source: MondoRescue/branches/3.3/mindi-busybox/util-linux/volume_id/unused_msdos.c@ 3865

/*
 * 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;
}