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To: Jeff Dike <jdike@addtoit.com>
Cc: Joshua Hudson <joshudson@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [OT] 'volatile' in userspace
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From: Philippe Troin <phil@fifi.org>
Date: 10 Jul 2006 13:09:47 -0700
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Jeff Dike <jdike@addtoit.com> writes:

> On Mon, Jul 10, 2006 at 10:00:37AM -0700, Joshua Hudson wrote:
> > Yes, I use vfork. So far, the only way I have found for the parent to
> > know whether or not the child's exec() failed is this way:
> 
> What I do in UML is make a pipe between the parent and child, set it
> CLOEXEC, and write a byte down it if the exec fails.
> 
> The parent reads it - if it gets no bytes, the exec succeeded, if it
> gets one byte, it failed.

I usually do the same, except that I write the errno in case of
failure.  This way the parent knows *why* exec failed ;-)

Phil.