Basic signal tests: Can we deliver a signal?

Basic signal tests that tests can we deliver a signal via raise() and
can we deliver one via SIGALARM asynchronously.

In addition, tests whether or not on ARM T32 (Thumb) code can interrupt
A32 (normal) and vice versa.

While this test is aimed at ensuring basic qemu signals are working,
it's good to have in the base.

Sponsored by:		Netflix
Discussed with:		kevans, cognet
Differential Revision:	https://reviews.freebsd.org/D33078

tests/sys/kern/Makefile

@@ -9,6 +9,7 @@ TESTSRC=	${SRCTOP}/contrib/netbsd-tests/kernel
 
 TESTSDIR=	${TESTSBASE}/sys/kern
 
+ATF_TESTS_C+=	basic_signal
 #ATF_TESTS_C+=	kcov
 ATF_TESTS_C+=	kern_copyin
 ATF_TESTS_C+=	kern_descrip_test

tests/sys/kern/basic_signal.c

@@ -0,0 +1,159 @@
+/*-
+ * Copyright (c) 2021 Warner Losh <imp@bsdimp.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <atf-c.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+static volatile sig_atomic_t signal_fired = 0;
+
+static void
+sig_handler(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	signal_fired++;
+}
+
+ATF_TC(signal_test);
+
+ATF_TC_HEAD(signal_test, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal");
+}
+
+ATF_TC_BODY(signal_test, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_handler,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR2, &sa, NULL) == 0);
+	ATF_REQUIRE(sigaction(SIGALRM, &sa, NULL) == 0);
+
+	/*
+	 * Fire SIGUSR1
+	 */
+	ATF_CHECK(signal_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(signal_fired == 1);
+
+	/*
+	 * Fire SIGUSR2
+	 */
+	ATF_REQUIRE(raise(SIGUSR2) == 0);
+	ATF_CHECK(signal_fired == 2);
+
+	/*
+	 * Fire SIGALRM after a timeout
+	 */
+	ATF_REQUIRE(alarm(1) == 0);
+	ATF_REQUIRE(pause() == -1);
+	ATF_REQUIRE(errno == EINTR);
+	ATF_CHECK(signal_fired == 3);
+}
+
+/*
+ * Special tests for 32-bit arm. We can call thumb code (really just t32) from
+ * normal (a32) mode and vice versa. Likewise, signals can interrupt a T32
+ * context with A32 code and vice versa. Make sure these all work with a simple
+ * test that raises the signal and ensures that it executed. No other platform
+ * has these requirements. Also note: we only support thumb2, so there's no T16
+ * vs T32 issues we have to test for.
+ */
+#ifdef __arm__
+
+#define a32_isa __attribute__((target("arm")))
+#define t32_isa __attribute__((target("thumb")))
+
+static volatile sig_atomic_t t32_fired = 0;
+static volatile sig_atomic_t a32_fired = 0;
+
+a32_isa static void
+sig_a32(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	a32_fired++;
+}
+
+t32_isa static void
+sig_t32(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	t32_fired++;
+}
+
+
+ATF_TC(signal_test_T32_to_A32);
+
+ATF_TC_HEAD(signal_test_T32_to_A32, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal from T32 to A32");
+}
+
+t32_isa ATF_TC_BODY(signal_test_T32_to_A32, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_a32,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+
+	ATF_REQUIRE((((uintptr_t)sig_a32) & 1) == 0); /* Make sure compiled as not thumb */
+
+	ATF_CHECK(a32_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(a32_fired == 1);
+}
+
+ATF_TC(signal_test_A32_to_T32);
+
+ATF_TC_HEAD(signal_test_A32_to_T32, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal from A32 to T32");
+}
+
+a32_isa ATF_TC_BODY(signal_test_A32_to_T32, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_t32,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+
+	ATF_REQUIRE((((uintptr_t)sig_t32) & 1) == 1);	/* Make sure compiled as thumb */
+
+	ATF_CHECK(t32_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(t32_fired == 1);
+}
+#endif
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, signal_test);
+#ifdef __arm__
+	ATF_TP_ADD_TC(tp, signal_test_T32_to_A32);
+	ATF_TP_ADD_TC(tp, signal_test_A32_to_T32);
+#endif
+
+	return (atf_no_error());
+}