Avoid freezing SMF with a timeout

src/smf_app/smf_sbi.cpp

@@ -1322,13 +1322,18 @@ void smf_sbi::curl_release_handles() {
 
 //---------------------------------------------------------------------------------------------
 uint32_t smf_sbi::get_available_response(boost::shared_future<uint32_t>& f) {
-  f.wait();  // Wait for it to finish
+  boost::future_status status;
+  // wait for timeout or ready
+  status = f.wait_for(boost::chrono::milliseconds(FUTURE_STATUS_TIMEOUT_MS));
+  if (status == boost::future_status::ready) {
     assert(f.is_ready());
     assert(f.has_value());
     assert(!f.has_exception());
-
     uint32_t response_code = f.get();
     return response_code;
+  } else {
+    return 408;  // timeout, TODO: remove hardcoded value
+  }
 }
 
 //---------------------------------------------------------------------------------------------