Check return code when downloading files

main.c

@@ -401,6 +401,11 @@ void parse_config (void) {
     tasprintf (&secret_chat_file_name, "%s/%s/%s", get_home_directory (), CONFIG_DIRECTORY, SECRET_CHAT_FILE);
   }
   tgl_set_download_directory (downloads_directory);
+  if (!mkdir (downloads_directory, CONFIG_DIRECTORY_MODE)) {
+    if (!disable_output) {
+      printf ("[%s] created\n", downloads_directory);
+    }
+  }
 }
 #endif
 

queries.c

@@ -2415,6 +2415,10 @@ static int download_on_answer (struct query *q) {
   struct download *D = q->extra;
   if (D->fd == -1) {
     D->fd = open (D->name, O_CREAT | O_WRONLY, 0640);
+    if (D->fd < 0) {
+      vlogprintf (E_ERROR, "Can not open for writing: %m\n");
+      assert (D->fd >= 0);
+    }
   }
   fetch_int (); // mtime
   int len = prefetch_strlen ();