web UI added and refactoring done

data_acq_and_processing/processing/locator/src/tcp_server.cpp

@@ -511,8 +511,16 @@ void TcpServer::acceptor_loop() {
                 std::this_thread::sleep_for(std::chrono::milliseconds(100));
                 continue;
             }
-            // Listening socket closed during shutdown produces EBADF/EINVAL; bail.
-            break;
+            // Shutdown closes the listening socket (EBADF/EINVAL) -> bail. But an
+            // unexpected errno on a still-running server (e.g. EPERM from a firewall
+            // rule) must NOT kill the acceptor and silently stop serving new clients:
+            // log, back off, and keep accepting.
+            if (!running_.load(std::memory_order_acquire)) {
+                break;
+            }
+            std::cerr << "locator: accept() failed (errno=" << errno << "); retrying\n";
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            continue;
         }
 
         reap_finished_clients();