extras/volume_id/volume_id/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
  36 #include "volume_id.h"
  37 #include "logging.h"
  38 #include "util.h"
  39 #include "ntfs.h"
  40
  41 struct ntfs_super_block {
  42         uint8_t         jump[3];
  43         uint8_t         oem_id[8];
  44         uint16_t        bytes_per_sector;
  45         uint8_t         sectors_per_cluster;
  46         uint16_t        reserved_sectors;
  47         uint8_t         fats;
  48         uint16_t        root_entries;
  49         uint16_t        sectors;
  50         uint8_t         media_type;
  51         uint16_t        sectors_per_fat;
  52         uint16_t        sectors_per_track;
  53         uint16_t        heads;
  54         uint32_t        hidden_sectors;
  55         uint32_t        large_sectors;
  56         uint16_t        unused[2];
  57         uint64_t        number_of_sectors;
  58         uint64_t        mft_cluster_location;
  59         uint64_t        mft_mirror_cluster_location;
  60         int8_t          cluster_per_mft_record;
  61         uint8_t         reserved1[3];
  62         int8_t          cluster_per_index_record;
  63         uint8_t         reserved2[3];
  64         uint8_t         volume_serial[8];
  65         uint16_t        checksum;
  66 } __attribute__((__packed__)) *ns;
  67
  68 struct master_file_table_record {
  69         uint8_t         magic[4];
  70         uint16_t        usa_ofs;
  71         uint16_t        usa_count;
  72         uint64_t        lsn;
  73         uint16_t        sequence_number;
  74         uint16_t        link_count;
  75         uint16_t        attrs_offset;
  76         uint16_t        flags;
  77         uint32_t        bytes_in_use;
  78         uint32_t        bytes_allocated;
  79 } __attribute__((__packed__)) *mftr;
  80
  81 struct file_attribute {
  82         uint32_t        type;
  83         uint32_t        len;
  84         uint8_t         non_resident;
  85         uint8_t         name_len;
  86         uint16_t        name_offset;
  87         uint16_t        flags;
  88         uint16_t        instance;
  89         uint32_t        value_len;
  90         uint16_t        value_offset;
  91 } __attribute__((__packed__)) *attr;
  92
  93 struct volume_info {
  94         uint64_t        reserved;
  95         uint8_t         major_ver;
  96         uint8_t         minor_ver;
  97 } __attribute__((__packed__)) *info;
  98
  99 #define MFT_RECORD_VOLUME                       3
 100 #define MFT_RECORD_ATTR_VOLUME_NAME             0x60
 101 #define MFT_RECORD_ATTR_VOLUME_INFO             0x70
 102 #define MFT_RECORD_ATTR_OBJECT_ID               0x40
 103 #define MFT_RECORD_ATTR_END                     0xffffffffu
 104
 105 int volume_id_probe_ntfs(struct volume_id *id, uint64_t off)
 106 {
 107         unsigned int sector_size;
 108         unsigned int cluster_size;
 109         uint64_t mft_cluster;
 110         uint64_t mft_off;
 111         unsigned int mft_record_size;
 112         unsigned int attr_type;
 113         unsigned int attr_off;
 114         unsigned int attr_len;
 115         unsigned int val_off;
 116         unsigned int val_len;
 117         const uint8_t *buf;
 118         const uint8_t *val;
 119
 120         dbg("probing at offset 0x%llx", (unsigned long long) off);
 121
 122         ns = (struct ntfs_super_block *) volume_id_get_buffer(id, off, 0x200);
 123         if (ns == NULL)
 124                 return -1;
 125
 126         if (memcmp(ns->oem_id, "NTFS", 4) != 0)
 127                 return -1;
 128
 129         volume_id_set_uuid(id, ns->volume_serial, UUID_NTFS);
 130
 131         sector_size = le16_to_cpu(ns->bytes_per_sector);
 132         cluster_size = ns->sectors_per_cluster * sector_size;
 133         mft_cluster = le64_to_cpu(ns->mft_cluster_location);
 134         mft_off = mft_cluster * cluster_size;
 135
 136         if (ns->cluster_per_mft_record < 0)
 137                 /* size = -log2(mft_record_size); normally 1024 Bytes */
 138                 mft_record_size = 1 << -ns->cluster_per_mft_record;
 139         else
 140                 mft_record_size = ns->cluster_per_mft_record * cluster_size;
 141
 142         dbg("sectorsize  0x%x", sector_size);
 143         dbg("clustersize 0x%x", cluster_size);
 144         dbg("mftcluster  %llu", (unsigned long long) mft_cluster);
 145         dbg("mftoffset  0x%llx", (unsigned long long) mft_off);
 146         dbg("cluster per mft_record  %i", ns->cluster_per_mft_record);
 147         dbg("mft record size  %i", mft_record_size);
 148
 149         buf = volume_id_get_buffer(id, off + mft_off + (MFT_RECORD_VOLUME * mft_record_size),
 150                          mft_record_size);
 151         if (buf == NULL)
 152                 goto found;
 153
 154         mftr = (struct master_file_table_record*) buf;
 155
 156         dbg("mftr->magic '%c%c%c%c'", mftr->magic[0], mftr->magic[1], mftr->magic[2], mftr->magic[3]);
 157         if (memcmp(mftr->magic, "FILE", 4) != 0)
 158                 goto found;
 159
 160         attr_off = le16_to_cpu(mftr->attrs_offset);
 161         dbg("file $Volume's attributes are at offset %i", attr_off);
 162
 163         while (1) {
 164                 attr = (struct file_attribute*) &buf[attr_off];
 165                 attr_type = le32_to_cpu(attr->type);
 166                 attr_len = le16_to_cpu(attr->len);
 167                 val_off = le16_to_cpu(attr->value_offset);
 168                 val_len = le32_to_cpu(attr->value_len);
 169                 attr_off += attr_len;
 170
 171                 if (attr_len == 0)
 172                         break;
 173
 174                 if (attr_off >= mft_record_size)
 175                         break;
 176
 177                 if (attr_type == MFT_RECORD_ATTR_END)
 178                         break;
 179
 180                 dbg("found attribute type 0x%x, len %i, at offset %i",
 181                     attr_type, attr_len, attr_off);
 182
 183                 if (attr_type == MFT_RECORD_ATTR_VOLUME_INFO) {
 184                         dbg("found info, len %i", val_len);
 185                         info = (struct volume_info*) (((uint8_t *) attr) + val_off);
 186                         snprintf(id->type_version, sizeof(id->type_version)-1,
 187                                  "%u.%u", info->major_ver, info->minor_ver);
 188                 }
 189
 190                 if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
 191                         dbg("found label, len %i", val_len);
 192                         if (val_len > VOLUME_ID_LABEL_SIZE)
 193                                 val_len = VOLUME_ID_LABEL_SIZE;
 194
 195                         val = ((uint8_t *) attr) + val_off;
 196                         volume_id_set_label_raw(id, val, val_len);
 197                         volume_id_set_label_unicode16(id, val, LE, val_len);
 198                 }
 199         }
 200
 201 found:
 202         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 203         id->type = "ntfs";
 204
 205         return 0;
 206 }