diff options
Diffstat (limited to 'util-linux/volume_id/msdos.c')
| -rw-r--r-- | util-linux/volume_id/msdos.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/util-linux/volume_id/msdos.c b/util-linux/volume_id/msdos.c new file mode 100644 index 0000000..b4b6711 --- /dev/null +++ b/util-linux/volume_id/msdos.c @@ -0,0 +1,196 @@ +/* + * 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; +} |