/* pc.c - Read PC style partition tables. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2004,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see .
*/
#include
#include
#include
#include
#include
#include
static struct grub_partition_map grub_msdos_partition_map;
/* Parse the partition representation in STR and return a partition. */
static grub_partition_t
grub_partition_parse (const char *str)
{
grub_partition_t p;
struct grub_msdos_partition *pcdata;
char *s = (char *) str;
p = (grub_partition_t) grub_malloc (sizeof (*p));
if (! p)
return 0;
pcdata = (struct grub_msdos_partition *) grub_malloc (sizeof (*pcdata));
if (! pcdata)
goto fail;
p->data = pcdata;
p->partmap = &grub_msdos_partition_map;
/* Initialize some of the fields with invalid values. */
pcdata->bsd_part = pcdata->dos_type = pcdata->bsd_type = p->index = -1;
/* Get the DOS partition number. The number is counted from one for
the user interface, and from zero internally. */
pcdata->dos_part = grub_strtoul (s, &s, 0) - 1;
if (grub_errno)
{
/* Not found. Maybe only a BSD label is specified. */
pcdata->dos_part = -1;
grub_errno = GRUB_ERR_NONE;
}
else if (*s == ',')
s++;
if (*s)
{
if (*s >= 'a' && *s <= 'h')
{
pcdata->bsd_part = *s - 'a';
s++;
}
if (*s)
goto fail;
}
if (pcdata->dos_part == -1 && pcdata->bsd_part == -1)
goto fail;
return p;
fail:
grub_free (p);
grub_free (pcdata);
grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
return 0;
}
static grub_err_t
pc_partition_map_iterate (grub_disk_t disk,
int (*hook) (grub_disk_t disk,
const grub_partition_t partition))
{
struct grub_partition p;
struct grub_msdos_partition pcdata;
struct grub_msdos_partition_mbr mbr;
struct grub_msdos_partition_disk_label label;
struct grub_disk raw;
int labeln = 0;
grub_disk_addr_t lastaddr;
/* Enforce raw disk access. */
raw = *disk;
raw.partition = 0;
p.offset = 0;
pcdata.ext_offset = 0;
pcdata.dos_part = -1;
p.data = &pcdata;
p.partmap = &grub_msdos_partition_map;
/* Any value different than `p.offset' will satisfy the check during
first loop. */
lastaddr = !p.offset;
while (1)
{
int i;
struct grub_msdos_partition_entry *e;
/* Read the MBR. */
if (grub_disk_read (&raw, p.offset, 0, sizeof (mbr), &mbr))
goto finish;
/* This is our loop-detection algorithm. It works the following way:
It saves last position which was a power of two. Then it compares the
saved value with a current one. This way it's guaranteed that the loop
will be broken by at most third walk.
*/
if (labeln && lastaddr == p.offset)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "loop detected");
labeln++;
if ((labeln & (labeln - 1)) == 0)
lastaddr = p.offset;
/* Check if it is valid. */
if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
for (i = 0; i < 4; i++)
if (mbr.entries[i].flag & 0x7f)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "bad boot flag");
/* Analyze DOS partitions. */
for (p.index = 0; p.index < 4; p.index++)
{
e = mbr.entries + p.index;
p.start = p.offset + grub_le_to_cpu32 (e->start);
p.len = grub_le_to_cpu32 (e->length);
pcdata.bsd_part = -1;
pcdata.dos_type = e->type;
pcdata.bsd_type = -1;
grub_dprintf ("partition",
"partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
p.index, e->flag, pcdata.dos_type,
(unsigned long long) p.start,
(unsigned long long) p.len);
/* If this is a GPT partition, this MBR is just a dummy. */
if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
/* If this partition is a normal one, call the hook. */
if (! grub_msdos_partition_is_empty (e->type)
&& ! grub_msdos_partition_is_extended (e->type))
{
pcdata.dos_part++;
if (hook (disk, &p))
return 1;
/* Check if this is a BSD partition. */
if (grub_msdos_partition_is_bsd (e->type))
{
/* Check if the BSD label is within the DOS partition. */
if (p.len <= GRUB_PC_PARTITION_BSD_LABEL_SECTOR)
{
grub_dprintf ("partition", "no space for disk label\n");
continue;
}
/* Read the BSD label. */
if (grub_disk_read (&raw,
(p.start
+ GRUB_PC_PARTITION_BSD_LABEL_SECTOR),
0,
sizeof (label),
&label))
goto finish;
/* Check if it is valid. */
if (label.magic
!= grub_cpu_to_le32 (GRUB_PC_PARTITION_BSD_LABEL_MAGIC))
{
grub_dprintf ("partition",
"invalid disk label magic 0x%x on partition %d\n",
label.magic, p.index);
continue;
}
for (pcdata.bsd_part = 0;
pcdata.bsd_part < grub_cpu_to_le16 (label.num_partitions);
pcdata.bsd_part++)
{
struct grub_msdos_partition_bsd_entry *be
= label.entries + pcdata.bsd_part;
p.start = grub_le_to_cpu32 (be->offset);
p.len = grub_le_to_cpu32 (be->size);
pcdata.bsd_type = be->fs_type;
if (be->fs_type != GRUB_PC_PARTITION_BSD_TYPE_UNUSED)
if (hook (disk, &p))
return 1;
}
}
}
else if (pcdata.dos_part < 4)
/* If this partition is a logical one, shouldn't increase the
partition number. */
pcdata.dos_part++;
}
/* Find an extended partition. */
for (i = 0; i < 4; i++)
{
e = mbr.entries + i;
if (grub_msdos_partition_is_extended (e->type))
{
p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start);
if (! pcdata.ext_offset)
pcdata.ext_offset = p.offset;
break;
}
}
/* If no extended partition, the end. */
if (i == 4)
break;
}
finish:
return grub_errno;
}
static grub_partition_t
pc_partition_map_probe (grub_disk_t disk, const char *str)
{
grub_partition_t p;
struct grub_msdos_partition *pcdata;
auto int find_func (grub_disk_t d, const grub_partition_t partition);
int find_func (grub_disk_t d __attribute__ ((unused)),
const grub_partition_t partition)
{
struct grub_msdos_partition *partdata = partition->data;
if ((pcdata->dos_part == partdata->dos_part || pcdata->dos_part == -1)
&& pcdata->bsd_part == partdata->bsd_part)
{
grub_memcpy (p, partition, sizeof (*p));
p->data = pcdata;
grub_memcpy (pcdata, partdata, sizeof (*pcdata));
return 1;
}
return 0;
}
p = grub_partition_parse (str);
if (! p)
return 0;
pcdata = p->data;
pc_partition_map_iterate (disk, find_func);
if (grub_errno)
goto fail;
if (p->index < 0)
{
grub_error (GRUB_ERR_BAD_DEVICE, "no such partition");
goto fail;
}
return p;
fail:
grub_free (p);
grub_free (pcdata);
return 0;
}
static char *
pc_partition_map_get_name (const grub_partition_t p)
{
char *name;
struct grub_msdos_partition *pcdata = p->data;
name = grub_malloc (13);
if (! name)
return 0;
if (pcdata->bsd_part < 0)
grub_sprintf (name, "%d", pcdata->dos_part + 1);
else if (pcdata->dos_part < 0)
grub_sprintf (name, "%c", pcdata->bsd_part + 'a');
else
grub_sprintf (name, "%d,%c", pcdata->dos_part + 1, pcdata->bsd_part + 'a');
return name;
}
/* Partition map type. */
static struct grub_partition_map grub_msdos_partition_map =
{
.name = "part_msdos",
.iterate = pc_partition_map_iterate,
.probe = pc_partition_map_probe,
.get_name = pc_partition_map_get_name
};
GRUB_MOD_INIT(pc_partition_map)
{
grub_partition_map_register (&grub_msdos_partition_map);
}
GRUB_MOD_FINI(pc_partition_map)
{
grub_partition_map_unregister (&grub_msdos_partition_map);
}