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 #ifndef GRUB_UTIL
  38 static grub_dl_t my_mod;
  39 #endif
  40
  41 \f
  42
  43 static grub_err_t
  44 gpt_partition_map_iterate (grub_disk_t disk,
  45                            int (*hook) (grub_disk_t disk,
  46                                         const grub_partition_t partition))
  47 {
  48   struct grub_partition part;
  49   struct grub_gpt_header gpt;
  50   struct grub_gpt_partentry entry;
  51   struct grub_disk raw;
  52   struct grub_pc_partition_mbr mbr;
  53   grub_uint64_t entries;
  54   unsigned int i;
  55   int last_offset = 0;
  56
  57   /* Enforce raw disk access.  */
  58   raw = *disk;
  59   raw.partition = 0;
  60
  61   /* Read the protective MBR.  */
  62   if (grub_disk_read (&raw, 0, 0, sizeof (mbr), (char *) &mbr))
  63     return grub_errno;
  64
  65   /* Check if it is valid.  */
  66   if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
  67     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
  68
  69   /* Make sure the MBR is a protective MBR and not a normal MBR.  */
  70   if (mbr.entries[0].type != GRUB_PC_PARTITION_TYPE_GPT_DISK)
  71     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
  72
  73   /* Read the GPT header.  */
  74   if (grub_disk_read (&raw, 1, 0, sizeof (gpt), (char *) &gpt))
  75     return grub_errno;
  76
  77   if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)))
  78     return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
  79
  80   grub_dprintf ("gpt", "Read a valid GPT header\n");
  81
  82   entries = grub_le_to_cpu64 (gpt.partitions);
  83   for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
  84     {
  85       if (grub_disk_read (&raw, entries, last_offset,
  86                           sizeof (entry), (char *) &entry))
  87         return grub_errno;
  88
  89       if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
  90                        sizeof (grub_gpt_partition_type_empty)))
  91         {
  92           /* Calculate the first block and the size of the partition.  */
  93           part.start = grub_le_to_cpu64 (entry.start);
  94           part.len = (grub_le_to_cpu64 (entry.end)
  95                       - grub_le_to_cpu64 (entry.start) + 1);
  96           part.offset = entries;
  97           part.index = i;
  98           part.partmap = &grub_gpt_partition_map;
  99           part.data = &entry;
 100
 101           grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n",
 102                         i, part.start, part.len);
 103
 104           if (hook (disk, &part))
 105             return grub_errno;
 106         }
 107
 108       last_offset += grub_le_to_cpu32 (gpt.partentry_size);
 109       if (last_offset == GRUB_DISK_SECTOR_SIZE)
 110         {
 111           last_offset = 0;
 112           entries++;
 113         }
 114     }
 115
 116   return 0;
 117 }
 118
 119
 120 static grub_partition_t
 121 gpt_partition_map_probe (grub_disk_t disk, const char *str)
 122 {
 123   grub_partition_t p = 0;
 124   int partnum = 0;
 125   char *s = (char *) str;
 126
 127   auto int find_func (grub_disk_t d, const grub_partition_t partition);
 128
 129   int find_func (grub_disk_t d __attribute__ ((unused)),
 130                  const grub_partition_t partition)
 131     {
 132       if (partnum == partition->index)
 133         {
 134           p = (grub_partition_t) grub_malloc (sizeof (*p));
 135           if (! p)
 136             return 1;
 137
 138           grub_memcpy (p, partition, sizeof (*p));
 139           return 1;
 140         }
 141
 142       return 0;
 143     }
 144
 145   /* Get the partition number.  */
 146   partnum = grub_strtoul (s, 0, 10) - 1;
 147   if (grub_errno)
 148     {
 149       grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
 150       return 0;
 151     }
 152
 153   if (gpt_partition_map_iterate (disk, find_func))
 154     goto fail;
 155
 156   return p;
 157
 158  fail:
 159   grub_free (p);
 160   return 0;
 161 }
 162
 163
 164 static char *
 165 gpt_partition_map_get_name (const grub_partition_t p)
 166 {
 167   char *name;
 168
 169   name = grub_malloc (13);
 170   if (! name)
 171     return 0;
 172
 173   grub_sprintf (name, "%d", p->index + 1);
 174   return name;
 175 }
 176
 177 \f
 178 /* Partition map type.  */
 179 static struct grub_partition_map grub_gpt_partition_map =
 180   {
 181     .name = "gpt_partition_map",
 182     .iterate = gpt_partition_map_iterate,
 183     .probe = gpt_partition_map_probe,
 184     .get_name = gpt_partition_map_get_name
 185   };
 186
 187 GRUB_MOD_INIT(gpt_partition_map)
 188 {
 189   grub_partition_map_register (&grub_gpt_partition_map);
 190 #ifndef GRUB_UTIL
 191   my_mod = mod;
 192 #endif
 193 }
 194
 195 GRUB_MOD_FINI(gpt_partition_map)
 196 {
 197   grub_partition_map_unregister (&grub_gpt_partition_map);
 198 }