Overall Administration: sacadm Command

The sacadm command is the top level of the SAF. The sacadm command primarily is used to add and remove port monitors such as ttymon and listen. Other sacadm functions include listing the current status of port monitors and administering port monitor configuration scripts.

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.

SAC Initialization Process

The following steps summarize what happens when SAC is first started:

1. The SAC program is spawned by init at run level two.

2. The SAC program reads /etc/saf/_safconfig, the per-system configuration script.

3. The SAC program reads /etc/saf/_sactab, the SAC administrative file.

4. The SAC program forks a child process for each port monitor it starts.

5. Each port monitor reads /etc/saf/pmtag/_config, the per-port monitor configuration script.