本文详细解读了SystemServer进程在Zygote进程中的创建、属性配置、fork系统服务器的过程，直至SystemServer进程启动执行的主要操作。包括进程名称设置、权限与能力配置、进程初始化与线程管理等关键步骤，以及SystemServer进程内部启动流程，如Socket关闭、系统输出流设置、进程名称设置、应用执行与Binder初始化等。
SystemServer进程创建过程
SystemServer进程名称为System_Server，在Zygote进程启动过程源码分析一文中介绍了zygote进程通过startSystemServer函数调用将启动一个SystemServer子进程：
private static boolean startSystemServer()
throws MethodAndArgsCaller, RuntimeException {
/* Hardcoded command line to start the system server */
String args[] = {
"--setuid=1000",
"--setgid=1000",
"--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,3001,3002,3003,3006,3007",
"--capabilities=130104352,130104352",
"--runtime-init",
"--nice-name=system_server",
"com.android.server.SystemServer",
};
ZygoteConnection.Arguments parsedArgs = null;
int pid;
try {
//参数解析
parsedArgs = new ZygoteConnection.Arguments(args);
//打开系统调试属性
ZygoteConnection.applyDebuggerSystemProperty(parsedArgs);
ZygoteConnection.applyInvokeWithSystemProperty(parsedArgs);
/* 请求fork SystemServer进程*/
pid = Zygote.forkSystemServer(
parsedArgs.uid, parsedArgs.gid,
parsedArgs.gids,
parsedArgs.debugFlags,
null,
parsedArgs.permittedCapabilities,
parsedArgs.effectiveCapabilities);
} catch (IllegalArgumentException ex) {
throw new RuntimeException(ex);
}
/* pid为0表示子进程，即SystemServer进程，从此SystemServer进程与Zygote进程分道扬镳*/
if (pid == 0) {
handleSystemServerProcess(parsedArgs);
}
return true;
}参数解析
private void parseArgs(String args[])throws IllegalArgumentException {
int curArg = 0;
//遍历所有的命令参数
for ( /* curArg */ ; curArg < args.length; curArg++) {
String arg = args[curArg];
if (arg.equals("--")) {
curArg++;
break;
} else if (arg.startsWith("--setuid=")) {
if (uidSpecified) {
throw new IllegalArgumentException("Duplicate arg specified");
}
uidSpecified = true;
//uid = 1000
uid = Integer.parseInt(arg.substring(arg.indexOf('=') + 1));
} else if (arg.startsWith("--setgid=")) {
if (gidSpecified) {
throw new IllegalArgumentException("Duplicate arg specified");
}
gidSpecified = true;
//gid =1000
gid = Integer.parseInt(arg.substring(arg.indexOf('=') + 1));
} else if (arg.startsWith("--target-sdk-version=")) {
if (targetSdkVersionSpecified) {
throw new IllegalArgumentException("Duplicate target-sdk-version specified");
}
targetSdkVersionSpecified = true;
targetSdkVersion = Integer.parseInt(arg.substring(arg.indexOf('=') + 1));
} else if (arg.equals("--enable-debugger")) {
debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
} else if (arg.equals("--enable-safemode")) {
debugFlags |= Zygote.DEBUG_ENABLE_SAFEMODE;
} else if (arg.equals("--enable-checkjni")) {
debugFlags |= Zygote.DEBUG_ENABLE_CHECKJNI;
} else if (arg.equals("--enable-jni-logging")) {
debugFlags |= Zygote.DEBUG_ENABLE_JNI_LOGGING;
} else if (arg.equals("--enable-assert")) {
debugFlags |= Zygote.DEBUG_ENABLE_ASSERT;
} else if (arg.equals("--peer-wait")) {
peerWait = true;
} else if (arg.equals("--runtime-init")) {
//runtimeInit = true
runtimeInit = true;
} else if (arg.startsWith("--capabilities=")) {
if (capabilitiesSpecified) {
throw new IllegalArgumentException("Duplicate arg specified");
}
capabilitiesSpecified = true;
String capString = arg.substring(arg.indexOf('=')+1);
String[] capStrings = capString.split(",", 2);
if (capStrings.length == 1) {
effectiveCapabilities = Long.decode(capStrings[0]);
permittedCapabilities = effectiveCapabilities;
} else {
//permittedCapabilities = 130104352
//effectiveCapabilities = 130104352
permittedCapabilities = Long.decode(capStrings[0]);
effectiveCapabilities = Long.decode(capStrings[1]);
}
} else if (arg.startsWith("--rlimit=")) {
// Duplicate --rlimit arguments are specifically allowed.
String[] limitStrings = arg.substring(arg.indexOf('=')+1).split(",");
if (limitStrings.length != 3) {
throw new IllegalArgumentException("--rlimit= should have 3 comma-delimited ints");
}
int[] rlimitTuple = new int[limitStrings.length];
for(int i=0; i < limitStrings.length; i++) {
rlimitTuple[i] = Integer.parseInt(limitStrings[i]);
}
if (rlimits == null) {
rlimits = new ArrayList();
}
rlimits.add(rlimitTuple);
} else if (arg.equals("-classpath")) {
if (classpath != null) {
throw new IllegalArgumentException("Duplicate arg specified");
}
try {
classpath = args[++curArg];
} catch (IndexOutOfBoundsException ex) {
throw new IllegalArgumentException("-classpath requires argument");
}
} else if (arg.startsWith("--setgroups=")) {
if (gids != null) {
throw new IllegalArgumentException("Duplicate arg specified");
}
//1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,3001,3002,3003,3006,3007
String[] params= arg.substring(arg.indexOf('=') + 1).split(",");
gids = new int[params.length];
for (int i = params.length - 1; i >= 0 ; i--) {
gids[i] = Integer.parseInt(params[i]);
}
} else if (arg.equals("--invoke-with")) {
if (invokeWith != null) {
throw new IllegalArgumentException("Duplicate arg specified");
}
try {
invokeWith = args[++curArg];
} catch (IndexOutOfBoundsException ex) {
throw new IllegalArgumentException("--invoke-with requires argument");
}
} else if (arg.startsWith("--nice-name=")) {
if (niceName != null) {
throw new IllegalArgumentException("Duplicate arg specified");
}
//niceName = system_server
niceName = arg.substring(arg.indexOf('=') + 1);
} else {
break;
}
}
//runtimeInit = true classpath == null
if (runtimeInit && classpath != null) {
throw new IllegalArgumentException("--runtime-init and -classpath are incompatible");
}
remainingArgs = new String[args.length - curArg];
//remainingArgs = "com.android.server.SystemServer"
System.arraycopy(args, curArg, remainingArgs, 0,remainingArgs.length);
}属性配置
public static void applyDebuggerSystemProperty(Arguments args) {
if ("1".equals(SystemProperties.get("ro.debuggable"))) {
args.debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
}
}
public static void applyInvokeWithSystemProperty(Arguments args) {
if (args.invokeWith == null && args.niceName != null) { //true
if (args.niceName != null) {
String property = "wrap." + args.niceName; //wrap.system_server
if (property.length() > 31) {
property = property.substring(0, 31);
}
args.invokeWith = SystemProperties.get(property);
if (args.invokeWith != null && args.invokeWith.length() == 0) {
args.invokeWith = null;
}
}
}
}fork SystemServer进程
通过调用forkSystemServer函数来完成的
public static int forkSystemServer(int uid, int gid, int[] gids,
int debugFlags, int[][] rlimits,
long permittedCapabilities, long effectiveCapabilities) {
//停止Zygote进程中的其他线程，保证单线程
preFork();
int pid = nativeForkSystemServer(uid, gid, gids, debugFlags, rlimits,
permittedCapabilities,
effectiveCapabilities);
//启动垃圾回收后台线程
postFork();
return pid;
}
private static void preFork() {
Daemons.stop(); //停止进程内的其他后台线程
waitUntilAllThreadsStopped(); //等待
}
/**
* We must not fork until we're single-threaded again. Wait until /proc shows we're
* down to just one thread.
*/
private static void waitUntilAllThreadsStopped() {
File tasks = new File("/proc/self/task");//如果/proc/self/task目录下的文件个数大于1，说明还有其他线程在运行
while (tasks.list().length > 1) {
try {
// Experimentally, booting and playing about with a stingray, I never saw us
// go round this loop more than once with a 10ms sleep.
Thread.sleep(10);
} catch (InterruptedException ignored) {
}
}
}
private static void postFork() {
Daemons.start();
}最后调用native函数nativeForkAndSpecialize来fork出systemserver进程
native public static int nativeForkSystemServer(int uid, int gid,int[] gids, int debugFlags, int[][] rlimits,
long permittedCapabilities, long effectiveCapabilities);
{ "nativeForkSystemServer", "(II[II[[IJJ)I", Dalvik_dalvik_system_Zygote_forkSystemServer },根据JNI函数映射关系，最终会调用C++的Dalvik_dalvik_system_Zygote_forkSystemServer函数，在dalvik_system_Zygote.c文件中实现：
static void Dalvik_dalvik_system_Zygote_forkSystemServer(const u4* args, JValue* pResult)
{
pid_t pid;
//根据参数，fork一个子进程
pid = forkAndSpecializeCommon(args, true);
/* The zygote process checks whether the child process has died or not. */
if (pid > 0) {
int status;
ALOGI("System server process %d has been created", pid);
gDvm.systemServerPid = 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.
*/
if (waitpid(pid, &status, WNOHANG) == pid) {
ALOGE("System server process %d has died. Restarting Zygote!", pid);
/*kill(getpid(), SIGKILL);*/
sleep(15);
//如果SystemServer进程退出，zygote将杀死自身进程
#ifdef HOST_DALVIK
reboot(RB_AUTOBOOT);
#else
android_reboot(ANDROID_RB_RESTART2, 0, (char *)"special-systemserver-died");
#endif
}
}
RETURN_INT(pid);
}真正创建进程的核心函数：
static pid_t forkAndSpecializeCommon(const u4* args, bool isSystemServer)
{
..........
pid = fork(); //使用Linux 系统调用fork来创建进程
if (pid == 0) {
//设置子进程的uid，gid等参数
} else if (pid > 0) {
/* the parent process */
}
return pid;
}SystemServer进程启动过程
新创建的进程会执行handleSystemServerProcess函数，来完成自己的使命。
private static void handleSystemServerProcess(ZygoteConnection.Arguments parsedArgs)
throws ZygoteInit.MethodAndArgsCaller {
//因为SystemServer是从Zygote进程中复制过来的，所有需要关闭从zygote继承下来的socket
closeServerSocket();
// set umask to 0077 so new files and directories will default to owner-only permissions.
FileUtils.setUMask(FileUtils.S_IRWXG | FileUtils.S_IRWXO);
//设置进程名称
if (parsedArgs.niceName != null) {
Process.setArgV0(parsedArgs.niceName);
}
//parsedArgs.invokeWith == null
if (parsedArgs.invokeWith != null) {
WrapperInit.execApplication(parsedArgs.invokeWith,
parsedArgs.niceName, parsedArgs.targetSdkVersion,
null, parsedArgs.remainingArgs);
} else {
//传递剩余参数给SystemServer并调用zygoteInit函数
// "--nice-name=system_server com.android.server.SystemServer"
RuntimeInit.zygoteInit(parsedArgs.targetSdkVersion, parsedArgs.remainingArgs);
}
}RuntimeInit.java
public static final void zygoteInit(String[] argv)
throws ZygoteInit.MethodAndArgsCaller {
//设置系统输出流
System.setOut(new AndroidPrintStream(Log.INFO, "System.out"));
System.setErr(new AndroidPrintStream(Log.WARN, "System.err"));
//常规初始化
commonInit();
//执行一个Binder进程间通信机制的初始化工作，这个工作完成之后，这个进程中的Binder对象就可以方便地进行进程间通信了
zygoteInitNative();
int curArg = 0;
//argv = ["--nice-name=system_server， com.android.server.SystemServer"]
for ( ; curArg < argv.length; curArg++) {
String arg = argv[curArg];
if (arg.equals("--")) {
curArg++;
break;
} else if (!arg.startsWith("--")) {
break;
} else if (arg.startsWith("--nice-name=")) {
String niceName = arg.substring(arg.indexOf('=') + 1);
Process.setArgV0(niceName);//设置进程名称为system_server
}
}
if (curArg == argv.length) {
Slog.e(TAG, "Missing classname argument to RuntimeInit!");
// let the process exit
return;
}
// Remaining arguments are passed to the start class's static main
String startClass = argv[curArg++];//startClass =“com.android.server.SystemServer”
String[] startArgs = new String[argv.length - curArg];
System.arraycopy(argv, curArg, startArgs, 0, startArgs.length);
//调用SystemServer类中的main函数
invokeStaticMain(startClass, startArgs);
}这个函数会执行两个操作:
一个是调用zygoteInitNative函数来执行一个Binder进程间通信机制的初始化工作;
一个是调用com.android.server.SystemServer类的main函数;
public static final native void zygoteInitNative();static JNINativeMethod gMethods[] =
{
{ "finishInit", "()V",(void*) com_android_internal_os_RuntimeInit_finishInit },
{ "zygoteInitNative", "()V",(void*) com_android_internal_os_RuntimeInit_zygoteInit },
{ "isComputerOn", "()I",(void*) com_android_internal_os_RuntimeInit_isComputerOn },
{ "turnComputerOn", "()V",(void*) com_android_internal_os_RuntimeInit_turnComputerOn },
{ "getQwertyKeyboard", "()I",(void*) com_android_internal_os_RuntimeInit_getQwertyKeyboard },
};static void com_android_internal_os_RuntimeInit_zygoteInit(JNIEnv* env, jobject clazz)
{
gCurRuntime->onZygoteInit();
}virtual void onZygoteInit()
{
sp<ProcessState> proc = ProcessState::self();
if (proc->supportsProcesses()) {
LOGV("App process: starting thread pool.\n");
proc->startThreadPool(); //启动一个线程，用于binder通信
}
}调用invokeStaticMain函数：
private static void invokeStaticMain(String className, String[] argv)
throws ZygoteInit.MethodAndArgsCaller {
// We want to be fairly aggressive about heap utilization, to avoid
// holding on to a lot of memory that isn't needed.
VMRuntime.getRuntime().setTargetHeapUtilization(0.75f);
Class<?> cl;
try {
//com.android.server.SystemServer，通过反射加载SystemServer类
cl = Class.forName(className);
} 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 });//获取SystemServer类的main方法
} 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);
}
/*
* This throw gets caught in ZygoteInit.main(), which responds
* by invoking the exception's run() method. This arrangement
* clears up all the stack frames that were required in setting
* up the process. 抛出MethodAndArgsCaller异常，并在ZygoteInit.main()函数里铺货
*/
throw new ZygoteInit.MethodAndArgsCaller(m, argv);
}public static void main(String argv[]) {
try {
VMRuntime.getRuntime().setMinimumHeapSize(5 * 1024 * 1024);
// Start profiling the zygote initialization.
SamplingProfilerIntegration.start();
registerZygoteSocket();
EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START,
SystemClock.uptimeMillis());
preloadClasses();
//cacheRegisterMaps();
preloadResources();
EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END,
SystemClock.uptimeMillis());
// Finish profiling the zygote initialization.
SamplingProfilerIntegration.writeZygoteSnapshot();
// Do an initial gc to clean up after startup
gc();
// If requested, start system server directly from Zygote
if (argv.length != 2) {
throw new RuntimeException(argv[0] + USAGE_STRING);
}
if (argv[1].equals("true")) {
startSystemServer();
} else if (!argv[1].equals("false")) {
throw new RuntimeException(argv[0] + USAGE_STRING);
}
Log.i(TAG, "Accepting command socket connections");
if (ZYGOTE_FORK_MODE) {
runForkMode();
} else {
runSelectLoopMode();
}
closeServerSocket();
} catch (MethodAndArgsCaller caller) {
caller.run();
} catch (RuntimeException ex) {
Log.e(TAG, "Zygote died with exception", ex);
closeServerSocket();
throw ex;
}
}public void run() {
try {
//mMethod 是SystemServer类的main方法
mMethod.invoke(null, new Object[] { mArgs });
} catch (IllegalAccessException ex) {
throw new RuntimeException(ex);
} catch (InvocationTargetException ex) {
Throwable cause = ex.getCause();
if (cause instanceof RuntimeException) {
throw (RuntimeException) cause;
} else if (cause instanceof Error) {
throw (Error) cause;
}
throw new RuntimeException(ex);
}
}public static void main(String[] args) {
if (System.currentTimeMillis() < EARLIEST_SUPPORTED_TIME) {
// If a device's clock is before 1970 (before 0), a lot of
// APIs crash dealing with negative numbers, notably
// java.io.File#setLastModified, so instead we fake it and
// hope that time from cell towers or NTP fixes it
// shortly.
Slog.w(TAG, "System clock is before 1970; setting to 1970.");
SystemClock.setCurrentTimeMillis(EARLIEST_SUPPORTED_TIME);
}
if (SamplingProfilerIntegration.isEnabled()) {
//启动性能统计
SamplingProfilerIntegration.start();
timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
//输出性能统计结果
SamplingProfilerIntegration.writeSnapshot("system_server");
}
}, SNAPSHOT_INTERVAL, SNAPSHOT_INTERVAL);
}
// The system server has to run all of the time, so it needs to be
// as efficient as possible with its memory usage.
VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);
//加载android_servers.so库
System.loadLibrary("android_servers");
init1(args);
}抛出MethodAndArgsCaller异常会导致com.android.server.SystemServer类的main函数被调用。为什么采用这种方式来调用呢，读者可以自行研究！
native public static void init1(String[] args);static JNINativeMethod gMethods[] = {
/* name, signature, funcPtr */
{ "init1", "([Ljava/lang/String;)V", (void*) android_server_SystemServer_init1 },
};extern "C" int system_init();
static void android_server_SystemServer_init1(JNIEnv* env, jobject clazz)
{
system_init();
}extern "C" status_t system_init()
{
LOGI("Entered system_init()");
sp<ProcessState> proc(ProcessState::self());
//获取Service manager的远程调用接口
sp<IServiceManager> sm = defaultServiceManager();
LOGI("ServiceManager: %p\n", sm.get());
sp<GrimReaper> grim = new GrimReaper();
sm->asBinder()->linkToDeath(grim, grim.get(), 0);
char propBuf[PROPERTY_VALUE_MAX];
property_get("system_init.startsurfaceflinger", propBuf, "1");
//在SystemServer中启动各种服务
if (strcmp(propBuf, "1") == 0) {
// Start the SurfaceFlinger
SurfaceFlinger::instantiate();
}
// Start the sensor service
SensorService::instantiate();
// On the simulator, audioflinger et al don't get started the
// same way as on the device, and we need to start them here
if (!proc->supportsProcesses()) {
// Start the AudioFlinger
AudioFlinger::instantiate();
// Start the media playback service
MediaPlayerService::instantiate();
// Start the camera service
CameraService::instantiate();
// Start the audio policy service
AudioPolicyService::instantiate();
}
// And now start the Android runtime. We have to do this bit
// of nastiness because the Android runtime initialization requires
// some of the core system services to already be started.
// All other servers should just start the Android runtime at
// the beginning of their processes's main(), before calling
// the init function.
LOGI("System server: starting Android runtime.\n");
AndroidRuntime* runtime = AndroidRuntime::getRuntime();
LOGI("System server: starting Android services.\n");
//调用SystemServer.java 类中的init2函数
runtime->callStatic("com/android/server/SystemServer", "init2");
// If running in our own process, just go into the thread
// pool. Otherwise, call the initialization finished
// func to let this process continue its initilization.
//将SystemServer进程的主线程加入Binder通信中
if (proc->supportsProcesses()) {
LOGI("System server: entering thread pool.\n");
ProcessState::self()->startThreadPool();
IPCThreadState::self()->joinThreadPool();
LOGI("System server: exiting thread pool.\n");
}
return NO_ERROR;
}public static final void init2() {
Slog.i(TAG, "Entered the Android system server!");
Thread thr = new ServerThread();
thr.setName("android.server.ServerThread");
//启动一个线程
thr.start();
} @Override
public void run() {
EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_SYSTEM_RUN,
SystemClock.uptimeMillis());
Looper.prepare();
android.os.Process.setThreadPriority(
android.os.Process.THREAD_PRIORITY_FOREGROUND);
BinderInternal.disableBackgroundScheduling(true);
android.os.Process.setCanSelfBackground(false);
// Check whether we failed to shut down last time we tried.
{
final String shutdownAction = SystemProperties.get(
ShutdownThread.SHUTDOWN_ACTION_PROPERTY, "");
if (shutdownAction != null && shutdownAction.length() > 0) {
boolean reboot = (shutdownAction.charAt(0) == '1');
final String reason;
if (shutdownAction.length() > 1) {
reason = shutdownAction.substring(1, shutdownAction.length());
} else {
reason = null;
}
ShutdownThread.rebootOrShutdown(reboot, reason);
}
}
String factoryTestStr = SystemProperties.get("ro.factorytest");
int factoryTest = "".equals(factoryTestStr) ? SystemServer.FACTORY_TEST_OFF
: Integer.parseInt(factoryTestStr);
LightsService lights = null;
PowerManagerService power = null;
BatteryService battery = null;
ConnectivityService connectivity = null;
IPackageManager pm = null;
Context context = null;
WindowManagerService wm = null;
BluetoothService bluetooth = null;
BluetoothA2dpService bluetoothA2dp = null;
HeadsetObserver headset = null;
DockObserver dock = null;
UsbService usb = null;
UiModeManagerService uiMode = null;
RecognitionManagerService recognition = null;
ThrottleService throttle = null;
// Critical services...
try {
Slog.i(TAG, "Entropy Service");
ServiceManager.addService("entropy", new EntropyService());
Slog.i(TAG, "Power Manager");
power = new PowerManagerService();
ServiceManager.addService(Context.POWER_SERVICE, power);
Slog.i(TAG, "Activity Manager");
context = ActivityManagerService.main(factoryTest);
Slog.i(TAG, "Telephony Registry");
if (PhoneFactory.isMultiSim()) {
TelephonyRegistry[] telephonyRegistry = new TelephonyRegistry[PhoneFactory.getPhoneCount()];
for (int i = 0; i < PhoneFactory.getPhoneCount(); i++) {
telephonyRegistry[i] = new TelephonyRegistry(context, i);
ServiceManager.addService(PhoneFactory.getServiceName("telephony.registry", i),
telephonyRegistry[i]);
}
ServiceManager.addService("telephony.registry",
new CompositeTelephonyRegistry(context, telephonyRegistry));
} else {
ServiceManager.addService("telephony.registry",
new TelephonyRegistry(context, 0));
}
AttributeCache.init(context);
Slog.i(TAG, "Package Manager");
pm = PackageManagerService.main(context,
factoryTest != SystemServer.FACTORY_TEST_OFF);
ActivityManagerService.setSystemProcess();
mContentResolver = context.getContentResolver();
// The AccountManager must come before the ContentService
try {
Slog.i(TAG, "Account Manager");
ServiceManager.addService(Context.ACCOUNT_SERVICE,
new AccountManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Account Manager", e);
}
Slog.i(TAG, "Content Manager");
ContentService.main(context,
factoryTest == SystemServer.FACTORY_TEST_LOW_LEVEL);
Slog.i(TAG, "System Content Providers");
ActivityManagerService.installSystemProviders();
Slog.i(TAG, "Battery Service");
battery = new BatteryService(context);
ServiceManager.addService("battery", battery);
Slog.i(TAG, "Lights Service");
lights = new LightsService(context);
Slog.i(TAG, "Vibrator Service");
ServiceManager.addService("vibrator", new VibratorService(context));
// only initialize the power service after we have started the
// lights service, content providers and the battery service.
power.init(context, lights, ActivityManagerService.getDefault(), battery);
Slog.i(TAG, "Alarm Manager");
AlarmManagerService alarm = new AlarmManagerService(context);
ServiceManager.addService(Context.ALARM_SERVICE, alarm);
Slog.i(TAG, "Init Watchdog");
Watchdog.getInstance().init(context, battery, power, alarm,
ActivityManagerService.self());
Slog.i(TAG, "Window Manager");
wm = WindowManagerService.main(context, power,
factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL);
ServiceManager.addService(Context.WINDOW_SERVICE, wm);
((ActivityManagerService)ServiceManager.getService("activity"))
.setWindowManager(wm);
// Skip Bluetooth if we have an emulator kernel
// TODO: Use a more reliable check to see if this product should
// support Bluetooth - see bug 988521
if (SystemProperties.get("ro.kernel.qemu").equals("1")) {
Slog.i(TAG, "Registering null Bluetooth Service (emulator)");
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, null);
} else if (factoryTest == SystemServer.FACTORY_TEST_LOW_LEVEL) {
Slog.i(TAG, "Registering null Bluetooth Service (factory test)");
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, null);
} else {
Slog.i(TAG, "Bluetooth Service");
bluetooth = new BluetoothService(context);
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, bluetooth);
bluetooth.initAfterRegistration();
bluetoothA2dp = new BluetoothA2dpService(context, bluetooth);
ServiceManager.addService(BluetoothA2dpService.BLUETOOTH_A2DP_SERVICE,
bluetoothA2dp);
int bluetoothOn = Settings.Secure.getInt(mContentResolver,
Settings.Secure.BLUETOOTH_ON, 0);
if (bluetoothOn > 0) {
bluetooth.enable();
}
}
} catch (RuntimeException e) {
Slog.e("System", "Failure starting core service", e);
}
DevicePolicyManagerService devicePolicy = null;
StatusBarManagerService statusBar = null;
InputMethodManagerService imm = null;
AppWidgetService appWidget = null;
NotificationManagerService notification = null;
WallpaperManagerService wallpaper = null;
LocationManagerService location = null;
if (factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {
try {
Slog.i(TAG, "Device Policy");
devicePolicy = new DevicePolicyManagerService(context);
ServiceManager.addService(Context.DEVICE_POLICY_SERVICE, devicePolicy);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DevicePolicyService", e);
}
try {
Slog.i(TAG, "Status Bar");
statusBar = new StatusBarManagerService(context);
ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting StatusBarManagerService", e);
}
try {
Slog.i(TAG, "Clipboard Service");
ServiceManager.addService(Context.CLIPBOARD_SERVICE,
new ClipboardService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Clipboard Service", e);
}
try {
Slog.i(TAG, "Input Method Service");
imm = new InputMethodManagerService(context, statusBar);
ServiceManager.addService(Context.INPUT_METHOD_SERVICE, imm);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Input Manager Service", e);
}
try {
Slog.i(TAG, "NetStat Service");
ServiceManager.addService("netstat", new NetStatService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting NetStat Service", e);
}
try {
Slog.i(TAG, "NetworkManagement Service");
ServiceManager.addService(
Context.NETWORKMANAGEMENT_SERVICE,
NetworkManagementService.create(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting NetworkManagement Service", e);
}
try {
Slog.i(TAG, "Connectivity Service");
connectivity = ConnectivityService.getInstance(context);
ServiceManager.addService(Context.CONNECTIVITY_SERVICE, connectivity);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Connectivity Service", e);
}
try {
Slog.i(TAG, "Throttle Service");
throttle = new ThrottleService(context);
ServiceManager.addService(
Context.THROTTLE_SERVICE, throttle);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting ThrottleService", e);
}
try {
Slog.i(TAG, "Accessibility Manager");
ServiceManager.addService(Context.ACCESSIBILITY_SERVICE,
new AccessibilityManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Accessibility Manager", e);
}
try {
/*
* NotificationManagerService is dependant on MountService,
* (for media / usb notifications) so we must start MountService first.
*/
Slog.i(TAG, "Mount Service");
ServiceManager.addService("mount", new MountService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Mount Service", e);
}
try {
Slog.i(TAG, "Notification Manager");
notification = new NotificationManagerService(context, statusBar, lights);
ServiceManager.addService(Context.NOTIFICATION_SERVICE, notification);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Notification Manager", e);
}
try {
Slog.i(TAG, "Device Storage Monitor");
ServiceManager.addService(DeviceStorageMonitorService.SERVICE,
new DeviceStorageMonitorService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DeviceStorageMonitor service", e);
}
try {
Slog.i(TAG, "Location Manager");
location = new LocationManagerService(context);
ServiceManager.addService(Context.LOCATION_SERVICE, location);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Location Manager", e);
}
try {
Slog.i(TAG, "Search Service");
ServiceManager.addService(Context.SEARCH_SERVICE,
new SearchManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Search Service", e);
}
if (INCLUDE_DEMO) {
Slog.i(TAG, "Installing demo data...");
(new DemoThread(context)).start();
}
try {
Slog.i(TAG, "DropBox Service");
ServiceManager.addService(Context.DROPBOX_SERVICE,
new DropBoxManagerService(context, new File("/data/system/dropbox")));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DropBoxManagerService", e);
}
try {
Slog.i(TAG, "Wallpaper Service");
wallpaper = new WallpaperManagerService(context);
ServiceManager.addService(Context.WALLPAPER_SERVICE, wallpaper);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Wallpaper Service", e);
}
try {
Slog.i(TAG, "Audio Service");
ServiceManager.addService(Context.AUDIO_SERVICE, new AudioService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Audio Service", e);
}
try {
Slog.i(TAG, "Headset Observer");
// Listen for wired headset changes
headset = new HeadsetObserver(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting HeadsetObserver", e);
}
try {
Slog.i(TAG, "Dock Observer");
// Listen for dock station changes
dock = new DockObserver(context, power);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DockObserver", e);
}
try {
Slog.i(TAG, "USB Service");
// Listen for USB changes
usb = new UsbService(context);
ServiceManager.addService(Context.USB_SERVICE, usb);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting UsbService", e);
}
try {
Slog.i(TAG, "UI Mode Manager Service");
// Listen for UI mode changes
uiMode = new UiModeManagerService(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting UiModeManagerService", e);
}
try {
Slog.i(TAG, "Backup Service");
ServiceManager.addService(Context.BACKUP_SERVICE,
new BackupManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Backup Service", e);
}
try {
Slog.i(TAG, "AppWidget Service");
appWidget = new AppWidgetService(context);
ServiceManager.addService(Context.APPWIDGET_SERVICE, appWidget);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting AppWidget Service", e);
}
try {
Slog.i(TAG, "Recognition Service");
recognition = new RecognitionManagerService(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Recognition Service", e);
}
try {
Slog.i(TAG, "DiskStats Service");
ServiceManager.addService("diskstats", new DiskStatsService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DiskStats Service", e);
}
try {
Slog.i(TAG, "AnotherWatchdog Service");
ServiceManager.addService("another_watchdog", new AnotherWatchdogService());
} catch (Throwable e) {
Slog.e(TAG, "Failure starting AnotherWatchdog Service", e);
}
}
// make sure the ADB_ENABLED setting value matches the secure property value
Settings.Secure.putInt(mContentResolver, Settings.Secure.ADB_ENABLED,
"1".equals(SystemProperties.get("persist.service.adb.enable")) ? 1 : 0);
// register observer to listen for settings changes
mContentResolver.registerContentObserver(Settings.Secure.getUriFor(Settings.Secure.ADB_ENABLED),
false, new AdbSettingsObserver());
// Before things start rolling, be sure we have decided whether
// we are in safe mode.
final boolean safeMode = wm.detectSafeMode();
if (safeMode) {
try {
ActivityManagerNative.getDefault().enterSafeMode();
// Post the safe mode state in the Zygote class
Zygote.systemInSafeMode = true;
// Disable the JIT for the system_server process
VMRuntime.getRuntime().disableJitCompilation();
} catch (RemoteException e) {
}
} else {
// Enable the JIT for the system_server process
VMRuntime.getRuntime().startJitCompilation();
}
// It is now time to start up the app processes...
if (devicePolicy != null) {
devicePolicy.systemReady();
}
if (notification != null) {
notification.systemReady();
}
if (statusBar != null) {
statusBar.systemReady();
}
wm.systemReady();
power.systemReady();
try {
pm.systemReady();
} catch (RemoteException e) {
}
// These are needed to propagate to the runnable below.
final StatusBarManagerService statusBarF = statusBar;
final BatteryService batteryF = battery;
final ConnectivityService connectivityF = connectivity;
final DockObserver dockF = dock;
final UsbService usbF = usb;
final ThrottleService throttleF = throttle;
final UiModeManagerService uiModeF = uiMode;
final AppWidgetService appWidgetF = appWidget;
final WallpaperManagerService wallpaperF = wallpaper;
final InputMethodManagerService immF = imm;
final RecognitionManagerService recognitionF = recognition;
final LocationManagerService locationF = location;
// We now tell the activity manager it is okay to run third party
// code. It will call back into us once it has gotten to the state
// where third party code can really run (but before it has actually
// started launching the initial applications), for us to complete our
// initialization.
((ActivityManagerService)ActivityManagerNative.getDefault())
.systemReady(new Runnable() {
public void run() {
Slog.i(TAG, "Making services ready");
if (statusBarF != null) statusBarF.systemReady2();
if (batteryF != null) batteryF.systemReady();
if (connectivityF != null) connectivityF.systemReady();
if (dockF != null) dockF.systemReady();
if (usbF != null) usbF.systemReady();
if (uiModeF != null) uiModeF.systemReady();
if (recognitionF != null) recognitionF.systemReady();
Watchdog.getInstance().start();
// It is now okay to let the various system services start their
// third party code...
if (appWidgetF != null) appWidgetF.systemReady(safeMode);
if (wallpaperF != null) wallpaperF.systemReady();
if (immF != null) immF.systemReady();
if (locationF != null) locationF.systemReady();
if (throttleF != null) throttleF.systemReady();
}
});
(new Thread(new WakelockMonitor(power))).start();
// For debug builds, log event loop stalls to dropbox for analysis.
if (StrictMode.conditionallyEnableDebugLogging()) {
Slog.i(TAG, "Enabled StrictMode for system server main thread.");
}
Looper.loop();
Slog.d(TAG, "System ServerThread is exiting!");
}
在run函数中启动Java中的各种Service。至此SystemServer进程启动过程分析完毕！启动过程序列图如下所示：
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