release/src/router/busybox/util-linux/volume_id/unused_msdos.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      This library is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU Lesser General Public
   8  *      License as published by the Free Software Foundation; either
   9  *      version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *      This library is distributed in the hope that it will be useful,
  12  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  *      Lesser General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU Lesser General Public
  17  *      License along with this library; if not, write to the Free Software
  18  *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 #include "volume_id_internal.h"
  22
  23 struct msdos_partition_entry {
  24         uint8_t         boot_ind;
  25         uint8_t         head;
  26         uint8_t         sector;
  27         uint8_t         cyl;
  28         uint8_t         sys_ind;
  29         uint8_t         end_head;
  30         uint8_t         end_sector;
  31         uint8_t         end_cyl;
  32         uint32_t        start_sect;
  33         uint32_t        nr_sects;
  34 } PACKED;
  35
  36 #define MSDOS_PARTTABLE_OFFSET          0x1be
  37 #define MSDOS_SIG_OFF                   0x1fe
  38 #define BSIZE                           0x200
  39 #define DOS_EXTENDED_PARTITION          0x05
  40 #define LINUX_EXTENDED_PARTITION        0x85
  41 #define WIN98_EXTENDED_PARTITION        0x0f
  42 #define LINUX_RAID_PARTITION            0xfd
  43 #define is_extended(type) \
  44         (type == DOS_EXTENDED_PARTITION ||      \
  45          type == WIN98_EXTENDED_PARTITION ||    \
  46          type == LINUX_EXTENDED_PARTITION)
  47 #define is_raid(type) \
  48         (type == LINUX_RAID_PARTITION)
  49
  50 int FAST_FUNC volume_id_probe_msdos_part_table(struct volume_id *id, uint64_t off)
  51 {
  52         const uint8_t *buf;
  53         int i;
  54         uint64_t poff;
  55         uint64_t plen;
  56         uint64_t extended = 0;
  57         uint64_t current;
  58         uint64_t next;
  59         int limit;
  60         int empty = 1;
  61         struct msdos_partition_entry *part;
  62         struct volume_id_partition *p;
  63
  64         dbg("probing at offset 0x%llx", (unsigned long long) off);
  65
  66         buf = volume_id_get_buffer(id, off, 0x200);
  67         if (buf == NULL)
  68                 return -1;
  69
  70         if (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
  71                 return -1;
  72
  73         /* check flags on all entries for a valid partition table */
  74         part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
  75         for (i = 0; i < 4; i++) {
  76                 if (part[i].boot_ind != 0
  77                  && part[i].boot_ind != 0x80
  78                 ) {
  79                         return -1;
  80                 }
  81
  82                 if (part[i].nr_sects != 0)
  83                         empty = 0;
  84         }
  85         if (empty == 1)
  86                 return -1;
  87
  88         if (id->partitions != NULL)
  89                 free(id->partitions);
  90         id->partitions = xzalloc(VOLUME_ID_PARTITIONS_MAX *
  91                                 sizeof(struct volume_id_partition));
  92
  93         for (i = 0; i < 4; i++) {
  94                 poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
  95                 plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
  96
  97                 if (plen == 0)
  98                         continue;
  99
 100                 p = &id->partitions[i];
 101
 102 //              p->pt_type_raw = part[i].sys_ind;
 103
 104                 if (is_extended(part[i].sys_ind)) {
 105                         dbg("found extended partition at 0x%llx", (unsigned long long) poff);
 106 //                      volume_id_set_usage_part(p, VOLUME_ID_PARTITIONTABLE);
 107 //                      p->type = "msdos_extended_partition";
 108                         if (extended == 0)
 109                                 extended = off + poff;
 110                 } else {
 111                         dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
 112                                 part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
 113
 114 //                      if (is_raid(part[i].sys_ind))
 115 //                              volume_id_set_usage_part(p, VOLUME_ID_RAID);
 116 //                      else
 117 //                              volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
 118                 }
 119
 120 //              p->pt_off = off + poff;
 121 //              p->pt_len = plen;
 122                 id->partition_count = i+1;
 123         }
 124
 125         next = extended;
 126         current = extended;
 127         limit = 50;
 128
 129         /* follow extended partition chain and add data partitions */
 130         while (next != 0) {
 131                 if (limit-- == 0) {
 132                         dbg("extended chain limit reached");
 133                         break;
 134                 }
 135
 136                 buf = volume_id_get_buffer(id, current, 0x200);
 137                 if (buf == NULL)
 138                         break;
 139
 140                 part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
 141
 142                 if (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
 143                         break;
 144
 145                 next = 0;
 146
 147                 for (i = 0; i < 4; i++) {
 148                         poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
 149                         plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
 150
 151                         if (plen == 0)
 152                                 continue;
 153
 154                         if (is_extended(part[i].sys_ind)) {
 155                                 dbg("found extended partition at 0x%llx", (unsigned long long) poff);
 156                                 if (next == 0)
 157                                         next = extended + poff;
 158                         } else {
 159                                 dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
 160                                         part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
 161
 162                                 /* we always start at the 5th entry */
 163 //                              while (id->partition_count < 4)
 164 //                                      volume_id_set_usage_part(&id->partitions[id->partition_count++], VOLUME_ID_UNUSED);
 165                                 if (id->partition_count < 4)
 166                                         id->partition_count = 4;
 167
 168                                 p = &id->partitions[id->partition_count];
 169
 170 //                              if (is_raid(part[i].sys_ind))
 171 //                                      volume_id_set_usage_part(p, VOLUME_ID_RAID);
 172 //                              else
 173 //                                      volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
 174
 175 //                              p->pt_off = current + poff;
 176 //                              p->pt_len = plen;
 177                                 id->partition_count++;
 178
 179 //                              p->pt_type_raw = part[i].sys_ind;
 180
 181                                 if (id->partition_count >= VOLUME_ID_PARTITIONS_MAX) {
 182                                         dbg("too many partitions");
 183                                         next = 0;
 184                                 }
 185                         }
 186                 }
 187
 188                 current = next;
 189         }
 190
 191 //      volume_id_set_usage(id, VOLUME_ID_PARTITIONTABLE);
 192 //      id->type = "msdos_partition_table";
 193
 194         return 0;
 195 }