android service 启动源码流程分析

android sevice 启动时序图

android service 启动流程分析.png
   @Override
    public ComponentName startService(Intent service) {
        warnIfCallingFromSystemProcess();
        return startServiceCommon(service, false, mUser);
    }
    
     private ComponentName startServiceCommon(Intent service, boolean requireForeground,
            UserHandle user) {
        try {
            validateServiceIntent(service);
            service.prepareToLeaveProcess(this);
            ComponentName cn = ActivityManager.getService().startService(
                mMainThread.getApplicationThread(), service, service.resolveTypeIfNeeded(
                            getContentResolver()), requireForeground,
                            getOpPackageName(), user.getIdentifier());
            if (cn != null) {
                if (cn.getPackageName().equals("!")) {
                    throw new SecurityException(
                            "Not allowed to start service " + service
                            + " without permission " + cn.getClassName());
                } else if (cn.getPackageName().equals("!!")) {
                    throw new SecurityException(
                            "Unable to start service " + service
                            + ": " + cn.getClassName());
                } else if (cn.getPackageName().equals("?")) {
                    throw new IllegalStateException(
                            "Not allowed to start service " + service + ": " + cn.getClassName());
                }
            }
            return cn;
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

  • 跨进程调用ActivityManagerService中的startService

    @Override
    public ComponentName startService(IApplicationThread caller, Intent service,
            String resolvedType, boolean requireForeground, String callingPackage, int userId)
            throws TransactionTooLargeException {
        enforceNotIsolatedCaller("startService");
        // Refuse possible leaked file descriptors
        if (service != null && service.hasFileDescriptors() == true) {
            throw new IllegalArgumentException("File descriptors passed in Intent");
        }

        if (callingPackage == null) {
            throw new IllegalArgumentException("callingPackage cannot be null");
        }

        if (DEBUG_SERVICE) Slog.v(TAG_SERVICE,
                "*** startService: " + service + " type=" + resolvedType + " fg=" + requireForeground);
        synchronized(this) {
            final int callingPid = Binder.getCallingPid();
            final int callingUid = Binder.getCallingUid();
            final long origId = Binder.clearCallingIdentity();
            ComponentName res;
            try {
                res = mServices.startServiceLocked(caller, service,
                        resolvedType, callingPid, callingUid,
                        requireForeground, callingPackage, userId);
            } finally {
                Binder.restoreCallingIdentity(origId);
            }
            return res;
        }
    }

  • ActiveServices 一系列调用,最终到达ActivityThread快乐的彼岸
 ComponentName startServiceLocked(IApplicationThread caller, Intent service, String resolvedType,
            int callingPid, int callingUid, boolean fgRequired, String callingPackage, final int userId)
            throws TransactionTooLargeException {
                                ....
            ComponentName cmp = startServiceInnerLocked(smap, service, r, callerFg, addToStarting);
            }
            
    ComponentName startServiceInnerLocked(ServiceMap smap, Intent service, ServiceRecord r,
            boolean callerFg, boolean addToStarting) throws TransactionTooLargeException {
        ServiceState stracker = r.getTracker();
        if (stracker != null) {
            stracker.setStarted(true, mAm.mProcessStats.getMemFactorLocked(), r.lastActivity);
        }
        r.callStart = false;
        synchronized (r.stats.getBatteryStats()) {
            r.stats.startRunningLocked();
        }
        String error = bringUpServiceLocked(r, service.getFlags(), callerFg, false, false);
        if (error != null) {
            return new ComponentName("!!", error);
        }

        if (r.startRequested && addToStarting) {
            boolean first = smap.mStartingBackground.size() == 0;
            smap.mStartingBackground.add(r);
            r.startingBgTimeout = SystemClock.uptimeMillis() + mAm.mConstants.BG_START_TIMEOUT;
            if (DEBUG_DELAYED_SERVICE) {
                RuntimeException here = new RuntimeException("here");
                here.fillInStackTrace();
                Slog.v(TAG_SERVICE, "Starting background (first=" + first + "): " + r, here);
            } else if (DEBUG_DELAYED_STARTS) {
                Slog.v(TAG_SERVICE, "Starting background (first=" + first + "): " + r);
            }
            if (first) {
                smap.rescheduleDelayedStartsLocked();
            }
        } else if (callerFg || r.fgRequired) {
            smap.ensureNotStartingBackgroundLocked(r);
        }

        return r.name;
    }
    
     private String bringUpServiceLocked(ServiceRecord r, int intentFlags, boolean execInFg,
            boolean whileRestarting, boolean permissionsReviewRequired){
            // 此处省略若干行
            if (!isolated) {
            app = mAm.getProcessRecordLocked(procName, r.appInfo.uid, false);
            if (DEBUG_MU) Slog.v(TAG_MU, "bringUpServiceLocked: appInfo.uid=" + r.appInfo.uid
                        + " app=" + app);
            if (app != null && app.thread != null) {
                try {
                    app.addPackage(r.appInfo.packageName, r.appInfo.versionCode, mAm.mProcessStats);
                    realStartServiceLocked(r, app, execInFg);
                    return null;
                } catch (TransactionTooLargeException e) {
                    throw e;
                } catch (RemoteException e) {
                    Slog.w(TAG, "Exception when starting service " + r.shortName, e);
                }

                // If a dead object exception was thrown -- fall through to
                // restart the application.
            }
        } 
            // 此处省略若干行
            
     }

  • 跨进程调用ActivityThread
  1. 通过aidl的调用调用scheduleCreateService创建service
  2. r.postNotification(); 如果设置更新通知栏,进行通知栏的更新,setServiceForeground
    private final void realStartServiceLocked(ServiceRecord r,
            ProcessRecord app, boolean execInFg) throws RemoteException {
             // 此处省略若干行
             app.forceProcessStateUpTo(ActivityManager.PROCESS_STATE_SERVICE);
            app.thread.scheduleCreateService(r, r.serviceInfo,
                    mAm.compatibilityInfoForPackageLocked(r.serviceInfo.applicationInfo),
                    app.repProcState);
            r.postNotification();
             // 此处省略若干行
   }
   
   // serviceRecord  内部方法
    public void postNotification() {
        final int appUid = this.appInfo.uid;
        final int appPid = this.app.pid;
        if (this.foregroundId != 0 && this.foregroundNoti != null) {
            final String localPackageName = this.packageName;
            final int localForegroundId = this.foregroundId;
            final Notification localForegroundNoti = this.foregroundNoti;
            this.ams.mHandler.post(new Runnable() {
                public void run() {
                    NotificationManagerInternal nm = (NotificationManagerInternal)LocalServices.getService(NotificationManagerInternal.class);
                    if (nm != null) {
                        try {
                            if (localForegroundNoti.icon == 0) {
                                localForegroundNoti.icon = ServiceRecord.this.appInfo.icon;
                                localForegroundNoti.contentView = null;
                                localForegroundNoti.bigContentView = null;
                                CharSequence appName = ServiceRecord.this.appInfo.loadLabel(ServiceRecord.this.ams.mContext.getPackageManager());
                                if (appName == null) {
                                    appName = ServiceRecord.this.appInfo.packageName;
                                }

                                Context ctx = null;

                                try {
                                    ctx = ServiceRecord.this.ams.mContext.createPackageContext(ServiceRecord.this.appInfo.packageName, 0);
                                    Intent runningIntent = new Intent("android.settings.APPLICATION_DETAILS_SETTINGS");
                                    runningIntent.setData(Uri.fromParts("package", ServiceRecord.this.appInfo.packageName, (String)null));
                                    PendingIntent pi = PendingIntent.getActivity(ServiceRecord.this.ams.mContext, 0, runningIntent, 134217728);
                                    localForegroundNoti.color = ServiceRecord.this.ams.mContext.getResources().getColor(17170521);
                                    localForegroundNoti.setLatestEventInfo(ctx, ServiceRecord.this.ams.mContext.getString(17040496, new Object[]{appName}), ServiceRecord.this.ams.mContext.getString(17040497, new Object[]{appName}), pi);
                                } catch (NameNotFoundException var6) {
                                    localForegroundNoti.icon = 0;
                                }
                            }

                            if (localForegroundNoti.icon == 0) {
                                throw new RuntimeException("icon must be non-zero");
                            }

                            int[] outId = new int[1];
                            nm.enqueueNotification(localPackageName, localPackageName, appUid, appPid, (String)null, localForegroundId, localForegroundNoti, outId, ServiceRecord.this.userId);
                        } catch (RuntimeException var7) {
                            Slog.w("ActivityManager", "Error showing notification for service", var7);
                            ServiceRecord.this.ams.setServiceForeground(ServiceRecord.this.name, ServiceRecord.this, 0, (Notification)null, true);
                            ServiceRecord.this.ams.crashApplication(appUid, appPid, localPackageName, "Bad notification for startForeground: " + var7);
                        }

                    }
                }
            });
        }

    }

  • 核心ActivityThread 流程
    1.handleCreateService 中进行attach 和service的生命周期
        public final void scheduleCreateService(IBinder token,
                ServiceInfo info, CompatibilityInfo compatInfo, int processState) {
            updateProcessState(processState, false);
            CreateServiceData s = new CreateServiceData();
            s.token = token;
            s.info = info;
            s.compatInfo = compatInfo;

            sendMessage(H.CREATE_SERVICE, s);
        }
        
     private void handleCreateService(CreateServiceData data) {
        // If we are getting ready to gc after going to the background, well
        // we are back active so skip it.
        unscheduleGcIdler();

        LoadedApk packageInfo = getPackageInfoNoCheck(
                data.info.applicationInfo, data.compatInfo);
        Service service = null;
        try {
            java.lang.ClassLoader cl = packageInfo.getClassLoader();
            service = (Service) cl.loadClass(data.info.name).newInstance();
        } catch (Exception e) {
            if (!mInstrumentation.onException(service, e)) {
                throw new RuntimeException(
                    "Unable to instantiate service " + data.info.name
                    + ": " + e.toString(), e);
            }
        }

        try {
            if (localLOGV) Slog.v(TAG, "Creating service " + data.info.name);

            ContextImpl context = ContextImpl.createAppContext(this, packageInfo);
            context.setOuterContext(service);

            Application app = packageInfo.makeApplication(false, mInstrumentation);
            service.attach(context, this, data.info.name, data.token, app,
                    ActivityManager.getService());
            service.onCreate();
            mServices.put(data.token, service);
            try {
                ActivityManager.getService().serviceDoneExecuting(
                        data.token, SERVICE_DONE_EXECUTING_ANON, 0, 0);
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
        } catch (Exception e) {
            if (!mInstrumentation.onException(service, e)) {
                throw new RuntimeException(
                    "Unable to create service " + data.info.name
                    + ": " + e.toString(), e);
            }
        }
    }

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