systemd-resolved.in

#!/bin/sh
# Copyright (c) 2009-2023 Roy Marples
# All rights reserved

# systemd-resolved subscriber for resolvconf

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

[ -f "@SYSCONFDIR@"/resolvconf.conf ] || exit 0
. "@SYSCONFDIR@/resolvconf.conf" || exit 1
[ -n "$systemd_resolved_conf" ] || exit 0
[ -n "$RESOLVCONF" ] || eval "$(@SBINDIR@/resolvconf -v)"
NL="
"

conf="# Generated by resolvconf$NL"
conf="${conf}$NL"
conf="${conf}[Resolve]$NL"

# We emit blank values to force them to reset on SIGHUP
conf="${conf}DNS=$NAMESERVERS$NL"

# Once https://github.com/systemd/systemd/issues/20485 is resolved,
# we could do something with the per domain name servers
domains=
for d in $DOMAINS; do
	domain=${d%%:*}
	domains="${domains}${domains:+ }$domain"
done
conf="${conf}Domains=$domains$NL"

# Try to ensure that config dirs exist
if command -v config_mkdirs >/dev/null 2>&1; then
	config_mkdirs "$systemd_resolved_conf"
else
	@SBINDIR@/resolvconf -D "$systemd_resolved_conf"
fi

if [ ! -f "$systemd_resolved_conf" ] || \
	[ "$(cat "$systemd_resolved_conf")" != "$(printf %s "$conf")" ]
then
	printf %s "$conf" >"$systemd_resolved_conf"
	pid=$(pidof systemd-resolved)
	if [ -n "$pid" ]; then
		kill -HUP $pid
	fi
fi