1 /* $NetBSD: adjtime.c,v 1.12 2011/10/15 23:00:02 christos Exp $ */
2
3 /*
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Emmanuel Dreyfus.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <sys/cdefs.h>
35 #if defined(LIBC_SCCS) && !defined(lint)
36 __RCSID("$NetBSD: adjtime.c,v 1.12 2011/10/15 23:00:02 christos Exp $");
37 #endif /* LIBC_SCCS and not lint */
38
39 #include "namespace.h"
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <paths.h>
43 #include <unistd.h>
44 #include <time.h>
45 #include <string.h>
46 #include <sys/types.h>
47 #include <sys/ioctl.h>
48 #include <sys/syscall.h>
49
50 #include <sys/clockctl.h>
51
52 extern int __clockctl_fd;
53
54 int ____adjtime50(const struct timeval *, struct timeval *);
55
56 int
adjtime(const struct timeval * delta,struct timeval * olddelta)57 adjtime(const struct timeval *delta, struct timeval *olddelta)
58 {
59 struct clockctl_adjtime args;
60 int rv;
61
62 /*
63 * we always attempt the syscall first and switch to
64 * clockctl if that fails with EPERM
65 */
66 if (__clockctl_fd == -1) {
67 rv = ____adjtime50(delta, olddelta);
68
69 /*
70 * try via clockctl if the call fails with EPERM
71 */
72 if (rv != -1 || errno != EPERM)
73 return rv;
74
75 /*
76 * If this fails, it means that we are not root
77 * and we cannot open clockctl. This is a failure.
78 */
79 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY | O_CLOEXEC, 0);
80 if (__clockctl_fd == -1) {
81 /* original error was EPERM - don't leak open errors */
82 errno = EPERM;
83 return -1;
84 }
85 }
86
87 /*
88 * If __clockctl_fd >=0, clockctl has already been open
89 * and used, so we carry on using it.
90 */
91 args.delta = delta;
92 args.olddelta = olddelta;
93 return ioctl(__clockctl_fd, CLOCKCTL_ADJTIME, &args);
94 }
95