指纹模块流程分析(二)之Fingerprint framework初始化流程
二、Fingerprint framework初始化流程
在系统开机的时候，会启动各种Service，包括FingerprintService。从下图的开机log（sys_log.boot）中可以看出：
05-29 10:37:57.870869 1127 1127 I SystemServiceManager: Starting com.android.server.dreams.DreamManagerService
05-29 10:37:57.874643 1127 1127 I SystemServer: StartAssetAtlasService
05-29 10:37:57.883240 1127 1127 I SystemServiceManager: Starting com.android.server.print.PrintManagerService
05-29 10:37:57.910104 1127 1127 I SystemServiceManager: Starting com.android.server.restrictions.RestrictionsManagerService
05-29 10:37:57.913926 1127 1127 I SystemServiceManager: Starting com.android.server.media.MediaSessionService
05-29 10:37:57.926584 1127 1127 I SystemServer: StartMediaRouterService
05-29 10:37:57.939619 1127 1127 I SystemServiceManager: Starting com.android.server.trust.TrustManagerService
05-29 10:37:57.952689 1127 1127 I SystemServiceManager: Starting com.android.server.fingerprint.FingerprintService
05-29 10:37:58.866228 1127 1127 V FingerprintService: Fingerprint HAL id: 488345235968
05-29 10:37:58.867305 1127 1127 I SystemServer: StartBackgroundDexOptService
FingerprintService的启动在SystemServer.Java的startOtherService方法中
/**
* Starts a miscellaneous grab bag of stuff that has yet to be refactored
* and organized.
*/
private void startOtherServices() {
final Context context = mSystemContext;
VibratorService vibrator = null;
IMountService mountService = null;
.......
//启动FingerprintService
if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_FINGERPRINT)) {
mSystemServiceManager.startService(FingerprintService.class);
}
......
这里启动的时候，会将FingerprintService添加到ServiceManager中去，如下图：
将FingerprintService添加到ServiceManager中后，在SystemServiceRegistry.java中静态代码块中注册服务的时候，可以从ServiceManager中获取FingerprintService的Binder对象，从而可以构造出FingerprintManager对象，这样app端就可以通过Context来获取FingerprintManager对象。另外FingerprintService的onStart()方法中还会调用getFingerprintDaemon()来完成以下步骤：
//①获取fingerprintd
//②向fingerprintd注册回调函数mDaemonCallback
//③调用获取fingerprintd的openhal函数
public IFingerprintDaemon getFingerprintDaemon() {
//①获取fingerprintd
mDaemon = IFingerprintDaemon.Stub.asInterface(ServiceManager.getService(
FINGERPRINTD));
mDaemon.asBinder().linkToDeath(this, 0);
//②向fingerprintd注册回调函数mDaemonCallback
mDaemon.init(mDaemonCallback);
//③调用获取fingerprintd的openhal函数
mHalDeviceId = mDaemon.openHal();
......
}
app端通过Context获取FingerprintManager，通过调用FingerprintManager的接口来实现相应的功能，FingerprintManager转调FingerprintService中方法，FingerprintService负责管理整个注册，识别、删除指纹、检查权限等流程的逻辑，FingerprintService调用fingerprintd的接口，通过fingerprintd和FingerprintHal层进行通信。