1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Kernel module for testing 'strcat' family of functions.
  4 */
  5
  6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  7
  8#include <kunit/test.h>
  9#include <linux/string.h>
 10
 11static volatile int unconst;
 12
 13static void strcat_test(struct kunit *test)
 14{
 15	char dest[8];
 16
 17	/* Destination is terminated. */
 18	memset(dest, 0, sizeof(dest));
 19	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
 20	/* Empty copy does nothing. */
 21	KUNIT_EXPECT_TRUE(test, strcat(dest, "") == dest);
 22	KUNIT_EXPECT_STREQ(test, dest, "");
 23	/* 4 characters copied in, stops at %NUL. */
 24	KUNIT_EXPECT_TRUE(test, strcat(dest, "four\000123") == dest);
 25	KUNIT_EXPECT_STREQ(test, dest, "four");
 26	KUNIT_EXPECT_EQ(test, dest[5], '\0');
 27	/* 2 more characters copied in okay. */
 28	KUNIT_EXPECT_TRUE(test, strcat(dest, "AB") == dest);
 29	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
 30}
 31
 32static void strncat_test(struct kunit *test)
 33{
 34	char dest[8];
 35
 36	/* Destination is terminated. */
 37	memset(dest, 0, sizeof(dest));
 38	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
 39	/* Empty copy of size 0 does nothing. */
 40	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 0 + unconst) == dest);
 41	KUNIT_EXPECT_STREQ(test, dest, "");
 42	/* Empty copy of size 1 does nothing too. */
 43	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 1 + unconst) == dest);
 44	KUNIT_EXPECT_STREQ(test, dest, "");
 45	/* Copy of max 0 characters should do nothing. */
 46	KUNIT_EXPECT_TRUE(test, strncat(dest, "asdf", 0 + unconst) == dest);
 47	KUNIT_EXPECT_STREQ(test, dest, "");
 48
 49	/* 4 characters copied in, even if max is 8. */
 50	KUNIT_EXPECT_TRUE(test, strncat(dest, "four\000123", 8 + unconst) == dest);
 51	KUNIT_EXPECT_STREQ(test, dest, "four");
 52	KUNIT_EXPECT_EQ(test, dest[5], '\0');
 53	KUNIT_EXPECT_EQ(test, dest[6], '\0');
 54	/* 2 characters copied in okay, 2 ignored. */
 55	KUNIT_EXPECT_TRUE(test, strncat(dest, "ABCD", 2 + unconst) == dest);
 56	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
 57}
 58
 59static void strlcat_test(struct kunit *test)
 60{
 61	char dest[8] = "";
 62	int len = sizeof(dest) + unconst;
 63
 64	/* Destination is terminated. */
 65	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
 66	/* Empty copy is size 0. */
 67	KUNIT_EXPECT_EQ(test, strlcat(dest, "", len), 0);
 68	KUNIT_EXPECT_STREQ(test, dest, "");
 69	/* Size 1 should keep buffer terminated, report size of source only. */
 70	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", 1 + unconst), 4);
 71	KUNIT_EXPECT_STREQ(test, dest, "");
 72
 73	/* 4 characters copied in. */
 74	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", len), 4);
 75	KUNIT_EXPECT_STREQ(test, dest, "four");
 76	/* 2 characters copied in okay, gets to 6 total. */
 77	KUNIT_EXPECT_EQ(test, strlcat(dest, "AB", len), 6);
 78	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
 79	/* 2 characters ignored if max size (7) reached. */
 80	KUNIT_EXPECT_EQ(test, strlcat(dest, "CD", 7 + unconst), 8);
 81	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
 82	/* 1 of 2 characters skipped, now at true max size. */
 83	KUNIT_EXPECT_EQ(test, strlcat(dest, "EFG", len), 9);
 84	KUNIT_EXPECT_STREQ(test, dest, "fourABE");
 85	/* Everything else ignored, now at full size. */
 86	KUNIT_EXPECT_EQ(test, strlcat(dest, "1234", len), 11);
 87	KUNIT_EXPECT_STREQ(test, dest, "fourABE");
 88}
 89
 90static struct kunit_case strcat_test_cases[] = {
 91	KUNIT_CASE(strcat_test),
 92	KUNIT_CASE(strncat_test),
 93	KUNIT_CASE(strlcat_test),
 94	{}
 95};
 96
 97static struct kunit_suite strcat_test_suite = {
 98	.name = "strcat",
 99	.test_cases = strcat_test_cases,
100};
101
102kunit_test_suite(strcat_test_suite);
103
104MODULE_LICENSE("GPL");