bug in vn

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2 total messages Started by roland Wed, 28 Jan 1987 03:38

#923

Author: roland
Date: Wed, 28 Jan 1987 03:38

53 lines
2282 bytes

There is a bug? in vn which will lead to a floating point exception,
divide by 0. This occurs when reading an article where headers before
the "Lines:" extend over 1 line causing artlin to be 0.
The patch below will fix vn in this case to arbitrarily display 100% 
in the reader if artlin == 0.

Roland Yap	           ACSNET,CSNET:roland@moncskermit.oz	
Dept. of Computer Science  ARPA:roland%moncskermit.oz@seismo.arpa	
Monash University          UUCP: ..!seismo!munnari!moncskermit.oz!roland	
Clayton     		  ...!{decvax,pesnta,vax135}!mulga!moncskermit.oz!roland
Australia 3168
                          moncsbruce can also be substituted for moncskermit

-----------------< cut here and submit to patch >------------------------
*** oldreader.c	Wed Jan 28 14:11:59 1987
--- reader.c	Wed Jan 28 14:09:21 1987
***************
*** 201,207
  			*/
  			if (Headflag)
  				percent = ((Rlines-2)*100)/(artlin+Hlines);
! 			else
  				percent = ((Rlines-Hlines-2)*100)/artlin;
  			sprintf (pstr,PAGE_MID,percent);
  		}

--- 201,208 -----
  			*/
  			if (Headflag)
  				percent = ((Rlines-2)*100)/(artlin+Hlines);
! 			/*	Problem here in that gethead can return artlin=0 */
! 			else if (artlin > 0.0)
  				percent = ((Rlines-Hlines-2)*100)/artlin;
  			/*	fudge with arbitrary number	*/
  			else	percent = 100;
***************
*** 203,208
  				percent = ((Rlines-2)*100)/(artlin+Hlines);
  			else
  				percent = ((Rlines-Hlines-2)*100)/artlin;
  			sprintf (pstr,PAGE_MID,percent);
  		}
  		else

--- 204,211 -----
  			/*	Problem here in that gethead can return artlin=0 */
  			else if (artlin > 0.0)
  				percent = ((Rlines-Hlines-2)*100)/artlin;
+ 			/*	fudge with arbitrary number	*/
+ 			else	percent = 100;
  			sprintf (pstr,PAGE_MID,percent);
  		}
  		else

Re: bug in vn

#929

Author: bobm
Date: Wed, 04 Feb 1987 20:01

28 lines
1700 bytes

OK, we had a discussion on this one a few weeks back.  Preventative medicine
like this is a good idea, but you should also go into the gethead() routine
in that same source and replace

	if (index(buf,':') == NULL)

with

	if (buf[0] == '\n')

To be more correct, you should incorporate a special fgets that folds the
continued header lines, such as someone posted, but given the use being
made of the header lines in this context, it probably won't matter - the
examples I've seen don't fold any relevent lines, and the Subject will
be truncated anyway.

I'm curious about something - vn has been happily running with the original
logic from the first issue of the program, and in my private copies for the
last 3 years.  Somebody has just recently started sending out the continued
lines - seemingly all articles from BITNET.  I admit that they're allowed
to do so, and that looking for the colon is a bug, but I'd still like to
know what issue of what posting software is generating the folded lines now.
Only from BITNET?  Only at 2.11 sites?  We're running 2.10.3, and I can't
say that I've ever seen such an article here.
-- 

Bob McQueer
{amdahl, sun, mtxinu, hoptoad, cpsc6a}!rtech!bobm

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