mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-22 07:09:54 +00:00
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/* cloexec.c - set or clear the close-on-exec descriptor flag
|
|
|
|
Copyright (C) 1991, 2004-2006, 2009-2024 Free Software Foundation, Inc.
|
|
|
|
This file is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This file 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 Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
/* The code is taken from glibc/manual/llio.texi */
|
|
|
|
#include <config.h>
|
|
|
|
#include "cloexec.h"
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
|
|
/* Set the 'FD_CLOEXEC' flag of DESC if VALUE is true,
|
|
or clear the flag if VALUE is false.
|
|
Return 0 on success, or -1 on error with 'errno' set.
|
|
|
|
Note that on MingW, this function does NOT protect DESC from being
|
|
inherited into spawned children. Instead, either use dup_cloexec
|
|
followed by closing the original DESC, or use interfaces such as
|
|
open or pipe2 that accept flags like O_CLOEXEC to create DESC
|
|
non-inheritable in the first place. */
|
|
|
|
int
|
|
set_cloexec_flag (int desc, bool value)
|
|
{
|
|
#ifdef F_SETFD
|
|
|
|
int flags = fcntl (desc, F_GETFD, 0);
|
|
|
|
if (0 <= flags)
|
|
{
|
|
int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
|
|
|
|
if (flags == newflags
|
|
|| fcntl (desc, F_SETFD, newflags) != -1)
|
|
return 0;
|
|
}
|
|
|
|
return -1;
|
|
|
|
#else /* !F_SETFD */
|
|
|
|
/* Use dup2 to reject invalid file descriptors; the cloexec flag
|
|
will be unaffected. */
|
|
if (desc < 0)
|
|
{
|
|
errno = EBADF;
|
|
return -1;
|
|
}
|
|
if (dup2 (desc, desc) < 0)
|
|
/* errno is EBADF here. */
|
|
return -1;
|
|
|
|
/* There is nothing we can do on this kind of platform. Punt. */
|
|
return 0;
|
|
#endif /* !F_SETFD */
|
|
}
|
|
|
|
|
|
/* Duplicates a file handle FD, while marking the copy to be closed
|
|
prior to exec or spawn. Returns -1 and sets errno if FD could not
|
|
be duplicated. */
|
|
|
|
int
|
|
dup_cloexec (int fd)
|
|
{
|
|
return fcntl (fd, F_DUPFD_CLOEXEC, 0);
|
|
}
|