construct/construct

Construct Server

Construct is the executable running libircd. This application provides an interface for the server administrator to start, stop, configure and locally communicate with the daemon. It sets up an asio::io_service which is passed to libircd, then it sets up signal handling, and then it runs the ios event loop until commanded to exit.

This program executes in the foreground. It does not "daemonize" anymore with a fork() etc. You are free to use your shell to execute or move the program to the background, or simply use a tmux or screen. Construct will output the libircd log to stdout and stderr by default.

Signals

Construct handles certain POSIX signals and their behavior is documented below. Prolonged ownership of any specific signal handler is not taken by libircd; only out here in the construct executable. libircd only makes cooperative use of signals: registering and deregistering any handlers stackfully in such a way that it is no concern to users of the library.

• Signal handling is accomplished through boost::asio's mechanism which installs a handler to intercept the signal's delivery and posts it to the event loop for execution at the next event slice. This is how signal safety is achieved. Furthermore, according to boost docs, when signals are used this way they can be compatible with windows environments.

SIGQUIT

A ctrl-\ to Construct will cleanly shut down the server. It will not generate a coredump.

SIGINT

A ctrl-c to Construct will bring up the command line console interface. It will not halt the daemon. Log messages will be suppressed while the console is waiting for input, but service is still continuing in the background.

SIGHUP

A "HangUP" to Construct is only relevant to the command line console, and signals it to close like an EOF. The legacy functionality for reloading server configuration et al is moved to SIGUSR1.

SIGUSR1

This signal commands the server to reload and refresh various aspects of its configuration and running state.

SIGCONT

This signal is used to notify the server that execution has resumed after an unexpected gap. We call ircd::cont() after receiving this signal. Examples for when the server benefits from calling ircd::cont() are: after a previous stop signal, debugging, or ACPI suspend and resume, etc.