xref: /netbsd-src/lib/libc/sys/clock_settime.c (revision 27578b9aac214cc7796ead81dcc5427e79d5f2a0)
1 /*	$NetBSD: clock_settime.c,v 1.2 2001/09/17 23:32:33 thorpej 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 "namespace.h"
35 
36 #include <sys/types.h>
37 #include <sys/ioctl.h>
38 #include <sys/syscall.h>
39 
40 #include <fcntl.h>
41 #include <paths.h>
42 #include <string.h>
43 #include <time.h>
44 #include <unistd.h>
45 
46 #include <sys/clockctl.h>
47 
48 #ifdef __weak_alias
49 __weak_alias(clock_settime,_clock_settime)
50 #endif
51 
52 int
53 clock_settime(clock_id, tp)
54 	clockid_t clock_id;
55 	const struct timespec *tp;
56 {
57 	struct clockctl_clock_settime_args args;
58 	int error;
59 	int fd;
60 	quad_t q;
61 	int rv;
62 
63 	/*
64 	 * Root always uses the settimeofday syscall
65 	 */
66 	if (geteuid() == 0)
67 		goto try_syscall;
68 
69 	/*
70 	 * Try to use /dev/clockctl, and revert to
71 	 * settimeofday syscall if it fails.
72 	 */
73 	fd = open(_PATH_CLOCKCTL, O_WRONLY, 0);
74 	if (fd == -1)
75 		goto try_syscall;
76 
77 	args.clock_id = clock_id;
78 	(void)memcpy (&args.tp, tp, sizeof(tp));
79 	error = ioctl(fd, CLOCKCTL_CLOCK_SETTIME, &args);
80 	(void)close(fd);
81 	if (!error)
82 		return 0;
83 
84 try_syscall:
85 	q = __syscall((quad_t)SYS_clock_settime, clock_id, tp);
86 	if (/* LINTED constant */ sizeof (quad_t) == sizeof (register_t) ||
87 		 /* LINTED constant */ BYTE_ORDER == LITTLE_ENDIAN)
88 		rv = (int)q;
89 	else
90 		rv = (int)((u_quad_t)q >> 32);
91 	return rv;
92 }
93