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usbloadergx/source/libntfs/bootsect.c
giantpune 9e79c9d99b * remove little unused code 
* code cleanup
2010-09-18 23:16:05 +00:00

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/**
* bootsect.c - Boot sector handling code. Originated from the Linux-NTFS project.
*
* Copyright (c) 2000-2006 Anton Altaparmakov
* Copyright (c) 2003-2008 Szabolcs Szakacsits
* Copyright (c) 2005 Yura Pakhuchiy
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the NTFS-3G
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include "compat.h"
#include "bootsect.h"
#include "debug.h"
#include "logging.h"
/**
* ntfs_boot_sector_is_ntfs - check if buffer contains a valid ntfs boot sector
* @b: buffer containing putative boot sector to analyze
* @silent: if zero, output progress messages to stderr
*
* Check if the buffer @b contains a valid ntfs boot sector. The buffer @b
* must be at least 512 bytes in size.
*
* If @silent is zero, output progress messages to stderr. Otherwise, do not
* output any messages (except when configured with --enable-debug in which
* case warning/debug messages may be displayed).
*
* Return TRUE if @b contains a valid ntfs boot sector and FALSE if not.
*/
BOOL ntfs_boot_sector_is_ntfs( NTFS_BOOT_SECTOR *b )
{
u32 i;
BOOL ret = FALSE;
ntfs_log_debug( "Beginning bootsector check.\n" );
ntfs_log_debug( "Checking OEMid, NTFS signature.\n" );
if ( b->oem_id != cpu_to_le64( 0x202020205346544eULL ) ) /* "NTFS " */
{
ntfs_log_error( "NTFS signature is missing.\n" );
goto not_ntfs;
}
ntfs_log_debug( "Checking bytes per sector.\n" );
if ( le16_to_cpu( b->bpb.bytes_per_sector ) < 256 ||
le16_to_cpu( b->bpb.bytes_per_sector ) > 4096 )
{
ntfs_log_error( "Unexpected bytes per sector value (%d).\n",
le16_to_cpu( b->bpb.bytes_per_sector ) );
goto not_ntfs;
}
ntfs_log_debug( "Checking sectors per cluster.\n" );
switch ( b->bpb.sectors_per_cluster )
{
case 1: case 2: case 4: case 8: case 16: case 32: case 64: case 128:
break;
default:
ntfs_log_error( "Unexpected sectors per cluster value (%d).\n",
b->bpb.sectors_per_cluster );
goto not_ntfs;
}
ntfs_log_debug( "Checking cluster size.\n" );
i = ( u32 )le16_to_cpu( b->bpb.bytes_per_sector ) *
b->bpb.sectors_per_cluster;
if ( i > 65536 )
{
ntfs_log_error( "Unexpected cluster size (%d).\n", i );
goto not_ntfs;
}
ntfs_log_debug( "Checking reserved fields are zero.\n" );
if ( le16_to_cpu( b->bpb.reserved_sectors ) ||
le16_to_cpu( b->bpb.root_entries ) ||
le16_to_cpu( b->bpb.sectors ) ||
le16_to_cpu( b->bpb.sectors_per_fat ) ||
le32_to_cpu( b->bpb.large_sectors ) ||
b->bpb.fats )
{
ntfs_log_error( "Reserved fields aren't zero "
"(%d, %d, %d, %d, %d, %d).\n",
le16_to_cpu( b->bpb.reserved_sectors ),
le16_to_cpu( b->bpb.root_entries ),
le16_to_cpu( b->bpb.sectors ),
le16_to_cpu( b->bpb.sectors_per_fat ),
le32_to_cpu( b->bpb.large_sectors ),
b->bpb.fats );
goto not_ntfs;
}
ntfs_log_debug( "Checking clusters per mft record.\n" );
if ( ( u8 )b->clusters_per_mft_record < 0xe1 ||
( u8 )b->clusters_per_mft_record > 0xf7 )
{
switch ( b->clusters_per_mft_record )
{
case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40:
break;
default:
ntfs_log_error( "Unexpected clusters per mft record "
"(%d).\n", b->clusters_per_mft_record );
goto not_ntfs;
}
}
ntfs_log_debug( "Checking clusters per index block.\n" );
if ( ( u8 )b->clusters_per_index_record < 0xe1 ||
( u8 )b->clusters_per_index_record > 0xf7 )
{
switch ( b->clusters_per_index_record )
{
case 1: case 2: case 4: case 8: case 0x10: case 0x20: case 0x40:
break;
default:
ntfs_log_error( "Unexpected clusters per index record "
"(%d).\n", b->clusters_per_index_record );
goto not_ntfs;
}
}
if ( b->end_of_sector_marker != cpu_to_le16( 0xaa55 ) )
ntfs_log_debug( "Warning: Bootsector has invalid end of sector "
"marker.\n" );
ntfs_log_debug( "Bootsector check completed successfully.\n" );
ret = TRUE;
not_ntfs:
return ret;
}
static const char *last_sector_error =
"HINTS: Either the volume is a RAID/LDM but it wasn't setup yet,\n"
" or it was not setup correctly (e.g. by not using mdadm --build ...),\n"
" or a wrong device is tried to be mounted,\n"
" or the partition table is corrupt (partition is smaller than NTFS),\n"
" or the NTFS boot sector is corrupt (NTFS size is not valid).\n";
/**
* ntfs_boot_sector_parse - setup an ntfs volume from an ntfs boot sector
* @vol: ntfs_volume to setup
* @bs: buffer containing ntfs boot sector to parse
*
* Parse the ntfs bootsector @bs and setup the ntfs volume @vol with the
* obtained values.
*
* Return 0 on success or -1 on error with errno set to the error code EINVAL.
*/
int ntfs_boot_sector_parse( ntfs_volume *vol, const NTFS_BOOT_SECTOR *bs )
{
s64 sectors;
u8 sectors_per_cluster;
s8 c;
/* We return -1 with errno = EINVAL on error. */
errno = EINVAL;
vol->sector_size = le16_to_cpu( bs->bpb.bytes_per_sector );
vol->sector_size_bits = ffs( vol->sector_size ) - 1;
ntfs_log_debug( "SectorSize = 0x%x\n", vol->sector_size );
ntfs_log_debug( "SectorSizeBits = %u\n", vol->sector_size_bits );
/*
* The bounds checks on mft_lcn and mft_mirr_lcn (i.e. them being
* below or equal the number_of_clusters) really belong in the
* ntfs_boot_sector_is_ntfs but in this way we can just do this once.
*/
sectors_per_cluster = bs->bpb.sectors_per_cluster;
ntfs_log_debug( "SectorsPerCluster = 0x%x\n", sectors_per_cluster );
if ( sectors_per_cluster & ( sectors_per_cluster - 1 ) )
{
ntfs_log_error( "sectors_per_cluster (%d) is not a power of 2."
"\n", sectors_per_cluster );
return -1;
}
sectors = sle64_to_cpu( bs->number_of_sectors );
ntfs_log_debug( "NumberOfSectors = %lld\n", ( long long )sectors );
if ( !sectors )
{
ntfs_log_error( "Volume size is set to zero.\n" );
return -1;
}
if ( vol->dev->d_ops->seek( vol->dev,
( sectors - 1 ) << vol->sector_size_bits,
SEEK_SET ) == -1 )
{
ntfs_log_perror( "Failed to read last sector (%lld)",
( long long )sectors );
ntfs_log_error( "%s", last_sector_error );
return -1;
}
vol->nr_clusters = sectors >> ( ffs( sectors_per_cluster ) - 1 );
vol->mft_lcn = sle64_to_cpu( bs->mft_lcn );
vol->mftmirr_lcn = sle64_to_cpu( bs->mftmirr_lcn );
ntfs_log_debug( "MFT LCN = %lld\n", ( long long )vol->mft_lcn );
ntfs_log_debug( "MFTMirr LCN = %lld\n", ( long long )vol->mftmirr_lcn );
if ( vol->mft_lcn > vol->nr_clusters ||
vol->mftmirr_lcn > vol->nr_clusters )
{
ntfs_log_error( "$MFT LCN (%lld) or $MFTMirr LCN (%lld) is "
"greater than the number of clusters (%lld).\n",
( long long )vol->mft_lcn, ( long long )vol->mftmirr_lcn,
( long long )vol->nr_clusters );
return -1;
}
vol->cluster_size = sectors_per_cluster * vol->sector_size;
if ( vol->cluster_size & ( vol->cluster_size - 1 ) )
{
ntfs_log_error( "cluster_size (%d) is not a power of 2.\n",
vol->cluster_size );
return -1;
}
vol->cluster_size_bits = ffs( vol->cluster_size ) - 1;
/*
* Need to get the clusters per mft record and handle it if it is
* negative. Then calculate the mft_record_size. A value of 0x80 is
* illegal, thus signed char is actually ok!
*/
c = bs->clusters_per_mft_record;
ntfs_log_debug( "ClusterSize = 0x%x\n", ( unsigned )vol->cluster_size );
ntfs_log_debug( "ClusterSizeBits = %u\n", vol->cluster_size_bits );
ntfs_log_debug( "ClustersPerMftRecord = 0x%x\n", c );
/*
* When clusters_per_mft_record is negative, it means that it is to
* be taken to be the negative base 2 logarithm of the mft_record_size
* min bytes. Then:
* mft_record_size = 2^(-clusters_per_mft_record) bytes.
*/
if ( c < 0 )
vol->mft_record_size = 1 << -c;
else
vol->mft_record_size = c << vol->cluster_size_bits;
if ( vol->mft_record_size & ( vol->mft_record_size - 1 ) )
{
ntfs_log_error( "mft_record_size (%d) is not a power of 2.\n",
vol->mft_record_size );
return -1;
}
vol->mft_record_size_bits = ffs( vol->mft_record_size ) - 1;
ntfs_log_debug( "MftRecordSize = 0x%x\n", ( unsigned )vol->mft_record_size );
ntfs_log_debug( "MftRecordSizeBits = %u\n", vol->mft_record_size_bits );
/* Same as above for INDX record. */
c = bs->clusters_per_index_record;
ntfs_log_debug( "ClustersPerINDXRecord = 0x%x\n", c );
if ( c < 0 )
vol->indx_record_size = 1 << -c;
else
vol->indx_record_size = c << vol->cluster_size_bits;
vol->indx_record_size_bits = ffs( vol->indx_record_size ) - 1;
ntfs_log_debug( "INDXRecordSize = 0x%x\n", ( unsigned )vol->indx_record_size );
ntfs_log_debug( "INDXRecordSizeBits = %u\n", vol->indx_record_size_bits );
/*
* Work out the size of the MFT mirror in number of mft records. If the
* cluster size is less than or equal to the size taken by four mft
* records, the mft mirror stores the first four mft records. If the
* cluster size is bigger than the size taken by four mft records, the
* mft mirror contains as many mft records as will fit into one
* cluster.
*/
if ( vol->cluster_size <= 4 * vol->mft_record_size )
vol->mftmirr_size = 4;
else
vol->mftmirr_size = vol->cluster_size / vol->mft_record_size;
return 0;
}
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