To implement a port monitor, several generic requirements must be met. This section summarizes these requirements. In addition to the port monitor itself, an administrative command must be supplied.
When a port monitor is started, it expects an initial execution environment in which:
It has no file descriptors open
It cannot be a process group leader
It has an entry in /etc/utmp of type LOGIN_PROCESS
An environment variable, ISTATE
, is set to "enabled" or "disabled" to indicate the port monitor's correct initial state
An environment variable, PMTAG
, is set to the port monitor's assigned tag
The directory that contains the port monitor's administrative files is its current directory
The port monitor is able to create private files in the directory /var/saf/tag, where tag is the port monitor's tag