fix(portforward): rework run loop and fix deadlocks (#1874)

internal/portforward/service/start.go

@@ -0,0 +1,60 @@
+package service
+
+import (
+	"context"
+	"fmt"
+)
+
+func (s *Service) Start(ctx context.Context) (runError <-chan error, err error) {
+	s.startStopMutex.Lock()
+	defer s.startStopMutex.Unlock()
+
+	if !*s.settings.UserSettings.Enabled {
+		return nil, nil //nolint:nilnil
+	}
+
+	s.logger.Info("starting")
+	port, err := s.settings.PortForwarder.PortForward(ctx, s.client, s.logger,
+		s.settings.Gateway, s.settings.ServerName)
+	if err != nil {
+		return nil, fmt.Errorf("port forwarding for the first time: %w", err)
+	}
+
+	s.logger.Info("port forwarded is " + fmt.Sprint(int(port)))
+
+	err = s.portAllower.SetAllowedPort(ctx, port, s.settings.Interface)
+	if err != nil {
+		return nil, fmt.Errorf("allowing port in firewall: %w", err)
+	}
+
+	err = s.writePortForwardedFile(port)
+	if err != nil {
+		_ = s.cleanup()
+		return nil, fmt.Errorf("writing port file: %w", err)
+	}
+
+	s.portMutex.Lock()
+	s.port = port
+	s.portMutex.Unlock()
+
+	keepPortCtx, keepPortCancel := context.WithCancel(context.Background())
+	s.keepPortCancel = keepPortCancel
+	runErrorCh := make(chan error)
+	keepPortDoneCh := make(chan struct{})
+	s.keepPortDoneCh = keepPortDoneCh
+
+	go func(ctx context.Context, settings Settings, port uint16,
+		runError chan<- error, doneCh chan<- struct{}) {
+		defer close(doneCh)
+		err = settings.PortForwarder.KeepPortForward(ctx, port,
+			settings.Gateway, settings.ServerName, s.logger)
+		crashed := ctx.Err() == nil
+		if !crashed { // stopped by Stop call
+			return
+		}
+		_ = s.cleanup()
+		runError <- err
+	}(keepPortCtx, s.settings, port, runErrorCh, keepPortDoneCh)
+
+	return runErrorCh, nil
+}