GNU bug report logs - #21611
probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Rainer Deyke <rainerd <at> eldwood.com>
Subject: bug#21611: closed (Re: bug#21611: probable bug in tee: tee
 overwrites argv[argc] (coreutils-8.24))
Date: Sun, 04 Oct 2015 00:07:03 +0000

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Your bug report

#21611: probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)

which was filed against the coreutils package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 21611 <at> debbugs.gnu.org.

-- 
21611: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=21611
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Rainer Deyke <rainerd <at> eldwood.com>, 21611-done <at> debbugs.gnu.org
Subject: Re: bug#21611: probable bug in tee: tee overwrites argv[argc]
 (coreutils-8.24)
Date: Sat, 3 Oct 2015 17:06:52 -0700

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Rainer Deyke wrote:
> As mentioned in a comment on line 198 of 'tee.c', 'tee' overwrites
> 'argv[argc]'.  This is very bad style at best, and probably undefined behavior
> on at least some platforms.

Thanks for the report.  It's well-defined behavior on any platform conforming to 
the C standard, so it should be quite safe.  That being said, it's a bit faster 
to subtract 1 from a pointer than to do the equivalent of a memmove of an array, 
so it sounds a bit faster to do things the way you suggest.  Cleaner, too.  I 
installed the attached patch.

[0001-tee-simplify-argv-handling.patch (text/plain, attachment)]

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From: Rainer Deyke <rainerd <at> eldwood.com>
To: bug-coreutils <at> gnu.org
Subject: probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)
Date: Sat, 3 Oct 2015 11:48:59 +0200

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As mentioned in a comment on line 198 of 'tee.c', 'tee' overwrites 
'argv[argc]'.  This is very bad style at best, and probably undefined 
behavior on at least some platforms.  The attached patch replaces the 
current hack with another hack that is still bad style, but probably 
safer than the current hack.


-- 
Rainer Deyke (rainerd <at> eldwood.com)

[patch (text/plain, attachment)]

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