Re: [ANNOUNCE] yaird, a mkinitrd based on hotplug concepts

[Erik van Konijnenburg <ekonijn@xs4all.nl>]

On Tue, Feb 22, 2005 at 02:51:10PM +0300, Roman Kagan wrote:
> On Sat, Feb 19, 2005 at 03:00:53AM +0100, Erik van Konijnenburg wrote:
> > - the classical method: pre-compute required modules and put only
> >   those on the image,
> > - or the radical approach: put it all on the image and let hotplug
> >   sort it out at boot time.
> > 
> > - The radical approach depends on a rewrite of hotplug without shell
> > scripts (it's very difficult for mkinitrd to determine reliably which
> > executables are needed by a shell script).
> 
> But this will probably be needed in your classical approach too (I mean
> tracking of the required executables, I don't immediately see why shell
> scripts are worse in this respect).

At the moment, templating provides a limited solution.  The author of
a template can state that an action such as 'vgchange' needs
/sbin/vgchange; that's a reasonable effort when tuning a template to
a distribution, and yaird or mkinird can make it easier by handling
details such as shared libraries.

This approach breaks down when you have open-ended shell scripting,
and yaird or mkinitrd is expected to automatically find every
executable that needs to go on the image.

For example, a modprobe.conf install line that says:
	install snd-als4000 modprobe --ignore-install snd-als4000 &&
		/lib/alsa/modprobe-post-install snd-als4000

Interpreting that and determining what scripts are invoked
directly or indirectly is in general an undecidable problem.

This is one of the reasons why yaird doesn't support modprobe.conf
yet.  As an aside, it might be acceptable to simply reject install lines.
That seems to be the normal approach at the moment, and does not seem
to give rise to too many bug reports.

In the radical approach, currently you'd have to put every excutable
on the image that's used by hotplug or its agents.  That's doable,
but requires a *lot* of maintenance.  I expect this to become more
manageable one hotplug-ng is a reality.

Regards,
Erik

PS: thanks for your quick wildcard feedback; I'll dive into the patch
after going through the mail.  Notes on firmware in a next message



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