[PATCH 4/5] pxe_utils: Support a backup for localboot

[Simon Glass]

Hi Tom,

On Fri, 20 Dec 2024 at 07:56, Tom Rini <trini at konsulko.com> wrote:
>
> On Thu, Dec 19, 2024 at 09:01:19PM -0700, Simon Glass wrote:
>
> > The current localboot implementation assumes that a 'localcmd'
> > environment variable is provided, with the instructions to follow. This
> > may not be included, so provide a fallback in that case.
> >
> > Add a test image and test as well.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
>
> This is a pretty niche feature, I had to dig around a bit to see how
> it's specified elsewhere (not really) and how it's used. And I think
> that based on how it's used, making up a bootcmd when localcmd is
> undefined is the wrong approach. It's the hook for "run what I defined
> in the environment", so if not set erroring back out seems appropriate.

Yes, but unfortunately it seems to be used and we should support it.
The problem with scripts is that we don't know the boot device, etc,
so it needs to be integrated into PXE. I did consider putting
something in bootstd, but we only find out that it is requesting a
localboot when actually running the extlinux bootmeth, so this is what
I came up with.

It will be interesting to see if any other cases come up.

Regards,
Simon