Android中应用安装分析
#1 安装方式
- 1 安装系统APK和预制APK时，通过PMS的构造函数中安装，即第一次开机时安装应用，没有安装界面。
- 2 网络下载安装，通过应用商店等，即调用PackageManager.installPackages()，有安装界面。
- 3 通过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 安装本地apk，有安装界面，由PackageInstaller系统应用安装。
上述几种方式均通过PackageInstallObserver来监听安装是否成功。
#2 安装流程分析
2.1 首次安装
首次安装即系统第一次开机时安装应用，包括系统应用和预制应用，其最主要过程在PMS构造函数中，
整个过程关键步骤大致为上述15步，与应用安装相关实际上就是扫描和安装两步。方法调用时序图如图1所示。
[图1 PMS安装应用时序图]
- 1 向动态设置中添加系统默认的共享ID（system、phone、log、nfc、bluetooth、shell、se等）。
- 2 初始化成员变量，如Installer、PackageDexOptimizer、DexManager、ArtManagerService、MoveCallbacks、OnPermissionChangeListeners等，并获取系统配置。
- 3 启动一个服务类线程。
- 4 初始化用户管理服务
- 5 将权限配置传入包管理器
- 6 清除代码路径不存在的孤立包
- 7 将系统应用权限从安装态升级为运行时
- 8 在扫描应用前，手机供应商的覆盖安装包（/overlay）
- 9 扫描应用目录，依次为特权系统目录 priv-app、普通目录 app、供应商系统目录 vendor/app等
- 10 解析存储管理器
- 11 如果是第一次开机，需要初始化用户的默认偏好应用
- 12 在启动时，为用户准备好存储空间，因为SystemUI等启动不能等待用户
- 13 安装应用，完成后检查webview，默认浏览器等。
- 14 启动PackageInstallerService
- 15 向系统组件暴露私有服务
下面我们结合代码做详细分析
- 判断应用包是否已安装，如果包名存在于uninstalled_deapp.xml中或者已安装，则直接返回null。
2.2 下载安装
下载安装可分为两部分：拷贝应用和安装应用。拷贝过程的函数调用时序图如图2所示。
【图2 下载安装应用程序时序图】
frameworks层的入口函数为PackageManager.installPackage，由应用市场APP调用，然后调用PMS.installPackageAsUser，然后发送消息INIT_COPY、MCS_BOUND开始复制，调用HandlerParams.startCopy。这个方法主要分两部分，一部分是拷贝应用的执行程序，另一部分是创建应用的数据目录，拷贝部分由handleStartCopy完成。之后调用handlerReturnCode来处理创建数据目录。拷贝部分会调用DefaultContainerService来完成，该服务为那些可能位于可删除空间上的文件提供检查和拷贝功能。当底层设置被移除时，这样设计可以防止系统进程保留打开的文件时，不被内核杀死。
handleStartcopy实现在PMS内部类InstallParams中，它的功能是调用远程方法获取包信息和安装位置，如有必要则给与默认车辆覆盖安装位置，然后基于安装位置创建安装参数。下面我们结合关键代码做进一步分析。
首先是拷贝应用过程
- 1 PMS.installPackageAsUser的功能主要是：根据uid确定installFlags，并校验权限，并构造InstallParam，然后发送INIT_COPY消息。
@Override
public void installPackageAsUser(String originPath, IPackageInstallObserver2 observer,
int installFlags, String installerPackageName, int userId) {
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INSTALL_PACKAGES, null);
final int callingUid = Binder.getCallingUid();
enforceCrossUserPermission(callingUid, userId,
true /* requireFullPermission */, true /* checkShell */, "installPackageAsUser");
if (isUserRestricted(userId, UserManager.DISALLOW_INSTALL_APPS)) {
try {
if (observer != null) {
observer.onPackageInstalled("", INSTALL_FAILED_USER_RESTRICTED, null, null);
}
} catch (RemoteException re) {
}
return;
}
if ((callingUid == Process.SHELL_UID) || (callingUid == Process.ROOT_UID)) {
installFlags |= PackageManager.INSTALL_FROM_ADB;
} else {
// Caller holds INSTALL_PACKAGES permission, so we're less strict
// about installerPackageName.
installFlags &= ~PackageManager.INSTALL_FROM_ADB;
installFlags &= ~PackageManager.INSTALL_ALL_USERS;
}
UserHandle user;
if ((installFlags & PackageManager.INSTALL_ALL_USERS) != 0) {
user = UserHandle.ALL;
} else {
user = new UserHandle(userId);
}
// Only system components can circumvent runtime permissions when installing.
if ((installFlags & PackageManager.INSTALL_GRANT_RUNTIME_PERMISSIONS) != 0
&& mContext.checkCallingOrSelfPermission(Manifest.permission
.INSTALL_GRANT_RUNTIME_PERMISSIONS) == PackageManager.PERMISSION_DENIED) {
throw new SecurityException("You need the "
+ "android.permission.INSTALL_GRANT_RUNTIME_PERMISSIONS permission "
+ "to use the PackageManager.INSTALL_GRANT_RUNTIME_PERMISSIONS flag");
}
if ((installFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0
|| (installFlags & PackageManager.INSTALL_EXTERNAL) != 0) {
throw new IllegalArgumentException(
"New installs into ASEC containers no longer supported");
}
final File originFile = new File(originPath);
final OriginInfo origin = OriginInfo.fromUntrustedFile(originFile);
final Message msg = mHandler.obtainMessage(INIT_COPY);
final VerificationInfo verificationInfo = new VerificationInfo(
null /*originatingUri*/, null /*referrer*/, -1 /*originatingUid*/, callingUid);
final InstallParams params = new InstallParams(origin, null /*moveInfo*/, observer,
installFlags, installerPackageName, null /*volumeUuid*/, verificationInfo, user,
null /*packageAbiOverride*/, null /*grantedPermissions*/,
null /*certificates*/, PackageManager.INSTALL_REASON_UNKNOWN);
params.setTraceMethod("installAsUser").setTraceCookie(System.identityHashCode(params));
msg.obj = params;
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "installAsUser",
System.identityHashCode(msg.obj));
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "queueInstall",
System.identityHashCode(msg.obj));
mHandler.sendMessage(msg);
}
- 2 之后根据Handler.doHandleMessage调用到InstallParams.handleStartCopy方法，首先检查文件和cid是否已生成，如生成则设置installFlags。
// [InstallParams.handleStartCopy]
if (origin.staged) {
if (origin.file != null) {
installFlags |= PackageManager.INSTALL_INTERNAL;
installFlags &= ~PackageManager.INSTALL_EXTERNAL;
} else if (origin.cid != null) {
installFlags |= PackageManager.INSTALL_EXTERNAL;
installFlags &= ~PackageManager.INSTALL_INTERNAL;
} else {
throw new IllegalStateException("Invalid stage location");
}
}
- 3 然后检查空间大小，如果空间不够则释放无用空间。
// [InstallParams.handleStartCopy]
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 = mContainerService.calculateInstalledSize(
origin.resolvedPath, isForwardLocked(), packageAbiOverride);
try {
mInstaller.freeCache(null, sizeBytes + lowThreshold, 0, 0);
pkgLite = mContainerService.getMinimalPackageInfo(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;
}
}
- 4 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。
// [InstallParams.handleStartCopy]
// Override with defaults if needed.
loc = installLocationPolicy(pkgLite);
if (loc == PackageHelper.RECOMMEND_FAILED_VERSION_DOWNGRADE) {
ret = PackageManager.INSTALL_FAILED_VERSION_DOWNGRADE;
} else if (!onSd && !onInt) {
// Override install location with flags
if (loc == PackageHelper.RECOMMEND_INSTALL_EXTERNAL) {
// Set the flag to install on external media.
installFlags |= PackageManager.INSTALL_EXTERNAL;
installFlags &= ~PackageManager.INSTALL_INTERNAL;
} else if (loc == PackageHelper.RECOMMEND_INSTALL_EPHEMERAL) {
if (DEBUG_EPHEMERAL) {
Slog.v(TAG, "...setting INSTALL_EPHEMERAL install flag");
}
installFlags |= PackageManager.INSTALL_INSTANT_APP;
installFlags &= ~(PackageManager.INSTALL_EXTERNAL
|PackageManager.INSTALL_INTERNAL);
} else {
// Make sure the flag for installing on external
// media is unset
installFlags |= PackageManager.INSTALL_INTERNAL;
installFlags &= ~PackageManager.INSTALL_EXTERNAL;
}
}
- 5 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。
// [InstallParams.handleStartCopy]
final Intent verification = new Intent( //构造验证Intent
Intent.ACTION_PACKAGE_NEEDS_VERIFICATION);
// ......
final PackageVerificationState verificationState = new PackageVerificationState(
requiredUid, args);
mPendingVerification.append(verificationId, verificationState);
// 获取验证器列表
final List<ComponentName> sufficientVerifiers = matchVerifiers(pkgLite,
receivers, verificationState);
DeviceIdleController.LocalService idleController = getDeviceIdleController();
final long idleDuration = getVerificationTimeout();
/*
* 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");
// 向每个验证器发送验证Intent
final Intent sufficientIntent = new Intent(verification);
sufficientIntent.setComponent(verifierComponent);
mContext.sendBroadcastAsUser(sufficientIntent, verifierUser);
}
}
}
- 6 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。
下面为安装过程入口是PMS.processPendingInstall方法，调用时序图如图3
【图3 下载安装-安装过程图】
- 1 首先启动一个新线程，然后设置安装信息，处理安装参数，开始安装，并发送关于安装状态的广播，然后处理安装完的事情，比如打印错误信息，清除临时文件等。
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.setReturnCode(currentStatus);
res.uid = -1;
res.pkg = null;
res.removedInfo = null;
if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
args.doPreInstall(res.returnCode);
synchronized (mInstallLock) {
installPackageTracedLI(args, res);
}
args.doPostInstall(res.returnCode, res.uid);
//......
}
- 2 installPackageTracedLI是安装过程的核心方法，然后调用installPackageLI.首先检查安装包的完整性并解析安装包。
//[PMS.installPackageLI]
// 完整性校验
if (instantApp && (forwardLocked || onExternal)) {
Slog.i(TAG, "Incompatible ephemeral install; fwdLocked=" + forwardLocked
+ " external=" + onExternal);
res.setReturnCode(PackageManager.INSTALL_FAILED_INSTANT_APP_INVALID);
return;
}
// 检索包设置，并解析应用
final int parseFlags = mDefParseFlags | PackageParser.PARSE_CHATTY
| PackageParser.PARSE_ENFORCE_CODE
| (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0)
| (onExternal ? PackageParser.PARSE_EXTERNAL_STORAGE : 0)
| (instantApp ? PackageParser.PARSE_IS_EPHEMERAL : 0)
| (forceSdk ? PackageParser.PARSE_FORCE_SDK : 0);
PackageParser pp = new PackageParser();
pp.setSeparateProcesses(mSeparateProcesses);
pp.setDisplayMetrics(mMetrics);
pp.setCallback(mPackageParserCallback);
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "parsePackage");
final PackageParser.Package pkg;
try {
//解析安装包
pkg = pp.parsePackage(tmpPackageFile, parseFlags);
DexMetadataHelper.validatePackageDexMetadata(pkg);
} catch (PackageParserException e) {
res.setError("Failed parse during installPackageLI", e);
return;
} finally {
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
- 3 检查SDK版本和沙箱版本，同时检查是否有静态共享库，如有则需要放在内部存储中。
//[PMS.installPackageLI]
//检查SDK版本和沙箱版本
if (instantApp && pkg.applicationInfo.targetSdkVersion <= Build.VERSION_CODES.N_MR1) {
Slog.w(TAG, "Instant app package " + pkg.packageName + " does not target O");
res.setError(INSTALL_FAILED_SANDBOX_VERSION_DOWNGRADE,
"Instant app package must target O");
return;
}
if (instantApp && pkg.applicationInfo.targetSandboxVersion != 2) {
Slog.w(TAG, "Instant app package " + pkg.packageName
+ " does not target targetSandboxVersion 2");
res.setError(INSTALL_FAILED_SANDBOX_VERSION_DOWNGRADE,
"Instant app package must use targetSanboxVersion 2");
return;
}
//检查是否有静态共享库
if (pkg.applicationInfo.isStaticSharedLibrary()) {
// Static shared libraries have synthetic package names
renameStaticSharedLibraryPackage(pkg);
// No static shared libs on external storage
if (onExternal) {
Slog.i(TAG, "Static shared libs can only be installed on internal storage.");
res.setError(INSTALL_FAILED_INVALID_INSTALL_LOCATION,
"Packages declaring static-shared libs cannot be updated");
return;
}
}
- 4 检查是否有子安装包，如有则子安装包也需要检测。
//[PMS.installPackageLI]
// If we are installing a clustered package add results for the children
if (pkg.childPackages != null) {
synchronized (mPackages) {
final int childCount = pkg.childPackages.size();
for (int i = 0; i < childCount; i++) {
PackageParser.Package childPkg = pkg.childPackages.get(i);
PackageInstalledInfo childRes = new PackageInstalledInfo();
childRes.setReturnCode(PackageManager.INSTALL_SUCCEEDED);
childRes.pkg = childPkg;
childRes.name = childPkg.packageName;
PackageSetting childPs = mSettings.getPackageLPr(childPkg.packageName);
if (childPs != null) {
childRes.origUsers = childPs.queryInstalledUsers(
sUserManager.getUserIds(), true);
}
if ((mPackages.containsKey(childPkg.packageName))) {
childRes.removedInfo = new PackageRemovedInfo(this);
childRes.removedInfo.removedPackage = childPkg.packageName;
childRes.removedInfo.installerPackageName = childPs.installerPackageName;
}
if (res.addedChildPackages == null) {
res.addedChildPackages = new ArrayMap<>();
}
res.addedChildPackages.put(childPkg.packageName, childRes);
}
}
}
- 5 检查安装包是否已存在，如已存在则需要检查旧的父包、沙箱、sdk等是否已为空，否则会报错。
- 6 校验安装包签名
//[PMS.installPackageLI]
PackageSetting signatureCheckPs = ps;
if (pkg.applicationInfo.isStaticSharedLibrary()) {
SharedLibraryEntry libraryEntry = getLatestSharedLibraVersionLPr(pkg);
if (libraryEntry != null) {
signatureCheckPs = mSettings.getPackageLPr(libraryEntry.apk);
}
}
// Quick sanity check that we're signed correctly if updating;
// we'll check this again later when scanning, but we want to
// bail early here before tripping over redefined permissions.
if (shouldCheckUpgradeKeySetLP(signatureCheckPs, scanFlags)) {
if (!checkUpgradeKeySetLP(signatureCheckPs, pkg)) {
res.setError(INSTALL_FAILED_UPDATE_INCOMPATIBLE, "Package "
+ pkg.packageName + " upgrade keys do not match the "
+ "previously installed version");
return;
}
} else {
try {
verifySignaturesLP(signatureCheckPs, pkg);
} catch (PackageManagerException e) {
res.setError(e.error, e.getMessage());
return;
}
}
- 7 设置相关的全向，包括生成权限、移植权限等
- 8 如果这是一个系统应用，则检查是否在外部存储上或是是否被其他应用替换等
//[PMS.installPackageLI]
if (systemApp) {
if (onExternal) {
// Abort update; system app can't be replaced with app on sdcard
res.setError(INSTALL_FAILED_INVALID_INSTALL_LOCATION,
"Cannot install updates to system apps on sdcard");
return;
} else if (instantApp) {
// Abort update; system app can't be replaced with an instant app
res.setError(INSTALL_FAILED_INSTANT_APP_INVALID,
"Cannot update a system app with an instant app");
return;
}
}
- 9 生成安装包Abi(Application binary interface，应用二进制接口，描述应用程序和操作系统之间或其他应用程序的低级接口)
//[PMS.installPackageLI]
try {
String abiOverride = (TextUtils.isEmpty(pkg.cpuAbiOverride) ?
args.abiOverride : pkg.cpuAbiOverride);
final boolean extractNativeLibs = !pkg.isLibrary();
derivePackageAbi(pkg, new File(pkg.codePath), abiOverride,
extractNativeLibs, mAppLib32InstallDir);
} catch (PackageManagerException pme) {
Slog.e(TAG, "Error deriving application ABI", pme);
res.setError(INSTALL_FAILED_INTERNAL_ERROR, "Error deriving application ABI");
return;
}
- 10更新共享库
//[PMS.installPackageLI]
synchronized (mPackages) {
try {
updateSharedLibrariesLPr(pkg, null);
} catch (PackageManagerException e) {
Slog.e(TAG, "updateAllSharedLibrariesLPw failed: " + e.getMessage());
}
}
- 11如有必要，优化dex文件
//[PMS.installPackageLI]
final boolean performDexopt = (res.returnCode == PackageManager.INSTALL_SUCCEEDED)
&& !forwardLocked
&& !pkg.applicationInfo.isExternalAsec()
&& (!instantApp || Global.getInt(mContext.getContentResolver(),
Global.INSTANT_APP_DEXOPT_ENABLED, 0) != 0)
&& ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_DEBUGGABLE) == 0);
if (performDexopt) {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "dexopt");
// Do not run PackageDexOptimizer through the local performDexOpt
// method because `pkg` may not be in `mPackages` yet.
//
// Also, don't fail application installs if the dexopt step fails.
DexoptOptions dexoptOptions = new DexoptOptions(pkg.packageName,
REASON_INSTALL,
DexoptOptions.DEXOPT_BOOT_COMPLETE |
DexoptOptions.DEXOPT_INSTALL_WITH_DEX_METADATA_FILE);
mPackageDexOptimizer.performDexOpt(pkg, pkg.usesLibraryFiles,
null /* instructionSets */,
getOrCreateCompilerPackageStats(pkg),
mDexManager.getPackageUseInfoOrDefault(pkg.packageName),
dexoptOptions);
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
- 12替换安装，则直接安装新包，这里应用时生成应用数据目录。ps：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，同事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。
try (PackageFreezer freezer = freezePackageForInstall(pkgName, installFlags,
"installPackageLI")) {
if (replace) {
if (pkg.applicationInfo.isStaticSharedLibrary()) {
// Static libs have a synthetic package name containing the version
// and cannot be updated as an update would get a new package name,
// unless this is the exact same version code which is useful for
// development.
PackageParser.Package existingPkg = mPackages.get(pkg.packageName);
if (existingPkg != null && existingPkg.mVersionCode != pkg.mVersionCode) {
res.setError(INSTALL_FAILED_DUPLICATE_PACKAGE, "Packages declaring "
+ "static-shared libs cannot be updated");
return;
}
}
replacePackageLIF(pkg, parseFlags, scanFlags | SCAN_REPLACING, args.user,
installerPackageName, res, args.installReason);
} else {
installNewPackageLIF(pkg, parseFlags, scanFlags | SCAN_DELETE_DATA_ON_FAILURES,
args.user, installerPackageName, volumeUuid, res, args.installReason);
}
}
- 13 如果是安装一个不存在的包，则调用PMS.installNewPackageLIF方法。首先会检查是否有重复的包名，并更新设置，然后根据安装的结果，如果安装失败则删除安装过程中产生的文件。
private void installNewPackageLIF(PackageParser.Package pkg, final int policyFlags,
int scanFlags, UserHandle user, String installerPackageName, String volumeUuid,
PackageInstalledInfo res, int installReason) {
Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "installNewPackage");
// Remember this for later, in case we need to rollback this install
String pkgName = pkg.packageName;
if (DEBUG_INSTALL) Slog.d(TAG, "installNewPackageLI: " + pkg);
synchronized(mPackages) {
final String renamedPackage = mSettings.getRenamedPackageLPr(pkgName);
if (renamedPackage != null) {
// 如果已有相同包名的应用，则报错
res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName
+ " without first uninstalling package running as "
+ renamedPackage);
return;
}
if (mPackages.containsKey(pkgName)) {
// Don't allow installation over an existing package with the same name.
res.setError(INSTALL_FAILED_ALREADY_EXISTS, "Attempt to re-install " + pkgName
+ " without first uninstalling.");
return;
}
}
try {
PackageParser.Package newPackage = scanPackageTracedLI(pkg, policyFlags, scanFlags, System.currentTimeMillis(), user);
updateSettingsLI(newPackage, installerPackageName, null, res, user, installReason);
if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
prepareAppDataAfterInstallLIF(newPackage);
} else {
// Remove package from internal structures, but keep around any
// data that might have already existed
deletePackageLIF(pkgName, UserHandle.ALL, false, null,
PackageManager.DELETE_KEEP_DATA, res.removedInfo, true, null);
}
} catch (PackageManagerException e) {
res.setError("Package couldn't be installed in " + pkg.codePath, e);
}
Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
}
- 14 然后为已安装的应用准备数据目录，其依次的顺序是
- PMS.prepareAppDataAfterInstallLIF
- PMS.prepareAppDataLIF
- PMS.prepareAppDataLeafLIF
- Installer.createAppData
这个方法是PMS与Installer交互的接口函数，这里的数据目录是CE类型。
private void prepareAppDataLeafLIF(PackageParser.Package pkg, int userId, int flags) {
if (DEBUG_APP_DATA) {
Slog.v(TAG, "prepareAppData for " + pkg.packageName + " u" + userId + " 0x"
+ Integer.toHexString(flags));
}
final String volumeUuid = pkg.volumeUuid;
final String packageName = pkg.packageName;
final ApplicationInfo app = pkg.applicationInfo;
final int appId = UserHandle.getAppId(app.uid);
Preconditions.checkNotNull(app.seInfo);
long ceDataInode = -1;
try {
// 调用Installd守护进程的入口
ceDataInode = mInstaller.createAppData(volumeUuid, packageName, userId, flags,
appId, app.seInfo, app.targetSdkVersion);
} catch (InstallerException e) {
//......
}
// Prepare the application profiles.
mArtManagerService.prepareAppProfiles(pkg, userId);
if ((flags & StorageManager.FLAG_STORAGE_CE) != 0 && ceDataInode != -1) {
// TODO: mark this structure as dirty so we persist it!
synchronized (mPackages) {
final PackageSetting ps = mSettings.mPackages.get(packageName);
if (ps != null) {
ps.setCeDataInode(ceDataInode, userId);
}
}
}
prepareAppDataContentsLeafLIF(pkg, userId, flags);
}
- 15 如果是替换应用，一般情况是应用更新，或者是重新安装。它的主要过程包括：验证签名，如是系统更新则还需要校验hash值，检查共享ID的更改情况，不允许完整更新，更新已被删除数据，最后根据应用是否是系统应用来判断接下去的操作。
private void replacePackageLIF(PackageParser.Package pkg, final int policyFlags, int scanFlags,
UserHandle user, String installerPackageName, PackageInstalledInfo res,
int installReason) {
final boolean isInstantApp = (scanFlags & SCAN_AS_INSTANT_APP) != 0;
final PackageParser.Package oldPackage;
final PackageSetting ps;
final String pkgName = pkg.packageName;
final int[] allUsers;
final int[] installedUsers;
// ......
boolean sysPkg = (isSystemApp(oldPackage));
if (sysPkg) {
// Set the system/privileged flags as needed
final boolean privileged =
(oldPackage.applicationInfo.privateFlags
& ApplicationInfo.PRIVATE_FLAG_PRIVILEGED) != 0;
final int systemPolicyFlags = policyFlags
| PackageParser.PARSE_IS_SYSTEM
| (privileged ? PackageParser.PARSE_IS_PRIVILEGED : 0);
replaceSystemPackageLIF(oldPackage, pkg, systemPolicyFlags, scanFlags,
user, allUsers, installerPackageName, res, installReason);
} else {
replaceNonSystemPackageLIF(oldPackage, pkg, policyFlags, scanFlags,
user, allUsers, installerPackageName, res, installReason);
}
}
- 16 最后这两个方法均会调用到PMS.prepareAppDataLeafLIF。
- 17 安装完成后，更新设置，更新安装锁等。
2.3 adb安装
关于adb安装，其copy过程与下载安装不同，但安装过程却与下载过程是相同的，这里不做重复分析，需要注意的是adb安装是不能替换安装的，具体原因？
拷贝过程
其调用时序图如图4 所示。
【图4 adb安装-copy过程时序图】
- 1 adb的入口在com.android.commands.pm.Pm类，那么这是如何调用到这个类的呢，这是adb命令通过adbd守护进程调用到/system/bin/pm这个脚本，其脚本源码如下：
base=/system
export CLASSPATh-$base/framework/pm.jar
exec app_process $base/bin.com.android.commands.pm.Pm "$@"
- 2 Pm类通过脚本启动，执行顺序是main->run->runInstall，然后提交session。
public static void main(String[] args) {
int exitCode = 1;
try {
exitCode = new Pm().run(args);
} catch (Exception e) {
Log.e(TAG, "Error", e);
System.err.println("Error: " + e);
if (e instanceof RemoteException) {
System.err.println(PM_NOT_RUNNING_ERR);
}
}
System.exit(exitCode);
}
public int run(String[] args) throws RemoteException {
boolean validCommand = false;
if (args.length < 1) {
return showUsage();
}
mAm = IAccountManager.Stub.asInterface(ServiceManager.getService(Context.ACCOUNT_SERVICE));
mUm = IUserManager.Stub.asInterface(ServiceManager.getService(Context.USER_SERVICE));
mPm = IPackageManager.Stub.asInterface(ServiceManager.getService("package"));
if (mPm == null) {
System.err.println(PM_NOT_RUNNING_ERR);
return 1;
}
mInstaller = mPm.getPackageInstaller();
mArgs = args;
String op = args[0];
mNextArg = 1;
//......
if ("install".equals(op)) {
return runInstall();
}
//......
}
- 3 Pm.runInstall中首先是创建session，然后提交session，代码如下。
private int runInstall() throws RemoteException {
long startedTime = SystemClock.elapsedRealtime();
final InstallParams params = makeInstallParams();
final String inPath = nextArg();
if (params.sessionParams.sizeBytes == -1 && !STDIN_PATH.equals(inPath)) {
File file = new File(inPath);
if (file.isFile()) {
try {
ApkLite baseApk = PackageParser.parseApkLite(file, 0);
PackageLite pkgLite = new PackageLite(null, baseApk, null, null, null, null,
null, null);
params.sessionParams.setSize(
PackageHelper.calculateInstalledSize(pkgLite, false,
params.sessionParams.abiOverride));
} catch (PackageParserException | IOException e) {
System.err.println("Error: Failed to parse APK file: " + e);
return 1;
}
} else {
System.err.println("Error: Can't open non-file: " + inPath);
return 1;
}
}
final int sessionId = doCreateSession(params.sessionParams,
params.installerPackageName, params.userId);
try {
if (inPath == null && params.sessionParams.sizeBytes == -1) {
System.err.println("Error: must either specify a package size or an APK file");
return 1;
}
if (doWriteSession(sessionId, inPath, params.sessionParams.sizeBytes, "base.apk",
false /*logSuccess*/) != PackageInstaller.STATUS_SUCCESS) {
return 1;
}
Pair<String, Integer> status = doCommitSession(sessionId, false /*logSuccess*/);
if (status.second != PackageInstaller.STATUS_SUCCESS) {
return 1;
}
Log.i(TAG, "Package " + status.first + " installed in " + (SystemClock.elapsedRealtime()
- startedTime) + " ms");
System.out.println("Success");
return 0;
} finally {
try {
mInstaller.abandonSession(sessionId);
} catch (Exception ignore) {
}
}
}
- 4 这里Pm相当于客户端，接受session的服务端在PackageInstallerSession中，这里利用AIDL来完成传输，其调用过程为：
- Pm.doCommitSession
- PackageInstaller.Session.commit
- IPackageInstallerSession.commit
- PackageInstallerSession.commit
- Handler.Callback.handleMessage
- PackageInstallerSession.commitLock
- PMS.installStage
以上关于session传递过程暂不分析，下面我们来详细看下installStage方法。
- 5 installStage方法主要功能就是构造InstallParam对象，并发送INIT_COPY。
void installStage(String packageName, File stagedDir, String stagedCid,
IPackageInstallObserver2 observer, PackageInstaller.SessionParams sessionParams,
String installerPackageName, int installerUid, UserHandle user,
Certificate[][] certificates) {
if (DEBUG_EPHEMERAL) {
if ((sessionParams.installFlags & PackageManager.INSTALL_INSTANT_APP) != 0) {
Slog.d(TAG, "Ephemeral install of " + packageName);
}
}
final VerificationInfo verificationInfo = new VerificationInfo(
sessionParams.originatingUri, sessionParams.referrerUri,
sessionParams.originatingUid, installerUid);
final OriginInfo origin;
if (stagedDir != null) {
origin = OriginInfo.fromStagedFile(stagedDir);
} else {
origin = OriginInfo.fromStagedContainer(stagedCid);
}
final Message msg = mHandler.obtainMessage(INIT_COPY);
final int installReason = fixUpInstallReason(installerPackageName, installerUid,
sessionParams.installReason);
final InstallParams params = new InstallParams(origin, null, observer,
sessionParams.installFlags, installerPackageName, sessionParams.volumeUuid,
verificationInfo, user, sessionParams.abiOverride,
sessionParams.grantedRuntimePermissions, certificates, installReason);
params.setTraceMethod("installStage").setTraceCookie(System.identityHashCode(params));
msg.obj = params;
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "installStage",
System.identityHashCode(msg.obj));
Trace.asyncTraceBegin(TRACE_TAG_PACKAGE_MANAGER, "queueInstall",
System.identityHashCode(msg.obj));
mHandler.sendMessage(msg);
}
- 6 发送完Handler消息后就与下载安装过程相同了。
2.4 本地安装
本地安装参与对象包括PackageInstaller应用，PMS两部分。下面我们就来分析下PackageInstaller是如何调用到PMS中的。函数调用时序图如图5所示。
【图5 本地安装前提调用时序图】
- 1 点击文件管理器中的apk文件时，会调用到FolderFragment类的openFile方法，然后调用startActivitySafety方法启动PackageInstallerActivity。
private void openFile(File f) {
final Uri fileUri = Uri.fromFile(f);
final Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
intent.putExtra(Intent.EXTRA_TITLE, f.getName());
intent.putExtra(EXTRA_ALL_VIDEO_FOLDER, true);
Uri contentUri = null;
String type = getMIMEType(f);
//......
if (contentUri != null) {
intent.setDataAndType(contentUri, type);
} else {
intent.setDataAndType(fileUri, type);
}
try {
startActivitySafely(intent);
}
//......
}
- 2 如下为PackageInstallerActivity.onCreate方法源码，其主要过程初始化各个服务的成员变量如PMS，校验session，并加载UI界面，然用户确定是否安装。
//[PackageInstallerActivity.java]
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
if (icicle != null) {
mAllowUnknownSources = icicle.getBoolean(ALLOW_UNKNOWN_SOURCES_KEY);
}
//初始化各个关键参数
mPm = getPackageManager();
mIpm = AppGlobals.getPackageManager();
mAppOpsManager = (AppOpsManager) getSystemService(Context.APP_OPS_SERVICE);
mInstaller = mPm.getPackageInstaller();
mUserManager = (UserManager) getSystemService(Context.USER_SERVICE);
final Intent intent = getIntent();
mCallingPackage = intent.getStringExtra(EXTRA_CALLING_PACKAGE);
mSourceInfo = intent.getParcelableExtra(EXTRA_ORIGINAL_SOURCE_INFO);
mOriginatingUid = intent.getIntExtra(Intent.EXTRA_ORIGINATING_UID,
PackageInstaller.SessionParams.UID_UNKNOWN);
mOriginatingPackage = (mOriginatingUid != PackageInstaller.SessionParams.UID_UNKNOWN)
? getPackageNameForUid(mOriginatingUid) : null;
final Uri packageUri;
//校验session
if (PackageInstaller.ACTION_CONFIRM_PERMISSIONS.equals(intent.getAction())) {
final int sessionId = intent.getIntExtra(PackageInstaller.EXTRA_SESSION_ID, -1);
final PackageInstaller.SessionInfo info = mInstaller.getSessionInfo(sessionId);
if (info == null || !info.sealed || info.resolvedBaseCodePath == null) {
Log.w(TAG, "Session " + mSessionId + " in funky state; ignoring");
finish();
return;
}
mSessionId = sessionId;
packageUri = Uri.fromFile(new File(info.resolvedBaseCodePath));
mOriginatingURI = null;
mReferrerURI = null;
} else {
mSessionId = -1;
packageUri = intent.getData();
mOriginatingURI = intent.getParcelableExtra(Intent.EXTRA_ORIGINATING_URI);
mReferrerURI = intent.getParcelableExtra(Intent.EXTRA_REFERRER);
}
// if there's nothing to do, quietly slip into the ether
if (packageUri == null) {
Log.w(TAG, "Unspecified source");
setPmResult(PackageManager.INSTALL_FAILED_INVALID_URI);
finish();
return;
}
if (DeviceUtils.isWear(this)) {
showDialogInner(DLG_NOT_SUPPORTED_ON_WEAR);
return;
}
boolean wasSetUp = processPackageUri(packageUri);
if (!wasSetUp) {
return;
}
// 加载UI界面
bindUi(R.layout.install_confirm, false);
checkIfAllowedAndInitiateInstall();
}
- 3 当用户点击安装按钮时，响应函数为PackageInstallerActivity.onClick方法，
//[PackageInstallerActivity.java]
public void onClick(View v) {
if (v == mOk) {
if (mOk.isEnabled()) {
if (mOkCanInstall || mScrollView == null) {
if (mSessionId != -1) {
mInstaller.setPermissionsResult(mSessionId, true);
finish();
} else {
startInstall();
}
} else {
mScrollView.pageScroll(View.FOCUS_DOWN);
}
}
} else if (v == mCancel) {
// Cancel and finish
setResult(RESULT_CANCELED);
if (mSessionId != -1) {
mInstaller.setPermissionsResult(mSessionId, false);
}
finish();
}
}
- 4 之后调用 PackageInstallerActivity.startInstall方法，构造Intent，然后启动InstallInstalling，并销毁PackageInstallerActivity。
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(localLOGV) Log.i(TAG, "downloaded app uri="+mPackageURI);
startActivity(newIntent);
finish();
}
- 5 之后启动InstallInstalling，因为Activity中的默认成员方法的执行顺序是onCreate->onStart->onResume...其中onCreate的方法中主要过程包括：
- 1 获取待安装应用信息
- 2 根据应用安装与否决定如何调用方法
- 3 如果已存在，则直接调用PackageManager.installExistingPackage
- 4 如果不存在则构造session
- 5 之后则为安装事件广播添加一个监测
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.install_installing);
// 获取待安装应用信息
ApplicationInfo appInfo = getIntent()
.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO);
mPackageURI = getIntent().getData();
// 如果应用已存在，则使用这条路径安装
if ("package".equals(mPackageURI.getScheme())) {
try {
getPackageManager().installExistingPackage(appInfo.packageName);
launchSuccess();
} catch (PackageManager.NameNotFoundException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
} else { //否则使用session提交安装应用
final File sourceFile = new File(mPackageURI.getPath());
PackageUtil.initSnippetForNewApp(this, PackageUtil.getAppSnippet(this, appInfo,
sourceFile), R.id.app_snippet);
// 如果session已存在，则获取sessionId等数据
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 {
InstallEventReceiver.addObserver(this, mInstallId,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
// Does not happen
}
} else { // 否则创建session
PackageInstaller.SessionParams params = new PackageInstaller.SessionParams(
PackageInstaller.SessionParams.MODE_FULL_INSTALL);
// ......
try {
mInstallId = InstallEventReceiver
.addObserver(this, EventResultPersister.GENERATE_NEW_ID,
this::launchFinishBasedOnResult);
} catch (EventResultPersister.OutOfIdsException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
//创建session
try {
mSessionId = getPackageManager().getPackageInstaller().createSession(params);
} catch (IOException e) {
launchFailure(PackageManager.INSTALL_FAILED_INTERNAL_ERROR, null);
}
}
//......
mSessionCallback = new InstallSessionCallback();
}
}
- 6 InstallInstalling.onStart中注册回调函数，然后onResume中执行AsyncTask。
@Override
protected void onResume() {
super.onResume();
// This is the first onResume in a single life of the activity
if (mInstallingTask == null) {
PackageInstaller installer = getPackageManager().getPackageInstaller();
PackageInstaller.SessionInfo sessionInfo = installer.getSessionInfo(mSessionId);
//如果session非空，则执行AsyncTask
if (sessionInfo != null && !sessionInfo.isActive()) {
mInstallingTask = new InstallingAsyncTask();
mInstallingTask.execute();
} else {
// we will receive a broadcast when the install is finished
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
}
}
}
- 7 AsyncTask是Android提供的一种轻量级的异步类，执行过程可以表示为5个阶段。
- 1 准备执行，onPreExecute()
- 2 正在后台执行，doInBackgroud()
- 3 进度更新，onProcessUpdate()
- 4 完成后台任务，onPostExecute()
- 5 取消任务，onCacelled()
此处重写了方法onPostExecute方法，源码如下。
@Override
protected void onPostExecute(PackageInstaller.Session session) {
if (session != null) {
Intent broadcastIntent = new Intent(BROADCAST_ACTION);
broadcastIntent.setFlags(Intent.FLAG_RECEIVER_FOREGROUND);
broadcastIntent.setPackage(
getPackageManager().getPermissionControllerPackageName());
broadcastIntent.putExtra(EventResultPersister.EXTRA_ID, mInstallId);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
InstallInstalling.this,
mInstallId,
broadcastIntent,
PendingIntent.FLAG_UPDATE_CURRENT);
//提交session
session.commit(pendingIntent.getIntentSender());
mCancelButton.setEnabled(false);
setFinishOnTouchOutside(false);
} else {
getPackageManager().getPackageInstaller().abandonSession(mSessionId);
if (!isCancelled()) {
launchFailure(PackageManager.INSTALL_FAILED_INVALID_APK, null);
}
}
}
- 8 session对象传输顺序为：
- 1 PackageInstaller.Session.commit
- 2 IPackageInstallerSession.commit
- 3 PackageInstallerSession.commit
- 4 Handler.Callback.handleMessage
- 5 PackageInstallerSession.commitLock
- 6 PMS.installStage
这里是不是似曾相识，这一步跟Adb安装的第4步几乎相同，之后就调用installStage方法完成安装。
#3 总结
安装应用的场景就是上述所示的PMS构造函数安装、adb安装、网络下载安装、本地安装。其最终的入口为PMS.prepareAppDataLeafLIF，然后调用Installer类完成安装，这里涉及到System_server到Installd守护进程的转移。
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