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/msdos_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_disk raw;
  48   struct grub_msdos_partition_mbr mbr;
  49   grub_uint64_t entries;
  50   unsigned int i;
  51   int last_offset = 0;
  52
  53   /* Enforce raw disk access.  */
  54   raw = *disk;
  55   raw.partition = 0;
  56
  57   /* Read the protective MBR.  */
  58   if (grub_disk_read (&raw, 0, 0, sizeof (mbr), &mbr))
  59     return grub_errno;
  60
  61   /* Check if it is valid.  */
  62   if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
  63     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
  64
  65   /* Make sure the MBR is a protective MBR and not a normal MBR.  */
  66   if (mbr.entries[0].type != GRUB_PC_PARTITION_TYPE_GPT_DISK)
  67     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
  68
  69   /* Read the GPT header.  */
  70   if (grub_disk_read (&raw, 1, 0, sizeof (gpt), &gpt))
  71     return grub_errno;
  72
  73   if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)))
  74     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
  75
  76   grub_dprintf ("gpt", "Read a valid GPT header\n");
  77
  78   entries = grub_le_to_cpu64 (gpt.partitions);
  79   for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
  80     {
  81       if (grub_disk_read (&raw, entries, last_offset,
  82                           sizeof (entry), &entry))
  83         return grub_errno;
  84
  85       if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
  86                        sizeof (grub_gpt_partition_type_empty)))
  87         {
  88           /* Calculate the first block and the size of the partition.  */
  89           part.start = grub_le_to_cpu64 (entry.start);
  90           part.len = (grub_le_to_cpu64 (entry.end)
  91                       - grub_le_to_cpu64 (entry.start) + 1);
  92           part.offset = entries;
  93           part.index = i;
  94           part.partmap = &grub_gpt_partition_map;
  95           part.data = &entry;
  96
  97           grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n", i,
  98                         (unsigned long long) part.start,
  99                         (unsigned long long) part.len);
 100
 101           if (hook (disk, &part))
 102             return 1;
 103         }
 104
 105       last_offset += grub_le_to_cpu32 (gpt.partentry_size);
 106       if (last_offset == GRUB_DISK_SECTOR_SIZE)
 107         {
 108           last_offset = 0;
 109           entries++;
 110         }
 111     }
 112
 113   return 0;
 114 }
 115
 116
 117 static grub_partition_t
 118 gpt_partition_map_probe (grub_disk_t disk, const char *str)
 119 {
 120   grub_partition_t p = 0;
 121   int partnum = 0;
 122   char *s = (char *) str;
 123
 124   auto int find_func (grub_disk_t d, const grub_partition_t partition);
 125
 126   int find_func (grub_disk_t d __attribute__ ((unused)),
 127                  const grub_partition_t partition)
 128     {
 129       if (partnum == partition->index)
 130         {
 131           p = (grub_partition_t) grub_malloc (sizeof (*p));
 132           if (! p)
 133             return 1;
 134
 135           grub_memcpy (p, partition, sizeof (*p));
 136           return 1;
 137         }
 138
 139       return 0;
 140     }
 141
 142   /* Get the partition number.  */
 143   partnum = grub_strtoul (s, 0, 10) - 1;
 144   if (grub_errno)
 145     {
 146       grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
 147       return 0;
 148     }
 149
 150   gpt_partition_map_iterate (disk, find_func);
 151   if (grub_errno)
 152     goto fail;
 153
 154   return p;
 155
 156  fail:
 157   grub_free (p);
 158   return 0;
 159 }
 160
 161
 162 static char *
 163 gpt_partition_map_get_name (const grub_partition_t p)
 164 {
 165   char *name;
 166
 167   name = grub_malloc (13);
 168   if (! name)
 169     return 0;
 170
 171   grub_sprintf (name, "%d", p->index + 1);
 172   return name;
 173 }
 174
 175 \f
 176 /* Partition map type.  */
 177 static struct grub_partition_map grub_gpt_partition_map =
 178   {
 179     .name = "part_gpt",
 180     .iterate = gpt_partition_map_iterate,
 181     .probe = gpt_partition_map_probe,
 182     .get_name = gpt_partition_map_get_name
 183   };
 184
 185 GRUB_MOD_INIT(gpt_partition_map)
 186 {
 187   grub_partition_map_register (&grub_gpt_partition_map);
 188 }
 189
 190 GRUB_MOD_FINI(gpt_partition_map)
 191 {
 192   grub_partition_map_unregister (&grub_gpt_partition_map);
 193 }