extras/volume_id/volume_id/ntfs/ntfs.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 "ntfs.h"
  41
  42 #define MFT_RECORD_VOLUME                       3
  43 #define MFT_RECORD_ATTR_VOLUME_NAME             0x60
  44 #define MFT_RECORD_ATTR_VOLUME_INFO             0x70
  45 #define MFT_RECORD_ATTR_OBJECT_ID               0x40
  46 #define MFT_RECORD_ATTR_END                     0xffffffffu
  47
  48 int volume_id_probe_ntfs(struct volume_id *id, __u64 off)
  49 {
  50         struct ntfs_super_block {
  51                 __u8    jump[3];
  52                 __u8    oem_id[8];
  53                 __u16   bytes_per_sector;
  54                 __u8    sectors_per_cluster;
  55                 __u16   reserved_sectors;
  56                 __u8    fats;
  57                 __u16   root_entries;
  58                 __u16   sectors;
  59                 __u8    media_type;
  60                 __u16   sectors_per_fat;
  61                 __u16   sectors_per_track;
  62                 __u16   heads;
  63                 __u32   hidden_sectors;
  64                 __u32   large_sectors;
  65                 __u16   unused[2];
  66                 __u64   number_of_sectors;
  67                 __u64   mft_cluster_location;
  68                 __u64   mft_mirror_cluster_location;
  69                 __s8    cluster_per_mft_record;
  70                 __u8    reserved1[3];
  71                 __s8    cluster_per_index_record;
  72                 __u8    reserved2[3];
  73                 __u8    volume_serial[8];
  74                 __u16   checksum;
  75         } __attribute__((__packed__)) *ns;
  76
  77         struct master_file_table_record {
  78                 __u8    magic[4];
  79                 __u16   usa_ofs;
  80                 __u16   usa_count;
  81                 __u64   lsn;
  82                 __u16   sequence_number;
  83                 __u16   link_count;
  84                 __u16   attrs_offset;
  85                 __u16   flags;
  86                 __u32   bytes_in_use;
  87                 __u32   bytes_allocated;
  88         } __attribute__((__packed__)) *mftr;
  89
  90         struct file_attribute {
  91                 __u32   type;
  92                 __u32   len;
  93                 __u8    non_resident;
  94                 __u8    name_len;
  95                 __u16   name_offset;
  96                 __u16   flags;
  97                 __u16   instance;
  98                 __u32   value_len;
  99                 __u16   value_offset;
 100         } __attribute__((__packed__)) *attr;
 101
 102         struct volume_info {
 103                 __u64 reserved;
 104                 __u8 major_ver;
 105                 __u8 minor_ver;
 106         } __attribute__((__packed__)) *info;
 107
 108         unsigned int sector_size;
 109         unsigned int cluster_size;
 110         __u64 mft_cluster;
 111         __u64 mft_off;
 112         unsigned int mft_record_size;
 113         unsigned int attr_type;
 114         unsigned int attr_off;
 115         unsigned int attr_len;
 116         unsigned int val_off;
 117         unsigned int val_len;
 118         const __u8 *buf;
 119         const __u8 *val;
 120
 121         ns = (struct ntfs_super_block *) volume_id_get_buffer(id, off, 0x200);
 122         if (ns == NULL)
 123                 return -1;
 124
 125         if (strncmp(ns->oem_id, "NTFS", 4) != 0)
 126                 return -1;
 127
 128         volume_id_set_uuid(id, ns->volume_serial, UUID_NTFS);
 129
 130         sector_size = le16_to_cpu(ns->bytes_per_sector);
 131         cluster_size = ns->sectors_per_cluster * sector_size;
 132         mft_cluster = le64_to_cpu(ns->mft_cluster_location);
 133         mft_off = mft_cluster * cluster_size;
 134
 135         if (ns->cluster_per_mft_record < 0)
 136                 /* size = -log2(mft_record_size); normally 1024 Bytes */
 137                 mft_record_size = 1 << -ns->cluster_per_mft_record;
 138         else
 139                 mft_record_size = ns->cluster_per_mft_record * cluster_size;
 140
 141         dbg("sectorsize  0x%x", sector_size);
 142         dbg("clustersize 0x%x", cluster_size);
 143         dbg("mftcluster  %lli", mft_cluster);
 144         dbg("mftoffset  0x%llx", mft_off);
 145         dbg("cluster per mft_record  %i", ns->cluster_per_mft_record);
 146         dbg("mft record size  %i", mft_record_size);
 147
 148         buf = volume_id_get_buffer(id, off + mft_off + (MFT_RECORD_VOLUME * mft_record_size),
 149                          mft_record_size);
 150         if (buf == NULL)
 151                 goto found;
 152
 153         mftr = (struct master_file_table_record*) buf;
 154
 155         dbg("mftr->magic '%c%c%c%c'", mftr->magic[0], mftr->magic[1], mftr->magic[2], mftr->magic[3]);
 156         if (strncmp(mftr->magic, "FILE", 4) != 0)
 157                 goto found;
 158
 159         attr_off = le16_to_cpu(mftr->attrs_offset);
 160         dbg("file $Volume's attributes are at offset %i", attr_off);
 161
 162         while (1) {
 163                 attr = (struct file_attribute*) &buf[attr_off];
 164                 attr_type = le32_to_cpu(attr->type);
 165                 attr_len = le16_to_cpu(attr->len);
 166                 val_off = le16_to_cpu(attr->value_offset);
 167                 val_len = le32_to_cpu(attr->value_len);
 168                 attr_off += attr_len;
 169
 170                 if (attr_len == 0)
 171                         break;
 172
 173                 if (attr_off >= mft_record_size)
 174                         break;
 175
 176                 if (attr_type == MFT_RECORD_ATTR_END)
 177                         break;
 178
 179                 dbg("found attribute type 0x%x, len %i, at offset %i",
 180                     attr_type, attr_len, attr_off);
 181
 182                 if (attr_type == MFT_RECORD_ATTR_VOLUME_INFO) {
 183                         dbg("found info, len %i", val_len);
 184                         info = (struct volume_info*) (((__u8 *) attr) + val_off);
 185                         snprintf(id->type_version, VOLUME_ID_FORMAT_SIZE-1,
 186                                  "%u.%u", info->major_ver, info->minor_ver);
 187                 }
 188
 189                 if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
 190                         dbg("found label, len %i", val_len);
 191                         if (val_len > VOLUME_ID_LABEL_SIZE)
 192                                 val_len = VOLUME_ID_LABEL_SIZE;
 193
 194                         val = ((__u8 *) attr) + val_off;
 195                         volume_id_set_label_raw(id, val, val_len);
 196                         volume_id_set_label_unicode16(id, val, LE, val_len);
 197                 }
 198         }
 199
 200 found:
 201         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 202         id->type = "ntfs";
 203
 204         return 0;
 205 }