rdate.c revision 1.20 
1/*	$NetBSD: rdate.c,v 1.20 2017/05/04 16:26:09 sevan 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28/*
29 * rdate.c: Set the date from the specified host
30 *
31 * 	Uses the rfc868 time protocol at socket 37.
32 *	Time is returned as the number of seconds since
33 *	midnight January 1st 1900.
34 */
35#include <sys/cdefs.h>
36#ifndef lint
37__RCSID("$NetBSD: rdate.c,v 1.20 2017/05/04 16:26:09 sevan Exp $");
38#endif /* lint */
39
40#include <sys/types.h>
41#include <sys/socket.h>
42#include <sys/time.h>
43
44#include <netinet/in.h>
45
46#include <err.h>
47#include <netdb.h>
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#include <unistd.h>
52#include <util.h>
53
54/* seconds from midnight Jan 1900 - 1970 */
55#define DIFFERENCE 2208988800ULL
56
57static	void	usage(void);
58
59static void
60usage(void)
61{
62	(void) fprintf(stderr, "usage: %s [-psa] host\n", getprogname());
63	(void) fprintf(stderr, "  -p: just print, don't set\n");
64	(void) fprintf(stderr, "  -s: just set, don't print\n");
65	(void) fprintf(stderr, "  -a: use adjtime instead of instant change\n");
66}
67
68int
69main(int argc, char *argv[])
70{
71	int             pr = 0, silent = 0, s;
72	int		slidetime = 0;
73	int		adjustment;
74	uint32_t	data;
75	time_t          tim;
76	char           *hname;
77	const char     *emsg = NULL;
78	struct addrinfo	hints, *res, *res0;
79	int             c;
80	int		error;
81
82	adjustment = 0;
83	while ((c = getopt(argc, argv, "psa")) != -1)
84		switch (c) {
85		case 'p':
86			pr++;
87			break;
88
89		case 's':
90			silent++;
91			break;
92
93		case 'a':
94			slidetime++;
95			break;
96
97		default:
98			usage();
99			return 1;
100		}
101
102	if (argc - 1 != optind) {
103		usage();
104		return 1;
105	}
106	hname = argv[optind];
107
108	memset(&hints, 0, sizeof (hints));
109	hints.ai_family = PF_UNSPEC;
110	hints.ai_socktype = SOCK_STREAM;
111	hints.ai_flags = AI_CANONNAME;
112	error = getaddrinfo(hname, "time", &hints, &res0);
113	if (error)
114		errx(1, "%s: %s", gai_strerror(error), hname);
115
116	for (res = res0, s = -1; res != NULL; res = res->ai_next) {
117		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
118		if (s < 0) {
119			emsg = "socket";
120			continue;
121		}
122
123		if (connect(s, res->ai_addr, res->ai_addrlen)) {
124			close(s);
125			s = -1;
126			emsg = "connect";
127			continue;
128		}
129
130		break;
131	}
132	if (s < 0)
133		err(1, "%s", emsg);
134
135	if (read(s, &data, sizeof(uint32_t)) != sizeof(uint32_t))
136		err(1, "Could not read data");
137
138	(void) close(s);
139	tim = ntohl(data) - DIFFERENCE;
140
141	if (!pr) {
142	    struct timeval  tv;
143	    if (!slidetime) {
144		    logwtmp("|", "date", "");
145		    tv.tv_sec = tim;
146		    tv.tv_usec = 0;
147		    if (settimeofday(&tv, NULL) == -1)
148			    err(1, "Could not set time of day");
149		    logwtmp("{", "date", "");
150	    } else {
151		    struct timeval tv_current;
152		    if (gettimeofday(&tv_current, NULL) == -1)
153			    err(1, "Could not get local time of day");
154		    adjustment = tv.tv_sec = tim - tv_current.tv_sec;
155		    tv.tv_usec = 0;
156		    if (adjtime(&tv, NULL) == -1)
157			    err(1, "Could not adjust time of day");
158	    }
159	}
160
161	if (!silent) {
162		(void) fputs(ctime(&tim), stdout);
163		if (slidetime)
164		    (void) fprintf(stdout,
165				   "%s: adjust local clock by %d seconds\n",
166				   getprogname(), adjustment);
167	}
168	return 0;
169}
170