Date: Sun, 8 Mar 1998 14:44:04 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: DJ Delorie <dj AT delorie DOT com>
cc: djgpp-workers AT delorie DOT com
Subject: mkstemp made safer
Message-ID: <Pine.SUN.3.91.980308144250.22686i-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk

Here's a change in `mkstemp' analogous to the change in `tmpfile'.

*** src/libc/compat/stdio/mkstemp.c~0	Sun Jun  4 07:04:24 1995
--- src/libc/compat/stdio/mkstemp.c	Fri Mar  6 20:00:08 1998
***************
*** 1,15 ****
  /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
  #include <stdio.h>
  #include <fcntl.h>
  #include <errno.h>
  
  int
  mkstemp (char *_template)
  {
!   if (mktemp (_template))
!     return creat (_template, 0666);
!   else {
      errno = ENOENT;
!     return -1;
!   }
  }
--- 1,25 ----
+ /* Copyright (C) 1998 DJ Delorie, see COPYING.DJ for details */
  /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
  #include <stdio.h>
  #include <fcntl.h>
  #include <errno.h>
+ #include <io.h>
  
  int
  mkstemp (char *_template)
  {
!   char tmp_name[FILENAME_MAX];
!   int  fd = -1;
! 
!   /* Make sure we create a non-exisiting file, even
!      if race conditions exist with other processes.  */
!   do
!     strcpy(tmp_name, _template);
!   while (mktemp (tmp_name) != NULL
! 	 && (fd = _creatnew(tmp_name, 0, SH_DENYRW)) == -1);
! 
!   if (fd == -1)
      errno = ENOENT;
! 
!   return fd;
  }
*** src/libc/compat/stdio/mkstemp.t~0	Sun Jul 23 09:46:40 1995
--- src/libc/compat/stdio/mkstemp.txh	Fri Mar  6 20:02:22 1998
***************
*** 12,18 ****
  @var{template} is a file specification that ends with six trailing
  @code{X} characters.  This function replaces the @code{XXXXXX} with a
  set of characters such that the resulting file name names a nonexisting
! file.  It then creates and opens the file. 
  
  Note that since MS-DOS is limited to eight characters for the file name,
  and since none of the @code{X}'s get replaced by a dot, you can only
--- 12,19 ----
  @var{template} is a file specification that ends with six trailing
  @code{X} characters.  This function replaces the @code{XXXXXX} with a
  set of characters such that the resulting file name names a nonexisting
! file.  It then creates and opens the file in a way which guarantees that
! no other process can access this file.
  
  Note that since MS-DOS is limited to eight characters for the file name,
  and since none of the @code{X}'s get replaced by a dot, you can only
*** src/docs/kb/wc202.t~5	Fri Mar  6 19:37:42 1998
--- src/docs/kb/wc202.txi	Fri Mar  6 20:07:06 1998
***************
*** 346,348 ****
--- 346,353 ----
  though the named file already existed (created by another process).
  This window is now closed.
  @findex open
+ 
+ @code{mkstemp} now makes sure the file it creates is unique even if
+ other processes can create files in the same directory, and opens the
+ file in DENY_ALL mode.
+ @findex mkstemp