Path: utzoo!utgpu!watserv1!watmath!att!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!uunet!viusys!alembic!csu
From: csu@alembic.acs.com (Dave Mack)
Newsgroups: comp.sources.d
Subject: Re: Obtaining time info from Naval Observatory
Message-ID: <1991Jan11.040746.7981@alembic.acs.com>
Date: 11 Jan 91 04:07:46 GMT
References: <1991Jan09.003434.5379@esleng.uucp>
Organization: Alembic Computer Services McLean VA
Lines: 154

In article <1991Jan09.003434.5379@esleng.uucp> dag@esleng.uucp (David A. Gilmour) writes:
>I have seen references to a program which can automatically obtain
>the time from the Naval Observatory and update the system clock.
>
>If anyone knows where I can get the source for this program I'd
>appreciate a note via mail.
>
>Thanks in advance.

Warren Tucker's nbstime code is pretty specific to Xenix on a PC
clone. Here's what I hacked together using that as a starting point.
I have a shar file of Warren's original if you need it. This should
run on nearly any BSD system and shouldn't be too hard to port (back)
to System V.

put this in /etc/remote (after modifying for your modem) :

# Naval Observatory Time Standard 1200 baud (202)653-0351
notime:pn=12026530351:tc=unixPEP:

then compile the following code and put the executable somewhere in
your path (I call it bsdnbs - it's a very hacked up version of
Warren Tucker's code. If there are problems, blame me, not Warren.)

Then try:

tip notime | bsdnbs

It should tell you by how many seconds your system time was changed.

Then a "~." will kill tip and hang you up.

Since it resets the system time, you have to run it as root.

bsdnbs.c:
-------------------------------- cut here --------------------------------
/*
  Warren H. Tucker, 150 West Lake Drive, Mountain Park, GA  30075
  (404)587-5766
*/
/*
 * BSD modifications, hacks to accept the Naval Obs. signal from
 * stdin, etc., due to Dave Mack, csu@alembic.acs.com.
 *
 * Compile with: cc -o bsdnbs -O bsdnbs.c
 *
 * Runs on a Sun-4, SunOS4.1
 */
#include <stdio.h>
#include <signal.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <time.h>
#include <sys/time.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>


#ifndef ushort
#define ushort	unsigned short
#endif
#ifndef uchar
#define uchar	unsigned char
#endif
#ifndef uint
#define uint	unsigned int
#endif
#ifndef ulong
#define ulong	unsigned long
#endif


#define	EPOCH		40587	/* UNIX starts JD 2440587, */
#define	leap(y, m)	((y+m-1 - 70%m) / m)	/* also known as 1/1/70 */
#define	TONE		'*'
/* #define	TIME		"\n%05ld %03d %02d%02d%02d UTC" */
#define	TIME		"%05ld %03d %02d%02d%02d UTC"

/* for better source line utilization, frequent use of 'fprintf' and 'stderr'
   warrants the following */
#define pf	printf
#define	ff	fprintf
#define se	stderr
#define so	stdout

main(argc,argv,envp)
     int		argc;
     char	**argv;
     char	**envp;
{
  char	*cptr;
  int		iargv;
  int		swchar;
  int		itmp;
  char	rd_buf[64];
  long	now;
  long	julian;
  long	time_at_connect;
  int		day_of_year;
  int		year;
  int		month;
  int		day;
  int		hour;
  int		min;
  int		sec;
  int		fdcmos;
  int		have_time = 0;
  int		max_tries;
  struct tm *lt;
  char c;
  struct timeval tp;
  struct timezone tzp;
  long oldsecs;
  for (;;) {
    /* find the designator */
    while ((c = getchar()) != '*') ;
    
    /* skip the whitespace (CRLF) */
    getchar(); getchar();
    
    /* get the time */
    cptr = rd_buf;
    while ((*cptr = getchar()) != 'C')
      cptr++;
    *(++cptr) = '\0';
    if(sscanf(rd_buf,TIME,&julian,&day_of_year,&hour,&min,&sec) != 5) {
      fprintf(stderr,"missed\n");
      continue;
    }
    else {
      have_time = 1;
      break;
    }
  }
  if(have_time) {
      now = (((julian - EPOCH) * 24 + hour) * 60 + min) * 60 + sec;
      printf("Time retrieved from standard: %s\n",ctime(&now));
      gettimeofday(&tp,&tzp);
      oldsecs = tp.tv_sec - now;
      tp.tv_sec = now;
      settimeofday(&tp,&tzp);
      printf("System time reset by %d seconds\n",oldsecs);
      exit(0);
    }
  else
    {
      printf("Did not get time ... sorry\n");
      exit(254);
    }
  
}	/* end of main */