chrony: add ntp hotplug provider script

When the service is started, wait for the clock to be synchronized for
up to 5 minutes and provide the stratum action once for ntp hotplug
scripts.

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>

net/chrony/Makefile

@@ -85,6 +85,7 @@ define Package/chrony/install
 	$(INSTALL_DIR) $(1)/usr/sbin/
 	$(INSTALL_BIN) $(PKG_BUILD_DIR)/chronyd $(1)/usr/sbin
 	$(INSTALL_BIN) $(PKG_BUILD_DIR)/chronyc $(1)/usr/bin
+	$(INSTALL_BIN) ./files/chrony.ntp-hotplug $(1)/usr/sbin/chrony-hotplug
 	$(INSTALL_DIR) $(1)/etc/init.d
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_DIR) $(1)/etc/chrony

net/chrony/files/chrony.ntp-hotplug

@@ -0,0 +1,6 @@
+#!/bin/sh
+# Wait for sync for up to 5 minutes and notify other services
+
+/usr/bin/chronyc waitsync 300 1 0.0 1 || exit 0
+
+ubus call hotplug.ntp call '{ "env": [ "ACTION=stratum" ] }'

net/chrony/files/chronyd.init

@@ -4,6 +4,7 @@
 START=15
 USE_PROCD=1
 PROG=/usr/sbin/chronyd
+HOTPLUG=/usr/sbin/chrony-hotplug
 CONFIGFILE=/etc/chrony/chrony.conf
 INCLUDEFILE=/var/etc/chrony.d/10-uci.conf
 RTCDEVICE=/dev/rtc0
@@ -79,6 +80,10 @@ start_service() {
 	procd_set_param file $INCLUDEFILE
 	procd_close_instance
 
+	procd_open_instance
+	procd_set_param command $HOTPLUG
+	procd_close_instance
+
 	config_load chrony
 	mkdir -p $(dirname $INCLUDEFILE)