only sync root fs when a new one is available

imagesync.sh

@@ -115,9 +115,33 @@ aria2c --allow-overwrite --check-integrity --seed-time=0 --summary-interval=0 --
 rm dht.dat
 print_done
 
-print_waiting "Extracting root filesystem image"
-tar xzf rootfs.tar.gz
-print_done
+print_waiting "Comparing installed and remote image"
+if [ -f /tmp_root/.build_uuid ];then
+	cd /tmp
+	tar xzf /tmp_root/rootfs.tar.gz .build_uuid
+	if [ $(cat .build_uuid) == $(cat /tmp_root/.build_uuid) ];then
+		sync=false
+	else
+		sync=true
+		print_done
+		print_waiting "Deleting old filesystem"
+		cd /tmp_root
+		rm -rf $(tar tzf rootfs.tar.gz|grep '^[^/]*/$' )
+		cd /tmp
+		print_done
+	fi
+	rm .build_uuid
+	cd /tmp_root
+else
+	sync=true
+	print_done
+fi
+
+if [ $sync == "true" ];then
+	print_waiting "Extracting root filesystem image"
+	tar xzf rootfs.tar.gz
+	print_done
+fi
 
 ##
 # UNMOUNT TEMPORARY ROOTFS