xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/rdate.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 #pragma ident	"%Z%%M%	%I%	%E% SMI"
41 
42 /*
43  *  rdate - get date from remote machine
44  *
45  *	sets time, obtaining value from host
46  *	on the tcp/time socket.
47  */
48 
49 #include <signal.h>
50 #include <sys/types.h>
51 #include <sys/time.h>
52 #include <sys/socket.h>
53 #include <netinet/tcp.h>
54 #include <strings.h>
55 #include <unistd.h>
56 #include <stdlib.h>
57 #include <netdb.h>
58 #include <stdio.h>
59 
60 /*
61  * The timeserver returns with time of day in seconds since
62  * Jan 1, 1900. We must subtract 86400(365*70 + 17) to get time
63  * since Jan 1, 1970, which is what get/settimeofday uses.
64  */
65 
66 #define	TOFFSET	((unsigned int)86400*(365*70 + 17))
67 
68 /*
69  * Before setting the system time, the value returned by the
70  * timeserver is checked for plausibility. If the returned date
71  * is before the time this program was written it cannot be
72  * correct.
73  */
74 
75 #define	WRITTEN 440199955		/* 22:45:55 13/Dec/1983 */
76 #define	SECONDS_TO_MS	1000
77 
78 static void timeout(int);
79 
80 int
81 main(int argc, char **argv)
82 {
83 	int s, i;
84 	uint32_t time;
85 	struct timeval timestruct;
86 	unsigned int connect_timeout;
87 	/* number of seconds to wait for something to happen. */
88 	unsigned int rdate_timeout = 30;	/* seconds */
89 	struct addrinfo hints;
90 	struct addrinfo *res;
91 	int rc;
92 
93 	if (argc != 2) {
94 		(void) fputs("usage: rdate host\n", stderr);
95 		exit(EXIT_FAILURE);
96 	}
97 
98 	(void) memset(&hints, 0, sizeof (hints));
99 	hints.ai_protocol = IPPROTO_TCP;
100 	res = NULL;
101 
102 	/*
103 	 * getaddrinfo() may take a long time, because it can involve
104 	 * NIS, DNS, or LDAP lookups. Set an alarm timer. Note that this
105 	 * may still fail, depending on how SIGALRM is handled by the
106 	 * functions invoked by getaddrinfo().
107 	 */
108 
109 	(void) signal(SIGALRM, timeout);
110 	(void) alarm(rdate_timeout);
111 
112 	/*
113 	 * Note: memory not freed due to short lifetime of program.
114 	 */
115 
116 	rc = getaddrinfo(argv[1], "time", &hints, &res);
117 	(void) alarm(0);
118 
119 	if (rc != 0) {
120 		(void) fprintf(stderr, "Host name %s not found: %s\n", argv[1],
121 		    gai_strerror(rc));
122 		exit(EXIT_FAILURE);
123 	}
124 
125 	connect_timeout = rdate_timeout * SECONDS_TO_MS;
126 	for (; res != NULL; res = res->ai_next) {
127 		s = socket(res->ai_addr->sa_family, res->ai_socktype,
128 		    res->ai_protocol);
129 		if (s < 0) {
130 			perror("rdate: socket");
131 			exit(EXIT_FAILURE);
132 		}
133 
134 		if (setsockopt(s, IPPROTO_TCP, TCP_CONN_ABORT_THRESHOLD,
135 		    (char *)&connect_timeout, sizeof (connect_timeout)) == -1) {
136 			perror("setsockopt TCP_CONN_ABORT_THRESHOLD");
137 		}
138 
139 		if (connect(s, res->ai_addr, res->ai_addrlen) >= 0)
140 			break;
141 
142 		if (res->ai_next == NULL) {
143 			perror("rdate: connect");
144 			(void) close(s);
145 			exit(EXIT_FAILURE);
146 		}
147 
148 		(void) close(s);
149 	}
150 
151 	(void) alarm(rdate_timeout);
152 	if (read(s, (char *)&time, sizeof (time)) != sizeof (time)) {
153 		perror("rdate: read");
154 		exit(EXIT_FAILURE);
155 	}
156 	(void) alarm(0);
157 
158 	time = ntohl(time) - TOFFSET;
159 	/* date must be later than when program was written */
160 	if (time < WRITTEN) {
161 		(void) fprintf(stderr, "didn't get plausible time from %s\n",
162 		    argv[1]);
163 		exit(EXIT_FAILURE);
164 	}
165 	timestruct.tv_usec = 0;
166 	timestruct.tv_sec = time;
167 	i = settimeofday(&timestruct, 0);
168 	if (i == -1) {
169 		perror("couldn't set time of day");
170 		exit(EXIT_FAILURE);
171 	} else {
172 		(void) printf("%s", ctime(&timestruct.tv_sec));
173 #if defined(i386)
174 		(void) system("/usr/sbin/rtc -c > /dev/null 2>&1");
175 #endif
176 	}
177 	return (EXIT_SUCCESS);
178 }
179 
180 /*ARGSUSED*/
181 static void
182 timeout(int sig)
183 {
184 	(void) fputs("couldn't contact time server\n", stderr);
185 	exit(EXIT_FAILURE);
186 	/* NOTREACHED */
187 }
188