disk/fs_file.c

   1 /* fs_file.c - Access partition by a file it contains.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2009  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/file.h>
  23 #include <grub/misc.h>
  24 #include <grub/mm.h>
  25 #include <grub/partition.h>
  26
  27 static grub_device_t
  28 search_fs_file (const char *key, unsigned long *count)
  29 {
  30   char *filename = NULL;
  31   grub_device_t ret = NULL;
  32   *count = 0;
  33
  34   auto int iterate_device (const char *name);
  35   int iterate_device (const char *name)
  36   {
  37     int len;
  38     grub_file_t file;
  39
  40     (*count)++;
  41
  42     len = grub_strlen (name) + 2 + grub_strlen (key) + 1;
  43     filename = grub_realloc (filename, len);
  44     if (! filename)
  45       return 1;
  46
  47     grub_sprintf (filename, "(%s)%s", name, key);
  48     file = grub_file_open (filename);
  49     if (file)
  50       {
  51         grub_file_close (file);
  52         ret = grub_device_open (name);
  53         return 1;
  54       }
  55
  56     grub_errno = GRUB_ERR_NONE;
  57     return 0;
  58   }
  59
  60   grub_device_iterate (iterate_device);
  61   grub_free (filename);
  62
  63   return ret;
  64 }
  65
  66 static grub_err_t
  67 grub_fs_file_open (const char *name, grub_disk_t disk)
  68 {
  69   grub_device_t dev;
  70
  71   if (grub_strncmp (name, "FILE=", sizeof ("FILE=") - 1))
  72     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a FILE virtual volume");
  73
  74   dev = search_fs_file (name + sizeof ("FILE=") - 1, &disk->id);
  75   if (! dev)
  76     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no matching file found");
  77
  78   disk->total_sectors = dev->disk->total_sectors;
  79   disk->has_partitions = 0;
  80   if (dev->disk->partition)
  81     {
  82       disk->partition = grub_malloc (sizeof (*disk->partition));
  83       if (disk->partition)
  84         grub_memcpy (disk->partition, dev->disk->partition,
  85                      sizeof (*disk->partition));
  86     }
  87   else
  88     disk->partition = NULL;
  89
  90   disk->data = dev;
  91
  92   return GRUB_ERR_NONE;
  93 }
  94
  95 static void
  96 grub_fs_file_close (grub_disk_t disk)
  97 {
  98   grub_device_t parent = disk->data;
  99   grub_device_close (parent);
 100 }
 101
 102 static grub_err_t
 103 grub_fs_file_read (grub_disk_t disk, grub_disk_addr_t sector,
 104                    grub_size_t size, char *buf)
 105 {
 106   grub_device_t parent = disk->data;
 107   return parent->disk->dev->read (parent->disk, sector, size, buf);
 108 }
 109
 110 static grub_err_t
 111 grub_fs_file_write (grub_disk_t disk, grub_disk_addr_t sector,
 112                     grub_size_t size, const char *buf)
 113 {
 114   grub_device_t parent = disk->data;
 115   return parent->disk->dev->write (parent->disk, sector, size, buf);
 116 }
 117
 118 static struct grub_disk_dev grub_fs_file_dev = {
 119   .name = "fs_file",
 120   .id = GRUB_DISK_DEVICE_FILE_ID,
 121   .open = grub_fs_file_open,
 122   .close = grub_fs_file_close,
 123   .read = grub_fs_file_read,
 124   .write = grub_fs_file_write,
 125   .next = 0
 126 };
 127
 128 GRUB_MOD_INIT (fs_file)
 129 {
 130   grub_disk_dev_register (&grub_fs_file_dev);
 131 }
 132
 133 GRUB_MOD_FINI (fs_file)
 134 {
 135   grub_disk_dev_unregister (&grub_fs_file_dev);
 136 }