This is the downport of

Bug#24509 - 2048 file descriptor limit on windows needs increasing, also 
WL#3049 - improved Windows I/O
                        
The patch replaces the use of the POSIX I/O interfaces in mysys on Windows with 
the Win32 API calls (CreateFile, WriteFile, etc). The Windows HANDLE for the open 
file is stored in the my_file_info struct, along with a flag for append mode 
because the Windows API does not support opening files in append mode in all cases)
The default max open files has been increased to 16384 and can be increased further
by setting --max-open-files=<value> during the server start.
                              
Another major change in this patch that almost all Windows specific file IO code
has been moved to a new file my_winfile.c, greatly reducing the amount of code 
in #ifdef blocks within mysys, thus improving readability.
                               
                                    
Minor enhancements:
- my_(f)stat() is changed to use __stati64 structure with  64 file size
and timestamps. It will return correct file size now (C runtime implementation
used to report outdated information)
- my_lock on Windows is prepared to handle additional timeout parameter
- after review : changed __WIN__ to _WIN32 in the new and changed code.

client/mysqlbinlog.cc:
  fileno -> my_fileno
client/readline.cc:
  fileno -> my_fileno
include/config-win.h:
  Increase OS_FILE_LIMIT for Windows.
  Remove O_SHARE - Windows does not support it. Its definition conflicts with
  O_SHORT_LIVED, that has different semantics.
include/my_dir.h:
  Use stat64 for stat() family of functions on Windows, because of 64 bit file size.
include/my_global.h:
  Increased default value for open file limit to 16K
include/my_sys.h:
  - my_file_info got new structure members - file handle and open flags
  - 2 new Windows-only mysys functions : my_get_osfhandle and my_osmaperr,
    modelled after Windows C runtime functions _get_osfhandle and _dosmaperr
libmysql/CMakeLists.txt:
  new files my_winfile.c and my_winerr.c
mysql-test/suite/large_tests/r/lock_tables_big.result:
  test for more then 2048 open file descriptors on Windows
mysql-test/suite/large_tests/t/lock_tables_big.test:
  test for more then 2048 open file descriptors on Windows
mysys/CMakeLists.txt:
  new files my_winfile.c and my_winerr.c
mysys/Makefile.am:
  new files my_winfile.c and my_winerr.c
mysys/default_modify.c:
  fileno -> my_fileno
mysys/my_chsize.c:
  implementation of chsize on Windows now moved to my_winfile.c
mysys/my_create.c:
  - my_sopen->my_win_open
  - close open file before removing (won't generally work on Windows otherwise)
mysys/my_file.c:
  On Windows, files returned by my_open will not start with 0, but 2048 
  (making it simple to detect incompatible mix of CRT and mysys  io functions)
mysys/my_fopen.c:
  fileno->my_win_fileno , fclose->my_win_fclose, fdopen->my_win_fdopen
  Check for legal filename is done by my_win_[f]open functions
mysys/my_fstream.c:
  fileno->my_fileno
mysys/my_lib.c:
  Windows stat() functions are moved to my_winfile.c
mysys/my_lock.c:
  Move Windows code under #ifdef to a separate function win_lock().
  Add a parameter for lock wait timeout
mysys/my_mmap.c:
   _get_osfhandle->my_get_osfhandle
mysys/my_open.c:
  my_sopen->my_win_open (simpler interface)
mysys/my_pread.c:
  moved most windows specific code to my_win_file.c
  Use my_win_pread
mysys/my_quick.c:
  Use my_win_read/my_win_write
mysys/my_read.c:
  Moved most of windows specific code to my_win_file.c
  Use my_win_read()
mysys/my_seek.c:
  On Windows, use my_win_lseek() in my_seek()/my_tell()
  Removed dead code (synchronization of lseeks)
  Improved DBUG tracing (file position is ulonglong, not ulong)
mysys/my_static.c:
  Removed array initialization. my_file_info_default is global variable
  thus it is initialized with all zeros anyway
mysys/my_sync.c:
  _commit->my_win_fsync
mysys/my_winerr.c:
  New file my_winerr.c
  Exports my_osmaperr modelled after undocumented C runtime
  function _dosmaperr(). The problem with _dosmaperr() used previously is that 
  1) it is nowhere documented and thus code relying on it is not guaranteed to work
     in subsequent releases on the C runtime
  2) it is present only in static C runtime (mysqld does not link if compiled with
    /MD)
mysys/my_winfile.c:
  New file my_winfile.c
  Implements ANSI/Posix file IO routines, when possible using native Windows IO, without
  C runtime (C runtime dropped because of the 2048 file descriptor limit).
mysys/my_write.c:
  write->my_win_write
mysys/mysys_priv.h:
  Declaration of Windows Posix functions (private to mysys, shall not be visible
  outside)
storage/innobase/handler/ha_innodb.cc:
  mysys native Windows IO : correct innodb tmp file handling
  mysql_tmpfile does not return valid CRT file descriptor, thus
  it is not possible to dup() it. Instead, the native file handle has 
  to be duplicated and then converted to CRT descriptor.
storage/myisam/mi_locking.c:
  _commit->my_sync

1 files changed, 671 insertions, 0 deletions

diff --git a/mysys/my_winfile.c b/mysys/my_winfile.c
new file mode 100644
index 00000000000..de1d747c967
--- /dev/null
+++ b/mysys/my_winfile.c
@@ -0,0 +1,671 @@
+/* Copyright (C) 2008 MySQL AB
+
+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; version 2 of the License.
+
+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, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+/*
+  The purpose of this file is to provide implementation of file IO routines on 
+  Windows that can be thought as drop-in replacement for corresponding C runtime
+  functionality.
+
+  Compared to Windows CRT, this one 
+  - does not have the same file descriptor 
+  limitation (default is 16384 and can  be increased further, whereas CRT poses
+  a hard limit of 2048 file descriptors)
+  - the file operations are not serialized
+  - positional IO pread/pwrite is ported here.
+  - no text mode for files, all IO is "binary"
+
+  Naming convention:
+  All routines are prefixed with my_win_, e.g Posix open() is implemented with 
+  my_win_open()
+
+  Implemented are
+  - POSIX routines(e.g open, read, lseek ...)
+  - Some ANSI C stream routines (fopen, fdopen, fileno, fclose)
+  - Windows CRT equvalients (my_get_osfhandle, open_osfhandle)
+
+  Worth to note:
+  - File descriptors used here are located in a range that is not compatible 
+  with CRT on purpose. Attempt to use a file descriptor from Windows CRT library
+  range in my_win_* function will be punished with DBUG_ASSERT()
+
+  - File streams (FILE *) are actually from the C runtime. The routines provided
+  here are useful only in scernarios that use low-level IO with my_win_fileno()
+*/
+
+#ifdef _WIN32
+
+#include "mysys_priv.h"
+#include <share.h>
+#include <sys/stat.h>
+
+/* Associates a file descriptor with an existing operating-system file handle.*/
+File my_open_osfhandle(HANDLE handle, int oflag)
+{
+  int offset= -1;
+  uint i;
+  DBUG_ENTER("my_open_osfhandle");
+
+  pthread_mutex_lock(&THR_LOCK_open);
+  for(i= MY_FILE_MIN; i < my_file_limit;i++)
+  {
+    if(my_file_info[i].fhandle == 0)
+    {
+      struct st_my_file_info *finfo= &(my_file_info[i]);
+      finfo->type=    FILE_BY_OPEN;
+      finfo->fhandle= handle;
+      finfo->oflag=   oflag;
+      offset= i;
+      break;
+    }
+  }
+  pthread_mutex_unlock(&THR_LOCK_open);
+  if(offset == -1)
+    errno= EMFILE; /* to many file handles open */
+  DBUG_RETURN(offset);
+}
+
+
+static void invalidate_fd(File fd)
+{
+  DBUG_ENTER("invalidate_fd");
+  DBUG_ASSERT(fd >= MY_FILE_MIN && fd < (int)my_file_limit);
+  my_file_info[fd].fhandle= 0;
+  DBUG_VOID_RETURN;
+}
+
+
+/* Get Windows handle for a file descriptor */
+HANDLE my_get_osfhandle(File fd)
+{
+  DBUG_ENTER("my_get_osfhandle");
+  DBUG_ASSERT(fd >= MY_FILE_MIN && fd < (int)my_file_limit);
+  DBUG_RETURN(my_file_info[fd].fhandle);
+}
+
+
+static int my_get_open_flags(File fd)
+{
+  DBUG_ENTER("my_get_osfhandle");
+  DBUG_ASSERT(fd >= MY_FILE_MIN && fd < (int)my_file_limit);
+  DBUG_RETURN(my_file_info[fd].oflag);
+}
+
+
+/*
+  Open a file with sharing. Similar to _sopen() from libc, but allows managing
+  share delete on win32
+
+  SYNOPSIS
+  my_win_sopen()
+  path    file name
+  oflag   operation flags
+  shflag  share flag
+  pmode   permission flags
+
+  RETURN VALUE
+  File descriptor of opened file if success
+  -1 and sets errno if fails.
+*/
+
+File my_win_sopen(const char *path, int oflag, int shflag, int pmode)
+{
+  int  fh;                                /* handle of opened file */
+  int mask;
+  HANDLE osfh;                            /* OS handle of opened file */
+  DWORD fileaccess;                       /* OS file access (requested) */
+  DWORD fileshare;                        /* OS file sharing mode */
+  DWORD filecreate;                       /* OS method of opening/creating */
+  DWORD fileattrib;                       /* OS file attribute flags */
+  SECURITY_ATTRIBUTES SecurityAttributes;
+
+  DBUG_ENTER("my_win_sopen");
+
+  if (check_if_legal_filename(path))
+  {
+    errno= EACCES;
+    DBUG_RETURN(-1);
+  }
+  SecurityAttributes.nLength= sizeof(SecurityAttributes);
+  SecurityAttributes.lpSecurityDescriptor= NULL;
+  SecurityAttributes.bInheritHandle= !(oflag & _O_NOINHERIT);
+
+  /* decode the access flags  */
+  switch (oflag & (_O_RDONLY | _O_WRONLY | _O_RDWR)) {
+    case _O_RDONLY:         /* read access */
+      fileaccess= GENERIC_READ;
+      break;
+    case _O_WRONLY:         /* write access */
+      fileaccess= GENERIC_WRITE;
+      break;
+    case _O_RDWR:           /* read and write access */
+      fileaccess= GENERIC_READ | GENERIC_WRITE;
+      break;
+    default:                /* error, bad oflag */
+      errno= EINVAL;
+      DBUG_RETURN(-1);
+  }
+
+  /* decode sharing flags */
+  switch (shflag) {
+    case _SH_DENYRW:        /* exclusive access except delete */
+      fileshare= FILE_SHARE_DELETE;
+      break;
+    case _SH_DENYWR:        /* share read and delete access */
+      fileshare= FILE_SHARE_READ | FILE_SHARE_DELETE;
+      break;
+    case _SH_DENYRD:        /* share write and delete access */
+      fileshare= FILE_SHARE_WRITE | FILE_SHARE_DELETE;
+      break;
+    case _SH_DENYNO:        /* share read, write and delete access */
+      fileshare= FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
+      break;
+    case _SH_DENYRWD:       /* exclusive access */
+      fileshare= 0L;
+      break;
+    case _SH_DENYWRD:       /* share read access */
+      fileshare= FILE_SHARE_READ;
+      break;
+    case _SH_DENYRDD:       /* share write access */
+      fileshare= FILE_SHARE_WRITE;
+      break;
+    case _SH_DENYDEL:       /* share read and write access */
+      fileshare= FILE_SHARE_READ | FILE_SHARE_WRITE;
+      break;
+    default:                /* error, bad shflag */
+      errno= EINVAL;
+      DBUG_RETURN(-1);
+  }
+
+  /* decode open/create method flags  */
+  switch (oflag & (_O_CREAT | _O_EXCL | _O_TRUNC)) {
+    case 0:
+    case _O_EXCL:                   /* ignore EXCL w/o CREAT */
+      filecreate= OPEN_EXISTING;
+      break;
+
+    case _O_CREAT:
+      filecreate= OPEN_ALWAYS;
+      break;
+
+    case _O_CREAT | _O_EXCL:
+    case _O_CREAT | _O_TRUNC | _O_EXCL:
+      filecreate= CREATE_NEW;
+      break;
+
+    case _O_TRUNC:
+    case _O_TRUNC | _O_EXCL:        /* ignore EXCL w/o CREAT */
+      filecreate= TRUNCATE_EXISTING;
+      break;
+
+    case _O_CREAT | _O_TRUNC:
+      filecreate= CREATE_ALWAYS;
+      break;
+
+    default:
+      /* this can't happen ... all cases are covered */
+      errno= EINVAL;
+      DBUG_RETURN(-1);
+  }
+
+  /* decode file attribute flags if _O_CREAT was specified */
+  fileattrib= FILE_ATTRIBUTE_NORMAL;     /* default */
+  if (oflag & _O_CREAT) 
+  {
+    _umask((mask= _umask(0)));
+
+    if (!((pmode & ~mask) & _S_IWRITE))
+      fileattrib= FILE_ATTRIBUTE_READONLY;
+  }
+
+  /* Set temporary file (delete-on-close) attribute if requested. */
+  if (oflag & _O_TEMPORARY) 
+  {
+    fileattrib|= FILE_FLAG_DELETE_ON_CLOSE;
+    fileaccess|= DELETE;
+  }
+
+  /* Set temporary file (delay-flush-to-disk) attribute if requested.*/
+  if (oflag & _O_SHORT_LIVED)
+    fileattrib|= FILE_ATTRIBUTE_TEMPORARY;
+
+  /* Set sequential or random access attribute if requested. */
+  if (oflag & _O_SEQUENTIAL)
+    fileattrib|= FILE_FLAG_SEQUENTIAL_SCAN;
+  else if (oflag & _O_RANDOM)
+    fileattrib|= FILE_FLAG_RANDOM_ACCESS;
+
+  /* try to open/create the file  */
+  if ((osfh= CreateFile(path, fileaccess, fileshare, &SecurityAttributes, 
+    filecreate, fileattrib, NULL)) == INVALID_HANDLE_VALUE)
+  {
+    /*
+       OS call to open/create file failed! map the error, release
+       the lock, and return -1. note that it's not necessary to
+       call _free_osfhnd (it hasn't been used yet).
+    */
+    my_osmaperr(GetLastError());     /* map error */
+    DBUG_RETURN(-1);                 /* return error to caller */
+  }
+
+  if ((fh= my_open_osfhandle(osfh, 
+    oflag & (_O_APPEND | _O_RDONLY | _O_TEXT))) == -1)
+  {
+    CloseHandle(osfh);
+  }
+
+  DBUG_RETURN(fh);                   /* return handle */
+}
+
+
+File my_win_open(const char *path, int flags)
+{
+  DBUG_ENTER("my_win_open");
+  DBUG_RETURN(my_win_sopen((char *) path, flags | _O_BINARY, _SH_DENYNO, 
+    _S_IREAD | S_IWRITE));
+}
+
+
+int my_win_close(File fd)
+{
+  DBUG_ENTER("my_win_close");
+  if(CloseHandle(my_get_osfhandle(fd)))
+  {
+    invalidate_fd(fd);
+    DBUG_RETURN(0);
+  }
+  my_osmaperr(GetLastError());
+  DBUG_RETURN(-1);
+}
+
+
+size_t my_win_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset)
+{
+  DWORD         nBytesRead;
+  HANDLE        hFile;
+  OVERLAPPED    ov= {0};
+  LARGE_INTEGER li;
+
+  DBUG_ENTER("my_win_pread");
+
+  if(!Count)
+    DBUG_RETURN(0);
+#ifdef _WIN64
+  if(Count > UINT_MAX)
+    Count= UINT_MAX;
+#endif
+
+  hFile=         (HANDLE)my_get_osfhandle(Filedes);
+  li.QuadPart=   offset;
+  ov.Offset=     li.LowPart;
+  ov.OffsetHigh= li.HighPart;
+
+  if(!ReadFile(hFile, Buffer, (DWORD)Count, &nBytesRead, &ov))
+  {
+    DWORD lastError= GetLastError();
+    /*

+      ERROR_BROKEN_PIPE is returned when no more data coming

+      through e.g. a command pipe in windows : see MSDN on ReadFile.

+    */

+    if(lastError == ERROR_HANDLE_EOF || lastError == ERROR_BROKEN_PIPE)
+      DBUG_RETURN(0); /*return 0 at EOF*/
+    my_osmaperr(lastError);
+    DBUG_RETURN(-1);
+  }
+  DBUG_RETURN(nBytesRead);
+}
+
+
+size_t my_win_read(File Filedes, uchar *Buffer, size_t Count)
+{
+  DWORD         nBytesRead;
+  HANDLE        hFile;
+
+  DBUG_ENTER("my_win_read");
+  if(!Count)
+    DBUG_RETURN(0);
+#ifdef _WIN64
+  if(Count > UINT_MAX)
+    Count= UINT_MAX;
+#endif
+
+  hFile= (HANDLE)my_get_osfhandle(Filedes);
+
+  if(!ReadFile(hFile, Buffer, (DWORD)Count, &nBytesRead, NULL))
+  {
+    DWORD lastError= GetLastError();
+    /*
+      ERROR_BROKEN_PIPE is returned when no more data coming
+      through e.g. a command pipe in windows : see MSDN on ReadFile.
+    */
+    if(lastError == ERROR_HANDLE_EOF || lastError == ERROR_BROKEN_PIPE)
+      DBUG_RETURN(0); /*return 0 at EOF*/
+    my_osmaperr(lastError);
+    DBUG_RETURN(-1);
+  }
+  DBUG_RETURN(nBytesRead);
+}
+
+
+size_t my_win_pwrite(File Filedes, const uchar *Buffer, size_t Count, 
+                     my_off_t offset)
+{
+  DWORD         nBytesWritten;
+  HANDLE        hFile;
+  OVERLAPPED    ov= {0};
+  LARGE_INTEGER li;
+
+  DBUG_ENTER("my_win_pwrite");
+  DBUG_PRINT("my",("Filedes: %d, Buffer: %p, Count: %zd, offset: %llu", 
+    Filedes, Buffer, Count, (ulonglong)offset));
+
+  if(!Count)
+    DBUG_RETURN(0);
+
+#ifdef _WIN64
+  if(Count > UINT_MAX)
+    Count= UINT_MAX;
+#endif
+
+  hFile=         (HANDLE)my_get_osfhandle(Filedes);
+  li.QuadPart=   offset;
+  ov.Offset=     li.LowPart;
+  ov.OffsetHigh= li.HighPart;
+
+  if(!WriteFile(hFile, Buffer, (DWORD)Count, &nBytesWritten, &ov))
+  {
+    my_osmaperr(GetLastError());
+    DBUG_RETURN(-1);
+  }
+  else
+    DBUG_RETURN(nBytesWritten);
+}
+
+
+my_off_t my_win_lseek(File fd, my_off_t pos, int whence)
+{
+  LARGE_INTEGER offset;
+  LARGE_INTEGER newpos;
+
+  DBUG_ENTER("my_win_lseek");
+
+  /* Check compatibility of Windows and Posix seek constants */
+  compile_time_assert(FILE_BEGIN == SEEK_SET && FILE_CURRENT == SEEK_CUR 
+    && FILE_END == SEEK_END);
+
+  offset.QuadPart= pos;
+  if(!SetFilePointerEx(my_get_osfhandle(fd), offset, &newpos, whence))
+  {
+    my_osmaperr(GetLastError());
+    newpos.QuadPart= -1;
+  }
+  DBUG_RETURN(newpos.QuadPart);
+}
+
+
+#ifndef FILE_WRITE_TO_END_OF_FILE
+#define FILE_WRITE_TO_END_OF_FILE       0xffffffff
+#endif
+size_t my_win_write(File fd, const uchar *Buffer, size_t Count)
+{
+  DWORD nWritten;
+  OVERLAPPED ov;
+  OVERLAPPED *pov= NULL;
+  HANDLE hFile;
+
+  DBUG_ENTER("my_win_write");
+  DBUG_PRINT("my",("Filedes: %d, Buffer: %p, Count %zd", fd, Buffer, Count));
+  if(my_get_open_flags(fd) & _O_APPEND)
+  {
+    /*
+       Atomic append to the end of file is is done by special initialization of 
+       the OVERLAPPED structure. See MSDN WriteFile documentation for more info.
+    */
+    memset(&ov, 0, sizeof(ov));
+    ov.Offset= FILE_WRITE_TO_END_OF_FILE; 
+    ov.OffsetHigh= -1;
+    pov= &ov;
+  }
+
+  hFile= my_get_osfhandle(fd);
+  if(!WriteFile(hFile, Buffer, (DWORD)Count, &nWritten, pov))
+  {
+    nWritten= (size_t)-1;
+    my_osmaperr(GetLastError());
+  }
+  DBUG_RETURN((size_t)nWritten);
+}
+
+
+int my_win_chsize(File fd,  my_off_t newlength)
+{
+  HANDLE hFile;
+  LARGE_INTEGER length;
+  DBUG_ENTER("my_win_chsize");
+
+  hFile= (HANDLE) my_get_osfhandle(fd);
+  length.QuadPart= newlength;
+  if (!SetFilePointerEx(hFile, length , NULL , FILE_BEGIN))
+    goto err;
+  if (!SetEndOfFile(hFile))
+    goto err;
+  DBUG_RETURN(0);
+err:
+  my_osmaperr(GetLastError());
+  my_errno= errno;
+  DBUG_RETURN(-1);
+}
+
+
+/* Get the file descriptor for stdin,stdout or stderr */
+static File my_get_stdfile_descriptor(FILE *stream)
+{
+  HANDLE hFile;
+  DWORD nStdHandle;
+  DBUG_ENTER("my_get_stdfile_descriptor");
+
+  if(stream == stdin)
+    nStdHandle= STD_INPUT_HANDLE;
+  else if(stream == stdout)
+    nStdHandle= STD_OUTPUT_HANDLE;
+  else if(stream == stderr)
+    nStdHandle= STD_ERROR_HANDLE;
+  else
+    DBUG_RETURN(-1);
+
+  hFile= GetStdHandle(nStdHandle);
+  if(hFile != INVALID_HANDLE_VALUE)
+    DBUG_RETURN(my_open_osfhandle(hFile, 0));
+  DBUG_RETURN(-1);
+}
+
+
+File my_win_fileno(FILE *file)
+{
+  HANDLE hFile= (HANDLE)_get_osfhandle(fileno(file));
+  int retval= -1;
+  uint i;
+
+  DBUG_ENTER("my_win_fileno");
+
+  for(i= MY_FILE_MIN; i < my_file_limit; i++)
+  {
+    if(my_file_info[i].fhandle == hFile)
+    {
+      retval= i;
+      break;
+    }
+  }
+  if(retval == -1)
+    /* try std stream */
+    DBUG_RETURN(my_get_stdfile_descriptor(file));
+  DBUG_RETURN(retval);
+}
+
+
+FILE *my_win_fopen(const char *filename, const char *type)
+{
+  FILE *file;
+  int flags= 0;
+  DBUG_ENTER("my_win_open");
+
+  /* 
+    If we are not creating, then we need to use my_access to make sure  
+    the file exists since Windows doesn't handle files like "com1.sym" 
+    very  well
+  */
+  if (check_if_legal_filename(filename))
+  {
+    errno= EACCES;
+    DBUG_RETURN(NULL);
+  }
+
+  file= fopen(filename, type);
+  if(!file)
+    DBUG_RETURN(NULL);
+
+  if(strchr(type,'a') != NULL)
+    flags= O_APPEND;
+
+  /*
+     Register file handle in my_table_info.
+     Necessary for my_fileno()
+   */
+  if(my_open_osfhandle((HANDLE)_get_osfhandle(fileno(file)), flags) < 0)
+  {
+    fclose(file);
+    DBUG_RETURN(NULL);
+  }
+  DBUG_RETURN(file);
+}
+
+
+FILE * my_win_fdopen(File fd, const char *type)
+{
+  FILE *file;
+  int crt_fd;
+  int flags= 0;
+
+  DBUG_ENTER("my_win_fdopen");
+
+  if(strchr(type,'a') != NULL)
+    flags= O_APPEND;
+  /* Convert OS file handle to CRT file descriptor and then call fdopen*/
+  crt_fd= _open_osfhandle((intptr_t)my_get_osfhandle(fd), flags);
+  if(crt_fd < 0)
+    file= NULL;
+  else
+    file= fdopen(crt_fd, type);
+  DBUG_RETURN(file);
+}
+
+
+int my_win_fclose(FILE *file)
+{
+  File fd;
+
+  DBUG_ENTER("my_win_close");
+  fd= my_fileno(file);
+  if(fd < 0)
+    DBUG_RETURN(-1);
+  if(fclose(file) < 0)
+    DBUG_RETURN(-1);
+  invalidate_fd(fd);
+  DBUG_RETURN(0);
+}
+
+
+
+/*
+  Quick and dirty my_fstat() implementation for Windows.
+  Use CRT fstat on temporarily allocated file descriptor.
+  Patch file size, because size that fstat returns is not 
+  reliable (may be outdated)
+*/
+int my_win_fstat(File fd, struct _stati64 *buf)
+{
+  int crt_fd;
+  int retval;
+  HANDLE hFile, hDup;
+
+  DBUG_ENTER("my_win_fstat");
+
+  hFile= my_get_osfhandle(fd);
+  if(!DuplicateHandle( GetCurrentProcess(), hFile, GetCurrentProcess(), 
+    &hDup ,0,FALSE,DUPLICATE_SAME_ACCESS))
+  {
+    my_osmaperr(GetLastError());
+    DBUG_RETURN(-1);
+  }
+  if ((crt_fd= _open_osfhandle((intptr_t)hDup,0)) < 0)
+    DBUG_RETURN(-1);
+
+  retval= _fstati64(crt_fd, buf);
+  if(retval == 0)
+  {
+    /* File size returned by stat is not accurate (may be outdated), fix it*/
+    GetFileSizeEx(hDup, (PLARGE_INTEGER) (&(buf->st_size)));
+  }
+  _close(crt_fd);
+  DBUG_RETURN(retval);
+}
+
+
+
+int my_win_stat( const char *path, struct _stati64 *buf)
+{
+  DBUG_ENTER("my_win_stat");
+  if(_stati64( path, buf) == 0)
+  {
+    /* File size returned by stat is not accurate (may be outdated), fix it*/
+    WIN32_FILE_ATTRIBUTE_DATA data;
+    if (GetFileAttributesEx(path, GetFileExInfoStandard, &data))
+    {
+      LARGE_INTEGER li;
+      li.LowPart=    data.nFileSizeLow;
+      li.HighPart=   data.nFileSizeHigh;
+      buf->st_size= li.QuadPart;
+    }
+    DBUG_RETURN(0);
+  }
+  DBUG_RETURN(-1);
+}
+
+
+
+int my_win_fsync(File fd)
+{
+  DBUG_ENTER("my_win_fsync");
+  if(FlushFileBuffers(my_get_osfhandle(fd)))
+    DBUG_RETURN(0);
+  my_osmaperr(GetLastError());
+  DBUG_RETURN(-1);
+}
+
+
+
+int my_win_dup(File fd)
+{
+  HANDLE hDup;
+  DBUG_ENTER("my_win_dup");
+  if (DuplicateHandle(GetCurrentProcess(), my_get_osfhandle(fd),
+       GetCurrentProcess(), &hDup, 0, FALSE, DUPLICATE_SAME_ACCESS))
+  {
+     DBUG_RETURN(my_open_osfhandle(hDup, my_get_open_flags(fd)));
+  }
+  my_osmaperr(GetLastError());
+  DBUG_RETURN(-1);
+}
+
+#endif /*_WIN32*/