volume.c

添加linux下对NTFS格式文件系统访问支持的源代码ntfs-3g

/**
 * volume.c - NTFS volume handling code. Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2000-2006 Anton Altaparmakov
 * Copyright (c) 2002-2006 Szabolcs Szakacsits
 * Copyright (c) 2004-2005 Richard Russon
 *
 * 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_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#include "volume.h"
#include "attrib.h"
#include "mft.h"
#include "bootsect.h"
#include "device.h"
#include "debug.h"
#include "inode.h"
#include "runlist.h"
#include "logfile.h"
#include "dir.h"
#include "logging.h"
#include "misc.h"

#ifndef PATH_MAX
#define PATH_MAX 4096
#endif

/**
 * ntfs_volume_alloc - Create an NTFS volume object and initialise it
 *
 * Description...
 *
 * Returns:
 */
ntfs_volume *ntfs_volume_alloc(void)
{
	return calloc(1, sizeof(ntfs_volume));
}

/**
 * __ntfs_volume_release - Destroy an NTFS volume object
 * @v:
 *
 * Description...
 *
 * Returns:
 */
static void __ntfs_volume_release(ntfs_volume *v)
{
	if (v->lcnbmp_ni && NInoDirty(v->lcnbmp_ni))
		ntfs_inode_sync(v->lcnbmp_ni);
	if (v->vol_ni)
		ntfs_inode_close(v->vol_ni);
	if (v->lcnbmp_na)
		ntfs_attr_close(v->lcnbmp_na);
	if (v->lcnbmp_ni)
		ntfs_inode_close(v->lcnbmp_ni);
	if (v->mft_ni && NInoDirty(v->mft_ni))
		ntfs_inode_sync(v->mft_ni);
	if (v->mftbmp_na)
		ntfs_attr_close(v->mftbmp_na);
	if (v->mft_na)
		ntfs_attr_close(v->mft_na);
	if (v->mft_ni)
		ntfs_inode_close(v->mft_ni);
	if (v->mftmirr_ni && NInoDirty(v->mftmirr_ni))
		ntfs_inode_sync(v->mftmirr_ni);
	if (v->mftmirr_na)
		ntfs_attr_close(v->mftmirr_na);
	if (v->mftmirr_ni)
		ntfs_inode_close(v->mftmirr_ni);
	if (v->dev) {
		struct ntfs_device *dev = v->dev;

		dev->d_ops->sync(dev);
		if (dev->d_ops->close(dev))
			ntfs_log_perror("Failed to close the device");
	}
	free(v->vol_name);
	free(v->upcase);
	free(v->attrdef);
	free(v);
}

static void ntfs_attr_setup_flag(ntfs_inode *ni)
{
	STANDARD_INFORMATION *si;

	si = ntfs_attr_readall(ni, AT_STANDARD_INFORMATION, AT_UNNAMED, 0, NULL);
	if (si) {
		ni->flags = si->file_attributes;
		free(si);
	}
}

/**
 * ntfs_mft_load - load the $MFT and setup the ntfs volume with it
 * @vol:	ntfs volume whose $MFT to load
 *
 * Load $MFT from @vol and setup @vol with it. After calling this function the
 * volume @vol is ready for use by all read access functions provided by the
 * ntfs library.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_load(ntfs_volume *vol)
{
	VCN next_vcn, last_vcn, highest_vcn;
	s64 l;
	MFT_RECORD *mb = NULL;
	ntfs_attr_search_ctx *ctx = NULL;
	ATTR_RECORD *a;
	int eo;

	/* Manually setup an ntfs_inode. */
	vol->mft_ni = ntfs_inode_allocate(vol);
	mb = ntfs_malloc(vol->mft_record_size);
	if (!vol->mft_ni || !mb) {
		ntfs_log_perror("Error allocating memory for $MFT");
		goto error_exit;
	}
	vol->mft_ni->mft_no = 0;
	vol->mft_ni->mrec = mb;
	/* Can't use any of the higher level functions yet! */
	l = ntfs_mst_pread(vol->dev, vol->mft_lcn << vol->cluster_size_bits, 1,
			vol->mft_record_size, mb);
	if (l != 1) {
		if (l != -1)
			errno = EIO;
		ntfs_log_perror("Error reading $MFT");
		goto error_exit;
	}
	if (ntfs_is_baad_record(mb->magic)) {
		ntfs_log_error("Incomplete multi sector transfer detected in "
				"$MFT.\n");
		goto io_error_exit;
	}
	if (!ntfs_is_mft_record(mb->magic)) {
		ntfs_log_error("$MFT has invalid magic.\n");
		goto io_error_exit;
	}
	ctx = ntfs_attr_get_search_ctx(vol->mft_ni, NULL);
	if (!ctx) {
		ntfs_log_perror("Failed to allocate attribute search context");
		goto error_exit;
	}
	if (p2n(ctx->attr) < p2n(mb) ||
			(char*)ctx->attr > (char*)mb + vol->mft_record_size) {
		ntfs_log_error("$MFT is corrupt.\n");
		goto io_error_exit;
	}
	/* Find the $ATTRIBUTE_LIST attribute in $MFT if present. */
	if (ntfs_attr_lookup(AT_ATTRIBUTE_LIST, AT_UNNAMED, 0, 0, 0, NULL, 0,
			ctx)) {
		if (errno != ENOENT) {
			ntfs_log_error("$MFT has corrupt attribute list.\n");
			goto io_error_exit;
		}
		goto mft_has_no_attr_list;
	}
	NInoSetAttrList(vol->mft_ni);
	l = ntfs_get_attribute_value_length(ctx->attr);
	if (l <= 0 || l > 0x40000) {
		ntfs_log_error("$MFT/$ATTR_LIST invalid length (%lld).\n",
			       (long long)l);
		goto io_error_exit;
	}
	vol->mft_ni->attr_list_size = l;
	vol->mft_ni->attr_list = ntfs_malloc(l);
	if (!vol->mft_ni->attr_list)
		goto error_exit;
	
	l = ntfs_get_attribute_value(vol, ctx->attr, vol->mft_ni->attr_list);
	if (!l) {
		ntfs_log_error("Failed to get value of $MFT/$ATTR_LIST.\n");
		goto io_error_exit;
	}
	if (l != vol->mft_ni->attr_list_size) {
		ntfs_log_error("Partial read of $MFT/$ATTR_LIST (%lld != "
			       "%u).\n", (long long)l,
			       vol->mft_ni->attr_list_size);
		goto io_error_exit;
	}

mft_has_no_attr_list:

	ntfs_attr_setup_flag(vol->mft_ni);
	
	/* We now have a fully setup ntfs inode for $MFT in vol->mft_ni. */
	
	/* Get an ntfs attribute for $MFT/$DATA and set it up, too. */
	vol->mft_na = ntfs_attr_open(vol->mft_ni, AT_DATA, AT_UNNAMED, 0);
	if (!vol->mft_na) {
		ntfs_log_perror("Failed to open ntfs attribute");
		goto error_exit;
	}
	/* Read all extents from the $DATA attribute in $MFT. */
	ntfs_attr_reinit_search_ctx(ctx);
	last_vcn = vol->mft_na->allocated_size >> vol->cluster_size_bits;
	highest_vcn = next_vcn = 0;
	a = NULL;
	while (!ntfs_attr_lookup(AT_DATA, AT_UNNAMED, 0, 0, next_vcn, NULL, 0,
			ctx)) {
		runlist_element *nrl;

		a = ctx->attr;
		/* $MFT must be non-resident. */
		if (!a->non_resident) {
			ntfs_log_error("$MFT must be non-resident.\n");
			goto io_error_exit;
		}
		/* $MFT must be uncompressed and unencrypted. */
		if (a->flags & ATTR_COMPRESSION_MASK ||
				a->flags & ATTR_IS_ENCRYPTED) {
			ntfs_log_error("$MFT must be uncompressed and "
				       "unencrypted.\n");
			goto io_error_exit;
		}
		/*
		 * Decompress the mapping pairs array of this extent and merge
		 * the result into the existing runlist. No need for locking
		 * as we have exclusive access to the inode at this time and we
		 * are a mount in progress task, too.
		 */
		nrl = ntfs_mapping_pairs_decompress(vol, a, vol->mft_na->rl);
		if (!nrl) {
			ntfs_log_perror("ntfs_mapping_pairs_decompress() failed");
			goto error_exit;
		}
		vol->mft_na->rl = nrl;

		/* Get the lowest vcn for the next extent. */
		highest_vcn = sle64_to_cpu(a->highest_vcn);
		next_vcn = highest_vcn + 1;

		/* Only one extent or error, which we catch below. */
		if (next_vcn <= 0)
			break;

		/* Avoid endless loops due to corruption. */
		if (next_vcn < sle64_to_cpu(a->lowest_vcn)) {
			ntfs_log_error("$MFT has corrupt attribute list.\n");
			goto io_error_exit;
		}
	}
	if (!a) {
		ntfs_log_error("$MFT/$DATA attribute not found.\n");
		goto io_error_exit;
	}
	if (highest_vcn && highest_vcn != last_vcn - 1) {
		ntfs_log_error("Failed to load runlist for $MFT/$DATA.\n");
		ntfs_log_error("highest_vcn = 0x%llx, last_vcn - 1 = 0x%llx\n",
			       (long long)highest_vcn, (long long)last_vcn - 1);
		goto io_error_exit;
	}
	/* Done with the $Mft mft record. */
	ntfs_attr_put_search_ctx(ctx);
	ctx = NULL;
	/*
	 * The volume is now setup so we can use all read access functions.
	 */
	vol->mftbmp_na = ntfs_attr_open(vol->mft_ni, AT_BITMAP, AT_UNNAMED, 0);
	if (!vol->mftbmp_na) {
		ntfs_log_perror("Failed to open $MFT/$BITMAP");
		goto error_exit;
	}
	return 0;
io_error_exit:
	errno = EIO;
error_exit:
	eo = errno;
	if (ctx)
		ntfs_attr_put_search_ctx(ctx);
	if (vol->mft_na) {
		ntfs_attr_close(vol->mft_na);
		vol->mft_na = NULL;
	}
	if (vol->mft_ni) {
		ntfs_inode_close(vol->mft_ni);
		vol->mft_ni = NULL;
	}
	errno = eo;
	return -1;
}

/**
 * ntfs_mftmirr_load - load the $MFTMirr and setup the ntfs volume with it
 * @vol:	ntfs volume whose $MFTMirr to load
 *
 * Load $MFTMirr from @vol and setup @vol with it. After calling this function
 * the volume @vol is ready for use by all write access functions provided by
 * the ntfs library (assuming ntfs_mft_load() has been called successfully
 * beforehand).
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mftmirr_load(ntfs_volume *vol)
{
	int err;

	vol->mftmirr_ni = ntfs_inode_open(vol, FILE_MFTMirr);
	if (!vol->mftmirr_ni) {
		ntfs_log_perror("Failed to open inode $MFTMirr");
		return -1;
	}
	
	vol->mftmirr_na = ntfs_attr_open(vol->mftmirr_ni, AT_DATA, AT_UNNAMED, 0);
	if (!vol->mftmirr_na) {
		ntfs_log_perror("Failed to open $MFTMirr/$DATA");
		goto error_exit;
	}
	
	if (ntfs_attr_map_runlist(vol->mftmirr_na, 0) < 0) {
		ntfs_log_perror("Failed to map runlist of $MFTMirr/$DATA");
		goto error_exit;
	}
	
	return 0;

error_exit:
	err = errno;
	if (vol->mftmirr_na) {
		ntfs_attr_close(vol->mftmirr_na);
		vol->mftmirr_na = NULL;
	}
	ntfs_inode_close(vol->mftmirr_ni);
	vol->mftmirr_ni = NULL;
	errno = err;
	return -1;
}

/**
 * ntfs_volume_startup - allocate and setup an ntfs volume
 * @dev:	device to open
 * @flags:	optional mount flags
 *
 * Load, verify, and parse bootsector; load and setup $MFT and $MFTMirr. After
 * calling this function, the volume is setup sufficiently to call all read
 * and write access functions provided by the library.
 *
 * Return the allocated volume structure on success and NULL on error with
 * errno set to the error code.
 */
ntfs_volume *ntfs_volume_startup(struct ntfs_device *dev, unsigned long flags)
{
	LCN mft_zone_size, mft_lcn;
	s64 br;
	ntfs_volume *vol;
	NTFS_BOOT_SECTOR *bs;
	int eo;
#ifdef DEBUG
	const char *OK = "OK\n";
	const char *FAILED = "FAILED\n";
#endif

	if (!dev || !dev->d_ops || !dev->d_name) {
		errno = EINVAL;
		return NULL;
	}

	bs = ntfs_malloc(sizeof(NTFS_BOOT_SECTOR));
	if (!bs)
		return NULL;
	
	/* Allocate the volume structure. */
	vol = ntfs_volume_alloc();
	if (!vol)
		goto error_exit;
	/* Create the default upcase table. */
	vol->upcase_len = 65536;
	vol->upcase = ntfs_malloc(vol->upcase_len * sizeof(ntfschar));
	if (!vol->upcase)
		goto error_exit;
	
	ntfs_upcase_table_build(vol->upcase,
			vol->upcase_len * sizeof(ntfschar));
	if (flags & MS_RDONLY)
		NVolSetReadOnly(vol);
	if (flags & MS_NOATIME)
		NVolSetNoATime(vol);
	ntfs_log_debug("Reading bootsector... ");
	if (dev->d_ops->open(dev, NVolReadOnly(vol) ? O_RDONLY: O_RDWR)) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Error opening partition device");
		goto error_exit;
	}
	/* Attach the device to the volume. */
	vol->dev = dev;
	/* Now read the bootsector. */
	br = ntfs_pread(dev, 0, sizeof(NTFS_BOOT_SECTOR), bs);
	if (br != sizeof(NTFS_BOOT_SECTOR)) {
		ntfs_log_debug(FAILED);
		if (br != -1)
			errno = EINVAL;
		if (!br)
			ntfs_log_error("Partition is smaller than bootsector "
				       "size.\n");
		else
			ntfs_log_perror("Error reading bootsector");
		goto error_exit;
	}
	ntfs_log_debug(OK);
	if (!ntfs_boot_sector_is_ntfs(bs)) {
		errno = EINVAL;
		goto error_exit;
	}
	if (ntfs_boot_sector_parse(vol, bs) < 0)
		goto error_exit;
	
	free(bs);
	bs = NULL;
	/* Now set the device block size to the sector size. */
	if (ntfs_device_block_size_set(vol->dev, vol->sector_size))
		ntfs_log_debug("Failed to set the device block size to the "
				"sector size.  This may affect performance "
				"but should be harmless otherwise.  Error: "
				"%s\n", strerror(errno));
	
	/* We now initialize the cluster allocator. */

	mft_zone_size = min(vol->nr_clusters >> 3,      /* 12.5% */
			    200 * 1000 * 1024 >> vol->cluster_size_bits);

	/* Setup the mft zone. */
	vol->mft_zone_start = vol->mft_zone_pos = vol->mft_lcn;
	ntfs_log_debug("mft_zone_pos = 0x%llx\n", (long long)vol->mft_zone_pos);

	/*
	 * Calculate the mft_lcn for an unmodified NTFS volume (see mkntfs
	 * source) and if the actual mft_lcn is in the expected place or even
	 * further to the front of the volume, extend the mft_zone to cover the
	 * beginning of the volume as well. This is in order to protect the
	 * area reserved for the mft bitmap as well within the mft_zone itself.
	 * On non-standard volumes we don't protect it as the overhead would be
	 * higher than the speed increase we would get by doing it.
	 */
	mft_lcn = (8192 + 2 * vol->cluster_size - 1) / vol->cluster_size;
	if (mft_lcn * vol->cluster_size < 16 * 1024)
		mft_lcn = (16 * 1024 + vol->cluster_size - 1) /
				vol->cluster_size;
	if (vol->mft_zone_start <= mft_lcn)
		vol->mft_zone_start = 0;
	ntfs_log_debug("mft_zone_start = 0x%llx\n", (long long)vol->mft_zone_start);

	/*
	 * Need to cap the mft zone on non-standard volumes so that it does
	 * not point outside the boundaries of the volume. We do this by
	 * halving the zone size until we are inside the volume.
	 */
	vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
	while (vol->mft_zone_end >= vol->nr_clusters) {
		mft_zone_size >>= 1;
		vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
	}
	ntfs_log_debug("mft_zone_end = 0x%llx\n", (long long)vol->mft_zone_end);

	/*