ua.c Do not core dump when no calls are active

Using "l" in menu.so caused a core dump.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/ua.c b/src/ua.c
index c4908c4..5aeb3bf 100644
--- a/src/ua.c
+++ b/src/ua.c
@@ -1325,6 +1325,10 @@ int ua_print_calls(struct re_printf *pf, const struct ua *ua)
 {
 	struct le *le;
 	int err = 0;
+	if (!ua) {
+		err |= re_hprintf(pf, "\n--- No active calls ---\n");
+		return err;
+	}
 
 	err |= re_hprintf(pf, "\n--- List of active calls (%u): ---\n",
 			  list_count(&ua->calls));