swrap: introduce a socket_wrapper_noop.so and socket_wrapper.h to provide noop stubs

Applications with the need to call socket_wrapper_enabled() should link
against -lsocket_wrapper_noop in order to resolve the symbol at
link time.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14640

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>

2 files changed, 80 insertions, 1 deletions

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index db36bf3..2f98af1 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -56,6 +56,7 @@ set(SWRAP_TESTS
     test_echo_udp_sendmsg_recvmsg
     test_swrap_unit
     test_max_sockets
+    test_public_functions
     test_close_failure
     test_tcp_socket_overwrite
     ${SWRAP_THREADED_TESTS})
@@ -111,7 +112,7 @@ foreach(_SWRAP_TEST ${SWRAP_TESTS})
     add_cmocka_test(${_SWRAP_TEST}
                     SOURCES ${_SWRAP_TEST}.c
                     COMPILE_OPTIONS ${DEFAULT_C_COMPILE_FLAGS} -D_GNU_SOURCE
-                    LINK_LIBRARIES ${TORTURE_LIBRARY}
+                    LINK_LIBRARIES ${TORTURE_LIBRARY} socket_wrapper_noop
                     LINK_OPTIONS ${DEFAULT_LINK_FLAGS})
     add_cmocka_test_environment(${_SWRAP_TEST})
 endforeach()
diff --git a/tests/test_public_functions.c b/tests/test_public_functions.c
new file mode 100644
index 0000000..11d03ef
--- /dev/null
+++ b/tests/test_public_functions.c
@@ -0,0 +1,78 @@
+#include "torture.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <cmocka.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include <socket_wrapper.h>
+
+static int setup_enabled(void **state)
+{
+	torture_setup_socket_dir(state);
+
+	return 0;
+}
+
+static int teardown_enabled(void **state)
+{
+	torture_teardown_socket_dir(state);
+
+	return 0;
+}
+
+static int setup_disabled(void **state)
+{
+	(void) state; /* unused */
+
+	unsetenv("SOCKET_WRAPPER_DIR");
+	unsetenv("SOCKET_WRAPPER_DEFAULT_IFACE");
+	unsetenv("SOCKET_WRAPPER_PCAP_FILE");
+
+	return 0;
+}
+
+static int teardown_disabled(void **state)
+{
+	(void) state; /* unused */
+
+	return 0;
+}
+
+static void test_call_enabled_true(void **state)
+{
+	char *s = getenv("SOCKET_WRAPPER_DIR");
+
+	(void) state; /* unused */
+
+	assert_true(socket_wrapper_enabled());
+	assert_true(s != NULL);
+}
+
+static void test_call_enabled_false(void **state)
+{
+	char *s = getenv("SOCKET_WRAPPER_DIR");
+
+	(void) state; /* unused */
+
+	assert_false(socket_wrapper_enabled());
+	assert_false(s != NULL);
+}
+
+int main(void) {
+	int rc;
+
+	const struct CMUnitTest max_sockets_tests[] = {
+		cmocka_unit_test_setup_teardown(test_call_enabled_true,
+						setup_enabled,
+						teardown_enabled),
+		cmocka_unit_test_setup_teardown(test_call_enabled_false,
+						setup_disabled,
+						teardown_disabled),
+	};
+
+	rc = cmocka_run_group_tests(max_sockets_tests, NULL, NULL);
+
+	return rc;
+}