actions: properly release resources once the external command exits

sftpd/sftpd.go

@@ -321,8 +321,11 @@ func executeAction(operation string, username string, path string, target string
 		if _, err = os.Stat(actions.Command); err == nil {
 			command := exec.Command(actions.Command, operation, username, path, target)
 			err = command.Start()
-			logger.Debug(logSender, "executed command \"%v\" with arguments: %v, %v, %v, %v, error: %v",
+			logger.Debug(logSender, "start command \"%v\" with arguments: %v, %v, %v, %v, error: %v",
 				actions.Command, operation, username, path, target, err)
+			if err == nil {
+				go command.Wait()
+			}
 		} else {
 			logger.Warn(logSender, "Invalid action command \"%v\" : %v", actions.Command, err)
 		}