usr/src/cmd/cmd-inet/usr.bin/rdate.c

   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 }