1/*-
2 * Copyright (c) 2012 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Pawel Jakub Dawidek under sponsorship from
6 * the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef	_OPENAT_H_
31#define	_OPENAT_H_
32
33#include <fcntl.h>
34#include <stdarg.h>
35#include <unistd.h>
36
37static int
38openat(int fd, const char *path, int flags, ...)
39{
40	int cfd, ffd, error;
41
42	cfd = open(".", O_RDONLY | O_DIRECTORY);
43	if (cfd == -1)
44		return (-1);
45
46	if (fchdir(fd) == -1) {
47		error = errno;
48		(void)close(cfd);
49		errno = error;
50		return (-1);
51	}
52
53	if ((flags & O_CREAT) != 0) {
54		va_list ap;
55		int mode;
56
57		va_start(ap, flags);
58		mode = va_arg(ap, int);
59		va_end(ap);
60
61		ffd = open(path, flags, mode);
62	} else {
63		ffd = open(path, flags);
64	}
65
66	error = errno;
67	(void)fchdir(cfd);
68	(void)close(cfd);
69	errno = error;
70	return (ffd);
71}
72
73#endif	/* !_OPENAT_H_ */
74