volume.c

添加linux下对NTFS格式文件系统访问支持的源代码ntfs-3g

	 * Set the current position within each data zone to the start of the
	 * respective zone.
	 */
	vol->data1_zone_pos = vol->mft_zone_end;
	ntfs_log_debug("data1_zone_pos = 0x%llx\n", vol->data1_zone_pos);
	vol->data2_zone_pos = 0;
	ntfs_log_debug("data2_zone_pos = 0x%llx\n", vol->data2_zone_pos);

	/* Set the mft data allocation position to mft record 24. */
	vol->mft_data_pos = 24;

	/*
	 * The cluster allocator is now fully operational.
	 */

	/* Need to setup $MFT so we can use the library read functions. */
	ntfs_log_debug("Loading $MFT... ");
	if (ntfs_mft_load(vol) < 0) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to load $MFT");
		goto error_exit;
	}
	ntfs_log_debug(OK);

	/* Need to setup $MFTMirr so we can use the write functions, too. */
	ntfs_log_debug("Loading $MFTMirr... ");
	if (ntfs_mftmirr_load(vol) < 0) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to load $MFTMirr");
		goto error_exit;
	}
	ntfs_log_debug(OK);
	return vol;
error_exit:
	eo = errno;
	free(bs);
	if (vol)
		__ntfs_volume_release(vol);
	errno = eo;
	return NULL;
}

/**
 * ntfs_volume_check_logfile - check logfile on target volume
 * @vol:	volume on which to check logfile
 *
 * Return 0 on success and -1 on error with errno set error code.
 */
static int ntfs_volume_check_logfile(ntfs_volume *vol)
{
	ntfs_inode *ni;
	ntfs_attr *na = NULL;
	RESTART_PAGE_HEADER *rp = NULL;
	int err = 0;

	if ((ni = ntfs_inode_open(vol, FILE_LogFile)) == NULL) {
		ntfs_log_perror("Failed to open inode FILE_LogFile");
		errno = EIO;
		return -1;
	}
	if ((na = ntfs_attr_open(ni, AT_DATA, AT_UNNAMED, 0)) == NULL) {
		ntfs_log_perror("Failed to open $FILE_LogFile/$DATA");
		err = EIO;
		goto exit;
	}
	if (!ntfs_check_logfile(na, &rp) || !ntfs_is_logfile_clean(na, rp))
		err = EOPNOTSUPP;
	free(rp);
exit:
	if (na)
		ntfs_attr_close(na);
	ntfs_inode_close(ni);
	if (err) {
		errno = err;
		return -1;
	}
	return 0;
}

/**
 * ntfs_hiberfile_open - Find and open '/hiberfil.sys'
 * @vol:    An ntfs volume obtained from ntfs_mount
 *
 * Return:  inode  Success, hiberfil.sys is valid
 *	    NULL   hiberfil.sys doesn't exist or some other error occurred
 */
static ntfs_inode *ntfs_hiberfile_open(ntfs_volume *vol)
{
	u64 inode;
	ntfs_inode *ni_root;
	ntfs_inode *ni_hibr = NULL;
	ntfschar   *unicode = NULL;
	int unicode_len;
	const char *hiberfile = "hiberfil.sys";

	if (!vol) {
		errno = EINVAL;
		return NULL;
	}

	ni_root = ntfs_inode_open(vol, FILE_root);
	if (!ni_root) {
		ntfs_log_debug("Couldn't open the root directory.\n");
		return NULL;
	}

	unicode_len = ntfs_mbstoucs(hiberfile, &unicode, 0);
	if (unicode_len < 0) {
		ntfs_log_perror("Couldn't convert 'hiberfil.sys' to Unicode");
		goto out;
	}

	inode = ntfs_inode_lookup_by_name(ni_root, unicode, unicode_len);
	if (inode == (u64)-1) {
		ntfs_log_debug("Couldn't find file '%s'.\n", hiberfile);
		goto out;
	}

	inode = MREF(inode);
	ni_hibr = ntfs_inode_open(vol, inode);
	if (!ni_hibr) {
		ntfs_log_debug("Couldn't open inode %lld.\n", (long long)inode);
		goto out;
	}
out:
	ntfs_inode_close(ni_root);
	free(unicode);
	return ni_hibr;
}


#define NTFS_HIBERFILE_HEADER_SIZE	4096

/**
 * ntfs_volume_check_hiberfile - check hiberfil.sys whether Windows is
 *                               hibernated on the target volume
 * @vol:    volume on which to check hiberfil.sys
 *
 * Return:  0 if Windows isn't hibernated for sure
 *         -1 otherwise and errno is set to the appropriate value
 */
static int ntfs_volume_check_hiberfile(ntfs_volume *vol)
{
	ntfs_inode *ni;
	ntfs_attr *na = NULL;
	int i, bytes_read, ret = -1;
	char *buf = NULL;

	ni = ntfs_hiberfile_open(vol);
	if (!ni) {
		if (errno == ENOENT)
			return 0;
		return -1;
	}

	buf = ntfs_malloc(NTFS_HIBERFILE_HEADER_SIZE);
	if (!buf)
		goto out;

	na = ntfs_attr_open(ni, AT_DATA, AT_UNNAMED, 0);
	if (!na) {
		ntfs_log_perror("Failed to open hiberfil.sys data attribute");
		goto out;
	}

	bytes_read = ntfs_attr_pread(na, 0, NTFS_HIBERFILE_HEADER_SIZE, buf);
	if (bytes_read == -1) {
		ntfs_log_perror("Failed to read hiberfil.sys");
		goto out;
	}
	if (bytes_read < NTFS_HIBERFILE_HEADER_SIZE) {
		ntfs_log_error("Hibernated non-system partition, refused to "
			       "mount.\n");
		errno = EPERM;
		goto out;
	}
	if (memcmp(buf, "hibr", 4) == 0) {
		ntfs_log_error("Windows is hibernated, refused to mount.\n");
		errno = EPERM;
		goto out;
	}
	for (i = 0; i < NTFS_HIBERFILE_HEADER_SIZE; i++) {
		if (buf[i]) {
			ntfs_log_error("Windows is hibernated, won't mount.\n");
			errno = EPERM;
			goto out;
		}
	}
        /* All right, all header bytes are zero */
	ret = 0;
out:
	if (na)
		ntfs_attr_close(na);
	free(buf);
	ntfs_inode_close(ni);
	return ret;
}

/**
 * ntfs_device_mount - open ntfs volume
 * @dev:	device to open
 * @flags:	optional mount flags
 *
 * This function mounts an ntfs volume. @dev should describe the device which
 * to mount as the ntfs volume.
 *
 * @flags is an optional second parameter. The same flags are used as for
 * the mount system call (man 2 mount). Currently only the following flags
 * are implemented:
 *	MS_RDONLY	- mount volume read-only
 *	MS_NOATIME	- do not update access time
 *
 * The function opens the device @dev and verifies that it contains a valid
 * bootsector. Then, it allocates an ntfs_volume structure and initializes
 * some of the values inside the structure from the information stored in the
 * bootsector. It proceeds to load the necessary system files and completes
 * setting up the structure.
 *
 * Return the allocated volume structure on success and NULL on error with
 * errno set to the error code.
 */
ntfs_volume *ntfs_device_mount(struct ntfs_device *dev, unsigned long flags)
{
	s64 l;
#ifdef DEBUG
	const char *OK = "OK\n";
	const char *FAILED = "FAILED\n";
#endif	
	ntfs_volume *vol;
	u8 *m = NULL, *m2 = NULL;
	ntfs_attr_search_ctx *ctx = NULL;
	ntfs_inode *ni;
	ntfs_attr *na;
	ATTR_RECORD *a;
	VOLUME_INFORMATION *vinf;
	ntfschar *vname;
	int i, j, eo;
	u32 u;

	vol = ntfs_volume_startup(dev, flags);
	if (!vol) {
		ntfs_log_perror("Failed to startup volume");
		return NULL;
	}

	/* Load data from $MFT and $MFTMirr and compare the contents. */
	m  = ntfs_malloc(vol->mftmirr_size << vol->mft_record_size_bits);
	m2 = ntfs_malloc(vol->mftmirr_size << vol->mft_record_size_bits);
	if (!m || !m2)
		goto error_exit;

	l = ntfs_attr_mst_pread(vol->mft_na, 0, vol->mftmirr_size,
			vol->mft_record_size, m);
	if (l != vol->mftmirr_size) {
		if (l == -1)
			ntfs_log_perror("Failed to read $MFT");
		else {
			ntfs_log_error("Failed to read $MFT, unexpected length "
				       "(%lld != %d).\n", (long long)l,
				       vol->mftmirr_size);
			errno = EIO;
		}
		goto error_exit;
	}
	l = ntfs_attr_mst_pread(vol->mftmirr_na, 0, vol->mftmirr_size,
			vol->mft_record_size, m2);
	if (l != vol->mftmirr_size) {
		if (l == 4)
			vol->mftmirr_size = 4;
		else {
			if (l == -1)
				ntfs_log_perror("Failed to read $MFTMirr");
			else {
				ntfs_log_error("Failed to read $MFTMirr "
					       "unexpected length (%d != %lld)."
					       "\n", vol->mftmirr_size,
					       (long long)l);
				errno = EIO;
			}
			goto error_exit;
		}
	}
	ntfs_log_debug("Comparing $MFTMirr to $MFT... ");
	for (i = 0; i < vol->mftmirr_size; ++i) {
		MFT_RECORD *mrec, *mrec2;
		const char *ESTR[12] = { "$MFT", "$MFTMirr", "$LogFile",
			"$Volume", "$AttrDef", "root directory", "$Bitmap",
			"$Boot", "$BadClus", "$Secure", "$UpCase", "$Extend" };
		const char *s;

		if (i < 12)
			s = ESTR[i];
		else if (i < 16)
			s = "system file";
		else
			s = "mft record";

		mrec = (MFT_RECORD*)(m + i * vol->mft_record_size);
		if (mrec->flags & MFT_RECORD_IN_USE) {
			if (ntfs_is_baad_recordp(mrec)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_error("$MFT error: Incomplete multi "
					       "sector transfer detected in "
					       "'%s'.\n", s);
				goto io_error_exit;
			}
			if (!ntfs_is_mft_recordp(mrec)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_error("$MFT error: Invalid mft "
						"record for '%s'.\n", s);
				goto io_error_exit;
			}
		}
		mrec2 = (MFT_RECORD*)(m2 + i * vol->mft_record_size);
		if (mrec2->flags & MFT_RECORD_IN_USE) {
			if (ntfs_is_baad_recordp(mrec2)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_error("$MFTMirr error: Incomplete "
						"multi sector transfer "
						"detected in '%s'.\n", s);
				goto io_error_exit;
			}
			if (!ntfs_is_mft_recordp(mrec2)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_error("$MFTMirr error: Invalid mft "
						"record for '%s'.\n", s);
				goto io_error_exit;
			}
		}
		if (memcmp(mrec, mrec2, ntfs_mft_record_get_data_size(mrec))) {
			ntfs_log_debug(FAILED);
			ntfs_log_error("$MFTMirr does not match $MFT (record "
				       "%d).\n", i);
			goto io_error_exit;
		}
	}
	ntfs_log_debug(OK);

	free(m2);
	free(m);
	m = m2 = NULL;

	/* Now load the bitmap from $Bitmap. */
	ntfs_log_debug("Loading $Bitmap... ");
	vol->lcnbmp_ni = ntfs_inode_open(vol, FILE_Bitmap);
	if (!vol->lcnbmp_ni) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to open inode");
		goto error_exit;
	}
	/* Get an ntfs attribute for $Bitmap/$DATA. */
	vol->lcnbmp_na = ntfs_attr_open(vol->lcnbmp_ni, AT_DATA, AT_UNNAMED, 0);
	if (!vol->lcnbmp_na) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to open ntfs attribute");
		goto error_exit;
	}
	/* Done with the $Bitmap mft record. */
	ntfs_log_debug(OK);

	/* Now load the upcase table from $UpCase. */
	ntfs_log_debug("Loading $UpCase... ");
	ni = ntfs_inode_open(vol, FILE_UpCase);
	if (!ni) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to open inode");
		goto error_exit;
	}
	/* Get an ntfs attribute for $UpCase/$DATA. */
	na = ntfs_attr_open(ni, AT_DATA, AT_UNNAMED, 0);
	if (!na) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to open ntfs attribute");
		goto error_exit;
	}
	/*
	 * Note: Normally, the upcase table has a length equal to 65536
	 * 2-byte Unicode characters but allow for different cases, so no
	 * checks done. Just check we don't overflow 32-bits worth of Unicode
	 * characters.
	 */
	if (na->data_size & ~0x1ffffffffULL) {
		ntfs_log_debug(FAILED);
		ntfs_log_error("Error: Upcase table is too big (max 32-bit "
				"allowed).\n");
		errno = EINVAL;
		goto error_exit;
	}
	if (vol->upcase_len != na->data_size >> 1) {
		vol->upcase_len = na->data_size >> 1;
		/* Throw away default table. */
		free(vol->upcase);
		vol->upcase = ntfs_malloc(na->data_size);
		if (!vol->upcase) {
			ntfs_log_debug(FAILED);
			goto error_exit;
		}
	}
	/* Read in the $DATA attribute value into the buffer. */
	l = ntfs_attr_pread(na, 0, na->data_size, vol->upcase);
	if (l != na->data_size) {
		ntfs_log_debug(FAILED);
		ntfs_log_error("Failed to read $UpCase, unexpected length "
			       "(%lld != %lld).\n", (long long)l,
			       (long long)na->data_size);
		errno = EIO;
		goto error_exit;
	}
	/* Done with the $UpCase mft record. */
	ntfs_log_debug(OK);
	ntfs_attr_close(na);
	if (ntfs_inode_close(ni))
		ntfs_log_perror("Failed to close inode, leaking memory");

	/*
	 * Now load $Volume and set the version information and flags in the
	 * vol structure accordingly.
	 */
	ntfs_log_debug("Loading $Volume... ");
	vol->vol_ni = ntfs_inode_open(vol, FILE_Volume);
	if (!vol->vol_ni) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to open inode");
		goto error_exit;
	}
	/* Get a search context for the $Volume/$VOLUME_INFORMATION lookup. */
	ctx = ntfs_attr_get_search_ctx(vol->vol_ni, NULL);
	if (!ctx) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("Failed to allocate attribute search context");
		goto error_exit;
	}
	/* Find the $VOLUME_INFORMATION attribute. */
	if (ntfs_attr_lookup(AT_VOLUME_INFORMATION, AT_UNNAMED, 0, 0, 0, NULL,
			0, ctx)) {
		ntfs_log_debug(FAILED);
		ntfs_log_perror("$VOLUME_INFORMATION attribute not found in "
				"$Volume");
		goto error_exit;
	}
	a = ctx->attr;
	/* Has to be resident. */
	if (a->non_resident) {
		ntfs_log_debug(FAILED);
		ntfs_log_error("Attribute $VOLUME_INFORMATION must be "
			       "resident but it isn't.\n");
		errno = EIO;
		goto error_exit;
	}
	/* Get a pointer to the value of the attribute. */
	vinf = (VOLUME_INFORMATION*)(le16_to_cpu(a->value_offset) + (char*)a);
	/* Sanity checks. */
	if ((char*)vinf + le32_to_cpu(a->value_length) > (char*)ctx->mrec +
			le32_to_cpu(ctx->mrec->bytes_in_use) ||
			le16_to_cpu(a->value_offset) + le32_to_cpu(
			a->value_length) > le32_to_cpu(a->length)) {
		ntfs_log_debug(FAILED);
		ntfs_log_error("$VOLUME_INFORMATION in $Volume is corrupt.\n");
		errno = EIO;
		goto error_exit;
	}
	/* Setup vol from the volume information attribute value. */
	vol->major_ver = vinf->major_ver;
	vol->minor_ver = vinf->minor_ver;
	/* Do not use le16_to_cpu() macro here as our VOLUME_FLAGS are
	   defined using cpu_to_le16() macro and hence are consistent. */
	vol->flags = vinf->flags;
	/*
	 * Reinitialize the search context for the $Volume/$VOLUME_NAME lookup.
	 */
	ntfs_attr_reinit_search_ctx(ctx);
	if (ntfs_attr_lookup(AT_VOLUME_NAME, AT_UNNAMED, 0, 0, 0, NULL, 0,
			ctx)) {
		if (errno != ENOENT) {
			ntfs_log_debug(FAILED);
			ntfs_log_perror("Failed to lookup of $VOLUME_NAME in "
					"$Volume failed");
			goto error_exit;
		}
		/*
		 * Attribute not present.  This has been seen in the field.
		 * Treat this the same way as if the attribute was present but
		 * had zero length.
		 */
		vol->vol_name = ntfs_malloc(1);
		if (!vol->vol_name) {
			ntfs_log_debug(FAILED);
			goto error_exit;
		}
		vol->vol_name[0] = '\0';
	} else {
		a = ctx->attr;
		/* Has to be resident. */
		if (a->non_resident) {
			ntfs_log_debug(FAILED);
			ntfs_log_error("$VOLUME_NAME must be resident.\n");
			errno = EIO;
			goto error_exit;
		}