source: branches/3.2/mindi-busybox/util-linux/rdate.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 2.0 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * The Rdate command will ask a time server for the RFC 868 time
4 * and optionally set the system time.
5 *
6 * by Sterling Huxley <sterling@europa.com>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9*/
10
11//usage:#define rdate_trivial_usage
12//usage:       "[-sp] HOST"
13//usage:#define rdate_full_usage "\n\n"
14//usage:       "Get and possibly set the system date/time from a remote HOST\n"
15//usage:     "\n    -s  Set the system date/time (default)"
16//usage:     "\n    -p  Print the date/time"
17
18#include "libbb.h"
19
20enum { RFC_868_BIAS = 2208988800UL };
21
22static void socket_timeout(int sig UNUSED_PARAM)
23{
24    bb_error_msg_and_die("timeout connecting to time server");
25}
26
27static time_t askremotedate(const char *host)
28{
29    uint32_t nett;
30    int fd;
31
32    /* Add a timeout for dead or inaccessible servers */
33    alarm(10);
34    signal(SIGALRM, socket_timeout);
35
36    fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37));
37
38    if (safe_read(fd, &nett, 4) != 4)    /* read time from server */
39        bb_error_msg_and_die("%s did not send the complete time", host);
40    if (ENABLE_FEATURE_CLEAN_UP)
41        close(fd);
42
43    /* Convert from network byte order to local byte order.
44     * RFC 868 time is the number of seconds
45     * since 00:00 (midnight) 1 January 1900 GMT
46     * the RFC 868 time 2,208,988,800 corresponds to 00:00  1 Jan 1970 GMT
47     * Subtract the RFC 868 time to get Linux epoch.
48     */
49
50    return ntohl(nett) - RFC_868_BIAS;
51}
52
53int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
54int rdate_main(int argc UNUSED_PARAM, char **argv)
55{
56    time_t remote_time;
57    unsigned flags;
58
59    opt_complementary = "-1";
60    flags = getopt32(argv, "sp");
61
62    remote_time = askremotedate(argv[optind]);
63
64    if (!(flags & 2)) { /* no -p (-s may be present) */
65        time_t current_time;
66
67        time(&current_time);
68        if (current_time == remote_time)
69            bb_error_msg("current time matches remote time");
70        else
71            if (stime(&remote_time) < 0)
72                bb_perror_msg_and_die("can't set time of day");
73    }
74
75    if (flags != 1) /* not lone -s */
76        printf("%s", ctime(&remote_time));
77
78    return EXIT_SUCCESS;
79}
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