// SPDX-License-Identifier: GPL-2.0
/*
 * KUnit test of proc sysctl.
 */

#include <kunit/test.h>
#include <linux/printk.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>

static int i_zero;
static int i_one_hundred = 100;

struct test_sysctl_data {
	int int_0001;
	int int_0002;
	int int_0003[4];

	unsigned int uint_0001;

	char string_0001[65];
};

static struct test_sysctl_data test_data = {
	.int_0001 = 60,
	.int_0002 = 1,

	.int_0003[0] = 0,
	.int_0003[1] = 1,
	.int_0003[2] = 2,
	.int_0003[3] = 3,

	.uint_0001 = 314,

	.string_0001 = "(none)",
};

static void sysctl_test_dointvec_null_tbl_data(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void  *buffer = kunit_kzalloc(test, sizeof(int), GFP_USER);
	size_t len;
	loff_t pos;

	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 0, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

static void sysctl_test_dointvec_table_maxlen_unset(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= 0,
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void  *buffer = kunit_kzalloc(test, sizeof(int), GFP_USER);
	size_t len;
	loff_t pos;

	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 0, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

static void sysctl_test_dointvec_table_len_is_zero(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void  *buffer = kunit_kzalloc(test, sizeof(int), GFP_USER);
	size_t len;
	loff_t pos;

	len = 0;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 0, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

static void sysctl_test_dointvec_table_read_but_position_set(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void  *buffer = kunit_kzalloc(test, sizeof(int), GFP_USER);
	size_t len;
	loff_t pos;

	len = 1234;
	pos = 1;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 0, buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

static void sysctl_test_dointvec_happy_single_positive(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[] = "9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;

	table.data = kunit_kzalloc(test, sizeof(int), GFP_USER);
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, input, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
	KUNIT_EXPECT_EQ(test, 9, *(int *)table.data);
}

static void sysctl_test_dointvec_happy_single_negative(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[] = "-9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;

	table.data = kunit_kzalloc(test, sizeof(int), GFP_USER);
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, input, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
	KUNIT_EXPECT_EQ(test, -9, *(int *)table.data);
}

static void sysctl_test_dointvec_single_less_int_min(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[32];
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
					     - (INT_MAX + INT_MIN) + 1;

	KUNIT_EXPECT_LT(test,
			snprintf(input, sizeof(input), "-%lu",
				 abs_of_less_than_min),
			sizeof(input));

	table.data = kunit_kzalloc(test, sizeof(int), GFP_USER);
	KUNIT_EXPECT_EQ(test, -EINVAL,
			proc_dointvec(&table, 1, input, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, 0, *(int *)table.data);
}

static void sysctl_test_dointvec_single_greater_int_max(struct kunit *test)
{
	struct ctl_table table = {
		.procname = "foo",
		.data		= &test_data.int_0001,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[32];
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	unsigned long greater_than_max = (unsigned long)INT_MAX + 1;

	KUNIT_EXPECT_GT(test, greater_than_max, INT_MAX);
	KUNIT_EXPECT_LT(test, snprintf(input, sizeof(input), "%lu",
				       greater_than_max),
			sizeof(input));
	table.data = kunit_kzalloc(test, sizeof(int), GFP_USER);
	KUNIT_EXPECT_EQ(test, -EINVAL,
			proc_dointvec(&table, 1, input, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, 0, *(int *)table.data);
}

static int sysctl_test_init(struct kunit *test)
{
	return 0;
}

/*
 * This is run once after each test case, see the comment on example_test_module
 * for more information.
 */
static void sysctl_test_exit(struct kunit *test)
{
}

/*
 * Here we make a list of all the test cases we want to add to the test module
 * below.
 */
static struct kunit_case sysctl_test_cases[] = {
	/*
	 * This is a helper to create a test case object from a test case
	 * function; its exact function is not important to understand how to
	 * use KUnit, just know that this is how you associate test cases with a
	 * test module.
	 */
	KUNIT_CASE(sysctl_test_dointvec_null_tbl_data),
	KUNIT_CASE(sysctl_test_dointvec_table_maxlen_unset),
	KUNIT_CASE(sysctl_test_dointvec_table_len_is_zero),
	KUNIT_CASE(sysctl_test_dointvec_table_read_but_position_set),
	KUNIT_CASE(sysctl_test_dointvec_happy_single_positive),
	KUNIT_CASE(sysctl_test_dointvec_happy_single_negative),
	KUNIT_CASE(sysctl_test_dointvec_single_less_int_min),
	KUNIT_CASE(sysctl_test_dointvec_single_greater_int_max),
	{},
};

/*
 * This defines a suite or grouping of tests.
 *
 * Test cases are defined as belonging to the suite by adding them to
 * `test_cases`.
 *
 * Often it is desirable to run some function which will set up things which
 * will be used by every test; this is accomplished with an `init` function
 * which runs before each test case is invoked. Similarly, an `exit` function
 * may be specified which runs after every test case and can be used to for
 * cleanup. For clarity, running tests in a test module would behave as follows:
 *
 * module.init(test);
 * module.test_case[0](test);
 * module.exit(test);
 * module.init(test);
 * module.test_case[1](test);
 * module.exit(test);
 * ...;
 */
static struct kunit_module sysctl_test_module = {
	.name = "sysctl_test",
	.init = sysctl_test_init,
	.exit = sysctl_test_exit,
	.test_cases = sysctl_test_cases,
};

/*
 * This registers the above test module telling KUnit that this is a suite of
 * tests that need to be run.
 */
module_test(sysctl_test_module);