Android9：Car AutoMotive系统（Carservice 服务）开机流程

目的：学习并记录Android原生Car 系统。
启动流程：
（1）SystemServer.java 启动CarServiceHelperService服务
frameworks/base/services/java/com/android/server/SystemServer.java

private static final String CAR_SERVICE_HELPER_SERVICE_CLASS =
            "com.android.internal.car.CarServiceHelperService";
            
 public static void main(String[] args) {
        new SystemServer().run();
    }

private void run() {
 startOtherServices();
}

private void startOtherServices() {
 if(mPackageManager.hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) {
     traceBeginAndSlog("StartCarServiceHelperService");
     mSystemServiceManager.startService(CAR_SERVICE_HELPER_SERVICE_CLASS);
     traceEnd();
    }
}
    

（2）CarServiceHelperService.java ，绑定carservice服务 /frameworks/opt/car/services/src/com/android/internal/car/CarServiceHelperService.java

private final ServiceConnection mCarServiceConnection = new ServiceConnection() {

        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            Slog.i(TAG, "**CarService connected**");
            mCarService = iBinder;
            // Cannot depend on ICar which is defined in CarService, so handle binder call directly
            // instead.
            // void setCarServiceHelper(in IBinder helper)
            Parcel data = Parcel.obtain();
            data.writeInterfaceToken(CAR_SERVICE_INTERFACE);
            data.writeStrongBinder(mHelper.asBinder());
            try {
                mCarService.transact(IBinder.FIRST_CALL_TRANSACTION, // setCarServiceHelper
                        data, null, Binder.FLAG_ONEWAY);
            } catch (RemoteException e) {
                Slog.w(TAG, "RemoteException from car service", e);
                handleCarServiceCrash();
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {
            handleCarServiceCrash();
        }
    };
    
@Override
    public void onStart() {
        Intent intent = new Intent();
        //packages/services/Car/service/src/com/android/car/CarService.java
        //包名为com.android.car
        intent.setPackage("com.android.car");
        intent.setAction(CAR_SERVICE_INTERFACE);
        Slog.wtf(TAG, "liliadd:will start car service");
        if (!getContext().bindServiceAsUser(intent, mCarServiceConnection, Context.BIND_AUTO_CREATE,
                UserHandle.SYSTEM)) {
            Slog.wtf(TAG, "cannot start car service");
        }
        System.loadLibrary("car-framework-service-jni");
    }

(3)CarService.java ，创建ICarImpl实例，并调用init方法。
packages/services/Car/service/src/com/android/car/CarService.java

@Override
    public void onCreate() {
    mICarImpl = new ICarImpl(this,
                mVehicle,
                SystemInterface.Builder.defaultSystemInterface(this).build(),
                mCanBusErrorNotifier,
                mVehicleInterfaceName);
        mICarImpl.init();
    }

（4）ICarImpl.java 构造函数中启动服务。并对服务初始化
/packages/services/Car/service/src/com/android/car/ICarImpl.java

@MainThread
    void init() {
        traceBegin("VehicleHal.init");
        mHal.init();
        traceEnd();
        traceBegin("CarService.initAllServices");
        for (CarServiceBase service : mAllServices) {
            service.init();
        }
        traceEnd();
    }

调用对应服务得init方法。

注意：
1、CarService本质上是一个特殊的APP，它编译后生成CarService.apk；在真机上，它是在/system/priv-app/CarService/CarService.apk这里。
2、packages/services/Car/car_product/build/car.mk里面决定了是否编译相关apk。

参考文档：
https://blog.csdn.net/qilu0882/article/details/84990164
整理Android9 Car AutoMotive得启动流程。

本文地址：https://blog.csdn.net/zhuowalun8427/article/details/107190026