X-Recipient:	archive-cygwin AT delorie DOT com
DomainKey-Signature:	a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; q=dns; s=
	default; b=HetW0/wTr992ssJlXa0zp+kBS+mc06XbFxjxYhFSj0ulPrR6hugca
	ul3hoBFrIPZMIMxiB4sti1kYbDPGe6bs9fC21VdQus/gLB/eNVaABKphzWguLZEl
	PuNSUjm0xKUO0EtWeMSLivvts6t5fIrDoyM4JAhMY6NtNZME6IBXGw=
DKIM-Signature:	v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; s=default;
	bh=3Uhj7cPG3QvNppSuoRDPtD81Bq0=; b=MxvtDdp4zHlENkvqZ2+SWCEGXRWs
	OqZvcsWksgQBD0MFUB4YCGWYByexovBLwN1Gt/ZsahC6/YjBje32yo5x+BWTyFav
	Nl04ZpzhWKOCyxeZG8aS34nejyLM7LEOvBaSCqK7FbbBTkuXD800eqKGoWy77bFk
	7D6RMvpVkNGgaM8=
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
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
X-Spam-SWARE-Status:	No, score=-1.8 required=5.0 tests=AWL,BAYES_00,TO_NO_BRKTS_PCNT autolearn=ham version=3.3.1
Date:	Thu, 23 May 2013 23:14:58 +0200
From:	Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: make, PATH & "Win32 error 487"
Message-ID:	<20130523211458.GA12260@calimero.vinschen.de>
Reply-To:	cygwin AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
References:	<alpine DOT LFD DOT 2 DOT 03 DOT 1305230950500 DOT 1918 AT mcs DOT anl DOT gov> <20130523160711 DOT GB25295 AT calimero DOT vinschen DOT de>
MIME-Version:	1.0
In-Reply-To:	<20130523160711.GB25295@calimero.vinschen.de>
User-Agent:	Mutt/1.5.21 (2010-09-15)

On May 23 18:07, Corinna Vinschen wrote:
> On May 23 10:14, Satish Balay wrote:
> >   [...]
> > - It appears to be related to the huge length of one of the commands - and
> >   length of PATH
> > - I tried it on 3 different machines [with differences in default installed software]
> >   win2008/x64  - breaks when PATH is over 1.5K chars
> >   win2003/x32 - breaks when PATH is over  2K chars
> >   win7/x32    - breaks when PATH is over 20K chars.
> > 
> > Any ideas on how to debug this further to better understand the issue
> > - or workarrounds? This is with latest cygwin [and rebaseall done
> > correctly]
> 
> There's perhaps not much you can do.  First of all, the problem is known
> for a while, but even though we're trying a lot of stuff to make sure
> that fork works, the OS has some funny notions sometimes, which make it
> hard to get fork 100% reliable.
> 
> In this case, there's a subtil difference between the first shell
> started from make, and a forked subshell.  The difference is something
> to do with the size of $PATH which results in a different position of
> the main stack in the forked child process.  This breaks fork because
> fork semantics require to be able to reproduce the parent memory in the
> child process.
> 
> Thanks for the test case.  I'm just investigating what happens exactly,
> and I have a few ideas how we can workaround this problem to make fork
> a bit more reliable in this situation.  This requires some fiddling
> around, so, just stay tuned for a couple of days.

After some experimenting, it looks like I found a surprisingly simple
solution.  I checked in a patch to CVS, and I'm just generating a new
developer's snapshot.  Please try the just uploaded today's snapshot
from http://cygwin.com/snapshots/  Exchanging just the DLL should be
sufficient.  Please report back.

Btw., there's an upper bound for the size of a single environment
variable of about 32K.  Right now, if $PATH reaches this size, forking
any further process fails silently.  I don't know why yet, but as far
as I'm concerned this is no pressing issue.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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

- Raw text -