linux/tools/testing/selftests/bpf/prog_tests/test_strncmp.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
#include <test_progs.h>
#include "strncmp_test.skel.h"

static int trigger_strncmp(const struct strncmp_test *skel)
{
	int cmp;

	usleep(1);

	cmp = skel->bss->cmp_ret;
	if (cmp > 0)
		return 1;
	if (cmp < 0)
		return -1;
	return 0;
}

/*
 * Compare str and target after making str[i] != target[i].
 * When exp is -1, make str[i] < target[i] and delta = -1.
 */
static void strncmp_full_str_cmp(struct strncmp_test *skel, const char *name,
				 int exp)
{
	size_t nr = sizeof(skel->bss->str);
	char *str = skel->bss->str;
	int delta = exp;
	int got;
	size_t i;

	memcpy(str, skel->rodata->target, nr);
	for (i = 0; i < nr - 1; i++) {
		str[i] += delta;

		got = trigger_strncmp(skel);
		ASSERT_EQ(got, exp, name);

		str[i] -= delta;
	}
}

static void test_strncmp_ret(void)
{
	struct strncmp_test *skel;
	int err, got;

	skel = strncmp_test__open();
	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
		return;

	bpf_program__set_autoload(skel->progs.do_strncmp, true);

	err = strncmp_test__load(skel);
	if (!ASSERT_EQ(err, 0, "strncmp_test load"))
		goto out;

	err = strncmp_test__attach(skel);
	if (!ASSERT_EQ(err, 0, "strncmp_test attach"))
		goto out;

	skel->bss->target_pid = getpid();

	/* Empty str */
	skel->bss->str[0] = '\0';
	got = trigger_strncmp(skel);
	ASSERT_EQ(got, -1, "strncmp: empty str");

	/* Same string */
	memcpy(skel->bss->str, skel->rodata->target, sizeof(skel->bss->str));
	got = trigger_strncmp(skel);
	ASSERT_EQ(got, 0, "strncmp: same str");

	/* Not-null-termainted string  */
	memcpy(skel->bss->str, skel->rodata->target, sizeof(skel->bss->str));
	skel->bss->str[sizeof(skel->bss->str) - 1] = 'A';
	got = trigger_strncmp(skel);
	ASSERT_EQ(got, 1, "strncmp: not-null-term str");

	strncmp_full_str_cmp(skel, "strncmp: less than", -1);
	strncmp_full_str_cmp(skel, "strncmp: greater than", 1);
out:
	strncmp_test__destroy(skel);
}

static void test_strncmp_bad_not_const_str_size(void)
{
	struct strncmp_test *skel;
	int err;

	skel = strncmp_test__open();
	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
		return;

	bpf_program__set_autoload(skel->progs.strncmp_bad_not_const_str_size, true);

	err = strncmp_test__load(skel);
	ASSERT_ERR(err, "strncmp_test load bad_not_const_str_size");

	strncmp_test__destroy(skel);
}

static void test_strncmp_bad_writable_target(void)
{
	struct strncmp_test *skel;
	int err;

	skel = strncmp_test__open();
	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
		return;

	bpf_program__set_autoload(skel->progs.strncmp_bad_writable_target, true);

	err = strncmp_test__load(skel);
	ASSERT_ERR(err, "strncmp_test load bad_writable_target");

	strncmp_test__destroy(skel);
}

static void test_strncmp_bad_not_null_term_target(void)
{
	struct strncmp_test *skel;
	int err;

	skel = strncmp_test__open();
	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
		return;

	bpf_program__set_autoload(skel->progs.strncmp_bad_not_null_term_target, true);

	err = strncmp_test__load(skel);
	ASSERT_ERR(err, "strncmp_test load bad_not_null_term_target");

	strncmp_test__destroy(skel);
}

void test_test_strncmp(void)
{
	if (test__start_subtest("strncmp_ret"))
		test_strncmp_ret();
	if (test__start_subtest("strncmp_bad_not_const_str_size"))
		test_strncmp_bad_not_const_str_size();
	if (test__start_subtest("strncmp_bad_writable_target"))
		test_strncmp_bad_writable_target();
	if (test__start_subtest("strncmp_bad_not_null_term_target"))
		test_strncmp_bad_not_null_term_target();
}