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         loff_t pos = 0;
  27         mm_segment_t old_fs = get_fs();
  28
  29         set_fs(KERNEL_DS);
  30
  31         file = filp_open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0644);
  32         if (!IS_ERR(file)) {
  33                 struct super_block *sb = file->f_path.dentry->d_sb;
  34
  35                 if (cmd) {
  36                         if (!strncmp(cmd, "fota", 4))
  37                                 cmd = "upgr";
  38                         else if (!strncmp(cmd, "recovery", 8))
  39                                 cmd = "rcvr";
  40                         else if (!strncmp(cmd, "download", 8))
  41                                 cmd = "dwnl";
  42                         else
  43                                 cmd = "ndef";
  44                 } else
  45                         cmd = "norm";
  46
  47                 vfs_write(file, cmd, strlen(cmd), &pos);
  48
  49                 down_read(&sb->s_umount);
  50                 sync_filesystem(sb);
  51                 up_read(&sb->s_umount);
  52
  53                 fput(file);
  54         } else {
  55                 pr_err("Reboot parameter passing is failed.\n"
  56                                 "Inform file path should be described correctly in config.\n");
  57         }
  58
  59         set_fs(old_fs);
  60
  61         return NOTIFY_DONE;
  62 }
  63
  64 static struct notifier_block nb_inform_reboot_block = {
  65         .notifier_call = inform_reboot_notifier,
  66         .priority = 256,
  67 };
  68
  69 static int __init inform_reboot_init(void)
  70 {
  71         /* to support reboot parameter passing */
  72         register_reboot_notifier(&nb_inform_reboot_block);
  73         return 0;
  74 }
  75
  76 subsys_initcall(inform_reboot_init);