Re: >256 ptys (previous subject line was garbage)
Richard Gooch (Richard.Gooch@atnf.CSIRO.AU)
Wed, 10 Jun 1998 10:32:56 +1000
tytso@mit.edu writes:
> Date: Tue, 9 Jun 1998 10:36:38 +1000
> From: Richard Gooch <Richard.Gooch@atnf.CSIRO.AU>
>
> Well, I've seen one comment already questioning whether major/minor
> device locks are the better way of doing it, instead of flock(2).
>
> flock(2) simply doesn't work because you may need to keep a tty locked
> beyond the lifetime of the process which originally locked the tty.
>
> 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?
>
> tty locking really doesn't belong in the kernel. It's a lot more
> complex than limiting the number of open's to 1. You need to worry
> about people who have a blocking open waiting for carrier detect going
> high; you need to worry with multiple processes opening /dev/tty when
> someone is logged into a dialup modem. You need to worry about people
> running xmodem in a separate process from kermit, etc., etc.
OK, that's definately too many special conditions for kernel code.
Regards,
Richard....
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