[PATCH v3 4/6] selftest/Landlock: pthread_kill(3) tests

This patch expands the signal scoping tests with pthread_kill(3)
It tests if an scoped thread can send signal to a process in
the same scoped domain, or a non-sandboxed thread.

Signed-off-by: Tahera Fahimi <[email protected]>
---
 .../selftests/landlock/scoped_signal_test.c   | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tools/testing/selftests/landlock/scoped_signal_test.c b/tools/testing/selftests/landlock/scoped_signal_test.c
index 92958c6266ca..2edba1e6cd82 100644
--- a/tools/testing/selftests/landlock/scoped_signal_test.c
+++ b/tools/testing/selftests/landlock/scoped_signal_test.c
@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/landlock.h>
+#include <pthread.h>
 #include <signal.h>
 #include <sys/prctl.h>
 #include <sys/types.h>
@@ -18,6 +19,7 @@
 
 #include "common.h"
 
+#define DEFAULT_THREAD_RUNTIME 0.001
 static sig_atomic_t signaled;
 
 static void create_signal_domain(struct __test_metadata *const _metadata)
@@ -299,4 +301,31 @@ TEST_F(signal_scoping, test_signal)
 		_metadata->exit_code = KSFT_FAIL;
 }
 
+static void *thread_func(void *arg)
+{
+	sleep(DEFAULT_THREAD_RUNTIME);
+	return NULL;
+}
+
+TEST(signal_scoping_threads)
+{
+	pthread_t no_sandbox_thread, scoped_thread;
+	int err;
+
+	ASSERT_EQ(0,
+		  pthread_create(&no_sandbox_thread, NULL, thread_func, NULL));
+	create_signal_domain(_metadata);
+	ASSERT_EQ(0, pthread_create(&scoped_thread, NULL, thread_func, NULL));
+
+	/* Send signal to threads */
+	err = pthread_kill(no_sandbox_thread, 0);
+	ASSERT_EQ(EPERM, err);
+
+	err = pthread_kill(scoped_thread, 0);
+	ASSERT_EQ(0, err);
+
+	ASSERT_EQ(0, pthread_join(scoped_thread, NULL));
+	ASSERT_EQ(0, pthread_join(no_sandbox_thread, NULL));
+}
+
 TEST_HARNESS_MAIN
-- 
2.34.1