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
strcat_test(struct kunit * test)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
strncat_test(struct kunit * test)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
strlcat_test(struct kunit * test)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