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
37 static int
openat(int fd,const char * path,int flags,...)38 openat(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