getdate && Y2K

[Andreas Jaeger <aj@arthur.rhein-neckar.de>]

Hi,

I've downloaded some Y2K test programs from:
ftp://ftp.rdg.opengroup.org/pub/unsupported/stdtools/y2k/

and got a segmentation fault using the getdate.c program :-(.

Could somebody check if either the testprogram (appended below) or the
getdate implementation in glibc2.1 is broken and fix it?

Thanks,
Andreas

/* 

 * getdate() %y checker

 * 

 * Note that UNIX systems are required only to be able to

 * represent dates up until between Jan 1 1970 and Jan 1 2038,

 * some systems may be able to handle a wider range but its

 * not required. 

 *

 * Symptons of the non handling of the range is a core dump,

 * if this occurs see below -re TOG_END

 * 

 * This test requires a file called datemsk to be in the current

 * directory with the contents "%d/%m/%y"

 *

 * Author: Andrew Josey, (ajosey@xopen.org)

 * Based on the idea seen for a  test for strptime on comp.unix.aix

 * reworked to allow for the Jan 1 1970 - Jan 1 2038 limits on 

 * some systems.

 */



#ifndef lint

static char *_version = "@(#)getdate_win.c 1.1 - 98/06/08";

#endif

/*

 * Determine window for the getdate() function.

 */

#include <stdio.h>

#include <time.h>

#include <stdlib.h>

#ifdef sun

#include <tzfile.h>

#else

#define TM_YEAR_BASE 1900

#endif



main()

{

 int i;

 struct tm tm_struct, *tm_ptr;

 char buf[9];

 int years[100];

 char s[20];



 tm_ptr = &tm_struct;



 sprintf (s, "DATEMSK=./datemsk");

 putenv(s);



/* some systems may handle 0 to 100, if so change the 38

 * to 100 and the next code block will disappear 

 */



#define TOG_START 0   

#define TOG_END 100  

/*#define TOG_END 38  */  /* comment in if core dumps occur */



 for (i = TOG_START ; i < TOG_END; i++) {

  sprintf(buf, "01/01/%02d", i);

/*  printf("i=%d,template=%s\n",i, buf);*/

  tm_ptr = getdate (buf);

  years[i] = tm_ptr->tm_year + TM_YEAR_BASE;

/*  printf("YEAR=%d\n", years[i]);*/

 }



#if (TOG_END - 38 == 0)

 for (i = 69; i < 100; i++) {

  sprintf(buf, "01/01/%02d", i);

/*  printf("i=%d,template=%s\n",i, buf);*/

  tm_ptr = getdate (buf);

  years[i] = tm_ptr->tm_year + TM_YEAR_BASE;

/*  printf("YEAR=%d\n", years[i]);*/

 }

#endif



 printf("getdate(3C) window: %04d-", years[0]);

 for (i = 1; i <  TOG_END; i++) {

  if (years[i-1] / 100 != years[i] / 100)

   printf("%04d %04d-", years[i-1], years[i]);

 }

 printf("%04d ", years[TOG_END-1]);



#if (TOG_END - 38 == 0)



 printf("%04d-", years[69]);

 for (i = 70; i <  100; i++) {

  if (years[i-1] / 100 != years[i] / 100)

   printf("%04d %04d-", years[i-1], years[i]);

 }

 printf("%04d\n", years[99]);

#endif



 exit(0);

 return (0);  /* quiet lint gripes */

}




%m/%d/%y

Programs to interrogate the systems handling of two digit dates
---------------------------------------------------------------

Module: getdate.c

Description:

struct tm *getdate(const char *string);

The X/Open CAE Specification, System Interfaces and Headers Issue 4,
Version 2 (September 1994), in the entry for getdate() on page 231,
states the following with respect to the format code %y:

        "%y     year within century (00-99)"

Suppose there is a line of the form "%m/%d/%y" in the template file,
and a call is made:

    struct tm * p_tm;
    p_tm = getdate( "11/22/02" ); 

It is not specified what would be represented in the struct tm for the
century. This could be interpreted as either 11/22/1902 or 11/22/2002
since the implementation does not know which "century" this is to refer
to.

This test module has a DATEMSK of "%d/%m/%y" and will call
getdate() with a date of "01/01/%2d" where %2d will increment from
00 to 99. The test module will then print out the windows that the
getdate() function handles, for example

	getdate(3C) window: 2000-2068 1969-1999

Note that the Single UNIX Specification only requires that systems
be able to represent the time between Jan 1 1970 and Jan 1 2038,
thus some systems will have a window of 2000-2038 rather than 2000-2068.

To enable the test to work on those systems edit the TOG_END
value from 99 to 38.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Module: strptime.c

Description:


char *strptime(const char *buf, const char *format, struct tm *tm);

The X/Open CAE Specification, System Interfaces and Headers Issue 4,
Version 2 (September 1994), in the entry for strptime() on page 615,
states the following with respect to the format code %y:

        "%y     is the year within century [00,99]; leading zeros are
                permitted but not required"

Suppose that the following call is made: 


    struct tm thetime;
    strptime( "11/22/02", "%m/%d/%y", &thetime );

It is not specified what would be represented in the struct tm for the
century. This could be interpreted as either 11/22/1902 or 11/22/2002
since the implementation does not know which "century" this is to refer
to.

The test module takes a similar strategy to  getdate.c.
Typical outlook looks like:

	strptime(3C) window: 2000-2068 1969-1999
or
	strptime(3C) window: 2000-2038 1969-1999


-- 
 Andreas Jaeger   aj@arthur.rhein-neckar.de    jaeger@informatik.uni-kl.de
  for pgp-key finger ajaeger@aixd1.rhrk.uni-kl.de