linux-kernel - Re: Feature request: exec self for NOMMU.

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Message-Id: <200612270524.36157.vda.linux@googlemail.com>
Date:	Wed, 27 Dec 2006 05:24:36 +0100
From:	Denis Vlasenko <vda.linux@...glemail.com>
To:	David Lang <david.lang@...italinsight.com>
Cc:	Rob Landley <rob@...dley.net>, linux-kernel@...r.kernel.org,
	David McCullough <david_mccullough@...securecomputing.com>
Subject: Re: Feature request: exec self for NOMMU.

On Wednesday 27 December 2006 00:55, David Lang wrote:
> On Tue, 26 Dec 2006, Rob Landley wrote:
> 
> > I'm trying to make some nommu-friendly busybox-like tools, which means using
> > vfork() instead of fork().  This means that after I fork I have to exec in
> > the child to unblock the parent, and if I want to exec my current executable
> > I have to find out where it lives so I can feed the path to exec().  This is
> > nontrivial.
> >
> > Worse, it's not always possible.  If chroot() has happened since the program
> > started, there may not _be_ a path to my current executable available from
> > this process's current or root directories.
> 
> does this even make sense (as a general purpose function)? if the executable 
> isn't available in your path it's likly that any config files it needs are not 
> available either.

busybox needs it in order to spawn, for example, gzip/bzip2 helper
for tar. We know that our own executable has this function.
How to execute _our own executable_? exec("/proc/self/exe")
works only if /proc is mounted. I can imagine that some embedded
people want to be able to not rely on that.
--
vda
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