Agent Tcl architecture

Agent Tcl has two components.

• The first component is a special Tcl interpreter that executes the Tcl agents. The interpreter is implemented in two distinct layers.
  • A modified Tcl core that allows the capture and restoration of the internal state of an executing Tcl script
  • A Tcl extension package that provides the agent commands such as jump
• The second component is a server that runs on each machine to which agents can be sent. The server is implemented as two cooperating processes.
  • The socket watcher process watches a TCP/IP port for incoming agents, messages and connection requests. The socket watcher enforces the security policies, executes the incoming agents and passes the messages and connection requests on to the agent tables process.
  • The agent tables process keeps track of which agents are executing on its machine and buffers the messages and connection requests.

All communication is via TCP/IP and BSD sockets.

The architecture is shown in the figure below. The interpreter is on the left and the server is on the right.