lib/cloexec.c

   1 /* closexec.c - set or clear the close-on-exec descriptor flag
   2    Copyright (C) 1991, 2004 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17
  18    The code is taken from glibc/manual/llio.texi  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include "cloexec.h"
  25
  26 #if HAVE_UNISTD_H
  27 # include <unistd.h>
  28 #endif
  29
  30 #if HAVE_FCNTL_H
  31 # include <fcntl.h>
  32 #endif
  33
  34 #ifndef FD_CLOEXEC
  35 # define FD_CLOEXEC 1
  36 #endif
  37
  38 /* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
  39    or clear the flag if VALUE is false.
  40    Return 0 on success, or -1 on error with `errno' set. */
  41
  42 int
  43 set_cloexec_flag (int desc, bool value)
  44 {
  45 #if defined F_GETFD && defined F_SETFD
  46
  47   int flags = fcntl (desc, F_GETFD, 0);
  48
  49   if (0 <= flags)
  50     {
  51       int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
  52
  53       if (flags == newflags
  54           || fcntl (desc, F_SETFD, newflags) != -1)
  55         return 0;
  56     }
  57
  58   return -1;
  59
  60 #else
  61
  62   return 0;
  63
  64 #endif
  65 }