107 lines
3.9 KiB
C
107 lines
3.9 KiB
C
/*
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* $Id$
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*
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* mft.h - Exports for MFT record handling. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2000-2002 Anton Altaparmakov.
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program/include file is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (in the main directory of the Linux-NTFS
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* distribution in the file COPYING); if not, write to the Free Software
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* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _NTFS_MFT_H
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#define _NTFS_MFT_H
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#include "volume.h"
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#include "layout.h"
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extern int ntfs_read_mft_records(const ntfs_volume *vol, const MFT_REF mref,
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const s64 count, MFT_RECORD *b);
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/**
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* ntfs_read_mft_record - read a record from the mft
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* @vol: volume to read from
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* @mref: mft record number to read
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* @b: output data buffer
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*
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* Read the mft record specified by @mref from volume @vol into buffer @b.
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* Return 0 on success or -1 on error, with errno set to the error code.
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*
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* The read mft record is mst deprotected and is hence ready to use. The caller
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* should check the record with is_baad_record() in case mst deprotection
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* failed.
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*
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* NOTE: @b has to be at least of size vol->mft_record_size.
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*/
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static __inline__ int ntfs_read_mft_record(const ntfs_volume *vol,
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const MFT_REF mref, MFT_RECORD *b)
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{
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return ntfs_read_mft_records(vol, mref, 1, b);
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}
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extern int ntfs_read_file_record(const ntfs_volume *vol, const MFT_REF mref,
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MFT_RECORD **mrec, ATTR_RECORD **attr);
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extern int ntfs_write_mft_records(const ntfs_volume *vol, const MFT_REF mref,
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const s64 count, MFT_RECORD *b);
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/**
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* ntfs_write_mft_record - write an mft record to disk
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* @vol: volume to write to
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* @mref: mft record number to write
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* @b: data buffer containing the mft record to write
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*
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* Write the mft record specified by @mref from buffer @b to volume @vol.
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* Return 0 on success or -1 on error, with errno set to the error code.
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*
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* Before the mft record is written, it is mst protected. After the write, it
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* is deprotected again, thus resulting in an increase in the update sequence
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* number inside the buffer @b.
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*
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* NOTE: @b has to be at least of size vol->mft_record_size.
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*/
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static __inline__ int ntfs_write_mft_record(const ntfs_volume *vol,
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const MFT_REF mref, MFT_RECORD *b)
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{
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return ntfs_write_mft_records(vol, mref, 1, b);
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}
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/**
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* ntfs_get_mft_record_data_size - return number of bytes used in mft record @b
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* @m: mft record to get the data size of
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*
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* Takes the mft record @m and returns the number of bytes used in the record
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* or 0 on error (i.e. @m is not a valid mft record). Zero is not a valid size
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* for an mft record as it at least has to have the MFT_RECORD, thus making the
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* minimum size:
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* (sizeof(MFT_RECORD) + 7) & ~7 + sizeof(ATTR_TYPES) = 52 bytes
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* Aside: The 8-byte alignment and the 4 bytes for the attribute type are needed
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* as each mft record has to have a list of attributes even if it only contains
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* the attribute $END which doesn't contain anything else apart from its type.
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* Also, you would expect every mft record to contain an update sequence array
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* as well but that could in theory be non-existent (don't know if Windows'
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* NTFS driver/chkdsk wouldn't view this as corruption in itself though).
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*/
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static __inline__ u32 ntfs_get_mft_record_data_size(const MFT_RECORD *m)
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{
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if (!m || !is_mft_record(m->magic))
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return 0;
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/* Get the number of used bytes and return it. */
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return le32_to_cpu(m->bytes_in_use);
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}
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#endif /* defined _NTFS_MFT_H */
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