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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
*/
//kbuild:### lib-$(CONFIG_FEATURE_VOLUMEID_MSDOS) += msdos.o
//config:
//config:### config FEATURE_VOLUMEID_MSDOS
//config:### bool "msdos filesystem"
//config:### default y
//config:### depends on VOLUMEID
//config:### help
//config:### TODO
//config:
#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;
} PACKED;
#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 FAST_FUNC 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 (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
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 = xzalloc(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->pt_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->pt_off = off + poff;
// p->pt_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 (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
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);
if (id->partition_count < 4)
id->partition_count = 4;
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->pt_off = current + poff;
// p->pt_len = plen;
id->partition_count++;
// p->pt_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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