On 2018-12-02 01:01, M. Buecher wrote:
I spent some time on how to keep backward compatibility for current
configurations.
The simplest solution would be to provide 2 systemd unit files:
1. An updated dnsmasq.service file for the main/default/standard
"instance", that reflects the fix for checking the configuration (see
attached file).
2. The new dnsmasq@.service file from the previous post for additional
instances.
This way nothing would change for people running just a single dnsmasq
instance. No need to rename or sym-link /etc/default/dnsmasq to
dnsmasq.main (or similar).
Still people could easily create extra instances with the new
dnsmasq@.service file and a corresponding
/etc/default/dnsmasq.<instance> file.
Got some time to look at the upstream repo.
Updated init.d script to current state plus renamed files for upstream
repo.
# This file has six functions:
# 1) to completely disable starting this dnsmasq instance
# 2) to set DOMAIN_SUFFIX by running `dnsdomainname`
# 3) to select an alternative config file
# by setting DNSMASQ_OPTS to --conf-file=<file>
# 4) to tell dnsmasq to read the files in /etc/dnsmasq.d for
# more configuration variables.
# 5) to stop the resolvconf package from controlling dnsmasq's
# idea of which upstream nameservers to use.
# 6) to avoid using this dnsmasq instance as the system's default resolver
# by setting DNSMASQ_EXCEPT="lo"
# For upgraders from very old versions, all the shell variables set
# here in previous versions are still honored by the init script
# so if you just keep your old version of this file nothing will break.
#DOMAIN_SUFFIX=`dnsdomainname`
#DNSMASQ_OPTS="--conf-file=/etc/dnsmasq.alt"
# Whether or not to run the dnsmasq daemon; set to 0 to disable.
ENABLED=1
# By default search this drop directory for configuration options.
# Libvirt leaves a file here to make the system dnsmasq play nice.
# Comment out this line if you don't want this. The dpkg-* are file
# endings which cause dnsmasq to skip that file. This avoids pulling
# in backups made by dpkg.
CONFIG_DIR=/etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new
# If the resolvconf package is installed, dnsmasq will use its output
# rather than the contents of /etc/resolv.conf to find upstream
# nameservers. Uncommenting this line inhibits this behaviour.
# Note that including a "resolv-file=<filename>" line in
# /etc/dnsmasq.conf is not enough to override resolvconf if it is
# installed: the line below must be uncommented.
#IGNORE_RESOLVCONF=yes
# If the resolvconf package is installed, dnsmasq will tell resolvconf
# to use dnsmasq under 127.0.0.1 as the system's default resolver.
# Uncommenting this line inhibits this behaviour.
#DNSMASQ_EXCEPT="lo"
#!/bin/sh
### BEGIN INIT INFO
# Provides: dnsmasq
# Required-Start: $network $remote_fs $syslog
# Required-Stop: $network $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Description: DHCP and DNS server
### END INIT INFO
# Don't exit on error status
set +e
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DAEMON=/usr/sbin/dnsmasq
NAME=dnsmasq
DESC="DNS forwarder and DHCP server"
INSTANCE="${2}"
# Most configuration options in /etc/default/dnsmasq are deprecated
# but still honoured.
ENABLED=1
if [ -r /etc/default/${NAME}${INSTANCE:+.${INSTANCE}} ]; then
. /etc/default/${NAME}${INSTANCE:+.${INSTANCE}}
fi
# Get the system locale, so that messages are in the correct language, and the
# charset for IDN is correct
if [ -r /etc/default/locale ]; then
. /etc/default/locale
export LANG
fi
# The following test ensures the dnsmasq service is not started, when the
# package 'dnsmasq' is removed but not purged, even if the dnsmasq-base
# package is still in place.
test -e /usr/share/dnsmasq/installed-marker || exit 0
test -x ${DAEMON} || exit 0
# Provide skeleton LSB log functions for backports which don't have LSB functions.
if [ -f /lib/lsb/init-functions ]; then
. /lib/lsb/init-functions
else
log_warning_msg () {
echo "${@}."
}
log_success_msg () {
echo "${@}."
}
log_daemon_msg () {
echo -n "${1}: ${2}"
}
log_end_msg () {
if [ "${1}" -eq 0 ]; then
echo "."
elif [ "${1}" -eq 255 ]; then
/bin/echo -e " (warning)."
else
/bin/echo -e " failed!"
fi
}
fi
# RESOLV_CONF:
# If the resolvconf package is installed then use the resolv conf file
# that it provides as the default. Otherwise use /etc/resolv.conf as
# the default.
#
# If IGNORE_RESOLVCONF is set in /etc/default/dnsmasq or an explicit
# filename is set there then this inhibits the use of the resolvconf-provided
# information.
#
# Note that if the resolvconf package is installed it is not possible to
# override it just by configuration in /etc/dnsmasq.conf, it is necessary
# to set IGNORE_RESOLVCONF=yes in /etc/default/dnsmasq.
if [ ! "${RESOLV_CONF}" ] &&
[ "${IGNORE_RESOLVCONF}" != "yes" ] &&
[ -x /sbin/resolvconf ]
then
RESOLV_CONF=/run/dnsmasq/resolv.conf
fi
for INTERFACE in ${DNSMASQ_INTERFACE}; do
DNSMASQ_INTERFACES="${DNSMASQ_INTERFACES} -i ${INTERFACE}"
done
for INTERFACE in ${DNSMASQ_EXCEPT}; do
DNSMASQ_INTERFACES="${DNSMASQ_INTERFACES} -I ${INTERFACE}"
done
if [ ! "${DNSMASQ_USER}" ]; then
DNSMASQ_USER="dnsmasq"
fi
# This tells dnsmasq to ignore DNS requests that don't come from a local network.
# It's automatically ignored if --interface --except-interface, --listen-address
# or --auth-server exist in the configuration, so for most installations, it will
# have no effect, but for otherwise-unconfigured installations, it stops dnsmasq
# from being vulnerable to DNS-reflection attacks.
DNSMASQ_OPTS="${DNSMASQ_OPTS} --local-service"
# If the dns-root-data package is installed, then the trust anchors will be
# available in ROOT_DS, in BIND zone-file format. Reformat as dnsmasq
# --trust-anchor options.
ROOT_DS="/usr/share/dns/root.ds"
if [ -f ${ROOT_DS} ]; then
DNSMASQ_OPTS="$DNSMASQ_OPTS `env LC_ALL=C sed -rne "s/^([.a-zA-Z0-9]+)([[:space:]]+[0-9]+)*([[:space:]]+IN)*[[:space:]]+DS[[:space:]]+/--trust-anchor=\1,/;s/[[:space:]]+/,/gp" $ROOT_DS | tr '\n' ' '`"
fi
start()
{
# Return
# 0 if daemon has been started
# 1 if daemon was already running
# 2 if daemon could not be started
# /run may be volatile, so we need to ensure that
# /run/dnsmasq exists here as well as in postinst
if [ ! -d /run/dnsmasq ]; then
mkdir /run/dnsmasq || { [ -d /run/dnsmasq ] || return 2 ; }
chown dnsmasq:nogroup /run/dnsmasq || return 2
fi
[ -x /sbin/restorecon ] && /sbin/restorecon /run/dnsmasq
start-stop-daemon --start --quiet --pidfile /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid --exec ${DAEMON} --test > /dev/null || return 1
start-stop-daemon --start --quiet --pidfile /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid --exec ${DAEMON} -- \
-x /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid \
${MAILHOSTNAME:+ -m ${MAILHOSTNAME}} \
${MAILTARGET:+ -t ${MAILTARGET}} \
${DNSMASQ_USER:+ -u ${DNSMASQ_USER}} \
${DNSMASQ_INTERFACES:+ ${DNSMASQ_INTERFACES}} \
${DHCP_LEASE:+ -l ${DHCP_LEASE}} \
${DOMAIN_SUFFIX:+ -s ${DOMAIN_SUFFIX}} \
${RESOLV_CONF:+ -r ${RESOLV_CONF}} \
${CACHESIZE:+ -c ${CACHESIZE}} \
${CONFIG_DIR:+ -7 ${CONFIG_DIR}} \
${DNSMASQ_OPTS:+ ${DNSMASQ_OPTS}} \
|| return 2
}
start_resolvconf()
{
# If interface "lo" is explicitly disabled in /etc/default/dnsmasq
# Then dnsmasq won't be providing local DNS, so don't add it to
# the resolvconf server set.
for interface in ${DNSMASQ_EXCEPT}; do
[ ${interface} = lo ] && return
done
# Also skip this if DNS functionality is disabled in /etc/dnsmasq.conf
if grep -qs '^port=0' /etc/dnsmasq.conf; then
return
fi
if [ -x /sbin/resolvconf ] ; then
echo "nameserver 127.0.0.1" | /sbin/resolvconf -a lo.${NAME}${INSTANCE:+.${INSTANCE}}
fi
return 0
}
stop()
{
# Return
# 0 if daemon has been stopped
# 1 if daemon was already stopped
# 2 if daemon could not be stopped
# other if a failure occurred
start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid --name ${NAME}
}
stop_resolvconf()
{
if [ -x /sbin/resolvconf ] ; then
/sbin/resolvconf -d lo.${NAME}${INSTANCE:+.${INSTANCE}}
fi
return 0
}
status()
{
# Return
# 0 if daemon is running
# 1 if daemon is dead and pid file exists
# 3 if daemon is not running
# 4 if daemon status is unknown
start-stop-daemon --start --quiet --pidfile /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid --exec ${DAEMON} --test > /dev/null
case "${?}" in
0) [ -e "/run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid" ] && return 1 ; return 3 ;;
1) return 0 ;;
*) return 4 ;;
esac
}
case "${1}" in
start)
test "${ENABLED}" != "0" || exit 0
log_daemon_msg "Starting ${DESC}" "${NAME}${INSTANCE:+.${INSTANCE}}"
start
case "${?}" in
0)
log_end_msg 0
start_resolvconf
exit 0
;;
1)
log_success_msg "(already running)"
exit 0
;;
*)
log_end_msg 1
exit 1
;;
esac
;;
stop)
stop_resolvconf
if [ "${ENABLED}" != "0" ]; then
log_daemon_msg "Stopping ${DESC}" "${NAME}${INSTANCE:+.${INSTANCE}}"
fi
stop
RETVAL="${?}"
if [ "${ENABLED}" = "0" ]; then
case "${RETVAL}" in
0) log_daemon_msg "Stopping ${DESC}" "${NAME}${INSTANCE:+.${INSTANCE}}"; log_end_msg 0 ;;
esac
exit 0
fi
case "${RETVAL}" in
0) log_end_msg 0 ; exit 0 ;;
1) log_warning_msg "(not running)" ; exit 0 ;;
*) log_end_msg 1; exit 1 ;;
esac
;;
checkconfig)
${DAEMON} --test ${CONFIG_DIR:+ -7 ${CONFIG_DIR}} ${DNSMASQ_OPTS:+ ${DNSMASQ_OPTS}} >/dev/null 2>&1
RETVAL="${?}"
exit ${RETVAL}
;;
restart|force-reload)
test "${ENABLED}" != "0" || exit 1
${DAEMON} --test ${CONFIG_DIR:+ -7 ${CONFIG_DIR}} ${DNSMASQ_OPTS:+ ${DNSMASQ_OPTS}} >/dev/null 2>&1
if [ ${?} -ne 0 ]; then
NAME="configuration syntax check"
RETVAL="2"
else
stop_resolvconf
stop
RETVAL="${?}"
fi
log_daemon_msg "Restarting ${DESC}" "${NAME}${INSTANCE:+.${INSTANCE}}"
case "${RETVAL}" in
0|1)
sleep 2
start
case "${?}" in
0)
log_end_msg 0
start_resolvconf
exit 0
;;
*)
log_end_msg 1
exit 1
;;
esac
;;
*)
log_end_msg 1
exit 1
;;
esac
;;
status)
log_daemon_msg "Checking ${DESC}" "${NAME}${INSTANCE:+.${INSTANCE}}"
status
case "${?}" in
0) log_success_msg "(running)" ; exit 0 ;;
1) log_success_msg "(dead, pid file exists)" ; exit 1 ;;
3) log_success_msg "(not running)" ; exit 3 ;;
*) log_success_msg "(unknown)" ; exit 4 ;;
esac
;;
dump-stats)
kill -s USR1 `cat /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid`
;;
systemd-start-resolvconf)
start_resolvconf
;;
systemd-stop-resolvconf)
stop_resolvconf
;;
systemd-exec)
# /run may be volatile, so we need to ensure that
# /run/dnsmasq exists here as well as in postinst
if [ ! -d /run/dnsmasq ]; then
mkdir /run/dnsmasq || { [ -d /run/dnsmasq ] || return 2 ; }
chown dnsmasq:nogroup /run/dnsmasq || return 2
fi
exec ${DAEMON} -x /run/dnsmasq/${NAME}${INSTANCE:+.${INSTANCE}}.pid \
${MAILHOSTNAME:+ -m ${MAILHOSTNAME}} \
${MAILTARGET:+ -t ${MAILTARGET}} \
${DNSMASQ_USER:+ -u ${DNSMASQ_USER}} \
${DNSMASQ_INTERFACES:+ ${DNSMASQ_INTERFACES}} \
${DHCP_LEASE:+ -l ${DHCP_LEASE}} \
${DOMAIN_SUFFIX:+ -s ${DOMAIN_SUFFIX}} \
${RESOLV_CONF:+ -r ${RESOLV_CONF}} \
${CACHESIZE:+ -c ${CACHESIZE}} \
${CONFIG_DIR:+ -7 ${CONFIG_DIR}} \
${DNSMASQ_OPTS:+ ${DNSMASQ_OPTS}}
;;
*)
echo "Usage: /etc/init.d/${NAME} {start|stop|restart|force-reload|dump-stats|status}" >&2
exit 3
;;
esac
exit 0
[Unit]
Description=dnsmasq - A lightweight DHCP and caching DNS server
Requires=network.target
Wants=nss-lookup.target
Before=nss-lookup.target
After=network.target
[Service]
Type=forking
PIDFile=/run/dnsmasq/dnsmasq.pid
# Test the config file and refuse starting if it is not valid.
ExecStartPre=/etc/init.d/dnsmasq checkconfig
# We run dnsmasq via the /etc/init.d/dnsmasq script which acts as a
# wrapper picking up extra configuration files and then execs dnsmasq
# itself, when called with the "systemd-exec" function.
ExecStart=/etc/init.d/dnsmasq systemd-exec
# The systemd-*-resolvconf functions configure (and deconfigure)
# resolvconf to work with the dnsmasq DNS server. They're called like
# this to get correct error handling (ie don't start-resolvconf if the
# dnsmasq daemon fails to start).
ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf
ExecStop=/etc/init.d/dnsmasq systemd-stop-resolvconf
ExecReload=/bin/kill -HUP $MAINPID
[Install]
WantedBy=multi-user.target
[Unit]
Description=dnsmasq (%i) - A lightweight DHCP and caching DNS server
Requires=network.target
Wants=nss-lookup.target
Before=nss-lookup.target
After=network.target
[Service]
Type=forking
PIDFile=/run/dnsmasq/dnsmasq.%i.pid
# Test the config file and refuse starting if it is not valid.
ExecStartPre=/etc/init.d/dnsmasq checkconfig "%i"
# We run dnsmasq via the /etc/init.d/dnsmasq script which acts as a
# wrapper picking up extra configuration files and then execs dnsmasq
# itself, when called with the "systemd-exec" function.
ExecStart=/etc/init.d/dnsmasq systemd-exec "%i"
# The systemd-*-resolvconf functions configure (and deconfigure)
# resolvconf to work with the dnsmasq DNS server. They're called like
# this to get correct error handling (ie don't start-resolvconf if the
# dnsmasq daemon fails to start).
ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf "%i"
ExecStop=/etc/init.d/dnsmasq systemd-stop-resolvconf "%i"
ExecReload=/bin/kill -HUP $MAINPID
[Install]
WantedBy=multi-user.target
