Android系统SystemServer进程启动过程源码分析

╰半橙微兮° 2022-08-06 05:17 312阅读 0赞

frameworks/base/core/java/com/android/internal/os/ZygoteInit.java文件中：

Step1、startSystemServer函数

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1.  **public****class** ZygoteInit \{ 
2.   ...... 
3.  
4.  **private****static****boolean** startSystemServer() 
5.  **throws** MethodAndArgsCaller, RuntimeException \{ 
6.  /\* Hardcoded command line to start the system server \*/
7.   String args\[\] = \{ 
8.  "--setuid=1000", 
9.  "--setgid=1000", 
10. "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,3001,3002,3003", 
11. "--capabilities=130104352,130104352", 
12. "--runtime-init", 
13. "--nice-name=system\_server", 
14. "com.android.server.SystemServer", 
15.  \}; 
16.  ZygoteConnection.Arguments parsedArgs = **null**; 
17. 
18. **int** pid; 
19. 
20. **try** \{ 
21.  parsedArgs = **new** ZygoteConnection.Arguments(args); 
22. 
23.  ...... 
24. 
25. /\* Request to fork the system server process \*/
26. //startSystemServer()调用Zygote的native方法 forkSystemServer(),java端的Zygote的准备工作就结束了,接下来就交给C/C++端的Zygote来执行fork任务了，在/dalvik/vm/native/dalvik\_system\_Zygote.c 中，Dalvik\_dalvik\_system\_Zygote\_forkSystemServer函数中（自己去看源码）
27. 这个里面的fork进程主要是使用linux的fork进程  
    
28. //Zygote进程通过Zygote.forkSystemServer函数来创建一个新的进程来启动SystemServer组件
29.  pid = Zygote.forkSystemServer( 
30.  parsedArgs.uid, parsedArgs.gid, 
31.  parsedArgs.gids, debugFlags, **null**, 
32.  parsedArgs.permittedCapabilities, 
33.  parsedArgs.effectiveCapabilities); 
34.  \} **catch** (IllegalArgumentException ex) \{ 
35.  ...... 
36.  \} 
37. 
38. /\* For child process \*/
39. //新创建的子进程会执行handleSystemServerProcess函数。
40. **if** (pid == 0) \{ 
41.  handleSystemServerProcess(parsedArgs); 
42.  \} 
43. 
44. **return****true**; 
45.  \} 
46. 
47.  ...... 
48. \}

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1.  **public****class** ZygoteInit \{ 
2.   ...... 
3.  
4.  **private****static****void** handleSystemServerProcess( 
5.   ZygoteConnection.Arguments parsedArgs) 
6.  **throws** ZygoteInit.MethodAndArgsCaller \{ 
7.    
    
8.  //Zygote进程创建的子进程会继承Zygote进程创建的Socket文件描述符，而这里的子进程又不会用到它，因此，这里就调用closeServerSocket函数来关闭它。
9.   closeServerSocket(); 
10. 
11. /\*
12.  \* Pass the remaining arguments to SystemServer.
13.  \* "--nice-name=system\_server com.android.server.SystemServer"
14.  \*/
15. // 进一步执行启动SystemServer组件的操作
16.  RuntimeInit.zygoteInit(parsedArgs.remainingArgs); 
17. /\* should never reach here \*/
18.  \} 
19. 
20.  ...... 
21. \}

函数定义在frameworks/base/core/java/com/android/internal/os/RuntimeInit.java文件中：

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1.  **public****class** RuntimeInit \{ 
2.   ...... 
3.  
4.  **public****static****final****void** zygoteInit(String\[\] argv) 
5.  **throws** ZygoteInit.MethodAndArgsCaller \{ 
6.   ...... 
7.  //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
8.  //函数zygoteInitNative是一个Native函数，实现在frameworks/base/core/jni/AndroidRuntime.cpp文件中，这里我们就不再细看了
9.   zygoteInitNative(); 
10. 
11.  ...... 
12. 
13. //调用上面传进来的com.android.server.SystemServer类的main函数。
14. // Remaining arguments are passed to the start class's static main 
15. 
16.  String startClass = argv\[curArg++\]; 
17.  String\[\] startArgs = **new** String\[argv.length - curArg\]; 
18. 
19.  System.arraycopy(argv, curArg, startArgs, 0, startArgs.length); 
20.  invokeStaticMain(startClass, startArgs); 
21.  \} 
22. 
23.  ...... 
24. \}

这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中：

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1.  **public****class** SystemServer 
2.  \{ 
3.   ...... 
4.  
5.  **native****public****static****void** init1(String\[\] args); 
6.  
7.   ...... 
8.  
9.  **public****static****void** main(String\[\] args) \{ 
10.  ...... 
11. 
12.  init1(args);//首先会执行JNI方法init1，然后init1会调用这里的init2函数
13. 
14.  ...... 
15.  \} 
16. 
17. **public****static****final****void** init2() \{ 
18.  Slog.i(TAG, "Entered the Android system server!"); 
19. //创建一个ServerThread线程对象来执行一些系统关键服务的启动操作，
20. //例如 PackageManagerService和ActivityManagerService
21.  Thread thr = **new** ServerThread(); 
22.  thr.setName("android.server.ServerThread"); 
23.  thr.start(); 
24.  \} 
25. 
26.  ...... 
27. \}

Step2 、 frameworks/base/services/jni/com\_android\_server\_SystemServer.cpp文件中：

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1.  **namespace** android \{ 
2.  
3.  **extern**"C"**int** system\_init(); 
4.  
5.  **static****void** android\_server\_SystemServer\_init1(JNIEnv\* env, jobject clazz) 
6.  \{ 
7.   system\_init(); 
8.  \} 
9.  
10. /\*
11.  \* JNI registration.
12.  \*/
13. **static** JNINativeMethod gMethods\[\] = \{ 
14. /\* name, signature, funcPtr \*/
15.  \{ "init1", "(\[Ljava/lang/String;)V", (**void**\*) android\_server\_SystemServer\_init1 \}, 
16. \}; 
17. 
18. **int** register\_android\_server\_SystemServer(JNIEnv\* env) 
19. \{ 
20. **return** jniRegisterNativeMethods(env, "com/android/server/SystemServer", 
21.  gMethods, NELEM(gMethods)); 
22. \} 
23. 
24. \}; // namespace android

函数system\_init实现在libsystem\_server库中，源代码位于frameworks/base/cmds/system\_server/library/system\_init.cpp文件中：

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1.  **extern**"C" status\_t system\_init() 
2.  \{ 
3.   LOGI("Entered system\_init()"); 
4.  
5.   sp<ProcessState> proc(ProcessState::self()); 
6.  
7.   sp<IServiceManager> sm = defaultServiceManager(); 
8.   LOGI("ServiceManager: %p\\n", sm.get()); 
9.  
10.  sp<GrimReaper> grim = **new** GrimReaper(); 
11.  sm->asBinder()->linkToDeath(grim, grim.get(), 0); 
12. 
13. **char** propBuf\[PROPERTY\_VALUE\_MAX\]; 
14.  property\_get("system\_init.startsurfaceflinger", propBuf, "1"); 
15. **if** (strcmp(propBuf, "1") == 0) \{ 
16. // Start the SurfaceFlinger
17.  SurfaceFlinger::instantiate(); 
18.  \} 
19. 
20. // Start the sensor service
21.  SensorService::instantiate(); 
22. 
23. // On the simulator, audioflinger et al don't get started the
24. // same way as on the device, and we need to start them here
25. **if** (!proc->supportsProcesses()) \{ 
26. 
27. // Start the AudioFlinger
28.  AudioFlinger::instantiate(); 
29. 
30. // Start the media playback service
31.  MediaPlayerService::instantiate(); 
32. 
33. // Start the camera service
34.  CameraService::instantiate(); 
35. 
36. // Start the audio policy service
37.  AudioPolicyService::instantiate(); 
38.  \} 
39. 
40. // And now start the Android runtime. We have to do this bit
41. // of nastiness because the Android runtime initialization requires
42. // some of the core system services to already be started.
43. // All other servers should just start the Android runtime at
44. // the beginning of their processes's main(), before calling
45. // the init function.
46.  LOGI("System server: starting Android runtime.\\n"); 
47. 
48.  AndroidRuntime\* runtime = AndroidRuntime::getRuntime(); 
49. 
50.  LOGI("System server: starting Android services.\\n"); 
51.  runtime->callStatic("com/android/server/SystemServer", "init2"); 
52. 
53. // If running in our own process, just go into the thread
54. // pool. Otherwise, call the initialization finished
55. // func to let this process continue its initilization.
56. **if** (proc->supportsProcesses()) \{ 
57.  LOGI("System server: entering thread pool.\\n"); 
58.  ProcessState::self()->startThreadPool(); 
59.  IPCThreadState::self()->joinThreadPool(); 
60.  LOGI("System server: exiting thread pool.\\n"); 
61.  \} 
62. 
63. **return** NO\_ERROR; 
64. \}

这个函数首先会初始化SurfaceFlinger、SensorService、AudioFlinger、MediaPlayerService、CameraService和AudioPolicyService这几个服务，然后就通过系统全局唯一的AndroidRuntime实例变量runtime的callStatic来调用SystemServer的init2函数了。

这个函数定义在frameworks/base/core/jni/AndroidRuntime.cpp文件中：

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1.  /\*
2.  \* Call a static Java Programming Language function that takes no arguments and returns void.
3.  \*/
4.  status\_t AndroidRuntime::callStatic(**const****char**\* className, **const****char**\* methodName) 
5.  \{ 
6.   JNIEnv\* env; 
7.   jclass clazz; 
8.   jmethodID methodId; 
9.  
10.  env = getJNIEnv(); 
11. **if** (env == NULL) 
12. **return** UNKNOWN\_ERROR; 
13. 
14.  clazz = findClass(env, className); 
15. **if** (clazz == NULL) \{ 
16.  LOGE("ERROR: could not find class '%s'\\n", className); 
17. **return** UNKNOWN\_ERROR; 
18.  \} 
19.  methodId = env->GetStaticMethodID(clazz, methodName, "()V"); 
20. **if** (methodId == NULL) \{ 
21.  LOGE("ERROR: could not find method %s.%s\\n", className, methodName); 
22. **return** UNKNOWN\_ERROR; 
23.  \} 
24. 
25.  env->CallStaticVoidMethod(clazz, methodId); 
26. 
27. **return** NO\_ERROR; 
28. \}

这个函数调用由参数className指定的java类的静态成员函数，这个静态成员函数是由参数methodName指定的。上面传进来的参数className的值为"com/android/server/SystemServer"，而参数methodName的值为"init2"，因此，接下来就会调用SystemServer类的init2函数了。

Step3、

这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中：

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1.  **class** ServerThread **extends** Thread \{ 
2.  **private****static****final** String TAG = "SystemServer"; 
3.  **private****final****static****boolean** INCLUDE\_DEMO = **false**; 
4.  
5.  **private****static****final****int** LOG\_BOOT\_PROGRESS\_SYSTEM\_RUN = 3010; 
6.  
7.  **private** ContentResolver mContentResolver; 
8.  
9.  **private****class** AdbSettingsObserver **extends** ContentObserver \{ 
10. **public** AdbSettingsObserver() \{ 
11. **super**(**null**); 
12.  \} 
13. @Override
14. **public****void** onChange(**boolean** selfChange) \{ 
15. **boolean** enableAdb = (Settings.Secure.getInt(mContentResolver, 
16.  Settings.Secure.ADB\_ENABLED, 0) > 0); 
17. // setting this secure property will start or stop adbd
18.  SystemProperties.set("persist.service.adb.enable", enableAdb ? "1" : "0"); 
19.  \} 
20.  \} 
21. 
22. @Override
23. **public****void** run() \{ 
24.  EventLog.writeEvent(EventLogTags.BOOT\_PROGRESS\_SYSTEM\_RUN, 
25.  SystemClock.uptimeMillis()); 
26. 
27.  Looper.prepare(); 
28. 
29.  android.os.Process.setThreadPriority( 
30.  android.os.Process.THREAD\_PRIORITY\_FOREGROUND); 
31. 
32.  BinderInternal.disableBackgroundScheduling(**true**); 
33.  android.os.Process.setCanSelfBackground(**false**); 
34. 
35. // Check whether we failed to shut down last time we tried.
36.  \{ 
37. **final** String shutdownAction = SystemProperties.get( 
38.  ShutdownThread.SHUTDOWN\_ACTION\_PROPERTY, ""); 
39. **if** (shutdownAction != **null** && shutdownAction.length() > 0) \{ 
40. **boolean** reboot = (shutdownAction.charAt(0) == '1'); 
41. 
42. **final** String reason; 
43. **if** (shutdownAction.length() > 1) \{ 
44.  reason = shutdownAction.substring(1, shutdownAction.length()); 
45.  \} **else** \{ 
46.  reason = **null**; 
47.  \} 
48. 
49.  ShutdownThread.rebootOrShutdown(reboot, reason); 
50.  \} 
51.  \} 
52. 
53.  String factoryTestStr = SystemProperties.get("ro.factorytest"); 
54. **int** factoryTest = "".equals(factoryTestStr) ? SystemServer.FACTORY\_TEST\_OFF 
55.  : Integer.parseInt(factoryTestStr); 
56. 
57.  LightsService lights = **null**; 
58.  PowerManagerService power = **null**; 
59.  BatteryService battery = **null**; 
60.  ConnectivityService connectivity = **null**; 
61.  IPackageManager pm = **null**; 
62.  Context context = **null**; 
63.  WindowManagerService wm = **null**; 
64.  BluetoothService bluetooth = **null**; 
65.  BluetoothA2dpService bluetoothA2dp = **null**; 
66.  HeadsetObserver headset = **null**; 
67.  DockObserver dock = **null**; 
68.  UsbService usb = **null**; 
69.  UiModeManagerService uiMode = **null**; 
70.  RecognitionManagerService recognition = **null**; 
71.  ThrottleService throttle = **null**; 
72. 
73. // Critical services...
74. **try** \{  
    //EntropyService服务  
    
75.  Slog.i(TAG, "Entropy Service"); 
76.  ServiceManager.addService("entropy", **new** EntropyService()); 
77. 
78. //电源管理服务
79.  Slog.i(TAG, "Power Manager"); 
80.  power = **new** PowerManagerService(); 
81.  ServiceManager.addService(Context.POWER\_SERVICE, power); 
82. 
83. //ActivityManagerService服务
84.  Slog.i(TAG, "Activity Manager"); 
85.  context = ActivityManagerService.main(factoryTest); 
86.   
    
87. //TelephonyRegistry服务
88.  Slog.i(TAG, "Telephony Registry"); 
89.  ServiceManager.addService("telephony.registry", **new** TelephonyRegistry(context)); 
90. 
91.  AttributeCache.init(context); 
92. 
93. //PackageManagerService包管理服务
94.  Slog.i(TAG, "Package Manager"); 
95.  pm = PackageManagerService.main(context, 
96.  factoryTest != SystemServer.FACTORY\_TEST\_OFF); 
97. 
98.  ActivityManagerService.setSystemProcess(); 
99. 
100. //内容解决者
101.  mContentResolver = context.getContentResolver(); 
102.   
    
103. //账号、密码、权限管理服务
104. // The AccountManager must come before the ContentService
105. **try** \{ 
106.  Slog.i(TAG, "Account Manager"); 
107.  ServiceManager.addService(Context.ACCOUNT\_SERVICE, 
108. **new** AccountManagerService(context)); 
109.  \} **catch** (Throwable e) \{ 
110.  Slog.e(TAG, "Failure starting Account Manager", e); 
111.  \} 
112. 
113. //内容服务
114.  Slog.i(TAG, "Content Manager"); 
115.  ContentService.main(context, 
116.  factoryTest == SystemServer.FACTORY\_TEST\_LOW\_LEVEL); 
117.   
    
118. //内容提供者 
119.  Slog.i(TAG, "System Content Providers"); 
120.  ActivityManagerService.installSystemProviders(); 
121. 
122. //电池服务
123.  Slog.i(TAG, "Battery Service"); 
124.  battery = **new** BatteryService(context); 
125.  ServiceManager.addService("battery", battery); 
126. 
127. //亮屏服务
128.  Slog.i(TAG, "Lights Service"); 
129.  lights = **new** LightsService(context); 
130. 
131. //手机震动服务
132.  Slog.i(TAG, "Vibrator Service"); 
133.  ServiceManager.addService("vibrator", **new** VibratorService(context)); 
134. 
135. //在开始亮屏服务、内容提供者服务、电池服务启动后，才初始化电源服务
136. // only initialize the power service after we have started the
137. // lights service, content providers and the battery service.
138.  power.init(context, lights, ActivityManagerService.getDefault(), battery); 
139. 
140. //闹钟服务
141.  Slog.i(TAG, "Alarm Manager"); 
142.  AlarmManagerService alarm = **new** AlarmManagerService(context); 
143.  ServiceManager.addService(Context.ALARM\_SERVICE, alarm); 
144. 
145. //初始化看门狗
146.  Slog.i(TAG, "Init Watchdog"); 
147.  Watchdog.getInstance().init(context, battery, power, alarm, 
148.  ActivityManagerService.self()); 
149. 
150. //窗口管理服务
151.  Slog.i(TAG, "Window Manager"); 
152.  wm = WindowManagerService.main(context, power, 
153.  factoryTest != SystemServer.FACTORY\_TEST\_LOW\_LEVEL); 
154.  ServiceManager.addService(Context.WINDOW\_SERVICE, wm); 
155. 
156.  ((ActivityManagerService)ServiceManager.getService("activity")) 
157.  .setWindowManager(wm); 
158.   
    
159. //蓝牙服务 
160. // Skip Bluetooth if we have an emulator kernel
161. // TODO: Use a more reliable check to see if this product should
162. // support Bluetooth - see bug 988521
163. **if** (SystemProperties.get("ro.kernel.qemu").equals("1")) \{ 
164.  Slog.i(TAG, "Registering null Bluetooth Service (emulator)"); 
165.  ServiceManager.addService(BluetoothAdapter.BLUETOOTH\_SERVICE, **null**); 
166.  \} **else****if** (factoryTest == SystemServer.FACTORY\_TEST\_LOW\_LEVEL) \{ 
167.  Slog.i(TAG, "Registering null Bluetooth Service (factory test)"); 
168.  ServiceManager.addService(BluetoothAdapter.BLUETOOTH\_SERVICE, **null**); 
169.  \} **else** \{ 
170.  Slog.i(TAG, "Bluetooth Service"); 
171.  bluetooth = **new** BluetoothService(context); 
172.  ServiceManager.addService(BluetoothAdapter.BLUETOOTH\_SERVICE, bluetooth); 
173.  bluetooth.initAfterRegistration(); 
174.  bluetoothA2dp = **new** BluetoothA2dpService(context, bluetooth); 
175.  ServiceManager.addService(BluetoothA2dpService.BLUETOOTH\_A2DP\_SERVICE, 
176.  bluetoothA2dp); 
177. 
178. **int** bluetoothOn = Settings.Secure.getInt(mContentResolver, 
179.  Settings.Secure.BLUETOOTH\_ON, 0); 
180. **if** (bluetoothOn > 0) \{ 
181.  bluetooth.enable(); 
182.  \} 
183.  \} 
184. 
185.  \} **catch** (RuntimeException e) \{ 
186.  Slog.e("System", "Failure starting core service", e); 
187.  \} 
188. 
189.  DevicePolicyManagerService devicePolicy = **null**; 
190.  StatusBarManagerService statusBar = **null**; 
191.  InputMethodManagerService imm = **null**; 
192.  AppWidgetService appWidget = **null**; 
193.  NotificationManagerService notification = **null**; 
194.  WallpaperManagerService wallpaper = **null**; 
195.  LocationManagerService location = **null**; 
196. 
197. **if** (factoryTest != SystemServer.FACTORY\_TEST\_LOW\_LEVEL) \{ 
198. **try** \{ 
199.  Slog.i(TAG, "Device Policy"); 
200.  devicePolicy = **new** DevicePolicyManagerService(context); 
201.  ServiceManager.addService(Context.DEVICE\_POLICY\_SERVICE, devicePolicy); 
202.  \} **catch** (Throwable e) \{ 
203.  Slog.e(TAG, "Failure starting DevicePolicyService", e); 
204.  \} 
205. 
206. **try** \{ 
207.  Slog.i(TAG, "Status Bar"); 
208.  statusBar = **new** StatusBarManagerService(context); 
209.  ServiceManager.addService(Context.STATUS\_BAR\_SERVICE, statusBar); 
210.  \} **catch** (Throwable e) \{ 
211.  Slog.e(TAG, "Failure starting StatusBarManagerService", e); 
212.  \} 
213. 
214. **try** \{ 
215.  Slog.i(TAG, "Clipboard Service"); 
216.  ServiceManager.addService(Context.CLIPBOARD\_SERVICE, 
217. **new** ClipboardService(context)); 
218.  \} **catch** (Throwable e) \{ 
219.  Slog.e(TAG, "Failure starting Clipboard Service", e); 
220.  \} 
221.  //输入法管理服务
222. **try** \{ 
223.  Slog.i(TAG, "Input Method Service"); 
224.  imm = **new** InputMethodManagerService(context, statusBar); 
225.  ServiceManager.addService(Context.INPUT\_METHOD\_SERVICE, imm); 
226.  \} **catch** (Throwable e) \{ 
227.  Slog.e(TAG, "Failure starting Input Manager Service", e); 
228.  \} 
229. 
230. //网络状态服务
231. **try** \{ 
232.  Slog.i(TAG, "NetStat Service"); 
233.  ServiceManager.addService("netstat", **new** NetStatService(context)); 
234.  \} **catch** (Throwable e) \{ 
235.  Slog.e(TAG, "Failure starting NetStat Service", e); 
236.  \} 
237. 
238. //网络管理服务
239. **try** \{ 
240.  Slog.i(TAG, "NetworkManagement Service"); 
241.  ServiceManager.addService( 
242.  Context.NETWORKMANAGEMENT\_SERVICE, 
243.  NetworkManagementService.create(context)); 
244.  \} **catch** (Throwable e) \{ 
245.  Slog.e(TAG, "Failure starting NetworkManagement Service", e); 
246.  \} 
247. 
248. //网络连接服务 
249. **try** \{ 
250.  Slog.i(TAG, "Connectivity Service"); 
251.  connectivity = ConnectivityService.getInstance(context); 
252.  ServiceManager.addService(Context.CONNECTIVITY\_SERVICE, connectivity); 
253.  \} **catch** (Throwable e) \{ 
254.  Slog.e(TAG, "Failure starting Connectivity Service", e); 
255.  \} 
256. 
257. //节流阀控制，提高modem使用效率，避免数据过大或过小情况下不必要的重复连接和断开。
258. **try** \{ 
259.  Slog.i(TAG, "Throttle Service"); 
260.  throttle = **new** ThrottleService(context); 
261.  ServiceManager.addService( 
262.  Context.THROTTLE\_SERVICE, throttle); 
263.  \} **catch** (Throwable e) \{ 
264.  Slog.e(TAG, "Failure starting ThrottleService", e); 
265.  \} 
266.   
    
267. //可访问管理服务 
268. **try** \{ 
269.  Slog.i(TAG, "Accessibility Manager"); 
270.  ServiceManager.addService(Context.ACCESSIBILITY\_SERVICE, 
271. **new** AccessibilityManagerService(context)); 
272.  \} **catch** (Throwable e) \{ 
273.  Slog.e(TAG, "Failure starting Accessibility Manager", e); 
274.  \} 
275. 
276. //磁盘加载服务(sd卡等)
277. **try** \{ 
278. /\*
279.  \* NotificationManagerService is dependant on MountService,
280.  \* (for media / usb notifications) so we must start MountService first.
281.  \*/
282.  Slog.i(TAG, "Mount Service"); 
283.  ServiceManager.addService("mount", **new** MountService(context)); 
284.  \} **catch** (Throwable e) \{ 
285.  Slog.e(TAG, "Failure starting Mount Service", e); 
286.  \} 
287. 
288. //通知管理服务
289. **try** \{ 
290.  Slog.i(TAG, "Notification Manager"); 
291.  notification = **new** NotificationManagerService(context, statusBar, lights); 
292.  ServiceManager.addService(Context.NOTIFICATION\_SERVICE, notification); 
293.  \} **catch** (Throwable e) \{ 
294.  Slog.e(TAG, "Failure starting Notification Manager", e); 
295.  \} 
296. 
297. //监控磁盘空间服务
298. **try** \{ 
299.  Slog.i(TAG, "Device Storage Monitor"); 
300.  ServiceManager.addService(DeviceStorageMonitorService.SERVICE, 
301. **new** DeviceStorageMonitorService(context)); 
302.  \} **catch** (Throwable e) \{ 
303.  Slog.e(TAG, "Failure starting DeviceStorageMonitor service", e); 
304.  \} 
305. 
306. //定位管理服务
307. **try** \{ 
308.  Slog.i(TAG, "Location Manager"); 
309.  location = **new** LocationManagerService(context); 
310.  ServiceManager.addService(Context.LOCATION\_SERVICE, location); 
311.  \} **catch** (Throwable e) \{ 
312.  Slog.e(TAG, "Failure starting Location Manager", e); 
313.  \} 
314. 
315. //搜索管理服务 
316. **try** \{ 
317.  Slog.i(TAG, "Search Service"); 
318.  ServiceManager.addService(Context.SEARCH\_SERVICE, 
319. **new** SearchManagerService(context)); 
320.  \} **catch** (Throwable e) \{ 
321.  Slog.e(TAG, "Failure starting Search Service", e); 
322.  \} 
323. 
324. //开启守护进程 
325. **if** (INCLUDE\_DEMO) \{ 
326.  Slog.i(TAG, "Installing demo data..."); 
327.  (**new** DemoThread(context)).start(); 
328.  \} 
329. 
330. //DropBoxManagerService用于生成和管理系统运行时的一些日志文件。这些日志文件大多记录的是系统或某个应用程序出错时的信息。
331. **try** \{ 
332.  Slog.i(TAG, "DropBox Service"); 
333.  ServiceManager.addService(Context.DROPBOX\_SERVICE, 
334. **new** DropBoxManagerService(context, **new** File("/data/system/dropbox"))); 
335.  \} **catch** (Throwable e) \{ 
336.  Slog.e(TAG, "Failure starting DropBoxManagerService", e); 
337.  \} 
338. 
339. //壁纸管理服务 
340. **try** \{ 
341.  Slog.i(TAG, "Wallpaper Service"); 
342.  wallpaper = **new** WallpaperManagerService(context); 
343.  ServiceManager.addService(Context.WALLPAPER\_SERVICE, wallpaper); 
344.  \} **catch** (Throwable e) \{ 
345.  Slog.e(TAG, "Failure starting Wallpaper Service", e); 
346.  \} 
347. 
348. //音频服务 
349. **try** \{ 
350.  Slog.i(TAG, "Audio Service"); 
351.  ServiceManager.addService(Context.AUDIO\_SERVICE, **new** AudioService(context)); 
352.  \} **catch** (Throwable e) \{ 
353.  Slog.e(TAG, "Failure starting Audio Service", e); 
354.  \} 
355.   
    
356. //HeadsetObserver耳机监听
357. **try** \{ 
358.  Slog.i(TAG, "Headset Observer"); 
359. // Listen for wired headset changes
360.  headset = **new** HeadsetObserver(context); 
361.  \} **catch** (Throwable e) \{ 
362.  Slog.e(TAG, "Failure starting HeadsetObserver", e); 
363.  \} 
364.   
    
365. //DockObserver手机亮度的监听
366. **try** \{ 
367.  Slog.i(TAG, "Dock Observer"); 
368. // Listen for dock station changes
369.  dock = **new** DockObserver(context, power); 
370.  \} **catch** (Throwable e) \{ 
371.  Slog.e(TAG, "Failure starting DockObserver", e); 
372.  \} 
373. 
374. //usb服务 
375. **try** \{ 
376.  Slog.i(TAG, "USB Service"); 
377. // Listen for USB changes
378.  usb = **new** UsbService(context); 
379.  ServiceManager.addService(Context.USB\_SERVICE, usb); 
380.  \} **catch** (Throwable e) \{ 
381.  Slog.e(TAG, "Failure starting UsbService", e); 
382.  \} 
383. 
384. //ui模式管理服务 
385. **try** \{ 
386.  Slog.i(TAG, "UI Mode Manager Service"); 
387. // Listen for UI mode changes
388.  uiMode = **new** UiModeManagerService(context); 
389.  \} **catch** (Throwable e) \{ 
390.  Slog.e(TAG, "Failure starting UiModeManagerService", e); 
391.  \} 
392.   
    
393. //备份管理服务 
394. **try** \{ 
395.  Slog.i(TAG, "Backup Service"); 
396.  ServiceManager.addService(Context.BACKUP\_SERVICE, 
397. **new** BackupManagerService(context)); 
398.  \} **catch** (Throwable e) \{ 
399.  Slog.e(TAG, "Failure starting Backup Service", e); 
400.  \} 
401. 
402. //appWidget服务
403. **try** \{ 
404.  Slog.i(TAG, "AppWidget Service"); 
405.  appWidget = **new** AppWidgetService(context); 
406.  ServiceManager.addService(Context.APPWIDGET\_SERVICE, appWidget); 
407.  \} **catch** (Throwable e) \{ 
408.  Slog.e(TAG, "Failure starting AppWidget Service", e); 
409.  \} 
410. 
411. **try** \{ 
412.  Slog.i(TAG, "Recognition Service"); 
413.  recognition = **new** RecognitionManagerService(context); 
414.  \} **catch** (Throwable e) \{ 
415.  Slog.e(TAG, "Failure starting Recognition Service", e); 
416.  \} 
417. 
418. **try** \{ 
419.  Slog.i(TAG, "DiskStats Service"); 
420.  ServiceManager.addService("diskstats", **new** DiskStatsService(context)); 
421.  \} **catch** (Throwable e) \{ 
422.  Slog.e(TAG, "Failure starting DiskStats Service", e); 
423.  \} 
424.  \} 
425. 
426. // make sure the ADB\_ENABLED setting value matches the secure property value
427.  Settings.Secure.putInt(mContentResolver, Settings.Secure.ADB\_ENABLED, 
428. "1".equals(SystemProperties.get("persist.service.adb.enable")) ? 1 : 0); 
429. 
430. // register observer to listen for settings changes
431.  mContentResolver.registerContentObserver(Settings.Secure.getUriFor(Settings.Secure.ADB\_ENABLED), 
432. **false**, **new** AdbSettingsObserver()); 
433. 
434. // Before things start rolling, be sure we have decided whether
435. // we are in safe mode.
436. **final****boolean** safeMode = wm.detectSafeMode(); 
437. **if** (safeMode) \{ 
438. **try** \{ 
439.  ActivityManagerNative.getDefault().enterSafeMode(); 
440. // Post the safe mode state in the Zygote class
441.  Zygote.systemInSafeMode = **true**; 
442. // Disable the JIT for the system\_server process
443.  VMRuntime.getRuntime().disableJitCompilation(); 
444.  \} **catch** (RemoteException e) \{ 
445.  \} 
446.  \} **else** \{ 
447. // Enable the JIT for the system\_server process
448.  VMRuntime.getRuntime().startJitCompilation(); 
449.  \} 
450. 
451. // It is now time to start up the app processes...
452. 
453. **if** (devicePolicy != **null**) \{ 
454.  devicePolicy.systemReady(); 
455.  \} 
456. 
457. **if** (notification != **null**) \{ 
458.  notification.systemReady(); 
459.  \} 
460. 
461. **if** (statusBar != **null**) \{ 
462.  statusBar.systemReady(); 
463.  \} 
464.  wm.systemReady(); 
465.  power.systemReady(); 
466. **try** \{ 
467.  pm.systemReady(); 
468.  \} **catch** (RemoteException e) \{ 
469.  \} 
470. 
471. // These are needed to propagate to the runnable below.
472. **final** StatusBarManagerService statusBarF = statusBar; 
473. **final** BatteryService batteryF = battery; 
474. **final** ConnectivityService connectivityF = connectivity; 
475. **final** DockObserver dockF = dock; 
476. **final** UsbService usbF = usb; 
477. **final** ThrottleService throttleF = throttle; 
478. **final** UiModeManagerService uiModeF = uiMode; 
479. **final** AppWidgetService appWidgetF = appWidget; 
480. **final** WallpaperManagerService wallpaperF = wallpaper; 
481. **final** InputMethodManagerService immF = imm; 
482. **final** RecognitionManagerService recognitionF = recognition; 
483. **final** LocationManagerService locationF = location; 
484. 
485. // We now tell the activity manager it is okay to run third party
486. // code. It will call back into us once it has gotten to the state
487. // where third party code can really run (but before it has actually
488. // started launching the initial applications), for us to complete our
489. // initialization.
490.  ((ActivityManagerService)ActivityManagerNative.getDefault()) 
491.  .systemReady(**new** Runnable() \{ 
492. **public****void** run() \{ 
493.  Slog.i(TAG, "Making services ready"); 
494. 
495. **if** (statusBarF != **null**) statusBarF.systemReady2(); 
496. **if** (batteryF != **null**) batteryF.systemReady(); 
497. **if** (connectivityF != **null**) connectivityF.systemReady(); 
498. **if** (dockF != **null**) dockF.systemReady(); 
499. **if** (usbF != **null**) usbF.systemReady(); 
500. **if** (uiModeF != **null**) uiModeF.systemReady(); 
501. **if** (recognitionF != **null**) recognitionF.systemReady(); 
502.  Watchdog.getInstance().start(); 
503. 
504. // It is now okay to let the various system services start their
505. // third party code...
506. 
507. **if** (appWidgetF != **null**) appWidgetF.systemReady(safeMode); 
508. **if** (wallpaperF != **null**) wallpaperF.systemReady(); 
509. **if** (immF != **null**) immF.systemReady(); 
510. **if** (locationF != **null**) locationF.systemReady(); 
511. **if** (throttleF != **null**) throttleF.systemReady(); 
512.  \} 
513.  \}); 
514. 
515. // For debug builds, log event loop stalls to dropbox for analysis.
516. **if** (StrictMode.conditionallyEnableDebugLogging()) \{ 
517.  Slog.i(TAG, "Enabled StrictMode for system server main thread."); 
518.  \} 
519. 
520.  Looper.loop(); 
521.  Slog.d(TAG, "System ServerThread is exiting!"); 
522.  \} 
523. \} 
524.

这个函数除了启动了很多系统服务，自己慢慢研究

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