projects/linux·blob v6.3 · refs

142 lines · 4.5 KiB

1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Kernel module for testing 'strscpy' 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/*
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.)
21 *
22 * Calls strscpy_pad() and verifies the return value and state of the
23 * destination buffer after the call returns.
24 */
25static void tc(struct kunit *test, char *src, int count, int expected,
26 int chars, int terminator, int pad)
27{
28 int nr_bytes_poison;
29 int max_expected;
30 int max_count;
31 int written;
32 char buf[6];
33 int index, i;
34 const char POISON = 'z';
35
36 KUNIT_ASSERT_TRUE_MSG(test, src != NULL,
37 "null source string not supported");
38
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 */
43
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);
49
50 written = strscpy_pad(buf, src, count);
51 KUNIT_ASSERT_EQ(test, written, expected);
52
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");
58 }
59
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]);
63
64 if (terminator)
65 KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0',
66 "string is not null terminated correctly");
67
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);
72 }
73
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);
79 }
80}
81
82static void strscpy_test(struct kunit *test)
83{
84 char dest[8];
85
86 /*
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().
93 */
94
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);
98
99 tc(test, "a", 1, -E2BIG, 0, 1, 0);
100 tc(test, "", 1, 0, 0, 1, 0);
101
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);
105
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);
110
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);
116
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);
127}
128
129static struct kunit_case strscpy_test_cases[] = {
130 KUNIT_CASE(strscpy_test),
131 {}
132};
133
134static struct kunit_suite strscpy_test_suite = {
135 .name = "strscpy",
136 .test_cases = strscpy_test_cases,
137};
138
139kunit_test_suite(strscpy_test_suite);
140
141MODULE_AUTHOR("Tobin C. Harding <[email protected]>");
142MODULE_LICENSE("GPL");