Backport Fix for Bug#24509 - 2048 file descriptor limit on windows needs increasing.

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.

Noteworthy benefit of this patch is that it removes limits from the table_cache size - 
allowing for more simultaneus users

1 files changed, 8 insertions, 219 deletions

diff --git a/mysys/my_open.c b/mysys/my_open.c
index fe7f65c450b..b1788506832 100644
--- a/mysys/my_open.c
+++ b/mysys/my_open.c
@@ -17,9 +17,7 @@
 #include "mysys_err.h"
 #include <my_dir.h>
 #include <errno.h>
-#if defined(__WIN__)
-#include <share.h>
-#endif
+
 
 /*
   Open a file
@@ -43,29 +41,8 @@ File my_open(const char *FileName, int Flags, myf MyFlags)
   DBUG_ENTER("my_open");
   DBUG_PRINT("my",("Name: '%s'  Flags: %d  MyFlags: %d",
 		   FileName, Flags, MyFlags));
-#if defined(__WIN__)
-  /* 
-    Check that we don't try to open or create a file name that may
-    cause problems for us in the future (like PRN)
-  */  
-  if (check_if_legal_filename(FileName))
-  {
-    errno= EACCES;
-    DBUG_RETURN(my_register_filename(-1, FileName, FILE_BY_OPEN,
-                                     EE_FILENOTFOUND, MyFlags));
-  }
-#ifndef __WIN__
-  if (Flags & O_SHARE)
-    fd = sopen((char *) FileName, (Flags & ~O_SHARE) | O_BINARY, SH_DENYNO,
-	       MY_S_IREAD | MY_S_IWRITE);
-  else
-    fd = open((char *) FileName, Flags | O_BINARY,
-	      MY_S_IREAD | MY_S_IWRITE);
-#else
-  fd= my_sopen((char *) FileName, (Flags & ~O_SHARE) | O_BINARY, SH_DENYNO,
-	       MY_S_IREAD | MY_S_IWRITE);
-#endif
-
+#if defined(_WIN32)
+  fd= my_win_open(FileName, Flags);
 #elif !defined(NO_OPEN_3)
   fd = open(FileName, Flags, my_umask);	/* Normal unix */
 #else
@@ -94,11 +71,14 @@ int my_close(File fd, myf MyFlags)
   DBUG_PRINT("my",("fd: %d  MyFlags: %d",fd, MyFlags));
 
   pthread_mutex_lock(&THR_LOCK_open);
+#ifndef _WIN32
   do
   {
     err= close(fd);
   } while (err == -1 && errno == EINTR);
-
+#else
+  err= my_win_close(fd);
+#endif
   if (err)
   {
     DBUG_PRINT("error",("Got error %d on close",err));
@@ -109,9 +89,6 @@ int my_close(File fd, myf MyFlags)
   if ((uint) fd < my_file_limit && my_file_info[fd].type != UNOPEN)
   {
     my_free(my_file_info[fd].name, MYF(0));
-#if defined(THREAD) && !defined(HAVE_PREAD)
-    pthread_mutex_destroy(&my_file_info[fd].mutex);
-#endif
     my_file_info[fd].type = UNOPEN;
   }
   my_file_opened--;
@@ -141,16 +118,12 @@ File my_register_filename(File fd, const char *FileName, enum file_type
 			  type_of_file, uint error_message_number, myf MyFlags)
 {
   DBUG_ENTER("my_register_filename");
-  if ((int) fd >= 0)
+  if ((int) fd >= MY_FILE_MIN)
   {
     if ((uint) fd >= my_file_limit)
     {
-#if defined(THREAD) && !defined(HAVE_PREAD)
-      my_errno= EMFILE;
-#else
       thread_safe_increment(my_file_opened,&THR_LOCK_open);
       DBUG_RETURN(fd);				/* safeguard */
-#endif
     }
     else
     {
@@ -160,9 +133,6 @@ File my_register_filename(File fd, const char *FileName, enum file_type
         my_file_opened++;
         my_file_total_opened++;
         my_file_info[fd].type = type_of_file;
-#if defined(THREAD) && !defined(HAVE_PREAD)
-        pthread_mutex_init(&my_file_info[fd].mutex,MY_MUTEX_INIT_FAST);
-#endif
         pthread_mutex_unlock(&THR_LOCK_open);
         DBUG_PRINT("exit",("fd: %d",fd));
         DBUG_RETURN(fd);
@@ -187,188 +157,7 @@ File my_register_filename(File fd, const char *FileName, enum file_type
   DBUG_RETURN(-1);
 }
 
-#ifdef __WIN__
-
-extern void __cdecl _dosmaperr(unsigned long);
-
-/*
-  Open a file with sharing. Similar to _sopen() from libc, but allows managing
-  share delete on win32
-
-  SYNOPSIS
-    my_sopen()
-      path    fully qualified 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_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;
-
-  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;
-      _doserrno= 0L;        /* not an OS error */
-      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;
-      _doserrno= 0L;        /* not an OS error */
-      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;
-      _doserrno= 0L;
-      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).
-     */
-    _dosmaperr(GetLastError());     /* map error */
-    return -1;                      /* return error to caller */
-  }
-
-  if ((fh= _open_osfhandle((intptr_t)osfh, 
-                           oflag & (_O_APPEND | _O_RDONLY | _O_TEXT))) == -1)
-  {
-    _dosmaperr(GetLastError());     /* map error */
-    CloseHandle(osfh);
-  }
-
-  return fh;                        /* return handle */
-}
-#endif /* __WIN__ */
 
 
 #ifdef EXTRA_DEBUG