On Wed, Jun 04, 2008 at 09:47:17PM -0400, Pavel Roskin wrote: > On Thu, 2008-06-05 at 01:35 +0200, Robert Millan wrote: > > It seems that open_device() in biosdisk is messing up offsets when > > accessing partitions. For example if you try: > > > > grub> hexdump (hd0,1) > > > > in grub-emu, you'll get a message saying lseek failed. The problem is that > > it substracts to the sector offset, so all accesses get to wrong data and > > accessing sector 0 results in underflow. > > > > I would think those lines (see patch) are plainly wrong, but they appear to > > be very old, and it is strange that this wasn't noticed earlier. Maybe we > > have changed behaviour around partition/disk offsets, causing this breakage > > without noticing? > > The question whether sector is relative to the partition or to the whole > disk. From what I see in disk/memdisk.c or it disk/i386/pc/biosdisk.c, > the sector is relative to the whole disk. There is no compensation for > partition offsets. That's low-level code that doesn't know about > partitions, and util/biosdisk.c correctly tries to emulate that. > > I guess grub-emu gets it wrong somewhere.
grub-emu itself does nothing about this AFAIK, it just relies on util/biosdisk.c to do the right thing. -- Robert Millan <GPLv2> I know my rights; I want my phone call! <DRM> What good is a phone call… if you are unable to speak? (as seen on /.) _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
