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