56 lines
2.3 KiB
Markdown
56 lines
2.3 KiB
Markdown
# Construct Server
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Construct is the executable running `libircd`. This application provides an
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interface for the server administrator to start, stop, configure and locally
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communicate with the daemon. It sets up an `asio::io_service` which is passed
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to `libircd`, then it sets up signal handling, and then it runs the ios event
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loop until commanded to exit.
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This program executes in the foreground. It does not "daemonize" anymore with a
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`fork()` etc. You are free to use your shell to execute or move the program
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to the background, or simply use a `tmux` or `screen`. Construct will output
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the libircd log to stdout and stderr by default.
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### Signals
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Construct handles certain POSIX signals and their behavior is documented
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below. Prolonged ownership of any specific signal handler is not taken by
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libircd; only out here in the construct executable. libircd only makes
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cooperative use of signals: registering and deregistering any handlers
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stackfully in such a way that it is no concern to users of the library.
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* Signal handling is accomplished through `boost::asio`'s mechanism which
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installs a handler to intercept the signal's delivery and posts it to the
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event loop for execution at the next event slice. This is how signal safety
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is achieved. Furthermore, according to boost docs, when signals are used
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this way they can be compatible with windows environments.
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##### SIGQUIT
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A `ctrl-\` to Construct will cleanly shut down the server. It will not generate
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a coredump.
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##### SIGINT
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A `ctrl-c` to Construct will bring up the command line console interface. It
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will not halt the daemon. Log messages will be suppressed while the console
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is waiting for input, but service is still continuing in the background.
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##### SIGHUP
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A "HangUP" to Construct is only relevant to the command line console, and
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signals it to close like an `EOF`. The legacy functionality for reloading
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server configuration et al is moved to `SIGUSR1`.
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##### SIGUSR1
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This signal commands the server to reload and refresh various aspects of its
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configuration and running state.
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##### SIGCONT
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This signal is used to notify the server that execution has resumed after an
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unexpected gap. We call `ircd::cont()` after receiving this signal. Examples
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for when the server benefits from calling `ircd::cont()` are: after a previous
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stop signal, debugging, or ACPI suspend and resume, etc.
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