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