Accessing CP special messages through uevent environment variables

A uevent for a CP special message contains environment variables that you can use to access the message.

SMSG_ID
Specifies the message prefix. The SMSG_ID environment variable is always set to APP, which is the prefix that is assigned to the smsgiucv_app device driver.
SMSG_SENDER
Specifies the z/VM user ID that sent the CP special message.

Use SMSG_SENDER in udev rules for filtering the z/VM user ID if you want to accept CP special messages from different senders. All alphabetic characters in the z/VM user ID are uppercase characters.

SMSG_TEXT
Contains the message text of the CP special message. The APP prefix and leading white spaces are removed.