1 /* closexec.c - set or clear the close-on-exec descriptor flag
3 Copyright (C) 1991, 2004, 2005, 2006, 2009 Free Software
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 The code is taken from glibc/manual/llio.texi */
29 /* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
30 or clear the flag if VALUE is false.
31 Return 0 on success, or -1 on error with `errno' set.
33 Note that on MingW, this function does NOT protect DESC from being
34 inherited into spawned children. Instead, either use dup_cloexec
35 followed by closing the original DESC, or use interfaces such as
36 open or pipe2 that accept flags like O_CLOEXEC to create DESC
37 non-inheritable in the first place. */
40 set_cloexec_flag (int desc, bool value)
44 int flags = fcntl (desc, F_GETFD, 0);
48 int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
51 || fcntl (desc, F_SETFD, newflags) != -1)
59 /* Use dup2 to reject invalid file descriptors; the cloexec flag
60 will be unaffected. */
66 if (dup2 (desc, desc) < 0)
67 /* errno is EBADF here. */
70 /* There is nothing we can do on this kind of platform. Punt. */
76 /* Duplicates a file handle FD, while marking the copy to be closed
77 prior to exec or spawn. Returns -1 and sets errno if FD could not
83 return fcntl (fd, F_DUPFD_CLOEXEC, 0);