grub/partmap/gpt.c
robertmh 8516d2a8e1 2008-07-04 Robert Millan <rmh@aybabtu.com>
This fixes a performance issue when pc & gpt partmap iterators
        didn't abort iteration even after our hook found what it was
        looking for (often causing expensive probes of non-existant drives).

        Some callers relied on previous buggy behaviour, since they would
        rise an error when their own hooks caused early abortion of its
        iteration.

        * kern/device.c (grub_device_open): Improve error message.
        * disk/lvm.c (grub_lvm_open): Likewise.
        * disk/raid.c (grub_raid_open): Likewise.

        * partmap/pc.c (pc_partition_map_iterate): Abort parent iteration
        when hook requests it, independently of grub_errno.
        (pc_partition_map_probe): Do not fail when find_func() caused
        early abortion of pc_partition_map_iterate().

        * partmap/gpt.c (gpt_partition_map_iterate): Abort parent iteration
        when hook requests it, independently of grub_errno.
        (gpt_partition_map_probe): Do not fail when find_func() caused
        early abortion of gpt_partition_map_iterate().

        * kern/partition.c (grub_partition_iterate): Abort parent iteration
        when hook requests it, independently of grub_errno.  Do not fail when
        part_map_iterate_hook() caused early abortion of p->iterate().

        * util/biosdisk.c (grub_util_biosdisk_get_grub_dev): Do not fail
        when grub_partition_iterate() returned with non-zero.
2008-07-03 22:56:43 +00:00

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/* gpt.c - Read GUID Partition Tables (GPT). */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2005,2006,2007,2008 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 <http://www.gnu.org/licenses/>.
*/
#include <grub/disk.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/partition.h>
#include <grub/dl.h>
#include <grub/pc_partition.h>
#include <grub/gpt_partition.h>
static grub_uint8_t grub_gpt_magic[8] =
{
0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
};
static const grub_gpt_part_type_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
static struct grub_partition_map grub_gpt_partition_map;
#ifndef GRUB_UTIL
static grub_dl_t my_mod;
#endif
static grub_err_t
gpt_partition_map_iterate (grub_disk_t disk,
int (*hook) (grub_disk_t disk,
const grub_partition_t partition))
{
struct grub_partition part;
struct grub_gpt_header gpt;
struct grub_gpt_partentry entry;
struct grub_disk raw;
struct grub_pc_partition_mbr mbr;
grub_uint64_t entries;
unsigned int i;
int last_offset = 0;
/* Enforce raw disk access. */
raw = *disk;
raw.partition = 0;
/* Read the protective MBR. */
if (grub_disk_read (&raw, 0, 0, sizeof (mbr), (char *) &mbr))
return grub_errno;
/* 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");
/* Make sure the MBR is a protective MBR and not a normal MBR. */
if (mbr.entries[0].type != GRUB_PC_PARTITION_TYPE_GPT_DISK)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
/* Read the GPT header. */
if (grub_disk_read (&raw, 1, 0, sizeof (gpt), (char *) &gpt))
return grub_errno;
if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)))
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
grub_dprintf ("gpt", "Read a valid GPT header\n");
entries = grub_le_to_cpu64 (gpt.partitions);
for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
{
if (grub_disk_read (&raw, entries, last_offset,
sizeof (entry), (char *) &entry))
return grub_errno;
if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
sizeof (grub_gpt_partition_type_empty)))
{
/* Calculate the first block and the size of the partition. */
part.start = grub_le_to_cpu64 (entry.start);
part.len = (grub_le_to_cpu64 (entry.end)
- grub_le_to_cpu64 (entry.start) + 1);
part.offset = entries;
part.index = i;
part.partmap = &grub_gpt_partition_map;
part.data = &entry;
grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n", i,
(unsigned long long) part.start,
(unsigned long long) part.len);
if (hook (disk, &part))
return 1;
}
last_offset += grub_le_to_cpu32 (gpt.partentry_size);
if (last_offset == GRUB_DISK_SECTOR_SIZE)
{
last_offset = 0;
entries++;
}
}
return 0;
}
static grub_partition_t
gpt_partition_map_probe (grub_disk_t disk, const char *str)
{
grub_partition_t p = 0;
int partnum = 0;
char *s = (char *) str;
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)
{
if (partnum == partition->index)
{
p = (grub_partition_t) grub_malloc (sizeof (*p));
if (! p)
return 1;
grub_memcpy (p, partition, sizeof (*p));
return 1;
}
return 0;
}
/* Get the partition number. */
partnum = grub_strtoul (s, 0, 10) - 1;
if (grub_errno)
{
grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
return 0;
}
gpt_partition_map_iterate (disk, find_func);
if (grub_errno)
goto fail;
return p;
fail:
grub_free (p);
return 0;
}
static char *
gpt_partition_map_get_name (const grub_partition_t p)
{
char *name;
name = grub_malloc (13);
if (! name)
return 0;
grub_sprintf (name, "%d", p->index + 1);
return name;
}
/* Partition map type. */
static struct grub_partition_map grub_gpt_partition_map =
{
.name = "gpt_partition_map",
.iterate = gpt_partition_map_iterate,
.probe = gpt_partition_map_probe,
.get_name = gpt_partition_map_get_name
};
GRUB_MOD_INIT(gpt_partition_map)
{
grub_partition_map_register (&grub_gpt_partition_map);
#ifndef GRUB_UTIL
my_mod = mod;
#endif
}
GRUB_MOD_FINI(gpt_partition_map)
{
grub_partition_map_unregister (&grub_gpt_partition_map);
}