#!/bin/bash

# Copyright (C) 2009-2014 Timo Weingärtner <timo@tiwe.de>
#
# This file is part of openssh-known-hosts.
#
# openssh-known-hosts 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.
#
# openssh-known-hosts 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 openssh-known-hosts. If not, see <http://www.gnu.org/licenses/>.

set -euC

CONFDIR=${CONFDIR:-/etc/openssh-known-hosts}
PLUGIN_PATH=${PLUGIN_PATH:-/usr/local/share/openssh-known-hosts/plugins:/usr/share/openssh-known-hosts/plugins}
CACHEDIR=${CACHEDIR:-/var/cache/openssh-known-hosts}
LOCK=${LOCK:-/var/lock/openssh-known-hosts}
OUTFILE=${OUTFILE:-/var/lib/openssh-known-hosts/ssh_known_hosts}

path_search () {
	search="$1"
	shift
	local IFS
	IFS=:
	set -- $@
	if [[ ${search} =~ / ]]; then
		echo "${search}"
		return 0
	fi
	for path; do
		if [ -f "${path}/${search}" ]; then
			echo "${path}/${search}"
			return 0
		fi
	done
	echo "'${search}' not found in '$*'!" >&2
	exit 127
}

cleanup () {
	rm -f "${OUTFILE}.new"
	kill "${LOCKPID}"
	lockfile-remove "${LOCK}"
}

if [ $# -eq 1 ] && [ "$1" = "-f" ]; then
	fail=1
else
	fail=''
fi

trap cleanup EXIT

lockfile-create "${LOCK}"
lockfile-touch "${LOCK}" &
LOCKPID="$!"

mkdir -p "${CACHEDIR}"
cd "${CACHEDIR}"

find -mindepth 2 -maxdepth 2 -type f -name new -delete

run-parts --list "${CONFDIR}/sources/" | while read sourcefile; do
	source=${sourcefile##*/}
	mkdir -p "${source}"
	(
		set -a
		cd "${source}"
		. "${sourcefile}"
		$(path_search "$PLUGIN" "$PLUGIN_PATH") >| log 2>&1 || {
			exitcode=$?
			rm -f new
			ignore=''
			for e in ${EXIT_IGNORE:-0}; do
				if [[ $e = "$exitcode" ]]; then
					ignore=1
					break
				fi
			done
			if [ -z "$ignore" -o "$fail" ]; then
				echo "${source} exited with code ${exitcode}, log follows:"
				cat log
				echo
			fi
			if [ "$fail" ]; then
				exit 1
			fi
		} >&2
	) || exit 1
	if [ -e "${source}/new" ]; then
		mv "${source}/new" "${source}/current"
	fi
	if [ -e "${source}/current" ]; then
		if [ -e "${sourcefile}.filter" ]; then
			if [[ ${source}/filtered -ot ${source}/current ]] || [[ ${source}/filtered -ot ${sourcefile}.filter ]]; then
				mapfile -t filter < "${sourcefile}.filter"
				for i in "${!filter[@]}"; do
					if [[ ${filter[$i]} =~ ^($|#) ]]; then
						unset filter[$i]
					fi
				done
				while read hostlist rest; do
					IFS=, read -a hostarray <<<"$hostlist"
					new_hostlist=''
					for host in "${hostarray[@]}"; do
						for rule in "${filter[@]}"; do
							if [[ ${host} =~ ${rule#* } ]]; then
								if [[ ${rule%% *} =~ ^[aopy] ]]; then
									new_hostlist="${new_hostlist}${host},"
								fi
								break
							fi
						done
					done
					[ "$new_hostlist" ] || continue
					echo "${new_hostlist%,} ${rest}"
				done < "${source}/current" | sort -u >| "${source}/filtered.new"
				mv "${source}/filtered.new" "${source}/filtered"
			fi
			cat "${source}/filtered" >&3
		else
			sort -u "${source}/current" >&3
		fi
	fi
done 3>| "${OUTFILE}.new"

if cmp -s "${OUTFILE}" "${OUTFILE}.new"; then
	rm "${OUTFILE}.new"
else
	mv "${OUTFILE}.new" "${OUTFILE}"
fi

# clean up cache dirs of vanished sources
for d in *; do
	[ -d "$d" ] || continue
	[ -e "${CONFDIR}/sources/$d" ] || rm -fr "$d"
done

# vim:set ft=sh: