tools/testing/selftests/bpf/prog_tests/read_vsyscall.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
Extension
.c
Size
1607 bytes
Lines
60
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: syscall or user/kernel boundary
Status
core implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct read_ret_desc {
	const char *name;
	int ret;
} all_read[] = {
	{ .name = "probe_read_kernel", .ret = -ERANGE },
	{ .name = "probe_read_kernel_str", .ret = -ERANGE },
	{ .name = "probe_read", .ret = -ERANGE },
	{ .name = "probe_read_str", .ret = -ERANGE },
	{ .name = "probe_read_user", .ret = -EFAULT },
	{ .name = "probe_read_user_str", .ret = -EFAULT },
	{ .name = "copy_from_user", .ret = -EFAULT },
	{ .name = "copy_from_user_task", .ret = -EFAULT },
	{ .name = "copy_from_user_str", .ret = -EFAULT },
	{ .name = "copy_from_user_task_str", .ret = -EFAULT },
};

void test_read_vsyscall(void)
{
	struct read_vsyscall *skel;
	unsigned int i;
	int err;

#if !defined(__x86_64__)
	test__skip();
	return;
#endif
	skel = read_vsyscall__open_and_load();
	if (!ASSERT_OK_PTR(skel, "read_vsyscall open_load"))
		return;

	skel->bss->target_pid = getpid();
	err = read_vsyscall__attach(skel);
	if (!ASSERT_EQ(err, 0, "read_vsyscall attach"))
		goto out;

	/* userspace may don't have vsyscall page due to LEGACY_VSYSCALL_NONE,
	 * but it doesn't affect the returned error codes.
	 */
	skel->bss->user_ptr = (void *)VSYSCALL_ADDR;
	usleep(1);

	for (i = 0; i < ARRAY_SIZE(all_read); i++)
		ASSERT_EQ(skel->bss->read_ret[i], all_read[i].ret, all_read[i].name);
out:
	read_vsyscall__destroy(skel);
}

Annotation

Implementation Notes