/* closexec.c - set or clear the close-on-exec descriptor flag
- Copyright (C) 1991, 2004 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ Copyright (C) 1991, 2004-2006, 2009-2010 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
The code is taken from glibc/manual/llio.texi */
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
+#include <config.h>
#include "cloexec.h"
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-
+#include <errno.h>
#include <fcntl.h>
-
-#ifndef FD_CLOEXEC
-# define FD_CLOEXEC 1
-#endif
+#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. */
+ 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)
{
-#if defined F_GETFD && defined F_SETFD
+#ifdef F_SETFD
int flags = fcntl (desc, F_GETFD, 0);
int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
if (flags == newflags
- || fcntl (desc, F_SETFD, newflags) != -1)
- return 0;
+ || fcntl (desc, F_SETFD, newflags) != -1)
+ return 0;
}
return -1;
-#else
+#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 */
+}
+
-#endif
+/* 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);
}