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 3 of the License, or
   8    (at your option) 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, see <http://www.gnu.org/licenses/>.
  17
  18    The code is taken from glibc/manual/llio.texi  */
  19
  20 #include <config.h>
  21
  22 #include "cloexec.h"
  23
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26
  27 #ifndef FD_CLOEXEC
  28 # define FD_CLOEXEC 1
  29 #endif
  30
  31 /* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
  32    or clear the flag if VALUE is false.
  33    Return 0 on success, or -1 on error with `errno' set. */
  34
  35 int
  36 set_cloexec_flag (int desc, bool value)
  37 {
  38 #if defined F_GETFD && defined F_SETFD
  39
  40   int flags = fcntl (desc, F_GETFD, 0);
  41
  42   if (0 <= flags)
  43     {
  44       int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
  45
  46       if (flags == newflags
  47           || fcntl (desc, F_SETFD, newflags) != -1)
  48         return 0;
  49     }
  50
  51   return -1;
  52
  53 #else
  54
  55   return 0;
  56
  57 #endif
  58 }