Re: Reproducible grub-install

From: Daniel Kiper <dkiper@net-space.pl>
To: Miguel Arruga Vivas <rosen644835@gmail.com>
Cc: guix-devel@gnu.org, grub-devel@gnu.org
Subject: Re: Reproducible grub-install
Date: Wed, 23 Oct 2019 11:09:07 +0200	[thread overview]
Message-ID: <20191023090907.6sfuq6ne5mipdc5r@tomti.i.net-space.pl> (raw)
In-Reply-To: <20191021163021.1a3ca543@gmail.com>

On Mon, Oct 21, 2019 at 04:30:21PM +0200, Miguel Arruga Vivas wrote:
> Hi, everybody!
>
> After taking a deeper look into our (guix's) grub installation
> procedure, I have the thought that it could be a neat idea to make the
> boot directory an actual derivation instead something of the global
> status.

I do not understand what you mean by "make the boot directory an actual
derivation instead something of the global status". Could you elaborate
more about that?

> From what I currently understand:
>
>   - boot.img/core.img and load.cfg: The written images must be replaced
>     on each installation.  This is one task performed by grub-install.

Yep.

>   - /boot/grub/*: The contents of these folders should be reproducible,
>     such as the modules or the localization binaries, as currently
>     grub.cfg is.  This is the other task performed by grub-install.

I am not sure why grub.cfg have to be reproducible. OK, to some extent
it has but...

>
>   - /boot/grub/grubenv: IIUC, this file must be writable by grub.  This
>     should not be on the store, and not sharing the path may be the
>     main problem right now to implement this.

I do not understand this.

> AFAIK, the grubenv problem requires a modification of the grub code if
> we try to use a different path for this kind-of-modifiable file, so this
> would require modify grub to being able to lookup for that file
> somewhere else.  This way the global state can be made explicit.

What do you mean by "This way the global state can be made explicit."?

> The image installation into the device is a separate issue from the
> binaries installation, that could be separated into two separate
> binaries, or two steps/flags for grub-install, one for binaries
> installation into ${boot-directory}/grub and the other one for load.cfg
> generation and core/boot.img installation.

Why do you need to separate this thing into two steps?

> To everyone: Are you aware of any other way to achieve this?  What do
> you think?
>
> To grub-devel: I'd be able to send patches for the latter if you think

Patches are always welcome...

> it is a good idea without help, but I guess that the first kind of
> modification would need some and deeper study of grub code.
>

Yep...

Daniel