2009-07-20 Joe Auricchio <jauricchio@gmail.com>
[grub2/phcoder.git] / partmap / gpt.c
blobd646d41b8c28c903ff33801865f10bbcef10760b
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.
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.
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.
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/>.
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>
28 static grub_uint8_t grub_gpt_magic[8] =
30 0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
33 static const grub_gpt_part_type_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
35 static struct grub_partition_map grub_gpt_partition_map;
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))
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_pc_partition_mbr mbr;
49 grub_uint64_t entries;
50 unsigned int i;
51 int last_offset = 0;
53 /* Enforce raw disk access. */
54 raw = *disk;
55 raw.partition = 0;
57 /* Read the protective MBR. */
58 if (grub_disk_read (&raw, 0, 0, sizeof (mbr), &mbr))
59 return grub_errno;
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");
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");
69 /* Read the GPT header. */
70 if (grub_disk_read (&raw, 1, 0, sizeof (gpt), &gpt))
71 return grub_errno;
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");
76 grub_dprintf ("gpt", "Read a valid GPT header\n");
78 entries = grub_le_to_cpu64 (gpt.partitions);
79 for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
81 if (grub_disk_read (&raw, entries, last_offset,
82 sizeof (entry), &entry))
83 return grub_errno;
85 if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
86 sizeof (grub_gpt_partition_type_empty)))
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;
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);
101 if (hook (disk, &part))
102 return 1;
105 last_offset += grub_le_to_cpu32 (gpt.partentry_size);
106 if (last_offset == GRUB_DISK_SECTOR_SIZE)
108 last_offset = 0;
109 entries++;
113 return 0;
117 static grub_partition_t
118 gpt_partition_map_probe (grub_disk_t disk, const char *str)
120 grub_partition_t p = 0;
121 int partnum = 0;
122 char *s = (char *) str;
124 auto int find_func (grub_disk_t d, const grub_partition_t partition);
126 int find_func (grub_disk_t d __attribute__ ((unused)),
127 const grub_partition_t partition)
129 if (partnum == partition->index)
131 p = (grub_partition_t) grub_malloc (sizeof (*p));
132 if (! p)
133 return 1;
135 grub_memcpy (p, partition, sizeof (*p));
136 return 1;
139 return 0;
142 /* Get the partition number. */
143 partnum = grub_strtoul (s, 0, 10) - 1;
144 if (grub_errno)
146 grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
147 return 0;
150 gpt_partition_map_iterate (disk, find_func);
151 if (grub_errno)
152 goto fail;
154 return p;
156 fail:
157 grub_free (p);
158 return 0;
162 static char *
163 gpt_partition_map_get_name (const grub_partition_t p)
165 char *name;
167 name = grub_malloc (13);
168 if (! name)
169 return 0;
171 grub_sprintf (name, "%d", p->index + 1);
172 return name;
176 /* Partition map type. */
177 static struct grub_partition_map grub_gpt_partition_map =
179 .name = "gpt_partition_map",
180 .iterate = gpt_partition_map_iterate,
181 .probe = gpt_partition_map_probe,
182 .get_name = gpt_partition_map_get_name
185 GRUB_MOD_INIT(gpt_partition_map)
187 grub_partition_map_register (&grub_gpt_partition_map);
190 GRUB_MOD_FINI(gpt_partition_map)
192 grub_partition_map_unregister (&grub_gpt_partition_map);