当我们安装应用程序的时候，会弹出安装界面，那么，在我们点击安装之后，发生了什么呢？今天就来了解下，应用程序是如何安装的。首先，我们今天介绍的是通过安装器安装应用，当然，在pms的构造函数中，也会将我们原先安装好的应用装载到内存中。
以6.0源码为例。安装器在源码目录packages/apps/PackageInstaller中，
2.安装器
显示安装 取消按钮的那个界面对应着PackageInstallerActivity，而安装按钮对应的是mOk，对应部分代码。
if (v == mOk) {
if (mOkCanInstall || mScrollView == null) {
mInstallFlowAnalytics.setInstallButtonClicked();
if (mSessionId != -1) {
mInstaller.setPermissionsResult(mSessionId, true);
// We're only confirming permissions, so we don't really know how the
// story ends; assume success.
mInstallFlowAnalytics.setFlowFinishedWithPackageManagerResult(
PackageManager.INSTALL_SUCCEEDED);
finish();
} else {
startInstall();
}
} else {
mScrollView.pageScroll(View.FOCUS_DOWN);
}
}
虽然，我不知懂这里的mSessionId是什么含义，但是 根据代码能看出，安装一个应用应该是startInstall方法。在这个方法中，最终会去玩InstallAppProgress这个界面，对应我们安装中进度条显示的界面。有如下代码。
if ("package".equals(mPackageURI.getScheme())) {
try {
pm.installExistingPackage(mAppInfo.packageName);
observer.packageInstalled(mAppInfo.packageName,
PackageManager.INSTALL_SUCCEEDED);
} catch (PackageManager.NameNotFoundException e) {
observer.packageInstalled(mAppInfo.packageName,
PackageManager.INSTALL_FAILED_INVALID_APK);
}
} else {
pm.installPackageWithVerificationAndEncryption(mPackageURI, observer, installFlags,
installerPackageName, verificationParams, null);
}
- mPackageURI，安装应用的话，应该是file
- pm 为ApplicationPackageManager
因此，我们看installPackageWithVerificationAndEncryption方法。
3.ApplicationPackageManager#installPackageWithVerificationAndEncryption
在这个方法中，会调用installCommon方法，而installCommon方法中，会进行简单的参数校验，然后调用mPM的installPackage方法去安装。这个mPM参数实在构造的时候传入的。是通过ActivityThread.getPackageManager()获取。
public static IPackageManager getPackageManager() {
if (sPackageManager != null) {
//Slog.v("PackageManager", "returning cur default = " + sPackageManager);
return sPackageManager;
}
IBinder b = ServiceManager.getService("package");
//Slog.v("PackageManager", "default service binder = " + b);
sPackageManager = IPackageManager.Stub.asInterface(b);
//Slog.v("PackageManager", "default service = " + sPackageManager);
return sPackageManager;
}
从中可以看出，其binder服务端为PackageManagerService.
4.PackageManagerService#installPackage
在这个方法中，回调用installPackageAsUser方法。在这个方法中，会发送一个消息，执行安装过程的第一个阶段，copy
final Message msg = mHandler.obtainMessage(INIT_COPY);
msg.obj = new InstallParams(origin, null, observer, installFlags, installerPackageName,
null, verificationParams, user, packageAbiOverride, null);
mHandler.sendMessage(msg);
这里的mHandler为PackageHandler实例对象，其消息处理部分代码在doHandleMessage中，我们看INIT_COPY，做了什么？
case INIT_COPY: {
HandlerParams params = (HandlerParams) msg.obj;
int idx = mPendingInstalls.size();
if (DEBUG_INSTALL) Slog.i(TAG, "init_copy idx=" + idx + ": " + params);
// If a bind was already initiated we dont really
// need to do anything. The pending install
// will be processed later on.
if (!mBound) {
// If this is the only one pending we might
// have to bind to the service again.
if (!connectToService()) {
Slog.e(TAG, "Failed to bind to media container service");
params.serviceError();
return;
} else {
// Once we bind to the service, the first
// pending request will be processed.
mPendingInstalls.add(idx, params);
}
} else {
mPendingInstalls.add(idx, params);
// Already bound to the service. Just make
// sure we trigger off processing the first request.
if (idx == 0) {
mHandler.sendEmptyMessage(MCS_BOUND);
}
}
break;
}
如果没有绑定，就绑定，如果绑定了，将HandlerParams加入到mPendingInstalls中，并且如果以前为空，则发送MCS_BOUND这个空消息。
在接受到MCS_BOUND这个消息之后，会循环处理并且再次发送MCS_BOUND消息，
if (DEBUG_INSTALL) Slog.i(TAG, "mcs_bound");
if (msg.obj != null) {
mContainerService = (IMediaContainerService) msg.obj;
}
if (mContainerService == null) {
if (!mBound) {
// Something seriously wrong since we are not bound and we are not
// waiting for connection. Bail out.
Slog.e(TAG, "Cannot bind to media container service");
for (HandlerParams params : mPendingInstalls) {
// Indicate service bind error
params.serviceError();
}
mPendingInstalls.clear();
} else {
Slog.w(TAG, "Waiting to connect to media container service");
}
} else if (mPendingInstalls.size() > 0) {
HandlerParams params = mPendingInstalls.get(0);
if (params != null) {
if (params.startCopy()) {
// We are done... look for more work or to
// go idle.
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Checking for more work or unbind...");
// Delete pending install
if (mPendingInstalls.size() > 0) {
mPendingInstalls.remove(0);
}
if (mPendingInstalls.size() == 0) {
if (mBound) {
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Posting delayed MCS_UNBIND");
removeMessages(MCS_UNBIND);
Message ubmsg = obtainMessage(MCS_UNBIND);
// Unbind after a little delay, to avoid
// continual thrashing.
sendMessageDelayed(ubmsg, 10000);
}
} else {
// There are more pending requests in queue.
// Just post MCS_BOUND message to trigger processing
// of next pending install.
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Posting MCS_BOUND for next work");
mHandler.sendEmptyMessage(MCS_BOUND);
}
}
}
} else {
// Should never happen ideally.
Slog.w(TAG, "Empty queue");
}
break;
从上诉代码中，我们就能知道，通过params.startCopy()去执行copy操作，并且如果还有未安装的，会重复发这个消息，知道所有都安装成功。
5.HandlerParams#startCopy
final boolean startCopy() {
boolean res;
try {
if (DEBUG_INSTALL) Slog.i(TAG, "startCopy " + mUser + ": " + this);
if (++mRetries > MAX_RETRIES) {
Slog.w(TAG, "Failed to invoke remote methods on default container service. Giving up");
mHandler.sendEmptyMessage(MCS_GIVE_UP);
handleServiceError();
return false;
} else {
handleStartCopy();
res = true;
}
} catch (RemoteException e) {
if (DEBUG_INSTALL) Slog.i(TAG, "Posting install MCS_RECONNECT");
mHandler.sendEmptyMessage(MCS_RECONNECT);
res = false;
}
handleReturnCode();
return res;
}
这里有重试机制。而handleStartCopy的实现在InstallParams中。
6.InstallParams#handleStartCopy
这个方法比较长，分段来看。
final StorageManager storage = StorageManager.from(mContext);
final long lowThreshold = storage.getStorageLowBytes(
Environment.getDataDirectory());
final long sizeBytes = mContainerService.calculateInstalledSize(
origin.resolvedPath, isForwardLocked(), packageAbiOverride);
if (mInstaller.freeCache(null, sizeBytes + lowThreshold) >= 0) {
pkgLite = mContainerService.getMinimalPackageInfo(origin.resolvedPath,
installFlags, packageAbiOverride);
}
首先，如果需要的空间不够大，就调用Install的freeCache去释放一部分缓存。
这里的mContainerService对应的binder服务端实现，在DefaultContainerService中。
中间经过复杂的判断处理之后，创建一个InstallArgs对象，如果前面的判断结果是能安装成功的话，进入分支。
if (ret == PackageManager.INSTALL_SUCCEEDED) {
/*
* ADB installs appear as UserHandle.USER_ALL, and can only be performed by
* UserHandle.USER_OWNER, so use the package verifier for UserHandle.USER_OWNER.
*/
int userIdentifier = getUser().getIdentifier();
if (userIdentifier == UserHandle.USER_ALL
&& ((installFlags & PackageManager.INSTALL_FROM_ADB) != 0)) {
userIdentifier = UserHandle.USER_OWNER;
}
/*
* Determine if we have any installed package verifiers. If we
* do, then we'll defer to them to verify the packages.
*/
final int requiredUid = mRequiredVerifierPackage == null ? -1
: getPackageUid(mRequiredVerifierPackage, userIdentifier);
if (!origin.existing && requiredUid != -1
&& isVerificationEnabled(userIdentifier, installFlags)) {
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);
final List<ResolveInfo> receivers = queryIntentReceivers(verification,
PACKAGE_MIME_TYPE, PackageManager.GET_DISABLED_COMPONENTS,
0 /* TODO: Which userId? */);
if (DEBUG_VERIFY) {
Slog.d(TAG, "Found " + receivers.size() + " verifiers for intent "
+ verification.toString() + " with " + pkgLite.verifiers.length
+ " optional verifiers");
}
final int verificationId = mPendingVerificationToken++;
verification.putExtra(PackageManager.EXTRA_VERIFICATION_ID, verificationId);
verification.putExtra(PackageManager.EXTRA_VERIFICATION_INSTALLER_PACKAGE,
installerPackageName);
verification.putExtra(PackageManager.EXTRA_VERIFICATION_INSTALL_FLAGS,
installFlags);
verification.putExtra(PackageManager.EXTRA_VERIFICATION_PACKAGE_NAME,
pkgLite.packageName);
verification.putExtra(PackageManager.EXTRA_VERIFICATION_VERSION_CODE,
pkgLite.versionCode);
if (verificationParams != null) {
if (verificationParams.getVerificationURI() != null) {
verification.putExtra(PackageManager.EXTRA_VERIFICATION_URI,
verificationParams.getVerificationURI());
}
if (verificationParams.getOriginatingURI() != null) {
verification.putExtra(Intent.EXTRA_ORIGINATING_URI,
verificationParams.getOriginatingURI());
}
if (verificationParams.getReferrer() != null) {
verification.putExtra(Intent.EXTRA_REFERRER,
verificationParams.getReferrer());
}
if (verificationParams.getOriginatingUid() >= 0) {
verification.putExtra(Intent.EXTRA_ORIGINATING_UID,
verificationParams.getOriginatingUid());
}
if (verificationParams.getInstallerUid() >= 0) {
verification.putExtra(PackageManager.EXTRA_VERIFICATION_INSTALLER_UID,
verificationParams.getInstallerUid());
}
}
final PackageVerificationState verificationState = new PackageVerificationState(
requiredUid, args);
mPendingVerification.append(verificationId, verificationState);
final List<ComponentName> sufficientVerifiers = matchVerifiers(pkgLite,
receivers, verificationState);
// Apps installed for "all" users use the device owner to verify the app
UserHandle verifierUser = getUser();
if (verifierUser == UserHandle.ALL) {
verifierUser = UserHandle.OWNER;
}
/*
* 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);
final Intent sufficientIntent = new Intent(verification);
sufficientIntent.setComponent(verifierComponent);
mContext.sendBroadcastAsUser(sufficientIntent, verifierUser);
}
}
}
final ComponentName requiredVerifierComponent = matchComponentForVerifier(
mRequiredVerifierPackage, receivers);
if (ret == PackageManager.INSTALL_SUCCEEDED
&& mRequiredVerifierPackage != null) {
/*
* Send the intent to the required verification agent,
* but only start the verification timeout after the
* target BroadcastReceivers have run.
*/
verification.setComponent(requiredVerifierComponent);
mContext.sendOrderedBroadcastAsUser(verification, verifierUser,
android.Manifest.permission.PACKAGE_VERIFICATION_AGENT,
new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final Message msg = mHandler
.obtainMessage(CHECK_PENDING_VERIFICATION);
msg.arg1 = verificationId;
mHandler.sendMessageDelayed(msg, getVerificationTimeout());
}
}, null, 0, null, null);
/*
* We don't want the copy to proceed until verification
* succeeds, so null out this field.
*/
mArgs = null;
}
} else {
/*
* No package verification is enabled, so immediately start
* the remote call to initiate copy using temporary file.
*/
ret = args.copyApk(mContainerService, true);
}
}
-
如果启动了包验证的话，就会进入验证阶段。
- 发送有序广播，
- 否则，直接进行复制操作
验证部分的逻辑很长，大部分代码都是对intent进行设置。
7.InstallArgs#copyApk
在createInstallArgs中，会根据InstallParams创建不同的InstallArgs对象。
private InstallArgs createInstallArgs(InstallParams params) {
if (params.move != null) {
return new MoveInstallArgs(params);
} else if (installOnExternalAsec(params.installFlags) || params.isForwardLocked()) {
return new AsecInstallArgs(params);
} else {
return new FileInstallArgs(params);
}
}
以FileInstallArgs为例，我们来看看。
int copyApk(IMediaContainerService imcs, boolean temp) throws RemoteException {
if (origin.staged) {
if (DEBUG_INSTALL) Slog.d(TAG, origin.file + " already staged; skipping copy");
codeFile = origin.file;
resourceFile = origin.file;
return PackageManager.INSTALL_SUCCEEDED;
}
try {
final File tempDir = mInstallerService.allocateStageDirLegacy(volumeUuid);
codeFile = tempDir;
resourceFile = tempDir;
} catch (IOException e) {
Slog.w(TAG, "Failed to create copy file: " + e);
return PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
}
final IParcelFileDescript orFactory target = new IParcelFileDescript orFactory.Stub() {
@Override
public ParcelFileDescript or open(String name, int mode) throws RemoteException {
if (!FileUtils.isValidExtFilename(name)) {
throw new IllegalArgumentException("Invalid filename: " + name);
}
try {
final File file = new File(codeFile, name);
final FileDescript or fd = Os.open(file.getAbsolutePath(),
O_RDWR | O_CREAT, 0644);
Os.chmod(file.getAbsolutePath(), 0644);
return new ParcelFileDescript or(fd);
} catch (ErrnoException e) {
throw new RemoteException("Failed to open: " + e.getMessage());
}
}
};
int ret = PackageManager.INSTALL_SUCCEEDED;
ret = imcs.copyPackage(origin.file.getAbsolutePath(), target);
if (ret != PackageManager.INSTALL_SUCCEEDED) {
Slog.e(TAG, "Failed to copy package");
return ret;
}
final File libraryRoot = new File(codeFile, LIB_DIR_NAME);
NativeLibraryHelper.Handle handle = null;
try {
handle = NativeLibraryHelper.Handle.create(codeFile);
ret = NativeLibraryHelper.copyNativeBinariesWithOverride(handle, libraryRoot,
abiOverride);
} catch (IOException e) {
Slog.e(TAG, "Copying native libraries failed", e);
ret = PackageManager.INSTALL_FAILED_INTERNAL_ERROR;
} finally {
IoUtils.closeQuietly(handle);
}
return ret;
}
- 首先mInstallerService.allocateStageDirLegacy申请足够的存储空间
- 得到申请的那部分空间的文件描述符，并且修改权限
- IMediaContainerService#copyPackage 拷贝到指定目录，实现在DefaultContainerService中，
- NativeLibraryHelper#copyNativeBinariesWithOverride 拷贝二进制文件(so库)
8.DefaultContainerService#copyPackage
public int copyPackage(String packagePath, IParcelFileDescript orFactory target) { if (packagePath == null || target == null) { return PackageManager.INSTALL_FAILED_INVALID_URI; } PackageLite pkg = null; try { final File packageFile = new File(packagePath); pkg = PackageParser.parsePackageLite(packageFile, 0); return copyPackageInner(pkg, target); } catch (PackageParserException | IOException | RemoteException e) { Slog.w(TAG, "Failed to copy package at " + packagePath + ": " + e); return PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE; } }
- 解析apk文件
- 将文件拷贝到指定目录
9.NativeLibraryHelper#copyNativeBinariesWithOverride
在这个方法中，将不同的so库通过copyNativeBinariesForSupportedAbi方法copy到不同的目录。copy的具体流程就不说了。
到现在，copy的流程就完了。
在上面startCopy中，下面有handleReturnCode，是对copy后进行后续处理的，我们依然看，InstallParams的这个方法。
10.InstallParams#handleReturnCode
在这个方法中，会调用processPendingInstall去处理。
private void processPendingInstall(final InstallArgs args, final int currentStatus) {
// Queue up an async operation since the package installation may take a little while.
mHandler.post(new Runnable() {
public void run() {
mHandler.removeCallbacks(this);
// Result object to be returned
PackageInstalledInfo res = new PackageInstalledInfo();
res.returnCode = currentStatus;
res.uid = -1;
res.pkg = null;
res.removedInfo = new PackageRemovedInfo();
if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
args.doPreInstall(res.returnCode);
synchronized (mInstallLock) {
installPackageLI(args, res);
}
args.doPostInstall(res.returnCode, res.uid);
}
// A restore should be performed at this point if (a) the install
// succeeded, (b) the operation is not an update, and (c) the new
// package has not opted out of backup participation.
final boolean update = res.removedInfo.removedPackage != null;
final int flags = (res.pkg == null) ? 0 : res.pkg.applicationInfo.flags;
boolean doRestore = !update
&& ((flags & ApplicationInfo.FLAG_ALLOW_BACKUP) != 0);
// Set up the post-install work request bookkeeping. This will be used
// and cleaned up by the post-install event handling regardless of whether
// there's a restore pass performed. Token values are >= 1.
int token;
if (mNextInstallToken < 0) mNextInstallToken = 1;
token = mNextInstallToken++;
PostInstallData data = new PostInstallData(args, res);
mRunningInstalls.put(token, data);
if (DEBUG_INSTALL) Log.v(TAG, "+ starting restore round-trip " + token);
if (res.returnCode == PackageManager.INSTALL_SUCCEEDED && doRestore) {
// Pass responsibility to the Backup Manager. It will perform a
// restore if appropriate, then pass responsibility back to the
// Package Manager to run the post-install observer callbacks
// and broadcasts.
IBackupManager bm = IBackupManager.Stub.asInterface(
ServiceManager.getService(Context.BACKUP_SERVICE));
if (bm != null) {
if (DEBUG_INSTALL) Log.v(TAG, "token " + token
+ " to BM for possible restore");
try {
if (bm.isBackupServiceActive(UserHandle.USER_OWNER)) {
bm.restoreAtInstall(res.pkg.applicationInfo.packageName, token);
} else {
doRestore = false;
}
} catch (RemoteException e) {
// can't happen; the backup manager is local
} catch (Exception e) {
Slog.e(TAG, "Exception trying to enqueue restore", e);
doRestore = false;
}
} else {
Slog.e(TAG, "Backup Manager not found!");
doRestore = false;
}
}
if (!doRestore) {
// No restore possible, or the Backup Manager was mysteriously not
// available -- just fire the post-install work request directly.
if (DEBUG_INSTALL) Log.v(TAG, "No restore - queue post-install for " + token);
Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0);
mHandler.sendMessage(msg);
}
}
});
}
安装过程
- installPackageLI，在这个之前，会用doPreInstall进行cleanup操作，在这之后会用doPostInstall进行clean操作。
- 恢复部分代码 没看明白。:sob:
- 发送POST_INSTALL消息
11.installPackageLI
改方法氛围几部分。
首先是解析包过程。
PackageParser pp = new PackageParser();
pp.setSeparateProcesses(mSeparateProcesses);
pp.setDisplayMetrics(mMetrics);
final PackageParser.Package pkg;
try {
pkg = pp.parsePackage(tmpPackageFile, parseFlags);
} catch (PackageParserException e) {
res.setError("Failed parse during installPackageLI", e);
return;
}
其次是校验签名的md5的过程
try {
pp.collectCertificates(pkg, parseFlags);
pp.collectManifestDigest(pkg);
} catch (PackageParserException e) {
res.setError("Failed collect during installPackageLI", e);
return;
}
/* If the installer passed in a manifest digest, compare it now. */
if (args.manifestDigest != null) {
if (DEBUG_INSTALL) {
final String parsedManifest = pkg.manifestDigest == null ? "null"
: pkg.manifestDigest.toString();
Slog.d(TAG, "Comparing manifests: " + args.manifestDigest.toString() + " vs. "
+ parsedManifest);
}
if (!args.manifestDigest.equals(pkg.manifestDigest)) {
res.setError(INSTALL_FAILED_PACKAGE_CHANGED, "Manifest digest changed");
return;
}
} else if (DEBUG_INSTALL) {
final String parsedManifest = pkg.manifestDigest == null
? "null" : pkg.manifestDigest.toString();
Slog.d(TAG, "manifestDigest was not present, but parser got: " + parsedManifest);
}
调用installNewPackageLI安装。
12.installNewPackageLI
在这个方法中，调用scanPackageDirtyLI进行扫描，而在scanPackageDirtyLI中，经过复杂的操作之后就算完成了安装，诸如，创建用户数据目录，进行dex优化等等。
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