本文源代码基于 Android 7.0。
SystemServer 由 Zygote fork 生成，进程名为 system_server，该进程承载着 Framework 的核心服务。关于 Zygote 的启动流程，到 SystemServer 的启动入口，可以参考这篇文章：
Framework篇 – zygote 进程分析
目录：
- SystemServer 进程创建流程
- SystemServer main() 工作内容
1. SystemServer 进程创建流程
-
1.1 ZygoteInit.startSystemServer()
/base/core/java/com/android/internal/os/ZygoteInit.java
/**
* 启动SystemServer进程
*
* 准备参数并fork新进程，从上面可以看出system server进程参数信息为uid=1000,gid=1000,进程名为sytem_server，
* 从zygote进程fork新进程后，需要关闭zygote原有的socket。另外，对于有两个zygote进程情况，需等待第2个zygote创建完成。
*/
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
);
/* Containers run without this capability, so avoid setting it in that case */
if (!SystemProperties.getBoolean(PROPERTY_RUNNING_IN_CONTAINER, false)) {
capabilities |= posixCapabilitiesAsBits(OsConstants.CAP_BLOCK_SUSPEND);
}
// 参数准备
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 {
// 用于解析参数，生成目标格式，使用socket fork
parsedArgs = new ZygoteConnection.Arguments(args);
ZygoteConnection.applyDebuggerSystemProperty(parsedArgs);
ZygoteConnection.applyInvokeWithSystemProperty(parsedArgs);
// fork子进程，用于运行system_server
pid = Zygote.forkSystemServer(
parsedArgs.uid, parsedArgs.gid,
parsedArgs.gids,
parsedArgs.debugFlags,
null,
parsedArgs.permittedCapabilities,
parsedArgs.effectiveCapabilities);
} catch (IllegalArgumentException ex) {
throw new RuntimeException(ex);
}
//进入子进程system_server
if (pid == 0) {
if (hasSecondZygote(abiList)) {
waitForSecondaryZygote(socketName);
}
// 完成system_server进程剩余的工作
handleSystemServerProcess(parsedArgs);
}
return true;
}
准备参数并 fork 新进程，从上面可以看出 system server 进程参数信息为 uid=1000, gid=1000, 进程名为 sytem_server，从zygote 进程 fork 新进程后，需要关闭 zygote 原有的 socket。另外，对于有两个 zygote 进程情况，需等待第2个 zygote 创建完成。
-
1.2 Zygote.forkSystemServer()
/base/core/java/com/android/internal/os/Zygote.java
public static int forkSystemServer(int uid, int gid, int[] gids, int debugFlags,
int[][] rlimits, long permittedCapabilities, long effectiveCapabilities) {
VM_HOOKS.preFork();
// 调用nativeForkSystemServer函数 com_android_internal_os_Zygote.cpp -> nativeForkSystemServer
int pid = nativeForkSystemServer(
uid, gid, gids, debugFlags, rlimits, permittedCapabilities, effectiveCapabilities);
// Enable tracing as soon as we enter the system_server.
if (pid == 0) {
Trace.setTracingEnabled(true);
}
VM_HOOKS.postForkCommon();
return pid;
}
native private static int nativeForkSystemServer(int uid, int gid, int[] gids, int debugFlags,
int[][] rlimits, long permittedCapabilities, long effectiveCapabilities);-
1.3 com_android_internal_os_Zygote.nativeForkSystemServer()
/base/core/jni/com_android_internal_os_Zygote.cpp
// fork SystemServer 进程
/**
* 当system_server进程创建失败时，将会重启zygote进程。
这里需要注意，对于Android 5.0以上系统，有两个zygote进程，分别是zygote、zygote64两个进程，system_server的父进程，一般来说64位系统其父进程是zygote64进程
当kill system_server进程后，只重启zygote64和system_server，不重启zygote;
当kill zygote64进程后，只重启zygote64和system_server，也不重启zygote；
当kill zygote进程，则重启zygote、zygote64以及system_server。
*/
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) {
// fork子进程
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) {
// The zygote process checks whether the child process has died or not.
ALOGI("System server process %d has been created", pid);
// zygote进程，检测system_server进程是否创建
gSystemServerPid = pid;
// There is a slight window that the system server process has crashed
// but it went unnoticed because we haven't published its pid yet. So
// we recheck here just to make sure that all is well.
int status;
if (waitpid(pid, &status, WNOHANG) == pid) {
ALOGE("System server process %d has died. Restarting Zygote!", pid);
// 当system_server进程死亡后，重启zygote进程
RuntimeAbort(env, __LINE__, "System server process has died. Restarting Zygote!");
}
}
return pid;
}-
1.4 com_android_internal_os_Zygote.ForkAndSpecializeCommon()
/base/core/jni/com_android_internal_os_Zygote.cpp
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(); //设置子进程的signal信号处理函数
pid_t pid = fork(); //fork子进程
if (pid == 0) {
//进入子进程
DetachDescriptors(env, fdsToClose); //关闭并清除文件描述符
if (!is_system_server) {
//对于非system_server子进程，则创建进程组
int rc = createProcessGroup(uid, getpid());
}
SetGids(env, javaGids); //设置设置group
SetRLimits(env, javaRlimits); //设置资源limit
int rc = setresgid(gid, gid, gid);
rc = setresuid(uid, uid, uid);
SetCapabilities(env, permittedCapabilities, effectiveCapabilities);
SetSchedulerPolicy(env); //设置调度策略
//selinux上下文
rc = selinux_android_setcontext(uid, is_system_server, se_info_c_str, se_name_c_str);
if (se_info_c_str == NULL && is_system_server) {
se_name_c_str = "system_server";
}
if (se_info_c_str != NULL) {
SetThreadName(se_name_c_str); //设置线程名为system_server，方便调试
}
UnsetSigChldHandler(); //设置子进程的signal信号处理函数为默认函数
//等价于调用zygote.callPostForkChildHooks()
env->CallStaticVoidMethod(gZygoteClass, gCallPostForkChildHooks, debug_flags,
is_system_server ? NULL : instructionSet);
...
} else if (pid > 0) {
//进入父进程，即zygote进程
}
return pid;
}fork() 创建新进程，采用 copy on write 方式，这是 Linux 创建进程的标准方法，会有两次 return，对于 pid==0 为子进程的返回，对于 pid>0 为父进程的返回。 到此 system_server 进程已完成了创建的所有工作，接下来开始了 system_server 进程的真正工作。在前面 startSystemServer() 方法中，zygote 进程执行完 forkSystemServer() 后，新创建出来的 system_server 进程便进入 handleSystemServerProcess() 方法。关于fork()，下一篇文章会具体讲解。
-
1.5 ZygoteInit.handleSystemServerProcess()
/base/core/java/com/android/internal/os/ZygoteInit.java
完成 system_server 进程剩余的工作：
private static void handleSystemServerProcess( ZygoteConnection.Arguments parsedArgs) throws ZygoteInit.MethodAndArgsCaller {
closeServerSocket(); //关闭父进程zygote复制而来的Socket
Os.umask(S_IRWXG | S_IRWXO);
if (parsedArgs.niceName != null) {
Process.setArgV0(parsedArgs.niceName); //设置当前进程名为"system_server"
}
final String systemServerClasspath = Os.getenv("SYSTEMSERVERCLASSPATH");
if (systemServerClasspath != null) {
//执行dex优化操作
performSystemServerDexOpt(systemServerClasspath);
}
if (parsedArgs.invokeWith != null) {
String[] args = parsedArgs.remainingArgs;
if (systemServerClasspath != null) {
String[] amendedArgs = new String[args.length + 2];
amendedArgs[0] = "-cp";
amendedArgs[1] = systemServerClasspath;
System.arraycopy(parsedArgs.remainingArgs, 0, amendedArgs, 2, parsedArgs.remainingArgs.length);
}
// 启动应用进程
WrapperInit.execApplication(parsedArgs.invokeWith,
parsedArgs.niceName, parsedArgs.targetSdkVersion,
VMRuntime.getCurrentInstructionSet(), null, args);
} else {
ClassLoader cl = null;
if (systemServerClasspath != null) {
// 创建类加载器，并赋予当前线程
cl = new PathClassLoader(systemServerClasspath, ClassLoader.getSystemClassLoader());
Thread.currentThread().setContextClassLoader(cl);
}
//system_server故进入此分支
RuntimeInit.zygoteInit(parsedArgs.targetSdkVersion, parsedArgs.remainingArgs, cl);
}
/* should never reach here */
}此处 systemServerClasspath 环境变量主要有 /system/framework/ 目录下的 services.jar，ethernet-service.jar, wifi-service.jar这3个文件。最后一句，调用 RuntimeInit.zygoteInit()：
RuntimeInit.zygoteInit(parsedArgs.targetSdkVersion, parsedArgs.remainingArgs, cl);
-
1.6 RuntimeInit.zygoteInit()
/base/core/java/com/android/internal/os/RuntimeInit.java
public static final void zygoteInit(int targetSdkVersion, String[] argv, ClassLoader classLoader)
throws ZygoteInit.MethodAndArgsCaller {
if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application from zygote");
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "RuntimeInit");
// 重定向log输出
redirectLogStreams();
// 通用的一些初始化
commonInit();
// zygote初始化
nativeZygoteInit();
// 应用初始化
applicationInit(targetSdkVersion, argv, classLoader);
}-
1.7 RuntimeInit.commonInit()
/base/core/java/com/android/internal/os/RuntimeInit.java
private static final void commonInit() {
// 设置默认的未捕捉异常处理方法
Thread.setDefaultUncaughtExceptionHandler(new UncaughtHandler());
// 设置市区，中国时区为"Asia/Shanghai"
TimezoneGetter.setInstance(new TimezoneGetter() {
@Override
public String getId() {
return SystemProperties.get("persist.sys.timezone");
}
});
TimeZone.setDefault(null);
// 重置log配置
LogManager.getLogManager().reset();
new AndroidConfig();
// 设置默认的HTTP User-agent格式,用于 HttpURLConnection。
String userAgent = getDefaultUserAgent();
System.setProperty("http.agent", userAgent);
// 设置socket的tag，用于网络流量统计
NetworkManagementSocketTagger.install();
}-
1.8 AndroidRuntime.nativeZygoteInit()
/base/core/jni/AndroidRuntime.cpp
static void com_android_internal_os_RuntimeInit_nativeZygoteInit(JNIEnv* env, jobject clazz)
{
gCurRuntime->onZygoteInit();
}
-
1.9 app_main.onZygoteInit()
/base/cmds/app_process/app_main.cpp
virtual void onZygoteInit() {
sp<ProcessState> proc = ProcessState::self();
proc->startThreadPool(); //启动新binder线程
}ProcessState::self() 是单例模式，主要工作是调用 open() 打开 /dev/binder 驱动设备，再利用 mmap() 映射内核的地址空间，将Binder 驱动的 fd 赋值 ProcessState 对象中的变量 mDriverFD，用于交互操作。startThreadPool() 是创建一个新的 Binder 线程，不断进行 talkWithDriver()。
-
1.10 RuntimeInit.applicationInit()
/base/core/java/com/android/internal/os/RuntimeInit.java
private static void applicationInit(int targetSdkVersion, String[] argv, ClassLoader classLoader) throws ZygoteInit.MethodAndArgsCaller {
//true代表应用程序退出时不调用AppRuntime.onExit()，否则会在退出前调用
nativeSetExitWithoutCleanup(true);
//设置虚拟机的内存利用率参数值为0.75
VMRuntime.getRuntime().setTargetHeapUtilization(0.75f);
VMRuntime.getRuntime().setTargetSdkVersion(targetSdkVersion);
final Arguments args;
try {
args = new Arguments(argv); //解析参数
} catch (IllegalArgumentException ex) {
return;
}
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
//调用startClass的static方法 main()
invokeStaticMain(args.startClass, args.startArgs, classLoader);
}-
1.11 RuntimeInit.invokeStaticMain()
/base/core/java/com/android/internal/os/RuntimeInit.java
在 startSystemServer() 方法中通过硬编码初始化参数，可知此处 className 为 “com.android.server.SystemServer”
private static void invokeStaticMain(String className, String[] argv, ClassLoader classLoader)
throws ZygoteInit.MethodAndArgsCaller {
Class<?> cl;
try {
cl = Class.forName(className, true, classLoader);
} catch (ClassNotFoundException ex) {
throw new RuntimeException(
"Missing class when invoking static main " + className,
ex);
}
Method m;
try {
m = cl.getMethod("main", new Class[] { String[].class });
} catch (NoSuchMethodException ex) {
throw new RuntimeException(
"Missing static main on " + className, ex);
} catch (SecurityException ex) {
throw new RuntimeException(
"Problem getting static main on " + className, ex);
}
int modifiers = m.getModifiers();
if (! (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))) {
throw new RuntimeException(
"Main method is not public and static on " + className);
}
throw new ZygoteInit.MethodAndArgsCaller(m, argv);
}这就进入到了 SystemServer 类的 main() 方法。
2. SystemServer main() 工作内容
上面经过 Zygote fork 出 system server 进程，然后执行初始化工作，最终反射出 com.android.server.SystemServer 这个 Java 类，并执行其 main() 方法。
/base/services/java/com/android/server/SystemServer.java
-
2.1 SystemServer.main()
public static void main(String[] args) {
// 先初始化SystemServer对象，再调用对象的run()方法
new SystemServer().run();
}-
2.2 SystemServer.run()
private void run() {
try {
// 当系统时间比1970年更早，就设置当前系统时间为1970年
if (System.currentTimeMillis() < EARLIEST_SUPPORTED_TIME) {
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", "");
}
// 变更虚拟机的库文件，对于Android 6.0默认采用的是libart.so
SystemProperties.set("persist.sys.dalvik.vm.lib.2", VMRuntime.getRuntime().vmLibrary());
// ...
// 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();
// 设置内存的可能有效使用率为0.8
VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);
// Some devices rely on runtime fingerprint generation, so make sure
// we've defined it before booting further.
// 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);
// ...
// 确保当前系统进程的binder调用，总是运行在前台优先级(foreground priority)
BinderInternal.disableBackgroundScheduling(true);
// Increase the number of binder threads in system_server
BinderInternal.setMaxThreads(sMaxBinderThreads);
android.os.Process.setThreadPriority(
android.os.Process.THREAD_PRIORITY_FOREGROUND);
android.os.Process.setCanSelfBackground(false);
// 主线程looper就在当前线程运行
Looper.prepareMainLooper();
// 加载android_servers.so库，该库包含的源码在frameworks/base/services/目录下
System.loadLibrary("android_servers");
// 检测上次关机过程是否失败，该方法可能不会返回[见小节1.2.1]
performPendingShutdown();
// Initialize the system context.
// 初始化系统上下文 【见小节1.3】
createSystemContext();
// Create the system service manager.
// 创建系统服务管理
mSystemServiceManager = new SystemServiceManager(mSystemContext);
// 将mSystemServiceManager添加到本地服务的成员sLocalServiceObjects
LocalServices.addService(SystemServiceManager.class, mSystemServiceManager);
} finally {
Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
}
// 启动各种系统服务
try {
Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartServices");
startBootstrapServices(); // 启动引导服务
startCoreServices(); // 启动核心服务
startOtherServices(); // 启动其他服务
} catch (Throwable ex) {
throw ex;
} finally {
Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
}
// 用于debug版本，将log事件不断循环地输出到dropbox（用于分析）
if (StrictMode.conditionallyEnableDebugLogging()) {
Slog.i(TAG, "Enabled StrictMode for system server main thread.");
}
// 一直循环执行
// 到此, System_server主线程的启动工作总算完成, 进入Looper.loop()状态,等待其他线程通过handler发送消息到主线程再处理.
Looper.loop();
throw new RuntimeException("Main thread loop unexpectedly exited");
}主要两件事：
- 创建主线程 ActivityThread，启动 main looper，接收任务。
- 启动各种服务。
每一个进程都会创建属于它自己的主线程：ActivityThread。
-
2.3 SystemServer.createSystemContext()
private void createSystemContext() {
//创建system_server进程的上下文信息
ActivityThread activityThread = ActivityThread.systemMain();
mSystemContext = activityThread.getSystemContext();
//设置主题
mSystemContext.setTheme(android.R.style.Theme_DeviceDefault_Light_DarkActionBar);
}该过程会创建对象有ActivityThread，Instrumentation, ContextImpl，LoadedApk，Application。
-
2.4 SystemServer.startBootstrapServices()
启动引导服务：
private void startBootstrapServices() {
//阻塞等待与installd建立socket通道
Installer installer = mSystemServiceManager.startService(Installer.class);
//启动服务ActivityManagerService
mActivityManagerService = mSystemServiceManager.startService(
ActivityManagerService.Lifecycle.class).getService();
mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
mActivityManagerService.setInstaller(installer);
//启动服务PowerManagerService
mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);
//初始化power management
mActivityManagerService.initPowerManagement();
//启动服务LightsService
mSystemServiceManager.startService(LightsService.class);
//启动服务DisplayManagerService
mDisplayManagerService = mSystemServiceManager.startService(DisplayManagerService.class);
//Phase100: 在初始化package manager之前，需要默认的显示.
mSystemServiceManager.startBootPhase(SystemService.PHASE_WAIT_FOR_DEFAULT_DISPLAY);
//当设备正在加密时，仅运行核心
String cryptState = SystemProperties.get("vold.decrypt");
if (ENCRYPTING_STATE.equals(cryptState)) {
mOnlyCore = true;
} else if (ENCRYPTED_STATE.equals(cryptState)) {
mOnlyCore = true;
}
//启动服务PackageManagerService
mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF, mOnlyCore);
mFirstBoot = mPackageManagerService.isFirstBoot();
mPackageManager = mSystemContext.getPackageManager();
//启动服务UserManagerService，新建目录/data/user/
ServiceManager.addService(Context.USER_SERVICE, UserManagerService.getInstance());
AttributeCache.init(mSystemContext);
//设置AMS
mActivityManagerService.setSystemProcess();
//启动传感器服务
startSensorService();
}创建各种服务，服务内部会处理加入到 ServiceManager 的逻辑。
-
2.5 SystemServer.startCoreServices()
启动核心服务：
private void startCoreServices() {
// Tracks the battery level. Requires LightService.
// 启动服务BatteryService，用于统计电池电量，需要LightService.
mSystemServiceManager.startService(BatteryService.class);
// Tracks application usage stats.
// 启动服务UsageStatsService，用于统计应用使用情况
mSystemServiceManager.startService(UsageStatsService.class);
mActivityManagerService.setUsageStatsManager(
LocalServices.getService(UsageStatsManagerInternal.class));
// Tracks whether the updatable WebView is in a ready state and watches for update installs.
// 启动服务WebViewUpdateService
mWebViewUpdateService = mSystemServiceManager.startService(WebViewUpdateService.class);
}-
2.6 SystemServer.startOtherServices()
启动其他服务：
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;
// 启动InputManagerService
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);
// The AccountManager must come before the ContentService
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);
// ...
}
- 引导服务(7个)：ActivityManagerService、PowerManagerService、LightsService、DisplayManagerService、PackageManagerService、UserManagerService、SensorService。
- 核心服务(3个)：BatteryService、UsageStatsService、WebViewUpdateService。
- 其他服务(70个+)：AlarmManagerService、VibratorService等，合计总大约80个系统服务。
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