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 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 #ifndef _GNU_SOURCE
  22 #define _GNU_SOURCE 1
  23 #endif
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include <config.h>
  27 #endif
  28
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <string.h>
  33 #include <errno.h>
  34 #include <ctype.h>
  35 #include <asm/types.h>
  36
  37 #include "volume_id.h"
  38 #include "logging.h"
  39 #include "util.h"
  40 #include "iso9660.h"
  41
  42 #define ISO_SUPERBLOCK_OFFSET           0x8000
  43 #define ISO_SECTOR_SIZE                 0x800
  44 #define ISO_VD_OFFSET                   (ISO_SUPERBLOCK_OFFSET + ISO_SECTOR_SIZE)
  45 #define ISO_VD_PRIMARY                  0x1
  46 #define ISO_VD_SUPPLEMENTARY            0x2
  47 #define ISO_VD_END                      0xff
  48 #define ISO_VD_MAX                      16
  49
  50 struct iso_volume_descriptor {
  51         __u8    vd_type;
  52         __u8    vd_id[5];
  53         __u8    vd_version;
  54         __u8    flags;
  55         __u8    system_id[32];
  56         __u8    volume_id[32];
  57         __u8    unused[8];
  58         __u8    space_size[8];
  59         __u8    escape_sequences[8];
  60 } __attribute__((__packed__));
  61
  62 struct high_sierra_volume_descriptor {
  63         __u8    foo[8];
  64         __u8    type;
  65         __u8    id[4];
  66         __u8    version;
  67 } __attribute__((__packed__));
  68
  69 int volume_id_probe_iso9660(struct volume_id *id, __u64 off)
  70 {
  71         __u8 *buf;
  72         struct iso_volume_descriptor *is;
  73         struct high_sierra_volume_descriptor *hs;
  74
  75         dbg("probing at offset 0x%llx", (unsigned long long) off);
  76
  77         buf = volume_id_get_buffer(id, off + ISO_SUPERBLOCK_OFFSET, 0x200);
  78         if (buf == NULL)
  79                 return -1;
  80
  81         is = (struct iso_volume_descriptor *) buf;
  82
  83         if (memcmp(is->vd_id, "CD001", 5) == 0) {
  84                 int vd_offset;
  85                 int i;
  86
  87                 dbg("read label from PVD");
  88                 volume_id_set_label_raw(id, is->volume_id, 32);
  89                 volume_id_set_label_string(id, is->volume_id, 32);
  90
  91                 dbg("looking for SVDs");
  92                 vd_offset = ISO_VD_OFFSET;
  93                 for (i = 0; i < ISO_VD_MAX; i++) {
  94                         char svd_label[64];
  95
  96                         is = (struct iso_volume_descriptor *) volume_id_get_buffer(id, off + vd_offset, 0x200);
  97                         if (is == NULL || is->vd_type == ISO_VD_END)
  98                                 break;
  99                         if (is->vd_type != ISO_VD_SUPPLEMENTARY)
 100                                 continue;
 101
 102                         dbg("found SVD at offset 0x%llx", (unsigned long long) (off + vd_offset));
 103                         if (memcmp(is->escape_sequences, "%/@", 3) == 0||
 104                             memcmp(is->escape_sequences, "%/C", 3) == 0||
 105                             memcmp(is->escape_sequences, "%/E", 3) == 0) {
 106                                 dbg("Joliet extension found");
 107                                 volume_id_set_unicode16(svd_label, sizeof(svd_label), is->volume_id, BE, 32);
 108                                 if (memcmp(id->label, svd_label, 16) == 0) {
 109                                         dbg("SVD label is identical, use the possibly longer PVD one");
 110                                         break;
 111                                 }
 112
 113                                 volume_id_set_label_raw(id, is->volume_id, 32);
 114                                 volume_id_set_label_string(id, svd_label, 32);
 115                                 strcpy(id->type_version, "Joliet Extension");
 116                                 goto found;
 117                         }
 118                         vd_offset += ISO_SECTOR_SIZE;
 119                 }
 120                 goto found;
 121         }
 122
 123         hs = (struct high_sierra_volume_descriptor *) buf;
 124
 125         if (memcmp(hs->id, "CDROM", 5) == 0) {
 126                 strcpy(id->type_version, "High Sierra");
 127                 goto found;
 128         }
 129
 130         return -1;
 131
 132 found:
 133         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 134         id->type = "iso9660";
 135
 136         return 0;
 137 }