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引言
Android系统服务启动顺序
zygote fork SystemServer 进程
SystemServer启动流程
1、SystemServer.main()
2、SystemServer.run()
3、初始化系统上下文
4、创建系统服务管理
5、启动系统各种服务
总结 引言
开机启动时 PowerManagerService 调用 AudioSer…目录
引言
Android系统服务启动顺序
zygote fork SystemServer 进程
SystemServer启动流程
1、SystemServer.main()
2、SystemServer.run()
3、初始化系统上下文
4、创建系统服务管理
5、启动系统各种服务
总结 引言
开机启动时 PowerManagerService 调用 AudioService 音频接口可能会导致 JE 崩溃进而 system_server 崩溃。
分析应该和系统服务SystemServer启动的顺序有关
Android系统服务启动顺序
Android整体启动流程概括为启动BootLoader-加载系统内核-启动Init进程-启动Zygote进程-启动Runtime进程-启动本地服务-启动Home Launcher SystemServer 服务进程是 Android 系统 Java 层框架的核心它维护着 Android 系统的 核心服务比如ActivityManagerService、WindowManagerService、PackageManagerService 等是 Android 系统中一个非常重要的进程。在 Android 系统中应用程序出现问题对系统影响不大而 Init、Zygote、SystemServer 三大进程对系统的影响则非常大因为其中任何一个 crash都会造成系统崩溃出现重启现象。
zygote fork SystemServer 进程
SystemServer 是由 Zygote 孵化而来的一个进程通过 ps 命令我们发现其进程名为system_server。在分析 zygote 进程时我们知道当 zygote 进程进入到 java 世界后在 ZygoteInit.java 中将调用 forkSystemServer 方法启动 SystemServer 进程。
// frameworks/base/core/java/com/android/internal/os/ZygoteInit.javapublic class ZygoteInit {public static void main(String argv[]) {try {if (startSystemServer) {// fork 出 system_serverRunnable r forkSystemServer(abiList, zygoteSocketName, zygoteServer);if (r ! null) {r.run();return;}}}}private static Runnable forkSystemServer(String abiList, String socketName,ZygoteServer zygoteServer) {try {... .../* Request to fork the system server process */pid Zygote.forkSystemServer(parsedArgs.mUid, parsedArgs.mGid,parsedArgs.mGids,parsedArgs.mRuntimeFlags,null,parsedArgs.mPermittedCapabilities,parsedArgs.mEffectiveCapabilities);} catch (IllegalArgumentException ex) {throw new RuntimeException(ex);}}}
......
SystemServer启动流程
1、SystemServer.main()
接下来就进到了 SystemServer.java 的 main() 函数处理流程
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {/*** The main entry point from zygote.*/public static void main(String[] args) {new SystemServer().run(); // 创建并运行简单粗暴}}
这里直接 new 出一个 SystemServer 对象 并执行其 run() 方法。
2、SystemServer.run()
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {private void run() {try {traceBeginAndSlog(InitBeforeStartServices);... ...// 如果系统时钟早于1970年则设置系统始终从1970年开始if (System.currentTimeMillis() EARLIEST_SUPPORTED_TIME) {Slog.w(TAG, System clock is before 1970; setting to 1970.);SystemClock.setCurrentTimeMillis(EARLIEST_SUPPORTED_TIME);}... ... if (!SystemProperties.get(persist.sys.language).isEmpty()) {// 设置区域语言等选项 final String languageTag Locale.getDefault().toLanguageTag();SystemProperties.set(persist.sys.locale, languageTag);SystemProperties.set(persist.sys.language, );SystemProperties.set(persist.sys.country, );SystemProperties.set(persist.sys.localevar, );}... ...// 清除 vm 内存增长上限由于启动过程需要较多的虚拟机内存空间VMRuntime.getRuntime().clearGrowthLimit(); // 设置堆栈利用率GC 后会重新计算堆栈空间大小VMRuntime.getRuntime().setTargetHeapUtilization(0.8f); // 针对部分设备依赖于运行时就产生指纹信息因此需要在开机完成前已经定义Build.ensureFingerprintProperty(); // 访问环境变量前需要明确地指定用户Environment.setUserRequired(true); ... ...// 加载动态库 libandroid_services.soSystem.loadLibrary(android_servers); // 检测上次关机过程是否失败该方法可能不会返回performPendingShutdown(); // 在 SystemServer 进程中也需要创建 Context 对象初始化系统上下文createSystemContext(); // 创建 SystemServiceManager 对象mSystemServiceManager new SystemServiceManager(mSystemContext); // SystemServer 进程主要是用来构建系统各种 service 服务// 而 SystemServiceManager 就是这些服务的管理对象 mSystemServiceManager.setStartInfo(mRuntimeRestart,mRuntimeStartElapsedTime, mRuntimeStartUptime); // 将 SystemServiceManager 对象保存到 SystemServer 进程中的一个数据结构中 LocalServices.addService(SystemServiceManager.class, mSystemServiceManager); // Prepare the thread pool for init tasks that can be parallelizedSystemServerInitThreadPool.get();} finally {traceEnd(); // InitBeforeStartServices}// Start services.try {traceBeginAndSlog(StartServices);startBootstrapServices(); // 主要用于启动系统 Boot 级服务 startCoreServices(); // 主要用于启动系统核心的服务 startOtherServices(); // 主要用于启动一些非紧要或者非需要及时启动的服务 } catch (Throwable ex) {Slog.e(System, ******************************************);Slog.e(System, ************ Failure starting system services, ex);throw ex;} finally {traceEnd();}... ...// 启动looper以处理到来的消息一直循环执行Looper.loop(); throw new RuntimeException(Main thread loop unexpectedly exited);}}
以上就是 SystemServer.run() 方法的整个流程简化如下
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {private void run() {try {// Initialize the system context.createSystemContext(); // 01. 初始化系统上下文// 02. 创建系统服务管理 mSystemServiceManager new SystemServiceManager(mSystemContext);mSystemServiceManager.setRuntimeRestarted(mRuntimeRestart); LocalServices.addService(SystemServiceManager.class, mSystemServiceManager); } finally {traceEnd(); // InitBeforeStartServices}// 03.启动系统各种服务try {startBootstrapServices(); // 启动引导服务startCoreServices(); // 启动核心服务startOtherServices(); // 启动其他服务}// Loop forever.Looper.loop(); // 一直循环执行 throw new RuntimeException(Main thread loop unexpectedly exited);}}
接下来我们针对 SystemServer 所做的 三部分工作 单独分析
3、初始化系统上下文
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {private void createSystemContext() {ActivityThread activityThread ActivityThread.systemMain();mSystemContext activityThread.getSystemContext();mSystemContext.setTheme(DEFAULT_SYSTEM_THEME);final Context systemUiContext activityThread.getSystemUiContext();systemUiContext.setTheme(DEFAULT_SYSTEM_THEME);}}
跟踪 systemMain() 方法
// frameworks/base/core/java/android/app/ActivityThread.javapublic final class ActivityThread extends ClientTransactionHandler {public static ActivityThread systemMain() {// The system process on low-memory devices do not get to use hardware// accelerated drawing, since this can add too much overhead to the// process.if (!ActivityManager.isHighEndGfx()) {ThreadedRenderer.disable(true); // 对于低内存的设备禁用硬件加速} else {ThreadedRenderer.enableForegroundTrimming();}ActivityThread thread new ActivityThread();thread.attach(true, 0); // 调用 attach() 方法return thread;}}
跟踪 attach() 方法
// frameworks/base/core/java/android/app/ActivityThread.javapublic final class ActivityThread extends ClientTransactionHandler {private void attach(boolean system, long startSeq) {sCurrentActivityThread this;mSystemThread system;if (!system) {... ...} else {// Dont set application object here -- if the system crashes,// we cant display an alert, we just want to die die die.// 设置 SystemServer 进程在 DDMS 中显示的名字为 system_processandroid.ddm.DdmHandleAppName.setAppName(system_process,UserHandle.myUserId()); // 如不设置则显示?无法调试该进程try {mInstrumentation new Instrumentation();mInstrumentation.basicInit(this);// 首先通过 getSystemContext() 创建系统上下文然后创建应用上下文ContextImpl context ContextImpl.createAppContext(this, getSystemContext().mPackageInfo);// 创建 ApplicationmInitialApplication context.mPackageInfo.makeApplication(true, null);// 调用 Application的 onCreate()mInitialApplication.onCreate();} catch (Exception e) {throw new RuntimeException(Unable to instantiate Application(): e.toString(), e);} }... ...ViewRootImpl.ConfigChangedCallback configChangedCallback (Configuration globalConfig) - {synchronized (mResourcesManager) {// We need to apply this change to the resources immediately, because upon returning// the view hierarchy will be informed about it.if (mResourcesManager.applyConfigurationToResourcesLocked(globalConfig,null /* compat */)) {updateLocaleListFromAppContext(mInitialApplication.getApplicationContext(),mResourcesManager.getConfiguration().getLocales());// This actually changed the resources! Tell everyone about it.if (mPendingConfiguration null|| mPendingConfiguration.isOtherSeqNewer(globalConfig)) {mPendingConfiguration globalConfig;sendMessage(H.CONFIGURATION_CHANGED, globalConfig);}}}};// 添加回调ViewRootImpl.addConfigCallback(configChangedCallback); }}
我们发现 attach() 方法主要做了四件事 1创建系统上下文getSystemContext() 2创建应用上下文createAppContext() 3创建 ApplicationmakeApplication() 4添加回调 configChangedCallback 到 ViewRootImpl。 1创建系统上下文
// frameworks/base/core/java/android/app/ActivityThread.javapublic final class ActivityThread extends ClientTransactionHandler {public ContextImpl getSystemContext() {synchronized (this) {if (mSystemContext null) {mSystemContext ContextImpl.createSystemContext(this);}return mSystemContext;}}}
// frameworks/base/core/java/android/app/ContextImpl.javaclass ContextImpl extends Context {static ContextImpl createSystemContext(ActivityThread mainThread) {// 这边 new 出来的 LoadedApk 将作为创建应用上下文的参数 packageInfoLoadedApk packageInfo new LoadedApk(mainThread);// ContextImpl() 创建系统上下文 ContextImpl context new ContextImpl(null, mainThread, packageInfo, null, null, null, 0,null, null);context.setResources(packageInfo.getResources());context.mResources.updateConfiguration(context.mResourcesManager.getConfiguration(),context.mResourcesManager.getDisplayMetrics());return context;}}
2创建应用上下文
// frameworks/base/core/java/android/app/ContextImpl.javaclass ContextImpl extends Context {static ContextImpl createAppContext(ActivityThread mainThread, LoadedApk packageInfo) {return createAppContext(mainThread, packageInfo, null);}static ContextImpl createAppContext(ActivityThread mainThread, LoadedApk packageInfo,String opPackageName) {if (packageInfo null) throw new IllegalArgumentException(packageInfo);// ContextImpl()创建应用上下文ContextImpl context new ContextImpl(null, mainThread, packageInfo, null, null, null, 0,null, opPackageName);context.setResources(packageInfo.getResources());return context;}}
我们可以看出new ContextImpl() 时系统上下文和应用上下文的参数是一样的createAppContext() 中的参数 packageInfo就是 createSystemContext() 中 new 的 LoadedApk。 创建完成之后系统上下文赋值给了 ActivityThread 的成员变量 mSystemContext而应用上下文只是作为函数中的局部变量临时使用。 3创建 Application
// frameworks/base/core/java/android/app/LoadedApk.javapublic final class LoadedApk {public Application makeApplication(boolean forceDefaultAppClass,Instrumentation instrumentation) {if (mApplication ! null) {return mApplication;}Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, makeApplication);Application app null;String appClass mApplicationInfo.className;if (forceDefaultAppClass || (appClass null)) { // forceDefaultAppClass 为 true appClass android.app.Application;}try {java.lang.ClassLoader cl getClassLoader();// 此 LoadedApk 对象是 createSystemContext 时 new 的mPackageName androidif (!mPackageName.equals(android)) { initializeJavaContextClassLoader();}// 又创建了一个局部应用上下文ContextImpl appContext ContextImpl.createAppContext(mActivityThread, this); // 创建 Application app mActivityThread.mInstrumentation.newApplication(cl, appClass, appContext);appContext.setOuterContext(app);} catch (Exception e) {if (!mActivityThread.mInstrumentation.onException(app, e)) {Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);throw new RuntimeException(Unable to instantiate application appClass : e.toString(), e);}}// 将前面创建的 app 添加到应用列表mActivityThread.mAllApplications.add(app);mApplication app;... ...Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);return app;}}
4、创建系统服务管理
回顾下创建系统服务管理相关代码
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {private void run() {try {// Initialize the system context.createSystemContext(); // 01. 初始化系统上下文// 02. 创建系统服务管理 mSystemServiceManager new SystemServiceManager(mSystemContext);mSystemServiceManager.setRuntimeRestarted(mRuntimeRestart); LocalServices.addService(SystemServiceManager.class, mSystemServiceManager); } finally {traceEnd(); // InitBeforeStartServices}... ...}
这一步只是 new 了一个 SystemServiceManager并将其添加到本地服务列表中。mSystemContext 为第一步中创建的系统上下文。本地服务列表是以类为 key 保存的一个列表即列表中某种类型的对象最多只能有一个。 new SystemServiceManager()
// frameworks/base/services/core/java/com/android/server/SystemServiceManager.javapublic class SystemServiceManager {... ...// 系统服务列表系统服务必须继承 SystemServiceprivate final ArrayListSystemService mServices new ArrayListSystemService();// 当前处于开机过程的哪个阶段private int mCurrentPhase -1;SystemServiceManager(Context context) {mContext context;}SuppressWarnings(unchecked)// 通过类名启动系统服务可能会找不到类而抛异常public SystemService startService(String className) {final ClassSystemService serviceClass;try {serviceClass (ClassSystemService)Class.forName(className);} catch (ClassNotFoundException ex) {Slog.i(TAG, Starting className);throw new RuntimeException(Failed to create service className : service class not found, usually indicates that the caller should have called PackageManager.hasSystemFeature() to check whether the feature is available on this device before trying to start the services that implement it, ex);}return startService(serviceClass);}SuppressWarnings(unchecked)// 创建并启动系统服务系统服务类必须继承 SystemServicepublic T extends SystemService T startService(ClassT serviceClass) {try {final String name serviceClass.getName();Slog.i(TAG, Starting name);Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, StartService name);// Create the service.if (!SystemService.class.isAssignableFrom(serviceClass)) {throw new RuntimeException(Failed to create name : service must extend SystemService.class.getName());}final T service;try {ConstructorT constructor serviceClass.getConstructor(Context.class);service constructor.newInstance(mContext);} catch (InstantiationException ex) {... ...}startService(service);return service;} finally {Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);}}public void startService(NonNull final SystemService service) {// Register it.mServices.add(service);// Start it.long time SystemClock.elapsedRealtime();try {service.onStart();} catch (RuntimeException ex) {throw new RuntimeException(Failed to start service service.getClass().getName() : onStart threw an exception, ex);}warnIfTooLong(SystemClock.elapsedRealtime() - time, service, onStart);}// 通知系统服务到了开机的哪个阶段会遍历调用所有系统服务的 onBootPhase() 函数public void startBootPhase(final int phase) {... ...try {Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, OnBootPhase phase);final int serviceLen mServices.size();for (int i 0; i serviceLen; i) {final SystemService service mServices.get(i);long time SystemClock.elapsedRealtime();Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, service.getClass().getName());try {service.onBootPhase(mCurrentPhase);} catch (Exception ex) {throw new RuntimeException(Failed to boot service service.getClass().getName() : onBootPhase threw an exception during phase mCurrentPhase, ex);}warnIfTooLong(SystemClock.elapsedRealtime() - time, service, onBootPhase);Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);}} finally {Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);}}}
5、启动系统各种服务
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {private void run() {// 01. 初始化系统上下文// 02. 创建系统服务管理 // 03.启动系统各种服务try {startBootstrapServices(); // 启动引导服务startCoreServices(); // 启动核心服务startOtherServices(); // 启动其他服务}// Loop forever.Looper.loop(); // 一直循环执行 throw new RuntimeException(Main thread loop unexpectedly exited);}}
1启动引导服务startBootstrapServices()
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {/*** Starts the small tangle of critical services that are needed to get the system off the* ground. These services have complex mutual dependencies which is why we initialize them all* in one place here. Unless your service is also entwined in these dependencies, it should be* initialized in one of the other functions.*/private void startBootstrapServices() {... ...// 启动 Installer 服务阻塞等待与 installd 建立 socket 通道Installer installer mSystemServiceManager.startService(Installer.class);mSystemServiceManager.startService(DeviceIdentifiersPolicyService.class);mSystemServiceManager.startService(UriGrantsManagerService.Lifecycle.class);// 启动 ActivityManagerServiceActivityTaskManagerService atm mSystemServiceManager.startService(ActivityTaskManagerService.Lifecycle.class).getService();mActivityManagerService.setSystemServiceManager(mSystemServiceManager);mActivityManagerService.setInstaller(installer);mWindowManagerGlobalLock atm.getGlobalLock();// 启动 PowerManagerServicemPowerManagerService mSystemServiceManager.startService(PowerManagerService.class);mSystemServiceManager.startService(ThermalManagerService.class);// PowerManagerService 就绪AMS 初始化电源管理mActivityManagerService.initPowerManagement();mActivityManagerService.initPowerManagement();mSystemServiceManager.startService(RecoverySystemService.class);RescueParty.noteBoot(mSystemContext);// 启动 LightsServicemSystemServiceManager.startService(LightsService.class);// 启动 DisplayManagerServicemDisplayManagerService mSystemServiceManager.startService(DisplayManagerService.class);// We need the default display before we can initialize the package manager.mSystemServiceManager.startBootPhase(SystemService.PHASE_WAIT_FOR_DEFAULT_DISPLAY);// 当设备正在加密时仅运行核心应用String cryptState SystemProperties.get(vold.decrypt);if (ENCRYPTING_STATE.equals(cryptState)) {Slog.w(TAG, Detected encryption in progress - only parsing core apps);mOnlyCore true;} else if (ENCRYPTED_STATE.equals(cryptState)) {Slog.w(TAG, Device encrypted - only parsing core apps);mOnlyCore true;}// Start the package manager.if (!mRuntimeRestart) {MetricsLogger.histogram(null, boot_package_manager_init_start,(int) SystemClock.elapsedRealtime());}// 启动 PackageManagerServicetry {Watchdog.getInstance().pauseWatchingCurrentThread(packagemanagermain);mPackageManagerService PackageManagerService.main(mSystemContext, installer,mFactoryTestMode ! FactoryTest.FACTORY_TEST_OFF, mOnlyCore);} finally {Watchdog.getInstance().resumeWatchingCurrentThread(packagemanagermain);}mFirstBoot mPackageManagerService.isFirstBoot();mPackageManager mSystemContext.getPackageManager();... ...// 将 UserManagerService 添加到服务列表该服务是在 PackageManagerService 中初始化的 mSystemServiceManager.startService(UserManagerService.LifeCycle.class);// 初始化用来缓存包资源的属性缓存AttributeCache.init(mSystemContext);// Set up the Application instance for the system process and get started.mActivityManagerService.setSystemProcess();... ...mSensorServiceStart SystemServerInitThreadPool.get().submit(() - {TimingsTraceLog traceLog new TimingsTraceLog(SYSTEM_SERVER_TIMING_ASYNC_TAG, Trace.TRACE_TAG_SYSTEM_SERVER);traceLog.traceBegin(START_SENSOR_SERVICE);startSensorService(); // 启动传感器服务traceLog.traceEnd();}, START_SENSOR_SERVICE);}}
首先等待 installd 启动完成然后启动一些相互依赖的关键服务。
2启动核心服务startCoreServices()
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {/*** Starts some essential services that are not tangled up in the bootstrap process.*/private void startCoreServices() {// 启动 BatteryService用于统计电池电量需要 LightServicemSystemServiceManager.startService(BatteryService.class);// 启动 UsageStatsService用于统计应用使用情况mSystemServiceManager.startService(UsageStatsService.class);mActivityManagerService.setUsageStatsManager(LocalServices.getService(UsageStatsManagerInternal.class));// 启动 WebViewUpdateServiceif (mPackageManager.hasSystemFeature(PackageManager.FEATURE_WEBVIEW)) {mWebViewUpdateService mSystemServiceManager.startService(WebViewUpdateService.class);}.... ...}}
3启动其他服务startOtherServices()
代码很长1200多行...但是逻辑简单主要是启动各种服务。
// frameworks/base/services/java/com/android/server/SystemServer.javapublic final class SystemServer {/*** Starts a miscellaneous grab bag of stuff that has yet to be refactored and organized.*/private void startOtherServices() {... ...try {... ...// 调度策略ServiceManager.addService(scheduling_policy, new SchedulingPolicyService());mSystemServiceManager.startService(TelecomLoaderService.class);// 提供电话注册、管理服务可以获取电话的链接状态、信号强度等telephonyRegistry new TelephonyRegistry(context);ServiceManager.addService(telephony.registry, telephonyRegistry);mEntropyMixer new EntropyMixer(context);mContentResolver context.getContentResolver();// 提供所有账号、密码、认证管理等等的服务mSystemServiceManager.startService(ACCOUNT_SERVICE_CLASS);... ...// 振动器服务vibrator new VibratorService(context);ServiceManager.addService(vibrator, vibrator);... ...inputManager new InputManagerService(context);// WMS needs sensor service readyConcurrentUtils.waitForFutureNoInterrupt(mSensorServiceStart, START_SENSOR_SERVICE);mSensorServiceStart null;wm WindowManagerService.main(context, inputManager, !mFirstBoot, mOnlyCore,new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated */ false,DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);ServiceManager.addService(Context.INPUT_SERVICE, inputManager,/* allowIsolated */ false, DUMP_FLAG_PRIORITY_CRITICAL);... ...} catch (RuntimeException e) {Slog.e(System, ******************************************);Slog.e(System, ************ Failure starting core service, e);}... ...LockSettingsService // 屏幕锁定服务管理每个用户的相关锁屏信息DeviceIdleController // Doze模式的主要驱动DevicePolicyManagerService // 提供一些系统级别的设置及属性StatusBarManagerService // 状态栏管理服务ClipboardService // 系统剪切板服务NetworkManagementService // 网络管理服务TextServicesManagerService // 文本服务例如文本检查等NetworkScoreService // 网络评分服务NetworkStatsService // 网络状态服务NetworkPolicyManagerService // 网络策略服务WifiP2pService // Wifi Direct服务WifiService // Wifi服务WifiScanningService // Wifi扫描服务RttService // Wifi相关EthernetService // 以太网服务ConnectivityService // 网络连接管理服务NsdService // 网络发现服务NotificationManagerService // 通知栏管理服务DeviceStorageMonitorService // 磁盘空间状态检测服务LocationManagerService // 位置服务GPS、定位等CountryDetectorService // 检测用户国家SearchManagerService // 搜索管理服务DropBoxManagerService // 用于系统运行时日志的存储于管理WallpaperManagerService // 壁纸管理服务AudioService // AudioFlinger的上层管理封装主要是音量、音效、声道及铃声等的管理DockObserver // 如果系统有个座子当手机装上或拔出这个座子的话就得靠他来管理了WiredAccessoryManager // 监视手机和底座上的耳机UsbService // USB服务SerialService // 串口服务TwilightService // 指出用户当前所在位置是否为晚上被 UiModeManager 等用来调整夜间模式BackupManagerService // 备份服务AppWidgetService // 提供Widget的管理和相关服务VoiceInteractionManagerService // 语音交互管理服务DiskStatsService // 磁盘统计服务供dumpsys使用SamplingProfilerService // 用于耗时统计等NetworkTimeUpdateService // 监视网络时间当网络时间变化时更新本地时间。CertBlacklister // 提供一种机制更新SSL certificate blacklistDreamManagerService // 屏幕保护PrintManagerService // 打印服务HdmiControlService // HDMI控制服务FingerprintService // 指纹服务... ...}}
总结 可以看到PowerManagerService先于AudioService启动此时如果在PowerManagerService启动后立刻调用AudioService中的接口就会引发 JE 崩溃进而导致system_server崩溃。
