| 1 | |
| 2 |
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| 3 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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| 4 |
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| 5 | #include <linux/string.h>
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| 6 |
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| 7 | #include "../tools/testing/selftests/kselftest_module.h"
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| 8 |
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| 9 | |
| 10 | * Kernel module for testing 'strscpy' family of functions.
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| 11 |
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| 12 |
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| 13 | KSTM_MODULE_GLOBALS();
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| 14 |
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| 15 | |
| 16 | * tc() - Run a specific test case.
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| 17 | * @src: Source string, argument to strscpy_pad()
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| 18 | * @count: Size of destination buffer, argument to strscpy_pad()
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| 19 | * @expected: Expected return value from call to strscpy_pad()
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| 20 | * @terminator: 1 if there should be a terminating null byte 0 otherwise.
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| 21 | * @chars: Number of characters from the src string expected to be
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| 22 | * written to the dst buffer.
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| 23 | * @pad: Number of pad characters expected (in the tail of dst buffer).
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| 24 | * (@pad does not include the null terminator byte.)
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| 25 | *
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| 26 | * Calls strscpy_pad() and verifies the return value and state of the
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| 27 | * destination buffer after the call returns.
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| 28 |
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| 29 | static int __init tc(char *src, int count, int expected,
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| 30 | int chars, int terminator, int pad)
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| 31 | {
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| 32 | int nr_bytes_poison;
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| 33 | int max_expected;
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| 34 | int max_count;
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| 35 | int written;
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| 36 | char buf[6];
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| 37 | int index, i;
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| 38 | const char POISON = 'z';
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| 39 |
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| 40 | total_tests++;
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| 41 |
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| 42 | if (!src) {
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| 43 | pr_err("null source string not supported\n");
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| 44 | return -1;
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| 45 | }
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| 46 |
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| 47 | memset(buf, POISON, sizeof(buf));
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| 48 |
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| 49 | max_count = sizeof(buf) - 2;
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| 50 | max_expected = count - 1;
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| 51 | if (count > max_count) {
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| 52 | pr_err("count (%d) is too big (%d) ... aborting", count, max_count);
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| 53 | return -1;
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| 54 | }
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| 55 | if (expected > max_expected) {
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| 56 | pr_warn("expected (%d) is bigger than can possibly be returned (%d)",
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| 57 | expected, max_expected);
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| 58 | }
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| 59 |
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| 60 | written = strscpy_pad(buf, src, count);
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| 61 | if ((written) != (expected)) {
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| 62 | pr_err("%d != %d (written, expected)\n", written, expected);
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| 63 | goto fail;
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| 64 | }
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| 65 |
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| 66 | if (count && written == -E2BIG) {
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| 67 | if (strncmp(buf, src, count - 1) != 0) {
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| 68 | pr_err("buffer state invalid for -E2BIG\n");
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| 69 | goto fail;
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| 70 | }
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| 71 | if (buf[count - 1] != '\0') {
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| 72 | pr_err("too big string is not null terminated correctly\n");
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| 73 | goto fail;
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| 74 | }
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| 75 | }
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| 76 |
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| 77 | for (i = 0; i < chars; i++) {
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| 78 | if (buf[i] != src[i]) {
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| 79 | pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]);
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| 80 | goto fail;
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| 81 | }
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| 82 | }
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| 83 |
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| 84 | if (terminator) {
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| 85 | if (buf[count - 1] != '\0') {
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| 86 | pr_err("string is not null terminated correctly\n");
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| 87 | goto fail;
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| 88 | }
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| 89 | }
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| 90 |
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| 91 | for (i = 0; i < pad; i++) {
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| 92 | index = chars + terminator + i;
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| 93 | if (buf[index] != '\0') {
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| 94 | pr_err("padding missing at index: %d\n", i);
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| 95 | goto fail;
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| 96 | }
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| 97 | }
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| 98 |
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| 99 | nr_bytes_poison = sizeof(buf) - chars - terminator - pad;
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| 100 | for (i = 0; i < nr_bytes_poison; i++) {
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| 101 | index = sizeof(buf) - 1 - i;
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| 102 | if (buf[index] != POISON) {
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| 103 | pr_err("poison value missing at index: %d\n", i);
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| 104 | goto fail;
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| 105 | }
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| 106 | }
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| 107 |
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| 108 | return 0;
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| 109 | fail:
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| 110 | failed_tests++;
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| 111 | return -1;
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| 112 | }
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| 113 |
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| 114 | static void __init selftest(void)
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| 115 | {
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| 116 | |
| 117 | * tc() uses a destination buffer of size 6 and needs at
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| 118 | * least 2 characters spare (one for null and one to check for
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| 119 | * overflow). This means we should only call tc() with
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| 120 | * strings up to a maximum of 4 characters long and 'count'
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| 121 | * should not exceed 4. To test with longer strings increase
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| 122 | * the buffer size in tc().
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| 123 |
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| 124 |
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| 125 |
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| 126 | KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0));
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| 127 | KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0));
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| 128 |
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| 129 | KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));
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| 130 | KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0));
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| 131 |
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| 132 | KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0));
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| 133 | KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0));
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| 134 | KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1));
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| 135 |
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| 136 | KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0));
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| 137 | KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0));
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| 138 | KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1));
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| 139 | KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2));
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| 140 |
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| 141 | KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0));
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| 142 | KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0));
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| 143 | KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1));
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| 144 | KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2));
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| 145 | KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3));
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| 146 | }
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| 147 |
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| 148 | KSTM_MODULE_LOADERS(test_strscpy);
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| 149 | MODULE_AUTHOR("Tobin C. Harding <[email protected]>");
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| 150 | MODULE_LICENSE("GPL");
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