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From: chris@umcp-cs.UUCP (Chris Torek)
Newsgroups: net.emacs
Subject: Re: Question about GNU Emacs rmail
Message-ID: <1706@umcp-cs.UUCP>
Date: Fri, 27-Sep-85 23:28:44 EDT
Article-I.D.: umcp-cs.1706
Posted: Fri Sep 27 23:28:44 1985
Date-Received: Wed, 2-Oct-85 08:58:31 EDT
References: <365@eneevax.UUCP> <3746@topaz.RUTGERS.EDU> <357@faron.UUCP>
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 19

The proper way to fix the mail system---and this has already been
implemented in 4.3BSD---is to use flock() on /usr/spool/mail/$USER
files, and teach /bin/mail and all the user interface programs to
obey this new locking protocol.

Using this scheme, /usr/spool/mail need not be writable, which
avoids quite a number of security hassles.  Also, it is much more
efficient than linking files to $USER.lock.  If all readers use
shared locks, and all writers use exclusive locks, your mailbox
remains consistent.

Just this afternoon I helped Don Hopkins fix up Gnumacs' movemail
program.  The new version should be in your net.sources.  Compile
with `-DUSE_FLOCK', or `-UUSE_FLOCK' for the old behaviour, or edit
the #define line.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@maryland