Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com
Date:	Fri, 16 Sep 2005 12:48:05 -0400
From:	Christopher Faylor <cgf-no-personal-reply-please AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: Bash login breaks if too many environment variables are set
Message-ID:	<20050916164805.GA30657@trixie.casa.cgf.cx>
Reply-To:	cygwin AT cygwin DOT com
References:	<091620051636 DOT 3255 DOT 432AF47000065F0D00000CB722007456720A050E040D0C079D0A AT comcast DOT net>
Mime-Version:	1.0
In-Reply-To:	<091620051636.3255.432AF47000065F0D00000CB722007456720A050E040D0C079D0A@comcast.net>
User-Agent:	Mutt/1.5.8i

On Fri, Sep 16, 2005 at 04:36:00PM +0000, Eric Blake wrote:
>>>It looks to me as if a buffer or stack is reused if some maximum is
>>>exceeded with effect that the system sometimes works.
>>
>>From your strace output, it looks to me like windows itself is
>>returning garbage when we ask it for the list of environment variables.
>
>I don't think all places in Windows have the limitation.

Look at the code.  We're inspecting a buffer returned from
GetEnvironmentStrings.  That is a windows function.  The very first
things returned from this are garbage.

>Corinna reported (and I have reproduced on Win2k, CYGWIN-NT-5.0) that
>it is quite easy to create an environment larger than 32k and see it in
>a child process:
>
>$ foo=`perl -e 'print "a"x31000'`
>$ export foo $ /bin/env | wc -c 34664
>$ /bin/env | wc -c
>34664

You're not testing the same thing.  Cygwin deals with environment
variables on its own once you've started a cygwin process.  It only
relies on windows environment-passing mechanisms to pass environment
variables to non-cygwin applications.

I have a new version of a cygwin snapshot which has more debugging
output and which should (temporarily?) fail with an error if environment
processing fails.

cgf

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

- Raw text -