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To: "Karl Denninger, MCSNet" <karl@mcs.com>
cc: nate@sri.MT.net, softweyr@xmission.com, security@FreeBSD.org
Subject: Re: FreeBSD's /var/mail permissions 
In-reply-to: Your message of "Fri, 07 Jun 1996 16:48:01 CDT."
             <m0uS9Nx-000IDOC@venus.mcs.com> 
Date: Fri, 07 Jun 1996 15:36:43 -0700
From: Paul Traina <pst@shockwave.com>
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Karl,

I'm saying that mail.local uses flock().  It does not respect lock files
created by other programs.  If you want to do something weird because NFS
doesn't support locks, be my guest.  But if you think it works out of the
box, you're wrong.

Paul

  From: "Karl Denninger, MCSNet" <karl@mcs.com>
  Subject: Re: FreeBSD's /var/mail permissions
  > Mail locking, to be effective, must be soley performed through the use of
  > the flock() call on the mail file itself.
  > 
  > Locking schemes relying on other mechanisms are not effective.
  > 
  > Sorry.
  
  Mail locking, to be effective, must *work across machines* so that NFS
  mounts of the mail directory work.
  
  flock() cannot be trusted to work in this environment, and in fact doesn't
  even attempt to work on FreeBSD.
  
  Does this mean we should give up on using mail?
  
  --
  --
  Karl Denninger (karl@MCS.Net)| MCSNet - The Finest Internet Connectivity
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