IPCThreadState
BpInterface
/dev/binder
BpBinder
+transact()
IServiceManager
+ gDefaultServiceManager
+ asInterface() //return BpServiceManager+ getService();+ addService();+ listServices();
IInterface
IBinder
talkwithDriver()
RefBase
封装了一个APIdefaultServiceManager() == BpServiceManager （BpBinder(0)）
LibBinder.so
binder_loop
BBinder
+OnTransact()
BnInterface
BpRefBase
BpServiceManager (没人用？)
+ getService()+ addService()+ listServices()
svcmgr_handler
transact()
