diff --git a/mkmap.sh b/mkmap.sh
index 1c6453f..28195be 100755
--- a/mkmap.sh
+++ b/mkmap.sh
@@ -3,10 +3,30 @@
 set -e
 
 DEST=$1
-
+LOCKFILE="/run/lock/ffmap"
 
 [ "$DEST" ] || exit 1
 
 cd "$(dirname "$0")"/
 
+if lockfile-check "$LOCKFILE"; then
+    exit
+fi
+lockfile-create "$LOCKFILE"
+lockfile-touch "$LOCKFILE" &
+LOCKPID="$!"
+
 ./bat2nodes.py -A -a aliases.json -d $DEST
+
+kill "$LOCKPID"
+lockfile-remove "$LOCKFILE"
+
+if lockfile-check "$LOCKFILE-sync"; then
+    exit
+fi
+lockfile-create "$LOCKFILE-sync"
+lockfile-touch "$LOCKFILE-sync" &
+LOCKPID="$!"
+
+kill "$LOCKPID"
+lockfile-remove "$LOCKFILE-sync"