/*
 * Copyright (C) 2011 Andrea Mazzoleni
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "portable.h"

#include "util.h"

#ifdef __MINGW32__ /* Only for MingW */

/**
 * Standard exit codes.
 */
int exit_success = 0;
int exit_failure = 1;

/* Adds missing Windows declaration */
typedef struct _FILE_ATTRIBUTE_TAG_INFO {
	DWORD FileAttributes;
	DWORD ReparseTag;
} FILE_ATTRIBUTE_TAG_INFO;

typedef struct _FILE_ID_BOTH_DIR_INFO {
	DWORD NextEntryOffset;
	DWORD FileIndex;
	LARGE_INTEGER CreationTime;
	LARGE_INTEGER LastAccessTime;
	LARGE_INTEGER LastWriteTime;
	LARGE_INTEGER ChangeTime;
	LARGE_INTEGER EndOfFile;
	LARGE_INTEGER AllocationSize;
	DWORD FileAttributes;
	DWORD FileNameLength;
	DWORD EaSize;
	CCHAR ShortNameLength;
	WCHAR ShortName[12];
	LARGE_INTEGER FileId;
	WCHAR FileName[1];
} FILE_ID_BOTH_DIR_INFO;

#define FileAttributeTagInfo 9
#define FileIdBothDirectoryInfo 10

#ifndef IO_REPARSE_TAG_DEDUP
#define IO_REPARSE_TAG_DEDUP (0x80000013)
#endif
#ifndef IO_REPARSE_TAG_NFS
#define IO_REPARSE_TAG_NFS (0x80000014)
#endif
#ifndef IO_REPARSE_TAG_MOUNT_POINT
#define IO_REPARSE_TAG_MOUNT_POINT (0xA0000003)
#endif
#ifndef IO_REPARSE_TAG_SYMLINK
#define IO_REPARSE_TAG_SYMLINK (0xA000000C)
#endif

/* For SetThreadExecutionState */
#define WIN32_ES_SYSTEM_REQUIRED      0x00000001L
#define WIN32_ES_DISPLAY_REQUIRED     0x00000002L
#define WIN32_ES_USER_PRESENT         0x00000004L
#define WIN32_ES_AWAYMODE_REQUIRED    0x00000040L
#define WIN32_ES_CONTINUOUS           0x80000000L

#ifndef FSCTL_GET_RETRIEVAL_POINTERS
#define FSCTL_GET_RETRIEVAL_POINTERS 0x00090073

typedef struct RETRIEVAL_POINTERS_BUFFER {
	DWORD ExtentCount;
	LARGE_INTEGER StartingVcn;
	struct {
		LARGE_INTEGER NextVcn;
		LARGE_INTEGER Lcn;
	} Extents[1];
} RETRIEVAL_POINTERS_BUFFER;

typedef struct {
	LARGE_INTEGER StartingVcn;
} STARTING_VCN_INPUT_BUFFER;
#endif

/**
 * Portable implementation of GetFileInformationByHandleEx.
 * This function is not available in Windows XP.
 */
static BOOL (WINAPI* ptr_GetFileInformationByHandleEx)(HANDLE, DWORD, LPVOID, DWORD);

/**
 * Portable implementation of CreateSymbolicLinkW.
 * This function is not available in Windows XP.
 */
static BOOLEAN (WINAPI* ptr_CreateSymbolicLinkW)(LPWSTR, LPWSTR, DWORD);

/**
 * Direct access to RtlGenRandom().
 * This function is accessible only with LoadLibrary() and it's availble from Windows XP.
 */
static BOOLEAN (WINAPI* ptr_RtlGenRandom)(PVOID, ULONG);

/**
 * Description of the last error.
 */
static char* last_error;

/**
 * If we are running in Wine.
 */
static int is_wine;

/**
 * If we should use the legacy FindFirst/Next way to list directories.
 */
static int is_scan_winfind;

/**
 * Loaded ADVAPI32.DLL.
 */
static HMODULE dll_advapi32;

void os_init(int opt)
{
	HMODULE ntdll, kernel32;

	is_scan_winfind = opt != 0;

	ntdll = GetModuleHandle("NTDLL.DLL");
	if (!ntdll) {
		fprintf(stderr, "Error loading the NTDLL module.\n");
		exit(EXIT_FAILURE);
	}

	kernel32 = GetModuleHandle("KERNEL32.DLL");
	if (!kernel32) {
		fprintf(stderr, "Error loading the KERNEL32 module.\n");
		exit(EXIT_FAILURE);
	}

	dll_advapi32 = LoadLibrary("ADVAPI32.DLL");
	if (!dll_advapi32) {
		fprintf(stderr, "Error loading the ADVAPI32 module.\n");
		exit(EXIT_FAILURE);
	}

	/* check for Wine presence */
	is_wine = GetProcAddress(ntdll, "wine_get_version") != 0;

	/* load functions not always available */
	ptr_GetFileInformationByHandleEx = (void*)GetProcAddress(kernel32, "GetFileInformationByHandleEx");
	ptr_CreateSymbolicLinkW = (void*)GetProcAddress(kernel32, "CreateSymbolicLinkW");

	ptr_RtlGenRandom = (void*)GetProcAddress(dll_advapi32, "SystemFunction036");
	if (!ptr_RtlGenRandom) {
		fprintf(stderr, "Error loading RtlGenRandom() from the ADVAPI32 module.\n");
		exit(EXIT_FAILURE);
	}

	/* set the thread execution level to avoid sleep */
	/* first try for Windows 7 */
	if (SetThreadExecutionState(WIN32_ES_CONTINUOUS | WIN32_ES_SYSTEM_REQUIRED | WIN32_ES_AWAYMODE_REQUIRED) == 0) {
		/* retry with the XP variant */
		SetThreadExecutionState(WIN32_ES_CONTINUOUS | WIN32_ES_SYSTEM_REQUIRED);
	}

	last_error = 0;
}

void os_done(void)
{
	free(last_error);

	/* restore the normal execution level */
	SetThreadExecutionState(WIN32_ES_CONTINUOUS);

	FreeLibrary(dll_advapi32);
}

/**
 * Number of conversion buffers.
 */
#define CONV_ROLL 4

/**
 * Buffers for UTF16.
 */
static unsigned conv_utf16 = 0;
static wchar_t conv_utf16_buffer[CONV_ROLL][PATH_MAX];

/**
 * Buffers for UTF8.
 */
static unsigned conv_utf8 = 0;
static char conv_utf8_buffer[CONV_ROLL][PATH_MAX];

/**
 * Converts a generic string from UTF8 to UTF16.
 */
static wchar_t* u8tou16(const char* src)
{
	int ret;

	if (++conv_utf16 == CONV_ROLL)
		conv_utf16 = 0;

	ret = MultiByteToWideChar(CP_UTF8, 0, src, -1, conv_utf16_buffer[conv_utf16], sizeof(conv_utf16_buffer[0]) / sizeof(wchar_t));

	if (ret <= 0) {
		fprintf(stderr, "Error converting name '%s' from UTF-8 to UTF-16\n", src);
		exit(EXIT_FAILURE);
	}

	return conv_utf16_buffer[conv_utf16];
}

/**
 * Converts a generic string from UTF16 to UTF8.
 */
static char* u16tou8(const wchar_t* src, size_t number_of_wchar, size_t* result_length_without_terminator)
{
	int ret;

	if (++conv_utf8 == CONV_ROLL)
		conv_utf8 = 0;

	ret = WideCharToMultiByte(CP_UTF8, 0, src, number_of_wchar, conv_utf8_buffer[conv_utf8], sizeof(conv_utf8_buffer[0]), 0, 0);
	if (ret <= 0) {
		fprintf(stderr, "Error converting from UTF-16 to UTF-8\n");
		exit(EXIT_FAILURE);
	}

	*result_length_without_terminator = ret;

	return conv_utf8_buffer[conv_utf8];
}

/**
 * Check if the char is a forward or back slash.
 */
static int is_slash(char c)
{
	return c == '/' || c == '\\';
}

/**
 * Converts a path to the Windows format.
 *
 * If only_is_required is 1, the extended-length format is used only if required.
 *
 * The exact operation done is:
 * - If it's a '\\?\' path, convert any '/' to '\'.
 * - If it's a disk designator path, like 'D:\' or 'D:/', it prepends '\\?\' to the path and convert any '/' to '\'.
 * - If it's a UNC path, like ''\\server'', it prepends '\\?\UNC\' to the path and convert any '/' to '\'.
 * - Otherwise, only the UTF conversion is done. In this case Windows imposes a limit of 260 chars, and automatically convert any '/' to '\'.
 *
 * For more details see:
 * Naming Files, Paths, and Namespaces
 * http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx#maxpath
 */
static wchar_t* convert_arg(const char* src, int only_if_required)
{
	int ret;
	wchar_t* dst;
	int count;

	if (++conv_utf16 == CONV_ROLL)
		conv_utf16 = 0;

	dst = conv_utf16_buffer[conv_utf16];

	/* note that we always check for both / and \ because the path is blindly */
	/* converted to unix format by path_import() */

	if (only_if_required && strlen(src) < 260 - 12) {
		/* it's a short path */
		/* 260 is the MAX_PATH, note that it includes the space for the terminating NUL */
		/* 12 is an additional space for filename, required when creating directory */

		/* do nothing */
	} else if (is_slash(src[0]) && is_slash(src[1]) && src[2] == '?' && is_slash(src[3])) {
		/* if it's already a '\\?\' path */

		/* do nothing */
	} else if (is_slash(src[0]) && is_slash(src[1])) {
		/* if it is a UNC path, like '\\server' */

		/* prefix with '\\?\UNC\' */
		*dst++ = L'\\';
		*dst++ = L'\\';
		*dst++ = L'?';
		*dst++ = L'\\';
		*dst++ = L'U';
		*dst++ = L'N';
		*dst++ = L'C';
		*dst++ = L'\\';

		/* skip initial '\\' */
		src += 2;
	} else if (src[0] != 0 && src[1] == ':' && is_slash(src[2])) {
		/* if it is a disk designator path, like 'D:\' or 'D:/' */

		/* prefix with '\\?\' */
		*dst++ = L'\\';
		*dst++ = L'\\';
		*dst++ = L'?';
		*dst++ = L'\\';
	}

	/* chars already used */
	count = dst - conv_utf16_buffer[conv_utf16];

	ret = MultiByteToWideChar(CP_UTF8, 0, src, -1, dst, sizeof(conv_utf16_buffer[0]) / sizeof(wchar_t) - count);

	if (ret <= 0) {
		fprintf(stderr, "Error converting name '%s' from UTF-8 to UTF-16\n", src);
		exit(EXIT_FAILURE);
	}

	/* convert any / to \ */
	/* note that in UTF-16, it's not possible to have '/' used as part */
	/* of a pair of codes representing a single UNICODE char */
	/* See: http://en.wikipedia.org/wiki/UTF-16 */
	while (*dst) {
		if (*dst == L'/')
			*dst = L'\\';
		++dst;
	}

	return conv_utf16_buffer[conv_utf16];
}

#define convert(a) convert_arg(a, 0)
#define convert_if_required(a) convert_arg(a, 1)

static BOOL GetReparseTagInfoByHandle(HANDLE hFile, FILE_ATTRIBUTE_TAG_INFO* lpFileAttributeTagInfo, DWORD dwFileAttributes)
{
	/* if not a reparse point, return no info */
	if ((dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) == 0) {
		lpFileAttributeTagInfo->FileAttributes = dwFileAttributes;
		lpFileAttributeTagInfo->ReparseTag = 0;
		return TRUE;
	}

	/* if not available, return no info */
	if (!ptr_GetFileInformationByHandleEx) {
		lpFileAttributeTagInfo->FileAttributes = dwFileAttributes;
		lpFileAttributeTagInfo->ReparseTag = 0;
		return TRUE;
	}

	/* do the real call */
	return ptr_GetFileInformationByHandleEx(hFile, FileAttributeTagInfo, lpFileAttributeTagInfo, sizeof(FILE_ATTRIBUTE_TAG_INFO));
}

/**
 * Converts Windows attr to the Unix stat format.
 */
static void windows_attr2stat(DWORD FileAttributes, DWORD ReparseTag, struct windows_stat* st)
{
	/* Convert special attributes */
	if ((FileAttributes & FILE_ATTRIBUTE_DEVICE) != 0) {
		st->st_mode = S_IFBLK;
		st->st_desc = "device";
	} else if ((FileAttributes & FILE_ATTRIBUTE_OFFLINE) != 0) { /* Offline */
		st->st_mode = S_IFCHR;
		st->st_desc = "offline";
	} else if ((FileAttributes & FILE_ATTRIBUTE_TEMPORARY) != 0) { /* Temporary */
		st->st_mode = S_IFCHR;
		st->st_desc = "temporary";
	} else if ((FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) != 0) { /* Reparse point */
		switch (ReparseTag) {
		/* if we don't have the ReparseTag information */
		case 0 :
			/* don't set the st_mode, to set it later calling lstat_sync() */
			st->st_mode = 0;
			st->st_desc = "unknown";
			break;
		/* for deduplicated files, assume that they are regular ones */
		case IO_REPARSE_TAG_DEDUP :
			if ((FileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0) {
				st->st_mode = S_IFDIR;
				st->st_desc = "directory-dedup";
			} else {
				st->st_mode = S_IFREG;
				st->st_desc = "regular-dedup";
			}
			break;
		case IO_REPARSE_TAG_SYMLINK :
			if ((FileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0) {
				st->st_mode = S_IFLNKDIR;
				st->st_desc = "reparse-point-symlink-dir";
			} else {
				st->st_mode = S_IFLNK;
				st->st_desc = "reparse-point-symlink-file";
			}
			break;
		/* all the other are skipped as reparse-point */
		case IO_REPARSE_TAG_MOUNT_POINT :
			st->st_mode = S_IFCHR;
			st->st_desc = "reparse-point-mount";
			break;
		case IO_REPARSE_TAG_NFS :
			st->st_mode = S_IFCHR;
			st->st_desc = "reparse-point-nfs";
			break;
		default :
			st->st_mode = S_IFCHR;
			st->st_desc = "reparse-point";
			break;
		}
	} else if ((FileAttributes & FILE_ATTRIBUTE_SYSTEM) != 0) { /* System */
		if ((FileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0) {
			st->st_mode = S_IFCHR;
			st->st_desc = "system-directory";
		} else {
			st->st_mode = S_IFREG;
			st->st_desc = "system-file";
		}
	} else {
		if ((FileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0) {
			st->st_mode = S_IFDIR;
			st->st_desc = "directory";
		} else {
			st->st_mode = S_IFREG;
			st->st_desc = "regular";
		}
	}

	/* store the HIDDEN attribute in a separate field */
	st->st_hidden = (FileAttributes & FILE_ATTRIBUTE_HIDDEN) != 0;
}

/**
 * Converts Windows info to the Unix stat format.
 */
static void windows_info2stat(const BY_HANDLE_FILE_INFORMATION* info, const FILE_ATTRIBUTE_TAG_INFO* tag, struct windows_stat* st)
{
	uint64_t mtime;

	windows_attr2stat(info->dwFileAttributes, tag->ReparseTag, st);

	st->st_size = info->nFileSizeHigh;
	st->st_size <<= 32;
	st->st_size |= info->nFileSizeLow;

	mtime = info->ftLastWriteTime.dwHighDateTime;
	mtime <<= 32;
	mtime |= info->ftLastWriteTime.dwLowDateTime;

	/*
	 * Convert to unix time
	 *
	 * How To Convert a UNIX time_t to a Win32 FILETIME or SYSTEMTIME
	 * http://support.microsoft.com/kb/167296
	 */
	mtime -= 116444736000000000LL;
	st->st_mtime = mtime / 10000000;
	st->st_mtimensec = (mtime % 10000000) * 100;

	st->st_ino = info->nFileIndexHigh;
	st->st_ino <<= 32;
	st->st_ino |= info->nFileIndexLow;

	st->st_dev = info->dwVolumeSerialNumber;

	/* GetFileInformationByHandle() ensures to return synced information */
	st->st_sync = 1;
}

/**
 * Converts Windows info to the Unix stat format.
 */
static void windows_stream2stat(const BY_HANDLE_FILE_INFORMATION* info, const FILE_ID_BOTH_DIR_INFO* stream, struct windows_stat* st)
{
	uint64_t mtime;

	/* The FILE_ID_BOTH_DIR_INFO doesn't have the ReparseTag information */
	/* we could use instead FILE_ID_EXTD_DIR_INFO, but it's available only */
	/* from Windows Server 2012 */
	windows_attr2stat(stream->FileAttributes, 0, st);

	st->st_size = stream->EndOfFile.QuadPart;

	mtime = stream->LastWriteTime.QuadPart;

	/*
	 * Convert to unix time
	 *
	 * How To Convert a UNIX time_t to a Win32 FILETIME or SYSTEMTIME
	 * http://support.microsoft.com/kb/167296
	 */
	mtime -= 116444736000000000LL;
	st->st_mtime = mtime / 10000000;
	st->st_mtimensec = (mtime % 10000000) * 100;

	st->st_ino = stream->FileId.QuadPart;

	st->st_dev = info->dwVolumeSerialNumber;

	/* directory listing doesn't ensure to return synced information */
	st->st_sync = 0;
}

/**
 * Converts Windows findfirst info to the Unix stat format.
 */
static void windows_finddata2stat(const WIN32_FIND_DATAW* info, struct windows_stat* st)
{
	uint64_t mtime;

	windows_attr2stat(info->dwFileAttributes, info->dwReserved0, st);

	st->st_size = info->nFileSizeHigh;
	st->st_size <<= 32;
	st->st_size |= info->nFileSizeLow;

	mtime = info->ftLastWriteTime.dwHighDateTime;
	mtime <<= 32;
	mtime |= info->ftLastWriteTime.dwLowDateTime;

	/*
	 * Convert to unix time
	 *
	 * How To Convert a UNIX time_t to a Win32 FILETIME or SYSTEMTIME
	 * http://support.microsoft.com/kb/167296
	 */
	mtime -= 116444736000000000LL;
	st->st_mtime = mtime / 10000000;
	st->st_mtimensec = (mtime % 10000000) * 100;

	/* No inode information available */
	st->st_ino = 0;

	/* No device information available */
	st->st_dev = 0;

	/* directory listing doesn't ensure to return synced information */
	st->st_sync = 0;
}

static void windows_finddata2dirent(const WIN32_FIND_DATAW* info, struct windows_dirent* dirent)
{
	const char* name;
	size_t len;

	name = u16tou8(info->cFileName, wcslen(info->cFileName), &len);

	if (len + 1 >= sizeof(dirent->d_name)) {
		fprintf(stderr, "Name too long\n");
		exit(EXIT_FAILURE);
	}

	memcpy(dirent->d_name, name, len);
	dirent->d_name[len] = 0;

	windows_finddata2stat(info, &dirent->d_stat);
}

static void windows_stream2dirent(const BY_HANDLE_FILE_INFORMATION* info, const FILE_ID_BOTH_DIR_INFO* stream, struct windows_dirent* dirent)
{
	const char* name;
	size_t len;

	name = u16tou8(stream->FileName, stream->FileNameLength / 2, &len);

	if (len + 1 >= sizeof(dirent->d_name)) {
		fprintf(stderr, "Name too long\n");
		exit(EXIT_FAILURE);
	}

	memcpy(dirent->d_name, name, len);
	dirent->d_name[len] = 0;

	windows_stream2stat(info, stream, &dirent->d_stat);
}

/**
 * Converts Windows error to errno.
 */
static void windows_errno(DWORD error)
{
	switch (error) {
	case ERROR_INVALID_HANDLE :
		/* we check for a bad handle calling _get_osfhandle() */
		/* and in such case we return EBADF */
		/* Other cases are here identified with EINVAL */
		errno = EINVAL;
		break;
	case ERROR_FILE_NOT_FOUND :
	case ERROR_PATH_NOT_FOUND : /* in GetFileAttributeW() if internal path not found */
		errno = ENOENT;
		break;
	case ERROR_ACCESS_DENIED : /* in CreateDirectoryW() if dir is scheduled for deletion */
	case ERROR_CURRENT_DIRECTORY : /* in RemoveDirectoryW() if removing the current directory */
	case ERROR_SHARING_VIOLATION : /* in RemoveDirectoryW() if in use */
	case ERROR_WRITE_PROTECT : /* when dealing with read-only media/snapshot and trying to write to them */
		errno = EACCES;
		break;
	case ERROR_ALREADY_EXISTS : /* in CreateDirectoryW() if already exists */
		errno = EEXIST;
		break;
	case ERROR_DISK_FULL :
		errno = ENOSPC;
		break;
	case ERROR_BUFFER_OVERFLOW :
		errno = ENAMETOOLONG;
		break;
	case ERROR_NOT_ENOUGH_MEMORY :
		errno = ENOMEM;
		break;
	case ERROR_NOT_SUPPORTED : /* in CreateSymlinkW() if not present in kernel32 */
		errno = ENOSYS;
		break;
	case ERROR_PRIVILEGE_NOT_HELD : /* in CreateSymlinkW if no SeCreateSymbolicLinkPrivilige permission */
		errno = EPERM;
		break;
	default :
		fprintf(stderr, "Unexpected Windows error %d.\n", (int)error);
		errno = EIO;
		break;
	}
}

int windows_fstat(int fd, struct windows_stat* st)
{
	BY_HANDLE_FILE_INFORMATION info;
	FILE_ATTRIBUTE_TAG_INFO tag;
	HANDLE h;

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	if (!GetFileInformationByHandle(h, &info)) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!GetReparseTagInfoByHandle(h, &tag, info.dwFileAttributes)) {
		windows_errno(GetLastError());
		return -1;
	}

	windows_info2stat(&info, &tag, st);

	return 0;
}

int windows_lstat(const char* file, struct windows_stat* st)
{
	HANDLE h;
	WIN32_FIND_DATAW data;

	/* FindFirstFileW by default gets information of symbolic links and not of their targets */
	h = FindFirstFileW(convert(file), &data);
	if (h == INVALID_HANDLE_VALUE) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!FindClose(h)) {
		windows_errno(GetLastError());
		return -1;
	}

	windows_finddata2stat(&data, st);

	return 0;
}

void windows_dirent_lstat(const struct windows_dirent* dd, struct windows_stat* st)
{
	memcpy(st, &dd->d_stat, sizeof(struct windows_stat));
}

int windows_mkdir(const char* file)
{
	if (!CreateDirectoryW(convert(file), 0)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int windows_rmdir(const char* file)
{
	if (!RemoveDirectoryW(convert(file))) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

static BOOL GetFilePhysicalOffset(HANDLE h, uint64_t* physical)
{
	STARTING_VCN_INPUT_BUFFER svib;
	unsigned char rpb_buffer[sizeof(RETRIEVAL_POINTERS_BUFFER)];
	RETRIEVAL_POINTERS_BUFFER* rpb = (RETRIEVAL_POINTERS_BUFFER*)&rpb_buffer;
	BOOL ret;
	DWORD n;

	/* in Wine FSCTL_GET_RETRIVIAL_POINTERS is not supported */
	if (is_wine) {
		*physical = FILEPHY_UNREPORTED_OFFSET;
		return TRUE;
	}

	/* set the output variable, just to be safe */
	rpb->ExtentCount = 0;

	/* read the physical address */
	svib.StartingVcn.QuadPart = 0;
	ret = DeviceIoControl(h, FSCTL_GET_RETRIEVAL_POINTERS, &svib, sizeof(svib), rpb_buffer, sizeof(rpb_buffer), &n, 0);
	if (!ret) {
		DWORD error = GetLastError();
		if (error == ERROR_MORE_DATA) {
			/* we ignore ERROR_MODE_DATA because we are interested only at the first entry */
			/* and this is the expected error if the files has more entries */
		} else if (error == ERROR_HANDLE_EOF) {
			/* if the file is small, it can be stored in the Master File Table (MFT) */
			/* and then it doesn't have a physical address */
			/* In such case we report a specific fake address, to report this special condition */
			/* that it's different from the 0 offset reported by the underline file system */
			*physical = FILEPHY_WITHOUT_OFFSET;
			return TRUE;
		} else if (error == ERROR_NOT_SUPPORTED) {
			/* for disks shared on network this operation is not supported */
			*physical = FILEPHY_UNREPORTED_OFFSET;
			return TRUE;
		} else {
			return FALSE;
		}
	}

	if (rpb->ExtentCount < 1)
		*physical = FILEPHY_UNREPORTED_OFFSET;
	else
		*physical = rpb->Extents[0].Lcn.QuadPart + FILEPHY_REAL_OFFSET;

	return TRUE;
}

int lstat_sync(const char* file, struct windows_stat* st, uint64_t* physical)
{
	BY_HANDLE_FILE_INFORMATION info;
	FILE_ATTRIBUTE_TAG_INFO tag;
	HANDLE h;

	/*
	 * Open the handle of the file.
	 *
	 * Use FILE_FLAG_BACKUP_SEMANTICS to open directories (it's just ignored for files).
	 * Use FILE_FLAG_OPEN_REPARSE_POINT to open symbolic links and not the their target.
	 */
	h = CreateFileW(convert(file), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, 0);
	if (h == INVALID_HANDLE_VALUE) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!GetFileInformationByHandle(h, &info)) {
		DWORD error = GetLastError();
		CloseHandle(h);
		windows_errno(error);
		return -1;
	}

	if (!GetReparseTagInfoByHandle(h, &tag, info.dwFileAttributes)) {
		DWORD error = GetLastError();
		CloseHandle(h);
		windows_errno(error);
		return -1;
	}

	/* read the physical offset, only if a pointer is provided */
	if (physical != 0) {
		if (!GetFilePhysicalOffset(h, physical)) {
			DWORD error = GetLastError();
			CloseHandle(h);
			windows_errno(error);
			return -1;
		}
	}

	if (!CloseHandle(h)) {
		windows_errno(GetLastError());
		return -1;
	}

	windows_info2stat(&info, &tag, st);

	return 0;
}

int windows_stat(const char* file, struct windows_stat* st)
{
	BY_HANDLE_FILE_INFORMATION info;
	FILE_ATTRIBUTE_TAG_INFO tag;
	HANDLE h;

	/*
	 * Open the handle of the file.
	 *
	 * Use FILE_FLAG_BACKUP_SEMANTICS to open directories (it's just ignored for files).
	 */
	h = CreateFileW(convert(file), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0);
	if (h == INVALID_HANDLE_VALUE) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!GetFileInformationByHandle(h, &info)) {
		DWORD error = GetLastError();
		CloseHandle(h);
		windows_errno(error);
		return -1;
	}

	if (!GetReparseTagInfoByHandle(h, &tag, info.dwFileAttributes)) {
		DWORD error = GetLastError();
		CloseHandle(h);
		windows_errno(error);
		return -1;
	}

	if (!CloseHandle(h)) {
		windows_errno(GetLastError());
		return -1;
	}

	windows_info2stat(&info, &tag, st);

	return 0;
}

int windows_ftruncate(int fd, off64_t off)
{
	HANDLE h;
	LARGE_INTEGER pos;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	pos.QuadPart = off;
	if (!SetFilePointerEx(h, pos, 0, FILE_BEGIN)) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!SetEndOfFile(h)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int windows_fsync(int fd)
{
	HANDLE h;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	/*
	 * "The FlushFileBuffers API can be used to flush all the outstanding data
	 * and metadata on a single file or a whole volume. However, frequent use
	 * of this API can cause reduced throughput. Internally, Windows uses the
	 * SCSI Synchronize Cache or the IDE/ATAPI Flush cache commands."
	 *
	 * From:
	 * "Windows Write Caching - Part 2 An overview for Application Developers"
	 * http://winntfs.com/2012/11/29/windows-write-caching-part-2-an-overview-for-application-developers/
	 */
	if (!FlushFileBuffers(h)) {
		DWORD error = GetLastError();

		switch (error) {
		case ERROR_INVALID_HANDLE :
			/*
			 * FlushFileBuffers returns this error if the handle
			 * doesn't support buffering, like the console output.
			 *
			 * We had a report that also ATA-over-Ethernet returns
			 * this error, but not enough sure to ignore it.
			 * So, we use now an extended error reporting.
			 */
			fprintf(stderr, "Unexpected Windows INVALID_HANDLE error in FlushFileBuffers().\n");
			fprintf(stderr, "Are you using ATA-over-Ethernet ? Please report it.\n");

			/* normal error processing */
			windows_errno(error);
			return -1;

		case ERROR_ACCESS_DENIED :
			/*
			 * FlushFileBuffers returns this error for read-only
			 * data, that cannot have to be flushed.
			 */
			return 0;

		default :
			windows_errno(error);
			return -1;
		}
	}

	return 0;
}

int windows_futimens(int fd, struct windows_timespec tv[2])
{
	HANDLE h;
	FILETIME ft;
	uint64_t mtime;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	/*
	 * Convert to windows time
	 *
	 * How To Convert a UNIX time_t to a Win32 FILETIME or SYSTEMTIME
	 * http://support.microsoft.com/kb/167296
	 */
	mtime = tv[0].tv_sec;
	mtime *= 10000000;
	mtime += tv[0].tv_nsec / 100;
	mtime += 116444736000000000;

	ft.dwHighDateTime = mtime >> 32;
	ft.dwLowDateTime = mtime;

	if (!SetFileTime(h, 0, 0, &ft)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int windows_rename(const char* from, const char* to)
{
	/*
	 * Implements an atomic rename in Windows.
	 * Not really atomic at now to support XP.
	 *
	 * Is an atomic file rename (with overwrite) possible on Windows?
	 * http://stackoverflow.com/questions/167414/is-an-atomic-file-rename-with-overwrite-possible-on-windows
	 */
	if (!MoveFileExW(convert(from), convert(to), MOVEFILE_REPLACE_EXISTING)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int windows_remove(const char* file)
{
	if (!DeleteFileW(convert(file))) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

FILE* windows_fopen(const char* file, const char* mode)
{
	return _wfopen(convert(file), u8tou16(mode));
}

int windows_open(const char* file, int flags, ...)
{
	va_list args;
	int ret;

	va_start(args, flags);
	if ((flags & O_CREAT) != 0)
		ret = _wopen(convert(file), flags, va_arg(args, int));
	else
		ret = _wopen(convert(file), flags);
	va_end(args);

	return ret;
}

struct windows_dir_struct {
	BY_HANDLE_FILE_INFORMATION info;
	WIN32_FIND_DATAW find;
	HANDLE h;
	struct windows_dirent entry;
	unsigned char* buffer;
	unsigned buffer_size;
	unsigned buffer_pos;
	int state;
};

#define DIR_STATE_EOF -1 /**< End of the dir stream */
#define DIR_STATE_EMPTY 0 /**< The entry is empty. */
#define DIR_STATE_FILLED 1 /**< The entry is valid. */

static windows_dir* windows_opendir_find(const char* dir)
{
	wchar_t* wdir;
	windows_dir* dirstream;
	size_t len;

	dirstream = malloc(sizeof(windows_dir));
	if (!dirstream) {
		fprintf(stderr, "Low memory\n");
		exit(EXIT_FAILURE);
	}

	wdir = convert(dir);

	/* add final / and * */
	len = wcslen(wdir);
	if (len != 0 && wdir[len - 1] != '\\')
		wdir[len++] = L'\\';
	wdir[len++] = L'*';
	wdir[len++] = 0;

	dirstream->h = FindFirstFileW(wdir, &dirstream->find);
	if (dirstream->h == INVALID_HANDLE_VALUE) {
		DWORD error = GetLastError();

		if (error == ERROR_FILE_NOT_FOUND) {
			dirstream->state = DIR_STATE_EOF;
			return dirstream;
		}

		free(dirstream);
		windows_errno(error);
		return 0;
	}

	windows_finddata2dirent(&dirstream->find, &dirstream->entry);
	dirstream->state = DIR_STATE_FILLED;

	return dirstream;
}

static struct windows_dirent* windows_readdir_find(windows_dir* dirstream)
{
	if (dirstream->state == DIR_STATE_EMPTY) {
		if (!FindNextFileW(dirstream->h, &dirstream->find)) {
			DWORD error = GetLastError();

			if (error != ERROR_NO_MORE_FILES) {
				windows_errno(error);
				return 0;
			}

			dirstream->state = DIR_STATE_EOF;
		} else {
			windows_finddata2dirent(&dirstream->find, &dirstream->entry);
			dirstream->state = DIR_STATE_FILLED;
		}
	}

	if (dirstream->state == DIR_STATE_FILLED) {
		dirstream->state = DIR_STATE_EMPTY;
		return &dirstream->entry;
	}

	/* otherwise it's the end of stream */
	assert(dirstream->state == DIR_STATE_EOF);
	errno = 0;

	return 0;
}

static int windows_closedir_find(windows_dir* dirstream)
{
	if (dirstream->h != INVALID_HANDLE_VALUE) {
		if (!FindClose(dirstream->h)) {
			DWORD error = GetLastError();

			free(dirstream);

			windows_errno(error);
			return -1;
		}
	}

	free(dirstream);

	return 0;
}

static int windows_first_stream(windows_dir* dirstream)
{
	FILE_ID_BOTH_DIR_INFO* fd;

	if (!ptr_GetFileInformationByHandleEx(dirstream->h, FileIdBothDirectoryInfo, dirstream->buffer, dirstream->buffer_size)) {
		DWORD error = GetLastError();

		if (error == ERROR_NO_MORE_FILES) {
			dirstream->state = DIR_STATE_EOF;
			return 0;
		}

		windows_errno(error);
		return -1;
	}

	/* get the first entry */
	dirstream->buffer_pos = 0;
	fd = (FILE_ID_BOTH_DIR_INFO*)dirstream->buffer;
	windows_stream2dirent(&dirstream->info, fd, &dirstream->entry);
	dirstream->state = DIR_STATE_FILLED;

	return 0;
}

static int windows_next_stream(windows_dir* dirstream)
{
	FILE_ID_BOTH_DIR_INFO* fd;

	/* last entry read */
	fd = (FILE_ID_BOTH_DIR_INFO*)(dirstream->buffer + dirstream->buffer_pos);

	/* check if there is a next one */
	if (fd->NextEntryOffset == 0) {
		/* if not, fill it up again */
		if (windows_first_stream(dirstream) != 0)
			return -1;
		return 0;
	}

	/* go to the next one */
	dirstream->buffer_pos += fd->NextEntryOffset;
	fd = (FILE_ID_BOTH_DIR_INFO*)(dirstream->buffer + dirstream->buffer_pos);
	windows_stream2dirent(&dirstream->info, fd, &dirstream->entry);
	dirstream->state = DIR_STATE_FILLED;

	return 0;
}

static windows_dir* windows_opendir_stream(const char* dir)
{
	windows_dir* dirstream;
	WCHAR* wdir;

	dirstream = malloc(sizeof(windows_dir));
	if (!dirstream) {
		fprintf(stderr, "Low memory\n");
		exit(EXIT_FAILURE);
	}

	wdir = convert(dir);

	/* uses a 64 kB buffer for reading directory */
	dirstream->buffer_size = 64 * 1024;
	dirstream->buffer = malloc(dirstream->buffer_size);
	if (!dirstream->buffer) {
		fprintf(stderr, "Low memory\n");
		exit(EXIT_FAILURE);
	}

	dirstream->h = CreateFileW(wdir, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0);
	if (dirstream->h == INVALID_HANDLE_VALUE) {
		DWORD error = GetLastError();
		free(dirstream->buffer);
		free(dirstream);
		windows_errno(error);
		return 0;
	}

	/* get dir information for the VolumeSerialNumber */
	/* this value is used for all the files in the dir */
	if (!GetFileInformationByHandle(dirstream->h, &dirstream->info)) {
		DWORD error = GetLastError();
		CloseHandle(dirstream->h);
		free(dirstream->buffer);
		free(dirstream);
		windows_errno(error);
		return 0;
	}

	if (windows_first_stream(dirstream) != 0) {
		CloseHandle(dirstream->h);
		free(dirstream->buffer);
		free(dirstream);
		return 0;
	}

	return dirstream;
}

static struct windows_dirent* windows_readdir_stream(windows_dir* dirstream)
{
	if (dirstream->state == DIR_STATE_EMPTY) {
		if (windows_next_stream(dirstream) != 0) {
			free(dirstream->buffer);
			free(dirstream);
			return 0;
		}
	}

	if (dirstream->state == DIR_STATE_FILLED) {
		dirstream->state = DIR_STATE_EMPTY;
		return &dirstream->entry;
	}

	/* otherwise it's the end of stream */
	assert(dirstream->state == DIR_STATE_EOF);
	errno = 0;

	return 0;
}

static int windows_closedir_stream(windows_dir* dirstream)
{
	if (dirstream->h != INVALID_HANDLE_VALUE) {
		if (!CloseHandle(dirstream->h)) {
			DWORD error = GetLastError();

			free(dirstream->buffer);
			free(dirstream);

			windows_errno(error);
			return -1;
		}
	}

	free(dirstream->buffer);
	free(dirstream);

	return 0;
}

windows_dir* windows_opendir(const char* dir)
{
	/* if we have GetFileInformationByHandleEx() we can read */
	/* the directory using a stream */
	if (!is_scan_winfind && ptr_GetFileInformationByHandleEx != 0)
		return windows_opendir_stream(dir);
	else
		return windows_opendir_find(dir);
}

struct windows_dirent* windows_readdir(windows_dir* dirstream)
{
	if (!is_scan_winfind && ptr_GetFileInformationByHandleEx != 0)
		return windows_readdir_stream(dirstream);
	else
		return windows_readdir_find(dirstream);
}

int windows_closedir(windows_dir* dirstream)
{
	if (!is_scan_winfind && ptr_GetFileInformationByHandleEx != 0)
		return windows_closedir_stream(dirstream);
	else
		return windows_closedir_find(dirstream);
}

int windows_dirent_hidden(struct dirent* dd)
{
	return dd->d_stat.st_hidden;
}

const char* windows_stat_desc(struct stat* st)
{
	return st->st_desc;
}

void windows_sleep(unsigned seconds)
{
	Sleep(seconds * 1000);
}

int windows_link(const char* existing, const char* file)
{
	if (!CreateHardLinkW(convert(file), convert(existing), 0)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int windows_symlink(const char* existing, const char* file)
{
	if (!ptr_CreateSymbolicLinkW) {
		windows_errno(ERROR_NOT_SUPPORTED);
		return -1;
	}

	/* We must convert to the extended-length \\?\ format if the path is too long */
	/* otherwise the link creation fails. */
	/* But we don't want to always convert it, to avoid to recreate */
	/* user symlinks different than they were before */
	if (!ptr_CreateSymbolicLinkW(convert(file), convert_if_required(existing), 0)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

/* Adds missing defition in MingW winnt.h */
#ifndef FSCTL_GET_REPARSE_POINT
#define FSCTL_GET_REPARSE_POINT 0x000900a8
#endif
#ifndef REPARSE_DATA_BUFFER_HEADER_SIZE
typedef struct _REPARSE_DATA_BUFFER {
	DWORD ReparseTag;
	WORD ReparseDataLength;
	WORD Reserved;
	_ANONYMOUS_UNION union {
		struct {
			WORD SubstituteNameOffset;
			WORD SubstituteNameLength;
			WORD PrintNameOffset;
			WORD PrintNameLength;
			ULONG Flags;
			WCHAR PathBuffer[1];
		} SymbolicLinkReparseBuffer;
		struct {
			WORD SubstituteNameOffset;
			WORD SubstituteNameLength;
			WORD PrintNameOffset;
			WORD PrintNameLength;
			WCHAR PathBuffer[1];
		} MountPointReparseBuffer;
		struct {
			BYTE DataBuffer[1];
		} GenericReparseBuffer;
	} DUMMYUNIONNAME;
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
#endif

int windows_readlink(const char* file, char* buffer, size_t size)
{
	HANDLE h;
	const char* name;
	size_t len;
	unsigned char rdb_buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
	REPARSE_DATA_BUFFER* rdb = (REPARSE_DATA_BUFFER*)rdb_buffer;
	BOOL ret;
	DWORD n;

	/*
	 * Open the handle of the file.
	 *
	 * Use FILE_FLAG_BACKUP_SEMANTICS to open directories (it's just ignored for files).
	 * Use FILE_FLAG_OPEN_REPARSE_POINT to open symbolic links and not the their target.
	 */
	h = CreateFileW(convert(file), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, 0);
	if (h == INVALID_HANDLE_VALUE) {
		windows_errno(GetLastError());
		return -1;
	}

	/* read the reparse point */
	ret = DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, 0, 0, rdb_buffer, sizeof(rdb_buffer), &n, 0);
	if (!ret) {
		windows_errno(GetLastError());
		CloseHandle(h);
		return -1;
	}

	CloseHandle(h);

	/* check if it's really a symbolic link */
	if (rdb->ReparseTag != IO_REPARSE_TAG_SYMLINK) {
		errno = EINVAL;
		return -1;
	}

	/* convert the name to UTF-8 */
	name = u16tou8(rdb->SymbolicLinkReparseBuffer.PathBuffer + rdb->SymbolicLinkReparseBuffer.PrintNameOffset,
			rdb->SymbolicLinkReparseBuffer.PrintNameLength / 2, &len);

	/* check for overflow */
	if (len > size) {
		len = size;
	}

	memcpy(buffer, name, len);

	return len;
}

int devuuid(uint64_t device, char* uuid, size_t uuid_size)
{
	/* just use the volume serial number returned in the device parameter */

	snprintf(uuid, uuid_size, "%08x", (unsigned)device);
	return 0;
}

int filephy(const char* file, uint64_t size, uint64_t* physical)
{
	HANDLE h;

	(void)size;

	/* open the handle of the file */
	h = CreateFileW(convert(file), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0);
	if (h == INVALID_HANDLE_VALUE) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!GetFilePhysicalOffset(h, physical)) {
		DWORD error = GetLastError();
		CloseHandle(h);
		windows_errno(error);
		return -1;
	}

	CloseHandle(h);
	return 0;
}

int fsinfo(const char* path, int* has_persistent_inode, uint64_t* total_space, uint64_t* free_space)
{
	/* all FAT/exFAT/NTFS when managed from Windows have persistent inodes */
	if (has_persistent_inode)
		*has_persistent_inode = 1;

	if (free_space || total_space) {
		ULARGE_INTEGER total_bytes;
		ULARGE_INTEGER total_free_bytes;
		DWORD attr;
		char dir[PATH_MAX];

		if (strlen(path) + 1 > sizeof(dir)) {
			windows_errno(ERROR_BUFFER_OVERFLOW);
			return -1;
		}

		strcpy(dir, path);

		/* get the file attributes */
		attr = GetFileAttributesW(convert(dir));
		if (attr == INVALID_FILE_ATTRIBUTES) {
			DWORD error = GetLastError();

			if (error != ERROR_FILE_NOT_FOUND) {
				windows_errno(error);
				return -1;
			}

			/* if it doesn't exist, we assume a file */
			/* and we check for the containing dir */
			attr = 0;
		}

		/* if it's not a directory, truncate the file name */
		if ((attr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
			char* slash = strrchr(dir, '/');

			/**
			 * Cut the file name, but leave the last slash.
			 *
			 * This is done because a MSDN comment about using of UNC paths.
			 *
			 * MSDN 'GetDiskFreeSpaceEx function'
			 * http://msdn.microsoft.com/en-us/library/windows/desktop/aa364937%28v=vs.85%29.aspx
			 * If this parameter is a UNC name, it must include a trailing backslash,
			 * for example, "\\MyServer\MyShare\".
			 */
			if (slash)
				slash[1] = 0;
		}

		/* get the free space of the directory */
		/* note that it must be a directory */
		if (!GetDiskFreeSpaceExW(convert(dir), 0, &total_bytes, &total_free_bytes)) {
			windows_errno(GetLastError());
			return -1;
		}

		if (total_space)
			*total_space = total_bytes.QuadPart;
		if (free_space)
			*free_space = total_free_bytes.QuadPart;
	}

	return 0;
}

#undef strerror

const char* windows_strerror(int err)
{
	/* get the normal C error from the specified err */
	const char* str = strerror(err);
	size_t len = strlen(str);

	/* adds space for GetLastError() */
	len += 32;

	/* reallocate */
	free(last_error);
	last_error = malloc(len);
	if (!last_error)
		return str;

	snprintf(last_error, len, "%s [%d/%u]", str, err, (unsigned)GetLastError());
	return last_error;
}

ssize_t windows_read(int fd, void* buffer, size_t size)
{
	HANDLE h;
	DWORD count;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	if (!ReadFile(h, buffer, size, &count, 0)) {
		windows_errno(GetLastError());
		return -1;
	}

	return count;
}

ssize_t windows_write(int fd, const void* buffer, size_t size)
{
	HANDLE h;
	DWORD count;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	if (!WriteFile(h, buffer, size, &count, 0)) {
		windows_errno(GetLastError());
		return -1;
	}

	return count;
}

off_t windows_lseek(int fd, off_t offset, int whence)
{
	HANDLE h;
	LARGE_INTEGER pos;
	LARGE_INTEGER ret;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	/* we support only SEEK_SET */
	if (whence != SEEK_SET) {
		errno = EINVAL;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

	pos.QuadPart = offset;
	if (!SetFilePointerEx(h, pos, &ret, FILE_BEGIN)) {
		windows_errno(GetLastError());
		return -1;
	}

	return ret.QuadPart;
}

ssize_t windows_pread(int fd, void* buffer, size_t size, off_t offset)
{
	HANDLE h;
	LARGE_INTEGER pos;
	DWORD count;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

retry:
	pos.QuadPart = offset;
	if (!SetFilePointerEx(h, pos, 0, FILE_BEGIN)) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!ReadFile(h, buffer, size, &count, 0)) {
		DWORD err = GetLastError();
		/*
		 * If Windows is not able to allocate memory from the PagedPool for the disk cache
		 * it could return the ERROR_NO_SYSTEM_RESOURCES error.
		 * In this case, the only possibility is to retry after a wait of few milliseconds.
		 *
		 * SQL Server reports operating system error 1450 or 1452 or 665 (retries)
		 * http://blogs.msdn.com/b/psssql/archive/2008/07/10/sql-server-reports-operating-system-error-1450-or-1452-or-665-retries.aspx
		 *
		 * 03-12-09 - ERROR_NO_SYSTEM_RESOURCES
		 * http://cbloomrants.blogspot.it/2009/03/03-12-09-errornosystemresources.html
		 *
		 * From SnapRAID Discussion Forum:
		 *
		 * Error reading file
		 * https://sourceforge.net/p/snapraid/discussion/1677233/thread/6657fdbf/
		 *
		 * Unexpected Windows ERROR_NO_SYSTEM_RESOURCES in pwrite(), retrying...
		 * https://sourceforge.net/p/snapraid/discussion/1677233/thread/a7c25ba9/
		 */
		if (err == ERROR_NO_SYSTEM_RESOURCES) {
			fprintf(stderr, "Unexpected Windows ERROR_NO_SYSTEM_RESOURCES in pread(), retrying...\n");
			Sleep(50);
			goto retry;
		}

		windows_errno(err);
		return -1;
	}

	return count;
}

ssize_t windows_pwrite(int fd, const void* buffer, size_t size, off_t offset)
{
	HANDLE h;
	LARGE_INTEGER pos;
	DWORD count;

	if (fd == -1) {
		errno = EBADF;
		return -1;
	}

	h = (HANDLE)_get_osfhandle(fd);
	if (h == INVALID_HANDLE_VALUE) {
		errno = EBADF;
		return -1;
	}

retry:
	pos.QuadPart = offset;
	if (!SetFilePointerEx(h, pos, 0, FILE_BEGIN)) {
		windows_errno(GetLastError());
		return -1;
	}

	if (!WriteFile(h, buffer, size, &count, 0)) {
		DWORD err = GetLastError();
		/* See windows_pread() for comments on this error management */
		if (err == ERROR_NO_SYSTEM_RESOURCES) {
			fprintf(stderr, "Unexpected Windows ERROR_NO_SYSTEM_RESOURCES in pwrite(), retrying...\n");
			Sleep(50);
			goto retry;
		}

		windows_errno(err);
		return -1;
	}

	return count;
}

uint64_t tick(void)
{
	LARGE_INTEGER t;

	if (!QueryPerformanceCounter(&t))
		return 0;

	return t.QuadPart;
}

int randomize(void* ptr, size_t size)
{
	if (!ptr_RtlGenRandom(ptr, size)) {
		windows_errno(GetLastError());
		return -1;
	}

	return 0;
}

int diskspin(tommy_list* list, int operation)
{
	(void)list;
	(void)operation;

	return -1;
}

#endif