Re: GRUB patch for 'lilo -R' functionality

[Keir Fraser]

> > I only changed the behaviour of savedefault when executed within the
> > GRUB-util shell (ie. not GRUB menu mode). I can't think of a scenario
> > where the '--once' semantics would be useful to access from the GRUB
> > menu, so I'm reluctant to 'fix' this behaviour.
> 
> I think there's a missunderstanding here. savedefault itself is only
> meaningful in the context of the menu. The problem I noticed is that while
> "savedefault --default=X" affects the GRUB menu, the "--once" argument has
> no effect. I.e: once you run savedefault it won't be restored to 0 after the
> next GRUB run.

Yes, clearly there is a misunderstanding!

Without my patch it is indeed the case that savedefault has no meaning
outside the GRUB menu script. It's only use in that context is to
cause GRUB to default to "what you last picked".

My patch makes savedefault useful in the context of the GRUB
shell. Specifying --once to savedefault in the GRUB shell will cause
teh following behavior:
 1. The specified default will be used on next boot.
 2. Any specified timeout will be ignored on next boot (i.e. the menu
    won't even be displayed).
 3. After next boot, the above behaviour will be disabled until next
    use of savedefault --once from GRUB shell.

The above semantics isn't even useful from the GRUB menu script -- it
would simply cause GRUB to continually boot straight into the same
'default' again and again; and never again display the menu (think
about it).

Maybe I should have created a new command name instead of confusingly
overloading savedefault in this way. :-(  In fact, I think adding a
new command, useable only from GRUB shell, would be quite easy.

 -- Keir