birdc: Do not execute cmd on noninteractive help request

The help command triggered by '?' keeps the message in readline buffer,
so it could be edited. For noninteractive shell it leads to an unexpected
side effect that `echo <cmd> ? | birdc` executes the command <cmd> after
showing its help. Avoid this by clearing the readline buffer in such case.

diff --git a/client/birdc.c b/client/birdc.c
index f1aea2fee60f819b3a0c45e01708ef776aa650aa..3e4a64f4c51ac7dbb0ee8eb6c3edd74cdfb4f94d 100644 (file)
--- a/client/birdc.c
+++ b/client/birdc.c
@@ -136,6 +136,9 @@ input_help(int arg, int key UNUSED)
   input_start_list();
   cmd_help(rl_line_buffer, rl_point);
   rl_undo_command(1, 0);
+  /* <cmd> ? is "internal". Do not submit command in non interactive session */
+  if (!interactive)
+    rl_replace_line("", 0);
   input_stop_list();
   return 0;
 }