1 files changed, 5 insertions, 0 deletions
diff --git a/src/or/control.c b/src/or/control.c
index a2ae2e9f1d..e2ad8cc6dc 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -2011,6 +2011,11 @@ getinfo_helper_dir(control_connection_t *control_conn,
       char *filename = get_datadir_fname("cached-consensus");
       *answer = read_file_to_str(filename, RFTS_IGNORE_MISSING, NULL);
       tor_free(filename);
+      if (!*answer) { /* generate an error */
+        *errmsg = "Could not open cached consensus. "
+          "Make sure FetchUselessDescriptors is set to 1.";
+        return -1;
+      }
     }
   } else if (!strcmp(question, "network-status")) { /* v1 */
     routerlist_t *routerlist = router_get_routerlist();