恢复出厂设置 Factory Reset 调用过程

来源：互联网发布：mac 符号编辑：程序博客网时间：2024/05/01 21:57

过程分两大步

1. Main system 往/cache/recovery/command写命令wipe-data，重启手机
2. bootloader引导到recovery分区，执行wipe-data, 重启手机

1. Main system 往/cache/recovery/command写命令wipe-data，重启手机
packages/apps/Settings/src/com/android/settings/MasterClearConfirm.java
getActivity().sendBroadcast(new Intent("android.intent.action.MASTER_CLEAR"));

packages/apps/Settings/src/com/android/settings/MasterClear.java
frameworks/base/services/java/com/android/server/MasterClearReceiver.java
new Thread("Reboot")
RecoverySystem.rebootWipeUserData(context)

frameworks/base/core/java/android/os/RecoverySystem.java
bootCommand(context, "--wipe_data\n--locale=" + Locale.getDefault().toString());
bootCommand
   write command wipe-data to /cache/recovery/command
   pm.reboot("recovery");

frameworks/base/core/java/android/os/PowerManager.java
frameworks/base/services/java/com/android/server/power/PowerManagerService.java
frameworks/base/services/java/com/android/server/power/ShutdownThread.java
   PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
   pm.reboot("recovery");
      mService.reboot(false, reason, true)
         shutdownOrRebootInternal(false, confirm, reason, wait);
            ShutdownThread.shutdown(mContext, confirm); (shutdown)
            ShutdownThread.reboot(mContext, reason, confirm); (reboot)
              shutdownInner(context, confirm);
                 beginShutdownSequence(context)
                   setprop sys.shutdown.requested recovery
                   rebootOrShutdown(mReboot, mRebootReason);
                     PowerManagerService.lowLevelReboot(reason)
                        SystemProperties.set("sys.powerctl", "reboot," + reason); Thread.sleep(20000);

system/core/rootdir/init.rc
on property:sys.powerctl=*
    powerctl ${sys.powerctl}
        KEYWORD(powerctl,    COMMAND, 1, do_powerctl)   system/core/init/keywords.h
          do_powerctl()   system/core/init/builtins.c
              do_reboot(cmd, 0, reboot_target);   cmd = ANDROID_RB_RESTART2;   system/core/init/reboot.c
                __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,LINUX_REBOOT_CMD_RESTART2, arg);
                  __reboot bionic/libc/arch-arm/syscalls/__reboot.S

kernel/kernel/sys.c
SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,void __user *, arg)
   kernel_restart(char *cmd)
     machine_restart(char *cmd) kernel/arch/arm/kernel/process.c
        machine_shutdown()
        arm_pm_restart(reboot_mode,cmd)   kernel/arch/arm/kernel/process.c
         pm_power_off = msm_pm_power_off;
         arm_pm_restart = msm_pm_restart;              /kernel/arch/arm/mach-msm/restart_7k.c
             setup_mm_for_reboot   kernel/arch/unicore32/mm/mmu.c
             msm_proc_comm   /kernel/arch/arm/mach-msm/proc_msm.c

2. bootloader引导到recovery分区，执行wipe-data, 重启手机
bootable/recovery/etc/init.rc
service recovery /sbin/recovery

bootable/recovery/recovery.c
读取/cache/recovery/command,判定哪种命令，如果是wipe-data,
erase_volume("/data");
erase_volume("/cache");
reboot();
check master reset log: /cache/recovery/log

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