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");
105