init

#!/bin/sh

### BEGIN INIT INFO
# Provides:           nginx
# Required-Start:     $local_fs $remote_fs $network $syslog $named
# Required-Stop:      $local_fs $remote_fs $network $syslog $named
# Default-Start:      2 3 4 5
# Default-Stop:       0 1 6
# Short-Description:  nginx LSB init script
# Description:        nginx Linux Standards Base compliant init script.
### END INIT INFO


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                              Variables
# ----------------------------------------------------------------------------------------------------------------------


# The name of the daemon.
readonly NAME=nginx

# Arguments that should be passed to the executable.
DAEMON_ARGS=

# The path in which to search for the daemon.
readonly PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

# Absolute path to the PID file.
PIDFILE=$(printf -- '%s/run/%s.pid' "$([ -d /run ] || printf -- /var)" "${NAME}")

# Will be set by /lib/init/vars.sh
VERBOSE=no


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                            Error Codes
# ----------------------------------------------------------------------------------------------------------------------


readonly EC_INVALID_ARGUMENT=2
readonly EC_SUPER_USER_ONLY=4
readonly EC_DAEMON_NOT_FOUND=5
readonly EC_RELOADING_FAILED=150
readonly EC_RESTART_STOP_FAILED=151
readonly EC_RESTART_START_FAILED=152
readonly EC_START_FAILED=153
readonly EC_STOP_FAILED=154


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                              Functions
# ----------------------------------------------------------------------------------------------------------------------


# Exit the script with an error code.
die()
{
	log_end_msg $1
	exit $1
}

# End the script.
end()
{
	[ "${VERBOSE}" != no ] && log_end_msg 0
	exit 0
}

# Display failure message.
fail()
{
	log_failure_msg "${NAME}" "$1"
}

# Display informational message.
info()
{
	[ "${VERBOSE}" != no ] && log_daemon_msg "${NAME}" "$1"
}

# Display success message.
ok()
{
	[ "${VERBOSE}" != no ] && log_success_msg "${NAME}" "$1"
}

# Display warning message.
warn()
{
	log_warning_msg "${NAME}" "$1"
}

# Print usage string.
usage()
{
	printf 'Usage: %s {start|stop|restart|try-restart|reload|force-reload|status}\n' "$0"
}

###
# Check privileges of caller. This will automatically exit if the caller has insufficient privileges.
#
# RETURN:
#   0 - sufficient privileges
###
check_privileges()
{
	if [ $(id -u) -ne 0 ]
	then
		fail 'super user only!'
		die ${EC_SUPER_USER_ONLY}
	fi
}

###
# Reloads the service.
#
# RETURN:
#   0 - successfully reloaded
#   1 - reloading failed
###
reload_service()
{
	start-stop-daemon --stop --signal HUP ${SSD_OPTIONS}
}

###
# Starts the service.
#
# RETURN:
#   0 - successfully started
#   1 - starting failed
###
start_service()
{
	start-stop-daemon --start ${SSD_OPTIONS} -- ${DAEMON_ARGS}
}

###
# Stops the service.
#
# RETURN:
#   0 - successfully stopped
#   1 - stopping failed
###
stop_service()
{
	start-stop-daemon --stop --signal QUIT --retry=TERM/30/KILL/5 ${SSD_OPTIONS}
}


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                               Includes
# ----------------------------------------------------------------------------------------------------------------------


# Load the VERBOSE setting and other rcS variables plus any script defaults.
for INCLUDE in /lib/init/vars.sh /etc/default/${NAME}
	do [ -r "${INCLUDE}" ] && . "${INCLUDE}"
done

# Make all variables which are allowed to be altered by the defaults file as read-only.
readonly DAEMON_ARGS
readonly PIDFILE


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                              Bootstrap
# ----------------------------------------------------------------------------------------------------------------------


# Load the LSB log_* functions.
INCLUDE=/lib/lsb/init-functions
if [ -r "${INCLUDE}" ]
then
	. "${INCLUDE}"
else
	printf '%s: unable to load LSB functions, cannot start service.\n' "${NAME}" 1>&2
	exit ${EC_DAEMON_NOT_FOUND}
fi

# Make sure only one argument was passed to the script.
if [ $# -ne 1 ]
then
	if [ $# -lt 1 -o "$1" = '' ]
		then fail 'action not specified.'
		else fail 'too many arguments.'
	fi
	usage 1>&2
	die ${EC_INVALID_ARGUMENT}
fi
readonly ACTION="$1"

# Check if daemon is a recognized program and get absolute path.
readonly DAEMON=$(command -v "${NAME}")
if [ ! -x "${DAEMON}" ]
then
	if [ "${ACTION}" = 'stop' ]
	then
		warn 'executable not found: stop request ignored'
		end
	else
		fail "executable not found: cannot ${ACTION} service"
		die ${EC_DAEMON_NOT_FOUND}
	fi
fi

# Default options for start-stop-daemon command.
readonly SSD_OPTIONS="--quiet --oknodo --pidfile "${PIDFILE}" --exec "${DAEMON}" --name "${NAME}""

# Determine the service's status.
#
#   0 = Program is running
#   1 = Program is not running and the PID file exists.
#   2 = Program is not running and a LOCK file exists.
#   3 = Program is not running.
#   4 = Unable to determine status.
start-stop-daemon --status ${SSD_OPTIONS} 2>/dev/null 1>/dev/null
readonly STATUS=$?


# ----------------------------------------------------------------------------------------------------------------------
#                                                                                                           Handle Input
# ----------------------------------------------------------------------------------------------------------------------


case "$1" in

	# Reload the configuration, if the service is running, otherwise do nothing.
	force-reload|reload)
		if [ ${STATUS} -eq 0 ]
		then
			info 'reloading configuration ...'
			reload_service || die ${EC_RELOADING_FAILED}
		else
			info 'service not running, nothing to be done.'
		fi
	;;

	# Restart the service, if the service is already running, otherwise start the service.
	restart)
		if [ ${STATUS} -eq 0 ]
		then
			info 'restarting service ...'
			stop_service || die ${EC_RESTART_STOP_FAILED}
			sleep 0.1
		fi
		start_service || die ${EC_RESTART_START_FAILED}
	;;

	# Start the service, do nothing if it is already running.
	start)
		if [ ${STATUS} -eq 0 ]
		then
			ok 'already started.'
		else
			info 'starting ...'
			start_service || die ${EC_START_FAILED}
		fi
	;;

	# Print service status.
	#
	# This can be invoked by any user and has different exit codes:
	#   0 - running and OK
	#   1 - dead and /var/run PID file exists
	#   2 - dead and /var/lock lock file exists
	#   3 - not running
	#   4 - unknown
	status)
		status_of_proc "${DAEMON}" "${NAME}" || exit $?
	;;

	# Stop the service, do nothing if it is already stopped.
	stop)
		if [ ${STATUS} -eq 0 ]
		then
			info 'stopping ...'
			stop_service || die ${EC_STOP_FAILED}
		else
			info 'already stopped.'
		fi
	;;

	# Restart the service, if the service is already running, otherwise do nothing.
	try-restart)
		check_privileges
		if [ ${STATUS} -eq 0 ]
		then
			info 'restarting service ...'
			stop_service || die ${EC_RESTART_STOP_FAILED}
			sleep 0.1
			start_service || die ${EC_RESTART_START_FAILED}
		else
			info 'service not running, nothing to be done.'
		fi
	;;

	-h|--help)
		usage
	;;

	*)
		fail "action '${ACTION}' not recognized."
		usage 1>&2
		exit ${EC_INVALID_ARGUMENT}
	;;

esac

end