[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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[3232] | 4 | * and optionally set the system time.
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[821] | 5 | *
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| 6 | * by Sterling Huxley <sterling@europa.com>
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| 7 | *
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[2725] | 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 9 | */
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| 10 |
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[3232] | 11 | //usage:#define rdate_trivial_usage
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| 12 | //usage: "[-sp] HOST"
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| 13 | //usage:#define rdate_full_usage "\n\n"
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| 14 | //usage: "Get and possibly set the system date/time from a remote HOST\n"
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| 15 | //usage: "\n -s Set the system date/time (default)"
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| 16 | //usage: "\n -p Print the date/time"
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| 17 |
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[1765] | 18 | #include "libbb.h"
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[821] | 19 |
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[1765] | 20 | enum { RFC_868_BIAS = 2208988800UL };
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[821] | 21 |
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[2725] | 22 | static void socket_timeout(int sig UNUSED_PARAM)
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[821] | 23 | {
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| 24 | bb_error_msg_and_die("timeout connecting to time server");
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| 25 | }
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| 26 |
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| 27 | static time_t askremotedate(const char *host)
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| 28 | {
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[1765] | 29 | uint32_t nett;
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[821] | 30 | int fd;
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| 31 |
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| 32 | /* Add a timeout for dead or inaccessible servers */
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| 33 | alarm(10);
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| 34 | signal(SIGALRM, socket_timeout);
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| 35 |
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[1765] | 36 | fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37));
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[821] | 37 |
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[3232] | 38 | if (safe_read(fd, &nett, 4) != 4) /* read time from server */
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[821] | 39 | bb_error_msg_and_die("%s did not send the complete time", host);
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[3232] | 40 | if (ENABLE_FEATURE_CLEAN_UP)
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| 41 | close(fd);
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[821] | 42 |
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[3232] | 43 | /* Convert from network byte order to local byte order.
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[821] | 44 | * RFC 868 time is the number of seconds
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[1765] | 45 | * since 00:00 (midnight) 1 January 1900 GMT
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| 46 | * the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT
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[3232] | 47 | * Subtract the RFC 868 time to get Linux epoch.
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[821] | 48 | */
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| 49 |
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[1765] | 50 | return ntohl(nett) - RFC_868_BIAS;
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[821] | 51 | }
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| 52 |
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[2725] | 53 | int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 54 | int rdate_main(int argc UNUSED_PARAM, char **argv)
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[821] | 55 | {
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| 56 | time_t remote_time;
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[3232] | 57 | unsigned flags;
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[821] | 58 |
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[1765] | 59 | opt_complementary = "-1";
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| 60 | flags = getopt32(argv, "sp");
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[821] | 61 |
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| 62 | remote_time = askremotedate(argv[optind]);
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| 63 |
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[3232] | 64 | if (!(flags & 2)) { /* no -p (-s may be present) */
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[821] | 65 | time_t current_time;
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| 66 |
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| 67 | time(¤t_time);
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| 68 | if (current_time == remote_time)
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[1765] | 69 | bb_error_msg("current time matches remote time");
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[821] | 70 | else
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| 71 | if (stime(&remote_time) < 0)
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[2725] | 72 | bb_perror_msg_and_die("can't set time of day");
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[821] | 73 | }
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| 74 |
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[3232] | 75 | if (flags != 1) /* not lone -s */
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[821] | 76 | printf("%s", ctime(&remote_time));
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| 77 |
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| 78 | return EXIT_SUCCESS;
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| 79 | }
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