TCPS-708 — Log level incremented in response to a received signal
The log level (maximum severity code which will be logged) can be set between I (6, LOG_INFO) to F (9, FULL_DEBUG). When the proxy receives signal SIGUSR1, the log level is incremented by one, i.e., less severe messages will be logged in addition to currently logged types of messages. Signalling the parent process changes the log level also in all child processes.