IRC bot written in POSIX Shell using netcat

poudriere-irc.sh

#! /bin/sh
#
# Copyright (c) 2013 Bryan Drewery <bdrewery@FreeBSD.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
set -ef

NICK="poudriere"
CHANNEL="#poudriere"
SERVER="irc.sucks.net"
PORT=6667
VERSION="Poudriere build bot (https://fossil.etoilebsd.net/poudriere/)"
REALNAME="${VERSION}"
STATUS_SOCKET=/tmp/poudriere.sock
HOSTNAME="$(hostname -s)"

CTCP=$(echo -e "\001")

send() {
	echo "[->] $@"
	echo "$@" >> ${OUT}
}

send_ctcp_reply() {
	local nick keyword msg

	echo "[CTCP->] $@"
	nick="$1"
	keyword="$2"
	shift 2
	msg="$@"
	notice ${nick} "${CTCP}${keyword} ${msg}${CTCP}"
}

notice() {
	local nick msg

	nick="$1"
	shift
	msg="$@"

	send "NOTICE ${nick} :${msg}"
}

privmsg() {
	local nick msg

	nick="$1"
	shift
	msg="$@"

	send "PRIVMSG ${nick} :${msg}"
}

handle_ctcp() {
	local nick msg keyword

	nick="$1"
	shift

	# Trim out \001
	msg="${@}"
	msg="${msg%${CTCP}}"
	msg="${msg#${CTCP}}"
	set -- "${msg}"

	keyword="$1"
	shift
	msg="$@"

	case "${keyword}" in
		VERSION)
			send_ctcp_reply ${nick} ${keyword} "${VERSION}"
			return 0
			;;
	esac

}

handle_privmsg() {
        local from msg nick target reply_target

        from="${1#:}"
        nick="${from%!*}"
        target="${3}"
        shift 3
        msg="${@#:}"

        case "${msg}" in
                ${CTCP}*${CTCP})
                        handle_ctcp ${nick} "${msg}"
                        return 0
                        ;;
        esac

        #[<-] :nick!user@host PRIVMSG #channel :text
        #[<-] :nick!user@host PRIVMSG nick :text
        reply_target="${target}"
        [ "${target}" = "${MYNICK}" ] && reply_target="${nick}"

        echo "<${from}> ${msg}"

        case "${msg}" in
                "!poudriere status")
                        poudriere status | while read line; do
                                privmsg ${reply_target} "${nick}: [${HOSTNAME}] ${line}"
                        done
                        ;;
                *)
                        ;;
        esac

}

recv() {
	echo "[<-] $@"

	# [<-] PING :irc.servercentral.net
	case $1 in
		:*)
			;;
		PING)
			send "PONG $2"
			return 0
			;;
	esac

	case $2 in
		PRIVMSG)
			handle_privmsg "$@"
			return 0
			;;
		433) # :server 433 * test :Nickname is already in use.
			send "NICK ${4}_"
			return 0
			;;
		001) # :server 001 test :Welcome to IRC
			MYNICK="$3"
			send "JOIN ${CHANNEL} ${CHANNEL_KEY}"
			return 0
			;;
		*)
			;;
	esac
}

poudriere_socket() {
	rm -f ${STATUS_SOCKET}
	nc -klU ${STATUS_SOCKET} | while read cmd mastername line; do
		case "$cmd" in
			status)
				privmsg "${CHANNEL}" \
				    "[${HOSTNAME}][${mastername}] Status: ${line}"
				;;
		esac
	done
}

OUT=$(mktemp)

# http://stackoverflow.com/a/15557994/285734
usr1_handler() {
        exit
}

exit_handler() {
        [ -n "${OUT}" ] && rm -f ${OUT} 2>/dev/null
        # Kill children and nc(1)
        kill -USR1 -$$
}

trap exit_handler EXIT INT TERM
trap usr1_handler USR1

main() {
	[ -n "${PASS}" ] && send "PASS ${PASS}"
	send "NICK ${NICK}"
	send "USER ${NICK} localhost ${SERVER} :${REALNAME}"

	# Start the listen socket for poudriere
	poudriere_socket &

	tail -F ${OUT} | nc ${SERVER} ${PORT} | while read raw; do
		raw="${raw%$'\n'}"
		raw="${raw%$'\r'}"
		recv ${raw}
	done
}

main

This is a prototype for poudriere IRC support. It will be moved to https://fossil.etoilebsd.net/poudriere/.

A root process writes to /tmp/poudriere.sock with nc(1) as well which relays the information to IRC:

echo "status ${MASTERNAME} ${status}" | nc -U /tmp/poudriere.sock