1
/* pc.c - Read PC style partition tables. */
3
* GRUB -- GRand Unified Bootloader
4
* Copyright (C) 2002,2004,2005,2006,2007,2008,2009 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/partition.h>
21
#include <grub/msdos_partition.h>
22
#include <grub/disk.h>
24
#include <grub/misc.h>
27
static struct grub_partition_map grub_msdos_partition_map;
30
/* Parse the partition representation in STR and return a partition. */
31
static grub_partition_t
32
grub_partition_parse (const char *str)
35
struct grub_msdos_partition *pcdata;
37
char *s = (char *) str;
39
p = (grub_partition_t) grub_malloc (sizeof (*p));
43
pcdata = (struct grub_msdos_partition *) grub_malloc (sizeof (*pcdata));
48
p->partmap = &grub_msdos_partition_map;
50
/* Initialize some of the fields with invalid values. */
51
pcdata->bsd_part = pcdata->dos_type = pcdata->bsd_type = p->index = -1;
53
/* Get the DOS partition number. The number is counted from one for
54
the user interface, and from zero internally. */
55
pcdata->dos_part = grub_strtoul (s, &s, 0) - 1;
59
/* Not found. Maybe only a BSD label is specified. */
60
pcdata->dos_part = -1;
61
grub_errno = GRUB_ERR_NONE;
68
if (*s >= 'a' && *s <= 'h')
70
pcdata->bsd_part = *s - 'a';
78
if (pcdata->dos_part == -1 && pcdata->bsd_part == -1)
86
grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
91
pc_partition_map_iterate (grub_disk_t disk,
92
int (*hook) (grub_disk_t disk,
93
const grub_partition_t partition))
95
struct grub_partition p;
96
struct grub_msdos_partition pcdata;
97
struct grub_msdos_partition_mbr mbr;
98
struct grub_msdos_partition_disk_label label;
101
grub_disk_addr_t lastaddr;
103
/* Enforce raw disk access. */
108
pcdata.ext_offset = 0;
109
pcdata.dos_part = -1;
111
p.partmap = &grub_msdos_partition_map;
113
/* Any value different than `p.offset' will satisfy the check during
115
lastaddr = !p.offset;
120
struct grub_msdos_partition_entry *e;
123
if (grub_disk_read (&raw, p.offset, 0, sizeof (mbr), &mbr))
126
/* This is our loop-detection algorithm. It works the following way:
127
It saves last position which was a power of two. Then it compares the
128
saved value with a current one. This way it's guaranteed that the loop
129
will be broken by at most third walk.
131
if (labeln && lastaddr == p.offset)
132
return grub_error (GRUB_ERR_BAD_PART_TABLE, "loop detected");
135
if ((labeln & (labeln - 1)) == 0)
138
/* Check if it is valid. */
139
if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
140
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
142
for (i = 0; i < 4; i++)
143
if (mbr.entries[i].flag & 0x7f)
144
return grub_error (GRUB_ERR_BAD_PART_TABLE, "bad boot flag");
146
/* Analyze DOS partitions. */
147
for (p.index = 0; p.index < 4; p.index++)
149
e = mbr.entries + p.index;
151
p.start = p.offset + grub_le_to_cpu32 (e->start);
152
p.len = grub_le_to_cpu32 (e->length);
153
pcdata.bsd_part = -1;
154
pcdata.dos_type = e->type;
155
pcdata.bsd_type = -1;
157
grub_dprintf ("partition",
158
"partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
159
p.index, e->flag, pcdata.dos_type,
160
(unsigned long long) p.start,
161
(unsigned long long) p.len);
163
/* If this is a GPT partition, this MBR is just a dummy. */
164
if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
165
return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
167
/* If this partition is a normal one, call the hook. */
168
if (! grub_msdos_partition_is_empty (e->type)
169
&& ! grub_msdos_partition_is_extended (e->type))
176
/* Check if this is a BSD partition. */
177
if (grub_msdos_partition_is_bsd (e->type))
179
/* Check if the BSD label is within the DOS partition. */
180
if (p.len <= GRUB_PC_PARTITION_BSD_LABEL_SECTOR)
182
grub_dprintf ("partition", "no space for disk label\n");
185
/* Read the BSD label. */
186
if (grub_disk_read (&raw,
188
+ GRUB_PC_PARTITION_BSD_LABEL_SECTOR),
194
/* Check if it is valid. */
196
!= grub_cpu_to_le32 (GRUB_PC_PARTITION_BSD_LABEL_MAGIC))
198
grub_dprintf ("partition",
199
"invalid disk label magic 0x%x on partition %d\n",
200
label.magic, p.index);
203
for (pcdata.bsd_part = 0;
204
pcdata.bsd_part < grub_cpu_to_le16 (label.num_partitions);
207
struct grub_msdos_partition_bsd_entry *be
208
= label.entries + pcdata.bsd_part;
210
p.start = grub_le_to_cpu32 (be->offset);
211
p.len = grub_le_to_cpu32 (be->size);
212
pcdata.bsd_type = be->fs_type;
214
if (be->fs_type != GRUB_PC_PARTITION_BSD_TYPE_UNUSED)
220
else if (pcdata.dos_part < 4)
221
/* If this partition is a logical one, shouldn't increase the
226
/* Find an extended partition. */
227
for (i = 0; i < 4; i++)
231
if (grub_msdos_partition_is_extended (e->type))
233
p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start);
234
if (! pcdata.ext_offset)
235
pcdata.ext_offset = p.offset;
241
/* If no extended partition, the end. */
251
static grub_partition_t
252
pc_partition_map_probe (grub_disk_t disk, const char *str)
255
struct grub_msdos_partition *pcdata;
257
auto int find_func (grub_disk_t d, const grub_partition_t partition);
259
int find_func (grub_disk_t d __attribute__ ((unused)),
260
const grub_partition_t partition)
262
struct grub_msdos_partition *partdata = partition->data;
264
if ((pcdata->dos_part == partdata->dos_part || pcdata->dos_part == -1)
265
&& pcdata->bsd_part == partdata->bsd_part)
267
grub_memcpy (p, partition, sizeof (*p));
269
grub_memcpy (pcdata, partdata, sizeof (*pcdata));
276
p = grub_partition_parse (str);
281
pc_partition_map_iterate (disk, find_func);
287
grub_error (GRUB_ERR_BAD_DEVICE, "no such partition");
301
pc_partition_map_get_name (const grub_partition_t p)
303
struct grub_msdos_partition *pcdata = p->data;
305
if (pcdata->bsd_part < 0)
306
return grub_xasprintf ("%d", pcdata->dos_part + 1);
307
else if (pcdata->dos_part < 0)
308
return grub_xasprintf ("%c", pcdata->bsd_part + 'a');
310
return grub_xasprintf ("%d,%c", pcdata->dos_part + 1,
311
pcdata->bsd_part + 'a');
315
/* Partition map type. */
316
static struct grub_partition_map grub_msdos_partition_map =
318
.name = "part_msdos",
319
.iterate = pc_partition_map_iterate,
320
.probe = pc_partition_map_probe,
321
.get_name = pc_partition_map_get_name
324
GRUB_MOD_INIT(pc_partition_map)
326
grub_partition_map_register (&grub_msdos_partition_map);
329
GRUB_MOD_FINI(pc_partition_map)
331
grub_partition_map_unregister (&grub_msdos_partition_map);