[Lldb-commits] [lldb] [lldb] Removed gdbserver ports map from lldb-server (PR #104238)

[Pavel Labath via lldb-commits]

================
@@ -601,15 +570,24 @@ int main_platform(int argc, char *argv[]) {
       // If not running as a server, this process will not accept
       // connections while a connection is active.
       acceptor_up.reset();
-
-      // When not running in server mode, use all available ports
-      platform.SetPortMap(std::move(gdbserver_portmap));
     }
 
     platform.SetConnection(std::unique_ptr<Connection>(conn));
     client_handle(platform, inferior_arguments);
   } while (g_server);
 
+  // FIXME: Make TCPSocket::CloseListenSockets() public and implement
+  // Acceptor::Close().
+  /*
+  if (acceptor_gdb && gdb_thread.IsJoinable()) {
+    g_listen_gdb = false;
+    static_cast<TCPSocket *>(acceptor_gdb->m_listener_socket_up.get())
+        ->CloseListenSockets();
+    lldb::thread_result_t result;
+    gdb_thread.Join(&result);
+  }
+  */
+
----------------
labath wrote:

This won't work. This is exactly the pattern from that kernel bug we were arguing over. It's just not possible to safely close an fd while another thread may be operating on it.

You need to use an out-of-band mechanism (e.g. a pipe) to notify the thread that it's time to terminate. However, since that will involve some form of multiplexing (e.g. `select(2)`). I would strongly prefer to just multiplex over the two sockets we are accepting. We should be able to use the `MainLoop` class for that -- just register the two sockets with the class, and let it call the right callback when needed. Basically, the code should look similar to [this](https://github.com/llvm/llvm-project/blob/f71b63865140cf3c286baf3a77ba3e467f929504/lldb/source/Host/common/TCPSocket.cpp#L267), except that it will be listening to two unrelated sockets.

https://github.com/llvm/llvm-project/pull/104238