busybox/util-linux/rdate.c
Bernhard Reutner-Fischer 5c0ae06ef1 - No options should set the current system time.
Shaun Jackman writes:
A bug introduced in svn 11946 broke rdate. It no longer sets the
current system time when no options are specified. The options have
the opposite sense from what one might think, and, oddly enough, -ps
is intentionally a no-op.

Quoth rdate(8) from the BSD System Manager's Manual:

    -p      Do not set, just print the remote time
    -s      Do not print the time.
2006-06-03 10:24:20 +00:00

87 lines
1.9 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 GPL v2 or later, see file License for details.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include "busybox.h"
static const int RFC_868_BIAS = 2208988800UL;
static void socket_timeout(int sig)
{
bb_error_msg_and_die("timeout connecting to time server");
}
static time_t askremotedate(const char *host)
{
unsigned long nett;
struct sockaddr_in s_in;
int fd;
bb_lookup_host(&s_in, host);
s_in.sin_port = bb_lookup_port("time", "tcp", 37);
/* Add a timeout for dead or inaccessible servers */
alarm(10);
signal(SIGALRM, socket_timeout);
fd = xconnect(&s_in);
if (safe_read(fd, (void *)&nett, 4) != 4) /* read time from server */
bb_error_msg_and_die("%s did not send the complete time", host);
close(fd);
/* convert from network byte order to local byte order.
* RFC 868 time is the number of seconds
* since 00:00 (midnight) 1 January 1900 GMT
* the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT
* Subtract the RFC 868 time to get Linux epoch
*/
return(ntohl(nett) - RFC_868_BIAS);
}
int rdate_main(int argc, char **argv)
{
time_t remote_time;
unsigned long flags;
bb_opt_complementally = "-1";
flags = bb_getopt_ulflags(argc, argv, "sp");
remote_time = askremotedate(argv[optind]);
if ((flags & 2) == 0) {
time_t current_time;
time(&current_time);
if (current_time == remote_time)
bb_error_msg("Current time matches remote time.");
else
if (stime(&remote_time) < 0)
bb_perror_msg_and_die("Could not set time of day");
}
if ((flags & 1) == 0)
printf("%s", ctime(&remote_time));
return EXIT_SUCCESS;
}