Re: Move loader.c out of the kernel

[Yoshinori K. Okuji]

On Sunday 22 March 2009 23:19:09 phcoder wrote:
> Yoshinori K. Okuji wrote:
> > On Sunday 22 March 2009 22:30:24 phcoder wrote:
> >> Yoshinori K. Okuji wrote:
> >>> On Sunday 22 March 2009 22:06:36 phcoder wrote:
> >>>> Yoshinori K. Okuji wrote:
> >>>>> On Sunday 22 March 2009 21:48:21 phcoder wrote:
> >>>>>> Hello. Now when boot command isn't in kernel anymore I don't see why
> >>>>>> loader.c stays in kernel. Here is the patch to move it to boot.mod
> >>>>>
> >>>>> This is not useful in reality, because the loader interface needs to
> >>>>> be pre-loaded into core.img anyway.
> >>>>
> >>>> Why? I successfully tested core.img with just pc fat and biosdisk
> >>>> modules integrated. It loads boot.mod just fine and boots linux and
> >>>> multiboot with no problem
> >>>
> >>> Try the rescue mode with no extra module loaded. If the core.img does
> >>> not have any loader, it is useless.
> >>
> >> If it's unable to read FS then it can't boot much anyway. If it's it can
> >> load modules from its own partition. The only use I see is when grub
> >> partition is corrupted but OS one is intact and you already have FS
> >> driver for root in grub2.
> >> Alternatively commands/boot.c can be a part of minicmd
> >
> > "cannot load any more module" != "cannot read the filesystem"
> >
> > The most typical case is where the user has failed in installing GRUB
> > correctly; in this case, the user can still reset the prefix, and load
> > normal.mod manually. But, surprisingly, some users accidentally remove
> > modules. Indeed, I have heard many times this kind of "bug reports" in
> > GRUB Legacy. In this case, the only way is to boot an OS somehow and
> > re-install GRUB.
>
> Well if user damages grub2 then we can't do much. He can also accidently
>   rewrite mbr or first track (some non-booting-realted software does it
> on purpose).

I know that this is very rare by experience, in comparison with just having 
removed/broke many things from/in a filesystem.

> For failsafe solution only cd is a viable alternative 

If you have experience on maintaining remote hardware, you should know that 
this is not viable.

> grub-install already handles the correct installation of grub2.
> Additionally if user has "accidently" deleted modules chances are he
> used grub-install or some wrapper around it. But grub-install doesn't
> put any loader modules to core.img.

grub-install itself does whatever the user specifies. If your core.img does 
not include necessary modules pre-loaded, that's your mistake or your 
distributor's.

Regards,
Okuji