arch/common/boot/grub2/disk/fs_uuid.c

   1 /* fs_uuid.c - Access disks by their filesystem UUID.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2007,2008  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/disk.h>
  21 #include <grub/dl.h>
  22 #include <grub/kernel.h>
  23 #include <grub/misc.h>
  24 #include <grub/mm.h>
  25 #include <grub/types.h>
  26
  27 #include <grub/fs.h>
  28
  29 static grub_device_t
  30 search_fs_uuid (const char *key, unsigned long *count)
  31 {
  32   *count = 0;
  33   grub_device_t ret = NULL;
  34
  35   auto int iterate_device (const char *name);
  36   int iterate_device (const char *name)
  37     {
  38       grub_device_t dev;
  39
  40       dev = grub_device_open (name);
  41       if (dev)
  42         {
  43           grub_fs_t fs;
  44
  45           fs = grub_fs_probe (dev);
  46           if (fs && fs->uuid)
  47             {
  48               char *uuid;
  49
  50               (fs->uuid) (dev, &uuid);
  51               if (grub_errno == GRUB_ERR_NONE && uuid)
  52                 {
  53                   (*count)++;
  54
  55                   if (grub_strcmp (uuid, key) == 0)
  56                     {
  57                       ret = dev;
  58                       grub_free (uuid);
  59                       return 1;
  60                     }
  61                   grub_free (uuid);
  62                 }
  63             }
  64
  65           grub_device_close (dev);
  66         }
  67
  68       grub_errno = GRUB_ERR_NONE;
  69       return 0;
  70     }
  71
  72   grub_device_iterate (iterate_device);
  73
  74   return ret;
  75 }
  76
  77 static grub_err_t
  78 grub_fs_uuid_open (const char *name, grub_disk_t disk)
  79 {
  80   grub_device_t dev;
  81
  82   if (grub_strncmp (name, "UUID=", sizeof ("UUID=")-1))
  83     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a UUID virtual volume");
  84
  85   dev = search_fs_uuid (name + sizeof ("UUID=") - 1, &disk->id);
  86   if (! dev)
  87     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no matching UUID found");
  88
  89   disk->total_sectors = dev->disk->total_sectors;
  90   disk->has_partitions = 0;
  91   disk->partition = dev->disk->partition;
  92   disk->data = dev->disk;
  93
  94   return GRUB_ERR_NONE;
  95 }
  96
  97 static void
  98 grub_fs_uuid_close (grub_disk_t disk __attribute((unused)))
  99 {
 100 }
 101
 102 static grub_err_t
 103 grub_fs_uuid_read (grub_disk_t disk, grub_disk_addr_t sector,
 104                    grub_size_t size, char *buf)
 105 {
 106   grub_disk_t parent = disk->data;
 107   return parent->dev->read (parent, sector, size, buf);
 108 }
 109
 110 static grub_err_t
 111 grub_fs_uuid_write (grub_disk_t disk, grub_disk_addr_t sector,
 112                     grub_size_t size, const char *buf)
 113 {
 114   grub_disk_t parent = disk->data;
 115   return parent->dev->write (parent, sector, size, buf);
 116 }
 117
 118 static struct grub_disk_dev grub_fs_uuid_dev =
 119   {
 120     .name = "fs_uuid",
 121     .id = GRUB_DISK_DEVICE_UUID_ID,
 122     .open = grub_fs_uuid_open,
 123     .close = grub_fs_uuid_close,
 124     .read = grub_fs_uuid_read,
 125     .write = grub_fs_uuid_write,
 126     .next = 0
 127   };
 128
 129 GRUB_MOD_INIT(fs_uuid)
 130 {
 131   grub_disk_dev_register (&grub_fs_uuid_dev);
 132 }
 133
 134 GRUB_MOD_FINI(fs_uuid)
 135 {
 136   grub_disk_dev_unregister (&grub_fs_uuid_dev);
 137 }