[PATCH bpf-next 7/9] selftests/bpf: Verify tracing_multi link_create logs

[Leon Hwang <leon.hwang@linux.dev>]

Check the error code, log message, and reported log size for a zero or
excessive count, missing IDs, invalid flags, and a nonzero target FD.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
 .../selftests/bpf/prog_tests/tracing_link.c   | 102 ++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_link.c b/tools/testing/selftests/bpf/prog_tests/tracing_link.c
index 1b64cb3e9983..6f22a21be946 100644
--- a/tools/testing/selftests/bpf/prog_tests/tracing_link.c
+++ b/tools/testing/selftests/bpf/prog_tests/tracing_link.c
@@ -5,6 +5,7 @@
 #include "priv_freplace_prog.skel.h"
 #include "xdp_dummy.skel.h"
 #include "kprobe_write_ctx.skel.h"
+#include "tracing_multi_fail.skel.h"
 
 static void test_fentry_link_create_log(int target_fd, __u32 target_btf_id, int cookie,
 					enum bpf_attach_type attach_type,
@@ -273,3 +274,104 @@ void test_tracing_link_log(void)
 	if (test__start_subtest("invalid_kprobe_write_ctx"))
 		test_log_invalid_kprobe_write_ctx();
 }
+
+static void test_tracing_multi_link_create_log(int target_fd, __u32 flags, const __u32 *ids,
+					       __u32 cnt, int err_exp, const char *msg)
+{
+	struct tracing_multi_fail *skel;
+	char log_buf[128] = {};
+	int err, fd, prog_fd;
+	LIBBPF_OPTS(bpf_log_opts, log_opts,
+		    .buf = log_buf,
+		    .size = sizeof(log_buf),
+		    .level = 1,
+	);
+	LIBBPF_OPTS(bpf_link_create_opts, opts,
+		    .log_opts = &log_opts,
+		    .flags = flags,
+		    .tracing_multi.ids = ids,
+		    .tracing_multi.cnt = cnt,
+	);
+
+	skel = tracing_multi_fail__open();
+	if (!ASSERT_OK_PTR(skel, "tracing_multi_fail__open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.test_fentry_s, false);
+	err = tracing_multi_fail__load(skel);
+	if (!ASSERT_OK(err, "tracing_multi_fail__load"))
+		goto out;
+
+	prog_fd = bpf_program__fd(skel->progs.test_fentry);
+	fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_FENTRY_MULTI, &opts);
+	if (!ASSERT_LT(fd, 0, "bpf_link_create")) {
+		close(fd);
+		goto out;
+	}
+
+	ASSERT_EQ(fd, err_exp, "err");
+	ASSERT_STREQ(log_buf, msg, "log_buf");
+	ASSERT_EQ(log_opts.true_size, strlen(msg) + 1, "log_size");
+
+out:
+	tracing_multi_fail__destroy(skel);
+}
+
+static void test_multi_log_zero_count(void)
+{
+	const char *msg = "tracing_multi.cnt cannot be zero.\n";
+	__u32 id = 0;
+
+	test_tracing_multi_link_create_log(0, 0, &id, 0, -EINVAL, msg);
+}
+
+static void test_multi_log_missing_ids(void)
+{
+	const char *msg = "tracing_multi.ids must be set.\n";
+
+	test_tracing_multi_link_create_log(0, 0, NULL, 1, -EINVAL, msg);
+}
+
+static void test_multi_log_excessive_count(void)
+{
+	const char *msg = "tracing_multi.cnt is too large.\n";
+	__u32 id = 0;
+
+	test_tracing_multi_link_create_log(0, 0, &id, INT_MAX, -E2BIG, msg);
+}
+
+static void test_multi_log_invalid_flags(void)
+{
+	const char *msg = "Invalid flags.\n";
+	__u32 id = 0;
+
+	test_tracing_multi_link_create_log(0, 1, &id, 1, -EINVAL, msg);
+}
+
+static void test_multi_log_invalid_target_fd(void)
+{
+	const char *msg = "Invalid target_fd.\n";
+	__u32 id = 0;
+
+	test_tracing_multi_link_create_log(-1, 0, &id, 1, -EINVAL, msg);
+}
+
+void test_tracing_multi_link_log(void)
+{
+#ifndef __x86_64__
+	test__skip();
+	return;
+#endif
+
+	if (test__start_subtest("zero_count"))
+		test_multi_log_zero_count();
+	if (test__start_subtest("missing_ids"))
+		test_multi_log_missing_ids();
+	if (test__start_subtest("excessive_count"))
+		test_multi_log_excessive_count();
+	if (test__start_subtest("invalid_flags"))
+		test_multi_log_invalid_flags();
+	if (test__start_subtest("invalid_target_fd"))
+		test_multi_log_invalid_target_fd();
+}
+
-- 
2.55.0