Re: >256 ptys (previous subject line was garbage)
Richard Gooch (Richard.Gooch@atnf.CSIRO.AU)
Tue, 9 Jun 1998 15:57:58 +1000
david parsons writes:
> In article <linux.kernel.199806090036.KAA08187@vindaloo.atnf.csiro.au>,
> Richard Gooch <Richard.Gooch@atnf.CSIRO.AU> wrote:
> >tytso@mit.edu writes:
> >> The problem is things like /dev/modem being a symlink (or perhaps even a
> >> hard link) to /dev/ttyS0. So it would be useful to use a lockfile that
> >> includes the major and minor device number, in addition to using a
> >> lockfile that is based on the device name. The basic idea is that
> >> people want to have different device names to refer to the same device,
> >> so we need to lock based the major/minor devices.
> >
> >Well, I've seen one comment already questioning whether major/minor
> >device locks are the better way of doing it, instead of flock(2).
> >However, ignoring that, I think it would be simple enough to implement
> >a non tty-specific locking scheme in devfs. I already have the auto
> >ownership facility.
> >What does this device locking need? Just limit the number of open(2)s
> >to 1?
>
> More than that.
>
> You need a locking scheme that will support a getty listening on the
> port (one open) and will also support things that want to grab the
> port for outgoing traffic (the second open.)
What's to stop getty from receiving incoming characters which are the
result of activity by the second open?
Regards,
Richard....
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