tests: Test libexecinfo backtrace call througth signal trampoline

It should fails on Aarch64 until https://reviews.llvm.org/D155066
is not merged.

Reviewed by:
Differential Revision:	https://reviews.freebsd.org/D41129

lib/libexecinfo/tests/Makefile

@@ -14,7 +14,10 @@ STRIP=
 # so that doesn't seem useful.
 NETBSD_ATF_TESTS_C+=	backtrace_test
 
+ATF_TESTS_C+=		sigtramp_test
+
 LIBADD.backtrace_test+=	execinfo
+LIBADD.sigtramp_test+=	execinfo
 
 .include <netbsd-tests.test.mk>
 

lib/libexecinfo/tests/sigtramp_test.c

@@ -0,0 +1,75 @@
+/*-
+ * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/wait.h>
+
+#include <execinfo.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <atf-c.h>
+
+#define	BT_FUNCTIONS		10
+
+void	handler(int);
+
+__noinline void
+handler(int signum __unused)
+{
+	void *addresses[BT_FUNCTIONS];
+	char **symbols;
+	size_t n, i, match;
+
+	n = backtrace(addresses, nitems(addresses));
+	ATF_REQUIRE(n > 1);
+	symbols = backtrace_symbols(addresses, n);
+	ATF_REQUIRE(symbols != NULL);
+
+	match = -1;
+	for (i = 0; i < n; i++) {
+		printf("%zu: %p, %s\n", i, addresses[i], symbols[i]);
+		if (strstr(symbols[i], "<main+") != NULL)
+			match = i;
+	}
+	ATF_REQUIRE(match > 0);
+	printf("match at %zu, symbols %zu\n", match, n);
+
+}
+
+ATF_TC_WITHOUT_HEAD(test_backtrace_sigtramp);
+ATF_TC_BODY(test_backtrace_sigtramp, tc)
+{
+	struct sigaction act;
+	pid_t child;
+	int status;
+
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = handler;
+	sigemptyset(&act.sa_mask);
+	sigaction(SIGUSR1, &act, NULL);
+
+	child = fork();
+	ATF_REQUIRE(child != -1);
+
+	if (child == 0) {
+		kill(getppid(), SIGUSR1);
+		_exit(0);
+	} else
+		wait(&status);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, test_backtrace_sigtramp);
+
+	return (atf_no_error());
+}