To Deliver Messages to Programs Using the Pipe Channel

Users might want incoming mail passed to a program instead of to their mailbox. For example, users might want their incoming mail sent to a mail sorting program. The pipe channel performs delivery of messages using per-user, site-supplied programs.

To facilitate program delivery, you must first register programs as able to be invoked by the pipe channel. Do this by using the imsimta program utility. This utility gives a unique name to each command that you register as able to be invoked by the pipe channel. End users can then specify the method name as a value of their mailprogramdeliveryinfo LDAP attribute.

For example, to add a UNIX command myprocmail as a program that can be invoked by a user, you would first register the command by using the imsimta program utility as shown in the following example. This example registers a program called myprocmail that executes the program procmail with the arguments -d username and executes as the user:

imsimta program -a -m myprocmail -p procmail -g "-d %s" -e user

Make sure the executable exists in the programs directory msg_svr_base/data/site-programs. Make sure also that the execute permissions are set to “others.”

To enable a user to access the program, the user’s LDAP entry must contain the following attributes and values:

maildeliveryoption: program 
mailprogramdeliveryinfo: myprocmail

For more information about the imsimta program utility, see the Sun Java System Messaging Server 6 2005Q4 Administration Reference.

Alternative delivery programs must conform to the following exit code and command-line argument restrictions:

Exit Code Restrictions. Delivery programs invoked by the pipe channel must return meaningful error codes so that the channel knows whether to dequeue the message, deliver for later processing, or return the message.

If the subprocess exits with an exit code of 0 (EX_OK), the message is presumed to have been delivered successfully and is removed from the MTA queues. If it exits with an exit code of 71, 74, 75, or 79 (EX_OSERR, EX_IOERR, EX_TEMPFAIL, or EX_DB), a temporary error is presumed to have occurred and delivery of the message is deferred. If any other exit code is returned, then the message will be returned to its originator as undeliverable. These exit codes are defined in the system header file sysexits.h.

Command Line Arguments. Delivery programs can have any number of fixed arguments as well as the variable argument, %s, representing the user name for programs executed by the user or username+domain for programs executed by the postmaster, “inetmail.” For example, the following command line delivers a recipient’s mail using the program procmail:

/usr/lib/procmail -d %s