extras/volume_id/lib/iso9660.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program 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
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef _GNU_SOURCE
  21 #define _GNU_SOURCE 1
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30
  31 #include "libvolume_id.h"
  32 #include "libvolume_id-private.h"
  33
  34 #define ISO_SUPERBLOCK_OFFSET           0x8000
  35 #define ISO_SECTOR_SIZE                 0x800
  36 #define ISO_VD_OFFSET                   (ISO_SUPERBLOCK_OFFSET + ISO_SECTOR_SIZE)
  37 #define ISO_VD_PRIMARY                  0x1
  38 #define ISO_VD_SUPPLEMENTARY            0x2
  39 #define ISO_VD_END                      0xff
  40 #define ISO_VD_MAX                      16
  41
  42 struct iso_volume_descriptor {
  43         uint8_t         type;
  44         uint8_t         id[5];
  45         uint8_t         version;
  46         uint8_t         flags;
  47         uint8_t         system_id[32];
  48         uint8_t         volume_id[32];
  49         uint8_t         unused[8];
  50         uint8_t         space_size[8];
  51         uint8_t         escape_sequences[8];
  52 } PACKED;
  53
  54 struct high_sierra_volume_descriptor {
  55         uint8_t         foo[8];
  56         uint8_t         type;
  57         uint8_t         id[5];
  58         uint8_t         version;
  59 } PACKED;
  60
  61 int volume_id_probe_iso9660(struct volume_id *id, uint64_t off, uint64_t size)
  62 {
  63         uint8_t *buf;
  64         struct iso_volume_descriptor *is;
  65         struct high_sierra_volume_descriptor *hs;
  66
  67         info("probing at offset 0x%llx\n", (unsigned long long) off);
  68
  69         buf = volume_id_get_buffer(id, off + ISO_SUPERBLOCK_OFFSET, 0x200);
  70         if (buf == NULL)
  71                 return -1;
  72
  73         is = (struct iso_volume_descriptor *) buf;
  74
  75         if (memcmp(is->id, "CD001", 5) == 0) {
  76                 int vd_offset;
  77                 int i;
  78
  79                 dbg("read label from PVD\n");
  80                 volume_id_set_label_raw(id, is->volume_id, 32);
  81                 volume_id_set_label_string(id, is->volume_id, 32);
  82
  83                 dbg("looking for SVDs\n");
  84                 vd_offset = ISO_VD_OFFSET;
  85                 for (i = 0; i < ISO_VD_MAX; i++) {
  86                         uint8_t svd_label[64];
  87
  88                         is = (struct iso_volume_descriptor *) volume_id_get_buffer(id, off + vd_offset, 0x200);
  89                         if (is == NULL || is->type == ISO_VD_END)
  90                                 break;
  91                         if (is->type != ISO_VD_SUPPLEMENTARY)
  92                                 continue;
  93
  94                         dbg("found SVD at offset 0x%llx\n", (unsigned long long) (off + vd_offset));
  95                         if (memcmp(is->escape_sequences, "%/@", 3) == 0||
  96                             memcmp(is->escape_sequences, "%/C", 3) == 0||
  97                             memcmp(is->escape_sequences, "%/E", 3) == 0) {
  98                                 dbg("Joliet extension found\n");
  99                                 volume_id_set_unicode16(svd_label, sizeof(svd_label), is->volume_id, BE, 32);
 100                                 if (memcmp(id->label, svd_label, 16) == 0) {
 101                                         dbg("SVD label is identical, use the possibly longer PVD one\n");
 102                                         break;
 103                                 }
 104
 105                                 volume_id_set_label_raw(id, is->volume_id, 32);
 106                                 volume_id_set_label_string(id, svd_label, 32);
 107                                 strcpy(id->type_version, "Joliet Extension");
 108                                 goto found;
 109                         }
 110                         vd_offset += ISO_SECTOR_SIZE;
 111                 }
 112                 goto found;
 113         }
 114
 115         hs = (struct high_sierra_volume_descriptor *) buf;
 116
 117         if (memcmp(hs->id, "CDROM", 5) == 0) {
 118                 strcpy(id->type_version, "High Sierra");
 119                 goto found;
 120         }
 121
 122         return -1;
 123
 124 found:
 125         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 126         id->type = "iso9660";
 127
 128         return 0;
 129 }