volume.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

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	/*
	 * We now initialize the cluster allocator.
	 *
	 * FIXME: Move this to its own function? (AIA)
	 */

	// TODO: Make this tunable at mount time. (AIA)
	vol->mft_zone_multiplier = 1;

	/* Determine the size of the MFT zone. */
	mft_zone_size = vol->nr_clusters;
	switch (vol->mft_zone_multiplier) {  /* % of volume size in clusters */
	case 4:
		mft_zone_size >>= 1;			/* 50%   */
		break;
	case 3:
		mft_zone_size = mft_zone_size * 3 >> 3;	/* 37.5% */
		break;
	case 2:
		mft_zone_size >>= 2;			/* 25%   */
		break;
	/* case 1: */
	default:
		mft_zone_size >>= 3;			/* 12.5% */
		break;
	}

	/* 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);

	/*
	 * 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_debug("Failed to open inode FILE_LogFile.\n");
		errno = EIO;
		return -1;
	}
	if ((na = ntfs_attr_open(ni, AT_DATA, AT_UNNAMED, 0)) == NULL) {
		ntfs_log_debug("Failed to open $FILE_LogFile/$DATA\n");
		err = EIO;
		goto exit;
	}
	if (!ntfs_check_logfile(na, &rp) || !ntfs_is_logfile_clean(na, rp))
		err = EOPNOTSUPP;
	if (rp)
		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 = malloc(NTFS_HIBERFILE_HEADER_SIZE);
	if (!buf) {
		ntfs_log_perror("Error allocating memory for hiberfile.sys header");
		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_debug("Hibernated non-system partition, refused to "
				"mount!\n");
		errno = EPERM;
		goto out;
	}
	if (memcmp(buf, "hibr", 4) == 0) {
		ntfs_log_debug("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_debug("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;
#ifndef NTFS_DISABLE_DEBUG_LOGGING
	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 = (u8*)malloc(vol->mftmirr_size << vol->mft_record_size_bits);
	m2 = (u8*)malloc(vol->mftmirr_size << vol->mft_record_size_bits);
	if (!m || !m2) {
		ntfs_log_perror("Failed to allocate memory");
		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_debug("Failed to read $MFT, unexpected length "
				       "(%d != %lld).\n", vol->mftmirr_size, l);
			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 == -1)
			ntfs_log_perror("Failed to read $MFTMirr");
		else {
			ntfs_log_debug("Failed to read $MFTMirr, unexpected "
				       "length (%d != %lld).\n", 
				       vol->mftmirr_size, 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_debug("$MFT error: Incomplete multi "
						"sector transfer detected in "
						"%s.\n", s);
				goto io_error_exit;
			}
			if (!ntfs_is_mft_recordp(mrec)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_debug("$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_debug("$MFTMirr error: Incomplete "
						"multi sector transfer "
						"detected in %s.\n", s);
				goto io_error_exit;
			}
			if (!ntfs_is_mft_recordp(mrec2)) {
				ntfs_log_debug("FAILED\n");
				ntfs_log_debug("$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_debug("$MFTMirr does not match $MFT. Run "
					"chkdsk.\n");
			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_debug("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 = (ntfschar*)malloc(na->data_size);
		if (!vol->upcase) {
			ntfs_log_debug(FAILED);
			ntfs_log_debug("Not enough memory to load $UpCase.\n");
			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_debug("Amount of data read does not correspond to expected "
				"length!\n");
		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.
	 */