| /* 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> |
| * |
| * Licensed under GPL v2 or later, see file License for details. |
| */ |
| |
| #include "libbb.h" |
| |
| enum { RFC_868_BIAS = 2208988800UL }; |
| |
| static void socket_timeout(int sig) |
| { |
| bb_error_msg_and_die("timeout connecting to time server"); |
| } |
| |
| static time_t askremotedate(const char *host) |
| { |
| uint32_t nett; |
| int fd; |
| |
| /* Add a timeout for dead or inaccessible servers */ |
| alarm(10); |
| signal(SIGALRM, socket_timeout); |
| |
| fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37)); |
| |
| if (safe_read(fd, (void *)&nett, 4) != 4) /* read time from server */ |
| bb_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 |
| */ |
| |
| return ntohl(nett) - RFC_868_BIAS; |
| } |
| |
| int rdate_main(int argc, char **argv); |
| int rdate_main(int argc, char **argv) |
| { |
| time_t remote_time; |
| unsigned long flags; |
| |
| opt_complementary = "-1"; |
| flags = getopt32(argc, argv, "sp"); |
| |
| remote_time = askremotedate(argv[optind]); |
| |
| if ((flags & 2) == 0) { |
| time_t current_time; |
| |
| time(¤t_time); |
| if (current_time == remote_time) |
| bb_error_msg("current time matches remote time"); |
| else |
| if (stime(&remote_time) < 0) |
| bb_perror_msg_and_die("cannot set time of day"); |
| } |
| |
| if ((flags & 1) == 0) |
| printf("%s", ctime(&remote_time)); |
| |
| return EXIT_SUCCESS; |
| } |