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Android应用安装
Android通过PackageManagerService(后面简称Pms)进行包管理,其主要功能包括:用户ID分配、包解析、包的安装卸载等。本文不对Pms进行分析,主要目的是探讨一下包安装。在本文中主要探讨包安装的相关操作,卸载作为安装的逆过程,实现类似,不再赘述。
Android中APK的安装方式
在Android中APK的安装有三种方式:
1、开机Pms初始化时,扫描包安装目录。
@/frameworks/base/services/java/com/android/server/SystemServer.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | public void initAndLoop() { ...... IPackageManager pm = null ; ...... try { ...... pm = PackageManagerService.main(context, installer, factoryTest != SystemServer.FACTORY_TEST_OFF, onlyCore); ...... } catch (RuntimeException e) { Slog.e( "System" , "******************************************" ); Slog.e( "System" , "************ Failure starting core service" , e); } ...... } |
@/frameworks/base/services/java/com/android/server/pm/PackageManagerService.java
1 2 3 4 5 6 7 | public static final IPackageManager main(Context context, Installer installer, boolean factoryTest, boolean onlyCore) { PackageManagerService m = new PackageManagerService(context, installer, factoryTest, onlyCore); ServiceManager.addService( "package" , m); return m; } |
下面是Pms构造函数的实现:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 | public PackageManagerService(Context context, Installer installer, boolean factoryTest, boolean onlyCore) { ...... synchronized (mInstallLock) { // writer synchronized (mPackages) { ...... File dataDir = Environment.getDataDirectory(); mAppDataDir = new File(dataDir, "data" ); mAppInstallDir = new File(dataDir, "app" ); mAppLibInstallDir = new File(dataDir, "app-lib" ); mAsecInternalPath = new File(dataDir, "app-asec" ).getPath(); mUserAppDataDir = new File(dataDir, "user" ); mDrmAppPrivateInstallDir = new File(dataDir, "app-private" ); ...... // Find base frameworks (resource packages without code). mFrameworkInstallObserver = new AppDirObserver( frameworkDir.getPath(), OBSERVER_EVENTS, true , false ); mFrameworkInstallObserver.startWatching(); scanDirLI(frameworkDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode | SCAN_NO_DEX, 0); // Collected privileged system packages. File privilegedAppDir = new File(Environment.getRootDirectory(), "priv-app" ); mPrivilegedInstallObserver = new AppDirObserver( privilegedAppDir.getPath(), OBSERVER_EVENTS, true , true ); mPrivilegedInstallObserver.startWatching(); scanDirLI(privilegedAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR | PackageParser.PARSE_IS_PRIVILEGED, scanMode, 0); // Collect ordinary system packages. File systemAppDir = new File(Environment.getRootDirectory(), "app" ); mSystemInstallObserver = new AppDirObserver( systemAppDir.getPath(), OBSERVER_EVENTS, true , false ); mSystemInstallObserver.startWatching(); scanDirLI(systemAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); // Collect all vendor packages. File vendorAppDir = new File( "/vendor/app" ); mVendorInstallObserver = new AppDirObserver( vendorAppDir.getPath(), OBSERVER_EVENTS, true , false ); mVendorInstallObserver.startWatching(); scanDirLI(vendorAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); ...... if (!mOnlyCore) { EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_DATA_SCAN_START, SystemClock.uptimeMillis()); mAppInstallObserver = new AppDirObserver( mAppInstallDir.getPath(), OBSERVER_EVENTS, false , false ); mAppInstallObserver.startWatching(); scanDirLI(mAppInstallDir, 0, scanMode, 0); mDrmAppInstallObserver = new AppDirObserver( mDrmAppPrivateInstallDir.getPath(), OBSERVER_EVENTS, false , false ); mDrmAppInstallObserver.startWatching(); scanDirLI(mDrmAppPrivateInstallDir, PackageParser.PARSE_FORWARD_LOCK, scanMode, 0); ...... } // synchronized (mPackages) } // synchronized (mInstallLock) } |
通过Pms的构造函数可以看出,Pms在初始化时会扫描/system/app、vender/app、/data/app、/data/app-private四个应用安装目录,然后调用sanDirLI方法进行安装。Pms通过AppDirObserver对这四个应用安装目录进行监控,一旦发现APK格式的文件则会调用scanPackageLI进行安装。
2、通过包安装器PackageInstaller安装
Android提供了一个默认的包安装器,位于/package/app/PackageInstaller目录。通过其Manifest文件可以看出,PackageInstaller会对我们安装应用发出的Intent进行处理,这里PackageInstaller提供了两种处理方式,分别是:file方式和package方式。
@/package/app/PackageInstaller/AndroidManifest.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | < activity android:name = ".PackageInstallerActivity" android:configChanges = "orientation|keyboardHidden|screenSize" android:excludeFromRecents = "true" > < intent-filter > < action android:name = "android.intent.action.VIEW" /> < action android:name = "android.intent.action.INSTALL_PACKAGE" /> < category android:name = "android.intent.category.DEFAULT" /> < data android:scheme = "file" /> < data android:mimeType = "application/vnd.android.package-archive" /> </ intent-filter > < intent-filter > < action android:name = "android.intent.action.INSTALL_PACKAGE" /> < category android:name = "android.intent.category.DEFAULT" /> < data android:scheme = "file" /> < data android:scheme = "package" /> </ intent-filter > </ activity > |
@/package/app/PackageInstaller/src/com/android/packageinstaller/PackageInstallerActivity.java
1 2 3 4 5 6 7 8 | @Override protected void onCreate(Bundle icicle) { super .onCreate(icicle); ...... initiateInstall(); } |
1 2 3 4 5 | private void initiateInstall() { ...... startInstallConfirm(); } |
在startInstallConfirm方法中点击“确认”后,会发出一个Intent,接收者为InstallAppProgress。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | public void onClick(View v) { if (v == mOk) { if (mOkCanInstall || mScrollView == null ) { // Start subactivity to actually install the application mInstallFlowAnalytics.setInstallButtonClicked(); Intent newIntent = new Intent(); newIntent.putExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO, mPkgInfo.applicationInfo); newIntent.setData(mPackageURI); newIntent.setClass( this , InstallAppProgress. class ); ...... startActivity(newIntent); finish(); } else { mScrollView.pageScroll(View.FOCUS_DOWN); } } else if (v == mCancel) { ...... } } |
@/package/app/PackageInstaller/src/com/android/packageinstaller/InstallAppProgress.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | public void initView() { setContentView(R.layout.op_progress); int installFlags = 0 ; PackageManager pm = getPackageManager(); ...... String installerPackageName = getIntent().getStringExtra( Intent.EXTRA_INSTALLER_PACKAGE_NAME); Uri originatingURI = getIntent().getParcelableExtra(Intent.EXTRA_ORIGINATING_URI); Uri referrer = getIntent().getParcelableExtra(Intent.EXTRA_REFERRER); int originatingUid = getIntent().getIntExtra(Intent.EXTRA_ORIGINATING_UID, VerificationParams.NO_UID); ManifestDigest manifestDigest = getIntent().getParcelableExtra(EXTRA_MANIFEST_DIGEST); VerificationParams verificationParams = new VerificationParams( null , originatingURI, referrer, originatingUid, manifestDigest); PackageInstallObserver observer = new PackageInstallObserver(); 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 ); } } |
InstallAppProgress即应用安装过程中的进度条界面。通过上面的代码可以看到在initView方法的最后会调用Pms的installPackageWithVerificationAndEncryption方法进行安装。
3、通过adb命令安装
adb命令pm是Pms的Shell客户端,通过pm可以进行包相关的一些操作,包括安装和卸载。pm命令的用法如下:
pm的代码实现在Pm.java中,如下:
@/frameworks/base/cmds/pm/src/com/android/commands/pm/Pm.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | public static void main(String[] args) { new Pm().run(args); } public void run(String[] args) { ...... mPm = IPackageManager.Stub.asInterface(ServiceManager.getService( "package" )); ...... if ( "install" .equals(op)) { runInstall(); return ; } if ( "uninstall" .equals(op)) { runUninstall(); return ; } ...... } |
在run方法中初始化了一个Pms的客户端代理对象mPm,后续的相关操作将有mPm完成。下面看一下Pm中负责安装的方法runInstall的代码实现:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | private void runInstall() { int installFlags = PackageManager.INSTALL_ALL_USERS; ...... while ((opt=nextOption()) != null ) { if (opt.equals( "-l" )) { installFlags |= PackageManager.INSTALL_FORWARD_LOCK; } else if (opt.equals( "-r" )) { installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; } else if (opt.equals( "-i" )) { installerPackageName = nextOptionData(); if (installerPackageName == null ) { System.err.println( "Error: no value specified for -i" ); return ; } } else if (opt.equals( "-t" )) { installFlags |= PackageManager.INSTALL_ALLOW_TEST; } else if (opt.equals( "-s" )) { // Override if -s option is specified. installFlags |= PackageManager.INSTALL_EXTERNAL; } else if (opt.equals( "-f" )) { // Override if -s option is specified. installFlags |= PackageManager.INSTALL_INTERNAL; } else if (opt.equals( "-d" )) { installFlags |= PackageManager.INSTALL_ALLOW_DOWNGRADE; ...... PackageInstallObserver obs = new PackageInstallObserver(); try { VerificationParams verificationParams = new VerificationParams(verificationURI, originatingURI, referrerURI, VerificationParams.NO_UID, null ); mPm.installPackageWithVerificationAndEncryption(apkURI, obs, installFlags, installerPackageName, verificationParams, encryptionParams); synchronized (obs) { while (!obs.finished) { try { obs.wait(); } catch (InterruptedException e) { } } if (obs.result == PackageManager.INSTALL_SUCCEEDED) { System.out.println( "Success" ); } else { System.err.println( "Failure [" + installFailureToString(obs.result) + "]" ); } } } catch (RemoteException e) { System.err.println(e.toString()); System.err.println(PM_NOT_RUNNING_ERR); } } |
可以看出runInstall最终会调用Pms的installPackageWithVerificationAndEncryption方法进行安装。通过pm安装时,安装成功的返回信息为“Success”,安装失败的返回信息为”Failure[失败信息]"。
静默安装实现
在了解了Android中包安装的方式后,接下来探讨一些如何实现”静默安装“。所谓静默安装即跳过安装界面和进度条,在不被用户察觉的情况下载后台安装。下面针对上面的三种安装方式分别来分析如何实现静默安装。
1、push安装包到应用安装目录的方式
在Pms初始化时安装包的流程中,我们知道Pms会监控/system/app、vender/app、/data/app、/data/app-private这四个应用安装目录。因此如果能够将APK文件push进应用安装目录不就可以触发AppDirObserver中的包安装逻辑了了吗?所以这种思路理论上是行得通的,但有两个局限:
局限一:如下图所示,/system/app的访问权限为root,这就要求在push到/system/app目录时必须具有root权限。
而/data/app的访问权限为system。要获得system权限就要求使用这种方式的应用程序必须签名为platform并且sharedUserId制定为“android.uid.system”。
局限二:系统应用(/system/app)与普通应用(/data/app)的安装方式是不同的,对于系统应用,所有资源都包含在apk这个zip包中,而且其在/system/app不必以包名命名(理论上可以随便起名)。
而对于普通应用安装后,它的dex、lib、资源文件(安装包)分别存放在不同的目录,并且安装后以packagename-x.apk的形式保存在/data/app目录下。?
那这种安装方式是不是就没有用了呢?非也。
网上有些电子市场或管家类软件实现的”秒装“功能应该就是安装这个思路实现的,当然这里只是猜测,需要进一步研究。
2、调用Pm隐藏API
Android实现了一个应用安装器的APK负责包的安装工作,在上面的分析中我们知道,PackageInstaller的工作实际上只是安装界面、权限确认、进度显示等,真正的安装工作依然是调用Pms实现的。到这里我们就有了第二种思路,能不能绕过安装界面,直接调用Pms里面的相应方法呢?当然可以,PackageManager类中就提供了这样的方法:
@/frameworks/base/core/java/android/content/pm/PackageManager.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | /** * @hide * * Install a package. Since this may take a little while, the result will * be posted back to the given observer. An installation will fail if the calling context * lacks the {@link android.Manifest.permission#INSTALL_PACKAGES} permission, if the * package named in the package file‘s manifest is already installed, or if there‘s no space * available on the device. * * @param packageURI The location of the package file to install. This can be a ‘file:‘ or a * ‘content:‘ URI. * @param observer An observer callback to get notified when the package installation is * complete. {@link IPackageInstallObserver#packageInstalled(String, int)} will be * called when that happens. observer may be null to indicate that no callback is desired. * @param flags - possible values: {@link #INSTALL_FORWARD_LOCK}, * {@link #INSTALL_REPLACE_EXISTING}, {@link #INSTALL_ALLOW_TEST}. * @param installerPackageName Optional package name of the application that is performing the * installation. This identifies which market the package came from. */ public abstract void installPackage( Uri packageURI, IPackageInstallObserver observer, int flags, String installerPackageName); |
可以看出,这个方法是hide的,因此在应用开发时如果要使用,必须通过反射。
这里的IPackageInstallObserver是installPackage方法的一个回调接口通知,其实现在IPackageInstallObserver.aidl中,如下:
@/frameworks/base/core/java/com/android/content/pm/IPackageInstallObserver.aidl
1 2 3 4 5 6 7 8 9 | package android.content.pm; /** * API for installation callbacks from the Package Manager. * @hide */ oneway interface IPackageInstallObserver { void packageInstalled(in String packageName, int returnCode); } |
使用Android内置未公开API有两种方法:一种是通过反射的方式实现;另一种是在工程目录下建立与所引用系统类相同的类和方法,这里只要求类和方法名相同,不需要实现,只保证编译时不报错就可以了,根据Java的类加载机制,在运行时,会去加载系统类。下面是采用第二种方法时的两段示例代码:
实现接口回调的代码如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | class MyPakcageInstallObserver extends IPackageInstallObserver.Stub { Context cxt; String appName; String filename; String pkname; public MyPakcageInstallObserver(Context c, String appName, String filename,String packagename) { this .cxt = c; this .appName = appName; this .filename = filename; this .pkname = packagename; } @Override public void packageInstalled(String packageName, int returnCode) { Log.i(TAG, "returnCode = " + returnCode); // 返回1代表安装成功 if (returnCode == 1 ) { //TODO } Intent it = new Intent(); it.setAction(CustomAction.INSTALL_ACTION); it.putExtra( "install_returnCode" , returnCode); it.putExtra( "install_packageName" , packageName); it.putExtra( "install_appName" , appName); cxt.sendBroadcast(it); } } |
调用PackageManager.java隐藏方法,代码如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | /** * 静默安装 * */ public static void autoInstallApk(Context context, String fileName, String packageName, String APPName) { Log.d(TAG, "jing mo an zhuang:" + packageName + ",fileName:" + fileName); File file = new File(fileName); int installFlags = 0 ; if (!file.exists()) return ; installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; if (hasSdcard()) { installFlags |= PackageManager.INSTALL_EXTERNAL; } PackageManager pm = context.getPackageManager(); try { IPackageInstallObserver observer = new MyPakcageInstallObserver( context, APPName, appId, fileName,packageName,type_name); Log.i(TAG, "########installFlags:" + installFlags+ "packagename:" +packageName); pm.installPackage(Uri.fromFile(file), observer, installFlags, packageName); } catch (Exception e) { } } |
这种方法也有一定的限制:
首先,要在AndroidManifest.xml中声明”android.permission.INSTALL_PACKAGES”权限;
其次,应用需要system权限。
3、调用pm命令进行安装
在adb窗口通过pm install安装包本来就是没有安装界面的,这不正是我们想要的吗?通过pm的安装方式需要取得root或system权限。
pm的安装方式有两种,一种需要root权限,示例代码如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | new Thread() { public void run() { Process process = null ; OutputStream out = null ; InputStream in = null ; try { // 请求root process = Runtime.getRuntime().exec( "su" ); out = process.getOutputStream(); // 调用安装 out.write(( "pm install -r " + currentTempFilePath + "\n" ).getBytes()); in = process.getInputStream(); int len = 0 ; byte [] bs = new byte [ 256 ]; while (- 1 != (len = in.read(bs))) { String state = new String(bs, 0 , len); if (state.equals( "Success\n" )) { //安装成功后的操作 } } } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (out != null ) { out.flush(); out.close(); } if (in != null ) { in.close(); } } catch (IOException e) { e.printStackTrace(); } } } }.start(); |
另一钟需要system权限,示例如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | new Thread() { public void run() { Process process = null ; InputStream in = null ; try { // 请求root process = Runtime.getRuntime(). exec( "pm install -r " + currentTempFilePath + "\n" ); in = process.getInputStream(); int len = 0 ; byte [] bs = new byte [ 256 ]; while (- 1 != (len = in.read(bs))) { String state = new String(bs, 0 , len); if (state.equals( "Success\n" )) { //安装成功后的操作 } } } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (in != null ) { in.close(); } } catch (IOException e) { e.printStackTrace(); } } } }.start(); |
关于system权限的获取在介绍push方式的安装时已做介绍。上面的代码只给出了比较核心的部分,在实际实现中,对返回结果的处理同样重要。