A TCP/IP socket to listen on the RSP port is created in rsp_init (), and its file descriptor stored in rsp.server_fd. As a variant, if the port is configured to be 0, the socket uses the port specified for the or1ksim-rsp service.

The setup uses standard POSIX calls to establish the socket and associate it with a TCP/IP port. The interface is set to be non-blocking and marked as a passive port (using a call to listen ()), with at most one outstanding client request. There is no meaning to the server handling more than one client GDB connection.

The main RSP handler function handle_rsp () checks that the server port is still open. This may be closed if there is a serious error. In the present implementation, handle_rsp () gives up at this point, but a richer implementation could try reopening a new server port.