PXED threaded operations

The last piece of the PXED server is actually a set of operations that are used to keep things running. Since the PXED server is threaded, these operations are actually set up as threads that occasionally do things to make sure everything is together.

The first thread, the main thread, handles the SRC requests (such as startsrc, stopsrc, lssrc, traceson, and refresh). This thread also coordinates all operations that affect all threads and handles signals. For example,

• A SIGHUP (-1) causes a refresh of all databases in the configuration file.
• A SIGTERM (-15) causes the server to gracefully stop.

The other thread processes packets. Depending on the server type, there can one or two threads. One thread listens on port 67 and the second one listens to port 4011. Each of these can handle a request from a client.