（N）Telephony分析（三）之PhoneApp启动
此前，分析过，SystemServer的启动，那么接着上篇，继续分析PhoneApp的启动
首先，SystemServer启动时，进入其的main函数
SystemServer.java文件
public static void main(String[] args) {
new SystemServer().run();
}private void run() {
......
// Start services.
try {
Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartServices");
startBootstrapServices();
startCoreServices();
startOtherServices();
} catch (Throwable ex) {
......
}
......
}private void startBootstrapServices() {
......
// Activity manager runs the show.
mActivityManagerService = mSystemServiceManager.startService(
ActivityManagerService.Lifecycle.class).getService();
mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
mActivityManagerService.setInstaller(installer);
......
// Set up the Application instance for the system process and get started.
// Leo,调用ActivityManagerService对象爱那个的setSystemProcess方法
mActivityManagerService.setSystemProcess(); ......
}public T startService(Class serviceClass) {
try {
final String name = serviceClass.getName();
Slog.i(TAG, "Starting " + name);
Trace.traceBegin(Trace.TRACE_TAG_SYSTEM_SERVER, "StartService " + name);
// Create the service.
if (!SystemService.class.isAssignableFrom(serviceClass)) {
throw new RuntimeException("Failed to create " + name
+ ": service must extend " + SystemService.class.getName());
}
final T service;
try { // Leo, 原来是之调用了serviceClass的构造函数
Constructor constructor = serviceClass.getConstructor(Context.class); // Leo，得到serviceClass的对象
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);
}
// Register it.
mServices.add(service);
// Start it.
try { // Leo, 调用其onStart方法
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);
}
}public static final class Lifecycle extends SystemService {
private final ActivityManagerService mService;
// Leo, 构造函数中，新建了一个ActivityManagerService的对象
public Lifecycle(Context context) {
super(context);
mService = new ActivityManagerService(context);
}
@Override
// Leo，onStart方法中，其实就是调用了ActivityManagerService对象的start方法
public void onStart() {
mService.start();
}
// Leo，返回ActivityManagerService对象
public ActivityManagerService getService() {
return mService;
}
}接下来调用了ActivityManagerService对象的setSystemProcess方法
public void setSystemProcess() {
try {
// Leo, 将Service加入到ServiceManager中进行管理
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);
}
updateLruProcessLocked(app, false, null);
updateOomAdjLocked();
}
} catch (PackageManager.NameNotFoundException e) {
throw new RuntimeException(
"Unable to find android system package", e);
}
}接下来，查看ServiceServer的run方法中的其他方法，startOtherService
private void startOtherServices() {
......
// Leo, 调用ActivityManagerService的systemReady方法
mActivityManagerService.systemReady(......);
}public void systemReady(final Runnable goingCallback) {
......
startPersistentApps(PackageManager.MATCH_DIRECT_BOOT_AWARE);
.....
}private void startPersistentApps(int matchFlags) {
if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL) return;
synchronized (this) {
try {
final List apps = AppGlobals.getPackageManager()
.getPersistentApplications(STOCK_PM_FLAGS | matchFlags).getList();
for (ApplicationInfo app : apps) {
if (!"android".equals(app.packageName)) {
addAppLocked(app, false, null /* ABI override */);
}
}
} catch (RemoteException ex) {
}
}
}
......
......
// Leo, info is app, isolated is false, abiOverride is null
final ProcessRecord addAppLocked(ApplicationInfo info, boolean isolated,
String abiOverride) {
ProcessRecord app;
if (!isolated) {
app = getProcessRecordLocked(info.processName, info.uid, true);
} else {
app = null;
}
if (app == null) {
// Leo， 通过ApplicationInfo获取ProcessRecord
app = newProcessRecordLocked(info, null, isolated, 0);
updateLruProcessLocked(app, false, null);
updateOomAdjLocked();
}
// This package really, really can not be stopped.
try {
AppGlobals.getPackageManager().setPackageStoppedState(
info.packageName, false, UserHandle.getUserId(app.uid));
} catch (RemoteException e) {
} catch (IllegalArgumentException e) {
Slog.w(TAG, "Failed trying to unstop package "
+ info.packageName + ": " + e);
}
if ((info.flags & PERSISTENT_MASK) == PERSISTENT_MASK) {
app.persistent = true;
app.maxAdj = ProcessList.PERSISTENT_PROC_ADJ;
}
if (app.thread == null && mPersistentStartingProcesses.indexOf(app) < 0) {
mPersistentStartingProcesses.add(app);
// Leo，调用startProcessLocked，看这个方法的名称，应该是启动该应用
startProcessLocked(app, "added application", app.processName, abiOverride,
null /* entryPoint */, null /* entryPointArgs */);
}
return app;
}// Leo, hosting Type is "added application", addAppLocked is null, entryPoint is null, entryPointArgs is null
private final void startProcessLocked(ProcessRecord app, String hostingType,
String hostingNameStr, String abiOverride, String entryPoint, String[] entryPointArgs) {
// Leo, 配置启动进程的一些必要参数
...... if (entryPoint == null) entryPoint = "android.app.ActivityThread"; // Leo, 调用Process的start方法，看样子，是在这边启动进程，注意这边的entryPoint参数是"android.app.ActivityThread"
Process.ProcessStartResult startResult = Process.start(entryPoint,
app.processName, uid, uid, gids, debugFlags, mountExternal,
app.info.targetSdkVersion, app.info.seinfo, requiredAbi, instructionSet,
app.info.dataDir, entryPointArgs);
......
}public static final ProcessStartResult start(final String processClass,
final String niceName,
int uid, int gid, int[] gids,
int debugFlags, int mountExternal,
int targetSdkVersion,
String seInfo,
String abi,
String instructionSet,
String appDataDir,
String[] zygoteArgs) {
...... // Leo, 注意，此处的processClass为"android.app.ActivityThread"
return startViaZygote(processClass, niceName, uid, gid, gids,
debugFlags, mountExternal, targetSdkVersion, seInfo,
abi, instructionSet, appDataDir, zygoteArgs);
......
}public static void main(String[] args) {
......
ActivityThread thread = new ActivityThread();
thread.attach(false);
......
}private void attach(boolean system) {
// Leo, 调用IActivityManager的attachApplication
final IActivityManager mgr = ActivityManagerNative.getDefault();
try {
mgr.attachApplication(mAppThread);
} catch (RemoteException ex) {
throw ex.rethrowFromSystemServer();
}
}static public IActivityManager getDefault() {
return gDefault.get();
}private static final Singleton gDefault = new Singleton() {
protected IActivityManager create() {
IBinder b = ServiceManager.getService("activity");
if (false) {
Log.v("ActivityManager", "default service binder = " + b);
}
IActivityManager am = asInterface(b);
if (false) {
Log.v("ActivityManager", "default service = " + am);
}
return am;
}
}; 我们继续查看ActivityManagerProxy的attachApplication，此后通过一系列的Binder通信，调用的是ActivityManagerService的attachApplication方法，因此
public final void attachApplication(IApplicationThread thread) {
synchronized (this) {
int callingPid = Binder.getCallingPid();
final long origId = Binder.clearCallingIdentity();
// Leo，调用attachApplicationLocked方法
attachApplicationLocked(thread, callingPid);
Binder.restoreCallingIdentity(origId);
}
}private final boolean attachApplicationLocked(IApplicationThread thread,
int pid) {
......
thread.bindApplication(processName, appInfo, providers, app.instrumentationClass,
profilerInfo, app.instrumentationArguments, app.instrumentationWatcher,
app.instrumentationUiAutomationConnection, testMode,
mBinderTransactionTrackingEnabled, enableTrackAllocation,
isRestrictedBackupMode || !normalMode, app.persistent,
new Configuration(mConfiguration), app.compat,
getCommonServicesLocked(app.isolated),
mCoreSettingsObserver.getCoreSettingsLocked());
......
}
而IApplicationThread是什么呢？此地就不多说了，依旧是通过Binder通信来连接的IBinder，一个为ApplicationThreadProxy，另一个是ApplicationThread
因此最终调用的是ApplicationThread的bindApplication方法
ActivityThread.java
public final void bindApplication(String processName, ApplicationInfo appInfo,
List providers, ComponentName instrumentationName,
ProfilerInfo profilerInfo, Bundle instrumentationArgs,
IInstrumentationWatcher instrumentationWatcher,
IUiAutomationConnection instrumentationUiConnection, int debugMode,
boolean enableBinderTracking, boolean trackAllocation,
boolean isRestrictedBackupMode, boolean persistent, Configuration config,
CompatibilityInfo compatInfo, Map services, Bundle coreSettings) {
if (services != null) {
// Setup the service cache in the ServiceManager
ServiceManager.initServiceCache(services);
}
setCoreSettings(coreSettings);
AppBindData data = new AppBindData();
data.processName = processName;
data.appInfo = appInfo;
data.providers = providers;
data.instrumentationName = instrumentationName;
data.instrumentationArgs = instrumentationArgs;
data.instrumentationWatcher = instrumentationWatcher;
data.instrumentationUiAutomationConnection = instrumentationUiConnection;
data.debugMode = debugMode;
data.enableBinderTracking = enableBinderTracking;
data.trackAllocation = trackAllocation;
data.restrictedBackupMode = isRestrictedBackupMode;
data.persistent = persistent;
data.config = config;
data.compatInfo = compatInfo;
data.initProfilerInfo = profilerInfo;
sendMessage(H.BIND_APPLICATION, data);
} public void handleMessage(Message msg) {
if (DEBUG_MESSAGES) Slog.v(TAG, ">>> handling: " + codeToString(msg.what));
switch (msg.what) {
......
case BIND_APPLICATION:
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "bindApplication");
AppBindData data = (AppBindData)msg.obj;
// Leo, 调用handleBindApplication方法
handleBindApplication(data);
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
break;
......
}
}private void handleBindApplication(AppBindData data) {
......
// Continue loading instrumentation.
if (ii != null) {
final ApplicationInfo instrApp = new ApplicationInfo();
ii.copyTo(instrApp);
instrApp.initForUser(UserHandle.myUserId());
final LoadedApk pi = getPackageInfo(instrApp, data.compatInfo,
appContext.getClassLoader(), false, true, false);
final ContextImpl instrContext = ContextImpl.createAppContext(this, pi);
try {
final ClassLoader cl = instrContext.getClassLoader();
mInstrumentation = (Instrumentation)
cl.loadClass(data.instrumentationName.getClassName()).newInstance();
} catch (Exception e) {
throw new RuntimeException(
"Unable to instantiate instrumentation "
+ data.instrumentationName + ": " + e.toString(), e);
}
final ComponentName component = new ComponentName(ii.packageName, ii.name);
mInstrumentation.init(this, instrContext, appContext, component,
data.instrumentationWatcher, data.instrumentationUiAutomationConnection);
if (mProfiler.profileFile != null && !ii.handleProfiling
&& mProfiler.profileFd == null) {
mProfiler.handlingProfiling = true;
final File file = new File(mProfiler.profileFile);
file.getParentFile().mkdirs();
Debug.startMethodTracing(file.toString(), 8 * 1024 * 1024);
}
} else {
mInstrumentation = new Instrumentation();
}
......
try {
mInstrumentation.callApplicationOnCreate(app);
} catch (Exception e) {
if (!mInstrumentation.onException(app, e)) {
throw new RuntimeException(
"Unable to create application " + app.getClass().getName()
+ ": " + e.toString(), e);
}
}
......
}public void callApplicationOnCreate(Application app) {
app.onCreate();
}