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