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/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "volume_id_internal.h"
struct msdos_partition_entry {
uint8_t boot_ind;
uint8_t head;
uint8_t sector;
uint8_t cyl;
uint8_t sys_ind;
uint8_t end_head;
uint8_t end_sector;
uint8_t end_cyl;
uint32_t start_sect;
uint32_t nr_sects;
} __attribute__((packed));
#define MSDOS_MAGIC "\x55\xaa"
#define MSDOS_PARTTABLE_OFFSET 0x1be
#define MSDOS_SIG_OFF 0x1fe
#define BSIZE 0x200
#define DOS_EXTENDED_PARTITION 0x05
#define LINUX_EXTENDED_PARTITION 0x85
#define WIN98_EXTENDED_PARTITION 0x0f
#define LINUX_RAID_PARTITION 0xfd
#define is_extended(type) \
(type == DOS_EXTENDED_PARTITION || \
type == WIN98_EXTENDED_PARTITION || \
type == LINUX_EXTENDED_PARTITION)
#define is_raid(type) \
(type == LINUX_RAID_PARTITION)
int volume_id_probe_msdos_part_table(struct volume_id *id, uint64_t off)
{
const uint8_t *buf;
int i;
uint64_t poff;
uint64_t plen;
uint64_t extended = 0;
uint64_t current;
uint64_t next;
int limit;
int empty = 1;
struct msdos_partition_entry *part;
struct volume_id_partition *p;
dbg("probing at offset 0x%llx", (unsigned long long) off);
buf = volume_id_get_buffer(id, off, 0x200);
if (buf == NULL)
return -1;
if (memcmp(&buf[MSDOS_SIG_OFF], MSDOS_MAGIC, 2) != 0)
return -1;
/* check flags on all entries for a valid partition table */
part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
for (i = 0; i < 4; i++) {
if (part[i].boot_ind != 0 &&
part[i].boot_ind != 0x80)
return -1;
if (part[i].nr_sects != 0)
empty = 0;
}
if (empty == 1)
return -1;
if (id->partitions != NULL)
free(id->partitions);
id->partitions = malloc(VOLUME_ID_PARTITIONS_MAX *
sizeof(struct volume_id_partition));
if (id->partitions == NULL)
return -1;
memset(id->partitions, 0x00,
VOLUME_ID_PARTITIONS_MAX * sizeof(struct volume_id_partition));
for (i = 0; i < 4; i++) {
poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
if (plen == 0)
continue;
p = &id->partitions[i];
p->partition_type_raw = part[i].sys_ind;
if (is_extended(part[i].sys_ind)) {
dbg("found extended partition at 0x%llx", (unsigned long long) poff);
volume_id_set_usage_part(p, VOLUME_ID_PARTITIONTABLE);
p->type = "msdos_extended_partition";
if (extended == 0)
extended = off + poff;
} else {
dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
if (is_raid(part[i].sys_ind))
volume_id_set_usage_part(p, VOLUME_ID_RAID);
else
volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
}
p->off = off + poff;
p->len = plen;
id->partition_count = i+1;
}
next = extended;
current = extended;
limit = 50;
/* follow extended partition chain and add data partitions */
while (next != 0) {
if (limit-- == 0) {
dbg("extended chain limit reached");
break;
}
buf = volume_id_get_buffer(id, current, 0x200);
if (buf == NULL)
break;
part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
if (memcmp(&buf[MSDOS_SIG_OFF], MSDOS_MAGIC, 2) != 0)
break;
next = 0;
for (i = 0; i < 4; i++) {
poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
if (plen == 0)
continue;
if (is_extended(part[i].sys_ind)) {
dbg("found extended partition at 0x%llx", (unsigned long long) poff);
if (next == 0)
next = extended + poff;
} else {
dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
/* we always start at the 5th entry */
while (id->partition_count < 4)
volume_id_set_usage_part(&id->partitions[id->partition_count++], VOLUME_ID_UNUSED);
p = &id->partitions[id->partition_count];
if (is_raid(part[i].sys_ind))
volume_id_set_usage_part(p, VOLUME_ID_RAID);
else
volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
p->off = current + poff;
p->len = plen;
id->partition_count++;
p->partition_type_raw = part[i].sys_ind;
if (id->partition_count >= VOLUME_ID_PARTITIONS_MAX) {
dbg("too many partitions");
next = 0;
}
}
}
current = next;
}
volume_id_set_usage(id, VOLUME_ID_PARTITIONTABLE);
id->type = "msdos_partition_table";
return 0;
}
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