arch/all-pc/boot/grub2-aros/grub-core/disk/memdisk.c

   1 /* memdisk.c - Access embedded memory disk.  */
   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 GRUB_MOD_LICENSE ("GPLv3+");
  28
  29 static char *memdisk_addr;
  30 static grub_off_t memdisk_size = 0;
  31
  32 static int
  33 grub_memdisk_iterate (int (*hook) (const char *name),
  34                       grub_disk_pull_t pull)
  35 {
  36   if (pull != GRUB_DISK_PULL_NONE)
  37     return 0;
  38
  39   return hook ("memdisk");
  40 }
  41
  42 static grub_err_t
  43 grub_memdisk_open (const char *name, grub_disk_t disk)
  44 {
  45   if (grub_strcmp (name, "memdisk"))
  46       return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a memdisk");
  47
  48   disk->total_sectors = memdisk_size / GRUB_DISK_SECTOR_SIZE;
  49   disk->id = (unsigned long) "mdsk";
  50
  51   return GRUB_ERR_NONE;
  52 }
  53
  54 static void
  55 grub_memdisk_close (grub_disk_t disk __attribute((unused)))
  56 {
  57 }
  58
  59 static grub_err_t
  60 grub_memdisk_read (grub_disk_t disk __attribute((unused)), grub_disk_addr_t sector,
  61                     grub_size_t size, char *buf)
  62 {
  63   grub_memcpy (buf, memdisk_addr + (sector << GRUB_DISK_SECTOR_BITS), size << GRUB_DISK_SECTOR_BITS);
  64   return 0;
  65 }
  66
  67 static grub_err_t
  68 grub_memdisk_write (grub_disk_t disk __attribute((unused)), grub_disk_addr_t sector,
  69                      grub_size_t size, const char *buf)
  70 {
  71   grub_memcpy (memdisk_addr + (sector << GRUB_DISK_SECTOR_BITS), buf, size << GRUB_DISK_SECTOR_BITS);
  72   return 0;
  73 }
  74
  75 static struct grub_disk_dev grub_memdisk_dev =
  76   {
  77     .name = "memdisk",
  78     .id = GRUB_DISK_DEVICE_MEMDISK_ID,
  79     .iterate = grub_memdisk_iterate,
  80     .open = grub_memdisk_open,
  81     .close = grub_memdisk_close,
  82     .read = grub_memdisk_read,
  83     .write = grub_memdisk_write,
  84     .next = 0
  85   };
  86
  87 GRUB_MOD_INIT(memdisk)
  88 {
  89   struct grub_module_header *header;
  90   FOR_MODULES (header)
  91     if (header->type == OBJ_TYPE_MEMDISK)
  92       {
  93         char *memdisk_orig_addr;
  94         memdisk_orig_addr = (char *) header + sizeof (struct grub_module_header);
  95
  96         grub_dprintf ("memdisk", "Found memdisk image at %p\n", memdisk_orig_addr);
  97
  98         memdisk_size = header->size - sizeof (struct grub_module_header);
  99         memdisk_addr = grub_malloc (memdisk_size);
 100
 101         grub_dprintf ("memdisk", "Copying memdisk image to dynamic memory\n");
 102         grub_memmove (memdisk_addr, memdisk_orig_addr, memdisk_size);
 103
 104         grub_disk_dev_register (&grub_memdisk_dev);
 105         break;
 106       }
 107 }
 108
 109 GRUB_MOD_FINI(memdisk)
 110 {
 111   if (! memdisk_size)
 112     return;
 113   grub_free (memdisk_addr);
 114   grub_disk_dev_unregister (&grub_memdisk_dev);
 115 }