Android应用程序安装过程解析(源码解析)

    xiaoxiao2021-03-26  9

    Android应用程序安装过程解析

    1.程序安装的4大步骤

    (1) 拷贝apk文件到指定目录

    在Android系统中,apk安装文件是会被保存起来的,默认情况下,用户安装的apk首先会被拷贝到 /data/app 目录下。

    /data/app目录是用户有权限访问的目录,在安装apk的时候会自动选择该目录存放用户安装的文件,而系统出厂的apk文件则被放到了 /system 分区下,包括 /system/app,/system/vendor/app,以及 /system/priv-app 等等,该分区只有Root权限的用户才能访问,这也就是为什么在没有Root手机之前,我们无法删除系统出厂的app的原因了。

    (2) 解压apk,拷贝文件,创建应用的数据目录

    为了加快app的启动速度,apk在安装的时候,会首先将app的可执行文件(dex)拷贝到 /data/dalvik-cache 目录,缓存起来。

    然后,在/data/data/目录下创建应用程序的数据目录(以应用的包名命名),存放应用的相关数据,如数据库、xml文件、cache、二进制的so动态库等等。

    (3) 解析apk的AndroidManifinest.xml文件

    Android系统中,也有一个类似注册表的东西,用来记录当前所有安装的应用的基本信息,每次系统安装或者卸载了任何apk文件,都会更新这个文件。这个文件位于如下目录:

    /data/system/packages.xml

    系统在安装apk的过程中,会解析apk的AndroidManifinest.xml文件,提取出这个apk的重要信息写入到packages.xml文件中,这些信息包括:权限、应用包名、APK的安装位置、版本、userID等等。

    由此,我们就知道了为啥一些应用市场和软件管理类的app能够很清楚地知道当前手机所安装的所有的app,以及这些app的详细信息了。

    另外一件事就是Linux的用户Id和用户组Id,以便他可以获得合适的运行权限。

    以上这些都是由PackageServiceManager完成的,下面我们会重点介绍PackageServiceManager。

    (4) 显示快捷方式

    这些应用程序只是相当于在PackageManagerService服务注册好了,如果我们想要在Android桌面上看到这些应用程序,还需要有一个Home应用程序,负责从PackageManagerService服务中把这些安装好的应用程序取出来,并以友好的方式在桌面上展现出来,例如以快捷图标的形式。在Android系统中,负责把系统中已经安装的应用程序在桌面中展现出来的Home应用程序就是Launcher了

    2.PackageManagerService的启动过程

    Android系统在启动的过程中,会启动一个应用程序管理服务PackageManagerService,这个服务负责扫描系统中特定的目录,找到里面的应用程序文件,即以Apk为后缀的文件,然后对这些文件进解析,得到应用程序的相关信息。

    应用程序管理服务PackageManagerService安装应用程序的过程,其实就是解析析应用程序配置文件AndroidManifest.xml的过程,并从里面得到得到应用程序的相关信息,例如得到应用程序的组件Activity、Service、Broadcast Receiver和Content Provider等信息,有了这些信息后,通过ActivityManagerService这个服务,我们就可以在系统中正常地使用这些应用程序了。

    应用程序管理服务PackageManagerService是系统启动的时候由SystemServer组件启动的,启后它就会执行应用程序安装的过程,因此,本文将从SystemServer启动PackageManagerService服务的过程开始分析系统中的应用程序安装的过程。

    下面我们具体分析每一个步骤。

    ##Step 1. SystemServer.main 这个函数定义在frameworks/base/services/Java/com/android/server/SystemServer.java文件中: [java] view plain copy public class SystemServer { ...... native public static void init1(String[] args); ...... public static void main(String[] args) { ...... init1(args); ...... } ...... } SystemServer组件是由Zygote进程负责启动的,启动的时候就会调用它的main函数,这个函数主要调用了JNI方法init1来做一些系统初始化的工作。 ##Step 2. SystemServer.init1 这个函数是一个JNI方法,实现在 frameworks/base/services/jni/com_android_server_SystemServer.cpp文件中: [cpp] view plain copy namespace android { extern "C" int system_init(); static void android_server_SystemServer_init1(JNIEnv* env, jobject clazz) { system_init(); } /* * JNI registration. */ static JNINativeMethod gMethods[] = { /* name, signature, funcPtr */ { "init1", "([Ljava/lang/String;)V", (void*) android_server_SystemServer_init1 }, }; int register_android_server_SystemServer(JNIEnv* env) { return jniRegisterNativeMethods(env, "com/android/server/SystemServer", gMethods, NELEM(gMethods)); } }; // namespace android 这个函数很简单,只是调用了system_init函数来进一步执行操作。 ##Step 3. libsystem_server.system_init 函数system_init实现在libsystem_server库中,源代码位于frameworks/base/cmds/system_server/library/system_init.cpp文件中: [cpp] view plain copy extern "C" status_t system_init() { LOGI("Entered system_init()"); sp<ProcessState> proc(ProcessState::self()); sp<IServiceManager> sm = defaultServiceManager(); LOGI("ServiceManager: %p\n", sm.get()); sp<GrimReaper> grim = new GrimReaper(); sm->asBinder()->linkToDeath(grim, grim.get(), 0); char propBuf[PROPERTY_VALUE_MAX]; property_get("system_init.startsurfaceflinger", propBuf, "1"); if (strcmp(propBuf, "1") == 0) { // Start the SurfaceFlinger SurfaceFlinger::instantiate(); } // Start the sensor service SensorService::instantiate(); // On the simulator, audioflinger et al don't get started the // same way as on the device, and we need to start them here if (!proc->supportsProcesses()) { // Start the AudioFlinger AudioFlinger::instantiate(); // Start the media playback service MediaPlayerService::instantiate(); // Start the camera service CameraService::instantiate(); // Start the audio policy service AudioPolicyService::instantiate(); } // And now start the Android runtime. We have to do this bit // of nastiness because the Android runtime initialization requires // some of the core system services to already be started. // All other servers should just start the Android runtime at // the beginning of their processes's main(), before calling // the init function. LOGI("System server: starting Android runtime.\n"); AndroidRuntime* runtime = AndroidRuntime::getRuntime(); LOGI("System server: starting Android services.\n"); runtime->callStatic("com/android/server/SystemServer", "init2"); // If running in our own process, just go into the thread // pool. Otherwise, call the initialization finished // func to let this process continue its initilization. if (proc->supportsProcesses()) { LOGI("System server: entering thread pool.\n"); ProcessState::self()->startThreadPool(); IPCThreadState::self()->joinThreadPool(); LOGI("System server: exiting thread pool.\n"); } return NO_ERROR; } 这个函数首先会初始化SurfaceFlinger、SensorService、AudioFlinger、MediaPlayerService、CameraService和AudioPolicyService这几个服务,然后就通过系统全局唯一的AndroidRuntime实例变量runtime的callStatic来调用SystemServer的init2函数了。关于这个AndroidRuntime实例变量runtime的相关资料,可能参考前面一篇文章Android应用程序进程启动过程的源代码分析一文。 ## Step 4. AndroidRuntime.callStatic 这个函数定义在frameworks/base/core/jni/AndroidRuntime.cpp文件中: [cpp] view plain copy /* * Call a static Java Programming Language function that takes no arguments and returns void. */ status_t AndroidRuntime::callStatic(const char* className, const char* methodName) { JNIEnv* env; jclass clazz; jmethodID methodId; env = getJNIEnv(); if (env == NULL) return UNKNOWN_ERROR; clazz = findClass(env, className); if (clazz == NULL) { LOGE("ERROR: could not find class '%s'\n", className); return UNKNOWN_ERROR; } methodId = env->GetStaticMethodID(clazz, methodName, "()V"); if (methodId == NULL) { LOGE("ERROR: could not find method %s.%s\n", className, methodName); return UNKNOWN_ERROR; } env->CallStaticVoidMethod(clazz, methodId); return NO_ERROR; } 这个函数调用由参数className指定的java类的静态成员函数,这个静态成员函数是由参数methodName指定的。上面传进来的参数className的值为"com/android/server/SystemServer",而参数methodName的值为"init2",因此,接下来就会调用SystemServer类的init2函数了。 ##Step 5. SystemServer.init2 这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中: [java] view plain copy public class SystemServer { ...... public static final void init2() { Slog.i(TAG, "Entered the Android system server!"); Thread thr = new ServerThread(); thr.setName("android.server.ServerThread"); thr.start(); } } 这个函数创建了一个ServerThread线程,PackageManagerService服务就是这个线程中启动的了。这里调用了ServerThread实例thr的start函数之后,下面就会执行这个实例的run函数了。 ##Step 6. ServerThread.run 这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中: [java] view plain copy class ServerThread extends Thread { ...... @Override public void run() { ...... IPackageManager pm = null; ...... // Critical services... try { ...... Slog.i(TAG, "Package Manager"); pm = PackageManagerService.main(context, factoryTest != SystemServer.FACTORY_TEST_OFF); ...... } catch (RuntimeException e) { Slog.e("System", "Failure starting core service", e); } ...... } ...... } 这个函数除了启动PackageManagerService服务之外,还启动了其它很多的服务,例如在前面学习Activity和Service的几篇文章中经常看到的ActivityManagerService服务,有兴趣的读者可以自己研究一下。 ##Step 7. PackageManagerService.main 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中: [cpp] view plain copy class PackageManagerService extends IPackageManager.Stub { ...... public static final IPackageManager main(Context context, boolean factoryTest) { PackageManagerService m = new PackageManagerService(context, factoryTest); ServiceManager.addService("package", m); return m; } ...... }

    3.常见的4种安装场景

    1.系统应用安装――开机时完成,没有安装界面

    2.网络下载应用安装――通过market应用完成,没有安装界面

    3.ADB工具安装――没有安装界面。

    4.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。

    安装过程:

    复制APK安装包到data/app目录下,解压并扫描安装包,把dex文件(Dalvik字节码)保存到dalvik-cache目录,并data/data目录下创建对应的应用数据目录。

    卸载过程:

    删除安装过程中在上述三个目录下创建的文件及目录。

    (1)系统应用安装――开机时完成,没有安装界面

    PackageManagerService处理各种应用的安装,卸载,管理等工作,开机时由systemServer启动此服务

    在创建这个PackageManagerService服务实例时,会在PackageManagerService类的构造函数中开始执行安装应用程序的过程:

    PackageManagerService核心代码

    [java] view plain copy class PackageManagerService extends IPackageManager.Stub { ...... public PackageManagerService(Context context, boolean factoryTest) { ...... mSetting = new Setting(); synchronized (mInstallLock) { synchronized (mPackages) { ...... File dataDir = Environment.getDataDirectory(); mAppDataDir = new File(dataDir, "data"); mSecureAppDataDir = new File(dataDir, "secure/data"); mRestoredSetting = mASetting.readLP(); mDrmAppPrivateInstallDir = new File(dataDir, "app-private"); ...... mFrameworkDir = new File(Environment.getRootDirectory(), "framework"); mDalvikCacheDir = new File(dataDir, "dalvik-cache"); ...... // Find base frameworks (resource packages without code). mFrameworkInstallObserver = new AppDirObserver( mFrameworkDir.getPath(), OBSERVER_EVENTS, true); mFrameworkInstallObserver.startWatching(); scanDirLI(mFrameworkDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode | SCAN_NO_DEX, 0); // Collect all system packages. mSystemAppDir = new File(Environment.getRootDirectory(), "app"); mSystemInstallObserver = new AppDirObserver( mSystemAppDir.getPath(), OBSERVER_EVENTS, true); mSystemInstallObserver.startWatching(); scanDirLI(mSystemAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); // Collect all vendor packages. mVendorAppDir = new File("/vendor/app"); mVendorInstallObserver = new AppDirObserver( mVendorAppDir.getPath(), OBSERVER_EVENTS, true); mVendorInstallObserver.startWatching(); scanDirLI(mVendorAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); mAppInstallObserver = new AppDirObserver( mAppInstallDir.getPath(), OBSERVER_EVENTS, false); mAppInstallObserver.startWatching(); scanDirLI(mAppInstallDir, 0, scanMode, 0); mDrmAppInstallObserver = new AppDirObserver( mDrmAppPrivateInstallDir.getPath(), OBSERVER_EVENTS, false); mDrmAppInstallObserver.startWatching(); scanDirLI(mDrmAppPrivateInstallDir, PackageParser.PARSE_FORWARD_LOCK, scanMode, 0); ...... final boolean regrantPermissions = mSetting.mInternalSDKplatform != mSdkVersion; updatePermissionsLP(null,null,true,rregrantPermissions .regrantPermissions ); msetting.writeLP(); } } } ...... } #这里会调用scanDirLI函数来扫描移动设备上的下面这五个目录中的Apk文件 /system/framework /system/app /vendor/app /data/app /data/app-private 由于Android每次启动的时候都需要安装一次信息,但是有些信息是保持不变的,例如Linux用户组Id,PackageManagerService 每次安装程序之后,都会把这些程序的信息保存下来,以便下次使用,

    恢复上一次程序的安装信息是通过PackageManagerService 的成员变量mSetting的readLP()来实现的,恢复信息之后就开始扫描和安装app了。

    #扫描安装app ##Step 8. PackageManagerService.scanDirLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中: [java] view plain copy class PackageManagerService extends IPackageManager.Stub { ...... private void scanDirLI(File dir, int flags, int scanMode, long currentTime) { String[] files = dir.list(); ...... int i; for (i=0; i<files.length; i++) { File file = new File(dir, files[i]); if (!isPackageFilename(files[i])) { // Ignore entries which are not apk's continue; } PackageParser.Package pkg = scanPackageLI(file, flags|PackageParser.PARSE_MUST_BE_APK, scanMode, currentTime); // Don't mess around with apps in system partition. if (pkg == null && (flags & PackageParser.PARSE_IS_SYSTEM) == 0 && mLastScanError == PackageManager.INSTALL_FAILED_INVALID_APK) { // Delete the apk Slog.w(TAG, "Cleaning up failed install of " + file); file.delete(); } } } ...... } 对于目录中的每一个文件,如果是以后Apk作为后缀名,那么就调用scanPackageLI函数来对它进行解析和安装。 ##Step 9. PackageManagerService.scanPackageLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中: [java] view plain copy 在CODE上查看代码片派生到我的代码片 class PackageManagerService extends IPackageManager.Stub { ...... private PackageParser.Package scanPackageLI(File scanFile, int parseFlags, int scanMode, long currentTime) { ...... String scanPath = scanFile.getPath(); parseFlags |= mDefParseFlags; PackageParser pp = new PackageParser(scanPath); ...... final PackageParser.Package pkg = pp.parsePackage(scanFile, scanPath, mMetrics, parseFlags); ...... return scanPackageLI(pkg, parseFlags, scanMode | SCAN_UPDATE_SIGNATURE, currentTime); } ...... } 这个函数首先会为这个Apk文件创建一个PackageParser实例,接着调用这个实例的parsePackage函数来对这个Apk文件进行解析。这个函数最后还会调用另外一个版本的scanPackageLI函数把来解析后得到的应用程序信息保存在PackageManagerService中。 ## Step 10. PackageParser.parsePackage 这个函数定义在frameworks/base/core/java/android/content/pm/PackageParser.java文件中: [java] view plain copy 在CODE上查看代码片派生到我的代码片 public class PackageParser { ...... public Package parsePackage(File sourceFile, String destCodePath, DisplayMetrics metrics, int flags) { ...... mArchiveSourcePath = sourceFile.getPath(); ...... XmlResourceParser parser = null; AssetManager assmgr = null; boolean assetError = true; try { assmgr = new AssetManager(); int cookie = assmgr.addAssetPath(mArchiveSourcePath); if(cookie != 0) { parser = assmgr.openXmlResourceParser(cookie, "AndroidManifest.xml"); assetError = false; } else { ...... } } catch (Exception e) { ...... } ...... String[] errorText = new String[1]; Package pkg = null; Exception errorException = null; try { // XXXX todo: need to figure out correct configuration. Resources res = new Resources(assmgr, metrics, null); pkg = parsePackage(res, parser, flags, errorText); } catch (Exception e) { ...... } ...... parser.close(); assmgr.close(); // Set code and resource paths pkg.mPath = destCodePath; pkg.mScanPath = mArchiveSourcePath; //pkg.applicationInfo.sourceDir = destCodePath; //pkg.applicationInfo.publicSourceDir = destRes; pkg.mSignatures = null; return pkg; } ...... } 每一个Apk文件都是一个归档文件,它里面包含了Android应用程序的配置文件AndroidManifest.xml,这里主要就是要对这个配置文件就行解析了,从Apk归档文件中得到这个配置文件后,就调用另一外版本的parsePackage函数对这个应用程序进行解析了:

    [java] view plain copy 在CODE上查看代码片派生到我的代码片

    public class PackageParser { ...... private Package parsePackage( Resources res, XmlResourceParser parser, int flags, String[] outError) throws XmlPullParserException, IOException { ...... String pkgName = parsePackageName(parser, attrs, flags, outError); ...... final Package pkg = new Package(pkgName); ...... int type; ...... TypedArray sa = res.obtainAttributes(attrs, com.android.internal.R.styleable.AndroidManifest); ...... while ((type=parser.next()) != parser.END_DOCUMENT && (type != parser.END_TAG || parser.getDepth() > outerDepth)) { if (type == parser.END_TAG || type == parser.TEXT) { continue; } String tagName = parser.getName(); if (tagName.equals("application")) { ...... if (!parseApplication(pkg, res, parser, attrs, flags, outError)) { return null; } } else if (tagName.equals("permission-group")) { ...... } else if (tagName.equals("permission")) { ...... } else if (tagName.equals("permission-tree")) { ...... } else if (tagName.equals("uses-permission")) { ...... } else if (tagName.equals("uses-configuration")) { ...... } else if (tagName.equals("uses-feature")) { ...... } else if (tagName.equals("uses-sdk")) { ...... } else if (tagName.equals("supports-screens")) { ...... } else if (tagName.equals("protected-broadcast")) { ...... } else if (tagName.equals("instrumentation")) { ...... } else if (tagName.equals("original-package")) { ...... } else if (tagName.equals("adopt-permissions")) { ...... } else if (tagName.equals("uses-gl-texture")) { ...... } else if (tagName.equals("compatible-screens")) { ...... } else if (tagName.equals("eat-comment")) { ...... } else if (RIGID_PARSER) { ...... } else { ...... } } ...... return pkg; } ...... } 这里就是对AndroidManifest.xml文件中的各个标签进行解析了,各个标签的含义可以参考官方文档http://developer.android.com/guide/topics/manifest/manifest-intro.html,这里我们只简单看一下application标签的解析,这是通过调用parseApplication函数来进行的。 ## Step 11. PackageParser.parseApplication 这个函数定义在frameworks/base/core/java/android/content/pm/PackageParser.java文件中: [java] view plain copy 在CODE上查看代码片派生到我的代码片 public class PackageParser { ...... private boolean parseApplication(Package owner, Resources res, XmlPullParser parser, AttributeSet attrs, int flags, String[] outError) throws XmlPullParserException, IOException { final ApplicationInfo ai = owner.applicationInfo; final String pkgName = owner.applicationInfo.packageName; TypedArray sa = res.obtainAttributes(attrs, com.android.internal.R.styleable.AndroidManifestApplication); ...... int type; while ((type=parser.next()) != parser.END_DOCUMENT && (type != parser.END_TAG || parser.getDepth() > innerDepth)) { if (type == parser.END_TAG || type == parser.TEXT) { continue; } String tagName = parser.getName(); if (tagName.equals("activity")) { Activity a = parseActivity(owner, res, parser, attrs, flags, outError, false); ...... owner.activities.add(a); } else if (tagName.equals("receiver")) { Activity a = parseActivity(owner, res, parser, attrs, flags, outError, true); ...... owner.receivers.add(a); } else if (tagName.equals("service")) { Service s = parseService(owner, res, parser, attrs, flags, outError); ...... owner.services.add(s); } else if (tagName.equals("provider")) { Provider p = parseProvider(owner, res, parser, attrs, flags, outError); ...... owner.providers.add(p); } else if (tagName.equals("activity-alias")) { Activity a = parseActivityAlias(owner, res, parser, attrs, flags, outError); ...... owner.activities.add(a); } else if (parser.getName().equals("meta-data")) { ...... } else if (tagName.equals("uses-library")) { ...... } else if (tagName.equals("uses-package")) { ...... } else { ...... } } return true; } ...... } 这里就是对AndroidManifest.xml文件中的application标签进行解析了,我们常用到的标签就有activity、service、receiver和provider,各个标签的含义可以参考官方文档http://developer.android.com/guide/topics/manifest/manifest-intro.html。 这里解析完成后,一层层返回到Step 9中,调用另一个版本的scanPackageLI函数把来解析后得到的应用程序信息保存下来。 ##Step 12. PackageManagerService.scanPackageLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中: [java] view plain copy 在CODE上查看代码片派生到我的代码片 class PackageManagerService extends IPackageManager.Stub { ...... // Keys are String (package name), values are Package. This also serves // as the lock for the global state. Methods that must be called with // this lock held have the prefix "LP". final HashMap<String, PackageParser.Package> mPackages = new HashMap<String, PackageParser.Package>(); ...... // All available activities, for your resolving pleasure. final ActivityIntentResolver mActivities = new ActivityIntentResolver(); // All available receivers, for your resolving pleasure. final ActivityIntentResolver mReceivers = new ActivityIntentResolver(); // All available services, for your resolving pleasure. final ServiceIntentResolver mServices = new ServiceIntentResolver(); // Keys are String (provider class name), values are Provider. final HashMap<ComponentName, PackageParser.Provider> mProvidersByComponent = new HashMap<ComponentName, PackageParser.Provider>(); ...... private PackageParser.Package scanPackageLI(PackageParser.Package pkg, int parseFlags, int scanMode, long currentTime) { ...... synchronized (mPackages) { ...... // Add the new setting to mPackages mPackages.put(pkg.applicationInfo.packageName, pkg); ...... int N = pkg.providers.size(); int i; for (i=0; i<N; i++) { PackageParser.Provider p = pkg.providers.get(i); p.info.processName = fixProcessName(pkg.applicationInfo.processName, p.info.processName, pkg.applicationInfo.uid); mProvidersByComponent.put(new ComponentName(p.info.packageName, p.info.name), p); ...... } N = pkg.services.size(); for (i=0; i<N; i++) { PackageParser.Service s = pkg.services.get(i); s.info.processName = fixProcessName(pkg.applicationInfo.processName, s.info.processName, pkg.applicationInfo.uid); mServices.addService(s); ...... } N = pkg.receivers.size(); r = null; for (i=0; i<N; i++) { PackageParser.Activity a = pkg.receivers.get(i); a.info.processName = fixProcessName(pkg.applicationInfo.processName, a.info.processName, pkg.applicationInfo.uid); mReceivers.addActivity(a, "receiver"); ...... } N = pkg.activities.size(); for (i=0; i<N; i++) { PackageParser.Activity a = pkg.activities.get(i); a.info.processName = fixProcessName(pkg.applicationInfo.processName, a.info.processName, pkg.applicationInfo.uid); mActivities.addActivity(a, "activity"); ...... } ...... } ...... return pkg; } ...... }

    这个函数主要就是把前面解析应用程序得到的package、provider、service、receiver和activity等信息保存在PackageManagerService服务中了。

    PackageManagerService的作用总结:

    1)从apk, xml中载入pacakge信息, 存储到内部成员变量中, 用于后面的查找. 关键的方法是scanPackageLI(). 2)各种查询操作, 包括query Intent操作. 3)install package和delete package的操作. 还有后面的关键方法是installPackageLI().

    后面重点介绍installPackageLI,后面的额方式本质都会调用它。

    (2)从网络上下载应用:

    下载完成后,会自动调用Packagemanager的安装方法installPackage()

    “`

    /* Called when a downloaded package installation has been confirmed by the user */

    由英文注释可见PackageManagerService类的installPackage()函数为安装程序入口。

    [java] view plain copy public void installPackage( final Uri packageURI, final IPackageInstallObserver observer, final int flags, final String installerPackageName) { mContext.enforceCallingOrSelfPermission( android.Manifest.permission.INSTALL_PACKAGES, null); Message msg = mHandler.obtainMessage(INIT_COPY); msg.obj = new InstallParams(packageURI, observer, flags, installerPackageName); mHandler.sendMessage(msg); }

    其中是通过PackageHandler的实例mhandler.sendMessage(msg)把信息发给继承Handler的类HandleMessage()方法

    [java] view plain copy class PackageHandler extends Handler{

    *******省略若干********** public void handleMessage(Message msg) { try { doHandleMessage(msg); } finally { Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); } } ********省略若干************ }

    把信息发给doHandleMessage()方法,方法中用switch()语句进行判定传来Message

    [java] view plain copy void doHandleMessage(Message msg) { switch (msg.what) {

    case INIT_COPY: { if (DEBUG_SD_INSTALL) Log.i(TAG, "init_copy"); HandlerParams params = (HandlerParams) msg.obj; int idx = mPendingInstalls.size(); if (DEBUG_SD_INSTALL) Log.i(TAG, "idx=" + idx); // 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; } case MCS_BOUND: { if (DEBUG_SD_INSTALL) Log.i(TAG, "mcs_bound"); if (msg.obj != null) { mContainerService = (IMediaContainerService) msg.obj; } if (mContainerService == null) { // Something seriously wrong. Bail out Slog.e(TAG, "Cannot bind to media container service"); for (HandlerParams params : mPendingInstalls) { mPendingInstalls.remove(0); // Indicate service bind error params.serviceError(); } mPendingInstalls.clear(); } else if (mPendingInstalls.size() > 0) { HandlerParams params = mPendingInstalls.get(0); if (params != null) { params.startCopy(); } } else { // Should never happen ideally. Slog.w(TAG, "Empty queue"); } break; } ****************省略若干**********************

    } }

    public final boolean sendMessage (Message msg) public final boolean sendEmptyMessage (int what) 两者参数有别。 然后调用抽象类HandlerParams中的一个startCopy()方法 abstract class HandlerParams { final void startCopy() { ***************若干if语句判定否这打回handler消息******* handleReturnCode(); } } handleReturnCode()复写了两次其中有一次是删除时要调用的,只列出安装调用的一个方法

    [java] view plain copy @Override void handleReturnCode() { // If mArgs is null, then MCS couldn’t be reached. When it // reconnects, it will try again to install. At that point, this // will succeed. if (mArgs != null) { processPendingInstall(mArgs, mRet); } }

    这时可以清楚的看见 processPendingInstall()被调用。 其中run()方法如下 [java] view plain copy run(){ synchronized (mInstallLock) { ************省略***************** installPackageLI(args, true, res); } } instaPacakgeLI()args,res参数分析 ----------------------------------------------------------------------------------------- //InstallArgs 是在PackageService定义的static abstract class InstallArgs 静态抽象类。

    [java] view plain copy static abstract class InstallArgs {


    其中定义了flag标志,packageURL,创建文件,拷贝apk,修改包名称, 还有一些删除文件的清理,释放存储函数。 *********************************************************** } class PackageInstalledInfo { String name; int uid; PackageParser.Package pkg; int returnCode; PackageRemovedInfo removedInfo; }


    [java] view plain copy private void installPackageLI(InstallArgs args, boolean newInstall, PackageInstalledInfo res) { int pFlags = args.flags; String installerPackageName = args.installerPackageName; File tmpPackageFile = new File(args.getCodePath()); boolean forwardLocked = ((pFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0); boolean onSd = ((pFlags & PackageManager.INSTALL_EXTERNAL) != 0); boolean replace = false; int scanMode = (onSd ? 0 : SCAN_MONITOR) | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE | (newInstall ? SCAN_NEW_INSTALL : 0); // Result object to be returned res.returnCode = PackageManager.INSTALL_SUCCEEDED; // Retrieve PackageSettings and parse package int parseFlags = PackageParser.PARSE_CHATTY | (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0) | (onSd ? PackageParser.PARSE_ON_SDCARD : 0); parseFlags |= mDefParseFlags; PackageParser pp = new PackageParser(tmpPackageFile.getPath()); pp.setSeparateProcesses(mSeparateProcesses); final PackageParser.Package pkg = pp.parsePackage(tmpPackageFile, null, mMetrics, parseFlags); if (pkg == null) { res.returnCode = pp.getParseError(); return; } String pkgName = res.name = pkg.packageName; if ((pkg.applicationInfo.flags&ApplicationInfo.FLAG_TEST_ONLY) != 0) { if ((pFlags&PackageManager.INSTALL_ALLOW_TEST) == 0) { res.returnCode = PackageManager.INSTALL_FAILED_TEST_ONLY; return; } } if (GET_CERTIFICATES && !pp.collectCertificates(pkg, parseFlags)) { res.returnCode = pp.getParseError(); return; } // Get rid of all references to package scan path via parser. pp = null; String oldCodePath = null; boolean systemApp = false; synchronized (mPackages) { // Check if installing already existing package if ((pFlags&PackageManager.INSTALL_REPLACE_EXISTING) != 0) { String oldName = mSettings.mRenamedPackages.get(pkgName); if (pkg.mOriginalPackages != null && pkg.mOriginalPackages.contains(oldName) && mPackages.containsKey(oldName)) { // This package is derived from an original package, // and this device has been updating from that original // name. We must continue using the original name, so // rename the new package here. pkg.setPackageName(oldName); pkgName = pkg.packageName; replace = true; } else if (mPackages.containsKey(pkgName)) { // This package, under its official name, already exists // on the device; we should replace it. replace = true; } } PackageSetting ps = mSettings.mPackages.get(pkgName); if (ps != null) { oldCodePath = mSettings.mPackages.get(pkgName).codePathString; if (ps.pkg != null && ps.pkg.applicationInfo != null) { systemApp = (ps.pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0; } } } if (systemApp && onSd) { // Disable updates to system apps on sdcard Slog.w(TAG, “Cannot install updates to system apps on sdcard”); res.returnCode = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION; return; } if (!args.doRename(res.returnCode, pkgName, oldCodePath)) { res.returnCode = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE; return; } // Set application objects path explicitly after the rename setApplicationInfoPaths(pkg, args.getCodePath(), args.getResourcePath()); pkg.applicationInfo.nativeLibraryDir = args.getNativeLibraryPath(); if (replace) { replacePackageLI(pkg, parseFlags, scanMode, installerPackageName, res); } else { installNewPackageLI(pkg, parseFlags, scanMode, installerPackageName,res); } }

    最后判断如果以前不存在那么调用installNewPackageLI()

    [java] view plain copy private void installNewPackageLI(PackageParser.Package pkg, int parseFlags,int scanMode, String installerPackageName, PackageInstalledInfo res) { *************省略若干*************************************** PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags, scanMode, System.currentTimeMillis()); *************省略若干**************************************** }

    最后终于回到了和开机安装一样的地方.与开机方式安装调用统一方法。 #(3)从ADB工具安装 其入口函数源文件为pm.java (源文件路径:android\frameworks\base\cmds\pm\src\com\android\commands\pm\pm.java) 其中\system\framework\pm.jar 包管理库 包管理脚本 \system\bin\pm 解析 showUsage就是使用方法

    [java] view plain copy private static void showUsage() { System.err.println(“usage: pm [list|path|install|uninstall]”); System.err.println(” pm list packages [-f]”); System.err.println(” pm list permission-groups”); System.err.println(” pm list permissions [-g] [-f] [-d] [-u] [GROUP]”); System.err.println(” pm list instrumentation [-f] [TARGET-PACKAGE]”); System.err.println(” pm list features”); System.err.println(” pm path PACKAGE”); System.err.println(” pm install [-l] [-r] [-t] [-i INSTALLER_PACKAGE_NAME] [-s] [-f] PATH”); System.err.println(” pm uninstall [-k] PACKAGE”); System.err.println(” pm enable PACKAGE_OR_COMPONENT”); System.err.println(” pm disable PACKAGE_OR_COMPONENT”); System.err.println(” pm setInstallLocation [0/auto] [1/internal] [2/external]”); ************省略**************** }

    安装时候会调用 runInstall()方法

    [java] view plain copy private void runInstall() { int installFlags = 0; String installerPackageName = null; String opt; 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”); showUsage(); 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 { System.err.println(“Error: Unknown option: ” + opt); showUsage(); return; } } String apkFilePath = nextArg(); System.err.println(“\tpkg: ” + apkFilePath); if (apkFilePath == null) { System.err.println(“Error: no package specified”); showUsage(); return; } PackageInstallObserver obs = new PackageInstallObserver(); try { mPm.installPackage(Uri.fromFile(new File(apkFilePath)), obs, installFlags, installerPackageName); 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); } }

    其中的

    PackageInstallObserver obs = new PackageInstallObserver();

    mPm.installPackage(Uri.fromFile(new File(apkFilePath)), obs, installFlags, installerPackageName); 如果安装成功 obs.result == PackageManager.INSTALL_SUCCEEDED) 又因为有 IPackageManage mPm; mPm = IpackageManager.Stub.asInterface(ServiceManager.getService("package")); Stub是接口IPackageManage的静态抽象类,asInterface是返回IPackageManager代理的静态方法。 因为class PackageManagerService extends IPackageManager.Stub 所以mPm.installPackage 调用 /* Called when a downloaded package installation has been confirmed by the user */ public void installPackage( final Uri packageURI, final IPackageInstallObserver observer, final int flags,final String installerPackageName) 这样就是从网络下载安装的入口了。 #(4)从SD卡安装 系统调用PackageInstallerActivity.java(/home/zhongda/androidSRC/vortex-8inch-for-hoperun/packages/apps/PackageInstaller/src/com/android/packageinstaller) 进入这个Activity会判断信息是否有错,然后调用 private void initiateInstall()判断是否曾经有过同名包的安装,或者包已经安装 通过后执行private void startInstallConfirm() 点击OK按钮后经过一系列的安装信息的判断Intent跳转到

    [java] view plain copy public class InstallAppProgress extends Activity implements View.OnClickListener, OnCancelListener public void onCreate(Bundle icicle) { super.onCreate(icicle); Intent intent = getIntent(); mAppInfo = intent.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO); mPackageURI = intent.getData(); initView(); }

    方法中调用了initView()方法

    [java] view plain copy public void initView() { requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.op_progress); int installFlags = 0; PackageManager pm = getPackageManager(); try { PackageInfo pi = pm.getPackageInfo(mAppInfo.packageName, PackageManager.GET_UNINSTALLED_PACKAGES); if(pi != null) { installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; } } catch (NameNotFoundException e) { } if((installFlags & PackageManager.INSTALL_REPLACE_EXISTING )!= 0) { Log.w(TAG, “Replacing package:” + mAppInfo.packageName); } PackageUtil.AppSnippet as = PackageUtil.getAppSnippet(this, mAppInfo, mPackageURI); mLabel = as.label; PackageUtil.initSnippetForNewApp(this, as, R.id.app_snippet); mStatusTextView = (TextView)findViewById(R.id.center_text); mStatusTextView.setText(R.string.installing); mProgressBar = (ProgressBar) findViewById(R.id.progress_bar); mProgressBar.setIndeterminate(true); // Hide button till progress is being displayed mOkPanel = (View)findViewById(R.id.buttons_panel); mDoneButton = (Button)findViewById(R.id.done_button); mLaunchButton = (Button)findViewById(R.id.launch_button); mOkPanel.setVisibility(View.INVISIBLE); String installerPackageName = getIntent().getStringExtra( Intent.EXTRA_INSTALLER_PACKAGE_NAME); PackageInstallObserver observer = new PackageInstallObserver(); pm.installPackage(mPackageURI, observer, installFlags, installerPackageName); }

    “`

    方法最后我们可以看到再次调用安装接口完成安装。

    对于mSetting的介绍还不完善,后续会继续补充

    本文是读过下面的几篇博客和Android系统源代码情景分析之后写成的,感谢各位作者。

    参考:

    http://ticktick.blog.51cto.com/823160/1669525 http://blog.csdn.net/hdhd588/article/details/6739281 http://blog.csdn.net/luoshengyang/article/details/6766010 《Android系统源代码情景分析》

    转载请注明原文地址: https://ju.6miu.com/read-500071.html

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