acl: Avoid passing NULL parameter to printf %s when mail_debug=yes

diff --git a/src/plugins/acl/acl-backend-vfile.c b/src/plugins/acl/acl-backend-vfile.c
index cb7a4609c32d7b41755a904dcdf05a90fe44f99e..98800c89b7790cb0711e809cb57393b5d371192a 100644 (file)
--- a/src/plugins/acl/acl-backend-vfile.c
+++ b/src/plugins/acl/acl-backend-vfile.c
@@ -102,6 +102,7 @@ acl_backend_vfile_init(struct acl_backend *_backend, const char *data)
        }
        if (_backend->debug) {
                i_debug("acl vfile: Global ACL directory: %s",
+                       backend->global_dir == NULL ? "(none)" :
                        backend->global_dir);
        }