Android 启动过程汇总

核心提示：important service. The source is in device/servers/app.media: start AudioFlinger, MediaPlayerService and CameraService. The source is in device/commands/mediase

important service. The source is in device/servers/app.

media: start AudioFlinger, MediaPlayerService and CameraService. The source is in device/commands/mediaserver.

bootsound: play the default boot sound /system/media/audio/ui/boot.mp3. The source is in device/commands/playmp3.

dbus: start dbus daemon, it’s only used by BlueZ. The source is in device/system/Bluetooth/dbus-daemon.

hcid: redirect hcid’s stdout and stderr to the Android logging system. The source is in device/system/bin/logwrapper. By default is disabled.

hfag: start Bluetooth handsfree audio gateway, it’s only used by BlueZ. The source is in device/system/Bluetooth/bluez-utils. By default is disabled.

hsag: start Bluetooth headset audio gateway, it’s only used by BlueZ. The source is in device/system/Bluetooth/bluez-utils. By default is disabled.

installd: start install package daemon. The source is in device/servers/installd.

flash_recovery: load /system/recovery.img. The source is in device/commands/recovery/mtdutils.

Zygote service does the following tasks step by step:

1. Create JAVA VM.

2. Register android native function for JAVA VM.

3. Call the main function in the JAVA class named com.android.internal.os.ZygoteInit whose source is device/java/android/com/android/internal/os/ZygoteInit.java.

a) Load ZygoteInit class

b) Register zygote socket

c) Load preload classes(the default file is device/java/android/preloaded-classes)

d) Load preload resources

e) Call Zygote::forkSystemServer (implemented in device/dalvik/vm/InternalNative.c) to fork a new process. In the new process, call the main function in the JAVA class named com.android.server.SystemServer, whose source is in device/java/services/com/android/server.

i. Load libandroid_servers.so

ii. Call JNI native init1 function implemented in