chronyd: don't start it when running on Hyper-V

This is a bit ugly as we copied and then modified the chronyd init.d
script as shipped in the package.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

alpine/Dockerfile

@@ -54,6 +54,7 @@ COPY packages/hvtools/etc /etc/
 COPY packages/hvtools/hv_get_dhcp_info /sbin/
 COPY packages/hvtools/hv_get_dns_info /sbin/
 COPY packages/hvtools/hv_set_ifconfig /sbin/
+COPY packages/chronyd/etc /etc/
 COPY packages/userns/etc /etc/
 COPY packages/userns/groupadd /usr/sbin
 COPY packages/userns/useradd /usr/sbin

alpine/packages/chronyd/etc/init.d/chronyd

@@ -0,0 +1,73 @@
+#!/sbin/openrc-run
+# Copyright 1999-2007 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: /var/cvsroot/gentoo-x86/net-misc/chrony/files/chronyd.rc,v 1.8 2007/03/22 14:32:09 tove Exp $
+
+description="NTP daemon"
+
+depend() {
+	need net
+	after firewall
+	provide ntp-client ntp-server
+	use dns
+}
+
+checkconfig() {
+	# Note that /etc/chrony/chrony.keys is *NOT* checked. This
+	# is because the user may have specified another key
+	# file, and we don't want to force the user to use that
+	# exact name for the key file.
+	if [ ! -f "${CFGFILE}" ] ; then
+		eerror "Please create ${CFGFILE} and the"
+		eerror "chrony key file (usually /etc/chrony/chrony.keys)"
+		eerror "by using the"
+		eerror ""
+		eerror "        chrony.conf.example"
+		eerror "        chrony.keys.example"
+		eerror ""
+		eerror "files (from the documentation directory)"
+		eerror "as templates."
+		return 1
+	else
+		# Actually, I tried it, and chrony seems to ignore the pidfile
+		# option. I'm going to leave it here anyway, since you never
+		# know if it might be handy
+		PIDFILE=`awk '/^ *pidfile/{print $2}' "${CFGFILE}"`
+	fi
+	return 0
+}
+
+setxtrarg() {
+	if [ -c /dev/rtc ]; then
+		grep -q '^rtcfile' "${CFGFILE}" && ARGS="${ARGS} -s"
+	fi
+	grep -q '^dumponexit$' "${CFGFILE}" && ARGS="${ARGS} -r"
+	return 0
+}
+
+start() {
+	[ -d /sys/bus/vmbus ] && exit 0
+	checkconfig || return $?
+	setxtrarg
+
+	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/chronyd.pid
+
+	ebegin "Starting chronyd"
+	start-stop-daemon --start --quiet \
+		--exec /usr/sbin/chronyd \
+		--pidfile "${PIDFILE}" \
+		-- -f "${CFGFILE}" ${ARGS}
+	eend $? "Failed to start chronyd"
+}
+
+stop() {
+	[ -d /sys/bus/vmbus ] && exit 0
+	checkconfig || return $?
+
+	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/chronyd.pid
+
+	ebegin "Stopping chronyd"
+	start-stop-daemon --stop --quiet \
+		--pidfile "${PIDFILE}"
+	eend $? "Failed to stop chronyd"
+}