[PATCH bpf-next v1 6/8] selftests/bpf: test autocreate behavior for struct_ops maps

[Eduard Zingerman <eddyz87@gmail.com>]

Check that bpf_map__set_autocreate() can be used to disable automatic
creation for struct_ops maps.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 .../bpf/prog_tests/struct_ops_autocreate.c    | 79 +++++++++++++++++++
 .../bpf/progs/struct_ops_autocreate.c         | 42 ++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/struct_ops_autocreate.c
 create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_autocreate.c

diff --git a/tools/testing/selftests/bpf/prog_tests/struct_ops_autocreate.c b/tools/testing/selftests/bpf/prog_tests/struct_ops_autocreate.c
new file mode 100644
index 000000000000..b21b10f94fc2
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/struct_ops_autocreate.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "struct_ops_autocreate.skel.h"
+
+#define EXPECTED_MSG "libbpf: struct_ops init_kern"
+
+static libbpf_print_fn_t old_print_cb;
+static bool msg_found;
+
+static int print_cb(enum libbpf_print_level level, const char *fmt, va_list args)
+{
+	old_print_cb(level, fmt, args);
+	if (level == LIBBPF_WARN && strncmp(fmt, EXPECTED_MSG, strlen(EXPECTED_MSG)) == 0)
+		msg_found = true;
+
+	return 0;
+}
+
+static void cant_load_full_object(void)
+{
+	struct struct_ops_autocreate *skel;
+	int err;
+
+	old_print_cb = libbpf_set_print(print_cb);
+	skel = struct_ops_autocreate__open_and_load();
+	err = errno;
+	libbpf_set_print(old_print_cb);
+	if (!ASSERT_NULL(skel, "struct_ops_autocreate__open_and_load"))
+		return;
+
+	ASSERT_EQ(err, ENOTSUP, "errno should be ENOTSUP");
+	ASSERT_TRUE(msg_found, "expected message");
+
+	struct_ops_autocreate__destroy(skel);
+}
+
+static void can_load_partial_object(void)
+{
+	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+	struct struct_ops_autocreate *skel;
+	struct bpf_link *link = NULL;
+	int err;
+
+	skel = struct_ops_autocreate__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "struct_ops_autocreate__open_opts"))
+		return;
+
+	err = bpf_program__set_autoload(skel->progs.test_2, false);
+	if (!ASSERT_OK(err, "bpf_program__set_autoload"))
+		goto cleanup;
+
+	err = bpf_map__set_autocreate(skel->maps.testmod_2, false);
+	if (!ASSERT_OK(err, "bpf_map__set_autocreate"))
+		goto cleanup;
+
+	err = struct_ops_autocreate__load(skel);
+	if (ASSERT_OK(err, "struct_ops_autocreate__load"))
+		goto cleanup;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_1);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto cleanup;
+
+	/* test_1() would be called from bpf_dummy_reg2() in bpf_testmod.c */
+	ASSERT_EQ(skel->bss->test_1_result, 42, "test_1_result");
+
+cleanup:
+	bpf_link__destroy(link);
+	struct_ops_autocreate__destroy(skel);
+}
+
+void serial_test_struct_ops_autocreate(void)
+{
+	if (test__start_subtest("cant_load_full_object"))
+		cant_load_full_object();
+	if (test__start_subtest("can_load_partial_object"))
+		can_load_partial_object();
+}
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_autocreate.c b/tools/testing/selftests/bpf/progs/struct_ops_autocreate.c
new file mode 100644
index 000000000000..294d48bb8e3c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/struct_ops_autocreate.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int test_1_result = 0;
+
+SEC("struct_ops/test_1")
+int BPF_PROG(test_1)
+{
+	test_1_result = 42;
+	return 0;
+}
+
+SEC("struct_ops/test_1")
+int BPF_PROG(test_2)
+{
+	return 0;
+}
+
+struct bpf_testmod_ops___v1 {
+	int (*test_1)(void);
+};
+
+struct bpf_testmod_ops___v2 {
+	int (*test_1)(void);
+	int (*does_not_exist)(void);
+};
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops___v1 testmod_1 = {
+	.test_1 = (void *)test_1
+};
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops___v2 testmod_2 = {
+	.test_1 = (void *)test_1,
+	.does_not_exist = (void *)test_2
+};
-- 
2.43.0