extras/volume_id/volume_id/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 "volume_id.h"
  27 #include "logging.h"
  28 #include "util.h"
  29 #include "iso9660.h"
  30
  31 #define ISO_SUPERBLOCK_OFFSET           0x8000
  32 #define ISO_SECTOR_SIZE                 0x800
  33 #define ISO_VD_OFFSET                   (ISO_SUPERBLOCK_OFFSET + ISO_SECTOR_SIZE)
  34 #define ISO_VD_PRIMARY                  0x1
  35 #define ISO_VD_SUPPLEMENTARY            0x2
  36 #define ISO_VD_END                      0xff
  37 #define ISO_VD_MAX                      16
  38
  39 struct iso_volume_descriptor {
  40         uint8_t         vd_type;
  41         uint8_t         vd_id[5];
  42         uint8_t         vd_version;
  43         uint8_t         flags;
  44         uint8_t         system_id[32];
  45         uint8_t         volume_id[32];
  46         uint8_t         unused[8];
  47         uint8_t         space_size[8];
  48         uint8_t         escape_sequences[8];
  49 } __attribute__((__packed__));
  50
  51 struct high_sierra_volume_descriptor {
  52         uint8_t         foo[8];
  53         uint8_t         type;
  54         uint8_t         id[4];
  55         uint8_t         version;
  56 } __attribute__((__packed__));
  57
  58 int volume_id_probe_iso9660(struct volume_id *id, uint64_t off)
  59 {
  60         uint8_t *buf;
  61         struct iso_volume_descriptor *is;
  62         struct high_sierra_volume_descriptor *hs;
  63
  64         dbg("probing at offset 0x%llx", (unsigned long long) off);
  65
  66         buf = volume_id_get_buffer(id, off + ISO_SUPERBLOCK_OFFSET, 0x200);
  67         if (buf == NULL)
  68                 return -1;
  69
  70         is = (struct iso_volume_descriptor *) buf;
  71
  72         if (memcmp(is->vd_id, "CD001", 5) == 0) {
  73                 int vd_offset;
  74                 int i;
  75
  76                 dbg("read label from PVD");
  77                 volume_id_set_label_raw(id, is->volume_id, 32);
  78                 volume_id_set_label_string(id, is->volume_id, 32);
  79
  80                 dbg("looking for SVDs");
  81                 vd_offset = ISO_VD_OFFSET;
  82                 for (i = 0; i < ISO_VD_MAX; i++) {
  83                         uint8_t svd_label[64];
  84
  85                         is = (struct iso_volume_descriptor *) volume_id_get_buffer(id, off + vd_offset, 0x200);
  86                         if (is == NULL || is->vd_type == ISO_VD_END)
  87                                 break;
  88                         if (is->vd_type != ISO_VD_SUPPLEMENTARY)
  89                                 continue;
  90
  91                         dbg("found SVD at offset 0x%llx", (unsigned long long) (off + vd_offset));
  92                         if (memcmp(is->escape_sequences, "%/@", 3) == 0||
  93                             memcmp(is->escape_sequences, "%/C", 3) == 0||
  94                             memcmp(is->escape_sequences, "%/E", 3) == 0) {
  95                                 dbg("Joliet extension found");
  96                                 volume_id_set_unicode16((char *)svd_label, sizeof(svd_label), is->volume_id, BE, 32);
  97                                 if (memcmp(id->label, svd_label, 16) == 0) {
  98                                         dbg("SVD label is identical, use the possibly longer PVD one");
  99                                         break;
 100                                 }
 101
 102                                 volume_id_set_label_raw(id, is->volume_id, 32);
 103                                 volume_id_set_label_string(id, svd_label, 32);
 104                                 strcpy(id->type_version, "Joliet Extension");
 105                                 goto found;
 106                         }
 107                         vd_offset += ISO_SECTOR_SIZE;
 108                 }
 109                 goto found;
 110         }
 111
 112         hs = (struct high_sierra_volume_descriptor *) buf;
 113
 114         if (memcmp(hs->id, "CDROM", 5) == 0) {
 115                 strcpy(id->type_version, "High Sierra");
 116                 goto found;
 117         }
 118
 119         return -1;
 120
 121 found:
 122         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 123         id->type = "iso9660";
 124
 125         return 0;
 126 }