1 files changed, 317 insertions, 0 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
new file mode 100644
index 000000000000..75a0dea511b3
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+#include <time.h>
+
+#include <sys/epoll.h>
+
+#include "struct_ops_module.skel.h"
+#include "struct_ops_nulled_out_cb.skel.h"
+#include "struct_ops_forgotten_cb.skel.h"
+#include "struct_ops_detach.skel.h"
+#include "unsupported_ops.skel.h"
+
+static void check_map_info(struct bpf_map_info *info)
+{
+	struct bpf_btf_info btf_info;
+	char btf_name[256];
+	u32 btf_info_len = sizeof(btf_info);
+	int err, fd;
+
+	fd = bpf_btf_get_fd_by_id(info->btf_vmlinux_id);
+	if (!ASSERT_GE(fd, 0, "get_value_type_btf_obj_fd"))
+		return;
+
+	memset(&btf_info, 0, sizeof(btf_info));
+	btf_info.name = ptr_to_u64(btf_name);
+	btf_info.name_len = sizeof(btf_name);
+	err = bpf_btf_get_info_by_fd(fd, &btf_info, &btf_info_len);
+	if (!ASSERT_OK(err, "get_value_type_btf_obj_info"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(strcmp(btf_name, "bpf_testmod"), 0, "get_value_type_btf_obj_name"))
+		goto cleanup;
+
+cleanup:
+	close(fd);
+}
+
+static int attach_ops_and_check(struct struct_ops_module *skel,
+				struct bpf_map *map,
+				int expected_test_2_result)
+{
+	struct bpf_link *link;
+
+	link = bpf_map__attach_struct_ops(map);
+	ASSERT_OK_PTR(link, "attach_test_mod_1");
+	if (!link)
+		return -1;
+
+	/* test_{1,2}() would be called from bpf_dummy_reg() in bpf_testmod.c */
+	ASSERT_EQ(skel->bss->test_1_result, 0xdeadbeef, "test_1_result");
+	ASSERT_EQ(skel->bss->test_2_result, expected_test_2_result, "test_2_result");
+
+	bpf_link__destroy(link);
+	return 0;
+}
+
+static void test_struct_ops_load(void)
+{
+	struct struct_ops_module *skel;
+	struct bpf_map_info info = {};
+	int err;
+	u32 len;
+
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+		return;
+
+	skel->struct_ops.testmod_1->data = 13;
+	skel->struct_ops.testmod_1->test_2 = skel->progs.test_3;
+	/* Since test_2() is not being used, it should be disabled from
+	 * 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"))
+		goto cleanup;
+
+	len = sizeof(info);
+	err = bpf_map_get_info_by_fd(bpf_map__fd(skel->maps.testmod_1), &info,
+				     &len);
+	if (!ASSERT_OK(err, "bpf_map_get_info_by_fd"))
+		goto cleanup;
+
+	check_map_info(&info);
+	/* test_3() will be called from bpf_dummy_reg() in bpf_testmod.c
+	 *
+	 * In bpf_testmod.c it will pass 4 and 13 (the value of data) to
+	 * .test_2.  So, the value of test_2_result should be 20 (4 + 13 +
+	 * 3).
+	 */
+	if (!attach_ops_and_check(skel, skel->maps.testmod_1, 20))
+		goto cleanup;
+	if (!attach_ops_and_check(skel, skel->maps.testmod_2, 12))
+		goto cleanup;
+
+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);
+}
+
+/* Detach a link from a user space program */
+static void test_detach_link(void)
+{
+	struct epoll_event ev, events[2];
+	struct struct_ops_detach *skel;
+	struct bpf_link *link = NULL;
+	int fd, epollfd = -1, nfds;
+	int err;
+
+	skel = struct_ops_detach__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_detach__open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
+	if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
+		goto cleanup;
+
+	fd = bpf_link__fd(link);
+	if (!ASSERT_GE(fd, 0, "link_fd"))
+		goto cleanup;
+
+	epollfd = epoll_create1(0);
+	if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
+		goto cleanup;
+
+	ev.events = EPOLLHUP;
+	ev.data.fd = fd;
+	err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
+	if (!ASSERT_OK(err, "epoll_ctl"))
+		goto cleanup;
+
+	err = bpf_link__detach(link);
+	if (!ASSERT_OK(err, "detach_link"))
+		goto cleanup;
+
+	/* Wait for EPOLLHUP */
+	nfds = epoll_wait(epollfd, events, 2, 500);
+	if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
+		goto cleanup;
+	if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
+		goto cleanup;
+
+cleanup:
+	if (epollfd >= 0)
+		close(epollfd);
+	bpf_link__destroy(link);
+	struct_ops_detach__destroy(skel);
+}
+
+void serial_test_struct_ops_module(void)
+{
+	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();
+	if (test__start_subtest("test_detach_link"))
+		test_detach_link();
+	RUN_TESTS(unsupported_ops);
+}
+