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Date: Sun, 15 Sep 2002 22:06:51 +0200
From: Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>
To: Pozsar Balazs <pozsy@uhulinux.hu>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG?] binfmt_script: interpreted interpreter doesn't work
Message-ID: <20020915220651.C642@nightmaster.csn.tu-chemnitz.de>
Reply-To: Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>
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In-Reply-To: <Pine.GSO.4.30.0209151910220.22107-100000@balu>; from pozsy@uhulinux.hu on Sun, Sep 15, 2002 at 07:15:38PM +0200
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Hi Pozsar,

On Sun, Sep 15, 2002 at 07:15:38PM +0200, Pozsar Balazs wrote:
> This may well not be bug, rather an intended feature, but please enlighten
> me why the following doesn't work:
> 
> I have two scripts:
> /home/pozsy/a:
> #!/bin/sh
> echo "Hello from a!"
> 
> /home/pozsy/b:
> #!/home/pozsy/a
> echo "hello from b!"
> 
> Both of them has +x permissions.
> But I cannot execute the /home/pozsy/b script:
> 
> Isn't this "indirection" allowed?

Right, this isn't allowed to avoid eating kernel resources
without getting anything done.

Solution is to always compile an interpreter or to write 
a wrapper in C, which is compiled and calls the perl interpreter
with your perl script. This wrapper would be ANSI-C with really
basic POSIX extensions and should thus be as portable as perl ;-)

So you hide the indirection from the kernel this way.

Of course you now define the wrapper as the interpreter for your
perl scripts.

Hope that helps.

Regards

Ingo Oeser
-- 
Science is what we can tell a computer. Art is everything else. --- D.E.Knuth
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