ELM under OSx4.1 Pyramids

[Carl S. Gutekunst]

(Cross posted to comp.mail.uucp because of the general issue of lock files.)

In article <476 at tness1.UUCP> unsegh at swbt.com (Greg Hackney) writes:
>Do the OSx 4.1 uucp programs use flock() ?

I just reread this, and I'm not sure if you mean mailers or UUCP. For mailers
see my previous message in comp.sys.pyramid.

UUCP uses lock files, like it always has. Too many things would break if it
were changed to use flock(). The difference between universes is that:

- ucb (4.3BSD UUCP) uses a separate subdirectory, /usr/spool/uucp/LCK, to hold
  lock files. The contents of the lock file is the PID, in binary, of the
  uucico process that created the lock. The use of the subdirectory is a com-
  pile-time option, and I chose to put it in since that allows you to use 755
  modes in /usr/spool/uucp, and 777 modes on /usr/spool/uucp/LCK.

- old att (SVR2.2 UUCP) puts the lock files directly in /usr/spool/uucp. Their
  contents is identical to that of 4.3BSD. Note that OSx 4.1 is shipped with
  SVR2.2 UUCP hidden away in /usr/.attold, and will soon be moved to an option
  tape.

- new att (Basic Networking Utilities, aka HoneyDanBer) puts locks in the di-
  rectory /usr/spool/locks. The contents of the lock files is the uucico PID
  in ASCII, right justified in a 10-character field, terminated by a newline.

I modified both 4.3BSD and HDB to recognize each others lock files, and set up
OSx 4.1 with a symbolic link from /usr/spool/locks to /usr/spool/uucp/LCK. So
you can run them concurrently. (At least one site, though, has complained that
they stomp each other when run out of the same /usr/spool/uucp. That site set
up separate /usr/spool/.attuucp and /usr/spool/.ucbuucp directories, joined at
/usr/spool/uucp by a conditional symbolic link.)

<csg>