rdate.c revision 1.16 
1/*	$NetBSD: rdate.c,v 1.16 2005/06/02 09:20:37 lukem Exp $	*/
2
3/*
4 * Copyright (c) 1994 Christos Zoulas
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by Christos Zoulas.
18 * 4. 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, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33/*
34 * rdate.c: Set the date from the specified host
35 *
36 * 	Uses the rfc868 time protocol at socket 37.
37 *	Time is returned as the number of seconds since
38 *	midnight January 1st 1900.
39 */
40#include <sys/cdefs.h>
41#ifndef lint
42__RCSID("$NetBSD: rdate.c,v 1.16 2005/06/02 09:20:37 lukem Exp $");
43#endif /* lint */
44
45#include <sys/types.h>
46#include <sys/socket.h>
47#include <sys/time.h>
48
49#include <netinet/in.h>
50
51#include <ctype.h>
52#include <err.h>
53#include <netdb.h>
54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57#include <unistd.h>
58#include <util.h>
59
60/* seconds from midnight Jan 1900 - 1970 */
61#define DIFFERENCE 2208988800UL
62
63	int	main(int, char **);
64static	void	usage(void);
65
66static void
67usage(void)
68{
69	(void) fprintf(stderr, "usage: %s [-psa] host\n", getprogname());
70	(void) fprintf(stderr, "  -p: just print, don't set\n");
71	(void) fprintf(stderr, "  -s: just set, don't print\n");
72	(void) fprintf(stderr, "  -a: use adjtime instead of instant change\n");
73}
74
75int
76main(int argc, char *argv[])
77{
78	int             pr = 0, silent = 0, s;
79	int		slidetime = 0;
80	int		adjustment;
81	time_t          tim;
82	char           *hname;
83	const char     *emsg = NULL;
84	struct addrinfo	hints, *res, *res0;
85	int             c;
86	int		error;
87
88	adjustment = 0;
89	while ((c = getopt(argc, argv, "psa")) != -1)
90		switch (c) {
91		case 'p':
92			pr++;
93			break;
94
95		case 's':
96			silent++;
97			break;
98
99		case 'a':
100			slidetime++;
101			break;
102
103		default:
104			usage();
105			return 1;
106		}
107
108	if (argc - 1 != optind) {
109		usage();
110		return 1;
111	}
112	hname = argv[optind];
113
114	memset(&hints, 0, sizeof (hints));
115	hints.ai_family = PF_UNSPEC;
116	hints.ai_socktype = SOCK_STREAM;
117	hints.ai_flags = AI_CANONNAME;
118	error = getaddrinfo(hname, "time", &hints, &res0);
119	if (error)
120		errx(1, "%s: %s", gai_strerror(error), hname);
121
122	for (res = res0, s = -1; res != NULL; res = res->ai_next) {
123		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
124		if (s < 0) {
125			emsg = "socket";
126			continue;
127		}
128
129		if (connect(s, res->ai_addr, res->ai_addrlen)) {
130			close(s);
131			s = -1;
132			emsg = "connect";
133			continue;
134		}
135
136		break;
137	}
138	if (s < 0)
139		err(1, "%s", emsg);
140
141	if (read(s, &tim, sizeof(time_t)) != sizeof(time_t))
142		err(1, "Could not read data");
143
144	(void) close(s);
145	tim = ntohl(tim) - DIFFERENCE;
146
147	if (!pr) {
148	    struct timeval  tv;
149	    if (!slidetime) {
150		    logwtmp("|", "date", "");
151		    tv.tv_sec = tim;
152		    tv.tv_usec = 0;
153		    if (settimeofday(&tv, NULL) == -1)
154			    err(1, "Could not set time of day");
155		    logwtmp("{", "date", "");
156	    } else {
157		    struct timeval tv_current;
158		    if (gettimeofday(&tv_current, NULL) == -1)
159			    err(1, "Could not get local time of day");
160		    adjustment = tv.tv_sec = tim - tv_current.tv_sec;
161		    tv.tv_usec = 0;
162		    if (adjtime(&tv, NULL) == -1)
163			    err(1, "Could not adjust time of day");
164	    }
165	}
166
167	if (!silent) {
168		(void) fputs(ctime(&tim), stdout);
169		if (slidetime)
170		    (void) fprintf(stdout,
171				   "%s: adjust local clock by %d seconds\n",
172				   getprogname(), adjustment);
173	}
174	return 0;
175}
176