string: Convert helpers selftest to KUnit

Convert test-string_helpers.c to KUnit so it can be easily run with
everything else.

Failure reporting doesn't need to be open-coded in most places, for
example, forcing a failure in the expected output for upper/lower
testing looks like this:

[12:18:43] # test_upper_lower: EXPECTATION FAILED at lib/string_helpers_kunit.c:579
[12:18:43] Expected dst == strings_upper[i].out, but
[12:18:43] dst == "ABCDEFGH1234567890TEST"
[12:18:43] strings_upper[i].out == "ABCDEFGH1234567890TeST"
[12:18:43] [FAILED] test_upper_lower

Currently passes without problems:

$ ./tools/testing/kunit/kunit.py run string_helpers
...
[12:23:55] Starting KUnit Kernel (1/1)...
[12:23:55] ============================================================
[12:23:55] =============== string_helpers (3 subtests) ================
[12:23:55] [PASSED] test_get_size
[12:23:55] [PASSED] test_upper_lower
[12:23:55] [PASSED] test_unescape
[12:23:55] ================= [PASSED] string_helpers ==================
[12:23:55] ============================================================
[12:23:55] Testing complete. Ran 3 tests: passed: 3
[12:23:55] Elapsed time: 6.709s total, 0.001s configuring, 6.591s building, 0.066s running

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Kees Cook <[e-mail]>

MAINTAINERS

···
 F:	lib/string.c
 F:	lib/string_kunit.c
 F:	lib/string_helpers.c
-F:	lib/test-string_helpers.c
+F:	lib/string_helpers_kunit.c
 F:	scripts/coccinelle/api/string_choices.cocci
 
 GENERIC UIO DRIVER FOR PCI DEVICES

lib/Kconfig.debug

···
 	depends on KUNIT
 	default KUNIT_ALL_TESTS
 
-config TEST_STRING_HELPERS
-	tristate "Test functions located in the string_helpers module at runtime"
+config STRING_HELPERS_KUNIT_TEST
+	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
 
 config TEST_KSTRTOX
 	tristate "Test kstrto*() family of functions at runtime"

lib/Makefile

···
 	 generic-radix-tree.o bitmap-str.o
 obj-$(CONFIG_STRING_KUNIT_TEST) += string_kunit.o
 obj-y += string_helpers.o
-obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
+obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o
 obj-y += hexdump.o
 obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
 obj-y += kstrtox.o

lib/test-string_helpers.c lib/string_helpers_kunit.c

···
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * Test cases for lib/string_helpers.c module.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <kunit/test.h>
 #include <linux/array_size.h>
-#include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/module.h>
 #include <linux/random.h>
 #include <linux/string.h>
 #include <linux/string_helpers.h>
 
-static __init bool test_string_check_buf(const char *name, unsigned int flags,
-					 char *in, size_t p,
-					 char *out_real, size_t q_real,
-					 char *out_test, size_t q_test)
+static void test_string_check_buf(struct kunit *test,
+				  const char *name, unsigned int flags,
+				  char *in, size_t p,
+				  char *out_real, size_t q_real,
+				  char *out_test, size_t q_test)
 {
-	if (q_real == q_test && !memcmp(out_test, out_real, q_test))
-		return true;
-
-	pr_warn("Test '%s' failed: flags = %#x\n", name, flags);
-
-	print_hex_dump(KERN_WARNING, "Input: ", DUMP_PREFIX_NONE, 16, 1,
-		       in, p, true);
-	print_hex_dump(KERN_WARNING, "Expected: ", DUMP_PREFIX_NONE, 16, 1,
-		       out_test, q_test, true);
-	print_hex_dump(KERN_WARNING, "Got: ", DUMP_PREFIX_NONE, 16, 1,
-		       out_real, q_real, true);
-
-	return false;
+	KUNIT_ASSERT_EQ_MSG(test, q_real, q_test, "name:%s", name);
+	KUNIT_EXPECT_MEMEQ_MSG(test, out_test, out_real, q_test,
+			       "name:%s", name);
 }
 
 struct test_string {
···
 	unsigned int flags;
 };
 
-static const struct test_string strings[] __initconst = {
+static const struct test_string strings[] = {
 	{
 		.in = "\\f\\ \\n\\r\\t\\v",
 		.out = "\f\\ \n\r\t\v",
···
 	},
 };
 
-static void __init test_string_unescape(const char *name, unsigned int flags,
-					bool inplace)
+static void test_string_unescape(struct kunit *test,
+				 const char *name, unsigned int flags,
+				 bool inplace)
 {
 	int q_real = 256;
-	char *in = kmalloc(q_real, GFP_KERNEL);
-	char *out_test = kmalloc(q_real, GFP_KERNEL);
-	char *out_real = kmalloc(q_real, GFP_KERNEL);
+	char *in = kunit_kzalloc(test, q_real, GFP_KERNEL);
+	char *out_test = kunit_kzalloc(test, q_real, GFP_KERNEL);
+	char *out_real = kunit_kzalloc(test, q_real, GFP_KERNEL);
 	int i, p = 0, q_test = 0;
 
-	if (!in || !out_test || !out_real)
-		goto out;
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, in);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, out_test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, out_real);
 
 	for (i = 0; i < ARRAY_SIZE(strings); i++) {
 		const char *s = strings[i].in;
···
 		q_real = string_unescape(in, out_real, q_real, flags);
 	}
 
-	test_string_check_buf(name, flags, in, p - 1, out_real, q_real,
+	test_string_check_buf(test, name, flags, in, p - 1, out_real, q_real,
 			      out_test, q_test);
-out:
-	kfree(out_real);
-	kfree(out_test);
-	kfree(in);
 }
 
 struct test_string_1 {
···
 };
 
 #define	TEST_STRING_2_DICT_0		NULL
-static const struct test_string_2 escape0[] __initconst = {{
+static const struct test_string_2 escape0[] = {{
 	.in = "\f\\ \n\r\t\v",
 	.s1 = {{
 		.out = "\\f\\ \\n\\r\\t\\v",
···
 }};
 
 #define	TEST_STRING_2_DICT_1		"b\\ \t\r\xCF"
-static const struct test_string_2 escape1[] __initconst = {{
+static const struct test_string_2 escape1[] = {{
 	.in = "\f\\ \n\r\t\v",
 	.s1 = {{
 		.out = "\f\\134\\040\n\\015\\011\v",
···
 	/* terminator */
 }};
 
-static const struct test_string strings_upper[] __initconst = {
+static const struct test_string strings_upper[] = {
 	{
 		.in = "abcdefgh1234567890test",
 		.out = "ABCDEFGH1234567890TEST",
···
 	},
 };
 
-static const struct test_string strings_lower[] __initconst = {
+static const struct test_string strings_lower[] = {
 	{
 		.in = "ABCDEFGH1234567890TEST",
 		.out = "abcdefgh1234567890test",
···
 	},
 };
 
-static __init const char *test_string_find_match(const struct test_string_2 *s2,
-						 unsigned int flags)
+static const char *test_string_find_match(const struct test_string_2 *s2,
+					  unsigned int flags)
 {
 	const struct test_string_1 *s1 = s2->s1;
 	unsigned int i;
···
 	return NULL;
 }
 
-static __init void
-test_string_escape_overflow(const char *in, int p, unsigned int flags, const char *esc,
+static void
+test_string_escape_overflow(struct kunit *test,
+			    const char *in, int p, unsigned int flags, const char *esc,
 			    int q_test, const char *name)
 {
 	int q_real;
 
 	q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
-	if (q_real != q_test)
-		pr_warn("Test '%s' failed: flags = %#x, osz = 0, expected %d, got %d\n",
-			name, flags, q_test, q_real);
+	KUNIT_EXPECT_EQ_MSG(test, q_real, q_test, "name:%s: flags:%#x", name, flags);
 }
 
-static __init void test_string_escape(const char *name,
-				      const struct test_string_2 *s2,
-				      unsigned int flags, const char *esc)
+static void test_string_escape(struct kunit *test, const char *name,
+			       const struct test_string_2 *s2,
+			       unsigned int flags, const char *esc)
 {
 	size_t out_size = 512;
-	char *out_test = kmalloc(out_size, GFP_KERNEL);
-	char *out_real = kmalloc(out_size, GFP_KERNEL);
-	char *in = kmalloc(256, GFP_KERNEL);
+	char *out_test = kunit_kzalloc(test, out_size, GFP_KERNEL);
+	char *out_real = kunit_kzalloc(test, out_size, GFP_KERNEL);
+	char *in = kunit_kzalloc(test, 256, GFP_KERNEL);
 	int p = 0, q_test = 0;
 	int q_real;
 
-	if (!out_test || !out_real || !in)
-		goto out;
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, out_test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, out_real);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, in);
 
 	for (; s2->in; s2++) {
 		const char *out;
···
 
 	q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
 
-	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
+	test_string_check_buf(test, name, flags, in, p, out_real, q_real, out_test,
 			      q_test);
 
-	test_string_escape_overflow(in, p, flags, esc, q_test, name);
-
-out:
-	kfree(in);
-	kfree(out_real);
-	kfree(out_test);
+	test_string_escape_overflow(test, in, p, flags, esc, q_test, name);
 }
 
 #define string_get_size_maxbuf 16
-#define test_string_get_size_one(size, blk_size, exp_result10, exp_result2)    \
-	do {                                                                   \
-		BUILD_BUG_ON(sizeof(exp_result10) >= string_get_size_maxbuf);  \
-		BUILD_BUG_ON(sizeof(exp_result2) >= string_get_size_maxbuf);   \
-		__test_string_get_size((size), (blk_size), (exp_result10),     \
-				       (exp_result2));                         \
+#define test_string_get_size_one(size, blk_size, exp_result10, exp_result2)      \
+	do {                                                                     \
+		BUILD_BUG_ON(sizeof(exp_result10) >= string_get_size_maxbuf);    \
+		BUILD_BUG_ON(sizeof(exp_result2) >= string_get_size_maxbuf);     \
+		__test_string_get_size(test, (size), (blk_size), (exp_result10), \
+				       (exp_result2));                           \
 	} while (0)
 
 
-static __init void test_string_get_size_check(const char *units,
-					      const char *exp,
-					      char *res,
-					      const u64 size,
-					      const u64 blk_size)
+static void test_string_get_size_check(struct kunit *test,
+				       const char *units,
+				       const char *exp,
+				       char *res,
+				       const u64 size,
+				       const u64 blk_size)
 {
-	if (!memcmp(res, exp, strlen(exp) + 1))
-		return;
-
-	res[string_get_size_maxbuf - 1] = '\0';
-
-	pr_warn("Test 'test_string_get_size' failed!\n");
-	pr_warn("string_get_size(size = %llu, blk_size = %llu, units = %s)\n",
+	KUNIT_EXPECT_MEMEQ_MSG(test, res, exp, strlen(exp) + 1,
+		"string_get_size(size = %llu, blk_size = %llu, units = %s)",
 		size, blk_size, units);
-	pr_warn("expected: '%s', got '%s'\n", exp, res);
 }
 
-static __init void __strchrcut(char *dst, const char *src, const char *cut)
+static void __strchrcut(char *dst, const char *src, const char *cut)
 {
 	const char *from = src;
 	size_t len;
···
 	*dst = '\0';
 }
 
-static __init void __test_string_get_size_one(const u64 size, const u64 blk_size,
-					      const char *exp_result10,
-					      const char *exp_result2,
-					      enum string_size_units units,
-					      const char *cut)
+static void __test_string_get_size_one(struct kunit *test,
+				       const u64 size, const u64 blk_size,
+				       const char *exp_result10,
+				       const char *exp_result2,
+				       enum string_size_units units,
+				       const char *cut)
 {
 	char buf10[string_get_size_maxbuf];
 	char buf2[string_get_size_maxbuf];
···
 	string_get_size(size, blk_size, STRING_UNITS_10 | units, buf10, sizeof(buf10));
 	string_get_size(size, blk_size, STRING_UNITS_2 | units, buf2, sizeof(buf2));
 
-	test_string_get_size_check(prefix10, exp10, buf10, size, blk_size);
-	test_string_get_size_check(prefix2, exp2, buf2, size, blk_size);
+	test_string_get_size_check(test, prefix10, exp10, buf10, size, blk_size);
+	test_string_get_size_check(test, prefix2, exp2, buf2, size, blk_size);
 }
 
-static __init void __test_string_get_size(const u64 size, const u64 blk_size,
-					  const char *exp_result10,
-					  const char *exp_result2)
+static void __test_string_get_size(struct kunit *test,
+				   const u64 size, const u64 blk_size,
+				   const char *exp_result10,
+				   const char *exp_result2)
 {
 	struct {
 		enum string_size_units units;
···
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(get_size_test_cases); i++)
-		__test_string_get_size_one(size, blk_size, exp_result10, exp_result2,
+		__test_string_get_size_one(test, size, blk_size,
+					   exp_result10, exp_result2,
 					   get_size_test_cases[i].units,
 					   get_size_test_cases[i].cut);
 }
 
-static __init void test_string_get_size(void)
+static void test_get_size(struct kunit *test)
 {
 	/* small values */
 	test_string_get_size_one(0, 512, "0 B", "0 B");
···
 	test_string_get_size_one(4096, U64_MAX, "75.6 ZB", "64.0 ZiB");
 }
 
-static void __init test_string_upper_lower(void)
+static void test_upper_lower(struct kunit *test)
 {
 	char *dst;
 	int i;
···
 		int len = strlen(strings_upper[i].in) + 1;
 
 		dst = kmalloc(len, GFP_KERNEL);
-		if (!dst)
-			return;
+		KUNIT_ASSERT_NOT_NULL(test, dst);
 
 		string_upper(dst, s);
-		if (memcmp(dst, strings_upper[i].out, len)) {
-			pr_warn("Test 'string_upper' failed : expected %s, got %s!\n",
-				strings_upper[i].out, dst);
-			kfree(dst);
-			return;
-		}
+		KUNIT_EXPECT_STREQ(test, dst, strings_upper[i].out);
 		kfree(dst);
 	}
 
···
 		int len = strlen(strings_lower[i].in) + 1;
 
 		dst = kmalloc(len, GFP_KERNEL);
-		if (!dst)
-			return;
+		KUNIT_ASSERT_NOT_NULL(test, dst);
 
 		string_lower(dst, s);
-		if (memcmp(dst, strings_lower[i].out, len)) {
-			pr_warn("Test 'string_lower failed : : expected %s, got %s!\n",
-				strings_lower[i].out, dst);
-			kfree(dst);
-			return;
-		}
+		KUNIT_EXPECT_STREQ(test, dst, strings_lower[i].out);
 		kfree(dst);
 	}
 }
 
-static int __init test_string_helpers_init(void)
+static void test_unescape(struct kunit *test)
 {
 	unsigned int i;
 
-	pr_info("Running tests...\n");
 	for (i = 0; i < UNESCAPE_ALL_MASK + 1; i++)
-		test_string_unescape("unescape", i, false);
-	test_string_unescape("unescape inplace",
+		test_string_unescape(test, "unescape", i, false);
+	test_string_unescape(test, "unescape inplace",
 			     get_random_u32_below(UNESCAPE_ALL_MASK + 1), true);
 
 	/* Without dictionary */
 	for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
-		test_string_escape("escape 0", escape0, i, TEST_STRING_2_DICT_0);
+		test_string_escape(test, "escape 0", escape0, i, TEST_STRING_2_DICT_0);
 
 	/* With dictionary */
 	for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
-		test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
-
-	/* Test string_get_size() */
-	test_string_get_size();
-
-	/* Test string upper(), string_lower() */
-	test_string_upper_lower();
-
-	return -EINVAL;
+		test_string_escape(test, "escape 1", escape1, i, TEST_STRING_2_DICT_1);
 }
-module_init(test_string_helpers_init);
+
+static struct kunit_case string_helpers_test_cases[] = {
+	KUNIT_CASE(test_get_size),
+	KUNIT_CASE(test_upper_lower),
+	KUNIT_CASE(test_unescape),
+	{}
+};
+
+static struct kunit_suite string_helpers_test_suite = {
+	.name = "string_helpers",
+	.test_cases = string_helpers_test_cases,
+};
+
+kunit_test_suites(&string_helpers_test_suite);
+
 MODULE_LICENSE("Dual BSD/GPL");