1 files changed, 158 insertions, 1 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
index ee5372c7f2c7..29e183a80f49 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -4,6 +4,8 @@
 #include <time.h>
 
 #include "struct_ops_module.skel.h"
+#include "struct_ops_nulled_out_cb.skel.h"
+#include "struct_ops_forgotten_cb.skel.h"
 
 static void check_map_info(struct bpf_map_info *info)
 {
@@ -66,6 +68,7 @@ static void test_struct_ops_load(void)
 	 * auto-loading, or it will fail to load.
 	 */
 	bpf_program__set_autoload(skel->progs.test_2, false);
+	bpf_map__set_autocreate(skel->maps.testmod_zeroed, false);
 
 	err = struct_ops_module__load(skel);
 	if (!ASSERT_OK(err, "struct_ops_module_load"))
@@ -93,9 +96,163 @@ cleanup:
 	struct_ops_module__destroy(skel);
 }
 
+static void test_struct_ops_not_zeroed(void)
+{
+	struct struct_ops_module *skel;
+	int err;
+
+	/* zeroed is 0, and zeroed_op is null */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+		return;
+
+	skel->struct_ops.testmod_zeroed->zeroed = 0;
+	/* zeroed_op prog should be not loaded automatically now */
+	skel->struct_ops.testmod_zeroed->zeroed_op = NULL;
+
+	err = struct_ops_module__load(skel);
+	ASSERT_OK(err, "struct_ops_module_load");
+
+	struct_ops_module__destroy(skel);
+
+	/* zeroed is not 0 */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed"))
+		return;
+
+	/* libbpf should reject the testmod_zeroed since struct
+	 * bpf_testmod_ops in the kernel has no "zeroed" field and the
+	 * value of "zeroed" is non-zero.
+	 */
+	skel->struct_ops.testmod_zeroed->zeroed = 0xdeadbeef;
+	skel->struct_ops.testmod_zeroed->zeroed_op = NULL;
+	err = struct_ops_module__load(skel);
+	ASSERT_ERR(err, "struct_ops_module_load_not_zeroed");
+
+	struct_ops_module__destroy(skel);
+
+	/* zeroed_op is not null */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed_op"))
+		return;
+
+	/* libbpf should reject the testmod_zeroed since the value of its
+	 * "zeroed_op" is not null.
+	 */
+	skel->struct_ops.testmod_zeroed->zeroed_op = skel->progs.test_3;
+	err = struct_ops_module__load(skel);
+	ASSERT_ERR(err, "struct_ops_module_load_not_zeroed_op");
+
+	struct_ops_module__destroy(skel);
+}
+
+/* The signature of an implementation might not match the signature of the
+ * function pointer prototype defined in the BPF program. This mismatch
+ * should be allowed as long as the behavior of the operator program
+ * adheres to the signature in the kernel. Libbpf should not enforce the
+ * signature; rather, let the kernel verifier handle the enforcement.
+ */
+static void test_struct_ops_incompatible(void)
+{
+	struct struct_ops_module *skel;
+	struct bpf_link *link;
+	int err;
+
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+		return;
+
+	bpf_map__set_autocreate(skel->maps.testmod_zeroed, false);
+
+	err = struct_ops_module__load(skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto cleanup;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_incompatible);
+	if (ASSERT_OK_PTR(link, "attach_struct_ops"))
+		bpf_link__destroy(link);
+
+cleanup:
+	struct_ops_module__destroy(skel);
+}
+
+/* validate that it's ok to "turn off" callback that kernel supports */
+static void test_struct_ops_nulled_out_cb(void)
+{
+	struct struct_ops_nulled_out_cb *skel;
+	int err;
+
+	skel = struct_ops_nulled_out_cb__open();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	/* kernel knows about test_1, but we still null it out */
+	skel->struct_ops.ops->test_1 = NULL;
+
+	err = struct_ops_nulled_out_cb__load(skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto cleanup;
+
+	ASSERT_FALSE(bpf_program__autoload(skel->progs.test_1_turn_off), "prog_autoload");
+	ASSERT_LT(bpf_program__fd(skel->progs.test_1_turn_off), 0, "prog_fd");
+
+cleanup:
+	struct_ops_nulled_out_cb__destroy(skel);
+}
+
+/* validate that libbpf generates reasonable error message if struct_ops is
+ * not referenced in any struct_ops map
+ */
+static void test_struct_ops_forgotten_cb(void)
+{
+	struct struct_ops_forgotten_cb *skel;
+	char *log;
+	int err;
+
+	skel = struct_ops_forgotten_cb__open();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	start_libbpf_log_capture();
+
+	err = struct_ops_forgotten_cb__load(skel);
+	if (!ASSERT_ERR(err, "skel_load"))
+		goto cleanup;
+
+	log = stop_libbpf_log_capture();
+	ASSERT_HAS_SUBSTR(log,
+			  "prog 'test_1_forgotten': SEC(\"struct_ops\") program isn't referenced anywhere, did you forget to use it?",
+			  "libbpf_log");
+	free(log);
+
+	struct_ops_forgotten_cb__destroy(skel);
+
+	/* now let's programmatically use it, we should be fine now */
+	skel = struct_ops_forgotten_cb__open();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	skel->struct_ops.ops->test_1 = skel->progs.test_1_forgotten; /* not anymore */
+
+	err = struct_ops_forgotten_cb__load(skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto cleanup;
+
+cleanup:
+	struct_ops_forgotten_cb__destroy(skel);
+}
+
 void serial_test_struct_ops_module(void)
 {
-	if (test__start_subtest("test_struct_ops_load"))
+	if (test__start_subtest("struct_ops_load"))
 		test_struct_ops_load();
+	if (test__start_subtest("struct_ops_not_zeroed"))
+		test_struct_ops_not_zeroed();
+	if (test__start_subtest("struct_ops_incompatible"))
+		test_struct_ops_incompatible();
+	if (test__start_subtest("struct_ops_null_out_cb"))
+		test_struct_ops_nulled_out_cb();
+	if (test__start_subtest("struct_ops_forgotten_cb"))
+		test_struct_ops_forgotten_cb();
 }