Date: Sun, 12 Jan 2003 20:14:57 -0800 (PST) From: Nate Lawson <nate@root.org> To: Sean Kelly <smkelly@zombie.org> Cc: current@freebsd.org Subject: Re: fdisk issues? Message-ID: <Pine.BSF.4.21.0301122009290.33006-100000@root.org> In-Reply-To: <20030113040247.GA816@edgemaster.zombie.org>
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On Sun, 12 Jan 2003, Sean Kelly wrote:
> edgemaster# fdisk ad1
> Floating exception (core dumped)
>
> In get_params, we have:
> ...
> 780 error = ioctl(fd, DIOCGFWSECTORS, &u);
> 781 if (error == 0)
> 782 sectors = dos_sectors = u;
> 783 error = ioctl(fd, DIOCGFWHEADS, &u);
> 784 if (error == 0)
> 785 heads = dos_heads = u;
> 786
> 787 dos_cylsecs = cylsecs = heads * sectors;
> 788 disksecs = cyls * heads * sectors;
> ...
> 794 error = ioctl(fd, DIOCGMEDIASIZE, &o);
> 795 if (error == 0) {
> 796 disksecs = o / u;
> 797 cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
> 798 }
> ...
Any disk which returns 0 for these params is broken. I put in a
workaround for the GEOM case:
sys/geom/geom_dev.c revision 1.26
date: 2002/10/15 21:28:50; author: njl; state: Exp; lines: +8 -0
Return an error if the drive reports heads/sectors that do not make sense.
This fixes a divide by zero in fdisk(8)
There should probably be an appropriate error check in fdisk to catch
problems like this instead of dumping core. The more important question
is "who in the kernel is setting these to 0?" as that part needs work too.
-Nate
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