From: Adam Shostack <adam@homeport.org>
Date: Mon, 15 Jul 1996 05:38:39 +0800
To: mcarpent@mailhost.tcs.tulane.edu
Subject: Re: Execution of signed scripts received by e-mail
In-Reply-To: <199607141042.FAA01300@Dusk.obscure.net>
Message-ID: <199607141903.OAA20371@homeport.org>
MIME-Version: 1.0
Content-Type: text


Matt Carpenter wrote:

| If I am reading the procmail docs correctly, then the following recipe
| should create a lockfile called 'emscrypt.lock' which will prevent more than
| one instance of the script from being run at a time
| 
| :0:emscrypt
| ^ Subject.*SQUEAMISH OSSIFRAGE
| |/PATH/emscrypt
| 
| I agree it would be better if emscrypt used its own locks on the timestamp
| files.  However, it is my understanding (someone please correct me if I am
| wrong) that there is no simple way to provide file locking in Perl that is
| portable across the various flavours of Unix (see the descriptions of the
| fcntl and flock functions on p. 144-145 of the Camel book).  So I haven't
| tried to implement locking from within emscrypt yet.  Of course, if these
| functions are available on the majority of machines (anyone?) then I should
| probably use them.

	procmail includes a program called lockfile, which is based on
its thorough as hell lock mechanism tests.  If you're calling from
procmail, you might decide to require lockfile.

Adam


-- 
"It is seldom that liberty of any kind is lost all at once."
					               -Hume