1 // SPDX-License-Identifier: GPL-2.0+
3 * Kernel module for testing 'strscpy' family of functions.
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 #include <kunit/test.h>
9 #include <linux/string.h>
12 * tc() - Run a specific test case.
13 * @src: Source string, argument to strscpy_pad()
14 * @count: Size of destination buffer, argument to strscpy_pad()
15 * @expected: Expected return value from call to strscpy_pad()
16 * @terminator: 1 if there should be a terminating null byte 0 otherwise.
17 * @chars: Number of characters from the src string expected to be
18 * written to the dst buffer.
19 * @pad: Number of pad characters expected (in the tail of dst buffer).
20 * (@pad does not include the null terminator byte.)
22 * Calls strscpy_pad() and verifies the return value and state of the
23 * destination buffer after the call returns.
25 static void tc(struct kunit
*test
, char *src
, int count
, int expected
,
26 int chars
, int terminator
, int pad
)
34 const char POISON
= 'z';
36 KUNIT_ASSERT_TRUE_MSG(test
, src
!= NULL
,
37 "null source string not supported");
39 memset(buf
, POISON
, sizeof(buf
));
40 /* Future proofing test suite, validate args */
41 max_count
= sizeof(buf
) - 2; /* Space for null and to verify overflow */
42 max_expected
= count
- 1; /* Space for the null */
44 KUNIT_ASSERT_LE_MSG(test
, count
, max_count
,
45 "count (%d) is too big (%d) ... aborting", count
, max_count
);
46 KUNIT_EXPECT_LE_MSG(test
, expected
, max_expected
,
47 "expected (%d) is bigger than can possibly be returned (%d)",
48 expected
, max_expected
);
50 written
= strscpy_pad(buf
, src
, count
);
51 KUNIT_ASSERT_EQ(test
, written
, expected
);
53 if (count
&& written
== -E2BIG
) {
54 KUNIT_ASSERT_EQ_MSG(test
, 0, strncmp(buf
, src
, count
- 1),
55 "buffer state invalid for -E2BIG");
56 KUNIT_ASSERT_EQ_MSG(test
, buf
[count
- 1], '\0',
57 "too big string is not null terminated correctly");
60 for (i
= 0; i
< chars
; i
++)
61 KUNIT_ASSERT_EQ_MSG(test
, buf
[i
], src
[i
],
62 "buf[i]==%c != src[i]==%c", buf
[i
], src
[i
]);
65 KUNIT_ASSERT_EQ_MSG(test
, buf
[count
- 1], '\0',
66 "string is not null terminated correctly");
68 for (i
= 0; i
< pad
; i
++) {
69 index
= chars
+ terminator
+ i
;
70 KUNIT_ASSERT_EQ_MSG(test
, buf
[index
], '\0',
71 "padding missing at index: %d", i
);
74 nr_bytes_poison
= sizeof(buf
) - chars
- terminator
- pad
;
75 for (i
= 0; i
< nr_bytes_poison
; i
++) {
76 index
= sizeof(buf
) - 1 - i
; /* Check from the end back */
77 KUNIT_ASSERT_EQ_MSG(test
, buf
[index
], POISON
,
78 "poison value missing at index: %d", i
);
82 static void strscpy_test(struct kunit
*test
)
87 * tc() uses a destination buffer of size 6 and needs at
88 * least 2 characters spare (one for null and one to check for
89 * overflow). This means we should only call tc() with
90 * strings up to a maximum of 4 characters long and 'count'
91 * should not exceed 4. To test with longer strings increase
92 * the buffer size in tc().
95 /* tc(test, src, count, expected, chars, terminator, pad) */
96 tc(test
, "a", 0, -E2BIG
, 0, 0, 0);
97 tc(test
, "", 0, -E2BIG
, 0, 0, 0);
99 tc(test
, "a", 1, -E2BIG
, 0, 1, 0);
100 tc(test
, "", 1, 0, 0, 1, 0);
102 tc(test
, "ab", 2, -E2BIG
, 1, 1, 0);
103 tc(test
, "a", 2, 1, 1, 1, 0);
104 tc(test
, "", 2, 0, 0, 1, 1);
106 tc(test
, "abc", 3, -E2BIG
, 2, 1, 0);
107 tc(test
, "ab", 3, 2, 2, 1, 0);
108 tc(test
, "a", 3, 1, 1, 1, 1);
109 tc(test
, "", 3, 0, 0, 1, 2);
111 tc(test
, "abcd", 4, -E2BIG
, 3, 1, 0);
112 tc(test
, "abc", 4, 3, 3, 1, 0);
113 tc(test
, "ab", 4, 2, 2, 1, 1);
114 tc(test
, "a", 4, 1, 1, 1, 2);
115 tc(test
, "", 4, 0, 0, 1, 3);
117 /* Compile-time-known source strings. */
118 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "", ARRAY_SIZE(dest
)), 0);
119 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "", 3), 0);
120 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "", 1), 0);
121 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "", 0), -E2BIG
);
122 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "Fixed", ARRAY_SIZE(dest
)), 5);
123 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "Fixed", 3), -E2BIG
);
124 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "Fixed", 1), -E2BIG
);
125 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "Fixed", 0), -E2BIG
);
126 KUNIT_EXPECT_EQ(test
, strscpy(dest
, "This is too long", ARRAY_SIZE(dest
)), -E2BIG
);
129 static struct kunit_case strscpy_test_cases
[] = {
130 KUNIT_CASE(strscpy_test
),
134 static struct kunit_suite strscpy_test_suite
= {
136 .test_cases
= strscpy_test_cases
,
139 kunit_test_suite(strscpy_test_suite
);
141 MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>");
142 MODULE_LICENSE("GPL");