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From: Michael Enright <mike AT kmcardiff DOT com>
Date: Thu, 12 Jan 2017 16:54:04 -0800
Message-ID: <CAOC2fq9Q24wyBqCqx15oejCiOK88P41vgbZ5Rm0ZUZcxNzwVsg@mail.gmail.com>
Subject: Re: Hangs on connect to UNIX socket being listened on in the same process (was: Cygwin hanging in pselect)
To: cygwin AT cygwin DOT com
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On Thu, Jan 12, 2017 at 2:13 PM, Corinna Vinschen
<corinna-cygwin AT cygwin DOT com> wrote:
> Step 3:
>
>   If we did it really intelligent, maybe we finally also have a method
>   to implement descriptor passing.  Finally.  After all these years.
>
> And maybe, we should not actually use the socket itself to exchange
> the information but rather create some kind of side-channle for that.
>
> Especially in terms of step 3, I'm mulling over this for years now
> and always something else got in the way and had to be done first.
>
>

I made a program that needed to pass windows HANDLEs between processes
and so that receiving process could access the shared memory
represented by the HANDLEs. I was emulating facilities many programs
implement using send_msg, but I was using Windows (named?) pipes. It
felt a lot like what you need for send_msg, and it required newer
Windows APIs. So by doing the crazy thing of completely rewriting your
AF_UNIX sockets you could "easily" add descriptor passing.

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