#!/bin/sh -e
#
# 2011 Nico Schottelius (nico-cdist at schottelius.org)
# 2012 Giel van Schijndel (giel plus cdist at mortis dot eu)
# 2020 Dennis Camera (dennis.camera at ssrq-sds-fds.ch)
#
# This file is part of cdist.
#
# cdist 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.
#
# cdist 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 cdist. If not, see <http://www.gnu.org/licenses/>.
#
#
# Retrieve the status of a package - parses opkg output
#

readonly __type_path=${__object%%${__object_id}*}
test -d "${__type_path}" || { echo 'Cannot determine __type_path' >&2; exit 1; }
readonly LOCKFILE="${__type_path:?}/.cdist_opkg.lock"

if command -v flock >/dev/null 2>&1
then
	# use flock (if available) on FD 9
	_lock() {
		exec 9<>"${LOCKFILE:?}"
		flock -x 9
		echo $$>&9
	}
	_unlock() {
		:>"${LOCKFILE:?}"
		flock -u 9
		exec 9<&-
	}
else
	# fallback to mkdir if flock is missing
	_lock() {
		until mkdir "${LOCKFILE:?}.dir" 2>/dev/null
		do
			while test -d "${LOCKFILE}.dir"
			do
				# DEBUG:
				# printf 'Locked by PID: %u\n' "$(cat "${LOCKFILE}.dir/pid")"
				sleep 1
			done
		done
		echo $$ >"${LOCKFILE:?}.dir/pid"
	}
	_unlock() {
		test -d "${LOCKFILE}.dir" || return 0
		if test -s "${LOCKFILE}.dir/pid"
		then
			test "$(cat "${LOCKFILE}.dir/pid")" = $$ || return 1
			rm "${LOCKFILE:?}.dir/pid"
		fi
		rmdir "${LOCKFILE:?}.dir"
	}
fi


if test -f "${__object}/parameter/name"
then
	pkg_name=$(cat "${__object}/parameter/name")
else
	pkg_name=$__object_id
fi


# NOTE: We need to lock parallel execution of type explorers and code-remote
# because opkg will try to acquire the OPKG lock (usually /var/lock/opkg.lock)
# using lockf(2) for every operation.
# It will not wait for the lock but terminate with an error.
# This leads to incorrect 'absent notpresent' statuses when parallel execution
# is enabled.
trap _unlock EXIT
_lock


# Except opkg failing, if package is not known / installed
if opkg status "${pkg_name}" 2>/dev/null \
	| grep -q -e '^Status: [^ ][^ ]* [^ ][^ ]* installed$'
then
	echo 'present'
elif opkg info "${pkg_name}" 2>/dev/null | grep -q .
then
	echo 'absent notpresent'
else
	echo 'absent'
fi