#!/bin/sh
# Copyright (C) 2017 Dmitry Bogatov <KAction@gnu.org>

# Author: Dmitry Bogatov <KAction@gnu.org>

# This program 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 program 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.

# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

set -e

# rescan and invoke-rc.d actions are done only if runit is init
is_runit () {
	[ -f  /run/runit.stopit ]
}

is_installed () {
	[ -f  /sbin/runit ]
}

# No-Op if the service is not enabled
# sv can't send signals to a disabled service
is_enabled () {
	[ -h /etc/service/"$NAME" ]
}

sv_warn () {
	echo "warning: sv: failed to signal $NAME"
	true
}

# workaround for races as in #919296
ok_pipe () {
	[ -p "/etc/sv/$NAME/supervise/ok" ]
}

postinst () {
	local action="${1}" previous="${2:-}"

	# create supervise links at runtime, only if runit is installed
	mkdir -p /run/runit/supervise
	if [ -e /lib/runit/make_svlinks ]; then
		/lib/runit/make_svlinks "$NAME"
	fi

	# loguser transition: to be removed when the transition is done 
	# we do ths before enable to avoid races
	# old loguser is 'runit-log', new is '_runit-log'
	# 'current' and 'lock' files in the run directory must be owned by
	# the new loguser
	if [ "${ENABLE}" = yes ] && \
		[ -f "/var/log/runit/$NAME/current" ] ; then
		loguser="$(stat --format '%U' /var/log/runit/$NAME/current)"
		if [ "${loguser}" = "runit-log" ]; then
			sv d "/etc/sv/$NAME/log" >/dev/null || true
			chown _runit-log:adm /var/log/runit/$NAME/current
			chown _runit-log:adm /var/log/runit/$NAME/lock
		fi
	fi

	# It is important to not override local admin
	# decision (see #899242 and 942323 ).
	if [ "${ENABLE}" = yes ] && \
		[ ! -h "/etc/runit/runsvdir/default/.$NAME" ] ; then
		# avoid infinte loop of symlinks
		if [ ! -h "/etc/runit/runsvdir/default/$NAME" ]; then
			ln -sf "/etc/sv/$NAME" "/etc/runit/runsvdir/default/$NAME"
			if is_runit ; then
				# always force a rescan after enable
				kill -s ALRM 1
			fi
		fi
	fi
	# ENABLE=no is always a no-op

	# Upgrade will changes destination of /etc/sv/{name}/supervise symlink from
	# /var/* to /run/*. If service was running, it important that its supervise
	# directory is still accessible via /etc/sv/{name}/supervise symlink.
	#
	# This code must be removed once there are no more packages with
	# /etc/sv/{name}/supervise -> /var/lib/runit/supervise/{name}

	old="/var/lib/runit/supervise/${NAME}" 
	new="/run/runit/supervise/${NAME}"
	if [ -d "${old}" ] ; then
		ln -sf "${old}" "${new}"
	fi

	old="/var/lib/runit/log/supervise/${NAME}" 
	new="/run/runit/supervise/${NAME}.log"
	if [ -d "${old}" ] ; then
		ln -sf "${old}" "${new}"
	fi

	# loguser transition: to be removed when the transition is done
	# we do this after enable to reduce chance of races
	if [ "${ENABLE}" = yes ] && \
		[ -f "/etc/sv/$NAME/log/run" ] ; then
		if is_installed && is_enabled ; then
			sv u "/etc/sv/$NAME/log" >/dev/null || true
		fi
	fi

	#invoke-rc.d
	if is_runit && is_enabled ; then
		if [ "${action}" = 'configure' ] || [ "${action}" = 'abort-upgrade' ] || \
			[ "${action}" = 'abort-deconfigure' ] || [ "${action}" = 'abort-remove' ] ; then
			if [ "${ONUPGRADE}" = restart ] && [ -n "${previous}" ] && ok_pipe ; then
				sv restart ${NAME} || sv_warn
			elif [ "${ONUPGRADE}" = reload ] && [ -n "${previous}" ] && ok_pipe ; then
				sv reload ${NAME} || sv_warn
			elif  ok_pipe ; then
				# ONUPGRADE=stop || ONUPGRADE=nostop
				# ONUPGRADE= restart || reload and [ ! -n "${previous}" ]
				sv start ${NAME} || sv_warn
			else
				return 0
			fi
		fi
	fi
}

prerm () {
	local action="${1}"
	# invoke-rc.d
	if is_runit && is_enabled ; then
		if [ "${ONUPGRADE}" = stop ] && ok_pipe ; then
			sv stop ${NAME} || sv_warn
		elif [ "${action}" = 'remove' ] && ok_pipe ; then
			# ONUPGRADE=restart || ONUPGRADE=nostop
			sv stop ${NAME} || sv_warn
		else
			return 0
		fi
	fi	
}

postrm () {
	local action="${1}"

	if [ "${action}" != 'purge' ] && [ "${action}" != 'remove' ] ; then
	    return
	fi

	# When "ENABLE=no" the $NAME link is an admin decision
	# so we don't remove it.
	# Links in other runsvdirs is responsibility of administrator.
	if [ "${action}" = 'remove' ] && [ "${ENABLE}" = yes ] ; then
		rm -f "/etc/runit/runsvdir/default/$NAME"
	fi

	# If runscript was never invoked, there will be no files
	# in this directory, and `dpkg' will remove it. In this case,
	# we have nothing to do.
	for supervise in "/var/lib/runit/supervise/$NAME" \
	                 "/var/lib/runit/log/supervise/$NAME" \
	                 "/etc/sv/$NAME/supervise" \
	                 "/etc/sv/$NAME/log/supervise"; do
		if [ -d "$supervise" ] ; then

			# Actually only `down' may be absent, but it does not
			# matter.

			for file in control lock ok pid stat status down ; do
				rm -f "$supervise/$file"
			done

			# It should be empty now. If it is not, it means that
			# system administrator put something there. It is very
			# stupid, but will of user is sacred, and directory is
			# left as-is in such case.
			#
			# NOTE: Non-POSIX option is used. The day coreutils will
			# no longer be essential, it will require a fix.
			if [ -h "$supervise" ]; then
				rm "$supervise"
			else
				rmdir --ignore-fail-on-non-empty "$supervise"
			fi
		fi
	done

	if [ "${action}" = 'purge' ] ; then
		rm -f "/etc/runit/runsvdir/default/$NAME"
		rm -f "/etc/runit/runsvdir/default/.$NAME"
		readonly logdir="/var/log/runit/${NAME}"
		if [ -d "${logdir}" ] ; then
			rm -r "${logdir}"
		fi
	fi
}

"$@"
# vim: sw=4:et