1/*-
2 * Copyright (c) 2013 The FreeBSD Foundation
3 * Copyright (c) 2015 Mariusz Zaborski <oshogbo@FreeBSD.org>
4 * All rights reserved.
5 *
6 * This software was developed by Pawel Jakub Dawidek under sponsorship from
7 * the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD: stable/11/lib/libcasper/libcasper/libcasper_impl.c 370017 2021-06-18 09:44:42Z git2svn $
31 */
32
33#include <err.h>
34#include <errno.h>
35#include <fcntl.h>
36#include <paths.h>
37#include <stdlib.h>
38#include <unistd.h>
39
40#include "libcasper_impl.h"
41
42bool
43fd_is_valid(int fd)
44{
45
46	return (fcntl(fd, F_GETFL) != -1 || errno != EBADF);
47}
48
49void
50fd_fix_environment(int *fdp)
51{
52	int nullfd, nfd;
53
54	if (*fdp > STDERR_FILENO)
55		return;
56
57	nullfd = open(_PATH_DEVNULL, O_RDWR);
58	if (nullfd == -1)
59		errx(1, "Unable to open %s", _PATH_DEVNULL);
60
61	while (*fdp <= STDERR_FILENO) {
62		nfd = dup(*fdp);
63		if (nfd == -1)
64			errx(1, "Unable to secure fd");
65		if (dup2(nullfd, *fdp) == -1)
66			errx(1, "Unable to secure fd");
67		*fdp = nfd;
68	}
69
70	close(nullfd);
71}
72
73