Service Access Controller: SAC Program

The Service Access Controller program (SAC) oversees all port monitors. A system automatically starts SAC upon entering multiuser mode.

When SAC is invoked, it first looks for, and interprets, each system's configuration script, by which SAC customizes its environment. The modifications made to the SAC environment are inherited by all the “children” of the SAC. This inherited environment might be modified by the children.

After it has interpreted the per-system configuration script, the SAC program reads its administrative file and starts the specified port monitors. For each port monitor, SAC runs a copy of itself (SAC forks a child process). Each child then interprets its per-port monitor configuration script, if such a script exists.

Any modifications to the environment specified in the per-port monitor configuration script affect the port monitor and will be inherited by all its children. Finally, the child process runs the port monitor program using the command found in the SAC administrative file.