Re: [PATCH] Fix when installing on pationless but partionable medium

[Robert Millan <rmh@aybabtu.com>]

On Fri, Jul 17, 2009 at 06:41:59PM +0200, Vladimir 'phcoder' Serbinenko wrote:
> Sometimes a media that can be partioned isn't really partioned. E.g.
> usb sticks. This is a patch to handle this situation.

But we had a check for this already, is it not working?

  if (! dest_dev->disk->has_partitions)
    { 
      grub_util_warn ("Attempting to install GRUB to a partitionless disk.  This is a BAD idea.");
      goto unable_to_embed;
    }

> Unfortunately
> such medium is often formated with a flavour of FAT which shares its
> signature with MBR so it may be easily misidentified as
> pc_partition_table. Furthermore the same signature is shared with
> bootsectors including grub. One possibility is to try interpret disk
> as known filesystems and see if we succeed. But the problem is that
> the check for FAT are light and may result in false positives too. The
> only more or less advanced check there is a check for FATXX string.
> But I was about to propose to eliminate this check since I encountered
> a FAT filesystem without this string on friend's SD card formatted
> with symbian which he wanted to use as liveusb. Does anyone has a
> better idea?

I'm not sure there's much we can do about this.  Using heuristics sounds like
it will make the solution worse than the problem.  I don't care much about
Microsoft filesystems, but I'd hate to see GRUB fail on a completely sane
ext3 inside msdos label because it happened to look like FAT in raw disk at
the same time.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."