Fix dhcp ntp on osx

1. Upstream issue in Alpine that default directory is not used.
2. dhcp appends ntp servers, so delete default first.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

alpine/Makefile

@@ -6,7 +6,7 @@ initrd.img: Dockerfile mkinitrd.sh init $(ETCFILES)
 	$(MAKE) -C kernel
 	$(MAKE) -j -C packages
 	tar cf - \
-	  Dockerfile etc init mkinitrd.sh \
+	  Dockerfile etc usr init mkinitrd.sh \
 	  -C kernel usr etc sbin lib -C .. \
 	  -C packages/proxy usr sbin etc -C ../.. \
 	  -C packages/transfused sbin etc -C ../.. \

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

@@ -46,10 +46,20 @@ setxtrarg() {
 }
 
 start() {
-	[ "$(mobyplatform)" = "windows" ] && exit 0
-
-	[ "$(mobyplatform)" = "aws" ] && \
-		sed -i -e "s/^server [^ ]\+/server 0.amazon.pool.ntp.org/g" /etc/chrony/chrony.conf
+	case "$(mobyplatform)" in
+		"windows")
+			exit 0
+		;;
+		"mac")
+			sed -i '/server pool.ntp.org/d' /etc/chrony/chrony.conf
+		;;
+		"aws")
+			sed -i -e "s/^server [^ ]\+/server 0.amazon.pool.ntp.org/g" /etc/chrony/chrony.conf
+		;;
+		"azure")
+			# TODO needs an ntp solution
+		;;
+	esac
 
 	checkconfig || return $?
 	setxtrarg

alpine/packages/chronyd/etc/udhcpc/post-bound/chronyd

@@ -1,26 +0,0 @@
-#!/bin/sh
-
-if [ "x$interface" != "xeth0" ] ; then exit 0 ; fi
-
-if cat /proc/cmdline | grep -q '\bntp=gateway\b' ; then
-    if [ -n "$router" ] ; then
-        logger -t udhcpc "ntp=gateway used, using \$router=$router as \$ntpsrv"
-        server="$router trust"
-    else
-        logger -t udhcpc "ntp=gateway used but \$router not provided"
-    fi
-elif [ -n "$ntpsrv" ] ; then
-    # Just take the first
-    set -- $ntpsrv
-    server="$1"
-fi
-
-if [ -z "$server" ] ; then
-    logger -t udhcpc "No NTP server via DHCP"
-    exit 0
-fi
-
-sed -i -e "s/^server [^ ]\+/server $server/g" /etc/chrony/chrony.conf
-
-logger -t udhcpc "Restarting chronyd with server $server"
-service -q chronyd conditionalrestart

alpine/usr/lib/dhcpcd/dhcpcd-hooks/50-ntp.conf

@@ -0,0 +1,141 @@
+# Sample dhcpcd hook script for NTP
+# It will configure either one of NTP, OpenNTP or Chrony (in that order)
+# and will default to NTP if no default config is found.
+
+# Like our resolv.conf hook script, we store a database of ntp.conf files
+# and merge into /etc/ntp.conf
+
+# You can set the env var NTP_CONF to override the derived default on
+# systems with >1 NTP client installed.
+# Here is an example for OpenNTP
+#   dhcpcd -e NTP_CONF=/usr/pkg/etc/ntpd.conf
+# or by adding this to /etc/dhcpcd.conf
+#   env NTP_CONF=/usr/pkg/etc/ntpd.conf
+# or by adding this to /etc/dhcpcd.enter-hook
+#   NTP_CONF=/usr/pkg/etc/ntpd.conf
+# To use Chrony instead, simply change ntpd.conf to chrony.conf in the
+# above examples.
+
+: ${ntp_confs:=ntp.conf ntpd.conf chrony.conf}
+: ${ntp_conf_dirs=/etc /usr/pkg/etc /usr/local/etc /etc/chrony}
+ntp_conf_dir="$state_dir/ntp.conf"
+
+# If NTP_CONF is not set, work out a good default
+if [ -z "$NTP_CONF" ]; then
+	for d in ${ntp_conf_dirs}; do
+		for f in ${ntp_confs}; do
+			if [ -e "$d/$f" ]; then
+				NTP_CONF="$d/$f"
+				break 2
+			fi
+		done
+	done
+	[ -e "$NTP_CONF" ] || NTP_CONF=/etc/ntp.conf
+fi
+
+# Derive service name from configuration
+if [ -z "$ntp_service" ]; then
+	case "$NTP_CONF" in
+	*chrony.conf)		ntp_service=chronyd;;
+	*)			ntp_service=ntpd;;
+	esac
+fi
+
+# Debian has a seperate file for DHCP config to avoid stamping on
+# the master.
+if [ "$ntp_service" = ntpd ] && type invoke-rc.d >/dev/null 2>&1; then
+	[ -e /var/lib/ntp ] || mkdir /var/lib/ntp
+	: ${ntp_service:=ntp}
+	: ${NTP_DHCP_CONF:=/var/lib/ntp/ntp.conf.dhcp}
+fi
+
+: ${ntp_restart_cmd:=service_condcommand $ntp_service restart}
+
+ntp_conf=${NTP_CONF}
+NL="
+"
+
+build_ntp_conf()
+{
+	local cf="$state_dir/ntp.conf.$ifname"
+	local interfaces= header= srvs= servers= x=
+
+	# Build a list of interfaces
+	interfaces=$(list_interfaces "$ntp_conf_dir")
+
+	if [ -n "$interfaces" ]; then
+		# Build the header
+		for x in ${interfaces}; do
+			header="$header${header:+, }$x"
+		done
+
+		# Build a server list
+		srvs=$(cd "$ntp_conf_dir";
+			key_get_value "server " $interfaces)
+		if [ -n "$srvs" ]; then
+			for x in $(uniqify $srvs); do
+				servers="${servers}server $x$NL"
+			done
+		fi
+	fi
+
+	# Merge our config into ntp.conf
+	[ -e "$cf" ] && rm -f "$cf"
+	[ -d "$ntp_conf_dir" ] || mkdir -p "$ntp_conf_dir"
+
+	if [ -n "$NTP_DHCP_CONF" ]; then
+		[ -e "$ntp_conf" ] && cp "$ntp_conf" "$cf"
+		ntp_conf="$NTP_DHCP_CONF"
+	elif [ -e "$ntp_conf" ]; then
+		remove_markers "$signature_base" "$signature_base_end" \
+			"$ntp_conf" > "$cf"
+	fi
+
+	if [ -n "$servers" ]; then
+		echo "$signature_base${header:+ $from }$header" >> "$cf"
+		printf %s "$servers" >> "$cf"
+		echo "$signature_base_end${header:+ $from }$header" >> "$cf"
+	else
+		[ -e "$ntp_conf" -a -e "$cf" ] || return
+	fi
+
+	# If we changed anything, restart ntpd
+	if change_file "$ntp_conf" "$cf"; then
+		[ -n "$ntp_restart_cmd" ] && eval $ntp_restart_cmd
+	fi
+}
+
+add_ntp_conf()
+{
+	local cf="$ntp_conf_dir/$ifname" x=
+
+	[ -e "$cf" ] && rm "$cf"
+	[ -d "$ntp_conf_dir" ] || mkdir -p "$ntp_conf_dir"
+	if [ -n "$new_ntp_servers" ]; then
+		for x in $new_ntp_servers; do
+			echo "server $x" >> "$cf"
+		done
+	fi
+	build_ntp_conf
+}
+
+remove_ntp_conf()
+{
+	if [ -e "$ntp_conf_dir/$ifname" ]; then
+		rm "$ntp_conf_dir/$ifname"
+	fi
+	build_ntp_conf
+}
+
+# For ease of use, map DHCP6 names onto our DHCP4 names
+case "$reason" in
+BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6)
+	new_ntp_servers="$new_dhcp6_sntp_servers"
+;;
+esac
+
+if $if_up; then
+	add_ntp_conf
+elif $if_down; then
+	remove_ntp_conf
+fi