blob: 51d5eb6ae2d342d7bd96e54ac89a336f20f4b0f9
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 | //config:config RDATE |
11 | //config: bool "rdate" |
12 | //config: default y |
13 | //config: help |
14 | //config: The rdate utility allows you to synchronize the date and time of your |
15 | //config: system clock with the date and time of a remote networked system using |
16 | //config: the RFC868 protocol, which is built into the inetd daemon on most |
17 | //config: systems. |
18 | |
19 | //applet:IF_RDATE(APPLET(rdate, BB_DIR_USR_SBIN, BB_SUID_DROP)) |
20 | |
21 | //kbuild:lib-$(CONFIG_RDATE) += rdate.o |
22 | |
23 | //usage:#define rdate_trivial_usage |
24 | //usage: "[-sp] HOST" |
25 | //usage:#define rdate_full_usage "\n\n" |
26 | //usage: "Get and possibly set system time from a remote HOST\n" |
27 | //usage: "\n -s Set system time (default)" |
28 | //usage: "\n -p Print time" |
29 | |
30 | #include "libbb.h" |
31 | #include <android.h> |
32 | |
33 | |
34 | enum { RFC_868_BIAS = 2208988800UL }; |
35 | |
36 | static void socket_timeout(int sig UNUSED_PARAM) |
37 | { |
38 | bb_error_msg_and_die("timeout connecting to time server"); |
39 | } |
40 | |
41 | static time_t askremotedate(const char *host) |
42 | { |
43 | uint32_t nett; |
44 | int fd; |
45 | |
46 | /* Add a timeout for dead or inaccessible servers */ |
47 | alarm(10); |
48 | signal(SIGALRM, socket_timeout); |
49 | |
50 | fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37)); |
51 | |
52 | if (safe_read(fd, &nett, 4) != 4) /* read time from server */ |
53 | bb_error_msg_and_die("%s: %s", host, "short read"); |
54 | if (ENABLE_FEATURE_CLEAN_UP) |
55 | close(fd); |
56 | |
57 | /* Convert from network byte order to local byte order. |
58 | * RFC 868 time is the number of seconds |
59 | * since 00:00 (midnight) 1 January 1900 GMT |
60 | * the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT |
61 | * Subtract the RFC 868 time to get Linux epoch. |
62 | */ |
63 | |
64 | return ntohl(nett) - RFC_868_BIAS; |
65 | } |
66 | |
67 | int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
68 | int rdate_main(int argc UNUSED_PARAM, char **argv) |
69 | { |
70 | time_t remote_time; |
71 | unsigned flags; |
72 | |
73 | opt_complementary = "-1"; |
74 | flags = getopt32(argv, "sp"); |
75 | |
76 | remote_time = askremotedate(argv[optind]); |
77 | |
78 | if (!(flags & 2)) { /* no -p (-s may be present) */ |
79 | time_t current_time; |
80 | |
81 | time(¤t_time); |
82 | if (current_time == remote_time) |
83 | bb_error_msg("current time matches remote time"); |
84 | else |
85 | if (stime(&remote_time) < 0) |
86 | bb_perror_msg_and_die("can't set time of day"); |
87 | } |
88 | |
89 | if (flags != 1) /* not lone -s */ |
90 | printf("%s", ctime(&remote_time)); |
91 | |
92 | return EXIT_SUCCESS; |
93 | } |
94 |