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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2025-01-09 15:50:21 +00:00
emacs/lib/cloexec.c
Paul Eggert 68a256c892 Update from Gnulib
Make the following changes by hand, and run 'admin/merge-gnulib'.
* .gitignore: Add lib/malloc/*.gl.h.
* admin/merge-gnulib: Copy lib/af_alg.h and lib/save-cwd.h
directly from Gnulib, without worrying about Gnulib modules,
as these files are special cases.
(AVOIDED_MODULES): Remove malloc-posix.
* lib/malloc.c, lib/realloc.c, m4/malloc.m4, m4/realloc.m4:
* m4/year2038.m4: New files, copied from Gnulib.
* lib/malloca.c, lib/malloca.h:
* m4/close-stream.m4, m4/glibc21.m4, m4/malloca.m4:
Remove.  These are either no longer present in Gnulib, or are no
longer needed by modules that Emacs uses.
* oldXMenu/AddPane.c, oldXmenu/Addsel.c: Include XmenuInt.h first;
needed for new Gnulib.
* src/xmenu.c: Call emacs_abort, not abort.
2021-10-04 15:21:31 -07:00

84 lines
2.3 KiB
C

/* cloexec.c - set or clear the close-on-exec descriptor flag
Copyright (C) 1991, 2004-2006, 2009-2021 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);
}