Bug#11094: Policy should mention that serial lines require UUCP-style locking
Hi,
Generally, the basic idea is that each program that uses a serial port
writes a file in /var/lock with the name, as I recall, LCK..portname.
Inside that file, I believe, is stored the PID of that process. The
file is removed when the port is no loinger used. Various serial port
programs use this mechanism. I believe you could probably find out
the mechanics by reading the source of one of them; perhaps minicom or
some such. I used to know the exact mechanics of it but my memory is
somewhat dim on the subject now. It also allows apps to co-exist
peacefully with things like *getty.
-- John
Julian Gilbey <J.D.Gilbey@qmw.ac.uk> writes:
> John,
>
> You originally proposed the following amendment to policy:
>
> There is no mention of the UUCP-style locking required for serial
> lines to prevent multiple communications programs from attempting to
> use the same line at once. For a brief description of UUCP-style
> serial locking, see the discussion for bug #10575.
>
> Now bug #10575 no longer exists, and I know nothing about this
> subject. It is clear that this is an important matter and should not
> just be dropped (as Ian pointed out recently).
>
> Could you please give more details of what the policy should say in
> this regard?
>
> Julian
>
> --
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>
> Julian Gilbey, Dept of Maths, QMW, Univ. of London. J.D.Gilbey@qmw.ac.uk
> Debian GNU/Linux Developer, see http://www.debian.org/~jdg
> Donate free food to the world's hungry: see http://www.thehungersite.com/
--
John Goerzen <jgoerzen@complete.org> www.complete.org
Sr. Software Developer, Progeny Linux Systems, Inc. www.progenylinux.com
#include <std_disclaimer.h> <jgoerzen@progenylinux.com>
Reply to: