android reboot

參考:

http://blog.csdn.net/airk000/article/details/9177077

http://blog.csdn.net/zhenwenxian/article/details/6766803

http://www.tuicool.com/articles/jYFZFf

http://blog.csdn.net/zzobin/article/details/7195060

http://blog.csdn.net/androiddeveloper_lee/article/details/9086447

framework 
./base/core/java/com/android/internal/app/ShutdownThread.java
/**
     * Do not call this directly. Use {@link #reboot(Context, String, boolean)}
     * or {@link #shutdown(Context, boolean)} instead.
     *
     * @param reboot true to reboot or false to shutdown
     * @param reason reason for reboot
     */
    public static void rebootOrShutdown(boolean reboot, String reason) {
        if (reboot) {
            Log.i(TAG, "Rebooting, reason: " + reason);
            try {
                Power.reboot(reason);
            } catch (Exception e) {
                Log.e(TAG, "Reboot failed, will attempt shutdown instead", e);
            }
        } else if (SHUTDOWN_VIBRATE_MS > 0) {
            // vibrate before shutting down
            Vibrator vibrator = new Vibrator();
            try {
                vibrator.vibrate(SHUTDOWN_VIBRATE_MS);
            } catch (Exception e) {
                // Failure to vibrate shouldn't interrupt shutdown.  Just log it.
                Log.w(TAG, "Failed to vibrate during shutdown.", e);
            }

            // vibrator is asynchronous so we need to wait to avoid shutting down too soon.
            try {
                Thread.sleep(SHUTDOWN_VIBRATE_MS);
            } catch (InterruptedException unused) {
            }
        }

        // Shutdown power
        Log.i(TAG, "Performing low-level shutdown...");
        Power.shutdown();
    }




./base/core/jni/android_os_Power.cpp  不一樣
static void android_os_Power_shutdown(JNIEnv *env, jobject clazz)
{
    android_reboot(ANDROID_RB_POWEROFF, 0, 0);
}

extern int go_recovery(void);

static void android_os_Power_reboot(JNIEnv *env, jobject clazz, jstring reason)
{
    if (reason == NULL) {
        android_reboot(ANDROID_RB_RESTART, 0, 0);
    } else {
        const char *chars = env->GetStringUTFChars(reason, NULL);
        //android_reboot(ANDROID_RB_RESTART2, 0, (char *) chars);
        go_recovery();
        android_reboot(ANDROID_RB_RESTART, 0, 0);
        env->ReleaseStringUTFChars(reason, chars);  // In case it fails.
    }
    jniThrowIOException(env, errno);
}

ANDOID_ROOT\system\core\libcutils\android_reboot.c
int android_reboot(int cmd, int flags, char *arg)
{
    int ret;

    if (!(flags & ANDROID_RB_FLAG_NO_SYNC))
        sync();

    if (!(flags & ANDROID_RB_FLAG_NO_REMOUNT_RO))
        remount_ro();

    switch (cmd) {
        case ANDROID_RB_RESTART:
            ret = reboot(RB_AUTOBOOT);
            break;

        case ANDROID_RB_POWEROFF:
            ret = reboot(RB_POWER_OFF);
            break;

        case ANDROID_RB_RESTART2:
            ret = __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
                           LINUX_REBOOT_CMD_RESTART2, arg);
            break;

        default:
            ret = -1;
    }

    return ret;
}

android4.0/frameworks/base/core/jni/misc_rw.cpp
/* force the next boot to recovery */
int go_recovery(void){
	
	LOGE("go_recovery  =================\n");
	struct bootloader_message boot, temp;

	memset(&boot, 0, sizeof(boot));
	strcpy(boot.command, "boot-recovery");
	if (set_bootloader_message_block(&boot, MISC_DEVICE) )
		return -1;

	//read for compare
	memset(&temp, 0, sizeof(temp));
	if (get_bootloader_message_block(&temp, MISC_DEVICE))
		return -1;

	if( memcmp(&boot, &temp, sizeof(boot)) )
		return -1;
	LOGE("go_recovery  ++++++++++++++++++++++\n");
	return 0;

}