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/* 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>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <getopt.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include "busybox.h"
static const int RFC_868_BIAS = 2208988800UL;
static time_t askremotedate(const char *host)
{
struct hostent *h;
struct sockaddr_in sin;
struct servent *tserv;
unsigned long int nett, localt;
int fd;
if (!(h = gethostbyname(host))) /* get the IP addr */
perror_msg_and_die("%s", host);
if ((tserv = getservbyname("time", "tcp")) == NULL) /* find port # */
perror_msg_and_die("%s", "time");
if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) /* get net connection */
perror_msg_and_die("%s", "socket");
memcpy(&sin.sin_addr, h->h_addr, sizeof(sin.sin_addr));
sin.sin_port= tserv->s_port;
sin.sin_family = AF_INET;
if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) /* connect to time server */
perror_msg_and_die("%s", host);
if (read(fd, (void *)&nett, 4) != 4) /* read time from server */
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
*/
localt= ntohl(nett) - RFC_868_BIAS;
return(localt);
}
int rdate_main(int argc, char **argv)
{
time_t time;
int opt;
int setdate = 0;
int printdate= 0;
/* Interpret command line args */
/* do special-case option parsing */
if (argv[1] && (strcmp(argv[1], "--help") == 0))
show_usage();
/* do normal option parsing */
while ((opt = getopt(argc, argv, "Hsp")) > 0) {
switch (opt) {
default:
case 'H':
show_usage();
break;
case 's':
setdate++;
break;
case 'p':
printdate++;
break;
}
}
/* the default action is to set the date */
if (printdate==0 && setdate==0) setdate++;
if (optind == argc)
show_usage();
time = askremotedate(argv[optind]);
if (setdate) {
if (stime(&time) < 0)
perror_msg_and_die("Could not set time of day");
}
if (printdate)
printf("%s", ctime(&time));
return EXIT_SUCCESS;
}
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