2 files changed, 78 insertions, 0 deletions
diff --git a/lib/libc/tests/stdlib/libatexit/Makefile b/lib/libc/tests/stdlib/libatexit/Makefile
new file mode 100644
index 000000000000..9ba04c77af62
--- /dev/null
+++ b/lib/libc/tests/stdlib/libatexit/Makefile
@@ -0,0 +1,11 @@
+SHLIB_CXX=		libatexit
+SHLIB_NAME=		libatexit.so
+SHLIB_MAJOR=		1
+SHLIBDIR=	${TESTSDIR}
+PACKAGE=	tests
+SRCS=		libatexit.cc
+
+TESTSDIR:=	${TESTSBASE}/${RELDIR:C/libc\/tests/libc/:H}
+
+
+.include <bsd.lib.mk>
diff --git a/lib/libc/tests/stdlib/libatexit/libatexit.cc b/lib/libc/tests/stdlib/libatexit/libatexit.cc
new file mode 100644
index 000000000000..bb286c97e421
--- /dev/null
+++ b/lib/libc/tests/stdlib/libatexit/libatexit.cc
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2025 Kyle Evans <kevans@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ */
+
+#include <unistd.h>
+
+static int exit_code = -1;
+static bool fatal_atexit;
+
+extern "C" {
+	void set_fatal_atexit(bool);
+	void set_exit_code(int);
+}
+
+void
+set_fatal_atexit(bool fexit)
+{
+	fatal_atexit = fexit;
+}
+
+void
+set_exit_code(int code)
+{
+	exit_code = code;
+}
+
+struct other_object {
+	~other_object() {
+
+		/*
+		 * In previous versions of our __cxa_atexit handling, we would
+		 * never actually execute this handler because it's added during
+		 * ~object() below; __cxa_finalize would never revisit it.  We
+		 * will allow the caller to configure us to exit with a certain
+		 * exit code so that it can run us twice: once to ensure we
+		 * don't crash at the end, and again to make sure the handler
+		 * actually ran.
+		 */
+		if (exit_code != -1)
+			_exit(exit_code);
+	}
+};
+
+void
+create_staticobj()
+{
+	static other_object obj;
+}
+
+struct object {
+	~object() {
+		/*
+		 * If we're doing the fatal_atexit behavior (i.e., create an
+		 * object that will add its own dtor for __cxa_finalize), then
+		 * we don't exit here.
+		 */
+		if (fatal_atexit)
+			create_staticobj();
+		else if (exit_code != -1)
+			_exit(exit_code);
+	}
+};
+
+static object obj;