Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!floyd!harpo!utah-cs!lepreau From: lepreau@utah-cs.UUCP (Jay Lepreau) Newsgroups: net.unix Subject: Re: mail locking Message-ID: <2587@utah-cs.UUCP> Date: Fri, 16-Mar-84 02:04:00 EST Article-I.D.: utah-cs.2587 Posted: Fri Mar 16 02:04:00 1984 Date-Received: Sat, 17-Mar-84 02:37:44 EST References: amd70.4430 Lines: 16 That's the whole point, that EVERY program that writes on /usr/spool/mail/user must observe the same locking protocol. Another problem with the locking as distributed (in 4.x bsd at least) is that the timeout in binmail is too short: only 30 seconds. After that binmail declares the lock defunct and merrily appends to the mail file. That can easily be exceeded on a not very loaded system by a user with a big mailbox, and many keep their boxes full of pending mail. As distributed, UCB Mail has the long timeout of 5 minutes, but that is the program that normally only needs a short timeout, as /bin/mail will append quickly. Anyway, I have extracted the relevant locking code into a module mlock.c containing, ah hah, mlock and mfree, which lock on /tmp. If people want I'll send it out (it's pretty minor, but it's done). I didn't use 4.2 file locking locking so it is portable. Jay Lepreau