浅析SystemServer进程

发表于

前引

  • 在android framework或者应用程序开发中所需要的主要API都是以系统服务的形式存在的，例如获取终端的当前位置，读取感应器的数值，拨打电话等，这些基本的功能在framework中都是以服务的形式存在的。

  • 在android系统中，服务是没有UI界面的，它作为一个后台进程，周期性地执行某些特定任务。在开发一些用于处理无需用户干预的数据的后台应用程序时，经常会使用这类android应用程序服务，例如通过网络对数据进行周期性的监控，或接收RSS反馈分析XML数据。在开发android程序时，引入适当的服务，从而开发出更灵活、更健康、更便捷的优秀程序来。

  • android服务的种类主要有两类，一类是系统服务，它们是由framework提供的；另一类是应用程序服务，它们是应用程序开发者继承并实现Service类后开发出来的。

    android服务分类

SystemServer系统服务概要

  • SystemServer服务进程是android系统Java层框架的核心，它维护这android的核心服务，比如AMS、WMS、PMS等，是android系统中一个非常重要的进程。

  • init进程、zygote进程和SystemServer进程都非常重要，因为其中任何一个系统死机都会重启。在android系统中，应用程序出现问题，对系统的影响不大，因为应用程序出现问题不会引起系统重启。

  • init进程、zygote进程和SystemServer进程三者有着密切的联系。

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    private static boolean startSystemServer(String abiList, String socketName)
            throws MethodAndArgsCaller, RuntimeException {
        long capabilities = posixCapabilitiesAsBits(
            OsConstants.CAP_IPC_LOCK,
            OsConstants.CAP_KILL,
            OsConstants.CAP_NET_ADMIN,
            OsConstants.CAP_NET_BIND_SERVICE,
            OsConstants.CAP_NET_BROADCAST,
            OsConstants.CAP_NET_RAW,
            OsConstants.CAP_SYS_MODULE,
            OsConstants.CAP_SYS_NICE,
            OsConstants.CAP_SYS_RESOURCE,
            OsConstants.CAP_SYS_TIME,
            OsConstants.CAP_SYS_TTY_CONFIG
        );
        if (!SystemProperties.getBoolean(PROPERTY_RUNNING_IN_CONTAINER, false)) {
            capabilities |= posixCapabilitiesAsBits(OsConstants.CAP_BLOCK_SUSPEND);
        }
        String args[] = {
            "--setuid=1000",
            "--setgid=1000",
            "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,1021,1032,3001,3002,3003,3006,3007,3009,3010",
            "--capabilities=" + capabilities + "," + capabilities,
            "--nice-name=system_server",
            "--runtime-args",
            "com.android.server.SystemServer",
        };
        ZygoteConnection.Arguments parsedArgs = null;
        int pid;
        try {
            parsedArgs = new ZygoteConnection.Arguments(args);
            ZygoteConnection.applyDebuggerSystemProperty(parsedArgs);
            ZygoteConnection.applyInvokeWithSystemProperty(parsedArgs);
            // 
            pid = Zygote.forkSystemServer(
                    parsedArgs.uid, parsedArgs.gid,
                    parsedArgs.gids,
                    parsedArgs.debugFlags,
                    null,
                    parsedArgs.permittedCapabilities,
                    parsedArgs.effectiveCapabilities);
        } catch (IllegalArgumentException ex) {
            throw new RuntimeException(ex);
        }
        if (pid == 0) {
            if (hasSecondZygote(abiList)) {
                waitForSecondaryZygote(socketName);
            }
            handleSystemServerProcess(parsedArgs);
        }
        return true;
    }

    SystemServer系统服务进程是由zygote进程启动的，从ZygoteInit类的startSystemServer()方法开始，在startSystemServer()方法中调用了两个方法，分别是zygote的forkSystemServer()方法和handleSystemServerProcess()方法，其中，handleSystemServerProcess()是子进程即SystemServer进程的方法，而forkSystemServer()方法是在父进程即zygote进程的方法，handleSystemServerProcess()在android启动过程分析——zygote进程已经分析过了，接下来就来分析forkSystemServer()这个方法。

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    public static int forkSystemServer(int uid, int gid, int[] gids, int debugFlags,
            int[][] rlimits, long permittedCapabilities, long effectiveCapabilities) {
        VM_HOOKS.preFork();
        int pid = nativeForkSystemServer(
                uid, gid, gids, debugFlags, rlimits, permittedCapabilities, effectiveCapabilities);
        if (pid == 0) {
            Trace.setTracingEnabled(true);
        }
        VM_HOOKS.postForkCommon();
        return pid;
    }

    forkSystemServer()方法调用了nativeForkSystemServer()方法来做进一步处理，它是一个native的方法。

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    static jint com_android_internal_os_Zygote_nativeForkSystemServer(
            JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids,
            jint debug_flags, jobjectArray rlimits, jlong permittedCapabilities,
            jlong effectiveCapabilities) {
      // 传入众多参数来fork一个新的进程
      pid_t pid = ForkAndSpecializeCommon(env, uid, gid, gids,
                                          debug_flags, rlimits,
                                          permittedCapabilities, effectiveCapabilities,
                                          MOUNT_EXTERNAL_DEFAULT, NULL, NULL, true, NULL,
                                          NULL, NULL);
      if (pid > 0) {
          ALOGI("System server process %d has been created", pid);
          gSystemServerPid = pid;
          int status;
          if (waitpid(pid, &status, WNOHANG) == pid) {
              ALOGE("System server process %d has died. Restarting Zygote!", pid);
              RuntimeAbort(env, __LINE__, "System server process has died. Restarting Zygote!");
          }
      }
      return pid;
    }

    在这个jni文件里的com_android_internal_os_Zygote_nativeForkSystemServer函数调用了ForkAndSpecializeCommon()函数来做进一步操作。

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    static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray javaGids,
                                         jint debug_flags, jobjectArray javaRlimits,
                                         jlong permittedCapabilities, jlong effectiveCapabilities,
                                         jint mount_external,
                                         jstring java_se_info, jstring java_se_name,
                                         bool is_system_server, jintArray fdsToClose,
                                         jstring instructionSet, jstring dataDir) {
      
      SetSigChldHandler();
      ....
      pid_t pid = fork();
      .......
      return pid;
    }

    ForkAndSpecializeCommon()函数调用了两个非常重要的函数，分别是SetSigChldHandler()函数和fork()函数，fork()函数用来创建一个新的子进程，SetSigChldHandler()函数设置了信号处理函数SigChldHandler。

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    static void SetSigChldHandler() {
      struct sigaction sa;
      memset(&sa, 0, sizeof(sa));
      // 当子进程死亡之后，就会产生一个信号，zygote进程收到这个信号之后就会调用SigChldHandler()函数处理。
      sa.sa_handler = SigChldHandler;
      int err = sigaction(SIGCHLD, &sa, NULL);
      if (err < 0) {
        ALOGW("Error setting SIGCHLD handler: %s", strerror(errno));
      }
    }

    接下来看看SigChldHandler()函数信号处理函数捕获异常的实现。

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    static void SigChldHandler(int /*signal_number*/) {
      pid_t pid;
      int status;
      int saved_errno = errno;
      while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
        if (WIFEXITED(status)) {
          if (WEXITSTATUS(status)) {
            ALOGI("Process %d exited cleanly (%d)", pid, WEXITSTATUS(status));
          }
        } else if (WIFSIGNALED(status)) {
          if (WTERMSIG(status) != SIGKILL) {
            ALOGI("Process %d exited due to signal (%d)", pid, WTERMSIG(status));
          }
          if (WCOREDUMP(status)) {
            ALOGI("Process %d dumped core.", pid);
          }
        }
        // gSystemServerPid表示SystemServer进程的pid，前面已经为它赋过值了。如果SystemServer进程停止工作，首先通过getpid()来获取zygote进程的pid,然后调用kill函数杀死它。即SystemServer停止工作后，zygote自杀，以达到zygote与SystemServer生死与共的目的
        if (pid == gSystemServerPid) {
          ALOGE("Exit zygote because system server (%d) has terminated", pid);
          kill(getpid(), SIGKILL);
        }
      }
      if (pid < 0 && errno != ECHILD) {
        ALOGW("Zygote SIGCHLD error in waitpid: %s", strerror(errno));
      }
      errno = saved_errno;
    }

    最后会看一下init进程的main()函数里的死循环，如果它的子进程zygote停止工作，就会去重启子进程。

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    int main(int argc, char** argv) {
      ...
        while (true) {
            if (!waiting_for_exec) {
            // 执行子进程对应的命令，即执行init.rc文件里配置的命令
            am.ExecuteOneCommand();
            // 这个函数用于重启死掉的service
            restart_processes();
            }
      ...
        }
      ...
    }

    从上面的过程可知，init进程、zygote进程、SystemServer进程紧密相连，任何一个都不能出问题。

SystemServer创建框架核心服务

  • SystemServer进程在android运行环境中扮演着“神经中枢”的作用，APK应用中能够直接交互的大部分系统服务都在该进程中运行，它创建了很多android系统核心服务，核心服务比如AMS、WMS、PMS等，这些系统服务都是以一个线程的方式存在于SystemServer进程中。

    SystemServer的服务

  • SystemServer进程由zygote进程创建，它是zygote进程的子进程，也是zygote的第一个子进程。当SystemServer启动后，就会进入main()方法，又在它的main()方法中调用run()方法。android系统的核心服务AMS、WMS、PMS等都是在run()方法中进行创建和初始化，当它们创建之后，会通过ServiceManager的add_service()方法把它们加入到ServiceManager中统一管理。

  • SystemServer创建服务的大致流程如下：

    SystemServer启动核心服务

  • 创建系统核心服务过程

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    public final class SystemServer {
        ...
    	public static void main(String[] args) {
            new SystemServer().run();
        }
      
        public SystemServer() {
            mFactoryTestMode = FactoryTest.getMode();
        }
      
        private void run() {
            try {
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "InitBeforeStartServices");
                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()) {
                    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", "");
                }
                Slog.i(TAG, "Entered the Android system server!");
                EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_SYSTEM_RUN, SystemClock.uptimeMillis());
              
                SystemProperties.set("persist.sys.dalvik.vm.lib.2", VMRuntime.getRuntime().vmLibrary());
                if (SamplingProfilerIntegration.isEnabled()) {
                    SamplingProfilerIntegration.start();
                    mProfilerSnapshotTimer = new Timer();
                    mProfilerSnapshotTimer.schedule(new TimerTask() {
                            @Override
                            public void run() {
                                SamplingProfilerIntegration.writeSnapshot("system_server", null);
                            }
                        }, SNAPSHOT_INTERVAL, SNAPSHOT_INTERVAL);
                }
                VMRuntime.getRuntime().clearGrowthLimit();
                VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);
                Build.ensureFingerprintProperty();
                Environment.setUserRequired(true);
                BaseBundle.setShouldDefuse(true);
                BinderInternal.disableBackgroundScheduling(true);
                BinderInternal.setMaxThreads(sMaxBinderThreads);
                // 设置SystemServer进程线程的优先级，这个优先级非常高
                android.os.Process.setThreadPriority(
                    android.os.Process.THREAD_PRIORITY_FOREGROUND);
                android.os.Process.setCanSelfBackground(false);
                // 创建消息队列
                Looper.prepareMainLooper();
                // 加载SystemServer需要的android_servers库
                System.loadLibrary("android_servers");
                performPendingShutdown();
                // 创建系统Context
                createSystemContext();
                mSystemServiceManager = new SystemServiceManager(mSystemContext);
                LocalServices.addService(SystemServiceManager.class, mSystemServiceManager);
            } finally {
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            try {
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartServices");
                // 接下来这三个方法是创建系统核心服务的实现
                startBootstrapServices();
                startCoreServices();
                startOtherServices();
            } catch (Throwable ex) {
                Slog.e("System", "******************************************");
                Slog.e("System", "************ Failure starting system services", ex);
                throw ex;
            } finally {
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
          
            if (StrictMode.conditionallyEnableDebugLogging()) {
                Slog.i(TAG, "Enabled StrictMode for system server main thread.");
            }
            // 进入消息循环
            Looper.loop();
            throw new RuntimeException("Main thread loop unexpectedly exited");
        }
      
      ...
    }

    run()方法调用了三个非常重要的方法来创建和启动核心服务，分别是startBootstrapServices()，startCoreServices()， startOtherServices()。 

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    private void startBootstrapServices() {
        // installer链接installd，请求installd安装apk
        Installer installer = mSystemServiceManager.startService(Installer.class);
        // 启动ActivityManagerService服务
        mActivityManagerService = mSystemServiceManager.startService(
                ActivityManagerService.Lifecycle.class).getService();
        mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
        mActivityManagerService.setInstaller(installer);
        // 启动电源管理服务
        mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "InitPowerManagement");
        mActivityManagerService.initPowerManagement();
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        mSystemServiceManager.startService(LightsService.class);
        mDisplayManagerService = mSystemServiceManager.startService(DisplayManagerService.class);
        mSystemServiceManager.startBootPhase(SystemService.PHASE_WAIT_FOR_DEFAULT_DISPLAY);
        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;
        }
        traceBeginAndSlog("StartPackageManagerService");
        // 启动PackageManagerService服务，用来安装apk,分配权限
        mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
                mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF, mOnlyCore);
        mFirstBoot = mPackageManagerService.isFirstBoot();
        mPackageManager = mSystemContext.getPackageManager();
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        if (!mOnlyCore) {
            boolean disableOtaDexopt = SystemProperties.getBoolean("config.disable_otadexopt",
                    false);
            if (!disableOtaDexopt) {
                traceBeginAndSlog("StartOtaDexOptService");
                try {
                    OtaDexoptService.main(mSystemContext, mPackageManagerService);
                } catch (Throwable e) {
                    reportWtf("starting OtaDexOptService", e);
                } finally {
                    Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                }
            }
        }
        traceBeginAndSlog("StartUserManagerService");
        mSystemServiceManager.startService(UserManagerService.LifeCycle.class);
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        AttributeCache.init(mSystemContext);
        mActivityManagerService.setSystemProcess();
        startSensorService();
    }

    startBootstrapServices()用来启动一些critical服务，这些服务有着复杂的互相依赖关系，所以把它们放在一个地方初始化。

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    private void startCoreServices() {
        mSystemServiceManager.startService(BatteryService.class);
        mSystemServiceManager.startService(UsageStatsService.class);
        mActivityManagerService.setUsageStatsManager(
                LocalServices.getService(UsageStatsManagerInternal.class));
        mWebViewUpdateService = mSystemServiceManager.startService(WebViewUpdateService.class);
    }

    startCoreServices()启动的是一些重要服务，如BatteryService，UsageStatsService等。

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    private void startOtherServices() {
        final Context context = mSystemContext;
        VibratorService vibrator = null;
        IMountService mountService = null;
        NetworkManagementService networkManagement = null;
        NetworkStatsService networkStats = null;
        NetworkPolicyManagerService networkPolicy = null;
        ConnectivityService connectivity = null;
        NetworkScoreService networkScore = null;
        NsdService serviceDiscovery= null;
        WindowManagerService wm = null;
        SerialService serial = null;
        NetworkTimeUpdateService networkTimeUpdater = null;
        CommonTimeManagementService commonTimeMgmtService = null;
        InputManagerService inputManager = null;
        TelephonyRegistry telephonyRegistry = null;
        ConsumerIrService consumerIr = null;
        MmsServiceBroker mmsService = null;
        HardwarePropertiesManagerService hardwarePropertiesService = null;
        boolean disableStorage = SystemProperties.getBoolean("config.disable_storage", false);
        boolean disableBluetooth = SystemProperties.getBoolean("config.disable_bluetooth", false);
        boolean disableLocation = SystemProperties.getBoolean("config.disable_location", false);
        boolean disableSystemUI = SystemProperties.getBoolean("config.disable_systemui", false);
        boolean disableNonCoreServices = SystemProperties.getBoolean("config.disable_noncore", false);
        boolean disableNetwork = SystemProperties.getBoolean("config.disable_network", false);
        boolean disableNetworkTime = SystemProperties.getBoolean("config.disable_networktime", false);
        boolean disableRtt = SystemProperties.getBoolean("config.disable_rtt", false);
        boolean disableMediaProjection = SystemProperties.getBoolean("config.disable_mediaproj",
                false);
        boolean disableSerial = SystemProperties.getBoolean("config.disable_serial", false);
        boolean disableSearchManager = SystemProperties.getBoolean("config.disable_searchmanager",
                false);
        boolean disableTrustManager = SystemProperties.getBoolean("config.disable_trustmanager",
                false);
        boolean disableTextServices = SystemProperties.getBoolean("config.disable_textservices", false);
        boolean disableSamplingProfiler = SystemProperties.getBoolean("config.disable_samplingprof",
                false);
        boolean isEmulator = SystemProperties.get("ro.kernel.qemu").equals("1");
        try {
            Slog.i(TAG, "Reading configuration...");
            SystemConfig.getInstance();
            traceBeginAndSlog("StartSchedulingPolicyService");
            ServiceManager.addService("scheduling_policy", new SchedulingPolicyService());
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            mSystemServiceManager.startService(TelecomLoaderService.class);
            traceBeginAndSlog("StartTelephonyRegistry");
            telephonyRegistry = new TelephonyRegistry(context);
            ServiceManager.addService("telephony.registry", telephonyRegistry);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartEntropyMixer");
            mEntropyMixer = new EntropyMixer(context);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            mContentResolver = context.getContentResolver();
            Slog.i(TAG, "Camera Service");
            mSystemServiceManager.startService(CameraService.class);
            traceBeginAndSlog("StartAccountManagerService");
            mSystemServiceManager.startService(ACCOUNT_SERVICE_CLASS);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartContentService");
            mSystemServiceManager.startService(CONTENT_SERVICE_CLASS);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("InstallSystemProviders");
            mActivityManagerService.installSystemProviders();
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartVibratorService");
            vibrator = new VibratorService(context);
            ServiceManager.addService("vibrator", vibrator);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartConsumerIrService");
            consumerIr = new ConsumerIrService(context);
            ServiceManager.addService(Context.CONSUMER_IR_SERVICE, consumerIr);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartAlarmManagerService");
            mSystemServiceManager.startService(AlarmManagerService.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("InitWatchdog");
            final Watchdog watchdog = Watchdog.getInstance();
            watchdog.init(context, mActivityManagerService);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartInputManagerService");
            inputManager = new InputManagerService(context);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartWindowManagerService");
            wm = WindowManagerService.main(context, inputManager,
                    mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
                    !mFirstBoot, mOnlyCore);
            ServiceManager.addService(Context.WINDOW_SERVICE, wm);
            ServiceManager.addService(Context.INPUT_SERVICE, inputManager);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("StartVrManagerService");
            mSystemServiceManager.startService(VrManagerService.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            mActivityManagerService.setWindowManager(wm);
            inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
            inputManager.start();
            mDisplayManagerService.windowManagerAndInputReady();
          
            if (isEmulator) {
                Slog.i(TAG, "No Bluetooth Service (emulator)");
            } else if (mFactoryTestMode == FactoryTest.FACTORY_TEST_LOW_LEVEL) {
                Slog.i(TAG, "No Bluetooth Service (factory test)");
            } else if (!context.getPackageManager().hasSystemFeature
                       (PackageManager.FEATURE_BLUETOOTH)) {
                Slog.i(TAG, "No Bluetooth Service (Bluetooth Hardware Not Present)");
            } else if (disableBluetooth) {
                Slog.i(TAG, "Bluetooth Service disabled by config");
            } else {
                mSystemServiceManager.startService(BluetoothService.class);
            }
            traceBeginAndSlog("ConnectivityMetricsLoggerService");
            mSystemServiceManager.startService(MetricsLoggerService.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            traceBeginAndSlog("PinnerService");
            mSystemServiceManager.startService(PinnerService.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        } catch (RuntimeException e) {
            Slog.e("System", "******************************************");
            Slog.e("System", "************ Failure starting core service", e);
        }
        StatusBarManagerService statusBar = null;
        INotificationManager notification = null;
        LocationManagerService location = null;
        CountryDetectorService countryDetector = null;
        ILockSettings lockSettings = null;
        AssetAtlasService atlas = null;
        MediaRouterService mediaRouter = null;
      
        if (mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
            mSystemServiceManager.startService(InputMethodManagerService.Lifecycle.class);
            traceBeginAndSlog("StartAccessibilityManagerService");
            try {
                ServiceManager.addService(Context.ACCESSIBILITY_SERVICE,
                        new AccessibilityManagerService(context));
            } catch (Throwable e) {
                reportWtf("starting Accessibility Manager", e);
            }
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        }
        try {
            wm.displayReady();
        } catch (Throwable e) {
            reportWtf("making display ready", e);
        }
        if (mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
            if (!disableStorage &&
                !"0".equals(SystemProperties.get("system_init.startmountservice"))) {
                try {
                    mSystemServiceManager.startService(MOUNT_SERVICE_CLASS);
                    mountService = IMountService.Stub.asInterface(
                            ServiceManager.getService("mount"));
                } catch (Throwable e) {
                    reportWtf("starting Mount Service", e);
                }
            }
        }
      
        mSystemServiceManager.startService(UiModeManagerService.class);
        if (!mOnlyCore) {
            Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "UpdatePackagesIfNeeded");
            try {
                mPackageManagerService.updatePackagesIfNeeded();
            } catch (Throwable e) {
                reportWtf("update packages", e);
            }
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        }
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "PerformFstrimIfNeeded");
        try {
            mPackageManagerService.performFstrimIfNeeded();
        } catch (Throwable e) {
            reportWtf("performing fstrim", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        try {
            ActivityManagerNative.getDefault().showBootMessage(
                    context.getResources().getText(
                            com.android.internal.R.string.android_upgrading_starting_apps),
                    false);
        } catch (RemoteException e) {
        }
        if (mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
            if (!disableNonCoreServices) {
                traceBeginAndSlog("StartLockSettingsService");
                try {
                    mSystemServiceManager.startService(LOCK_SETTINGS_SERVICE_CLASS);
                    lockSettings = ILockSettings.Stub.asInterface(
                            ServiceManager.getService("lock_settings"));
                } catch (Throwable e) {
                    reportWtf("starting LockSettingsService service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                if (!SystemProperties.get(PERSISTENT_DATA_BLOCK_PROP).equals("")) {
                    mSystemServiceManager.startService(PersistentDataBlockService.class);
                }
                mSystemServiceManager.startService(DeviceIdleController.class);
                mSystemServiceManager.startService(DevicePolicyManagerService.Lifecycle.class);
            }
            if (!disableSystemUI) {
                traceBeginAndSlog("StartStatusBarManagerService");
                try {
                    statusBar = new StatusBarManagerService(context, wm);
                    ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);
                } catch (Throwable e) {
                    reportWtf("starting StatusBarManagerService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices) {
                traceBeginAndSlog("StartClipboardService");
                try {
                    ServiceManager.addService(Context.CLIPBOARD_SERVICE,
                            new ClipboardService(context));
                } catch (Throwable e) {
                    reportWtf("starting Clipboard Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNetwork) {
                traceBeginAndSlog("StartNetworkManagementService");
                try {
                    networkManagement = NetworkManagementService.create(context);
                    ServiceManager.addService(Context.NETWORKMANAGEMENT_SERVICE, networkManagement);
                } catch (Throwable e) {
                    reportWtf("starting NetworkManagement Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices && !disableTextServices) {
                mSystemServiceManager.startService(TextServicesManagerService.Lifecycle.class);
            }
            if (!disableNetwork) {
                traceBeginAndSlog("StartNetworkScoreService");
                try {
                    networkScore = new NetworkScoreService(context);
                    ServiceManager.addService(Context.NETWORK_SCORE_SERVICE, networkScore);
                } catch (Throwable e) {
                    reportWtf("starting Network Score Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                traceBeginAndSlog("StartNetworkStatsService");
                try {
                    networkStats = NetworkStatsService.create(context, networkManagement);
                    ServiceManager.addService(Context.NETWORK_STATS_SERVICE, networkStats);
                } catch (Throwable e) {
                    reportWtf("starting NetworkStats Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                traceBeginAndSlog("StartNetworkPolicyManagerService");
                try {
                    networkPolicy = new NetworkPolicyManagerService(
                            context, mActivityManagerService,
                            (IPowerManager)ServiceManager.getService(Context.POWER_SERVICE),
                            networkStats, networkManagement);
                    ServiceManager.addService(Context.NETWORK_POLICY_SERVICE, networkPolicy);
                } catch (Throwable e) {
                    reportWtf("starting NetworkPolicy Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_WIFI_NAN)) {
                    mSystemServiceManager.startService(WIFI_NAN_SERVICE_CLASS);
                } else {
                    Slog.i(TAG, "No Wi-Fi NAN Service (NAN support Not Present)");
                }
                mSystemServiceManager.startService(WIFI_P2P_SERVICE_CLASS);
                mSystemServiceManager.startService(WIFI_SERVICE_CLASS);
                mSystemServiceManager.startService(
                            "com.android.server.wifi.scanner.WifiScanningService");
                if (!disableRtt) {
                    mSystemServiceManager.startService("com.android.server.wifi.RttService");
                }
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_ETHERNET) ||
                    mPackageManager.hasSystemFeature(PackageManager.FEATURE_USB_HOST)) {
                    mSystemServiceManager.startService(ETHERNET_SERVICE_CLASS);
                }
                traceBeginAndSlog("StartConnectivityService");
                try {
                    connectivity = new ConnectivityService(
                            context, networkManagement, networkStats, networkPolicy);
                    ServiceManager.addService(Context.CONNECTIVITY_SERVICE, connectivity);
                    networkStats.bindConnectivityManager(connectivity);
                    networkPolicy.bindConnectivityManager(connectivity);
                } catch (Throwable e) {
                    reportWtf("starting Connectivity Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                traceBeginAndSlog("StartNsdService");
                try {
                    serviceDiscovery = NsdService.create(context);
                    ServiceManager.addService(
                            Context.NSD_SERVICE, serviceDiscovery);
                } catch (Throwable e) {
                    reportWtf("starting Service Discovery Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices) {
                traceBeginAndSlog("StartUpdateLockService");
                try {
                    ServiceManager.addService(Context.UPDATE_LOCK_SERVICE,
                            new UpdateLockService(context));
                } catch (Throwable e) {
                    reportWtf("starting UpdateLockService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices) {
                mSystemServiceManager.startService(RecoverySystemService.class);
            }
            if (mountService != null && !mOnlyCore) {
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "WaitForAsecScan");
                try {
                    mountService.waitForAsecScan();
                } catch (RemoteException ignored) {
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            mSystemServiceManager.startService(NotificationManagerService.class);
            notification = INotificationManager.Stub.asInterface(
                    ServiceManager.getService(Context.NOTIFICATION_SERVICE));
            networkPolicy.bindNotificationManager(notification);
            mSystemServiceManager.startService(DeviceStorageMonitorService.class);
            if (!disableLocation) {
                traceBeginAndSlog("StartLocationManagerService");
                try {
                    location = new LocationManagerService(context);
                    ServiceManager.addService(Context.LOCATION_SERVICE, location);
                } catch (Throwable e) {
                    reportWtf("starting Location Manager", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                traceBeginAndSlog("StartCountryDetectorService");
                try {
                    countryDetector = new CountryDetectorService(context);
                    ServiceManager.addService(Context.COUNTRY_DETECTOR, countryDetector);
                } catch (Throwable e) {
                    reportWtf("starting Country Detector", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices && !disableSearchManager) {
                traceBeginAndSlog("StartSearchManagerService");
                try {
                    mSystemServiceManager.startService(SEARCH_MANAGER_SERVICE_CLASS);
                } catch (Throwable e) {
                    reportWtf("starting Search Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            mSystemServiceManager.startService(DropBoxManagerService.class);
            if (!disableNonCoreServices && context.getResources().getBoolean(
                        R.bool.config_enableWallpaperService)) {
                traceBeginAndSlog("StartWallpaperManagerService");
                mSystemServiceManager.startService(WALLPAPER_SERVICE_CLASS);
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            traceBeginAndSlog("StartAudioService");
            mSystemServiceManager.startService(AudioService.Lifecycle.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            if (!disableNonCoreServices) {
                mSystemServiceManager.startService(DockObserver.class);
                if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_WATCH)) {
                    mSystemServiceManager.startService(THERMAL_OBSERVER_CLASS);
                }
            }
            traceBeginAndSlog("StartWiredAccessoryManager");
            try {
                inputManager.setWiredAccessoryCallbacks(
                        new WiredAccessoryManager(context, inputManager));
            } catch (Throwable e) {
                reportWtf("starting WiredAccessoryManager", e);
            }
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            if (!disableNonCoreServices) {
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_MIDI)) {
                    mSystemServiceManager.startService(MIDI_SERVICE_CLASS);
                }
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_USB_HOST)
                        || mPackageManager.hasSystemFeature(
                                PackageManager.FEATURE_USB_ACCESSORY)) {
                    Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartUsbService");
                    mSystemServiceManager.startService(USB_SERVICE_CLASS);
                    Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                }
                if (!disableSerial) {
                    traceBeginAndSlog("StartSerialService");
                    try {
                        serial = new SerialService(context);
                        ServiceManager.addService(Context.SERIAL_SERVICE, serial);
                    } catch (Throwable e) {
                        Slog.e(TAG, "Failure starting SerialService", e);
                    }
                    Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                }
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER,
                        "StartHardwarePropertiesManagerService");
                try {
                    hardwarePropertiesService = new HardwarePropertiesManagerService(context);
                    ServiceManager.addService(Context.HARDWARE_PROPERTIES_SERVICE,
                            hardwarePropertiesService);
                } catch (Throwable e) {
                    Slog.e(TAG, "Failure starting HardwarePropertiesManagerService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            mSystemServiceManager.startService(TwilightService.class);
            mSystemServiceManager.startService(JobSchedulerService.class);
            mSystemServiceManager.startService(SoundTriggerService.class);
            if (!disableNonCoreServices) {
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_BACKUP)) {
                    mSystemServiceManager.startService(BACKUP_MANAGER_SERVICE_CLASS);
                }
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_APP_WIDGETS)
                    || context.getResources().getBoolean(R.bool.config_enableAppWidgetService)) {
                    mSystemServiceManager.startService(APPWIDGET_SERVICE_CLASS);
                }
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_VOICE_RECOGNIZERS)) {
                    mSystemServiceManager.startService(VOICE_RECOGNITION_MANAGER_SERVICE_CLASS);
                }
                if (GestureLauncherService.isGestureLauncherEnabled(context.getResources())) {
                    Slog.i(TAG, "Gesture Launcher Service");
                    mSystemServiceManager.startService(GestureLauncherService.class);
                }
                mSystemServiceManager.startService(SensorNotificationService.class);
                mSystemServiceManager.startService(ContextHubSystemService.class);
            }
            traceBeginAndSlog("StartDiskStatsService");
            try {
                ServiceManager.addService("diskstats", new DiskStatsService(context));
            } catch (Throwable e) {
                reportWtf("starting DiskStats Service", e);
            }
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            if (!disableSamplingProfiler) {
                traceBeginAndSlog("StartSamplingProfilerService");
                try {
                    ServiceManager.addService("samplingprofiler",
                                new SamplingProfilerService(context));
                } catch (Throwable e) {
                    reportWtf("starting SamplingProfiler Service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNetwork && !disableNetworkTime) {
                traceBeginAndSlog("StartNetworkTimeUpdateService");
                try {
                    networkTimeUpdater = new NetworkTimeUpdateService(context);
                    ServiceManager.addService("network_time_update_service", networkTimeUpdater);
                } catch (Throwable e) {
                    reportWtf("starting NetworkTimeUpdate service", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            traceBeginAndSlog("StartCommonTimeManagementService");
            try {
                commonTimeMgmtService = new CommonTimeManagementService(context);
                ServiceManager.addService("commontime_management", commonTimeMgmtService);
            } catch (Throwable e) {
                reportWtf("starting CommonTimeManagementService service", e);
            }
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            if (!disableNetwork) {
                traceBeginAndSlog("CertBlacklister");
                try {
                    CertBlacklister blacklister = new CertBlacklister(context);
                } catch (Throwable e) {
                    reportWtf("starting CertBlacklister", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices) {
                mSystemServiceManager.startService(DreamManagerService.class);
            }
            if (!disableNonCoreServices && ZygoteInit.PRELOAD_RESOURCES) {
                traceBeginAndSlog("StartAssetAtlasService");
                try {
                    atlas = new AssetAtlasService(context);
                    ServiceManager.addService(AssetAtlasService.ASSET_ATLAS_SERVICE, atlas);
                } catch (Throwable e) {
                    reportWtf("starting AssetAtlasService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            if (!disableNonCoreServices) {
                ServiceManager.addService(GraphicsStatsService.GRAPHICS_STATS_SERVICE,
                        new GraphicsStatsService(context));
            }
            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_PRINTING)) {
                mSystemServiceManager.startService(PRINT_MANAGER_SERVICE_CLASS);
            }
            mSystemServiceManager.startService(RestrictionsManagerService.class);
            mSystemServiceManager.startService(MediaSessionService.class);
            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_HDMI_CEC)) {
                mSystemServiceManager.startService(HdmiControlService.class);
            }
            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_LIVE_TV)) {
                mSystemServiceManager.startService(TvInputManagerService.class);
            }
            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_PICTURE_IN_PICTURE)) {
                mSystemServiceManager.startService(MediaResourceMonitorService.class);
            }
            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_LEANBACK)) {
                mSystemServiceManager.startService(TvRemoteService.class);
            }
            if (!disableNonCoreServices) {
                traceBeginAndSlog("StartMediaRouterService");
                try {
                    mediaRouter = new MediaRouterService(context);
                    ServiceManager.addService(Context.MEDIA_ROUTER_SERVICE, mediaRouter);
                } catch (Throwable e) {
                    reportWtf("starting MediaRouterService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                if (!disableTrustManager) {
                    mSystemServiceManager.startService(TrustManagerService.class);
                }
                if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_FINGERPRINT)) {
                    mSystemServiceManager.startService(FingerprintService.class);
                }
                traceBeginAndSlog("StartBackgroundDexOptService");
                try {
                    BackgroundDexOptService.schedule(context);
                } catch (Throwable e) {
                    reportWtf("starting BackgroundDexOptService", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
            mSystemServiceManager.startService(ShortcutService.Lifecycle.class);
            mSystemServiceManager.startService(LauncherAppsService.class);
        }
        if (!disableNonCoreServices && !disableMediaProjection) {
            mSystemServiceManager.startService(MediaProjectionManagerService.class);
        }
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_WATCH)) {
            mSystemServiceManager.startService(WEAR_BLUETOOTH_SERVICE_CLASS);
        }
        final boolean safeMode = wm.detectSafeMode();
        if (safeMode) {
            mActivityManagerService.enterSafeMode();
            VMRuntime.getRuntime().disableJitCompilation();
        } else {
            VMRuntime.getRuntime().startJitCompilation();
        }
        mmsService = mSystemServiceManager.startService(MmsServiceBroker.class);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeVibratorServiceReady");
        try {
            vibrator.systemReady();
        } catch (Throwable e) {
            reportWtf("making Vibrator Service ready", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeLockSettingsServiceReady");
        if (lockSettings != null) {
            try {
                lockSettings.systemReady();
            } catch (Throwable e) {
                reportWtf("making Lock Settings Service ready", e);
            }
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        mSystemServiceManager.startBootPhase(SystemService.PHASE_LOCK_SETTINGS_READY);
        mSystemServiceManager.startBootPhase(SystemService.PHASE_SYSTEM_SERVICES_READY);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeWindowManagerServiceReady");
        try {
            wm.systemReady();
        } catch (Throwable e) {
            reportWtf("making Window Manager Service ready", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        if (safeMode) {
            mActivityManagerService.showSafeModeOverlay();
        }
        Configuration config = wm.computeNewConfiguration();
        DisplayMetrics metrics = new DisplayMetrics();
        WindowManager w = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        w.getDefaultDisplay().getMetrics(metrics);
        context.getResources().updateConfiguration(config, metrics);
        final Theme systemTheme = context.getTheme();
        if (systemTheme.getChangingConfigurations() != 0) {
            systemTheme.rebase();
        }
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakePowerManagerServiceReady");
        try {
            mPowerManagerService.systemReady(mActivityManagerService.getAppOpsService());
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        } catch (Throwable e) {
            reportWtf("making Power Manager Service ready", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakePackageManagerServiceReady");
        try {
            mPackageManagerService.systemReady();
        } catch (Throwable e) {
            reportWtf("making Package Manager Service ready", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeDisplayManagerServiceReady");
        try {
            mDisplayManagerService.systemReady(safeMode, mOnlyCore);
        } catch (Throwable e) {
            reportWtf("making Display Manager Service ready", e);
        }
        Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        final NetworkManagementService networkManagementF = networkManagement;
        final NetworkStatsService networkStatsF = networkStats;
        final NetworkPolicyManagerService networkPolicyF = networkPolicy;
        final ConnectivityService connectivityF = connectivity;
        final NetworkScoreService networkScoreF = networkScore;
        final LocationManagerService locationF = location;
        final CountryDetectorService countryDetectorF = countryDetector;
        final NetworkTimeUpdateService networkTimeUpdaterF = networkTimeUpdater;
        final CommonTimeManagementService commonTimeMgmtServiceF = commonTimeMgmtService;
        final AssetAtlasService atlasF = atlas;
        final InputManagerService inputManagerF = inputManager;
        final TelephonyRegistry telephonyRegistryF = telephonyRegistry;
        final MediaRouterService mediaRouterF = mediaRouter;
        final MmsServiceBroker mmsServiceF = mmsService;
        mActivityManagerService.systemReady(new Runnable() {
            @Override
            public void run() {
                Slog.i(TAG, "Making services ready");
                mSystemServiceManager.startBootPhase(
                        SystemService.PHASE_ACTIVITY_MANAGER_READY);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "PhaseActivityManagerReady");
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartObservingNativeCrashes");
                try {
                    mActivityManagerService.startObservingNativeCrashes();
                } catch (Throwable e) {
                    reportWtf("observing native crashes", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                if (!mOnlyCore) {
                    Slog.i(TAG, "WebViewFactory preparation");
                    Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "WebViewFactoryPreparation");
                    mWebViewUpdateService.prepareWebViewInSystemServer();
                    Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                }
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartSystemUI");
                try {
                    startSystemUi(context);
                } catch (Throwable e) {
                    reportWtf("starting System UI", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeNetworkScoreReady");
                try {
                    if (networkScoreF != null) networkScoreF.systemReady();
                } catch (Throwable e) {
                    reportWtf("making Network Score Service ready", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeNetworkManagementServiceReady");
                try {
                    if (networkManagementF != null) networkManagementF.systemReady();
                } catch (Throwable e) {
                    reportWtf("making Network Managment Service ready", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeNetworkStatsServiceReady");
                try {
                    if (networkStatsF != null) networkStatsF.systemReady();
                } catch (Throwable e) {
                    reportWtf("making Network Stats Service ready", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeNetworkPolicyServiceReady");
                try {
                    if (networkPolicyF != null) networkPolicyF.systemReady();
                } catch (Throwable e) {
                    reportWtf("making Network Policy Service ready", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "MakeConnectivityServiceReady");
                try {
                    if (connectivityF != null) connectivityF.systemReady();
                } catch (Throwable e) {
                    reportWtf("making Connectivity Service ready", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Watchdog.getInstance().start();
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
                Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "PhaseThirdPartyAppsCanStart");
                mSystemServiceManager.startBootPhase(
                        SystemService.PHASE_THIRD_PARTY_APPS_CAN_START);
                try {
                    if (locationF != null) locationF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying Location Service running", e);
                }
                try {
                    if (countryDetectorF != null) countryDetectorF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying CountryDetectorService running", e);
                }
                try {
                    if (networkTimeUpdaterF != null) networkTimeUpdaterF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying NetworkTimeService running", e);
                }
                try {
                    if (commonTimeMgmtServiceF != null) {
                        commonTimeMgmtServiceF.systemRunning();
                    }
                } catch (Throwable e) {
                    reportWtf("Notifying CommonTimeManagementService running", e);
                }
                try {
                    if (atlasF != null) atlasF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying AssetAtlasService running", e);
                }
                try {
                    if (inputManagerF != null) inputManagerF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying InputManagerService running", e);
                }
                try {
                    if (telephonyRegistryF != null) telephonyRegistryF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying TelephonyRegistry running", e);
                }
                try {
                    if (mediaRouterF != null) mediaRouterF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying MediaRouterService running", e);
                }
                try {
                    if (mmsServiceF != null) mmsServiceF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying MmsService running", e);
                }
                try {
                    if (networkScoreF != null) networkScoreF.systemRunning();
                } catch (Throwable e) {
                    reportWtf("Notifying NetworkScoreService running", e);
                }
                Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
            }
        });
    }

    startOtherServices()方法很长，看看就好。

  • ActivityManagerService的创建和初始化

    ActivityManagerService（AMS）是android系统中一个非常重要的服务，它主要管理四大组件和进程内存的调度，它在SystemServer里的创建和启动，主要调用了一下几个方法：

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      mActivityManagerService = mSystemServiceManager.startService(
                      ActivityManagerService.Lifecycle.class).getService();
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      mActivityManagerService.setSystemProcess();
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      mActivityManagerService.systemReady();

    变量mSystemServiceManager是一个SystemServiceManager类型的对象，首先调用它的startService()方法创建AMS对象，接着调用这个AMS对象的setSystemProcess()方法来初始化AMS中的一些重要工作，最后调用systemReady()方法来判断AM是否启动和初始化成功。在android系统中，很多的核心服务都会提供systemReady()方法来判断它相应的服务是否启动和初始化成功，因为有些核心服务如果没有启动或者初始化失败，会严重影响系统的使用，如AMS，WMS等核心服务。而有些服务没有提供这个方法，比如MountService，因为MountService主要管理Sdcard这部分，如果这个服务没有启动或者初始化失败，只会影响sdcard，对系统的影响不是很大。

    首先来看一下startService()方法创建AMS对象。

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    public <T extends SystemService> T startService(Class<T> serviceClass) {
        try {
            // 首先获得name为ActivityManagerService.Lifecycle
            final String name = serviceClass.getName();
            Slog.i(TAG, "Starting " + name);
            Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartService " + name);
            if (!SystemService.class.isAssignableFrom(serviceClass)) {
                throw new RuntimeException("Failed to create " + name
                        + ": service must extend " + SystemService.class.getName());
            }
            final T service;
            try {
                Constructor<T> constructor = serviceClass.getConstructor(Context.class);
                // 通过构造方法的反射创建了一个实例，这里是Lifecycle对象
                service = constructor.newInstance(mContext);
            } catch (InstantiationException ex) {
                throw new RuntimeException("Failed to create service " + name
                        + ": service could not be instantiated", ex);
            } catch (IllegalAccessException ex) {
                throw new RuntimeException("Failed to create service " + name
                        + ": service must have a public constructor with a Context argument", ex);
            } catch (NoSuchMethodException ex) {
                throw new RuntimeException("Failed to create service " + name
                        + ": service must have a public constructor with a Context argument", ex);
            } catch (InvocationTargetException ex) {
                throw new RuntimeException("Failed to create service " + name
                        + ": service constructor threw an exception", ex);
            }
            mServices.add(service);
            try {
                service.onStart();
            } catch (RuntimeException ex) {
                throw new RuntimeException("Failed to start service " + name
                        + ": onStart threw an exception", ex);
            }
            return service;
        } finally {
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
        }
    }

    SystemServiceManager类的startService()方法创建了一个Lifecycle实例，然后返回，而在SystemServer类里通过这个返回的实例调用getService()方法就获得AMS对象。Lifecycle是AMS的内部类，在创建这个实例的时候，会调用它的构造方法。

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    public static final class Lifecycle extends SystemService {
        private final ActivityManagerService mService;
        public Lifecycle(Context context) {
            super(context);
            mService = new ActivityManagerService(context);
        }
        @Override
        public void onStart() {
            mService.start();
        }
        public ActivityManagerService getService() {
            return mService;
        }
    }

    Lifecycle的构造方法创建了一个AMS实例对象，而它的getService()方法会返回构造方法里创建的这个AMS实例对象。

    回到前面，接下来调用ActivityManagerService的setSystemProcess()方法。

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    public void setSystemProcess() {
        try {
            // 添加AMS到ServiceManager中
            ServiceManager.addService(Context.ACTIVITY_SERVICE, this, true);
            ServiceManager.addService(ProcessStats.SERVICE_NAME, mProcessStats);
            ServiceManager.addService("meminfo", new MemBinder(this));
            ServiceManager.addService("gfxinfo", new GraphicsBinder(this));
            ServiceManager.addService("dbinfo", new DbBinder(this));
            if (MONITOR_CPU_USAGE) {
                ServiceManager.addService("cpuinfo", new CpuBinder(this));
            }
            ServiceManager.addService("permission", new PermissionController(this));
            ServiceManager.addService("processinfo", new ProcessInfoService(this));
            ApplicationInfo info = mContext.getPackageManager().getApplicationInfo(
                    "android", STOCK_PM_FLAGS | MATCH_SYSTEM_ONLY);
            mSystemThread.installSystemApplicationInfo(info, getClass().getClassLoader());
            synchronized (this) {
                ProcessRecord app = newProcessRecordLocked(info, info.processName, false, 0);
                app.persistent = true;
                app.pid = MY_PID;
                app.maxAdj = ProcessList.SYSTEM_ADJ;
                app.makeActive(mSystemThread.getApplicationThread(), mProcessStats);
                synchronized (mPidsSelfLocked) {
                    mPidsSelfLocked.put(app.pid, app);
                }
                // 调整进程的调度优先级
                updateLruProcessLocked(app, false, null);
                // 调整OOM_Adj值
                updateOomAdjLocked();
            }
        } catch (PackageManager.NameNotFoundException e) {
            throw new RuntimeException(
                    "Unable to find android system package", e);
        }
    }

    最后，继续调用ActivityManagerService的systemReady()方法。

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    public void systemReady(final Runnable goingCallback) {
        synchronized(this) {
            if (mSystemReady) {
                if (goingCallback != null) {
                    goingCallback.run();
                }
                return;
            }
            mLocalDeviceIdleController
                    = LocalServices.getService(DeviceIdleController.LocalService.class);
            mUserController.onSystemReady();
            mRecentTasks.onSystemReadyLocked();
            mAppOpsService.systemReady();
            mSystemReady = true;
        }
        // 从mPidsSelfLocked中找到那些优先于AMS启动的进程，即manifest里声明persistent为true的那些进程
        ArrayList<ProcessRecord> procsToKill = null;
        synchronized(mPidsSelfLocked) {
            for (int i=mPidsSelfLocked.size()-1; i>=0; i--) {
                ProcessRecord proc = mPidsSelfLocked.valueAt(i);
                if (!isAllowedWhileBooting(proc.info)){
                    if (procsToKill == null) {
                        procsToKill = new ArrayList<ProcessRecord>();
                    }
                    procsToKill.add(proc);
                }
            }
        }
        // 找到这些进程之后，通过removeProcessLocked()方法把它关闭
        synchronized(this) {
            if (procsToKill != null) {
                for (int i=procsToKill.size()-1; i>=0; i--) {
                    ProcessRecord proc = procsToKill.get(i);
                    Slog.i(TAG, "Removing system update proc: " + proc);
                    removeProcessLocked(proc, true, false, "system update done");
                }
            }
            mProcessesReady = true;
        }
        Slog.i(TAG, "System now ready");
        EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_AMS_READY,
            SystemClock.uptimeMillis());
        synchronized(this) {
            if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL) {
                ResolveInfo ri = mContext.getPackageManager()
                        .resolveActivity(new Intent(Intent.ACTION_FACTORY_TEST),
                                STOCK_PM_FLAGS);
                CharSequence errorMsg = null;
                if (ri != null) {
                    ActivityInfo ai = ri.activityInfo;
                    ApplicationInfo app = ai.applicationInfo;
                    if ((app.flags&ApplicationInfo.FLAG_SYSTEM) != 0) {
                        mTopAction = Intent.ACTION_FACTORY_TEST;
                        mTopData = null;
                        mTopComponent = new ComponentName(app.packageName,
                                ai.name);
                    } else {
                        errorMsg = mContext.getResources().getText(
                                com.android.internal.R.string.factorytest_not_system);
                    }
                } else {
                    errorMsg = mContext.getResources().getText(
                            com.android.internal.R.string.factorytest_no_action);
                }
                if (errorMsg != null) {
                    mTopAction = null;
                    mTopData = null;
                    mTopComponent = null;
                    Message msg = Message.obtain();
                    msg.what = SHOW_FACTORY_ERROR_UI_MSG;
                    msg.getData().putCharSequence("msg", errorMsg);
                    mUiHandler.sendMessage(msg);
                }
            }
        }
        // 查询settings数据库，因为AMS会用到一些settings数据库里的数据
        retrieveSettings();
        final int currentUserId;
        synchronized (this) {
            currentUserId = mUserController.getCurrentUserIdLocked();
            readGrantedUriPermissionsLocked();
        }
        if (goingCallback != null) goingCallback.run();
        mBatteryStatsService.noteEvent(BatteryStats.HistoryItem.EVENT_USER_RUNNING_START,
                Integer.toString(currentUserId), currentUserId);
        mBatteryStatsService.noteEvent(BatteryStats.HistoryItem.EVENT_USER_FOREGROUND_START,
                Integer.toString(currentUserId), currentUserId);
        mSystemServiceManager.startUser(currentUserId);
        synchronized (this) {
            startPersistentApps(PackageManager.MATCH_DIRECT_BOOT_AWARE);
            mBooting = true;
            if (UserManager.isSplitSystemUser()) {
                ComponentName cName = new ComponentName(mContext, SystemUserHomeActivity.class);
                try {
                    AppGlobals.getPackageManager().setComponentEnabledSetting(cName,
                            PackageManager.COMPONENT_ENABLED_STATE_ENABLED, 0,
                            UserHandle.USER_SYSTEM);
                } catch (RemoteException e) {
                    throw e.rethrowAsRuntimeException();
                }
            }
            // 启动Launcher
            startHomeActivityLocked(currentUserId, "systemReady");
            try {
                if (AppGlobals.getPackageManager().hasSystemUidErrors()) {
                    Slog.e(TAG, "UIDs on the system are inconsistent, you need to wipe your"
                            + " data partition or your device will be unstable.");
                    mUiHandler.obtainMessage(SHOW_UID_ERROR_UI_MSG).sendToTarget();
                }
            } catch (RemoteException e) {
            }
            if (!Build.isBuildConsistent()) {
                Slog.e(TAG, "Build fingerprint is not consistent, warning user");
                mUiHandler.obtainMessage(SHOW_FINGERPRINT_ERROR_UI_MSG).sendToTarget();
            }
            long ident = Binder.clearCallingIdentity();
            try {
                Intent intent = new Intent(Intent.ACTION_USER_STARTED);
                intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY
                        | Intent.FLAG_RECEIVER_FOREGROUND);
                intent.putExtra(Intent.EXTRA_USER_HANDLE, currentUserId);
                broadcastIntentLocked(null, null, intent,
                        null, null, 0, null, null, null, AppOpsManager.OP_NONE,
                        null, false, false, MY_PID, Process.SYSTEM_UID,
                        currentUserId);
                intent = new Intent(Intent.ACTION_USER_STARTING);
                intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
                intent.putExtra(Intent.EXTRA_USER_HANDLE, currentUserId);
                broadcastIntentLocked(null, null, intent,
                        null, new IIntentReceiver.Stub() {
                            @Override
                            public void performReceive(Intent intent, int resultCode, String data,
                                    Bundle extras, boolean ordered, boolean sticky, int sendingUser)
                                    throws RemoteException {
                            }
                        }, 0, null, null,
                        new String[] {INTERACT_ACROSS_USERS}, AppOpsManager.OP_NONE,
                        null, true, false, MY_PID, Process.SYSTEM_UID, UserHandle.USER_ALL);
            } catch (Throwable t) {
                Slog.wtf(TAG, "Failed sending first user broadcasts", t);
            } finally {
                Binder.restoreCallingIdentity(ident);
            }
            mStackSupervisor.resumeFocusedStackTopActivityLocked();
            mUserController.sendUserSwitchBroadcastsLocked(-1, currentUserId);
        }
    }

    至此，ActivityManagerService的创建和它的核心方法的调用分析完毕。