gl/cloexec.c

   1 /* closexec.c - set or clear the close-on-exec descriptor flag
   2
   3    Copyright (C) 1991, 2004, 2005, 2006 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18
  19    The code is taken from glibc/manual/llio.texi  */
  20
  21 #include <config.h>
  22
  23 #include "cloexec.h"
  24
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27
  28 #ifndef FD_CLOEXEC
  29 # define FD_CLOEXEC 1
  30 #endif
  31
  32 /* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
  33    or clear the flag if VALUE is false.
  34    Return 0 on success, or -1 on error with `errno' set. */
  35
  36 int
  37 set_cloexec_flag (int desc, bool value)
  38 {
  39 #if defined F_GETFD && defined F_SETFD
  40
  41   int flags = fcntl (desc, F_GETFD, 0);
  42
  43   if (0 <= flags)
  44     {
  45       int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
  46
  47       if (flags == newflags
  48           || fcntl (desc, F_SETFD, newflags) != -1)
  49         return 0;
  50     }
  51
  52   return -1;
  53
  54 #else
  55
  56   return 0;
  57
  58 #endif
  59 }