Fix panic error due to file already closed in stats mode (#5774)

internal/runner/runner.go

@@ -392,6 +392,9 @@ func (r *Runner) Close() {
 	if r.tmpDir != "" {
 		_ = os.RemoveAll(r.tmpDir)
 	}
+
+	//this is no-op unless nuclei is built with stats build tag
+	events.Close()
 }
 
 // setupPDCPUpload sets up the PDCP upload writer

pkg/scan/events/scan_noop.go

@@ -9,3 +9,6 @@ func AddScanEvent(event ScanEvent) {
 
 func InitWithConfig(config *ScanConfig, statsDirectory string) {
 }
+
+func Close() {
+}

pkg/scan/events/stats_build.go

@@ -23,6 +23,7 @@ type ScanStatsWorker struct {
 	config    *ScanConfig
 	m         *sync.Mutex
 	directory string
+	file      *os.File
 	enc       *json.Encoder
 }
 
@@ -56,7 +57,7 @@ func (s *ScanStatsWorker) initEventsFile() error {
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	s.file = f
 	s.enc = json.NewEncoder(f)
 	return nil
 }
@@ -79,3 +80,22 @@ func AddScanEvent(event ScanEvent) {
 	}
 	defaultWorker.AddScanEvent(event)
 }
+
+// Close closes the file associated with the worker
+func (s *ScanStatsWorker) Close() {
+	s.m.Lock()
+	defer s.m.Unlock()
+
+	if s.file != nil {
+		_ = s.file.Close()
+		s.file = nil
+	}
+}
+
+// Close closes the file associated with the worker
+func Close() {
+	if defaultWorker == nil {
+		return
+	}
+	defaultWorker.Close()
+}