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Sourcecode: udev version File versions

ntfs.c

/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation; either
 *    version 2.1 of the License, or (at your option) any later version.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *    Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public
 *    License along with this library; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <asm/types.h>

#include "volume_id.h"
#include "logging.h"
#include "util.h"
#include "ntfs.h"

struct ntfs_super_block {
      __u8  jump[3];
      __u8  oem_id[8];
      __u16 bytes_per_sector;
      __u8  sectors_per_cluster;
      __u16 reserved_sectors;
      __u8  fats;
      __u16 root_entries;
      __u16 sectors;
      __u8  media_type;
      __u16 sectors_per_fat;
      __u16 sectors_per_track;
      __u16 heads;
      __u32 hidden_sectors;
      __u32 large_sectors;
      __u16 unused[2];
      __u64 number_of_sectors;
      __u64 mft_cluster_location;
      __u64 mft_mirror_cluster_location;
      __s8  cluster_per_mft_record;
      __u8  reserved1[3];
      __s8  cluster_per_index_record;
      __u8  reserved2[3];
      __u8  volume_serial[8];
      __u16 checksum;
} __attribute__((__packed__)) *ns;

struct master_file_table_record {
      __u8  magic[4];
      __u16 usa_ofs;
      __u16 usa_count;
      __u64 lsn;
      __u16 sequence_number;
      __u16 link_count;
      __u16 attrs_offset;
      __u16 flags;
      __u32 bytes_in_use;
      __u32 bytes_allocated;
} __attribute__((__packed__)) *mftr;

struct file_attribute {
      __u32 type;
      __u32 len;
      __u8  non_resident;
      __u8  name_len;
      __u16 name_offset;
      __u16 flags;
      __u16 instance;
      __u32 value_len;
      __u16 value_offset;
} __attribute__((__packed__)) *attr;

struct volume_info {
      __u64 reserved;
      __u8 major_ver;
      __u8 minor_ver;
} __attribute__((__packed__)) *info;

#define MFT_RECORD_VOLUME                 3
#define MFT_RECORD_ATTR_VOLUME_NAME       0x60
#define MFT_RECORD_ATTR_VOLUME_INFO       0x70
#define MFT_RECORD_ATTR_OBJECT_ID         0x40
#define MFT_RECORD_ATTR_END               0xffffffffu

int volume_id_probe_ntfs(struct volume_id *id, __u64 off)
{
      unsigned int sector_size;
      unsigned int cluster_size;
      __u64 mft_cluster;
      __u64 mft_off;
      unsigned int mft_record_size;
      unsigned int attr_type;
      unsigned int attr_off;
      unsigned int attr_len;
      unsigned int val_off;
      unsigned int val_len;
      const __u8 *buf;
      const __u8 *val;

      dbg("probing at offset 0x%llx", (unsigned long long) off);

      ns = (struct ntfs_super_block *) volume_id_get_buffer(id, off, 0x200);
      if (ns == NULL)
            return -1;

      if (memcmp(ns->oem_id, "NTFS", 4) != 0)
            return -1;

      volume_id_set_uuid(id, ns->volume_serial, UUID_NTFS);

      sector_size = le16_to_cpu(ns->bytes_per_sector);
      cluster_size = ns->sectors_per_cluster * sector_size;
      mft_cluster = le64_to_cpu(ns->mft_cluster_location);
      mft_off = mft_cluster * cluster_size;

      if (ns->cluster_per_mft_record < 0)
            /* size = -log2(mft_record_size); normally 1024 Bytes */
            mft_record_size = 1 << -ns->cluster_per_mft_record;
      else
            mft_record_size = ns->cluster_per_mft_record * cluster_size;

      dbg("sectorsize  0x%x", sector_size);
      dbg("clustersize 0x%x", cluster_size);
      dbg("mftcluster  %llu", (unsigned long long) mft_cluster);
      dbg("mftoffset  0x%llx", (unsigned long long) mft_off);
      dbg("cluster per mft_record  %i", ns->cluster_per_mft_record);
      dbg("mft record size  %i", mft_record_size);

      buf = volume_id_get_buffer(id, off + mft_off + (MFT_RECORD_VOLUME * mft_record_size),
                   mft_record_size);
      if (buf == NULL)
            goto found;

      mftr = (struct master_file_table_record*) buf;

      dbg("mftr->magic '%c%c%c%c'", mftr->magic[0], mftr->magic[1], mftr->magic[2], mftr->magic[3]);
      if (memcmp(mftr->magic, "FILE", 4) != 0)
            goto found;

      attr_off = le16_to_cpu(mftr->attrs_offset);
      dbg("file $Volume's attributes are at offset %i", attr_off);

      while (1) {
            attr = (struct file_attribute*) &buf[attr_off];
            attr_type = le32_to_cpu(attr->type);
            attr_len = le16_to_cpu(attr->len);
            val_off = le16_to_cpu(attr->value_offset);
            val_len = le32_to_cpu(attr->value_len);
            attr_off += attr_len;

            if (attr_len == 0)
                  break;

            if (attr_off >= mft_record_size)
                  break;

            if (attr_type == MFT_RECORD_ATTR_END)
                  break;

            dbg("found attribute type 0x%x, len %i, at offset %i",
                attr_type, attr_len, attr_off);

            if (attr_type == MFT_RECORD_ATTR_VOLUME_INFO) {
                  dbg("found info, len %i", val_len);
                  info = (struct volume_info*) (((__u8 *) attr) + val_off);
                  snprintf(id->type_version, sizeof(id->type_version)-1,
                         "%u.%u", info->major_ver, info->minor_ver);
            }

            if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
                  dbg("found label, len %i", val_len);
                  if (val_len > VOLUME_ID_LABEL_SIZE)
                        val_len = VOLUME_ID_LABEL_SIZE;

                  val = ((__u8 *) attr) + val_off;
                  volume_id_set_label_raw(id, val, val_len);
                  volume_id_set_label_unicode16(id, val, LE, val_len);
            }
      }

found:
      volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
      id->type = "ntfs";

      return 0;
}

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