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 #include <grub/partition.h>
  29
  30 static grub_device_t
  31 search_fs_uuid (const char *key, unsigned long *count)
  32 {
  33   *count = 0;
  34   grub_device_t ret = NULL;
  35
  36   auto int iterate_device (const char *name);
  37   int iterate_device (const char *name)
  38     {
  39       grub_device_t dev;
  40
  41       dev = grub_device_open (name);
  42       if (dev)
  43         {
  44           grub_fs_t fs;
  45
  46           fs = grub_fs_probe (dev);
  47           if (fs && fs->uuid)
  48             {
  49               char *uuid;
  50
  51               (fs->uuid) (dev, &uuid);
  52               if (grub_errno == GRUB_ERR_NONE && uuid)
  53                 {
  54                   (*count)++;
  55
  56                   if (grub_strcasecmp (uuid, key) == 0)
  57                     {
  58                       ret = dev;
  59                       grub_free (uuid);
  60                       return 1;
  61                     }
  62                   grub_free (uuid);
  63                 }
  64             }
  65
  66           grub_device_close (dev);
  67         }
  68
  69       grub_errno = GRUB_ERR_NONE;
  70       return 0;
  71     }
  72
  73   grub_device_iterate (iterate_device);
  74
  75   return ret;
  76 }
  77
  78 static grub_err_t
  79 grub_fs_uuid_open (const char *name, grub_disk_t disk)
  80 {
  81   grub_device_t dev;
  82
  83   if (grub_strncmp (name, "UUID=", sizeof ("UUID=")-1))
  84     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a UUID virtual volume");
  85
  86   dev = search_fs_uuid (name + sizeof ("UUID=") - 1, &disk->id);
  87   if (! dev)
  88     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no matching UUID found");
  89
  90   disk->total_sectors = dev->disk->total_sectors;
  91   disk->has_partitions = 0;
  92   if (dev->disk->partition)
  93     {
  94       disk->partition = grub_malloc (sizeof (*disk->partition));
  95       if (disk->partition)
  96         grub_memcpy (disk->partition, dev->disk->partition,
  97                      sizeof (*disk->partition));
  98     }
  99   else
 100     disk->partition = NULL;
 101
 102   disk->data = dev;
 103
 104   return GRUB_ERR_NONE;
 105 }
 106
 107 static void
 108 grub_fs_uuid_close (grub_disk_t disk __attribute((unused)))
 109 {
 110   grub_device_t parent = disk->data;
 111   grub_device_close (parent);
 112 }
 113
 114 static grub_err_t
 115 grub_fs_uuid_read (grub_disk_t disk, grub_disk_addr_t sector,
 116                    grub_size_t size, char *buf)
 117 {
 118   grub_device_t parent = disk->data;
 119   return parent->disk->dev->read (parent->disk, sector, size, buf);
 120 }
 121
 122 static grub_err_t
 123 grub_fs_uuid_write (grub_disk_t disk, grub_disk_addr_t sector,
 124                     grub_size_t size, const char *buf)
 125 {
 126   grub_device_t parent = disk->data;
 127   return parent->disk->dev->write (parent->disk, sector, size, buf);
 128 }
 129
 130 static struct grub_disk_dev grub_fs_uuid_dev =
 131   {
 132     .name = "fs_uuid",
 133     .id = GRUB_DISK_DEVICE_UUID_ID,
 134     .open = grub_fs_uuid_open,
 135     .close = grub_fs_uuid_close,
 136     .read = grub_fs_uuid_read,
 137     .write = grub_fs_uuid_write,
 138     .next = 0
 139   };
 140
 141 GRUB_MOD_INIT(fs_uuid)
 142 {
 143   grub_disk_dev_register (&grub_fs_uuid_dev);
 144 }
 145
 146 GRUB_MOD_FINI(fs_uuid)
 147 {
 148   grub_disk_dev_unregister (&grub_fs_uuid_dev);
 149 }