minidlna support now Samsung TV C550/C650 (thx amir909)

[tomato.git] / release / src / router / ntfs-3g / libntfs-3g / win32_io.c

/*
 * win32_io.c - A stdio-like disk I/O implementation for low-level disk access
 *              on Win32.  Can access an NTFS volume while it is mounted.
 *              Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2003-2004 Lode Leroy
 * Copyright (c) 2003-2006 Anton Altaparmakov
 * Copyright (c) 2004-2005 Yuval Fledel
 *
 * 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
 */

#include "config.h"

#ifdef HAVE_WINDOWS_H
#include <windows.h>
#endif
#include <winioctl.h>

#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

/* Prevent volume.h from being be loaded, as it conflicts with winnt.h. */
#define _NTFS_VOLUME_H
struct ntfs_volume;
typedef struct ntfs_volume ntfs_volume;

#include "debug.h"
#include "types.h"
#include "device.h"

#ifndef MAX_PATH
#define MAX_PATH 1024
#endif

#ifndef NTFS_BLOCK_SIZE
#define NTFS_BLOCK_SIZE         512
#define NTFS_BLOCK_SIZE_BITS    9
#endif

#ifndef IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS
#define IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS 5636096
#endif

/* Windows 2k+ imports. */
typedef HANDLE (WINAPI *LPFN_FINDFIRSTVOLUME)(LPTSTR, DWORD);
typedef BOOL (WINAPI *LPFN_FINDNEXTVOLUME)(HANDLE, LPTSTR, DWORD);
typedef BOOL (WINAPI *LPFN_FINDVOLUMECLOSE)(HANDLE);
typedef BOOL (WINAPI *LPFN_SETFILEPOINTEREX)(HANDLE, LARGE_INTEGER,
                PLARGE_INTEGER, DWORD);

static LPFN_FINDFIRSTVOLUME fnFindFirstVolume = NULL;
static LPFN_FINDNEXTVOLUME fnFindNextVolume = NULL;
static LPFN_FINDVOLUMECLOSE fnFindVolumeClose = NULL;
static LPFN_SETFILEPOINTEREX fnSetFilePointerEx = NULL;

#ifdef UNICODE
#define FNPOSTFIX "W"
#else
#define FNPOSTFIX "A"
#endif

/**
 * struct win32_fd -
 */
typedef struct {
        HANDLE handle;
        s64 pos;                /* Logical current position on the volume. */
        s64 part_start;
        s64 part_length;
        int part_hidden_sectors;
        s64 geo_size, geo_cylinders;
        DWORD geo_sectors, geo_heads;
        HANDLE vol_handle;
} win32_fd;

/**
 * ntfs_w32error_to_errno - convert a win32 error code to the unix one
 * @w32error:   the win32 error code
 *
 * Limited to a relatively small but useful number of codes.
 */
static int ntfs_w32error_to_errno(unsigned int w32error)
{
        ntfs_log_trace("Converting w32error 0x%x.\n",w32error);
        switch (w32error) {
                case ERROR_INVALID_FUNCTION:
                        return EBADRQC;
                case ERROR_FILE_NOT_FOUND:
                case ERROR_PATH_NOT_FOUND:
                case ERROR_INVALID_NAME:
                        return ENOENT;
                case ERROR_TOO_MANY_OPEN_FILES:
                        return EMFILE;
                case ERROR_ACCESS_DENIED:
                        return EACCES;
                case ERROR_INVALID_HANDLE:
                        return EBADF;
                case ERROR_NOT_ENOUGH_MEMORY:
                        return ENOMEM;
                case ERROR_OUTOFMEMORY:
                        return ENOSPC;
                case ERROR_INVALID_DRIVE:
                case ERROR_BAD_UNIT:
                        return ENODEV;
                case ERROR_WRITE_PROTECT:
                        return EROFS;
                case ERROR_NOT_READY:
                case ERROR_SHARING_VIOLATION:
                        return EBUSY;
                case ERROR_BAD_COMMAND:
                        return EINVAL;
                case ERROR_SEEK:
                case ERROR_NEGATIVE_SEEK:
                        return ESPIPE;
                case ERROR_NOT_SUPPORTED:
                        return EOPNOTSUPP;
                case ERROR_BAD_NETPATH:
                        return ENOSHARE;
                default:
                        /* generic message */
                        return ENOMSG;
        }
}

/**
 * libntfs_SetFilePointerEx - emulation for SetFilePointerEx()
 *
 * We use this to emulate SetFilePointerEx() when it is not present.  This can
 * happen since SetFilePointerEx() only exists in Win2k+.
 */
static BOOL WINAPI libntfs_SetFilePointerEx(HANDLE hFile,
                LARGE_INTEGER liDistanceToMove,
                PLARGE_INTEGER lpNewFilePointer, DWORD dwMoveMethod)
{
        liDistanceToMove.LowPart = SetFilePointer(hFile,
                        liDistanceToMove.LowPart, &liDistanceToMove.HighPart,
                        dwMoveMethod);
        if (liDistanceToMove.LowPart == INVALID_SET_FILE_POINTER &&
                        GetLastError() != NO_ERROR) {
                if (lpNewFilePointer)
                        lpNewFilePointer->QuadPart = -1;
                return FALSE;
        }
        if (lpNewFilePointer)
                lpNewFilePointer->QuadPart = liDistanceToMove.QuadPart;
        return TRUE;
}

/**
 * ntfs_device_win32_init_imports - initialize the function pointers
 *
 * The Find*Volume and SetFilePointerEx functions exist only on win2k+, as such
 * we cannot just staticly import them.
 *
 * This function initializes the imports if the functions do exist and in the
 * SetFilePointerEx case, we emulate the function ourselves if it is not
 * present.
 *
 * Note: The values are cached, do be afraid to run it more than once.
 */
static void ntfs_device_win32_init_imports(void)
{
        HMODULE kernel32 = GetModuleHandle("kernel32");
        if (!kernel32) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("kernel32.dll could not be imported.\n");
        }
        if (!fnSetFilePointerEx) {
                if (kernel32)
                        fnSetFilePointerEx = (LPFN_SETFILEPOINTEREX)
                                        GetProcAddress(kernel32,
                                        "SetFilePointerEx");
                /*
                 * If we did not get kernel32.dll or it is not Win2k+, emulate
                 * SetFilePointerEx().
                 */
                if (!fnSetFilePointerEx) {
                        ntfs_log_debug("SetFilePonterEx() not found in "
                                        "kernel32.dll: Enabling emulation.\n");
                        fnSetFilePointerEx = libntfs_SetFilePointerEx;
                }
        }
        /* Cannot do lookups if we could not get kernel32.dll... */
        if (!kernel32)
                return;
        if (!fnFindFirstVolume)
                fnFindFirstVolume = (LPFN_FINDFIRSTVOLUME)
                                GetProcAddress(kernel32, "FindFirstVolume"
                                FNPOSTFIX);
        if (!fnFindNextVolume)
                fnFindNextVolume = (LPFN_FINDNEXTVOLUME)
                                GetProcAddress(kernel32, "FindNextVolume"
                                FNPOSTFIX);
        if (!fnFindVolumeClose)
                fnFindVolumeClose = (LPFN_FINDVOLUMECLOSE)
                                GetProcAddress(kernel32, "FindVolumeClose");
}

/**
 * ntfs_device_unix_status_flags_to_win32 - convert unix->win32 open flags
 * @flags:      unix open status flags
 *
 * Supported flags are O_RDONLY, O_WRONLY and O_RDWR.
 */
static __inline__ int ntfs_device_unix_status_flags_to_win32(int flags)
{
        int win_mode;

        switch (flags & O_ACCMODE) {
        case O_RDONLY:
                win_mode = FILE_READ_DATA;
                break;
        case O_WRONLY:
                win_mode = FILE_WRITE_DATA;
                break;
        case O_RDWR:
                win_mode = FILE_READ_DATA | FILE_WRITE_DATA;
                break;
        default:
                /* error */
                ntfs_log_trace("Unknown status flags.\n");
                win_mode = 0;
        }
        return win_mode;
}


/**
 * ntfs_device_win32_simple_open_file - just open a file via win32 API
 * @filename:   name of the file to open
 * @handle:     pointer the a HANDLE in which to put the result
 * @flags:      unix open status flags
 * @locking:    will the function gain an exclusive lock on the file?
 *
 * Supported flags are O_RDONLY, O_WRONLY and O_RDWR.
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.  In this case handle is trashed.
 */
static int ntfs_device_win32_simple_open_file(const char *filename,
                HANDLE *handle, int flags, BOOL locking)
{
        *handle = CreateFile(filename,
                        ntfs_device_unix_status_flags_to_win32(flags),
                        locking ? 0 : (FILE_SHARE_WRITE | FILE_SHARE_READ),
                        NULL, OPEN_EXISTING, 0, NULL);
        if (*handle == INVALID_HANDLE_VALUE) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("CreateFile(%s) failed.\n", filename);
                return -1;
        }
        return 0;
}

/**
 * ntfs_device_win32_lock - lock the volume
 * @handle:     a win32 HANDLE for a volume to lock
 *
 * Locking a volume means no one can access its contents.
 * Exiting the process automatically unlocks the volume, except in old NT4s.
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.
 */
static int ntfs_device_win32_lock(HANDLE handle)
{
        DWORD i;

        if (!DeviceIoControl(handle, FSCTL_LOCK_VOLUME, NULL, 0, NULL, 0, &i,
                        NULL)) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't lock volume.\n");
                return -1;
        }
        ntfs_log_debug("Volume locked.\n");
        return 0;
}

/**
 * ntfs_device_win32_unlock - unlock the volume
 * @handle:     the win32 HANDLE which the volume was locked with
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.
 */
static int ntfs_device_win32_unlock(HANDLE handle)
{
        DWORD i;

        if (!DeviceIoControl(handle, FSCTL_UNLOCK_VOLUME, NULL, 0, NULL, 0, &i,
                        NULL)) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't unlock volume.\n");
                return -1;
        }
        ntfs_log_debug("Volume unlocked.\n");
        return 0;
}

/**
 * ntfs_device_win32_dismount - dismount a volume
 * @handle:     a win32 HANDLE for a volume to dismount
 *
 * Dismounting means the system will refresh the volume in the first change it
 * gets.  Usefull after altering the file structures.
 * The volume must be locked by the current process while dismounting.
 * A side effect is that the volume is also unlocked, but you must not rely om
 * this.
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.
 */
static int ntfs_device_win32_dismount(HANDLE handle)
{
        DWORD i;

        if (!DeviceIoControl(handle, FSCTL_DISMOUNT_VOLUME, NULL, 0, NULL, 0,
                        &i, NULL)) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't dismount volume.\n");
                return -1;
        }
        ntfs_log_debug("Volume dismounted.\n");
        return 0;
}

/**
 * ntfs_device_win32_getsize - get file size via win32 API
 * @handle:     pointer the file HANDLE obtained via open
 *
 * Only works on ordinary files.
 *
 * Return The file size if o.k.
 *       -1 if not, and errno set.
 */
static s64 ntfs_device_win32_getsize(HANDLE handle)
{
        DWORD loword, hiword;

        loword = GetFileSize(handle, &hiword);
        if (loword == INVALID_FILE_SIZE) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't get file size.\n");
                return -1;
        }
        return ((s64)hiword << 32) + loword;
}

/**
 * ntfs_device_win32_getdisklength - get disk size via win32 API
 * @handle:     pointer the file HANDLE obtained via open
 * @argp:       pointer to result buffer
 *
 * Only works on PhysicalDriveX type handles.
 *
 * Return The disk size if o.k.
 *       -1 if not, and errno set.
 */
static s64 ntfs_device_win32_getdisklength(HANDLE handle)
{
        GET_LENGTH_INFORMATION buf;
        DWORD i;

        if (!DeviceIoControl(handle, IOCTL_DISK_GET_LENGTH_INFO, NULL, 0, &buf,
                        sizeof(buf), &i, NULL)) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't get disk length.\n");
                return -1;
        }
        ntfs_log_debug("Disk length: %lld.\n", buf.Length.QuadPart);
        return buf.Length.QuadPart;
}

/**
 * ntfs_device_win32_getntfssize - get NTFS volume size via win32 API
 * @handle:     pointer the file HANDLE obtained via open
 * @argp:       pointer to result buffer
 *
 * Only works on NTFS volume handles.
 * An annoying bug in windows is that an NTFS volume does not occupy the entire
 * partition, namely not the last sector (which holds the backup boot sector,
 * and normally not interesting).
 * Use this function to get the length of the accessible space through a given
 * volume handle.
 *
 * Return The volume size if o.k.
 *       -1 if not, and errno set.
 */
static s64 ntfs_device_win32_getntfssize(HANDLE handle)
{
        s64 rvl;
#ifdef FSCTL_GET_NTFS_VOLUME_DATA
        DWORD i;
        NTFS_VOLUME_DATA_BUFFER buf;

        if (!DeviceIoControl(handle, FSCTL_GET_NTFS_VOLUME_DATA, NULL, 0, &buf,
                        sizeof(buf), &i, NULL)) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("Couldn't get NTFS volume length.\n");
                return -1;
        }
        rvl = buf.NumberSectors.QuadPart * buf.BytesPerSector;
        ntfs_log_debug("NTFS volume length: 0x%llx.\n", (long long)rvl);
#else
        errno = EINVAL;
        rvl = -1;
#endif
        return rvl;
}

/**
 * ntfs_device_win32_getgeo - get CHS information of a drive
 * @handle:     an open handle to the PhysicalDevice
 * @fd:         a win_fd structure that will be filled
 *
 * Return 0 if o.k.
 *       -1 if not, and errno  set.
 *
 * In Windows NT+: fills size, sectors, and cylinders and sets heads to -1.
 * In Windows XP+: fills size, sectors, cylinders, and heads.
 *
 * Note: In pre XP, this requires write permission, even though nothing is
 * actually written.
 *
 * If fails, sets sectors, cylinders, heads, and size to -1.
 */
static int ntfs_device_win32_getgeo(HANDLE handle, win32_fd *fd)
{
        DWORD i;
        BOOL rvl;
        BYTE b[sizeof(DISK_GEOMETRY) + sizeof(DISK_PARTITION_INFO) +
                        sizeof(DISK_DETECTION_INFO) + 512];

        rvl = DeviceIoControl(handle, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX, NULL,
                        0, &b, sizeof(b), &i, NULL);
        if (rvl) {
                ntfs_log_debug("GET_DRIVE_GEOMETRY_EX detected.\n");
                DISK_DETECTION_INFO *ddi = (PDISK_DETECTION_INFO)
                                (((PBYTE)(&((PDISK_GEOMETRY_EX)b)->Data)) +
                                (((PDISK_PARTITION_INFO)
                                (&((PDISK_GEOMETRY_EX)b)->Data))->
                                SizeOfPartitionInfo));
                fd->geo_cylinders = ((DISK_GEOMETRY*)&b)->Cylinders.QuadPart;
                fd->geo_sectors = ((DISK_GEOMETRY*)&b)->SectorsPerTrack;
                fd->geo_size = ((DISK_GEOMETRY_EX*)&b)->DiskSize.QuadPart;
                switch (ddi->DetectionType) {
                case DetectInt13:
                        fd->geo_cylinders = ddi->Int13.MaxCylinders;
                        fd->geo_sectors = ddi->Int13.SectorsPerTrack;
                        fd->geo_heads = ddi->Int13.MaxHeads;
                        return 0;
                case DetectExInt13:
                        fd->geo_cylinders = ddi->ExInt13.ExCylinders;
                        fd->geo_sectors = ddi->ExInt13.ExSectorsPerTrack;
                        fd->geo_heads = ddi->ExInt13.ExHeads;
                        return 0;
                case DetectNone:
                default:
                        break;
                }
        } else
                fd->geo_heads = -1;
        rvl = DeviceIoControl(handle, IOCTL_DISK_GET_DRIVE_GEOMETRY, NULL, 0,
                        &b, sizeof(b), &i, NULL);
        if (rvl) {
                ntfs_log_debug("GET_DRIVE_GEOMETRY detected.\n");
                fd->geo_cylinders = ((DISK_GEOMETRY*)&b)->Cylinders.QuadPart;
                fd->geo_sectors = ((DISK_GEOMETRY*)&b)->SectorsPerTrack;
                fd->geo_size = fd->geo_cylinders * fd->geo_sectors *
                                ((DISK_GEOMETRY*)&b)->TracksPerCylinder *
                                ((DISK_GEOMETRY*)&b)->BytesPerSector;
                return 0;
        }
        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
 *
 * On success returns the number of bytes read (can be < @count) and on error
 * returns -1 and errno set.  Read starts from position @pos.
 *
 * 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 inline s64 ntfs_device_win32_pread_simple(win32_fd *fd, const s64 pos,
                const s64 count, void *b)
{
        return ntfs_device_win32_pio(fd, pos, count, b, FALSE);
}

/**
 * ntfs_device_win32_read - read bytes from an ntfs device
 * @dev:        ntfs device obtained via ->open
 * @b:          pointer to where to put the contents
 * @count:      how many bytes should be read
 *
 * On success returns the number of bytes actually read (can be < @count).
 * On error returns -1 with errno set.
 */
static s64 ntfs_device_win32_read(struct ntfs_device *dev, void *b, s64 count)
{
        s64 old_pos, to_read, i, br = 0;
        win32_fd *fd = (win32_fd *)dev->d_private;
        BYTE *alignedbuffer;
        int old_ofs, ofs;

        old_pos = fd->pos;
        old_ofs = ofs = old_pos & (NTFS_BLOCK_SIZE - 1);
        to_read = (ofs + count + NTFS_BLOCK_SIZE - 1) &
                        ~(s64)(NTFS_BLOCK_SIZE - 1);
        /* Impose maximum of 2GB to be on the safe side. */
        if (to_read > 0x80000000) {
                int delta = to_read - count;
                to_read = 0x80000000;
                count = to_read - delta;
        }
        ntfs_log_trace("fd = %p, b = %p, count = 0x%llx, pos = 0x%llx, "
                        "ofs = %i, to_read = 0x%llx.\n", fd, b,
                        (long long)count, (long long)old_pos, ofs,
                        (long long)to_read);
        if (!((unsigned long)b & (NTFS_BLOCK_SIZE - 1)) && !old_ofs &&
                        !(count & (NTFS_BLOCK_SIZE - 1)))
                alignedbuffer = b;
        else {
                alignedbuffer = (BYTE *)VirtualAlloc(NULL, to_read, MEM_COMMIT,
                                PAGE_READWRITE);
                if (!alignedbuffer) {
                        errno = ntfs_w32error_to_errno(GetLastError());
                        ntfs_log_trace("VirtualAlloc failed for read.\n");
                        return -1;
                }
        }
        if (fd->vol_handle != INVALID_HANDLE_VALUE && old_pos < fd->geo_size) {
                s64 vol_to_read = fd->geo_size - old_pos;
                if (count > vol_to_read) {
                        br = ntfs_device_win32_pread_simple(fd,
                                        old_pos & ~(s64)(NTFS_BLOCK_SIZE - 1),
                                        ofs + vol_to_read, alignedbuffer);
                        if (br == -1)
                                goto read_error;
                        to_read -= br;
                        if (br < ofs) {
                                br = 0;
                                goto read_partial;
                        }
                        br -= ofs;
                        fd->pos += br;
                        ofs = fd->pos & (NTFS_BLOCK_SIZE - 1);
                        if (br != vol_to_read)
                                goto read_partial;
                }
        }
        i = ntfs_device_win32_pread_simple(fd,
                        fd->pos & ~(s64)(NTFS_BLOCK_SIZE - 1), to_read,
                        alignedbuffer + br);
        if (i == -1) {
                if (br)
                        goto read_partial;
                goto read_error;
        }
        if (i < ofs)
                goto read_partial;
        i -= ofs;
        br += i;
        if (br > count)
                br = count;
        fd->pos = old_pos + br;
read_partial:
        if (alignedbuffer != b) {
                memcpy((void*)b, alignedbuffer + old_ofs, br);
                VirtualFree(alignedbuffer, 0, MEM_RELEASE);
        }
        return br;
read_error:
        if (alignedbuffer != b)
                VirtualFree(alignedbuffer, 0, MEM_RELEASE);
        return -1;
}

/**
 * ntfs_device_win32_close - close an open ntfs deivce
 * @dev:        ntfs device obtained via ->open
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.  Note if error fd->vol_handle is trashed.
 */
static int ntfs_device_win32_close(struct ntfs_device *dev)
{
        win32_fd *fd = (win32_fd *)dev->d_private;
        BOOL rvl;

        ntfs_log_trace("Closing device %p.\n", dev);
        if (!NDevOpen(dev)) {
                errno = EBADF;
                return -1;
        }
        if (fd->vol_handle != INVALID_HANDLE_VALUE) {
                if (!NDevReadOnly(dev)) {
                        ntfs_device_win32_dismount(fd->vol_handle);
                        ntfs_device_win32_unlock(fd->vol_handle);
                }
                if (!CloseHandle(fd->vol_handle))
                        ntfs_log_trace("CloseHandle() failed for volume.\n");
        }
        rvl = CloseHandle(fd->handle);
        free(fd);
        if (!rvl) {
                errno = ntfs_w32error_to_errno(GetLastError());
                ntfs_log_trace("CloseHandle() failed.\n");
                return -1;
        }
        return 0;
}

/**
 * ntfs_device_win32_sync - flush write buffers to disk
 * @dev:        ntfs device obtained via ->open
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.
 *
 * Note: Volume syncing works differently in windows.
 *       Disk cannot be synced in windows.
 */
static int ntfs_device_win32_sync(struct ntfs_device *dev)
{
        int err = 0;
        BOOL to_clear = TRUE;

        if (!NDevReadOnly(dev) && NDevDirty(dev)) {
                win32_fd *fd = (win32_fd *)dev->d_private;

                if ((fd->vol_handle != INVALID_HANDLE_VALUE) &&
                                !FlushFileBuffers(fd->vol_handle)) {
                        to_clear = FALSE;
                        err = ntfs_w32error_to_errno(GetLastError());
                }
                if (!FlushFileBuffers(fd->handle)) {
                        to_clear = FALSE;
                        if (!err)
                                err = ntfs_w32error_to_errno(GetLastError());
                }
                if (!to_clear) {
                        ntfs_log_trace("Could not sync.\n");
                        errno = err;
                        return -1;
                }
                NDevClearDirty(dev);
        }
        return 0;
}

/**
 * ntfs_device_win32_pwrite_simple - positioned simple write
 * @fd:         win32 device descriptor obtained via ->open
 * @pos:        at which position to write to
 * @count:      how many bytes should be written
 * @b:          a pointer to the data to write
 *
 * On success returns the number of bytes written and on error returns -1 and
 * errno set.  Write starts from position @pos.
 *
 * 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 inline s64 ntfs_device_win32_pwrite_simple(win32_fd *fd, const s64 pos,
                const s64 count, const void *b)
{
        return ntfs_device_win32_pio(fd, pos, count, (void *)b, TRUE);
}

/**
 * ntfs_device_win32_write - write bytes to an ntfs device
 * @dev:        ntfs device obtained via ->open
 * @b:          pointer to the data to write
 * @count:      how many bytes should be written
 *
 * On success returns the number of bytes actually written.
 * On error returns -1 with errno set.
 */
static s64 ntfs_device_win32_write(struct ntfs_device *dev, const void *b,
                s64 count)
{
        s64 old_pos, to_write, i, bw = 0;
        win32_fd *fd = (win32_fd *)dev->d_private;
        BYTE *alignedbuffer;
        int old_ofs, ofs;

        old_pos = fd->pos;
        old_ofs = ofs = old_pos & (NTFS_BLOCK_SIZE - 1);
        to_write = (ofs + count + NTFS_BLOCK_SIZE - 1) &
                        ~(s64)(NTFS_BLOCK_SIZE - 1);
        /* Impose maximum of 2GB to be on the safe side. */
        if (to_write > 0x80000000) {
                int delta = to_write - count;
                to_write = 0x80000000;
                count = to_write - delta;
        }
        ntfs_log_trace("fd = %p, b = %p, count = 0x%llx, pos = 0x%llx, "
                        "ofs = %i, to_write = 0x%llx.\n", fd, b,
                        (long long)count, (long long)old_pos, ofs,
                        (long long)to_write);
        if (NDevReadOnly(dev)) {
                ntfs_log_trace("Can't write on a R/O device.\n");
                errno = EROFS;
                return -1;
        }
        if (!count)
                return 0;
        NDevSetDirty(dev);
        if (!((unsigned long)b & (NTFS_BLOCK_SIZE - 1)) && !old_ofs &&
                        !(count & (NTFS_BLOCK_SIZE - 1)))
                alignedbuffer = (BYTE *)b;
        else {
                s64 end;

                alignedbuffer = (BYTE *)VirtualAlloc(NULL, to_write,
                                MEM_COMMIT, PAGE_READWRITE);
                if (!alignedbuffer) {
                        errno = ntfs_w32error_to_errno(GetLastError());
                        ntfs_log_trace("VirtualAlloc failed for write.\n");
                        return -1;
                }
                /* Read first sector if start of write not sector aligned. */
                if (ofs) {
                        i = ntfs_device_win32_pread_simple(fd,
                                        old_pos & ~(s64)(NTFS_BLOCK_SIZE - 1),
                                        NTFS_BLOCK_SIZE, alignedbuffer);
                        if (i != NTFS_BLOCK_SIZE) {
                                if (i >= 0)
                                        errno = EIO;
                                goto write_error;
                        }
                }
                /*
                 * Read last sector if end of write not sector aligned and last
                 * sector is either not the same as the first sector or it is
                 * the same as the first sector but this has not been read in
                 * yet, i.e. the start of the write is sector aligned.
                 */
                end = old_pos + count;
                if ((end & (NTFS_BLOCK_SIZE - 1)) &&
                                ((to_write > NTFS_BLOCK_SIZE) || !ofs)) {
                        i = ntfs_device_win32_pread_simple(fd,
                                        end & ~(s64)(NTFS_BLOCK_SIZE - 1),
                                        NTFS_BLOCK_SIZE, alignedbuffer +
                                        to_write - NTFS_BLOCK_SIZE);
                        if (i != NTFS_BLOCK_SIZE) {
                                if (i >= 0)
                                        errno = EIO;
                                goto write_error;
                        }
                }
                /* Copy the data to be written into @alignedbuffer. */
                memcpy(alignedbuffer + ofs, b, count);
        }
        if (fd->vol_handle != INVALID_HANDLE_VALUE && old_pos < fd->geo_size) {
                s64 vol_to_write = fd->geo_size - old_pos;
                if (count > vol_to_write) {
                        bw = ntfs_device_win32_pwrite_simple(fd,
                                        old_pos & ~(s64)(NTFS_BLOCK_SIZE - 1),
                                        ofs + vol_to_write, alignedbuffer);
                        if (bw == -1)
                                goto write_error;
                        to_write -= bw;
                        if (bw < ofs) {
                                bw = 0;
                                goto write_partial;
                        }
                        bw -= ofs;
                        fd->pos += bw;
                        ofs = fd->pos & (NTFS_BLOCK_SIZE - 1);
                        if (bw != vol_to_write)
                                goto write_partial;
                }
        }
        i = ntfs_device_win32_pwrite_simple(fd,
                        fd->pos & ~(s64)(NTFS_BLOCK_SIZE - 1), to_write,
                        alignedbuffer + bw);
        if (i == -1) {
                if (bw)
                        goto write_partial;
                goto write_error;
        }
        if (i < ofs)
                goto write_partial;
        i -= ofs;
        bw += i;
        if (bw > count)
                bw = count;
        fd->pos = old_pos + bw;
write_partial:
        if (alignedbuffer != b)
                VirtualFree(alignedbuffer, 0, MEM_RELEASE);
        return bw;
write_error:
        bw = -1;
        goto write_partial;
}

/**
 * ntfs_device_win32_stat - get a unix-like stat structure for an ntfs device
 * @dev:        ntfs device obtained via ->open
 * @buf:        pointer to the stat structure to fill
 *
 * Note: Only st_mode, st_size, and st_blocks are filled.
 *
 * Return 0 if o.k.
 *       -1 if not and errno set. in this case handle is trashed.
 */
static int ntfs_device_win32_stat(struct ntfs_device *dev, struct stat *buf)
{
        win32_fd *fd = (win32_fd *)dev->d_private;
        mode_t st_mode;

        switch (GetFileType(fd->handle)) {
        case FILE_TYPE_CHAR:
                st_mode = S_IFCHR;
                break;
        case FILE_TYPE_DISK:
                st_mode = S_IFBLK;
                break;
        case FILE_TYPE_PIPE:
                st_mode = S_IFIFO;
                break;
        default:
                st_mode = 0;
        }
        memset(buf, 0, sizeof(struct stat));
        buf->st_mode = st_mode;
        buf->st_size = fd->part_length;
        if (buf->st_size != -1)
                buf->st_blocks = buf->st_size >> 9;
        else
                buf->st_size = 0;
        return 0;
}

/**
 * ntfs_win32_hdio_getgeo - get drive geometry
 * @dev:        ntfs device obtained via ->open
 * @argp:       pointer to where to put the output
 *
 * Note: Works on windows NT/2k/XP only.
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.  Note if error fd->handle is trashed.
 */
static __inline__ int ntfs_win32_hdio_getgeo(struct ntfs_device *dev,
                struct hd_geometry *argp)
{
        win32_fd *fd = (win32_fd *)dev->d_private;

        argp->heads = fd->geo_heads;
        argp->sectors = fd->geo_sectors;
        argp->cylinders = fd->geo_cylinders;
        argp->start = fd->part_hidden_sectors;
        return 0;
}

/**
 * ntfs_win32_blksszget - get block device sector size
 * @dev:        ntfs device obtained via ->open
 * @argp:       pointer to where to put the output
 *
 * Note: Works on windows NT/2k/XP only.
 *
 * Return 0 if o.k.
 *       -1 if not, and errno set.  Note if error fd->handle is trashed.
 */
static __inline__ int ntfs_win32_blksszget(struct ntfs_device *dev,int *argp)
{
        win32_fd *fd = (win32_fd *)dev->d_private;
        DWORD bytesReturned;
        DISK_GEOMETRY dg;

        if (DeviceIoControl(fd->handle, IOCTL_DISK_GET_DRIVE_GEOMETRY, NULL, 0,
                        &dg, sizeof(DISK_GEOMETRY), &bytesReturned, NULL)) {
                /* success */
                *argp = dg.BytesPerSector;
                return 0;
        }
        errno = ntfs_w32error_to_errno(GetLastError());
        ntfs_log_trace("GET_DRIVE_GEOMETRY failed.\n");
        return -1;
}

static int ntfs_device_win32_ioctl(struct ntfs_device *dev, int request,
                void *argp)
{
        win32_fd *fd = (win32_fd *)dev->d_private;

        ntfs_log_trace("win32_ioctl(%d) called.\n", request);
        switch (request) {
#if defined(BLKGETSIZE)
        case BLKGETSIZE:
                ntfs_log_debug("BLKGETSIZE detected.\n");
                if (fd->part_length >= 0) {
                        *(int *)argp = (int)(fd->part_length / 512);
                        return 0;
                }
                errno = EOPNOTSUPP;
                return -1;
#endif
#if defined(BLKGETSIZE64)
        case BLKGETSIZE64:
                ntfs_log_debug("BLKGETSIZE64 detected.\n");
                if (fd->part_length >= 0) {
                        *(s64 *)argp = fd->part_length;
                        return 0;
                }
                errno = EOPNOTSUPP;
                return -1;
#endif
#ifdef HDIO_GETGEO
        case HDIO_GETGEO:
                ntfs_log_debug("HDIO_GETGEO detected.\n");
                return ntfs_win32_hdio_getgeo(dev, (struct hd_geometry *)argp);
#endif
#ifdef BLKSSZGET
        case BLKSSZGET:
                ntfs_log_debug("BLKSSZGET detected.\n");
                return ntfs_win32_blksszget(dev, (int *)argp);
#endif
#ifdef BLKBSZSET
        case BLKBSZSET:
                ntfs_log_debug("BLKBSZSET detected.\n");
                /* Nothing to do on Windows. */
                return 0;
#endif
        default:
                ntfs_log_debug("unimplemented ioctl %d.\n", request);
                errno = EOPNOTSUPP;
                return -1;
        }
}

static s64 ntfs_device_win32_pread(struct ntfs_device *dev, void *b,
                s64 count, s64 offset)
{
        return ntfs_pread(dev, offset, count, b);
}

static s64 ntfs_device_win32_pwrite(struct ntfs_device *dev, const void *b,
                s64 count, s64 offset)
{
        return ntfs_pwrite(dev, offset, count, b);
}

struct ntfs_device_operations ntfs_device_win32_io_ops = {
        .open           = ntfs_device_win32_open,
        .close          = ntfs_device_win32_close,
        .seek           = ntfs_device_win32_seek,
        .read           = ntfs_device_win32_read,
        .write          = ntfs_device_win32_write,
        .pread          = ntfs_device_win32_pread,
        .pwrite         = ntfs_device_win32_pwrite,
        .sync           = ntfs_device_win32_sync,
        .stat           = ntfs_device_win32_stat,
        .ioctl          = ntfs_device_win32_ioctl
};