drivers/misc/tizen-inform-reboot.c

   1 /*
   2  * Tizen reboot parameter passing notifier
   3  *
   4  * Written by: Junghoon Kim <jhoon20.kim@samsung.com>
   5  *
   6  * Copyright (C) 2017 Samsung Electronics Co., Ltd.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/notifier.h>
  14 #include <linux/reboot.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/file.h>
  17 #include <linux/fcntl.h>
  18 #include <linux/uaccess.h>
  19
  20 static int inform_reboot_notifier(struct notifier_block *nb,
  21                                                 unsigned long val, void *buf)
  22 {
  23         char *cmd = buf;
  24         char *filename = CONFIG_TIZEN_INFORM_PATH;
  25         struct file *file;
  26         int fd;
  27         loff_t pos = 0;
  28         mm_segment_t old_fs = get_fs();
  29
  30         set_fs(KERNEL_DS);
  31
  32         fd = sys_open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0644);
  33         if (fd >= 0) {
  34                 file = fget(fd);
  35                 if (file) {
  36                         if (cmd) {
  37                                 if (!strncmp(cmd, "fota", 4))
  38                                         cmd = "upgr";
  39                                 else if (!strncmp(cmd, "recovery", 8))
  40                                         cmd = "rcvr";
  41                                 else
  42                                         cmd = "ndef";
  43                         } else
  44                                 cmd = "norm";
  45
  46                         vfs_write(file, cmd, strlen(cmd), &pos);
  47                         vfs_fsync(file, 0);
  48                         fput(file);
  49                 }
  50                 sys_close(fd);
  51                 /* to guarantee all file data and metadata sync */
  52                 emergency_sync();
  53         } else {
  54                 pr_err("Reboot parameter passing is failed.\n"
  55                                 "Inform file path should be described correctly in config.\n");
  56         }
  57
  58         set_fs(old_fs);
  59
  60         return NOTIFY_DONE;
  61 }
  62
  63 static struct notifier_block nb_inform_reboot_block = {
  64         .notifier_call = inform_reboot_notifier
  65 };
  66
  67 static int __init inform_reboot_init(void)
  68 {
  69         /* to support reboot parameter passing */
  70         register_reboot_notifier(&nb_inform_reboot_block);
  71         return 0;
  72 }
  73
  74 subsys_initcall(inform_reboot_init);