Re: [PATCH] don't abort with error if realpath fails

[Robert Millan]

On Fri, Sep 22, 2006 at 07:42:38AM +0200, Yoshinori K. Okuji wrote:
> On Thursday 21 September 2006 19:34, Robert Millan wrote:
> > Sure.  The purpose of realpath here isn't really to verify device
> > existance; that ought to happen later if (and only if) we're actualy going
> > to use that device.
> >
> > Suppose this device.map:
> >
> > (hd0)       /dev/hda
> > (xxx)       /dev/idontexist
> >
> > Theoricaly, when grub-setup is told to act on (hd0) it shouldn't care that
> > /dev/idontexist doesn't exist (it could be listed because it was generated
> > by an older grub, because the device disappeared, etc).  However, because
> > of the realpath canonicalisation, as a collateral result we get to abort if
> > _any_ of the entries are wrong:
> 
> I understand what you mean. Thank you.
> 
> > My point is that grub should be fault tollerant and not care that
> > /dev/idontexist is broken, specialy since device.map is a file that is
> > subject for input from either user or older grub (including grub legacy),
> > and we have little control about its contents.
> 
> I describe my own opinion here. GRUB itself must be extremely fault-tolerant, 
> as the user cannot boot up a machine if GRUB fails. However, the installer of 
> GRUB must be extremely error-sensitive, as the user cannot boot up a machine 
> if the installation happens _wrongly_. If a device map contains any error, 
> it's likely that the user made some mistake or skip over erroneous 
> information. Personally I much, much prefer that GRUB is not installed in 
> this case. Failing in installing GRUB is better than making a machine 
> unbootable.

How could installation happen wrongly because of "(xxx) /dev/idontexist" ?  If
we're trying to write to (xxx), that will fail;  otherwise, it doesn't interfere
with what we're doing.

-- 
Robert Millan

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