Date: Mon, 25 Oct 2004 11:29:17 -0400
From: Mike Waychison <Michael.Waychison@Sun.COM>
Subject: Re: [PATCH 20/28] HOTPLUG: call_usermodehelper callback support
In-reply-to: <20041025151842.GA1858@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
       raven@themaw.net
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 <20041025151842.GA1858@infradead.org>
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Christoph Hellwig wrote:
> On Mon, Oct 25, 2004 at 10:48:40AM -0400, Mike Waychison wrote:
> 
>>This patch extends the call_usermodehelper api by adding a callback variant.
>>The callback is made right when the system is about to call execve into the
>>new process.  This allows for the caller to provide changes to the default
>>environment right before the exec takes place.  Note: the context of the
>>callback will be _from within another process_.
> 
> 
> I don't like this at all.  First it's the usual fork() + exec() vs spawn() with
> gazillions of arguments debatte, second this sounds far too complex to do it in
> kernelspace to me.  Why can't you do the enviroment changes from the program
> beeing executed?
> 

I want to be able to do two things:

- - To 'call_usermodehelper' a program, but in current's namespace.
Namespaces can't be passed around in userspace.

- - To give the execed program an open file.  The current interface
doesn't allow me to do that.

I figured the _cb way of doing it remove any need for adding ad-hoc api
anytime somebody wants to tweak a task before calling execve.

Does this clarify why I added this?

- --
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice

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