diff --git a/lib/c/criu.c b/lib/c/criu.c
index a7df66a7a..76385e038 100644
--- a/lib/c/criu.c
+++ b/lib/c/criu.c
@@ -840,6 +840,35 @@ int criu_add_inherit_fd(int fd, char *key)
 	return criu_local_add_inherit_fd(global_opts, fd, key);
 }
 
+int criu_local_add_external(criu_opts *opts, char *key)
+{
+	int nr;
+	char **a, *e = NULL;
+
+	e = strdup(key);
+	if (!e)
+		goto err;
+
+	nr = opts->rpc->n_external + 1;
+	a = realloc(opts->rpc->external, nr * sizeof(*a));
+	if (!a)
+		goto err;
+
+	a[nr - 1] = e;
+	opts->rpc->external = a;
+	opts->rpc->n_external = nr;
+	return 0;
+err:
+	if (e)
+		free(e);
+	return -ENOMEM;
+}
+
+int criu_add_external(char *key)
+{
+	return criu_local_add_external(global_opts, key);
+}
+
 static CriuResp *recv_resp(int socket_fd)
 {
 	unsigned char *buf = NULL;
diff --git a/lib/c/criu.h b/lib/c/criu.h
index 5785044d1..f887b711f 100644
--- a/lib/c/criu.h
+++ b/lib/c/criu.h
@@ -93,6 +93,7 @@ int criu_add_skip_mnt(char *mnt);
 void criu_set_ghost_limit(unsigned int limit);
 int criu_add_irmap_path(char *path);
 int criu_add_inherit_fd(int fd, char *key);
+int criu_add_external(char *key);
 
 /*
  * The criu_notify_arg_t na argument is an opaque
@@ -202,6 +203,7 @@ int criu_local_add_cg_props(criu_opts *opts, char *stream);
 int criu_local_add_cg_props_file(criu_opts *opts, char *path);
 int criu_local_add_cg_dump_controller(criu_opts *opts, char *name);
 int criu_local_add_inherit_fd(criu_opts *opts, int fd, char *key);
+int criu_local_add_external(criu_opts *opts, char *key);
 
 void criu_local_set_notify_cb(criu_opts *opts, int (*cb)(char *action, criu_notify_arg_t na));