block/raw-win32.c - qemu - Git at Google

 /*
  * Block driver for RAW files (win32)
  *
  * Copyright (c) 2006 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 #include "qemu-common.h"
 #include "qemu-timer.h"
 #include "block_int.h"
 #include "module.h"
 #include <windows.h>
 #include <winioctl.h>

 #define FTYPE_FILE 0
 #define FTYPE_CD     1
 #define FTYPE_HARDDISK 2

 typedef struct BDRVRawState {
     HANDLE hfile;
     int type;
     char drive_path[16]; /* format: "d:\" */
 } BDRVRawState;

 int qemu_ftruncate64(int fd, int64_t length)
 {
     LARGE_INTEGER li;
     DWORD dw;
     LONG high;
     HANDLE h;
     BOOL res;

     if ((GetVersion() & 0x80000000UL) && (length >> 32) != 0)
 	return -1;

     h = (HANDLE)_get_osfhandle(fd);

     /* get current position, ftruncate do not change position */
     li.HighPart = 0;
     li.LowPart = SetFilePointer (h, 0, &li.HighPart, FILE_CURRENT);
     if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
 	return -1;
     }

     high = length >> 32;
     dw = SetFilePointer(h, (DWORD) length, &high, FILE_BEGIN);
     if (dw == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
 	return -1;
     }
     res = SetEndOfFile(h);

     /* back to old position */
     SetFilePointer(h, li.LowPart, &li.HighPart, FILE_BEGIN);
     return res ? 0 : -1;
 }

 static int set_sparse(int fd)
 {
     DWORD returned;
     return (int) DeviceIoControl((HANDLE)_get_osfhandle(fd), FSCTL_SET_SPARSE,
 				 NULL, 0, NULL, 0, &returned, NULL);
 }

 static int raw_open(BlockDriverState *bs, const char *filename, int flags)
 {
     BDRVRawState *s = bs->opaque;
     int access_flags;
     DWORD overlapped;

     s->type = FTYPE_FILE;

     if (flags & BDRV_O_RDWR) {
         access_flags = GENERIC_READ | GENERIC_WRITE;
     } else {
         access_flags = GENERIC_READ;
     }

     overlapped = FILE_ATTRIBUTE_NORMAL;
     if (flags & BDRV_O_NOCACHE)
         overlapped |= FILE_FLAG_NO_BUFFERING;
     if (!(flags & BDRV_O_CACHE_WB))
         overlapped |= FILE_FLAG_WRITE_THROUGH;
     s->hfile = CreateFile(filename, access_flags,
                           FILE_SHARE_READ, NULL,
                           OPEN_EXISTING, overlapped, NULL);
     if (s->hfile == INVALID_HANDLE_VALUE) {
         int err = GetLastError();

         if (err == ERROR_ACCESS_DENIED)
             return -EACCES;
         return -1;
     }
     return 0;
 }

 static int raw_read(BlockDriverState *bs, int64_t sector_num,
                     uint8_t *buf, int nb_sectors)
 {
     BDRVRawState *s = bs->opaque;
     OVERLAPPED ov;
     DWORD ret_count;
     int ret;
     int64_t offset = sector_num * 512;
     int count = nb_sectors * 512;

     memset(&ov, 0, sizeof(ov));
     ov.Offset = offset;
     ov.OffsetHigh = offset >> 32;
     ret = ReadFile(s->hfile, buf, count, &ret_count, &ov);
     if (!ret)
         return ret_count;
     if (ret_count == count)
         ret_count = 0;
     return ret_count;
 }

 static int raw_write(BlockDriverState *bs, int64_t sector_num,
                      const uint8_t *buf, int nb_sectors)
 {
     BDRVRawState *s = bs->opaque;
     OVERLAPPED ov;
     DWORD ret_count;
     int ret;
     int64_t offset = sector_num * 512;
     int count = nb_sectors * 512;

     memset(&ov, 0, sizeof(ov));
     ov.Offset = offset;
     ov.OffsetHigh = offset >> 32;
     ret = WriteFile(s->hfile, buf, count, &ret_count, &ov);
     if (!ret)
         return ret_count;
     if (ret_count == count)
         ret_count = 0;
     return ret_count;
 }

 static int raw_flush(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     int ret;

     ret = FlushFileBuffers(s->hfile);
     if (ret == 0) {
         return -EIO;
     }

     return 0;
 }

 static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     CloseHandle(s->hfile);
 }

 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 {
     BDRVRawState *s = bs->opaque;
     LONG low, high;

     low = offset;
     high = offset >> 32;
     if (!SetFilePointer(s->hfile, low, &high, FILE_BEGIN))
 	return -EIO;
     if (!SetEndOfFile(s->hfile))
         return -EIO;
     return 0;
 }

 static int64_t raw_getlength(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     LARGE_INTEGER l;
     ULARGE_INTEGER available, total, total_free;
     DISK_GEOMETRY_EX dg;
     DWORD count;
     BOOL status;

     switch(s->type) {
     case FTYPE_FILE:
         l.LowPart = GetFileSize(s->hfile, (PDWORD)&l.HighPart);
         if (l.LowPart == 0xffffffffUL && GetLastError() != NO_ERROR)
             return -EIO;
         break;
     case FTYPE_CD:
         if (!GetDiskFreeSpaceEx(s->drive_path, &available, &total, &total_free))
             return -EIO;
         l.QuadPart = total.QuadPart;
         break;
     case FTYPE_HARDDISK:
         status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
                                  NULL, 0, &dg, sizeof(dg), &count, NULL);
         if (status != 0) {
             l = dg.DiskSize;
         }
         break;
     default:
         return -EIO;
     }
     return l.QuadPart;
 }

 static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
 {
     typedef DWORD (WINAPI * get_compressed_t)(const char *filename,
                                               DWORD * high);
     get_compressed_t get_compressed;
     struct _stati64 st;
     const char *filename = bs->filename;
     /* WinNT support GetCompressedFileSize to determine allocate size */
     get_compressed =
         (get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"),
                                             "GetCompressedFileSizeA");
     if (get_compressed) {
         DWORD high, low;
         low = get_compressed(filename, &high);
         if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR) {
             return (((int64_t) high) << 32) + low;
         }
     }

     if (_stati64(filename, &st) < 0) {
         return -1;
     }
     return st.st_size;
 }

 static int raw_create(const char *filename, QEMUOptionParameter *options)
 {
     int fd;
     int64_t total_size = 0;

     /* Read out options */
     while (options && options->name) {
         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
             total_size = options->value.n / 512;
         }
         options++;
     }

     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
               0644);
     if (fd < 0)
         return -EIO;
     set_sparse(fd);
     ftruncate(fd, total_size * 512);
     close(fd);
     return 0;
 }

 static QEMUOptionParameter raw_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
         .type = OPT_SIZE,
         .help = "Virtual disk size"
     },
     { NULL }
 };

 static BlockDriver bdrv_file = {
     .format_name	= "file",
     .protocol_name	= "file",
     .instance_size	= sizeof(BDRVRawState),
     .bdrv_file_open	= raw_open,
     .bdrv_close		= raw_close,
     .bdrv_create	= raw_create,
     .bdrv_flush		= raw_flush,
     .bdrv_read		= raw_read,
     .bdrv_write		= raw_write,
     .bdrv_truncate	= raw_truncate,
     .bdrv_getlength	= raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,

     .create_options = raw_create_options,
 };

 /***********************************************/
 /* host device */

 static int find_cdrom(char *cdrom_name, int cdrom_name_size)
 {
     char drives[256], *pdrv = drives;
     UINT type;

     memset(drives, 0, sizeof(drives));
     GetLogicalDriveStrings(sizeof(drives), drives);
     while(pdrv[0] != '\0') {
         type = GetDriveType(pdrv);
         switch(type) {
         case DRIVE_CDROM:
             snprintf(cdrom_name, cdrom_name_size, "\\\\.\\%c:", pdrv[0]);
             return 0;
             break;
         }
         pdrv += lstrlen(pdrv) + 1;
     }
     return -1;
 }

 static int find_device_type(BlockDriverState *bs, const char *filename)
 {
     BDRVRawState *s = bs->opaque;
     UINT type;
     const char *p;

     if (strstart(filename, "\\\\.\\", &p) ||
         strstart(filename, "//./", &p)) {
         if (stristart(p, "PhysicalDrive", NULL))
             return FTYPE_HARDDISK;
         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", p[0]);
         type = GetDriveType(s->drive_path);
         switch (type) {
         case DRIVE_REMOVABLE:
         case DRIVE_FIXED:
             return FTYPE_HARDDISK;
         case DRIVE_CDROM:
             return FTYPE_CD;
         default:
             return FTYPE_FILE;
         }
     } else {
         return FTYPE_FILE;
     }
 }

 static int hdev_probe_device(const char *filename)
 {
     if (strstart(filename, "/dev/cdrom", NULL))
         return 100;
     if (is_windows_drive(filename))
         return 100;
     return 0;
 }

 static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
 {
     BDRVRawState *s = bs->opaque;
     int access_flags, create_flags;
     DWORD overlapped;
     char device_name[64];

     if (strstart(filename, "/dev/cdrom", NULL)) {
         if (find_cdrom(device_name, sizeof(device_name)) < 0)
             return -ENOENT;
         filename = device_name;
     } else {
         /* transform drive letters into device name */
         if (((filename[0] >= 'a' && filename[0] <= 'z') ||
              (filename[0] >= 'A' && filename[0] <= 'Z')) &&
             filename[1] == ':' && filename[2] == '\0') {
             snprintf(device_name, sizeof(device_name), "\\\\.\\%c:", filename[0]);
             filename = device_name;
         }
     }
     s->type = find_device_type(bs, filename);

     if (flags & BDRV_O_RDWR) {
         access_flags = GENERIC_READ | GENERIC_WRITE;
     } else {
         access_flags = GENERIC_READ;
     }
     create_flags = OPEN_EXISTING;

     overlapped = FILE_ATTRIBUTE_NORMAL;
     if (flags & BDRV_O_NOCACHE)
         overlapped |= FILE_FLAG_NO_BUFFERING;
     if (!(flags & BDRV_O_CACHE_WB))
         overlapped |= FILE_FLAG_WRITE_THROUGH;
     s->hfile = CreateFile(filename, access_flags,
                           FILE_SHARE_READ, NULL,
                           create_flags, overlapped, NULL);
     if (s->hfile == INVALID_HANDLE_VALUE) {
         int err = GetLastError();

         if (err == ERROR_ACCESS_DENIED)
             return -EACCES;
         return -1;
     }
     return 0;
 }

 static int hdev_has_zero_init(BlockDriverState *bs)
 {
     return 0;
 }

 static BlockDriver bdrv_host_device = {
     .format_name	= "host_device",
     .protocol_name	= "host_device",
     .instance_size	= sizeof(BDRVRawState),
     .bdrv_probe_device	= hdev_probe_device,
     .bdrv_file_open	= hdev_open,
     .bdrv_close		= raw_close,
     .bdrv_flush		= raw_flush,
     .bdrv_has_zero_init = hdev_has_zero_init,

     .bdrv_read		= raw_read,
     .bdrv_write	        = raw_write,
     .bdrv_getlength	= raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,
 };

 static void bdrv_file_init(void)
 {
     bdrv_register(&bdrv_file);
     bdrv_register(&bdrv_host_device);
 }

 block_init(bdrv_file_init);
	/*
	* Block driver for RAW files (win32)
	*
	* Copyright (c) 2006 Fabrice Bellard
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/
	#include "qemu-common.h"
	#include "qemu-timer.h"
	#include "block_int.h"
	#include "module.h"
	#include <windows.h>
	#include <winioctl.h>

	#define FTYPE_FILE 0
	#define FTYPE_CD 1
	#define FTYPE_HARDDISK 2

	typedef struct BDRVRawState {
	HANDLE hfile;
	int type;
	char drive_path[16]; /* format: "d:\" */
	} BDRVRawState;

	int qemu_ftruncate64(int fd, int64_t length)
	{
	LARGE_INTEGER li;
	DWORD dw;
	LONG high;
	HANDLE h;
	BOOL res;

	if ((GetVersion() & 0x80000000UL) && (length >> 32) != 0)
	return -1;

	h = (HANDLE)_get_osfhandle(fd);

	/* get current position, ftruncate do not change position */
	li.HighPart = 0;
	li.LowPart = SetFilePointer (h, 0, &li.HighPart, FILE_CURRENT);
	if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
	return -1;
	}

	high = length >> 32;
	dw = SetFilePointer(h, (DWORD) length, &high, FILE_BEGIN);
	if (dw == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
	return -1;
	}
	res = SetEndOfFile(h);

	/* back to old position */
	SetFilePointer(h, li.LowPart, &li.HighPart, FILE_BEGIN);
	return res ? 0 : -1;
	}

	static int set_sparse(int fd)
	{
	DWORD returned;
	return (int) DeviceIoControl((HANDLE)_get_osfhandle(fd), FSCTL_SET_SPARSE,
	NULL, 0, NULL, 0, &returned, NULL);
	}

	static int raw_open(BlockDriverState bs, const char filename, int flags)
	{
	BDRVRawState *s = bs->opaque;
	int access_flags;
	DWORD overlapped;

	s->type = FTYPE_FILE;

	if (flags & BDRV_O_RDWR) {
	access_flags = GENERIC_READ \| GENERIC_WRITE;
	} else {
	access_flags = GENERIC_READ;
	}

	overlapped = FILE_ATTRIBUTE_NORMAL;
	if (flags & BDRV_O_NOCACHE)
	overlapped \|= FILE_FLAG_NO_BUFFERING;
	if (!(flags & BDRV_O_CACHE_WB))
	overlapped \|= FILE_FLAG_WRITE_THROUGH;
	s->hfile = CreateFile(filename, access_flags,
	FILE_SHARE_READ, NULL,
	OPEN_EXISTING, overlapped, NULL);
	if (s->hfile == INVALID_HANDLE_VALUE) {
	int err = GetLastError();

	if (err == ERROR_ACCESS_DENIED)
	return -EACCES;
	return -1;
	}
	return 0;
	}

	static int raw_read(BlockDriverState *bs, int64_t sector_num,
	uint8_t *buf, int nb_sectors)
	{
	BDRVRawState *s = bs->opaque;
	OVERLAPPED ov;
	DWORD ret_count;
	int ret;
	int64_t offset = sector_num * 512;
	int count = nb_sectors * 512;

	memset(&ov, 0, sizeof(ov));
	ov.Offset = offset;
	ov.OffsetHigh = offset >> 32;
	ret = ReadFile(s->hfile, buf, count, &ret_count, &ov);
	if (!ret)
	return ret_count;
	if (ret_count == count)
	ret_count = 0;
	return ret_count;
	}

	static int raw_write(BlockDriverState *bs, int64_t sector_num,
	const uint8_t *buf, int nb_sectors)
	{
	BDRVRawState *s = bs->opaque;
	OVERLAPPED ov;
	DWORD ret_count;
	int ret;
	int64_t offset = sector_num * 512;
	int count = nb_sectors * 512;

	memset(&ov, 0, sizeof(ov));
	ov.Offset = offset;
	ov.OffsetHigh = offset >> 32;
	ret = WriteFile(s->hfile, buf, count, &ret_count, &ov);
	if (!ret)
	return ret_count;
	if (ret_count == count)
	ret_count = 0;
	return ret_count;
	}

	static int raw_flush(BlockDriverState *bs)
	{
	BDRVRawState *s = bs->opaque;
	int ret;

	ret = FlushFileBuffers(s->hfile);
	if (ret == 0) {
	return -EIO;
	}

	return 0;
	}

	static void raw_close(BlockDriverState *bs)
	{
	BDRVRawState *s = bs->opaque;
	CloseHandle(s->hfile);
	}

	static int raw_truncate(BlockDriverState *bs, int64_t offset)
	{
	BDRVRawState *s = bs->opaque;
	LONG low, high;

	low = offset;
	high = offset >> 32;
	if (!SetFilePointer(s->hfile, low, &high, FILE_BEGIN))
	return -EIO;
	if (!SetEndOfFile(s->hfile))
	return -EIO;
	return 0;
	}

	static int64_t raw_getlength(BlockDriverState *bs)
	{
	BDRVRawState *s = bs->opaque;
	LARGE_INTEGER l;
	ULARGE_INTEGER available, total, total_free;
	DISK_GEOMETRY_EX dg;
	DWORD count;
	BOOL status;

	switch(s->type) {
	case FTYPE_FILE:
	l.LowPart = GetFileSize(s->hfile, (PDWORD)&l.HighPart);
	if (l.LowPart == 0xffffffffUL && GetLastError() != NO_ERROR)
	return -EIO;
	break;
	case FTYPE_CD:
	if (!GetDiskFreeSpaceEx(s->drive_path, &available, &total, &total_free))
	return -EIO;
	l.QuadPart = total.QuadPart;
	break;
	case FTYPE_HARDDISK:
	status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
	NULL, 0, &dg, sizeof(dg), &count, NULL);
	if (status != 0) {
	l = dg.DiskSize;
	}
	break;
	default:
	return -EIO;
	}
	return l.QuadPart;
	}

	static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
	{
	typedef DWORD (WINAPI * get_compressed_t)(const char *filename,
	DWORD * high);
	get_compressed_t get_compressed;
	struct _stati64 st;
	const char *filename = bs->filename;
	/* WinNT support GetCompressedFileSize to determine allocate size */
	get_compressed =
	(get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"),
	"GetCompressedFileSizeA");
	if (get_compressed) {
	DWORD high, low;
	low = get_compressed(filename, &high);
	if (low != 0xFFFFFFFFlu \|\| GetLastError() == NO_ERROR) {
	return (((int64_t) high) << 32) + low;
	}
	}

	if (_stati64(filename, &st) < 0) {
	return -1;
	}
	return st.st_size;
	}

	static int raw_create(const char filename, QEMUOptionParameter options)
	{
	int fd;
	int64_t total_size = 0;

	/* Read out options */
	while (options && options->name) {
	if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
	total_size = options->value.n / 512;
	}
	options++;
	}

	fd = open(filename, O_WRONLY \| O_CREAT \| O_TRUNC \| O_BINARY,
	0644);
	if (fd < 0)
	return -EIO;
	set_sparse(fd);
	ftruncate(fd, total_size * 512);
	close(fd);
	return 0;
	}

	static QEMUOptionParameter raw_create_options[] = {
	{
	.name = BLOCK_OPT_SIZE,
	.type = OPT_SIZE,
	.help = "Virtual disk size"
	},
	{ NULL }
	};

	static BlockDriver bdrv_file = {
	.format_name = "file",
	.protocol_name = "file",
	.instance_size = sizeof(BDRVRawState),
	.bdrv_file_open = raw_open,
	.bdrv_close = raw_close,
	.bdrv_create = raw_create,
	.bdrv_flush = raw_flush,
	.bdrv_read = raw_read,
	.bdrv_write = raw_write,
	.bdrv_truncate = raw_truncate,
	.bdrv_getlength = raw_getlength,
	.bdrv_get_allocated_file_size
	= raw_get_allocated_file_size,

	.create_options = raw_create_options,
	};

	/***********************************************/
	/* host device */

	static int find_cdrom(char *cdrom_name, int cdrom_name_size)
	{
	char drives[256], *pdrv = drives;
	UINT type;

	memset(drives, 0, sizeof(drives));
	GetLogicalDriveStrings(sizeof(drives), drives);
	while(pdrv[0] != '\0') {
	type = GetDriveType(pdrv);
	switch(type) {
	case DRIVE_CDROM:
	snprintf(cdrom_name, cdrom_name_size, "\\\\.\\%c:", pdrv[0]);
	return 0;
	break;
	}
	pdrv += lstrlen(pdrv) + 1;
	}
	return -1;
	}

	static int find_device_type(BlockDriverState bs, const char filename)
	{
	BDRVRawState *s = bs->opaque;
	UINT type;
	const char *p;

	if (strstart(filename, "\\\\.\\", &p) \|\|
	strstart(filename, "//./", &p)) {
	if (stristart(p, "PhysicalDrive", NULL))
	return FTYPE_HARDDISK;
	snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", p[0]);
	type = GetDriveType(s->drive_path);
	switch (type) {
	case DRIVE_REMOVABLE:
	case DRIVE_FIXED:
	return FTYPE_HARDDISK;
	case DRIVE_CDROM:
	return FTYPE_CD;
	default:
	return FTYPE_FILE;
	}
	} else {
	return FTYPE_FILE;
	}
	}

	static int hdev_probe_device(const char *filename)
	{
	if (strstart(filename, "/dev/cdrom", NULL))
	return 100;
	if (is_windows_drive(filename))
	return 100;
	return 0;
	}

	static int hdev_open(BlockDriverState bs, const char filename, int flags)
	{
	BDRVRawState *s = bs->opaque;
	int access_flags, create_flags;
	DWORD overlapped;
	char device_name[64];

	if (strstart(filename, "/dev/cdrom", NULL)) {
	if (find_cdrom(device_name, sizeof(device_name)) < 0)
	return -ENOENT;
	filename = device_name;
	} else {
	/* transform drive letters into device name */
	if (((filename[0] >= 'a' && filename[0] <= 'z') \|\|
	(filename[0] >= 'A' && filename[0] <= 'Z')) &&
	filename[1] == ':' && filename[2] == '\0') {
	snprintf(device_name, sizeof(device_name), "\\\\.\\%c:", filename[0]);
	filename = device_name;
	}
	}
	s->type = find_device_type(bs, filename);

	if (flags & BDRV_O_RDWR) {
	access_flags = GENERIC_READ \| GENERIC_WRITE;
	} else {
	access_flags = GENERIC_READ;
	}
	create_flags = OPEN_EXISTING;

	overlapped = FILE_ATTRIBUTE_NORMAL;
	if (flags & BDRV_O_NOCACHE)
	overlapped \|= FILE_FLAG_NO_BUFFERING;
	if (!(flags & BDRV_O_CACHE_WB))
	overlapped \|= FILE_FLAG_WRITE_THROUGH;
	s->hfile = CreateFile(filename, access_flags,
	FILE_SHARE_READ, NULL,
	create_flags, overlapped, NULL);
	if (s->hfile == INVALID_HANDLE_VALUE) {
	int err = GetLastError();

	if (err == ERROR_ACCESS_DENIED)
	return -EACCES;
	return -1;
	}
	return 0;
	}

	static int hdev_has_zero_init(BlockDriverState *bs)
	{
	return 0;
	}

	static BlockDriver bdrv_host_device = {
	.format_name = "host_device",
	.protocol_name = "host_device",
	.instance_size = sizeof(BDRVRawState),
	.bdrv_probe_device = hdev_probe_device,
	.bdrv_file_open = hdev_open,
	.bdrv_close = raw_close,
	.bdrv_flush = raw_flush,
	.bdrv_has_zero_init = hdev_has_zero_init,

	.bdrv_read = raw_read,
	.bdrv_write = raw_write,
	.bdrv_getlength = raw_getlength,
	.bdrv_get_allocated_file_size
	= raw_get_allocated_file_size,
	};

	static void bdrv_file_init(void)
	{
	bdrv_register(&bdrv_file);
	bdrv_register(&bdrv_host_device);
	}

	block_init(bdrv_file_init);