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 //kbuild:### lib-$(CONFIG_FEATURE_VOLUMEID_MSDOS) += msdos.o
  22
  23 //config:
  24 //config:### config FEATURE_VOLUMEID_MSDOS
  25 //config:###    bool "msdos filesystem"
  26 //config:###    default y
  27 //config:###    depends on VOLUMEID
  28 //config:###    help
  29 //config:###      TODO
  30 //config:
  31
  32 #include "volume_id_internal.h"
  33
  34 struct msdos_partition_entry {
  35         uint8_t         boot_ind;
  36         uint8_t         head;
  37         uint8_t         sector;
  38         uint8_t         cyl;
  39         uint8_t         sys_ind;
  40         uint8_t         end_head;
  41         uint8_t         end_sector;
  42         uint8_t         end_cyl;
  43         uint32_t        start_sect;
  44         uint32_t        nr_sects;
  45 } PACKED;
  46
  47 #define MSDOS_PARTTABLE_OFFSET          0x1be
  48 #define MSDOS_SIG_OFF                   0x1fe
  49 #define BSIZE                           0x200
  50 #define DOS_EXTENDED_PARTITION          0x05
  51 #define LINUX_EXTENDED_PARTITION        0x85
  52 #define WIN98_EXTENDED_PARTITION        0x0f
  53 #define LINUX_RAID_PARTITION            0xfd
  54 #define is_extended(type) \
  55         (type == DOS_EXTENDED_PARTITION ||      \
  56          type == WIN98_EXTENDED_PARTITION ||    \
  57          type == LINUX_EXTENDED_PARTITION)
  58 #define is_raid(type) \
  59         (type == LINUX_RAID_PARTITION)
  60
  61 int FAST_FUNC volume_id_probe_msdos_part_table(struct volume_id *id, uint64_t off)
  62 {
  63         const uint8_t *buf;
  64         int i;
  65         uint64_t poff;
  66         uint64_t plen;
  67         uint64_t extended = 0;
  68         uint64_t current;
  69         uint64_t next;
  70         int limit;
  71         int empty = 1;
  72         struct msdos_partition_entry *part;
  73         struct volume_id_partition *p;
  74
  75         dbg("probing at offset 0x%llx", (unsigned long long) off);
  76
  77         buf = volume_id_get_buffer(id, off, 0x200);
  78         if (buf == NULL)
  79                 return -1;
  80
  81         if (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
  82                 return -1;
  83
  84         /* check flags on all entries for a valid partition table */
  85         part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
  86         for (i = 0; i < 4; i++) {
  87                 if (part[i].boot_ind != 0
  88                  && part[i].boot_ind != 0x80
  89                 ) {
  90                         return -1;
  91                 }
  92
  93                 if (part[i].nr_sects != 0)
  94                         empty = 0;
  95         }
  96         if (empty == 1)
  97                 return -1;
  98
  99         if (id->partitions != NULL)
 100                 free(id->partitions);
 101         id->partitions = xzalloc(VOLUME_ID_PARTITIONS_MAX *
 102                                 sizeof(struct volume_id_partition));
 103
 104         for (i = 0; i < 4; i++) {
 105                 poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
 106                 plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
 107
 108                 if (plen == 0)
 109                         continue;
 110
 111                 p = &id->partitions[i];
 112
 113 //              p->pt_type_raw = part[i].sys_ind;
 114
 115                 if (is_extended(part[i].sys_ind)) {
 116                         dbg("found extended partition at 0x%llx", (unsigned long long) poff);
 117 //                      volume_id_set_usage_part(p, VOLUME_ID_PARTITIONTABLE);
 118 //                      p->type = "msdos_extended_partition";
 119                         if (extended == 0)
 120                                 extended = off + poff;
 121                 } else {
 122                         dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
 123                                 part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
 124
 125 //                      if (is_raid(part[i].sys_ind))
 126 //                              volume_id_set_usage_part(p, VOLUME_ID_RAID);
 127 //                      else
 128 //                              volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
 129                 }
 130
 131 //              p->pt_off = off + poff;
 132 //              p->pt_len = plen;
 133                 id->partition_count = i+1;
 134         }
 135
 136         next = extended;
 137         current = extended;
 138         limit = 50;
 139
 140         /* follow extended partition chain and add data partitions */
 141         while (next != 0) {
 142                 if (limit-- == 0) {
 143                         dbg("extended chain limit reached");
 144                         break;
 145                 }
 146
 147                 buf = volume_id_get_buffer(id, current, 0x200);
 148                 if (buf == NULL)
 149                         break;
 150
 151                 part = (struct msdos_partition_entry*) &buf[MSDOS_PARTTABLE_OFFSET];
 152
 153                 if (buf[MSDOS_SIG_OFF] != 0x55 || buf[MSDOS_SIG_OFF + 1] != 0xaa)
 154                         break;
 155
 156                 next = 0;
 157
 158                 for (i = 0; i < 4; i++) {
 159                         poff = (uint64_t) le32_to_cpu(part[i].start_sect) * BSIZE;
 160                         plen = (uint64_t) le32_to_cpu(part[i].nr_sects) * BSIZE;
 161
 162                         if (plen == 0)
 163                                 continue;
 164
 165                         if (is_extended(part[i].sys_ind)) {
 166                                 dbg("found extended partition at 0x%llx", (unsigned long long) poff);
 167                                 if (next == 0)
 168                                         next = extended + poff;
 169                         } else {
 170                                 dbg("found 0x%x data partition at 0x%llx, len 0x%llx",
 171                                         part[i].sys_ind, (unsigned long long) poff, (unsigned long long) plen);
 172
 173                                 /* we always start at the 5th entry */
 174 //                              while (id->partition_count < 4)
 175 //                                      volume_id_set_usage_part(&id->partitions[id->partition_count++], VOLUME_ID_UNUSED);
 176                                 if (id->partition_count < 4)
 177                                         id->partition_count = 4;
 178
 179                                 p = &id->partitions[id->partition_count];
 180
 181 //                              if (is_raid(part[i].sys_ind))
 182 //                                      volume_id_set_usage_part(p, VOLUME_ID_RAID);
 183 //                              else
 184 //                                      volume_id_set_usage_part(p, VOLUME_ID_UNPROBED);
 185
 186 //                              p->pt_off = current + poff;
 187 //                              p->pt_len = plen;
 188                                 id->partition_count++;
 189
 190 //                              p->pt_type_raw = part[i].sys_ind;
 191
 192                                 if (id->partition_count >= VOLUME_ID_PARTITIONS_MAX) {
 193                                         dbg("too many partitions");
 194                                         next = 0;
 195                                 }
 196                         }
 197                 }
 198
 199                 current = next;
 200         }
 201
 202 //      volume_id_set_usage(id, VOLUME_ID_PARTITIONTABLE);
 203 //      id->type = "msdos_partition_table";
 204
 205         return 0;
 206 }