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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | /* vi: set sw=4 ts=4: */ /* * The Rdate command will ask a time server for the RFC 868 time * and optionally set the system time. * * by Sterling Huxley <sterling@europa.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <sys/time.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> #include <getopt.h> #include <string.h> #include <time.h> #include <stdlib.h> #include <unistd.h> #include "busybox.h" static const int RFC_868_BIAS = 2208988800UL; static time_t askremotedate(const char *host) { struct hostent *h; struct sockaddr_in s_in; struct servent *tserv; unsigned long int nett, localt; int fd; h = xgethostbyname(host); /* get the IP addr */ memcpy(&s_in.sin_addr, h->h_addr, sizeof(s_in.sin_addr)); s_in.sin_port = htons(37); /* find port # */ if ((tserv = getservbyname("time", "tcp")) != NULL) s_in.sin_port = tserv->s_port; s_in.sin_family = AF_INET; if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) /* get net connection */ perror_msg_and_die("socket"); if (connect(fd, (struct sockaddr *)&s_in, sizeof(s_in)) < 0) /* connect to time server */ perror_msg_and_die("%s", host); if (read(fd, (void *)&nett, 4) != 4) /* read time from server */ error_msg_and_die("%s did not send the complete time", host); close(fd); /* convert from network byte order to local byte order. * RFC 868 time is the number of seconds * since 00:00 (midnight) 1 January 1900 GMT * the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT * Subtract the RFC 868 time to get Linux epoch */ localt= ntohl(nett) - RFC_868_BIAS; return(localt); } int rdate_main(int argc, char **argv) { time_t remote_time; int opt; int setdate = 1; int printdate = 1; /* Interpret command line args */ while ((opt = getopt(argc, argv, "sp")) > 0) { switch (opt) { case 's': printdate = 0; setdate = 1; break; case 'p': printdate = 1; setdate = 0; break; default: show_usage(); } } if (optind == argc) show_usage(); remote_time = askremotedate(argv[optind]); if (setdate) { if (stime(&remote_time) < 0) perror_msg_and_die("Could not set time of day"); } if (printdate) printf("%s", ctime(&remote_time)); return EXIT_SUCCESS; } |