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 it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  */
  10
  11 #ifndef _GNU_SOURCE
  12 #define _GNU_SOURCE 1
  13 #endif
  14
  15 #ifdef HAVE_CONFIG_H
  16 #  include <config.h>
  17 #endif
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25
  26 #include "libvolume_id.h"
  27 #include "util.h"
  28
  29 #define ISO_SUPERBLOCK_OFFSET           0x8000
  30 #define ISO_SECTOR_SIZE                 0x800
  31 #define ISO_VD_OFFSET                   (ISO_SUPERBLOCK_OFFSET + ISO_SECTOR_SIZE)
  32 #define ISO_VD_PRIMARY                  0x1
  33 #define ISO_VD_SUPPLEMENTARY            0x2
  34 #define ISO_VD_END                      0xff
  35 #define ISO_VD_MAX                      16
  36
  37 struct iso_volume_descriptor {
  38         uint8_t         type;
  39         uint8_t         id[5];
  40         uint8_t         version;
  41         uint8_t         flags;
  42         uint8_t         system_id[32];
  43         uint8_t         volume_id[32];
  44         uint8_t         unused[8];
  45         uint8_t         space_size[8];
  46         uint8_t         escape_sequences[8];
  47 } PACKED;
  48
  49 struct high_sierra_volume_descriptor {
  50         uint8_t         foo[8];
  51         uint8_t         type;
  52         uint8_t         id[5];
  53         uint8_t         version;
  54 } PACKED;
  55
  56 int volume_id_probe_iso9660(struct volume_id *id, uint64_t off, uint64_t size)
  57 {
  58         uint8_t *buf;
  59         struct iso_volume_descriptor *is;
  60         struct high_sierra_volume_descriptor *hs;
  61
  62         info("probing at offset 0x%llx", (unsigned long long) off);
  63
  64         buf = volume_id_get_buffer(id, off + ISO_SUPERBLOCK_OFFSET, 0x200);
  65         if (buf == NULL)
  66                 return -1;
  67
  68         is = (struct iso_volume_descriptor *) buf;
  69
  70         if (memcmp(is->id, "CD001", 5) == 0) {
  71                 int vd_offset;
  72                 int i;
  73
  74                 dbg("read label from PVD");
  75                 volume_id_set_label_raw(id, is->volume_id, 32);
  76                 volume_id_set_label_string(id, is->volume_id, 32);
  77
  78                 dbg("looking for SVDs");
  79                 vd_offset = ISO_VD_OFFSET;
  80                 for (i = 0; i < ISO_VD_MAX; i++) {
  81                         uint8_t svd_label[64];
  82
  83                         is = (struct iso_volume_descriptor *) volume_id_get_buffer(id, off + vd_offset, 0x200);
  84                         if (is == NULL || is->type == ISO_VD_END)
  85                                 break;
  86                         if (is->type != ISO_VD_SUPPLEMENTARY)
  87                                 continue;
  88
  89                         dbg("found SVD at offset 0x%llx", (unsigned long long) (off + vd_offset));
  90                         if (memcmp(is->escape_sequences, "%/@", 3) == 0||
  91                             memcmp(is->escape_sequences, "%/C", 3) == 0||
  92                             memcmp(is->escape_sequences, "%/E", 3) == 0) {
  93                                 dbg("Joliet extension found");
  94                                 volume_id_set_unicode16(svd_label, sizeof(svd_label), is->volume_id, BE, 32);
  95                                 if (memcmp(id->label, svd_label, 16) == 0) {
  96                                         dbg("SVD label is identical, use the possibly longer PVD one");
  97                                         break;
  98                                 }
  99
 100                                 volume_id_set_label_raw(id, is->volume_id, 32);
 101                                 volume_id_set_label_string(id, svd_label, 32);
 102                                 strcpy(id->type_version, "Joliet Extension");
 103                                 goto found;
 104                         }
 105                         vd_offset += ISO_SECTOR_SIZE;
 106                 }
 107                 goto found;
 108         }
 109
 110         hs = (struct high_sierra_volume_descriptor *) buf;
 111
 112         if (memcmp(hs->id, "CDROM", 5) == 0) {
 113                 strcpy(id->type_version, "High Sierra");
 114                 goto found;
 115         }
 116
 117         return -1;
 118
 119 found:
 120         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 121         id->type = "iso9660";
 122
 123         return 0;
 124 }