win32_io.c

一个在linux下挂载ntfs文件系统的好工具

	}
	errno = ntfs_w32error_to_errno(GetLastError());
	ntfs_log_trace("Couldn't retrieve disk geometry.\n");
	fd->geo_cylinders = -1;
	fd->geo_sectors = -1;
	fd->geo_size = -1;
	return -1;
}

/**
 * ntfs_device_win32_open_file - open a file via win32 API
 * @filename:	name of the file to open
 * @fd:		pointer to win32 file device in which to put the result
 * @flags:	unix open status flags
 *
 * Return 0 if o.k.
 *	 -1 if not, and errno set.
 */
static __inline__ int ntfs_device_win32_open_file(char *filename, win32_fd *fd,
		int flags)
{
	HANDLE handle;

	if (ntfs_device_win32_simple_open_file(filename, &handle, flags,
			FALSE)) {
		/* open error */
		return -1;
	}
	/* fill fd */
	fd->handle = handle;
	fd->part_start = 0;
	fd->part_length = ntfs_device_win32_getsize(handle);
	fd->pos = 0;
	fd->part_hidden_sectors = -1;
	fd->geo_size = -1;	/* used as a marker that this is a file */
	fd->vol_handle = INVALID_HANDLE_VALUE;
	return 0;
}

/**
 * ntfs_device_win32_open_drive - open a drive via win32 API
 * @drive_id:	drive to open
 * @fd:		pointer to win32 file device in which to put the result
 * @flags:	unix open status flags
 *
 * return 0 if o.k.
 *        -1 if not, and errno set.
 */
static __inline__ int ntfs_device_win32_open_drive(int drive_id, win32_fd *fd,
		int flags)
{
	HANDLE handle;
	int err;
	char filename[MAX_PATH];

	sprintf(filename, "\\\\.\\PhysicalDrive%d", drive_id);
	if ((err = ntfs_device_win32_simple_open_file(filename, &handle, flags,
			TRUE))) {
		/* open error */
		return err;
	}
	/* store the drive geometry */
	ntfs_device_win32_getgeo(handle, fd);
	/* Just to be sure */
	if (fd->geo_size == -1)
		fd->geo_size = ntfs_device_win32_getdisklength(handle);
	/* fill fd */
	fd->handle = handle;
	fd->part_start = 0;
	fd->part_length = fd->geo_size;
	fd->pos = 0;
	fd->part_hidden_sectors = -1;
	fd->vol_handle = INVALID_HANDLE_VALUE;
	return 0;
}

/**
 * ntfs_device_win32_open_volume_for_partition - find and open a volume
 *
 * Windows NT/2k/XP handles volumes instead of partitions.
 * This function gets the partition details and return an open volume handle.
 * That volume is the one whose only physical location on disk is the described
 * partition.
 *
 * The function required Windows 2k/XP, otherwise it fails (gracefully).
 *
 * Return success: a valid open volume handle.
 *        fail   : INVALID_HANDLE_VALUE
 */
static HANDLE ntfs_device_win32_open_volume_for_partition(unsigned int drive_id,
		s64 part_offset, s64 part_length, int flags)
{
	HANDLE vol_find_handle;
	TCHAR vol_name[MAX_PATH];

	/* Make sure all the required imports exist. */
	if (!fnFindFirstVolume || !fnFindNextVolume || !fnFindVolumeClose) {
		ntfs_log_trace("Required dll imports not found.\n");
		return INVALID_HANDLE_VALUE;
	}
	/* Start iterating through volumes. */
	ntfs_log_trace("Entering with drive_id=%d, part_offset=%lld, "
			"path_length=%lld, flags=%d.\n", drive_id,
			(unsigned long long)part_offset,
			(unsigned long long)part_length, flags);
	vol_find_handle = fnFindFirstVolume(vol_name, MAX_PATH);
	/* If a valid handle could not be aquired, reply with "don't know". */
	if (vol_find_handle == INVALID_HANDLE_VALUE) {
		ntfs_log_trace("FindFirstVolume failed.\n");
		return INVALID_HANDLE_VALUE;
	}
	do {
		int vol_name_length;
		HANDLE handle;

		/* remove trailing '/' from vol_name */
#ifdef UNICODE
		vol_name_length = wcslen(vol_name);
#else
		vol_name_length = strlen(vol_name);
#endif
		if (vol_name_length>0)
			vol_name[vol_name_length-1]=0;

		ntfs_log_debug("Processing %s.\n", vol_name);
		/* open the file */
		handle = CreateFile(vol_name,
				ntfs_device_unix_status_flags_to_win32(flags),
				FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
				OPEN_EXISTING, 0, NULL);
		if (handle != INVALID_HANDLE_VALUE) {
			DWORD bytesReturned;
#define EXTENTS_SIZE sizeof(VOLUME_DISK_EXTENTS) + 9 * sizeof(DISK_EXTENT)
			char extents[EXTENTS_SIZE];

			/* Check physical locations. */
			if (DeviceIoControl(handle,
					IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,
					NULL, 0, extents, EXTENTS_SIZE,
					&bytesReturned, NULL)) {
				if (((VOLUME_DISK_EXTENTS *)extents)->
						NumberOfDiskExtents == 1) {
					DISK_EXTENT *extent = &((
							VOLUME_DISK_EXTENTS *)
							extents)->Extents[0];
					if ((extent->DiskNumber==drive_id) &&
							(extent->StartingOffset.
							QuadPart==part_offset)
							&& (extent->
							ExtentLength.QuadPart
							== part_length)) {
						/*
						 * Eureka! (Archimedes, 287 BC,
						 * "I have found it!")
						 */
						fnFindVolumeClose(
							vol_find_handle);
						return handle;
					}
				}
			}
		} else
			ntfs_log_trace("getExtents() Failed.\n");
	} while (fnFindNextVolume(vol_find_handle, vol_name, MAX_PATH));
	/* End of iteration through volumes. */
	ntfs_log_trace("Closing, volume was not found.\n");
	fnFindVolumeClose(vol_find_handle);
	return INVALID_HANDLE_VALUE;
}

/**
 * ntfs_device_win32_find_partition - locates partition details by id.
 * @handle:		HANDLE to the PhysicalDrive
 * @partition_id:	the partition number to locate
 * @part_offset:	pointer to where to put the offset to the partition
 * @part_length:	pointer to where to put the length of the partition
 * @hidden_sectors:	pointer to where to put the hidden sectors
 *
 * This function requires an open PhysicalDrive handle and a partition_id.
 * If a partition with the required id is found on the supplied device,
 * the partition attributes are returned back.
 *
 * Returns: TRUE  if found, and sets the output parameters.
 *          FALSE if not and errno is set to the error code.
 */
static BOOL ntfs_device_win32_find_partition(HANDLE handle, DWORD partition_id,
		s64 *part_offset, s64 *part_length, int *hidden_sectors)
{
	DRIVE_LAYOUT_INFORMATION *drive_layout;
	unsigned int err, buf_size, part_count;
	DWORD i;

	/*
	 * There is no way to know the required buffer, so if the ioctl fails,
	 * try doubling the buffer size each time until the ioctl succeeds.
	 */
	part_count = 8;
	do {
		buf_size = sizeof(DRIVE_LAYOUT_INFORMATION) +
				part_count * sizeof(PARTITION_INFORMATION);
		drive_layout = malloc(buf_size);
		if (!drive_layout) {
			errno = ENOMEM;
			return FALSE;
		}
		if (DeviceIoControl(handle, IOCTL_DISK_GET_DRIVE_LAYOUT, NULL,
				0, (BYTE*)drive_layout, buf_size, &i, NULL))
			break;
		err = GetLastError();
		free(drive_layout);
		if (err != ERROR_INSUFFICIENT_BUFFER) {
			ntfs_log_trace("GetDriveLayout failed.\n");
			errno = ntfs_w32error_to_errno(err);
			return FALSE;
		}
		ntfs_log_debug("More than %u partitions.\n", part_count);
		part_count <<= 1;
		if (part_count > 512) {
			ntfs_log_trace("GetDriveLayout failed: More than 512 "
					"partitions?\n");
			errno = ENOBUFS;
			return FALSE;
		}
	} while (1);
	for (i = 0; i < drive_layout->PartitionCount; i++) {
		if (drive_layout->PartitionEntry[i].PartitionNumber ==
				partition_id) {
			*part_offset = drive_layout->PartitionEntry[i].
					StartingOffset.QuadPart;
			*part_length = drive_layout->PartitionEntry[i].
					PartitionLength.QuadPart;
			*hidden_sectors = drive_layout->PartitionEntry[i].
					HiddenSectors;
			free(drive_layout);
			return TRUE;
		}
	}
	free(drive_layout);
	errno = ENOENT;
	return FALSE;
}

/**
 * ntfs_device_win32_open_partition - open a partition via win32 API
 * @drive_id:		drive to open
 * @partition_id:	partition to open
 * @fd:			win32 file device to return
 * @flags:		unix open status flags
 *
 * Return  0 if o.k.
 *        -1 if not, and errno set.
 *
 * When fails, fd contents may have not been preserved.
 */
static int ntfs_device_win32_open_partition(int drive_id,
		unsigned int partition_id, win32_fd *fd, int flags)
{
	s64 part_start, part_length;
	HANDLE handle;
	int err, hidden_sectors;
	char drive_name[MAX_PATH];

	sprintf(drive_name, "\\\\.\\PhysicalDrive%d", drive_id);
	/* Open the entire device without locking, ask questions later */
	if ((err = ntfs_device_win32_simple_open_file(drive_name, &handle,
			flags, FALSE))) {
		/* error */
		return err;
	}
	if (ntfs_device_win32_find_partition(handle, partition_id, &part_start,
			&part_length, &hidden_sectors)) {
		s64 tmp;
		HANDLE vol_handle = ntfs_device_win32_open_volume_for_partition(
			drive_id, part_start, part_length, flags);
		/* Store the drive geometry. */
		ntfs_device_win32_getgeo(handle, fd);
		fd->handle = handle;
		fd->pos = 0;
		fd->part_start = part_start;
		fd->part_length = part_length;
		fd->part_hidden_sectors = hidden_sectors;
		tmp = ntfs_device_win32_getntfssize(vol_handle);
		if (tmp > 0)
			fd->geo_size = tmp;
		else
			fd->geo_size = fd->part_length;
		if (vol_handle != INVALID_HANDLE_VALUE) {
			if (((flags & O_RDWR) == O_RDWR) &&
					ntfs_device_win32_lock(vol_handle)) {
				CloseHandle(vol_handle);
				CloseHandle(handle);
				return -1;
			}
			fd->vol_handle = vol_handle;
		} else {
			if ((flags & O_RDWR) == O_RDWR) {
				/* Access if read-write, no volume found. */
				ntfs_log_trace("Partitions containing Spanned/"
						"Mirrored volumes are not "
						"supported in R/W status "
						"yet.\n");
				CloseHandle(handle);
				errno = EOPNOTSUPP;
				return -1;
			}
			fd->vol_handle = INVALID_HANDLE_VALUE;
		}
		return 0;
	} else {
		ntfs_log_debug("Partition %u not found on drive %d.\n",
				partition_id, drive_id);
		CloseHandle(handle);
		errno = ENODEV;
		return -1;
	}
}

/**
 * ntfs_device_win32_open - open a device
 * @dev:	a pointer to the NTFS_DEVICE to open
 * @flags:	unix open status flags
 *
 * @dev->d_name must hold the device name, the rest is ignored.
 * Supported flags are O_RDONLY, O_WRONLY and O_RDWR.
 *
 * If name is in format "(hd[0-9],[0-9])" then open a partition.
 * If name is in format "(hd[0-9])" then open a volume.
 * Otherwise open a file.
 */
static int ntfs_device_win32_open(struct ntfs_device *dev, int flags)
{
	int drive_id = 0, numparams;
	unsigned int part = 0;
	char drive_char;
	win32_fd fd;
	int err;

	if (NDevOpen(dev)) {
		errno = EBUSY;
		return -1;
	}
	ntfs_device_win32_init_imports();
	numparams = sscanf(dev->d_name, "/dev/hd%c%u", &drive_char, &part);
	drive_id = toupper(drive_char) - 'A';
	switch (numparams) {
	case 0:
		ntfs_log_debug("win32_open(%s) -> file.\n", dev->d_name);
		err = ntfs_device_win32_open_file(dev->d_name, &fd, flags);
		break;
	case 1:
		ntfs_log_debug("win32_open(%s) -> drive %d.\n", dev->d_name,
				drive_id);
		err = ntfs_device_win32_open_drive(drive_id, &fd, flags);
		break;
	case 2:
		ntfs_log_debug("win32_open(%s) -> drive %d, part %u.\n",
				dev->d_name, drive_id, part);
		err = ntfs_device_win32_open_partition(drive_id, part, &fd,
				flags);
		break;
	default:
		ntfs_log_debug("win32_open(%s) -> unknwon file format.\n",
				dev->d_name);
		err = -1;
	}
	if (err)
		return err;
	ntfs_log_debug("win32_open(%s) -> %p, offset 0x%llx.\n", dev->d_name,
			dev, fd.part_start);
	/* Setup our read-only flag. */
	if ((flags & O_RDWR) != O_RDWR)
		NDevSetReadOnly(dev);
	dev->d_private = malloc(sizeof(win32_fd));
	memcpy(dev->d_private, &fd, sizeof(win32_fd));
	NDevSetOpen(dev);
	NDevClearDirty(dev);
	return 0;
}

/**
 * ntfs_device_win32_seek - change current logical file position
 * @dev:	ntfs device obtained via ->open
 * @offset:	required offset from the whence anchor
 * @whence:	whence anchor specifying what @offset is relative to
 *
 * Return the new position on the volume on success and -1 on error with errno
 * set to the error code.
 *
 * @whence may be one of the following:
 *	SEEK_SET - Offset is relative to file start.
 *	SEEK_CUR - Offset is relative to current position.
 *	SEEK_END - Offset is relative to end of file.
 */
static s64 ntfs_device_win32_seek(struct ntfs_device *dev, s64 offset,
		int whence)
{
	s64 abs_ofs;
	win32_fd *fd = (win32_fd *)dev->d_private;

	ntfs_log_trace("seek offset = 0x%llx, whence = %d.\n", offset, whence);
	switch (whence) {
	case SEEK_SET:
		abs_ofs = offset;
		break;
	case SEEK_CUR:
		abs_ofs = fd->pos + offset;
		break;
	case SEEK_END:
		/* End of partition != end of disk. */
		if (fd->part_length == -1) {
			ntfs_log_trace("Position relative to end of disk not "
					"implemented.\n");
			errno = EOPNOTSUPP;
			return -1;
		}
		abs_ofs = fd->part_length + offset;
		break;
	default:
		ntfs_log_trace("Wrong mode %d.\n", whence);
		errno = EINVAL;
		return -1;
	}
	if (abs_ofs < 0 || abs_ofs > fd->part_length) {
		ntfs_log_trace("Seeking outsize seekable area.\n");
		errno = EINVAL;
		return -1;
	}
	fd->pos = abs_ofs;
	return abs_ofs;
}

/**
 * ntfs_device_win32_pio - positioned low level i/o
 * @fd:		win32 device descriptor obtained via ->open
 * @pos:	at which position to do i/o from/to
 * @count:	how many bytes should be transfered
 * @b:		source/destination buffer
 * @write:	TRUE if write transfer and FALSE if read transfer
 *
 * On success returns the number of bytes transfered (can be < @count) and on
 * error returns -1 and errno set.  Transfer starts from position @pos on @fd.
 *
 * Notes:
 *	- @pos, @buf, and @count must be aligned to NTFS_BLOCK_SIZE.
 *	- When dealing with volumes, a single call must not span both volume
 *	  and disk extents.
 *	- Does not use/set @fd->pos.
 */
static s64 ntfs_device_win32_pio(win32_fd *fd, const s64 pos,
		const s64 count, void *b, const BOOL write)
{
	LARGE_INTEGER li;
	HANDLE handle;
	DWORD bt;
	BOOL res;

	ntfs_log_trace("pos = 0x%llx, count = 0x%llx, direction = %s.\n",
			(long long)pos, (long long)count, write ? "write" :
			"read");
	li.QuadPart = pos;
	if (fd->vol_handle != INVALID_HANDLE_VALUE && pos < fd->geo_size) {
		ntfs_log_debug("Transfering via vol_handle.\n");
		handle = fd->vol_handle;
	} else {
		ntfs_log_debug("Transfering via handle.\n");
		handle = fd->handle;
		li.QuadPart += fd->part_start;
	}
	if (!fnSetFilePointerEx(handle, li, NULL, FILE_BEGIN)) {
		errno = ntfs_w32error_to_errno(GetLastError());
		ntfs_log_trace("SetFilePointer failed.\n");
		return -1;
	}
	if (write)
		res = WriteFile(handle, b, count, &bt, NULL);
	else
		res = ReadFile(handle, b, count, &bt, NULL);
	if (!res) {
		errno = ntfs_w32error_to_errno(GetLastError());
		ntfs_log_trace("%sFile() failed.\n", write ? "Write" : "Read");
		return -1;
	}
	return bt;
}

/**
 * ntfs_device_win32_pread_simple - positioned simple read
 * @fd:		win32 device descriptor obtained via ->open
 * @pos:	at which position to read from
 * @count:	how many bytes should be read
 * @b:		a pointer to where to put the contents
 *