partmap/gpt.c

   1 /* gpt.c - Read GUID Partition Tables (GPT).  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2005,2006,2007,2008  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/misc.h>
  22 #include <grub/mm.h>
  23 #include <grub/partition.h>
  24 #include <grub/dl.h>
  25 #include <grub/pc_partition.h>
  26 #include <grub/gpt_partition.h>
  27
  28 static grub_uint8_t grub_gpt_magic[8] =
  29   {
  30     0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
  31   };
  32
  33 static const grub_gpt_part_type_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
  34
  35 static struct grub_partition_map grub_gpt_partition_map;
  36
  37 \f
  38
  39 static grub_err_t
  40 gpt_partition_map_iterate (grub_disk_t disk,
  41                            int (*hook) (grub_disk_t disk,
  42                                         const grub_partition_t partition))
  43 {
  44   struct grub_partition part;
  45   struct grub_gpt_header gpt;
  46   struct grub_gpt_partentry entry;
  47   struct grub_pc_partition_mbr mbr;
  48   grub_uint64_t entries;
  49   unsigned int i;
  50   int last_offset = 0;
  51
  52   /* Read the protective MBR.  */
  53   if (grub_disk_read (disk, 0, 0, sizeof (mbr), &mbr))
  54     return grub_errno;
  55
  56   /* Check if it is valid.  */
  57   if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
  58     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
  59
  60   /* Make sure the MBR is a protective MBR and not a normal MBR.  */
  61   if (mbr.entries[0].type != GRUB_PC_PARTITION_TYPE_GPT_DISK)
  62     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
  63
  64   /* Read the GPT header.  */
  65   if (grub_disk_read (disk, 1, 0, sizeof (gpt), &gpt))
  66     return grub_errno;
  67
  68   if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)))
  69     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
  70
  71   grub_dprintf ("gpt", "Read a valid GPT header\n");
  72
  73   entries = grub_le_to_cpu64 (gpt.partitions);
  74   part.data = grub_malloc (sizeof (entry));
  75   for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
  76     {
  77       if (grub_disk_read (disk, entries, last_offset,
  78                           sizeof (entry), &entry))
  79         {
  80           grub_free (part.data);
  81           return grub_errno;
  82         }
  83
  84       if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
  85                        sizeof (grub_gpt_partition_type_empty)))
  86         {
  87           /* Calculate the first block and the size of the partition.  */
  88           part.start = grub_le_to_cpu64 (entry.start);
  89           part.len = (grub_le_to_cpu64 (entry.end)
  90                       - grub_le_to_cpu64 (entry.start) + 1);
  91           part.offset = entries;
  92           part.number = i;
  93           part.partmap = &grub_gpt_partition_map;
  94           grub_memcpy (part.data, &entry, sizeof (entry));
  95
  96           grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n", i,
  97                         (unsigned long long) part.start,
  98                         (unsigned long long) part.len);
  99
 100           if (hook (disk, &part))
 101             return 1;
 102         }
 103
 104       last_offset += grub_le_to_cpu32 (gpt.partentry_size);
 105       if (last_offset == GRUB_DISK_SECTOR_SIZE)
 106         {
 107           last_offset = 0;
 108           entries++;
 109         }
 110     }
 111   grub_free (part.data);
 112
 113   return 0;
 114 }
 115
 116 \f
 117 /* Partition map type.  */
 118 static struct grub_partition_map grub_gpt_partition_map =
 119   {
 120     .name = "gpt_partition_map",
 121     .iterate = gpt_partition_map_iterate,
 122   };
 123
 124 GRUB_MOD_INIT(gpt_partition_map)
 125 {
 126   grub_partition_map_register (&grub_gpt_partition_map);
 127 }
 128
 129 GRUB_MOD_FINI(gpt_partition_map)
 130 {
 131   grub_partition_map_unregister (&grub_gpt_partition_map);
 132 }