Imitate how free(3) behaves and make map_clear() works on NULL map.

diff --git a/usr.sbin/btrace/map.c b/usr.sbin/btrace/map.c
index b5bb8fb..5624db6 100644 (file)
--- a/usr.sbin/btrace/map.c
+++ b/usr.sbin/btrace/map.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: map.c,v 1.15 2021/09/01 07:35:21 mpi Exp $ */
+/*     $OpenBSD: map.c,v 1.16 2021/09/01 08:06:49 mpi Exp $ */
 
 /*
  * Copyright (c) 2020 Martin Pieuchot <mpi@openbsd.org>
@@ -84,6 +84,9 @@ map_clear(struct map *map)
 {
        struct mentry *mep;
 
+       if (map == NULL)
+               return;
+
        while ((mep = RB_MIN(map, map)) != NULL) {
                RB_REMOVE(map, map, mep);
                free(mep);