Subject: sharing mailboxes

From: Clive McDowell <[email-masked]>
Date: Wed, 23 Jul 2003 12:01:47 +0100

Folks,

I'm attempting to set up a mechanism on a sparc Solaris 8 platform to allow a user e.g. a secretary to have access to another user's mailbox. I have approached this by setting both users to be the same group and setting the INBOX file (mbx format) to have group rw permissions. Mailboxes are in /folders/${username}. I'm working with Outlook XP as a client (not through my choice) and by setting the root folder path to /folders I can display and subscribe to the other user's INBOX file. On a test machine I have complete rw access to the second mailbox but when I try the same thing on the machine in service I encounter problems. I can subscribe to the INBOX file OK but access is another matter. If I can see the contents of the folder at all any attempt to interact with it results in an error message e.g. Unable to lock mailbox. I have tried the same exercise with Netscape and the same thing happens. The only difference between the test and service machines is the level of activity. Both have the latest version of imapd installed. Any ideas as to why these locking problems should occur on a busy machine?

Thanks,

Clive McDowell

Information Services
The Queen's University of Belfast

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From: Mark Crispin <[email-masked]>
Date: Mon, 18 Aug 2003 17:26:36 -0700 (Pacific Daylight Time)

Sorry for the delay in responding; I was on vacation.

What is the exact error message that you are getting?

On Wed, 23 Jul 2003, Clive McDowell wrote:
> I'm attempting to set up a mechanism on a sparc Solaris 8 platform to
> allow a user e.g. a secretary to have access to another user's mailbox.
> I have approached this by setting both users to be the same group and
> setting the INBOX file (mbx format) to have group rw permissions.
> Mailboxes are in /folders/${username}. I'm working with Outlook XP as a
> client (not through my choice) and by setting the root folder path to
> /folders I can display and subscribe to the other user's INBOX file. On
> a test machine I have complete rw access to the second mailbox but when
> I try the same thing on the machine in service I encounter problems. I
> can subscribe to the INBOX file OK but access is another matter. If I
> can see the contents of the folder at all any attempt to interact with
> it results in an error message e.g. Unable to lock mailbox. I have tried
> the same exercise with Netscape and the same thing happens. The only
> difference between the test and service machines is the level of
> activity. Both have the latest version of imapd installed. Any ideas as
> to why these locking problems should occur on a busy machine?

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.

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From: Clive McDowell <[email-masked]>
Date: Tue, 19 Aug 2003 09:57:17 +0100

----- Original Message ----- 
From: "Mark Crispin" <[email-masked]>
To: "Clive McDowell" <[email-masked]>
Cc: "c-client" <[email-masked]>
Sent: Tuesday, August 19, 2003 1:26 AM
Subject: Re: sharing mailboxes

> What is the exact error message that you are getting?

Mark,

hope you enjoyed your break. I figured this one out shortly after I sent the query. We are using Exim as our MTA software and it uses flock and fcntrl by default. On the busy service machine the lock files created by flock were not being removed hence no access via a mail client to the mailbox. I was able to resolve the problem by configuring exim to use only fcntrl.

regards,

Clive McDowell

Information Services

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From: Mark Crispin <[email-masked]>
Date: Tue, 19 Aug 2003 14:53:42 -0700 (Pacific Daylight Time)

I don't understand this.  flock doesn't create any files, and there should
be locking between imapd and the MTA.

On Tue, 19 Aug 2003, Clive McDowell wrote:
> hope you enjoyed your break. I figured this one out shortly after I sent
> the query. We are using Exim as our MTA software and it uses flock and
> fcntrl by default. On the busy service machine the lock files created by
> flock were not being removed hence no access via a mail client to the
> mailbox. I was able to resolve the problem by configuring exim to use
> only fcntrl.

-- Mark --

---

From: Clive McDowell <[email-masked]>
Date: Wed, 20 Aug 2003 08:49:35 +0100

> be locking between imapd and the MTA.

Sorry - I meant lockf. Exim was creating a lock file owned by the local user it was delivering to. If this file wasn't removed then access by a different user with appropriate group permissions did not work. The second user had insufficient permissions to remove the lock file and access the inbox. Obviously there was no problem with the owner accessing the mailbox. Configuring Exim not to use lockf cured the problem.

Clive McDowell

Information Services