Fix: read PID from pidfile instead of using shell $!

tools/utun_update.sh

@@ -65,6 +65,9 @@ if [ -f "$PIDFILE" ]; then
     rm -f "$PIDFILE"
 fi
 
+# Ensure pidfile is removed before start
+rm -f "$PIDFILE"
+
 # Git pull
 echo "Pulling latest changes..."
 if ! git pull; then
@@ -107,8 +110,22 @@ echo "Build successful: $(ls -la $UTUN_BIN)"
 # Start utun
 echo "Starting utun..."
 nohup "$UTUN_BIN" > utun_cons.log 2> utun_err.log &
-NEW_PID=$!
-sleep 2
+
+# Wait for pidfile to be created (up to 10s)
+for i in 1 2 3 4 5 6 7 8 9 10; do
+    if [ -f "$PIDFILE" ]; then
+        break
+    fi
+    sleep 1
+done
+
+# Read PID from file
+if [ -f "$PIDFILE" ]; then
+    NEW_PID=$(cat "$PIDFILE")
+else
+    echo "ERROR: Failed to start utun (pidfile not created)" >&2
+    exit 4
+fi
 
 # Verify process is running
 if kill -0 "$NEW_PID" 2>/dev/null; then