Autossh Startup Script for Multiple Tunnels

#!/bin/bash
#
# autossh . Startup script for autossh

# chkconfig: 2345 25 40
# description: Maintain persistent SSH tunnels
# processname: autossh
# pidfile: /var/run/autossh.pid

# Copyright 2012 - Jean-Sebastien Morisset - https://surniaulula.com/
#
# https://surniaulula.com/2012/12/10/autossh-startup-script-for-multiple-tunnels/
#
# This script is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 3 of the License, or (at your option) any later
# version.
#
# This script is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details at http://www.gnu.org/licenses/.

# Changelog:
#
# 2013/06/21 - Reset the $forward_list variable at the start() to prevent the
# accumulation of ports for each config loop. Also added support for socks
# proxies. Thanks to Chris for pointing out the issue in the comments.

# Source function library
. /etc/init.d/functions

RETVAL=0
prog="autossh"
autossh="/usr/bin/autossh"

[ ! -d /var/run/$prog ] && mkdir -p /var/run/$prog

start() {
	config="$1"
	cfname=`basename $config`
	forward_list=""

	# make sure we have a config file
	if [ ! -f "$config" ]
	then
		failure
		echo "$prog $cfname: $config missing"
		return 1
	fi

	. $config

	# make sure all variables have been defined in config
	for var in \
		ServerAliveInterval ServerAliveCountMax StrictHostKeyChecking \
		LocalUser IdentityFile RemoteUser RemoteHost RemotePort
	do eval "
		if [ -z \$$var ]
		then
			failure
			echo \"$prog $cfname: $var variable empty\"
			return 1
		fi
		"
	done

	if [ ${#ForwardPort[*]} -eq 0 ]
	then
		failure
		echo "$prog $cfname: ForwardPort array empty"
		return 1
	fi

	for fwd in "${ForwardPort[@]}"
	do
		case "$fwd" in
		D\ *:*|R\ *:*:*:*|L\ *:*:*:*) forward_list+="-$fwd " ;;
		*)	failure
			echo "$prog $cfname: $fwd format unknown"
			return 1
			;;
		esac
	done

	# define the pidfile variable for autossh (created by autossh)
	# check if pidfile already exists -- don't start another instance if pidfile exists
	AUTOSSH_PIDFILE="/var/run/$prog/$cfname.pid"
	if [ -e $AUTOSSH_PIDFILE ]
	then
		failure
		echo "$prog $cfname: $AUTOSSH_PIDFILE already exists"
		return 1
	fi

	echo -n "Starting $prog $cfname: "

	# before switching-users, make sure pidfile is created and user has write permission
	touch $AUTOSSH_PIDFILE
	chown $LocalUser $AUTOSSH_PIDFILE

	# start autossh as the user defined in the config file
	# the pidfile must be re-defined in the new environment
	su - $LocalUser -c "
		AUTOSSH_PIDFILE=$AUTOSSH_PIDFILE;
		AUTOSSH_PORT=0;
		export AUTOSSH_PIDFILE AUTOSSH_PORT;
		$autossh -q -N -p $RemotePort \
		-i $IdentityFile \
		-o ServerAliveInterval=$ServerAliveInterval \
		-o ServerAliveCountMax=$ServerAliveCountMax \
		-o StrictHostKeyChecking=$StrictHostKeyChecking \
		$forward_list $RemoteUser@$RemoteHost -f;"

	# check to make sure pidfile was created
	if [ ! -f $AUTOSSH_PIDFILE ]
	then
		failure
		echo "`basename $AUTOSSH_PIDFILE` not created"
		return 1
	fi

	success
	echo
	touch /var/lock/subsys/$prog
}

stop() {
	config="$1"
	# if no config names (on the command-line), stop all autossh processes
	if [ -z "$config" ]
	then
		echo -n "Stopping all $prog: "
		killproc $autossh
		RETVAL=$?
		echo
		if [ $RETVAL -eq 0 ]
		then
			rm -f /var/lock/subsys/$prog
			rm -f /var/run/$prog/*.pid
		fi
	else
		cfname="`basename $config`"
		pidfile="/var/run/$prog/$cfname.pid"
		if [ ! -f $pidfile ]
		then
			failure
			echo "$prog $cfname: $pidfile missing"
			return 1
		else
			echo -n $"Stopping $prog $cfname: "
			killproc -p "/var/run/$prog/$cfname.pid" "$prog $cfname"
			RETVAL=$?
			echo
			[ $RETVAL -eq 0 ] && rm -f /var/run/$prog/$cfname.pid
		fi
	fi
	return $RETVAL
}

# save the action name, and shift the command-line array
# all remaining command-line arguments could be config names
action="$1"
shift

case "$action" in
start)
	if [ -z "$1" ]
	then
		# if no config names on the command-line, start all /etc/autossh/ configs found
		for config in `echo /etc/$prog/${cfname:='*'}`
		do $action $config; done
	else
		# start only the config files specified on the command-line
		for cfname in "$@"
		do $action /etc/$prog/$cfname; done
	fi
	;;
stop)
	if [ -z "$1" ]
	then
		# if no config names on the command-line, stop all autossh processes
		$action
	else
		# stop only the config files specified on the command-line
		for cfname in "$@"
		do $action /etc/$prog/$cfname; done
	fi
	;;
restart)
	# re-execute this script, with the stop and start action names instead
	$0 stop "$@"
	$0 start "$@"
	;;
status)
	if [ -z "$1" ]
	then
		# if no config names on the command-line, show all autossh pids
		status $autossh
		RETVAL=$?
	else
		# only show the status of config files specified on the command-line
		for cfname in "$@"
		do
			config="/etc/$prog/$cfname"
			# if the config file is missing, echo an error message
			if [ -f $config ]
			then
				cfname="`basename $config`"
				pidfile="/var/run/$prog/$cfname.pid"
				# if the pidfile is missing, echo an error message
				if [ -f $pidfile ]
				then
					status -p "$pidfile" "$prog $cfname"
					RETVAL=$?
				else
					echo "$pidfile missing"
					RETVAL=1
				fi
			else
				echo "$config missing"
				RETVAL=1
			fi
		done
	fi
	;;
*)
	echo "Usage: $0 {start|stop|restart|status} {config names...}"
	RETVAL=1
	;;
esac
exit $RETVAL