deferable-reboot move cron command to file

packages/deferable-reboot/files/etc/uci-defaults/90-cron-defer-reboot

@@ -6,6 +6,5 @@ unique_append()
 }
 
 unique_append \
-	"*/3 * * * * ((sleep $((RANDOM % 120)); if ping -c 10 -W 10 \$(uci -q get lime-autogen.system.deferable_reboot_ping_target) &> /dev/null; then awk '{print \$1 + 1800}' /proc/uptime > /tmp/deferable-reboot.defer ; fi )&) "\
-	/etc/crontabs/root
+	"*/3 * * * * ((sleep $((RANDOM % 120)); /usr/bin/deferable-reboot-check )&)" /etc/crontabs/root
 

packages/deferable-reboot/files/usr/bin/deferable-reboot-check

@@ -0,0 +1,17 @@
+#!/bin/sh
+
+uci_config_path="lime-autogen.system.deferable_reboot_ping_target"
+target=$(uci -q get $uci_config_path &> /dev/null)
+
+if [ -n "$target" ]; then
+    if ping -c 10 -W 10 $target; then
+        action=defer
+    fi
+else
+    echo "deferable-reboot: Could not get the ping target from UCI $uci_config_path, deferring anyway"
+    action=defer
+fi
+
+if [ "$action" == "defer" ]; then
+    awk '{print $1 + 1800}' /proc/uptime > /tmp/deferable-reboot.defer
+fi