[sane-devel] All sane frontends segfault with my HP 5200C

[Nick Lamb]

On Sun, Feb 03, 2002 at 12:52:04PM +0000, Major A wrote:
> The problem with this is that it is very platform-specific, and, even
> worse, dependent on whether you use devfs or not (in devfs, in the
> long run, major/minor numbers will be assigned dynamically).

I am finding the implicit assumption of this thread hard to believe.

Why can't you use an ioctl to distinguish SCSI devices from things which
are not SCSI devices? As far as I understood there were already
precautions in place to prevent SANE from grabbing an innocent disk and
thrashing it in the mistaken belief that it is a SCSI scanner.

e.g. On Linux, sending SCSI_IOCTL_GET_IDLUN to /dev/scanner will have
the effect of either (1) Returning some useless bus layout info which
implies that it is in fact a SCSI scanner or (2) Returning EINVALID
which means it's not a SCSI device.

I'm not picking SCSI_IOCTL_GET_IDLUN as special, I'm sure someone who
spends more time up to his/her nick in Linux sg.h will suggest a more
appropriate ioctl, however this is infinitely preferable to looking at
some static list of "special" major/minor numbers.

Nick.