Messages in this thread | | | From | (david parsons) | Subject | Re: >256 ptys (previous subject line was garbage) | Date | 8 Jun 1998 19:03:27 -0700 |
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In article <linux.kernel.199806090036.KAA08187@vindaloo.atnf.csiro.au>, Richard Gooch <Richard.Gooch@atnf.CSIRO.AU> wrote: >tytso@mit.edu writes: >> Date: Fri, 5 Jun 1998 12:59:59 +0200 (MET DST) >> From: Peter Svensson <petersv@df.lth.se> >> >> I am not familiar with the reasons for using major/minor-pair for >> locking so I don't know if another solution is feasable. Do you have >> any pointers for additional reading? :-) >> >> 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.)
____ david parsons \bi/ I [heart] mgetty \/
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