FileInstallArgs.copyApk方法
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
int copyApk() {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "copyApk");
try {
// 调用doCopyApk方法
return doCopyApk();
} finally {
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
}
------------------------------------------
private int doCopyApk() {
.....
// 调用PackageManagerServiceUtils.copyPackage方法
int ret = PackageManagerServiceUtils.copyPackage(
origin.file.getAbsolutePath(), codeFile);
if (ret != PackageManager.INSTALL_SUCCEEDED) {
Slog.e(TAG, "Failed to copy package");
return ret;
}
.....
return ret;
}
(16)在doCopyApk方法中调用了PackageManagerServiceUtils.copyPackage方法,其代码如下:
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerServiceUtils.java\
public static int copyPackage(String packagePath, File targetDir) {
if (packagePath == null) {
return PackageManager.INSTALL_FAILED_INVALID_URI;
}
try {
final File packageFile = new File(packagePath);
final PackageParser.PackageLite pkg = PackageParser.parsePackageLite(packageFile, 0);
copyFile(pkg.baseCodePath, targetDir, "base.apk");
if (!ArrayUtils.isEmpty(pkg.splitNames)) {
for (int i = 0; i < pkg.splitNames.length; i++) {
// 调用了copyFile方法
copyFile(pkg.splitCodePaths[i], targetDir,
"split_" + pkg.splitNames[i] + ".apk");
}
}
return PackageManager.INSTALL_SUCCEEDED;
} catch (PackageParserException | IOException | ErrnoException e) {
Slog.w(TAG, "Failed to copy package at " + packagePath + ": " + e);
return PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
}
}
(17)在copyFile方法中,通过文件流的操作,把APK拷贝到/data/app等目录
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerServiceUtils.java\
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);
}
}
3.2 安装apk流程
??APK拷贝完成后,进入真正的安装,时序图如下:
(1)在上述handleReturnCode方法中,执行了copyApk方法后,最后又执行了processPendingInstall方法。
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void processPendingInstall(final InstallArgs args, final int currentStatus) {
if (args.mMultiPackageInstallParams != null) {
args.mMultiPackageInstallParams.tryProcessInstallRequest(args, currentStatus);
} else {
// 1\. 设置安装参数
PackageInstalledInfo res = createPackageInstalledInfo(currentStatus);
// 2\. 创建一个新线程,处理安装参数,进行安装
processInstallRequestsAsync(
res.returnCode == PackageManager.INSTALL_SUCCEEDED,
Collections.singletonList(new InstallRequest(args, res)));
}
}
--------------------------------------------------
private void processInstallRequestsAsync(boolean success,
List<InstallRequest> installRequests) {
mHandler.post(() -> {
if (success) {
for (InstallRequest request : installRequests) {
// 1\. 如果之前安装失败,清除无用信息
request.args.doPreInstall(request.installResult.returnCode);
}
synchronized (mInstallLock) {
// 2\. installPackagesTracedLI是安装过程的核心方法
// 然后调用installPackagesLI进行安装
installPackagesTracedLI(installRequests);
}
for (InstallRequest request : installRequests) {
// 3\. 如果之前安装失败,清除无用信息
request.args.doPostInstall(
request.installResult.returnCode, request.installResult.uid);
}
}
for (InstallRequest request : installRequests) {
restoreAndPostInstall(request.args.user.getIdentifier(), request.installResult,
new PostInstallData(request.args, request.installResult, null));
}
});
}
--------------------------------------------------
int doPreInstall(int status) {
if (status != PackageManager.INSTALL_SUCCEEDED) {
// 清除无用信息
cleanUp();
}
return status;
}
--------------------------------------------------
int doPostInstall(int status, int uid) {
if (status != PackageManager.INSTALL_SUCCEEDED) {
// 调用cleanUp清除无用信息
cleanUp();
}
return status;
}
(2)在installPackagesLI方法中,以原子的方式安装一个或多个包。此操作分为四个阶段:
1)Prepare准备:分析任何当前安装状态,分析包并对其进行初始验证;
2)Scan 扫描:扫描分析准备阶段拿到的包;
3) Reconcile协调:包的扫描结果,用于协调可能向系统中添加的一个或多个包;
4) Commit提交:提交所有扫描的包并更新系统状态,这是安装流程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的可预测的错误;
5)完成APK的安装。
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void installPackagesLI(List<InstallRequest> requests) {
......
// 1\. Prepare 准备:分析任何当前安装状态,分析包并对其进行初始验证
prepareResult = preparePackageLI(request.args, request.installResult);
......
// 2\. Scan 扫描:扫描分析准备阶段拿到的包
final ScanResult result = scanPackageTracedLI(
prepareResult.packageToScan, prepareResult.parseFlags,
prepareResult.scanFlags, System.currentTimeMillis(),
request.args.user, request.args.abiOverride);
......
// 3\. Reconcile协调:包的扫描结果,用于协调可能向系统中添加的一个或多个包
ReconcileRequest reconcileRequest = new ReconcileRequest(preparedScans, installArgs,
installResults,
prepareResults,
mSharedLibraries,
Collections.unmodifiableMap(mPackages), versionInfos,
lastStaticSharedLibSettings);
......
// 4\. Commit 提交:提交所有扫描的包并更新系统状态。这是安装流程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的可预测的错误
commitPackagesLocked(commitRequest);
......
// 5\. 完成APK的安装
executePostCommitSteps(commitRequest);
}
(3)executePostCommitSteps安装APK,并为新的代码路径准备应用程序配置文件,并在此检查是否需要dex优化。
??如果是直接安装新包,会为新的代码路径准备应用程序配置文件;如果是替换安装,其主要过程为更新设置,清除原有的某些APP数据,重新生成相关的app数据目录等步骤,同时要区分系统应用替换和非系统应用替换。而安装新包,则直接更新设置,生成APP数据即可。
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void executePostCommitSteps(CommitRequest commitRequest) {
for (ReconciledPackage reconciledPkg : commitRequest.reconciledPackages.values()) {
......
// 1) 进行安装
prepareAppDataAfterInstallLIF(pkg);
// 2) 如果需要替换安装,则需要清除原有的App数据
if (reconciledPkg.prepareResult.clearCodeCache) {
clearAppDataLIF(pkg, UserHandle.USER_ALL, FLAG_STORAGE_DE | FLAG_STORAGE_CE
| FLAG_STORAGE_EXTERNAL | Installer.FLAG_CLEAR_CODE_CACHE_ONLY);
}
...
// 3) 为新的代码路径准备应用程序配置文件。这需要在调用dexopt之前完成,
// 以便任何安装时配置文件都可以用于优化
mArtManagerService.prepareAppProfiles(
pkg,
resolveUserIds(reconciledPkg.installArgs.user.getIdentifier()),
/* updateReferenceProfileContent= */ true);
// 4) 检查是否需要优化dex文件
final boolean performDexopt =
(!instantApp || Global.getInt(mContext.getContentResolver(),
Global.INSTANT_APP_DEXOPT_ENABLED, 0) != 0)
&& !pkg.isDebuggable()
&& (!onIncremental);
if (performDexopt) {
// 5) 执行dex优化
mPackageDexOptimizer.performDexOpt(pkg, realPkgSetting,
null /* instructionSets */,
getOrCreateCompilerPackageStats(pkg),
mDexManager.getPackageUseInfoOrDefault(packageName),
dexoptOptions);
}
BackgroundDexOptService.notifyPackageChanged(packageName);
notifyPackageChangeObserversOnUpdate(reconciledPkg);
}
}
(4)PackageManagerService.prepareAppDataAfterInstallLIF()通过一系列的调用,最终会调用到Installer.java的createAppData()方法进行安装,交给installed进程进行APK的安装。调用过程如下:
prepareAppDataAfterInstallLIF()
|
prepareAppDataLIF()
|
prepareAppDataLeafLIF()
|
[Installer.java]createAppData()
// frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java
private void prepareAppDataAfterInstallLIF(AndroidPackage pkg) {
......
for (UserInfo user : mUserManager.getUsers(false /*excludeDying*/)) {
......
if (ps.getInstalled(user.id)) {
// TODO: when user data is locked, mark that we're still dirty
prepareAppDataLIF(pkg, user.id, flags);
}
}
}
-----------------------------------------------------
private void prepareAppDataLIF(AndroidPackage pkg, int userId, int flags) {
if (pkg == null) {
Slog.wtf(TAG, "Package was null!", new Throwable());
return;
}
// 调用prepareAppDataLeafLIF方法
prepareAppDataLeafLIF(pkg, userId, flags);
}
-----------------------------------------------------
private void prepareAppDataLeafLIF(AndroidPackage pkg, int userId, int flags) {
......
try {
// 调用Install守护进程的入口
ceDataInode = mInstaller.createAppData(volumeUuid, packageName, userId, flags,
appId, seInfo, pkg.getTargetSdkVersion());
} catch (InstallerException e) {
if (pkg.isSystem()) {
destroyAppDataLeafLIF(pkg, userId, flags);
try {
ceDataInode = mInstaller.createAppData(volumeUuid, packageName, userId,
flags,appId, seInfo, pkg.getTargetSdkVersion());
} catch (InstallerException e2) {
......
}
}
}
}
(5)跳转到Installer.java
// frameworks/base/services/core/java/com/android/server/pm/Installer.java
public long createAppData(String uuid, String packageName, int userId, int flags, int
appId,String seInfo, int targetSdkVersion) throws InstallerException {
if (!checkBeforeRemote()) return -1;
try {
// mInstalld为IInstall的对象,即通过Binder调用到进程installd,
// 最终调用installd的createAppData()
return mInstalld.createAppData(uuid, packageName, userId, flags, appId, seInfo,
targetSdkVersion);
} catch (Exception e) {
throw InstallerException.from(e);
}
}
至于之后的IInstall服务安装过程这里不再分析,可参考:Android安装服务installd源码分析和Android 源码 installd 启动流程分析。
4.总结
??APK的安装主要分为以下四步:
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。
??最终是交给IInstalld守护进程进行真正的安装操作。