nagios-plugins/lib/cloexec.c

/* closexec.c - set or clear the close-on-exec descriptor flag
   Copyright (C) 1991, 2004 Free Software Foundation, Inc.

   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; either version 2, or (at your option)
   any later version.

   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 code is taken from glibc/manual/llio.texi  */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include "cloexec.h"

#if HAVE_UNISTD_H
# include <unistd.h>
#endif

#if HAVE_FCNTL_H
# include <fcntl.h>
#endif

#ifndef FD_CLOEXEC
# define FD_CLOEXEC 1
#endif

/* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
   or clear the flag if VALUE is false.
   Return true on success, or false on error with `errno' set. */

bool
set_cloexec_flag (int desc, bool value)
{
#if defined F_GETFD && defined F_SETFD

  int flags = fcntl (desc, F_GETFD, 0);
  int newflags;

  if (flags < 0)
    return false;

  newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);

  return (flags == newflags
	  || fcntl (desc, F_SETFD, newflags) != -1);

#else

  return true;

#endif
}