1 /* closexec.c - set or clear the close-on-exec descriptor flag
3 Copyright (C) 1991, 2004-2006, 2009-2015 Free Software Foundation, Inc.
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.
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.
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/>.
18 The code is taken from glibc/manual/llio.texi */
28 /* Set the 'FD_CLOEXEC' flag of DESC if VALUE is true,
29 or clear the flag if VALUE is false.
30 Return 0 on success, or -1 on error with 'errno' set.
32 Note that on MingW, this function does NOT protect DESC from being
33 inherited into spawned children. Instead, either use dup_cloexec
34 followed by closing the original DESC, or use interfaces such as
35 open or pipe2 that accept flags like O_CLOEXEC to create DESC
36 non-inheritable in the first place. */
39 set_cloexec_flag (int desc
, bool value
)
43 int flags
= fcntl (desc
, F_GETFD
, 0);
47 int newflags
= (value
? flags
| FD_CLOEXEC
: flags
& ~FD_CLOEXEC
);
50 || fcntl (desc
, F_SETFD
, newflags
) != -1)
58 /* Use dup2 to reject invalid file descriptors; the cloexec flag
59 will be unaffected. */
65 if (dup2 (desc
, desc
) < 0)
66 /* errno is EBADF here. */
69 /* There is nothing we can do on this kind of platform. Punt. */
75 /* Duplicates a file handle FD, while marking the copy to be closed
76 prior to exec or spawn. Returns -1 and sets errno if FD could not
82 return fcntl (fd
, F_DUPFD_CLOEXEC
, 0);