xref: /openbmc/linux/lib/strcat_kunit.c (revision 5d7800d9)
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 
11 static volatile int unconst;
12 
13 static 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 
32 static 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 
59 static 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 
90 static struct kunit_case strcat_test_cases[] = {
91 	KUNIT_CASE(strcat_test),
92 	KUNIT_CASE(strncat_test),
93 	KUNIT_CASE(strlcat_test),
94 	{}
95 };
96 
97 static struct kunit_suite strcat_test_suite = {
98 	.name = "strcat",
99 	.test_cases = strcat_test_cases,
100 };
101 
102 kunit_test_suite(strcat_test_suite);
103 
104 MODULE_LICENSE("GPL");
105