2aeb201c97
In practice, "wget http://host.com/" always uses port 80. People explicitly set non-standard ports via options or parameters ("telnet 1.2.3.4 567" or "telnet 1.2.3.4 ftp") instead of modifying /etc/services. function old new delta telnet_main 1466 1464 -2 rdate_main 215 198 -17 fakeidentd_main 269 252 -17 parse_url 459 392 -67 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-103) Total: -103 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* The Rdate command will ask a time server for the RFC 868 time
|
|
* and optionally set the system time.
|
|
*
|
|
* by Sterling Huxley <sterling@europa.com>
|
|
*
|
|
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
|
|
*/
|
|
//config:config RDATE
|
|
//config: bool "rdate (6 kb)"
|
|
//config: default y
|
|
//config: help
|
|
//config: The rdate utility allows you to synchronize the date and time of your
|
|
//config: system clock with the date and time of a remote networked system using
|
|
//config: the RFC868 protocol, which is built into the inetd daemon on most
|
|
//config: systems.
|
|
|
|
//applet:IF_RDATE(APPLET(rdate, BB_DIR_USR_SBIN, BB_SUID_DROP))
|
|
|
|
//kbuild:lib-$(CONFIG_RDATE) += rdate.o
|
|
|
|
//usage:#define rdate_trivial_usage
|
|
//usage: "[-s/-p] HOST"
|
|
//usage:#define rdate_full_usage "\n\n"
|
|
//usage: "Set and print time from HOST using RFC 868\n"
|
|
//usage: "\n -s Only set system time"
|
|
//usage: "\n -p Only print time"
|
|
|
|
#include "libbb.h"
|
|
|
|
enum { RFC_868_BIAS = 2208988800UL };
|
|
|
|
static void socket_timeout(int sig UNUSED_PARAM)
|
|
{
|
|
bb_error_msg_and_die("timeout connecting to time server");
|
|
}
|
|
|
|
static time_t askremotedate(const char *host)
|
|
{
|
|
uint32_t nett;
|
|
int fd;
|
|
|
|
/* Timeout for dead or inaccessible servers */
|
|
alarm(10);
|
|
signal(SIGALRM, socket_timeout);
|
|
|
|
fd = create_and_connect_stream_or_die(host, bb_lookup_std_port("time", "tcp", 37));
|
|
|
|
if (safe_read(fd, &nett, 4) != 4) /* read time from server */
|
|
bb_error_msg_and_die("%s: %s", host, "short read");
|
|
if (ENABLE_FEATURE_CLEAN_UP)
|
|
close(fd);
|
|
|
|
/* Convert from network byte order to local byte order.
|
|
* RFC 868 time is seconds since 1900-01-01 00:00 GMT.
|
|
* RFC 868 time 2,208,988,800 corresponds to 1970-01-01 00:00 GMT.
|
|
* Subtract the RFC 868 time to get Linux epoch.
|
|
*/
|
|
nett = ntohl(nett) - RFC_868_BIAS;
|
|
|
|
if (sizeof(time_t) > 4) {
|
|
/* Now we have 32-bit lsb of a wider time_t
|
|
* Imagine that nett = 0x00000001,
|
|
* current time cur = 0x123ffffffff.
|
|
* Assuming our time is not some 40 years off,
|
|
* remote time must be 0x12400000001.
|
|
* Need to adjust our time by (int32_t)(nett - cur).
|
|
*/
|
|
time_t cur = time(NULL);
|
|
int32_t adjust = (int32_t)(nett - (uint32_t)cur);
|
|
return cur + adjust;
|
|
}
|
|
/* This is not going to work, but what can we do */
|
|
return (time_t)nett;
|
|
}
|
|
|
|
int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int rdate_main(int argc UNUSED_PARAM, char **argv)
|
|
{
|
|
time_t remote_time;
|
|
unsigned flags;
|
|
|
|
flags = getopt32(argv, "^" "sp" "\0" "-1");
|
|
|
|
remote_time = askremotedate(argv[optind]);
|
|
|
|
/* Manpages of various Unixes are confusing. What happens is:
|
|
* (no opts) set and print time
|
|
* -s: set time ("do not print the time")
|
|
* -p: print time ("do not set, just print the remote time")
|
|
* -sp: print time (that's what we do, not sure this is right)
|
|
*/
|
|
|
|
if (!(flags & 2)) { /* no -p (-s may be present) */
|
|
if (time(NULL) == remote_time)
|
|
bb_error_msg("current time matches remote time");
|
|
else
|
|
if (stime(&remote_time) < 0)
|
|
bb_perror_msg_and_die("can't set time of day");
|
|
}
|
|
|
|
if (flags != 1) /* not lone -s */
|
|
printf("%s", ctime(&remote_time));
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|