2 files changed, 51 insertions, 0 deletions
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index aecf6b8..9b5c4bf 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -21,6 +21,7 @@ target_link_libraries(${TORTURE_LIBRARY}
 set(SWRAP_TESTS
     test_ioctl
     test_tcp_listen
+    test_tcp_dup2
     test_echo_tcp_socket
     test_echo_tcp_connect
     test_echo_tcp_bind
diff --git a/tests/test_tcp_dup2.c b/tests/test_tcp_dup2.c
new file mode 100644
index 0000000..fd6adc2
--- /dev/null
+++ b/tests/test_tcp_dup2.c
@@ -0,0 +1,50 @@
+#include "torture.h"
+
+#include <cmocka.h>
+#include <unistd.h>
+
+static int setup(void **state)
+{
+	torture_setup_socket_dir(state);
+
+	return 0;
+}
+
+static int teardown(void **state)
+{
+	torture_teardown_socket_dir(state);
+
+	return 0;
+}
+
+static void test_dup2_existing_open_fd(void **state)
+{
+	int s, dup_s;
+
+	(void) state; /* unused */
+
+	s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	assert_int_not_equal(s, -1);
+
+	/*
+	 * Here we try to duplicate the existing socket fd to itself
+	 * and as per man page for dup2() it must return the already
+	 * open fd without any failure.
+	 */
+	dup_s = dup2(s, s);
+	assert_int_equal(dup_s, s);
+
+	close(s);
+}
+
+int main(void) {
+	int rc;
+
+	const struct CMUnitTest tcp_dup2_tests[] = {
+		cmocka_unit_test(test_dup2_existing_open_fd),
+	};
+
+	rc = cmocka_run_group_tests(tcp_dup2_tests, setup, teardown);
+
+	return rc;
+}