Reimplement efile_drv as a dirty NIF

This improves the latency of file operations as dirty schedulers
are a bit more eager to run jobs than async threads, and use a
single global queue rather than per-thread queues, eliminating the
risk of a job stalling behind a long-running job on the same thread
while other async threads sit idle.

There's no such thing as a free lunch though; the lowered latency
comes at the cost of increased busy-waiting which may have an
adverse effect on some applications. This behavior can be tweaked
with the +sbwt flag, but unfortunately it affects all types of
schedulers and not just dirty ones. We plan to add type-specific
flags at a later stage.

sendfile has been moved to inet_drv to lessen the effect of a nasty
race; the cooperation between inet_drv and efile has never been
airtight and the socket dying at the wrong time (Regardless of
reason) could result in fd aliasing. Moving it to the inet driver
makes it impossible to trigger this by closing the socket in the
middle of a sendfile operation, while still allowing it to be
aborted -- something that can't be done if it stays in the file
driver.

The race still occurs if the controlling process dies in the short
window between dispatching the sendfile operation and the dup(2)
call in the driver, but it's much less likely to happen now.

A proper fix is in the works.

--

Notable functional differences:

* The use_threads option for file:sendfile/5 no longer has any
  effect.

* The file-specific DTrace probes have been removed. The same
  effect can be achieved with normal tracing together with the
  nif__entry/nif__return probes to track scheduling.

--

OTP-14256

1 files changed, 0 insertions, 2058 deletions

diff --git a/erts/emulator/drivers/win32/win_efile.c b/erts/emulator/drivers/win32/win_efile.c
deleted file mode 100644
index 2d366b5833..0000000000
--- a/erts/emulator/drivers/win32/win_efile.c
+++ /dev/null
@@ -1,2058 +0,0 @@
-/*
- * %CopyrightBegin%
- *
- * Copyright Ericsson AB 1997-2016. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * %CopyrightEnd%
- */
-/*
- * Purpose: Provides file and directory operations for Windows.
- */
-
-#include <windows.h>
-#ifdef HAVE_CONFIG_H
-#  include "config.h"
-#endif
-#include "sys.h"
-#include <ctype.h>
-#include <wchar.h>
-#include "erl_efile.h"
-
-#define DBG_TRACE_MASK 0
-/* 1 = file name ops
- * 2 = file descr ops
- * 4 = errors
- * 8 = path name conversion
- */
-#if !DBG_TRACE_MASK
-#  define DBG_TRACE(M,S)
-#  define DBG_TRACE1(M,FMT,A)
-#  define DBG_TRACE2(M,FMT,A,B)
-#else
-#  define DBG_TRACE(M,S) do { if ((M)&DBG_TRACE_MASK) fwprintf(stderr, L"DBG_TRACE %d: %s\r\n", __LINE__, (WCHAR*)(S)); }while(0)
-#  define DBG_TRACE1(M,FMT,A) do { if ((M)&DBG_TRACE_MASK) fwprintf(stderr, L"DBG_TRACE %d: " L##FMT L"\r\n", __LINE__, (A)); }while(0)
-#  define DBG_TRACE2(M,FMT,A,B) do { if ((M)&DBG_TRACE_MASK) fwprintf(stderr, L"DBG_TRACE %d: " L##FMT L"\r\n", __LINE__, (A), (B)); }while(0)
-#endif
-
-/*
- * Microsoft-specific function to map a WIN32 error code to a Posix errno.
- */
-
-#define ISSLASH(a)  ((a) == L'\\' || (a) == L'/')
-#define ISDIR(st) (((st).st_mode&S_IFMT) == S_IFDIR)
-#define ISREG(st) (((st).st_mode&S_IFMT) == S_IFREG)
-
-#define IS_DOT_OR_DOTDOT(s) \
-    ((s)[0] == L'.' && ((s)[1] == L'\0' || ((s)[1] == L'.' && (s)[2] == L'\0')))
-
-#define FILE_SHARE_FLAGS (FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE)
-
-#ifndef INVALID_FILE_ATTRIBUTES
-#define INVALID_FILE_ATTRIBUTES ((DWORD) 0xFFFFFFFF)
-#endif
-
-#define TICKS_PER_SECOND (10000000ULL)
-#define EPOCH_DIFFERENCE (11644473600LL)
-
-#define FILETIME_TO_EPOCH(epoch, ft) \
-    do { \
-	ULARGE_INTEGER ull; \
-	ull.LowPart  = (ft).dwLowDateTime; \
-	ull.HighPart = (ft).dwHighDateTime; \
-	(epoch) = ((ull.QuadPart / TICKS_PER_SECOND) - EPOCH_DIFFERENCE); \
-    } while(0)
-
-#define EPOCH_TO_FILETIME(ft, epoch) \
-    do { \
-	ULARGE_INTEGER ull; \
-	ull.QuadPart = (((epoch) + EPOCH_DIFFERENCE) * TICKS_PER_SECOND); \
-	(ft).dwLowDateTime = ull.LowPart; \
-	(ft).dwHighDateTime = ull.HighPart; \
-    } while(0)
-
-
-static int check_error(int result, Efile_error* errInfo);
-static int set_error(Efile_error* errInfo);
-static int set_os_errno(Efile_error* errInfo, DWORD os_errno);
-static int is_root_unc_name(const WCHAR *path);
-static int extract_root(WCHAR *name);
-static unsigned short dos_to_posix_mode(int attr, const WCHAR *name);
-
-
-struct wpath_tmp_buffer {
-    struct wpath_tmp_buffer* next;
-    WCHAR buffer[1];
-};
-
-typedef struct {
-    Efile_error* errInfo;
-    struct wpath_tmp_buffer* buf_list;
-}Efile_call_state;
-
-static void call_state_init(Efile_call_state* state, Efile_error* errInfo)
-{
-    state->errInfo = errInfo;
-    state->buf_list = NULL;
-}
-static WCHAR* wpath_tmp_alloc(Efile_call_state* state, size_t len)
-{
-    size_t sz = offsetof(struct wpath_tmp_buffer, buffer)
-	+ (len+1)*sizeof(WCHAR);
-    struct wpath_tmp_buffer* p = driver_alloc(sz);
-    p->next = state->buf_list;
-    state->buf_list = p;
-    return p->buffer;
-}
-static void call_state_free(Efile_call_state* state)
-{
-    while(state->buf_list) {
-	struct wpath_tmp_buffer* next = state->buf_list->next;
-	driver_free(state->buf_list);
-	state->buf_list = next;
-    }
-}
-static WCHAR* get_cwd_wpath_tmp(Efile_call_state* state)
-{
-    WCHAR dummy;
-    DWORD size = GetCurrentDirectoryW(0, &dummy);
-    WCHAR* ret = NULL;
-
-    if (size) {
-	ret = wpath_tmp_alloc(state, size);
-	if (!GetCurrentDirectoryW(size, ret)) {
-	    ret = NULL;
-	}
-    }
-    return ret;
-}
-static WCHAR* get_full_wpath_tmp(Efile_call_state* state,
-                                 const WCHAR* file,
-				 WCHAR** file_part,
-				 DWORD extra)
-{
-    WCHAR dummy;
-    DWORD size = GetFullPathNameW(file, 0, &dummy, NULL);
-    WCHAR* ret = NULL;
-
-    if (size) {
-	int ok;
-	ret = wpath_tmp_alloc(state, size + extra);
-	if (file_part) {
-	    ok = (GetFullPathNameW(file, size, ret, file_part) != 0);
-	}
-	else {
-	    ok = (_wfullpath(ret, file, size) != NULL);
-	}
-	if (!ok) {
-	    ret = NULL;
-	}
-    }
-    return ret;
-}
-
-static void ensure_wpath_max(Efile_call_state* state, WCHAR** pathp, size_t max);
-static int do_rmdir(Efile_call_state*, char* name);
-static int do_rename(Efile_call_state*, char* src, char* dst);
-static int do_readdir(Efile_call_state*, char* name, EFILE_DIR_HANDLE*, char* buffer, size_t *size);
-static int do_fileinfo(Efile_call_state*, Efile_info*, char* orig_name, int info_for_link);
-static char* do_readlink(Efile_call_state*, char* name, char* buffer, size_t size);
-static int do_altname(Efile_call_state*, char* orig_name, char* buffer, size_t size);
-
-
-static int errno_map(DWORD last_error) {
-
-    switch (last_error) {
-    case ERROR_SUCCESS:
-	return 0;
-    case ERROR_INVALID_FUNCTION:
-    case ERROR_INVALID_DATA:
-    case ERROR_INVALID_PARAMETER:
-    case ERROR_INVALID_TARGET_HANDLE:
-    case ERROR_INVALID_CATEGORY:
-    case ERROR_NEGATIVE_SEEK:
-	return EINVAL;
-    case ERROR_DIR_NOT_EMPTY:
-	return EEXIST;
-    case ERROR_BAD_FORMAT:
-	return ENOEXEC;
-    case ERROR_PATH_NOT_FOUND:
-    case ERROR_FILE_NOT_FOUND:
-    case ERROR_NO_MORE_FILES:
-	return ENOENT;
-    case ERROR_TOO_MANY_OPEN_FILES:
-	return EMFILE;
-    case ERROR_ACCESS_DENIED:
-    case ERROR_INVALID_ACCESS:
-    case ERROR_CURRENT_DIRECTORY:
-    case ERROR_SHARING_VIOLATION:
-    case ERROR_LOCK_VIOLATION:
-    case ERROR_INVALID_PASSWORD:
-    case ERROR_DRIVE_LOCKED:
-	return EACCES;
-    case ERROR_INVALID_HANDLE:
-	return EBADF;
-    case ERROR_NOT_ENOUGH_MEMORY:
-    case ERROR_OUTOFMEMORY:
-    case ERROR_OUT_OF_STRUCTURES:
-	return ENOMEM;
-    case ERROR_INVALID_DRIVE:
-    case ERROR_BAD_UNIT:
-    case ERROR_NOT_READY:
-    case ERROR_REM_NOT_LIST:
-    case ERROR_DUP_NAME:
-    case ERROR_BAD_NETPATH:
-    case ERROR_NETWORK_BUSY:
-    case ERROR_DEV_NOT_EXIST:
-    case ERROR_BAD_NET_NAME:
-	return ENXIO;
-    case ERROR_NOT_SAME_DEVICE:
-	return EXDEV;
-    case ERROR_WRITE_PROTECT:
-	return EROFS;
-    case ERROR_BAD_LENGTH:
-    case ERROR_BUFFER_OVERFLOW:
-	return E2BIG;
-    case ERROR_SEEK:
-    case ERROR_SECTOR_NOT_FOUND:
-	return ESPIPE;
-    case ERROR_NOT_DOS_DISK:
-	return ENODEV;
-    case ERROR_GEN_FAILURE:
-	return ENODEV;
-    case ERROR_SHARING_BUFFER_EXCEEDED:
-    case ERROR_NO_MORE_SEARCH_HANDLES:
-	return EMFILE;
-    case ERROR_HANDLE_EOF:
-    case ERROR_BROKEN_PIPE:
-	return EPIPE;
-    case ERROR_HANDLE_DISK_FULL:
-    case ERROR_DISK_FULL:
-	return ENOSPC;
-    case ERROR_NOT_SUPPORTED:
-	return ENOTSUP;
-    case ERROR_FILE_EXISTS:
-    case ERROR_ALREADY_EXISTS:
-    case ERROR_CANNOT_MAKE:
-	return EEXIST;
-    case ERROR_ALREADY_ASSIGNED:
-	return EBUSY;
-    case ERROR_NO_PROC_SLOTS:
-	return EAGAIN;
-    case ERROR_CANT_RESOLVE_FILENAME:
-	return EMLINK;
-    case ERROR_PRIVILEGE_NOT_HELD:
-	return EPERM;
-    case ERROR_ARENA_TRASHED:
-    case ERROR_INVALID_BLOCK:
-    case ERROR_BAD_ENVIRONMENT:
-    case ERROR_BAD_COMMAND:
-    case ERROR_CRC:
-    case ERROR_OUT_OF_PAPER:
-    case ERROR_READ_FAULT:
-    case ERROR_WRITE_FAULT:
-    case ERROR_WRONG_DISK:
-    case ERROR_NET_WRITE_FAULT:
-	return EIO;
-    default: /* not to do with files I expect. */
-	return EIO;
-    }	
-}
-
-static int
-check_error(int result, Efile_error* errInfo)
-{
-    if (result < 0) {
-	errInfo->posix_errno = errno;
-	errInfo->os_errno = GetLastError();
-	DBG_TRACE2(4, "ERROR os_error=%d errno=%d @@@@@@@@@@@@@@@@@@@@@@@@@@@@",
-	        errInfo->os_errno, errInfo->posix_errno);
-	return 0;
-    }
-    return 1;
-}
-
-static void
-save_last_error(Efile_error* errInfo)
-{
-    errInfo->posix_errno = errno;
-    errInfo->os_errno = GetLastError();
-    DBG_TRACE2(4, "ERROR os_error=%d errno=%d $$$$$$$$$$$$$$$$$$$$$$$$$$$$$",
-	errInfo->os_errno, errInfo->posix_errno);
-}
-
-
-/*
- * Fills the provided error information structure with information
- * with the error code given by GetLastError() and its corresponding
- * Posix error number.
- *
- * Returns 0.
- */
-
-static int
-set_error(Efile_error* errInfo)
-{
-    set_os_errno(errInfo, GetLastError());
-    return 0;
-}
-
-
-static int
-set_os_errno(Efile_error* errInfo, DWORD os_errno)
-{
-    errInfo->os_errno = os_errno;
-    errInfo->posix_errno = errno_map(os_errno);
-    DBG_TRACE2(4, "ERROR os_error=%d errno=%d ############################",
-	    errInfo->os_errno, errInfo->posix_errno);
-    return 0;
-}
-
-int
-efile_init() {
-   return 1;
-}
-
-/*
- * A writev with Unix semantics, but with Windows arguments 
- */
-static int 
-win_writev(Efile_error* errInfo,
-	   HANDLE fd,                  /* handle to file */
-	   FILE_SEGMENT_ELEMENT iov[], /* array of buffer pointers */
-	   DWORD *size)                /* number of bytes to write */
-{
-    OVERLAPPED ov;
-    ov.Offset = 0L;
-    ov.OffsetHigh = 0L;
-    ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
-    if (ov.hEvent == NULL)
-	return set_error(errInfo);
-    if (! write_file_gather(fd, iov, *size, NULL, &ov))
-	return set_error(errInfo);
-    if (WaitForSingleObject(ov.hEvent, INFINITE) != WAIT_OBJECT_0)
-	return set_error(errInfo);
-    if (! GetOverlappedResult(fd, &ov, size, FALSE))
-	return set_error(errInfo);
-    return 1;
-}
-
-
-/* Check '*pathp' and convert it if needed to something that windows will accept.
- * Typically use UNC path with \\?\ prefix if absolute path is longer than 260.
- */
-static void ensure_wpath(Efile_call_state* state, WCHAR** pathp)
-{
-    ensure_wpath_max(state, pathp, MAX_PATH);
-}
-
-static void ensure_wpath_max(Efile_call_state* state, WCHAR** pathp, size_t max)
-{
-    WCHAR* path = *pathp;
-    WCHAR* p;
-    size_t len = wcslen(path);
-    int unc_fixup = 0;
-
-    if (path[0] == 0) {
-	DBG_TRACE(8, L"Let empty path pass through");
-	return;
-    }
-
-    DBG_TRACE1(8,"IN: %s", path);
-
-    if (path[1] == L':' && ISSLASH(path[2])) { /* absolute path */
-	if (len >= max) {
-	    WCHAR *src, *dst;
-
-	    *pathp = wpath_tmp_alloc(state, 4+len+1);
-	    dst = *pathp;
-	    wcscpy(dst, L"\\\\?\\");
-	    for (src=path,dst+=4; *src; src++) {
-		if (*src == L'/') {
-		    if (dst[-1] != L'\\') {
-			*dst++ =  L'\\';
-		    }
-		    /*else ignore redundant slashes */
-		}
-		else
-		    *dst++ = *src;
-	    }
-	    *dst = 0;
-	    unc_fixup = 1;
-	}
-    }
-    else if (!(ISSLASH(path[0]) && ISSLASH(path[1]))) { /* relative path */
-	DWORD cwdLen = GetCurrentDirectoryW(0, NULL);
-	DWORD absLen = cwdLen + 1 + len;
-	if (absLen >= max) {
-	    WCHAR *fullPath = wpath_tmp_alloc(state, 4+4+absLen);
-	    DWORD fullLen;
-
-	    fullLen = GetFullPathNameW(path, 4 + absLen, fullPath+4, NULL);
-	    if (fullLen >= 4+absLen) {
-		*pathp = path;
-		DBG_TRACE2(8,"ensure_wpath FAILED absLen=%u %s", (int)absLen, path);
-		return;
-	    }
-	    /* GetFullPathNameW can return paths longer than MAX_PATH without the \\?\ prefix.
-	     * At least seen on Windows 7. Go figure...
-	     */
-	    if (fullLen >= max && wcsncmp(fullPath+4, L"\\\\?\\", 4) != 0) {
-		wcsncpy(fullPath, L"\\\\?\\", 4);
-		*pathp = fullPath;
-	    }
-	    else {
-		*pathp = fullPath + 4;
-	    }
-	}
-    }
-
-    if (unc_fixup) {
-	WCHAR* endp;
-
-	p = *pathp;
-	len = wcslen(p);
-	endp = p + len;
-	if (len > 4) {
-	    p += 4;
-	    while (*p) {
-		if (p[0] == L'\\' && p[1] == L'.') {
-		    if (p[2] == L'\\' || !p[2]) { /* single dot */
-			wmemmove(p, p+2, (&endp[1] - &p[2]));
-			endp -= 2;
-		    }
-		    else if (p[2] == L'.' && (p[3] == L'\\' || !p[3])) { /* double dot */
-			WCHAR* r;
-			for (r=p-1; *r == L'\\'; --r)
-			    /*skip redundant slashes*/;
-			for (; *r != L'\\'; --r)
-			    /*find start of prev directory*/;
-			if (r < *pathp + 6)
-			    break;
-			wmemmove(r, p+3, (&endp[1] - &p[3]));
-			p = r;
-		    }
-		    else p += 3;
-		}
-		else ++p;
-	    }
-	}
-    }
-    DBG_TRACE1(8,"OUT: %s", *pathp);
-}
-
-int
-efile_mkdir(Efile_error* errInfo,	/* Where to return error codes. */
-	    char* name)			/* Name of directory to create. */
-{
-    Efile_call_state state;
-    WCHAR* wname = (WCHAR*)name;
-    int ret;
-
-    DBG_TRACE(1, name);
-    call_state_init(&state, errInfo);
-    ensure_wpath_max(&state, &wname, 248); /* Yes, 248 limit for normal paths */
-
-    ret = (int) CreateDirectoryW(wname, NULL);
-    if (!ret)
-	set_error(errInfo);
-
-    call_state_free(&state);
-    return ret;
-}
-
-int
-efile_rmdir(Efile_error* errInfo,	/* Where to return error codes. */
-	    char* name)			/* Name of directory to delete. */
-{
-    Efile_call_state state;
-    int ret;
-
-    DBG_TRACE(1, name);
-    call_state_init(&state, errInfo);
-    ret = do_rmdir(&state, name);
-    call_state_free(&state);
-    return ret;
-}
-
-static int do_rmdir(Efile_call_state* state, char* name)
-{
-    OSVERSIONINFO os;
-    DWORD attr;
-    WCHAR *wname = (WCHAR *) name;
-    WCHAR *buffer = NULL;
-
-    ensure_wpath(state, &wname);
-
-    if (RemoveDirectoryW(wname) != FALSE) {
-	return 1;
-    }
-    errno = errno_map(GetLastError());
-    if (errno == EACCES) {
-	attr = GetFileAttributesW(wname);
-	if (attr != (DWORD) -1) {
-	    if ((attr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
-		/* 
-		 * Windows 95 reports calling RemoveDirectory on a file as an 
-		 * EACCES, not an ENOTDIR.
-		 */
-		
-		errno = ENOTDIR;
-		goto end;
-	    }
-
-	    /* 
-	     * Windows 95 reports removing a non-empty directory as
-	     * an EACCES, not an EEXIST.  If the directory is not empty,
-	     * change errno so caller knows what's going on.
-	     */
-
-	    os.dwOSVersionInfoSize = sizeof(os);
-	    GetVersionEx(&os);
-	    if (os.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) {
-		HANDLE handle;
-		WIN32_FIND_DATAW data;
-		int len = wcslen(wname);
-
-		buffer = wpath_tmp_alloc(state, len + 4);
-		wcscpy(buffer, wname);
-		if (buffer[0] && buffer[len-1] != L'\\' && buffer[len-1] != L'/') {
-		    wcscat(buffer, L"\\");
-		}
-		wcscat(buffer, L"*.*");
-		handle = FindFirstFileW(buffer, &data);
-		if (handle != INVALID_HANDLE_VALUE) {
-		    while (1) {
-			if ((wcscmp(data.cFileName, L".") != 0)
-				&& (wcscmp(data.cFileName, L"..") != 0)) {
-			    /*
-			     * Found something in this directory.
-			     */
-
-			    errno = EEXIST;
-			    break;
-			}
-			if (FindNextFileW(handle, &data) == FALSE) {
-			    break;
-			}
-		    }
-		    FindClose(handle);
-		}
-	    }
-	}
-    }
-
-    if (errno == ENOTEMPTY) {
-	/* 
-	 * Posix allows both EEXIST or ENOTEMPTY, but we'll always
-	 * return EEXIST to allow easy matching in Erlang code.
-	 */
-
-	errno = EEXIST;
-    }
-
- end:
-    save_last_error(state->errInfo);
-    return 0;
-}
-
-int
-efile_delete_file(Efile_error* errInfo,		/* Where to return error codes. */
-		  char* name)			/* Name of file to delete. */
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(1, name);
-    call_state_init(&state, errInfo);
-    ret = do_delete_file(&state, name);
-    call_state_free(&state);
-    return ret;
-}
-
-static int do_delete_file(Efile_call_state* state, char* name)
-{
-    DWORD attr;
-    WCHAR *wname = (WCHAR *) name;
-
-    ensure_wpath(state, &wname);
-
-    if (DeleteFileW(wname) != FALSE) {
-	return 1;
-    }
-
-    errno = errno_map(GetLastError());
-    if (errno == EACCES) {
-        attr = GetFileAttributesW(wname);
-	if (attr != (DWORD) -1) {
-	    if (attr & FILE_ATTRIBUTE_DIRECTORY) {
-		/*
-		 * Windows NT reports removing a directory as EACCES instead
-		 * of EPERM.
-		 */
-
-		errno = EPERM;
-	    }
-	}
-    } else if (errno == ENOENT) {
-        attr = GetFileAttributesW(wname);
-	if (attr != (DWORD) -1) {
-	    if (attr & FILE_ATTRIBUTE_DIRECTORY) {
-	    	/*
-		 * Windows 95 reports removing a directory as ENOENT instead 
-		 * of EPERM.
-		 */
-
-		errno = EPERM;
-	    }
-	}
-    } else if (errno == EINVAL) {
-	/*
-	 * Windows NT reports removing a char device as EINVAL instead of
-	 * EACCES.
-	 */
-	
-	errno = EACCES;
-    }
-
-    return check_error(-1, state->errInfo);
-}
-
-/*
- *---------------------------------------------------------------------------
- *
- *      Changes the name of an existing file or directory, from src to dst.
- *	If src and dst refer to the same file or directory, does nothing
- *	and returns success.  Otherwise if dst already exists, it will be
- *	deleted and replaced by src subject to the following conditions:
- *	    If src is a directory, dst may be an empty directory.
- *	    If src is a file, dst may be a file.
- *	In any other situation where dst already exists, the rename will
- *	fail.  
- *
- *	Some possible error codes:
- *
- *	EACCES:     src or dst parent directory can't be read and/or written.
- *	EEXIST:	    dst is a non-empty directory.
- *	EINVAL:	    src is a root directory or dst is a subdirectory of src.
- *	EISDIR:	    dst is a directory, but src is not.
- *	ENOENT:	    src doesn't exist, or src or dst is "".
- *	ENOTDIR:    src is a directory, but dst is not.  
- *	EXDEV:	    src and dst are on different filesystems.
- *	
- * Side effects:
- *	The implementation of rename may allow cross-filesystem renames,
- *	but the caller should be prepared to emulate it with copy and
- *	delete if errno is EXDEV.
- *
- *---------------------------------------------------------------------------
- */
-
-int
-efile_rename(Efile_error* errInfo, char* src, char* dst)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(1, src);
-    call_state_init(&state, errInfo);
-    ret = do_rename(&state, src, dst);
-    call_state_free(&state);
-    return ret;
-}
-
-static int
-do_rename(Efile_call_state* state,
-	  char* src,			/* Original name. */
-	  char* dst)			/* New name. */
-{
-    DWORD srcAttr, dstAttr;
-    WCHAR *wsrc = (WCHAR *) src;
-    WCHAR *wdst = (WCHAR *) dst;
-
-    ensure_wpath(state, &wsrc);
-    ensure_wpath(state, &wdst);
-
-    if (MoveFileW(wsrc, wdst) != FALSE) {
-	return 1;
-    }
-
-    errno = errno_map(GetLastError());
-    srcAttr = GetFileAttributesW(wsrc);
-    dstAttr = GetFileAttributesW(wdst);
-    if (srcAttr == (DWORD) -1) {
-	srcAttr = 0;
-    }
-    if (dstAttr == (DWORD) -1) {
-	dstAttr = 0;
-    }
-
-    if (errno == EBADF) {
-	errno = EACCES;
-	return check_error(-1, state->errInfo);
-    }
-    if (errno == EACCES) {
-	decode:
-	if (srcAttr & FILE_ATTRIBUTE_DIRECTORY) {
-	    WCHAR *srcPath, *dstPath;
-	    WCHAR *srcRest, *dstRest;
-	    int size;
-
-	    srcPath = get_full_wpath_tmp(state, wsrc, &srcRest, 0);
-	    if (!srcPath) {
-		save_last_error(state->errInfo);
-		return 0;
-	    }
-
-	    dstPath = get_full_wpath_tmp(state, wdst, &dstRest, 0);
-	    if (!dstPath) {
-		save_last_error(state->errInfo);
-		return 0;
-	    }
-
-	    if (srcRest == NULL) {
-		srcRest = srcPath + wcslen(srcPath);
-	    }
-	    if (_wcsnicmp(srcPath, dstPath, srcRest - srcPath) == 0) {
-		/*
-		 * Trying to move a directory into itself.
-		 */
-
-		errno = EINVAL;
-	    }
-	    if (extract_root(srcPath)) {
-		/*
-		 * Attempt to move a root directory.  Never allowed.
-		 */
-		errno = EINVAL;
-	    }
-
-	    (void) extract_root(dstPath);
-	    if (dstPath[0] == L'\0') {
-		/*
-		 * The filename was invalid.  (Don't know why,
-		 * but play it safe.)
-		 */
-		errno = EINVAL;
-	    }
-	    if (_wcsicmp(srcPath, dstPath) != 0) {
-		/*
-		 * If src is a directory and dst filesystem != src
-		 * filesystem, errno should be EXDEV.  It is very
-		 * important to get this behavior, so that the caller
-		 * can respond to a cross filesystem rename by
-		 * simulating it with copy and delete.  The MoveFile
-		 * system call already handles the case of moving a
-		 * *file* between filesystems.
-		 */
-
-		errno = EXDEV;
-	    }
-	}
-
-	/*
-	 * Other types of access failure is that dst is a read-only
-	 * filesystem, that an open file referred to src or dest, or that
-	 * src or dest specified the current working directory on the
-	 * current filesystem.  EACCES is returned for those cases.
-	 */
-
-    } else if (errno == EEXIST) {
-	/*
-	 * Reports EEXIST any time the target already exists.  If it makes
-	 * sense, remove the old file and try renaming again.
-	 */
-
-	if (srcAttr & FILE_ATTRIBUTE_DIRECTORY) {
-	    if (dstAttr & FILE_ATTRIBUTE_DIRECTORY) {
-		/*
-		 * Overwrite empty dst directory with src directory.  The
-		 * following call will remove an empty directory.  If it
-		 * fails, it's because it wasn't empty.
-		 */
-
-		if (RemoveDirectoryW(wdst)) {
-		    /*
-		     * Now that that empty directory is gone, we can try
-		     * renaming again.  If that fails, we'll put this empty
-		     * directory back, for completeness.
-		     */
-
-		    if (MoveFileW(wsrc, wdst) != FALSE) {
-			return 1;
-		    }
-
-		    /*
-		     * Some new error has occurred.  Don't know what it
-		     * could be, but report this one.
-		     */
-
-		    errno = errno_map(GetLastError());
-		    CreateDirectoryW(wdst, NULL);
-		    SetFileAttributesW(wdst, dstAttr);
-		    if (errno == EACCES) {
-			/*
-			 * Decode the EACCES to a more meaningful error.
-			 */
-
-			goto decode;
-		    }
-		}
-	    } else {	/* (dstAttr & FILE_ATTRIBUTE_DIRECTORY) == 0 */
-		errno = ENOTDIR;
-	    }
-	} else {    /* (srcAttr & FILE_ATTRIBUTE_DIRECTORY) == 0 */
-	    if (dstAttr & FILE_ATTRIBUTE_DIRECTORY) {
-		errno = EISDIR;
-	    } else {
-		/*
-		 * Overwrite existing file by:
-		 * 
-		 * 1. Rename existing file to temp name.
-		 * 2. Rename old file to new name.
-		 * 3. If success, delete temp file.  If failure,
-		 *    put temp file back to old name.
-		 */
-
-		WCHAR *tempName;
-		int result;
-		WCHAR *rest;
-		
-		tempName = get_full_wpath_tmp(state, wdst, &rest, 14);
-		if (!tempName || !rest) {
-		    save_last_error(state->errInfo);
-		    return 0;
-		}
-
-		*rest = L'\0';
-		result = -1;
-		if (GetTempFileNameW(tempName, L"erlr", 0, tempName) != 0) {
-		    /*
-		     * Strictly speaking, need the following DeleteFile and
-		     * MoveFile to be joined as an atomic operation so no
-		     * other app comes along in the meantime and creates the
-		     * same temp file.
-		     */
-		     
-		    DeleteFileW(tempName);
-		    if (MoveFileW(wdst, tempName) != FALSE) {
-			if (MoveFileW(wsrc, wdst) != FALSE) {
-			    SetFileAttributesW(tempName, FILE_ATTRIBUTE_NORMAL);
-			    DeleteFileW(tempName);
-			    return 1;
-			} else {
-			    DeleteFileW(wdst);
-			    MoveFileW(tempName, wdst);
-			}
-		    } 
-
-		    /*
-		     * Can't backup dst file or move src file.  Return that
-		     * error.  Could happen if an open file refers to dst.
-		     */
-
-		    errno = errno_map(GetLastError());
-		    if (errno == EACCES) {
-			/*
-			 * Decode the EACCES to a more meaningful error.
-			 */
-			goto decode;
-		    }
-		}
-		return result;
-	    }
-	}
-    }
-    return check_error(-1, state->errInfo);
-}
-
-int
-efile_chdir(Efile_error* errInfo,	/* Where to return error codes. */
-	    char* name)			/* Name of directory to make current. */
-{

-    /* We don't even try to handle long paths here

-     * as current working directory is always limited to MAX_PATH

-     * even if we use UNC paths and SetCurrentDirectoryW()

-     */

-    int success = check_error(_wchdir((WCHAR *) name), errInfo);

-    if (!success && errInfo->posix_errno == EINVAL)

-	/* POSIXification of errno */

-	errInfo->posix_errno = ENOENT;
-    return success;
-}
-
-int
-efile_getdcwd(Efile_error* errInfo,		/* Where to return error codes. */
-	      int drive,			/* 0 - current, 1 - A, 2 - B etc. */
-	      char* buffer,			/* Where to return the current directory. */
-	      size_t size)			/* Size of buffer. */
-{
-    WCHAR *wbuffer = (WCHAR *) buffer;
-    size_t wbuffer_size = size / 2; 
-    DBG_TRACE(1, L"#getdcwd#");
-    if (_wgetdcwd(drive, wbuffer, wbuffer_size) == NULL) {
-	return check_error(-1, errInfo);
-    }
-    DBG_TRACE1(8, "getdcwd OS=%s", wbuffer);
-    if (wcsncmp(wbuffer, L"\\\\?\\", 4) == 0) {
-	wmemmove(wbuffer, wbuffer+4, wcslen(wbuffer+4)+1);
-    }
-    for ( ; *wbuffer; wbuffer++) 
-	if (*wbuffer == L'\\')
-	    *wbuffer = L'/';
-    DBG_TRACE1(8, "getdcwd ERLANG=%s", (WCHAR*)buffer);
-    return 1;
-}
-
-int
-efile_readdir(Efile_error* errInfo, char* name, EFILE_DIR_HANDLE* dir_handle,
-	      char* buffer, size_t *size)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(dir_handle?2:1, name);
-    call_state_init(&state, errInfo);
-    ret = do_readdir(&state, name, dir_handle, buffer, size);
-    call_state_free(&state);
-    return ret;
-}
-
-static int do_readdir(Efile_call_state* state,
-                      char* name,                   /* Name of directory to list */
-		      EFILE_DIR_HANDLE* dir_handle, /* Handle of opened directory or NULL */
-		      char* buffer,                 /* Buffer to put one filename in */
-		      size_t *size)                 /* in-out size of buffer/size of filename excluding zero
-					               termination in bytes*/
-{
-    HANDLE dir;			/* Handle to directory. */
-    WIN32_FIND_DATAW findData;	/* Data found by FindFirstFile() or FindNext(). */
-    /* Alignment is not honored, this works on x86 because of alignment fixup by processor.
-       Not perfect, but faster than alinging by hand (really) */
-    WCHAR *wbuffer = (WCHAR *) buffer;
-
-    /*
-     * First time we must setup everything.
-     */
-
-    if (*dir_handle == NULL) {
-	WCHAR *wname = (WCHAR *) name;
-	WCHAR* wildcard;
-	int length;
-	WCHAR* s;
-
-	ensure_wpath_max(state, &wname, MAX_PATH-2);
-	length = wcslen(wname);
-
-	wildcard = wpath_tmp_alloc(state, length+3);
-
-	wcscpy(wildcard, wname);
-	s = wildcard+length-1;
-	if (*s != L'/' && *s != L'\\')
-	    *++s = L'\\';
-	*++s = L'*';
-	*++s = L'\0';
-	DEBUGF(("Reading %ws\n", wildcard));
-	dir = FindFirstFileW(wildcard, &findData);
-	if (dir == INVALID_HANDLE_VALUE) {
-	    set_error(state->errInfo);
-	    return 0;
-	}
-	*dir_handle = (EFILE_DIR_HANDLE) dir;
-
-	if (!IS_DOT_OR_DOTDOT(findData.cFileName)) {
-	    wcscpy(wbuffer, findData.cFileName);
-	    *size = wcslen(wbuffer)*2;
-	    return 1;
-	}
-    }
-
-    /*
-     * Retrieve the name of the next file using the directory handle.
-     */
-
-    dir = (HANDLE) *dir_handle;
-
-    for (;;) {
-	if (FindNextFileW(dir, &findData)) {
-	    if (IS_DOT_OR_DOTDOT(findData.cFileName))
-		continue;
-	    wcscpy(wbuffer, findData.cFileName);
-	    *size = wcslen(wbuffer)*2;
-	    return 1;
-	}
-
-	if (GetLastError() == ERROR_NO_MORE_FILES) {
-	    state->errInfo->posix_errno = state->errInfo->os_errno = 0;
-	}
-	else {
-	    set_error(state->errInfo);
-	}
-	FindClose(dir);
-	return 0;
-    }
-}
-
-int
-efile_openfile(Efile_error* errInfo, char* name, int flags, int* pfd, Sint64* pSize)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE1(1, "openfile(%s)", name);
-    call_state_init(&state, errInfo);
-    ret = do_openfile(&state, name, flags, pfd, pSize);
-    call_state_free(&state);
-    return ret;
-}
-
-static
-int do_openfile(Efile_call_state* state,        /* Where to return error codes. */
-	        char* name,			/* Name of directory to open. */
-	        int flags,			/* Flags to use for opening. */
-	        int* pfd,			/* Where to store the file descriptor. */
-	        Sint64* pSize)			/* Where to store the size of the file. */
-{
-    Efile_error* errInfo = state->errInfo;
-    BY_HANDLE_FILE_INFORMATION fileInfo; /* File information from a handle. */
-    HANDLE fd;			/* Handle to open file. */
-    DWORD access;		/* Access mode: GENERIC_READ, GENERIC_WRITE. */
-    DWORD crFlags;
-    DWORD flagsAndAttrs = FILE_ATTRIBUTE_NORMAL;
-    WCHAR *wname = (WCHAR *) name;
-
-    switch (flags & (EFILE_MODE_READ|EFILE_MODE_WRITE)) {
-    case EFILE_MODE_READ:
-	access = GENERIC_READ;
-	crFlags = OPEN_EXISTING;
-	break;
-    case EFILE_MODE_WRITE:
-	access = GENERIC_WRITE;
-	crFlags = CREATE_ALWAYS;
-	break;
-    case EFILE_MODE_READ_WRITE:
-	access = GENERIC_READ|GENERIC_WRITE;
-	crFlags = OPEN_ALWAYS;
-	break;
-    default:
-	errno = EINVAL;
-	check_error(-1, errInfo);
-	return 0;
-    }
-
-    if (flags & EFILE_MODE_SYNC) {
-        flagsAndAttrs = FILE_FLAG_WRITE_THROUGH;
-    }
-
-    if (flags & EFILE_MODE_APPEND) {
-	crFlags = OPEN_ALWAYS;
-    }
-    if (flags & EFILE_MODE_EXCL) {
-	crFlags = CREATE_NEW;
-    }
-    ensure_wpath(state, &wname);
-    fd = CreateFileW(wname, access,
-		    FILE_SHARE_FLAGS,
-		    NULL, crFlags, flagsAndAttrs, NULL);
-
-    /*
-     * Check for errors.
-     */
-
-    if (fd == INVALID_HANDLE_VALUE) {
-	DWORD attr;
-
-	set_error(errInfo);
-
-	/*
-	 * If the error is EACESS, the reason could be that we tried to
-	 * open a directory.  In that case, we'll change the error code
-	 * to EISDIR.
-	 */
-	if (errInfo->posix_errno && 
-	    (attr = GetFileAttributesW(wname)) != INVALID_FILE_ATTRIBUTES && 
-	    (attr & FILE_ATTRIBUTE_DIRECTORY)) {
-	    errInfo->posix_errno = EISDIR;
-	}
-	return 0;
-    }
-
-    /*
-     * Get and return the length of the open file.
-     */
-       
-    if (!GetFileInformationByHandle(fd, &fileInfo))
-	return set_error(errInfo);
-    *pfd = (int) fd;
-    if (pSize) {
-	*pSize = (Sint64)
-	    (((Uint64)fileInfo.nFileSizeHigh << 32) | 
-	     (Uint64)fileInfo.nFileSizeLow);
-    }
-    return 1;
-}
-
-int 
-efile_may_openfile(Efile_error* errInfo, char *name)
-{
-    Efile_call_state state;
-    WCHAR *wname = (WCHAR *) name;
-    DWORD attr;
-    int ret;
-
-    DBG_TRACE(1, name);
-    call_state_init(&state, errInfo);
-    ensure_wpath(&state, &wname);
-    if ((attr = GetFileAttributesW(wname)) == INVALID_FILE_ATTRIBUTES) {
-	errno = ENOENT;
-	ret = check_error(-1, errInfo);
-    }
-    else if (attr & FILE_ATTRIBUTE_DIRECTORY) {
-	errno = EISDIR;
-	ret = check_error(-1, errInfo);
-    }
-    else ret = 1;
-
-    call_state_free(&state);
-    return ret;
-}
-
-void
-efile_closefile(fd)
-int fd;				/* File descriptor for file to close. */
-{
-    DBG_TRACE(2, L"");
-    CloseHandle((HANDLE) fd);
-}
-
-FILE* efile_wfopen(const WCHAR* name, const WCHAR* mode)
-{
-    Efile_call_state state;
-    Efile_error dummy;
-    FILE* f;
-    call_state_init(&state, &dummy);
-    ensure_wpath(&state, (WCHAR**)&name);
-    f = _wfopen(name, mode);
-    call_state_free(&state);
-    return f;
-}
-
-int
-efile_fdatasync(errInfo, fd)
-Efile_error* errInfo;		/* Where to return error codes. */
-int fd;				/* File descriptor for file to sync. */
-{
-    DBG_TRACE(2, L"");
-    /* Not available in Windows, just call regular fsync */
-    return efile_fsync(errInfo, fd);
-}
-
-int
-efile_fsync(errInfo, fd)
-Efile_error* errInfo;		/* Where to return error codes. */
-int fd;				/* File descriptor for file to sync. */
-{
-    DBG_TRACE(2, L"");
-    if (!FlushFileBuffers((HANDLE) fd)) {
-	return check_error(-1, errInfo);
-    }
-    return 1;
-}
-
-int
-efile_fileinfo(Efile_error* errInfo, Efile_info* pInfo,
-	       char* orig_name, int info_for_link)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(1, L"");
-    call_state_init(&state, errInfo);
-    ret = do_fileinfo(&state, pInfo, orig_name, info_for_link);
-    call_state_free(&state);
-    return ret;
-}
-
-static int
-do_fileinfo(Efile_call_state* state, Efile_info* pInfo,
-	    char* orig_name, int info_for_link)
-{
-    Efile_error* errInfo = state->errInfo;
-    HANDLE findhandle;		/* Handle returned by FindFirstFile(). */
-    WIN32_FIND_DATAW findbuf;	/* Data return by FindFirstFile(). */
-    WCHAR* name = NULL;
-    WCHAR* win_path;
-    int name_len;
-    int drive;			/* Drive for filename (1 = A:, 2 = B: etc). */
-    WCHAR *worig_name = (WCHAR *) orig_name;
-
-    ensure_wpath(state, &worig_name);
-    /* Don't allow wildcards to be interpreted by system */
-
-
-    /*
-     * Move the name to a buffer and make sure to remove a trailing
-     * slash, because it causes FindFirstFile() to fail on Win95.
-     */
-
-    name_len = wcslen(worig_name);
-
-    name = wpath_tmp_alloc(state, name_len+1);
-    wcscpy(name, worig_name);
-    if (name_len > 2 && ISSLASH(name[name_len-1]) &&
-	name[name_len-2] != L':') {
-	name[name_len-1] = L'\0';
-    }
-
-    win_path = name;
-    if (wcsncmp(name, L"\\\\?\\", 4) == 0) {
-	win_path += 4;
-    }
-
-    if (wcspbrk(win_path, L"?*")) {
-    enoent:
-	errInfo->posix_errno = ENOENT;
-	errInfo->os_errno = ERROR_FILE_NOT_FOUND;
-        return 0;
-    }
-
-    /* Try to get disk from name.  If none, get current disk.  */
-
-    if (win_path[1] != L':') {
-	WCHAR* cwd_path = get_cwd_wpath_tmp(state);
-        drive = 0;
-	if (cwd_path[1] == L':') {
-	    drive = towlower(cwd_path[0]) - L'a' + 1;
-	}
-    } else if (*win_path && win_path[2] == L'\0') {
-	/*
-	 * X: and nothing more is an error.
-	 */
-	errInfo->posix_errno = ENOENT;
-	errInfo->os_errno = ERROR_FILE_NOT_FOUND;
-	return 0;
-    } else {
-        drive = towlower(*win_path) - L'a' + 1;
-    }
-
-    findhandle = FindFirstFileW(name, &findbuf);
-    if (findhandle == INVALID_HANDLE_VALUE) {
-	WCHAR* path = NULL;
-
-        if (!(wcspbrk(name, L"./\\") &&
-	      (path = get_full_wpath_tmp(state, name, NULL, 0)) &&
-	      /* root dir. ('C:\') or UNC root dir. ('\\server\share\') */
-	      ((wcslen(path) == 3) || is_root_unc_name(path)) &&
-	      (GetDriveTypeW(path) > 1)   ) ) {
-
-	    errInfo->posix_errno = ENOENT;
-	    errInfo->os_errno = ERROR_FILE_NOT_FOUND;
-	    return 0;
-	}
-
-        /*
-         * Root directories (such as C:\ or \\server\share\ are fabricated.
-         */
-	
-        findbuf.dwFileAttributes = FILE_ATTRIBUTE_DIRECTORY;
-        findbuf.nFileSizeHigh = 0;
-        findbuf.nFileSizeLow = 0;
-        findbuf.cFileName[0] = L'\0';
-
-	pInfo->links = 1;
-	pInfo->cTime = pInfo->accessTime = pInfo->modifyTime = 0;
-    } else {
-	SYSTEMTIME SystemTime;
-        FILETIME LocalFTime;
-
-	/*first check if we are a symlink */
-	if (!info_for_link && (findbuf.dwFileAttributes &
-			       FILE_ATTRIBUTE_REPARSE_POINT)){
-	    /*
-	     * given that we know this is a symlink,
-	     we should be able to find its target */
-	    WCHAR* target_name = (WCHAR*) do_readlink(state, (char *) name, NULL, 0);
-	    if (target_name) {
-		FindClose(findhandle);
-		return do_fileinfo(state, pInfo,
-				   (char *) target_name, info_for_link);
-	    }
-	}
-
-	/* number of links: */
-	{
-	    HANDLE handle;	/* Handle returned by CreateFile() */
-	    BY_HANDLE_FILE_INFORMATION fileInfo; /* from  CreateFile() */
-
-            /* We initialise nNumberOfLinks as GetFileInformationByHandle
-               does not always initialise this field */
-            fileInfo.nNumberOfLinks = 1;
-	    if (handle = CreateFileW(name, GENERIC_READ, FILE_SHARE_FLAGS, NULL,
-				    OPEN_EXISTING, 0, NULL)) {
-		GetFileInformationByHandle(handle, &fileInfo);
-		pInfo->links = fileInfo.nNumberOfLinks;
-		CloseHandle(handle);
-	    } else {
-		pInfo->links = 1;
-	    }	
-	}
-
-        FILETIME_TO_EPOCH(pInfo->modifyTime, findbuf.ftLastWriteTime);
-
-        if (findbuf.ftLastAccessTime.dwLowDateTime == 0 &&
-	    findbuf.ftLastAccessTime.dwHighDateTime == 0) {
-	    pInfo->accessTime = pInfo->modifyTime;
-	} else {
-	    FILETIME_TO_EPOCH(pInfo->accessTime, findbuf.ftLastAccessTime);
-	}
-
-        if (findbuf.ftCreationTime.dwLowDateTime == 0 &&
-	    findbuf.ftCreationTime.dwHighDateTime == 0) {
-	    pInfo->cTime = pInfo->modifyTime;
-	} else {
-	    FILETIME_TO_EPOCH(pInfo->cTime ,findbuf.ftCreationTime);
-	}
-        FindClose(findhandle);
-    }
-
-    pInfo->size_low = findbuf.nFileSizeLow;
-    pInfo->size_high = findbuf.nFileSizeHigh;
-	
-    if (info_for_link && (findbuf.dwFileAttributes &
-			  FILE_ATTRIBUTE_REPARSE_POINT))
-	pInfo->type = FT_SYMLINK;
-    else if (findbuf.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-	pInfo->type = FT_DIRECTORY;
-    else
-	pInfo->type = FT_REGULAR;
-
-    if (findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY)
-	pInfo->access = FA_READ;
-    else
-	pInfo->access = FA_READ|FA_WRITE;
-
-    pInfo->mode = dos_to_posix_mode(findbuf.dwFileAttributes, name);
-    pInfo->major_device = drive;
-    pInfo->minor_device = 0;
-    pInfo->inode = 0;
-    pInfo->uid = 0;
-    pInfo->gid = 0;
-    
-    return 1;
-}
-
-int
-efile_write_info(Efile_error* errInfo,
-		 Efile_info* pInfo,
-		 char* name)
-{
-    Efile_call_state state;
-    int ret;
-    call_state_init(&state, errInfo);
-    ret = do_write_info(&state, pInfo, name);
-    call_state_free(&state);
-    return ret;
-}
-
-static int
-do_write_info(Efile_call_state* state,
-              Efile_info* pInfo,
-	      char* name)
-{
-    Efile_error* errInfo = state->errInfo;
-    SYSTEMTIME timebuf;
-    FILETIME ModifyFileTime;
-    FILETIME AccessFileTime;
-    FILETIME CreationFileTime;
-    HANDLE fd;
-    DWORD attr;
-    DWORD tempAttr;
-    WCHAR *wname = (WCHAR *) name;
-
-    DBG_TRACE(1, name);
-
-    ensure_wpath(state, &wname);
-
-    /*
-     * Get the attributes for the file.
-     */
-
-    tempAttr = attr = GetFileAttributesW(wname);
-    if (attr == 0xffffffff) {
-	return set_error(errInfo);
-    }
-    if (pInfo->mode != -1) {
-	if (pInfo->mode & _S_IWRITE) {
-	    /* clear read only bit */
-	    attr &= ~FILE_ATTRIBUTE_READONLY;
-	} else {
-	    /* set read only bit */
-	    attr |= FILE_ATTRIBUTE_READONLY;
-	}
-    }
-
-    /*
-     * Construct all file times.
-     */
-
-    EPOCH_TO_FILETIME(ModifyFileTime,   pInfo->modifyTime);
-    EPOCH_TO_FILETIME(AccessFileTime,   pInfo->accessTime);
-    EPOCH_TO_FILETIME(CreationFileTime, pInfo->cTime);
-
-    /*
-     * If necessary, set the file times.
-     */
-
-    /*
-     * If the has read only access, we must temporarily turn on
-     * write access (this is necessary for native filesystems,
-     * but not for NFS filesystems).
-     */
-
-    if (tempAttr & FILE_ATTRIBUTE_READONLY) {
-	tempAttr &= ~FILE_ATTRIBUTE_READONLY;
-	if (!SetFileAttributesW(wname, tempAttr)) {
-	    return set_error(errInfo);
-	}
-    }
-
-    fd = CreateFileW(wname, GENERIC_READ|GENERIC_WRITE,
-	    FILE_SHARE_FLAGS,
-	    NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
-    if (fd != INVALID_HANDLE_VALUE) {
-	BOOL result = SetFileTime(fd, &CreationFileTime, &AccessFileTime, &ModifyFileTime);
-	if (!result) {
-	    return set_error(errInfo);
-	}
-	CloseHandle(fd);
-    }
-
-    /*
-     * If the file doesn't have the correct attributes, set them now.
-     * (It could have been done before setting the file times, above).
-     */
-
-    if (tempAttr != attr) {
-	if (!SetFileAttributesW(wname, attr)) {
-	    return set_error(errInfo);
-	}
-    }
-    return 1;
-}
-
-
-int
-efile_pwrite(errInfo, fd, buf, count, offset)
-Efile_error* errInfo;		/* Where to return error codes. */
-int fd;				/* File descriptor to write to. */
-char* buf;			/* Buffer to write. */
-size_t count;			/* Number of bytes to write. */
-Sint64 offset;			/* where to write it */
-{
-    int res;
-    DBG_TRACE(2, L"");
-    res = efile_seek(errInfo, fd, offset, EFILE_SEEK_SET, NULL);
-    if (res) {
-	return efile_write(errInfo, EFILE_MODE_WRITE, fd, buf, count);
-    } else {
-	return res;
-    }
-}
-
-/* position and read/write as a single atomic op */
-int
-efile_pread(errInfo, fd, offset, buf, count, pBytesRead)
-Efile_error* errInfo;		/* Where to return error codes. */
-int fd;				/* File descriptor to read from. */
-Sint64 offset;			/* Offset in bytes from BOF. */
-char* buf;			/* Buffer to read into. */
-size_t count;			/* Number of bytes to read. */
-size_t* pBytesRead;		/* Where to return number of bytes read. */
-{
-    int res;
-    DBG_TRACE(2, L"");
-    res = efile_seek(errInfo, fd, offset, EFILE_SEEK_SET, NULL);
-    if (res) {
-	return efile_read(errInfo, EFILE_MODE_READ, fd, buf, count, pBytesRead);
-    } else {
-	return res;
-    }
-}
-
-
-
-int
-efile_write(errInfo, flags, fd, buf, count)
-Efile_error* errInfo;		/* Where to return error codes. */
-int flags;			/* Flags given when file was opened. */
-int fd;				/* File descriptor to write to. */
-char* buf;			/* Buffer to write. */
-size_t count;			/* Number of bytes to write. */
-{
-    DWORD written;		/* Bytes written in last operation. */
-    OVERLAPPED overlapped;
-    OVERLAPPED* pOverlapped = NULL;
-
-    DBG_TRACE(2, L"");
-    if (flags & EFILE_MODE_APPEND) {
-	memset(&overlapped, 0, sizeof(overlapped));
-	overlapped.Offset = 0xffffffff;
-	overlapped.OffsetHigh = 0xffffffff;
-	pOverlapped = &overlapped;
-    }
-    while (count > 0) {
-	if (!WriteFile((HANDLE) fd, buf, count, &written, pOverlapped))
-	    return set_error(errInfo);
-	buf += written;
-	count -= written;
-    }
-    return 1;
-}
-
-int
-efile_writev(Efile_error* errInfo,   /* Where to return error codes */
-	     int flags,              /* Flags given when file was
-				      * opened */
-	     int fd,                 /* File descriptor to write to */
-	     SysIOVec* iov,          /* Vector of buffer structs.
-				      * The structs are unchanged 
-				      * after the call */
-	     int iovcnt)             /* Number of structs in vector */
-{
-    int cnt;                         /* Buffers so far written */
-    OVERLAPPED overlapped;
-    OVERLAPPED* pOverlapped = NULL;
-
-    DBG_TRACE(2, L"");
-    ASSERT(iovcnt >= 0);
-    
-    if (flags & EFILE_MODE_APPEND) {
-	memset(&overlapped, 0, sizeof(overlapped));
-	overlapped.Offset = 0xffffffff;
-	overlapped.OffsetHigh = 0xffffffff;
-	pOverlapped = &overlapped;
-    }
-    for (cnt = 0; cnt < iovcnt; cnt++) {
-	if (iov[cnt].iov_base && iov[cnt].iov_len > 0) {
-	    /* Non-empty buffer */
-	    int p;                   /* Position in buffer */
-	    int w = iov[cnt].iov_len;/* Bytes written in this call */
-	    for (p = 0; p < iov[cnt].iov_len; p += w) {
-		if (!WriteFile((HANDLE) fd, 
-			       iov[cnt].iov_base + p, 
-			       iov[cnt].iov_len - p, 
-			       &w, 
-			       pOverlapped))
-		    return set_error(errInfo);
-	    }
-	}
-    }	
-    return 1;
-}
-
-int
-efile_read(errInfo, flags, fd, buf, count, pBytesRead)
-Efile_error* errInfo;		/* Where to return error codes. */
-int flags;			/* Flags given when file was opened. */
-int fd;				/* File descriptor to read from. */
-char* buf;			/* Buffer to read into. */
-size_t count;			/* Number of bytes to read. */
-size_t* pBytesRead;		/* Where to return number of bytes read. */
-{
-    DWORD nbytes = 0;
-
-    DBG_TRACE(2, L"");
-    if (!ReadFile((HANDLE) fd, buf, count, &nbytes, NULL))
-	return set_error(errInfo);
-
-    *pBytesRead = nbytes;
-    return 1;
-}
-
-int
-efile_seek(errInfo, fd, offset, origin, new_location)
-Efile_error* errInfo;		/* Where to return error codes. */
-int fd;				/* File descriptor to do the seek on. */
-Sint64 offset;			/* Offset in bytes from the given origin. */
-int origin;			/* Origin of seek (SEEK_SET, SEEK_CUR,
-				 * SEEK_END).
-				 */
-Sint64* new_location;		/* Resulting new location in file. */
-{
-    LARGE_INTEGER off, new_loc;
-    
-    DBG_TRACE(2, L"");
-    switch (origin) {
-    case EFILE_SEEK_SET: origin = FILE_BEGIN; break;
-    case EFILE_SEEK_CUR: origin = FILE_CURRENT; break;
-    case EFILE_SEEK_END: origin = FILE_END; break;
-    default:
-	errno = EINVAL;
-	check_error(-1, errInfo);
-	break;
-    }
-    
-    off.QuadPart = offset;
-    if (! SetFilePointerEx((HANDLE) fd, off,
-	new_location ? &new_loc : NULL, origin)) {
-	return set_error(errInfo);
-    }
-    if (new_location) {
-	*new_location = new_loc.QuadPart;
-	DEBUGF(("efile_seek(offset=%ld, origin=%d) -> %ld\n", 
-		(long) offset, origin, (long) *new_location));
-    } else {
-	DEBUGF(("efile_seek(offset=%ld, origin=%d)\n", (long) offset, origin));
-    }
-    return 1;
-}
-
-int
-efile_truncate_file(errInfo, fd, flags)
-Efile_error* errInfo;		/* Where to return error codes. */
-int *fd;				/* File descriptor for file to truncate. */
-int flags;
-{
-    DBG_TRACE(2, L"");
-    if (!SetEndOfFile((HANDLE) (*fd)))
-	return set_error(errInfo);
-    return 1;
-}
-
-
-/*
- * is_root_unc_name - returns TRUE if the argument is a UNC name specifying
- *      a root share.  That is, if it is of the form \\server\share\.
- *      This routine will also return true if the argument is of the
- *      form \\server\share (no trailing slash) but Win32 currently
- *      does not like that form.
- *
- *      Forward slashes ('/') may be used instead of backslashes ('\').
- */
-
-static int
-is_root_unc_name(const WCHAR *path)
-{
-    /*
-     * If a root UNC name, path will start with 2 (but not 3) slashes
-     */
-
-    if ((wcslen(path) >= 5) /* minimum string is "//x/y" */
-	&& ISSLASH(path[0]) && ISSLASH(path[1]))
-    {
-        const WCHAR *p = path + 2;
-
-        /*
-         * find the slash between the server name and share name
-         */
-        while ( * ++ p )
-            if ( ISSLASH(*p) )
-                break ;
-
-        if ( *p && p[1] )
-        {
-            /*
-             * is there a further slash?
-             */
-            while ( * ++ p )
-                if ( ISSLASH(*p) )
-                    break ;
-
-            /*
-             * just final slash (or no final slash)
-             */
-            if ( !*p || !p[1])
-                return 1;
-        }
-    }
-
-    return 0 ;
-}
-
-/*
- * Extracts the root part of an absolute filename (by modifying the string
- * pointed to by the name argument).  The name can start
- * with either a driver letter (for example, C:\), or a UNC name
- * (for example, \\guinness\bjorn).
- *
- * If the name is invalid, the buffer will be modified to point to
- * an empty string.
- *
- * Returns: 1 if the name consists of just the root part, 0 if
- * 	    the name was longer.
- */
-
-static int
-extract_root(WCHAR* name)
-{
-    int len = wcslen(name);
-
-    if (iswalpha(name[0]) && name[1] == L':' && ISSLASH(name[2])) {
-	WCHAR c = name[3];
-	name[3] = L'\0';
-	return c == L'\0';
-    } else if (len < 5 || !ISSLASH(name[0]) || !ISSLASH(name[1])) {
-	goto error;
-    } else {			/* Try to find the end of the UNC name. */
-	WCHAR* p;
-	WCHAR c;
-
-        /*
-         * Find the slash between the server name and share name.
-         */
-
-	for (p = name + 2; *p; p++)
-            if (ISSLASH(*p))
-                break;
-	if (*p == L'\0')
-	    goto error;
-
-	/*
-	 * Find the slash after the share name.
-	 */
-
-	for (p++; *p; p++)
-            if (ISSLASH(*p))
-                break;
-	c = *p;
-	*p = L'\0';
-	return c == L'\0' || p[1] == L'\0';
-    }
-
- error:
-    *name = L'\0';
-    return 1;
-}
-
-static unsigned short
-dos_to_posix_mode(int attr, const WCHAR *name)
-{
-    register unsigned short uxmode;
-    unsigned dosmode;
-    register const WCHAR *p;
-
-    dosmode = attr & 0xff;
-    if ((p = name)[1] == L':')
-	p += 2;
-
-    /* check to see if this is a directory - note we must make a special
-     * check for the root, which DOS thinks is not a directory
-     */
-
-    uxmode = (unsigned short)
-	(((ISSLASH(*p) && !p[1]) || (dosmode & FILE_ATTRIBUTE_DIRECTORY) ||
-	       *p == L'\0') ? _S_IFDIR|_S_IEXEC : _S_IFREG);
-
-    /* If attribute byte does not have read-only bit, it is read-write */
-
-    uxmode |= (dosmode & FILE_ATTRIBUTE_READONLY) ?
-	_S_IREAD : (_S_IREAD|_S_IWRITE);
-
-    /* see if file appears to be executable - check extension of name */
-
-    if (p = wcsrchr(name, L'.')) {
-        if (!_wcsicmp(p, L".exe") ||
-	    !_wcsicmp(p, L".cmd") ||
-	    !_wcsicmp(p, L".bat") ||
-	    !_wcsicmp(p, L".com"))
-            uxmode |= _S_IEXEC;
-    }
-
-    /* propagate user read/write/execute bits to group/other fields */
-
-    uxmode |= (uxmode & 0700) >> 3;
-    uxmode |= (uxmode & 0700) >> 6;
-
-    return uxmode;
-}
-
-
-int
-efile_readlink(Efile_error* errInfo, char* name, char* buffer, size_t size)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(1, name);
-    call_state_init(&state, errInfo);
-    ret = !!do_readlink(&state, name, buffer, size);
-    call_state_free(&state);
-    return ret;
-}
-
-/* If buffer==0, return buffer allocated by wpath_tmp_allocate
-*/
-static char*
-do_readlink(Efile_call_state* state, char* name, char* buffer, size_t size)
-{
-    /*
-     * load dll and see if we have CreateSymbolicLink at runtime:
-     * (Vista only)
-     */
-    HINSTANCE hModule = NULL;
-    WCHAR *wname = (WCHAR *) name;
-    WCHAR *wbuffer = (WCHAR *) buffer;
-    DWORD wsize = size / sizeof(WCHAR);
-    char* ret = NULL;
-
-    if ((hModule = LoadLibrary("kernel32.dll")) != NULL) {
-	typedef DWORD (WINAPI * GETFINALPATHNAMEBYHANDLEPTR)(
-							     HANDLE hFile,
-							     LPCWSTR lpFilePath,
-							     DWORD cchFilePath,
-							     DWORD dwFlags);
-
-	GETFINALPATHNAMEBYHANDLEPTR pGetFinalPathNameByHandle =
-	    (GETFINALPATHNAMEBYHANDLEPTR)GetProcAddress(hModule, "GetFinalPathNameByHandleW");
-
-	if (pGetFinalPathNameByHandle != NULL) {
-	    DWORD fileAttributes;
-	    ensure_wpath(state, &wname);
-	    /* first check if file is a symlink; {error, einval} otherwise */
-	    fileAttributes = GetFileAttributesW(wname);
-	    if ((fileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
-		DWORD success = 0;
-		HANDLE h = CreateFileW(wname, GENERIC_READ, FILE_SHARE_FLAGS, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
-		int len;
-		if(h != INVALID_HANDLE_VALUE) {
-		    if (!wbuffer) { /* dynamic allocation */
-			WCHAR dummy;
-			wsize = pGetFinalPathNameByHandle(h, &dummy, 0, 0);
-			if (wsize) {
-			    wbuffer = wpath_tmp_alloc(state, wsize);
-			}
-		    }
-		    if (wbuffer
-			&& (success = pGetFinalPathNameByHandle(h, wbuffer, wsize, 0))
-			&& success < wsize) {
-			WCHAR* wp;
-
-			/* GetFinalPathNameByHandle prepends path with "\\?\": */
-			len = wcslen(wbuffer);
-			wmemmove(wbuffer,wbuffer+4,len-3);
-			if (len - 4 >= 2 && wbuffer[1] == L':' && wbuffer[0] >= L'A' &&
-			    wbuffer[0] <= L'Z') {
-			    wbuffer[0] = wbuffer[0] + L'a' - L'A';
-			}
-			
-			for (wp=wbuffer ; *wp; wp++)
-			    if (*wp == L'\\')
-				*wp = L'/';
-		    }
-		    CloseHandle(h);
-		}
-		if (success) {
-		    ret = (char*) wbuffer;
-		} else {
-		    set_error(state->errInfo);
-		}
-	    } else {
-		errno = EINVAL;
-		save_last_error(state->errInfo);
-	    }
-	    goto done;
-	}
-    }
-    errno = ENOTSUP;
-    save_last_error(state->errInfo);
-
-done:
-    if (hModule)
-	FreeLibrary(hModule);
-    return ret;
-}
-
-
-int
-efile_altname(Efile_error* errInfo, char* orig_name, char* buffer, size_t size)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE(1, orig_name);
-    call_state_init(&state, errInfo);
-    ret = do_altname(&state, orig_name, buffer, size);
-    call_state_free(&state);
-    return ret;
-}
-
-static int
-do_altname(Efile_call_state* state, char* orig_name, char* buffer, size_t size)
-{
-    WIN32_FIND_DATAW wfd;
-    HANDLE fh;
-    WCHAR* name;
-    int name_len;
-    WCHAR* full_path = NULL;
-    WCHAR *worig_name = (WCHAR *) orig_name;
-    WCHAR *wbuffer = (WCHAR *) buffer;
-    int drive;			/* Drive for filename (1 = A:, 2 = B: etc). */
-
-    /* Don't allow wildcards to be interpreted by system */
-
-    if (wcspbrk(worig_name, L"?*")) {
-    enoent:
-	state->errInfo->posix_errno = ENOENT;
-	state->errInfo->os_errno = ERROR_FILE_NOT_FOUND;
-        return 0;
-    }
-
-    /*
-     * Move the name to a buffer and make sure to remove a trailing
-     * slash, because it causes FindFirstFile() to fail on Win95.
-     */
-    ensure_wpath(state, &worig_name);
-    name_len = wcslen(worig_name);
-
-    name = wpath_tmp_alloc(state, name_len + 1);
-    wcscpy(name, worig_name);
-    if (name_len > 2 && ISSLASH(name[name_len-1]) &&
-	name[name_len-2] != L':') {
-	name[name_len-1] = L'\0';
-    }
-    
-    /* Try to get disk from name.  If none, get current disk.  */
-
-    if (name[1] != L':') {
-	WCHAR* cwd_path = get_cwd_wpath_tmp(state);
-        drive = 0;
-        if (cwd_path[1] == L':') {
-	    drive = towlower(cwd_path[0]) - L'a' + 1;
-	}
-    } else if (*name && name[2] == L'\0') {
-	/*
-	 * X: and nothing more is an error.
-	 */
-	goto enoent;
-    } else {
-        drive = towlower(*name) - L'a' + 1;
-    }
-    fh = FindFirstFileW(name,&wfd);
-    if (fh == INVALID_HANDLE_VALUE) {
-	DWORD fff_error = GetLastError();
-        if (!(wcspbrk(name, L"./\\") &&
-	      (full_path = get_full_wpath_tmp(state, name, NULL, 0)) &&
-	      /* root dir. ('C:\') or UNC root dir. ('\\server\share\') */
-	      ((wcslen(full_path) == 3) || is_root_unc_name(full_path)) &&
-	      (GetDriveTypeW(full_path) > 1)   ) ) {
-
-	    set_os_errno(state->errInfo, fff_error);
-	    return 0;
-	}
-        /*
-         * Root directories (such as C:\ or \\server\share\ are fabricated.
-         */
-	wcscpy(wbuffer,name);
-	return 1;
-    }
-	
-    wcscpy(wbuffer,wfd.cAlternateFileName);
-    if (!*wbuffer) {
-	wcscpy(wbuffer,wfd.cFileName);
-    }
-    FindClose(fh);
-    return 1;
-}
-
-
-int
-efile_link(Efile_error* errInfo, char* old, char* new)
-{
-    Efile_call_state state;
-    WCHAR *wold = (WCHAR *) old;
-    WCHAR *wnew = (WCHAR *) new;
-    int ret;
-    DBG_TRACE(1, old);
-    call_state_init(&state, errInfo);
-    ensure_wpath(&state, &wold);
-    ensure_wpath(&state, &wnew);
-    if(!CreateHardLinkW(wnew, wold, NULL)) {
-	ret = set_error(errInfo);
-    }
-    else ret =1;
-    call_state_free(&state);
-    return ret;
-}
-
-int
-efile_symlink(Efile_error* errInfo, char* old, char* new)
-{
-    Efile_call_state state;
-    int ret;
-    DBG_TRACE2(1, "symlink(%s <- %s)", old, new);
-    call_state_init(&state, errInfo);
-    ret = do_symlink(&state, old, new);
-    call_state_free(&state);
-    return ret;
-}
-
-static int
-do_symlink(Efile_call_state* state, char* old, char* new)
-{
-    /*
-     * Load dll and see if we have CreateSymbolicLink at runtime:
-     * (Vista only)
-     */
-    HINSTANCE hModule = NULL;
-    WCHAR *wold = (WCHAR *) old;
-    WCHAR *wnew = (WCHAR *) new;
-
-    DBG_TRACE(1, old);
-    if ((hModule = LoadLibrary("kernel32.dll")) != NULL) {
-	typedef BOOLEAN (WINAPI  * CREATESYMBOLICLINKFUNCPTR) (
-	     LPCWSTR lpSymlinkFileName,
-	     LPCWSTR lpTargetFileName,
-	     DWORD dwFlags);
-
-	CREATESYMBOLICLINKFUNCPTR pCreateSymbolicLink =
-	    (CREATESYMBOLICLINKFUNCPTR) GetProcAddress(hModule,
-						       "CreateSymbolicLinkW");
-	/* A for MBCS, W for UNICODE... char* above implies 'W'! */
-	if (pCreateSymbolicLink != NULL) {
-	  ensure_wpath(state, &wold);
-	  ensure_wpath(state, &wnew);
-	  {
-	    DWORD attr = GetFileAttributesW(wold);
-	    int flag = (attr != INVALID_FILE_ATTRIBUTES &&
-			attr & FILE_ATTRIBUTE_DIRECTORY) ? 1 : 0;
-	    /*  SYMBOLIC_LINK_FLAG_DIRECTORY = 1 */
-	    BOOLEAN success = pCreateSymbolicLink(wnew, wold, flag);
-	    FreeLibrary(hModule);
-
-	    if (success) {
-		return 1;
-	    } else {
-		return set_error(state->errInfo);
-	    }
-	  }
-	} else
-	    FreeLibrary(hModule);
-    }
-    errno = ENOTSUP;
-    return check_error(-1, state->errInfo);
-}
-
-int
-efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset,
-	    Sint64 length, int advise)
-{
-    DBG_TRACE(2, L"");
-    /* posix_fadvise is not available on Windows, do nothing */
-    errno = ERROR_SUCCESS;
-    return check_error(0, errInfo);
-}
-
-int
-efile_fallocate(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length)
-{
-    DBG_TRACE(2, L"");
-    /* No file preallocation method available in Windows. */
-    errno = errno_map(ERROR_NOT_SUPPORTED);
-    SetLastError(ERROR_NOT_SUPPORTED);
-
-    return check_error(-1, errInfo);
-}