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      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