Managing mail with MMDF

Mailbox locking problems

You may experience mailbox locking problems, signified by these error messages:

mail: Cannot read lock file '/usr/spool/mail/username'
Or, if mail is delivered to $HOME/.mailbox, the message is
```
   mail: Cannot read lock file 'username/.mailbox'
```

This error message can be found in /usr/mmdf/log/msg.log and chan.log:

   10/ 5 10:15:06 local 0913:  [SYSERR (13) Permission denied]
           	        open of /usr/spool/mail/root
   
   10/ 5 10:15:06 local 0913:  [SYSERR (13) Permission denied]
            		can't open mailbox '/usr/spool/mail/root'

The MMDF configuration sets MLCKTYPE to all (MLCKTYPE allows you to specify the locking protocol for MMDF to use when locking users' mailboxes).

The MLCKTYPE parameter is useful if the users on the system use third party mail user agents (MUAs) that use a lock file that is different from the standard System V lock file.

This mailbox locking problem occurs when MMDF fails to unlink the /usr/spool/mail/username.lock or /tmp/username.mlk file, which is created to lock the mailbox. If mail is delivered to $HOME/.mailbox, the lock file is /tmp/.mailbox.lock. A subsequent fcntl(M) (kernel file locking) process returns with a permission denied error because it cannot lock the mailbox.

To resolve the locking problem, log in as root and enter this at the root prompt:

/usr/mmdf/bin/cleanlck

NOTE: You can use MLCKTYPE (in /usr/mmdf/mmdftailor) to specify other locking protocols. See ``The mmdftailor file''. However, changing locking protocols is not recommended.