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Message-ID: <20020803003838.87028.qmail@web21010.mail.yahoo.com>
Date: Fri, 2 Aug 2002 17:38:38 -0700 (PDT)
From: Nicholas Wourms <nwourms AT yahoo DOT com>
Subject: Re: [RFC] an alternative to rebasing
To: "Steven O'Brien" <steven DOT obrien2 AT ntlworld DOT com>, cygwin AT cygwin DOT com
In-Reply-To: <20020802151403.56afae59.steven.obrien2@ntlworld.com>
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--- Steven O'Brien <steven DOT obrien2 AT ntlworld DOT com> wrote:
> I may have found a way of getting cygwin fork() to load dlls
> reliably
> without the need for rebasing dlls.
> 
> I described my understanding of the problem in a previous post
> (http://www.cygwin.com/ml/cygwin/2002-07/msg01260), but basically
> it
> boils down to the fact that during fork() the child process does
> not
> load dlls in the same order as the parent, and consequently cannot
> always get them to the same address. I would be difficult to record
> and
> reproduce the full sequence of LoadLibrary/FreeLibrary calls, but
> after
> some experimentation I believe that there is an alternative. If the
> child loads dlls in the order that they are in memory in the
> parent,
> then it appears to get the correct addresses. To test this I
> patched
> cygwin1.dll so that a list of loaded dlls, in address order, is
> maintained, and the child walks this list instead of the existing
> list
> of all dlls.
> 
> I have done some simple tests that fail with cygwin1.dll-1.3.12-2,
> but
> succeed with my patched dll. I am also running the gnome desktop
> and
> core apps which depend on run-time loaded dlls to function and that
> is
> OK. I would like package maintainers who would otherwise need
> rebasing 
> (Jason?) to try my patch and report results here if they can find
> time.
> 
> If this approach proves successful, then rebasing would still
> improve
> load time for dlls, but apps using run-time loading of dlls would
> no
> longer depend on rebase to function. 
> 
> Attached is the patch and a Changelog entry

Steve,

If this works, I can't thank you enough.  I'll report back on how it
does with our problem child - Apache...

Cheers,
Nicholas

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