source: branches/2.2.9/mindi-busybox/util-linux/rdate.c @ 2725

Last change on this file since 2725 was 2725, checked in by Bruno Cornec, 9 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
File size: 1.7 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#include "libbb.h"
12
13enum { RFC_868_BIAS = 2208988800UL };
14
15static void socket_timeout(int sig UNUSED_PARAM)
16{
17    bb_error_msg_and_die("timeout connecting to time server");
18}
19
20static time_t askremotedate(const char *host)
21{
22    uint32_t nett;
23    int fd;
24
25    /* Add a timeout for dead or inaccessible servers */
26    alarm(10);
27    signal(SIGALRM, socket_timeout);
28
29    fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37));
30
31    if (safe_read(fd, (void *)&nett, 4) != 4)    /* read time from server */
32        bb_error_msg_and_die("%s did not send the complete time", host);
33    close(fd);
34
35    /* convert from network byte order to local byte order.
36     * RFC 868 time is the number of seconds
37     * since 00:00 (midnight) 1 January 1900 GMT
38     * the RFC 868 time 2,208,988,800 corresponds to 00:00  1 Jan 1970 GMT
39     * Subtract the RFC 868 time to get Linux epoch
40     */
41
42    return ntohl(nett) - RFC_868_BIAS;
43}
44
45int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
46int rdate_main(int argc UNUSED_PARAM, char **argv)
47{
48    time_t remote_time;
49    unsigned long flags;
50
51    opt_complementary = "-1";
52    flags = getopt32(argv, "sp");
53
54    remote_time = askremotedate(argv[optind]);
55
56    if ((flags & 2) == 0) {
57        time_t current_time;
58
59        time(&current_time);
60        if (current_time == remote_time)
61            bb_error_msg("current time matches remote time");
62        else
63            if (stime(&remote_time) < 0)
64                bb_perror_msg_and_die("can't set time of day");
65    }
66
67    if ((flags & 1) == 0)
68        printf("%s", ctime(&remote_time));
69
70    return EXIT_SUCCESS;
71}
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