[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * The Rdate command will ask a time server for the RFC 868 time
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| 4 | * and optionally set the system time.
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| 5 | *
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| 6 | * by Sterling Huxley <sterling@europa.com>
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| 7 | *
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| 8 | * Licensed under GPL v2 or later, see file License for details.
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| 9 | */
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| 10 |
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[1765] | 11 | #include "libbb.h"
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[821] | 12 |
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[1765] | 13 | enum { RFC_868_BIAS = 2208988800UL };
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[821] | 14 |
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| 15 | static void socket_timeout(int sig)
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| 16 | {
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| 17 | bb_error_msg_and_die("timeout connecting to time server");
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| 18 | }
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| 19 |
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| 20 | static time_t askremotedate(const char *host)
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| 21 | {
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[1765] | 22 | uint32_t nett;
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[821] | 23 | int fd;
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| 24 |
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| 25 | /* Add a timeout for dead or inaccessible servers */
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| 26 | alarm(10);
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| 27 | signal(SIGALRM, socket_timeout);
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| 28 |
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[1765] | 29 | fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37));
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[821] | 30 |
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| 31 | if (safe_read(fd, (void *)&nett, 4) != 4) /* read time from server */
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| 32 | bb_error_msg_and_die("%s did not send the complete time", host);
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| 33 | close(fd);
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| 34 |
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| 35 | /* convert from network byte order to local byte order.
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| 36 | * RFC 868 time is the number of seconds
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[1765] | 37 | * since 00:00 (midnight) 1 January 1900 GMT
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| 38 | * the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT
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| 39 | * Subtract the RFC 868 time to get Linux epoch
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[821] | 40 | */
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| 41 |
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[1765] | 42 | return ntohl(nett) - RFC_868_BIAS;
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[821] | 43 | }
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| 44 |
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[1765] | 45 | int rdate_main(int argc, char **argv);
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[821] | 46 | int rdate_main(int argc, char **argv)
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| 47 | {
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| 48 | time_t remote_time;
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| 49 | unsigned long flags;
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| 50 |
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[1765] | 51 | opt_complementary = "-1";
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| 52 | flags = getopt32(argv, "sp");
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[821] | 53 |
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| 54 | remote_time = askremotedate(argv[optind]);
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| 55 |
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| 56 | if ((flags & 2) == 0) {
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| 57 | time_t current_time;
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| 58 |
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| 59 | time(¤t_time);
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| 60 | if (current_time == remote_time)
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[1765] | 61 | bb_error_msg("current time matches remote time");
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[821] | 62 | else
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| 63 | if (stime(&remote_time) < 0)
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[1765] | 64 | bb_perror_msg_and_die("cannot set time of day");
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[821] | 65 | }
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| 66 |
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| 67 | if ((flags & 1) == 0)
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| 68 | printf("%s", ctime(&remote_time));
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| 69 |
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| 70 | return EXIT_SUCCESS;
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| 71 | }
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