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Date: Mon, 29 Jan 2024 12:16:40 +0100
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin-patches@cygwin.com
Subject: Re: [PATCH 1/5] Cygwin: Make 'ulimit -c' control writing a coredump
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On Jan 27 15:12, Jon Turney wrote:
> On 26/01/2024 11:52, Corinna Vinschen wrote:
> > > - Create a named mutex with a reproducible name (no need to use
> > >    the name as parameter) and immediately grab it.
> > > - Call CreateProcess to start the debugger with CREATE_SUSPENDED
> > >    flag.
> > > - Create a HANDLE array with the mutex and the process HANDLE.
> > 
> >      On second thought, it might be a good idea to make this
> >      interruptible as well, but given this is called from the
> >      exception handler this may have weird results...
> > > - Call ResumeThread on the primary debugger thread.
> > > - Call WFMO with timeout.
> > > 
> > > Later on, the debugger either fails and exits or it calls
> > > ReleaseMutex after having attached to the process.
> > > 
> > > - WFMO returns
> > > - If the mutex has triggered, we're being debugged (but check
> > >    IsDebuggerPresent() just to be sure)
> > > - If the process has triggered, the debugger exited
> > > - If the timeout triggers... oh well.
> 
> This seems like quite a lot of work, for very marginal benefit.
> 
> And doing lots of complex work inside the process when we're in the middle
> of handling a SEGV seems like asking for trouble.
> 
> I think I'll leave this alone for the moment, and we can see what (if any)
> problems surface.

Ok, no worries.


Corinna