+ $USTD --pidfile "$pidfilepath" -s "$USTDSOCKPATH" -o "$OUTDIR" >"$OUTDIR/ustd.log" 2>&1 &
+ # ustd sets up its server socket
+ # ustd opens the pidfile, blocks because no one has opened it
+ # we open pidfile
+ # we block reading pidfile
+ # ustd writes to pidfile
+ # ustd closes pidfile
+ # we unblock reading pidfile