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Diffstat (limited to 'lib/strscpy_kunit.c')
| -rw-r--r-- | lib/strscpy_kunit.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/lib/strscpy_kunit.c b/lib/strscpy_kunit.c new file mode 100644 index 000000000000..a6b6344354ed --- /dev/null +++ b/lib/strscpy_kunit.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Kernel module for testing 'strscpy' family of functions. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <kunit/test.h> +#include <linux/string.h> + +/* + * tc() - Run a specific test case. + * @src: Source string, argument to strscpy_pad() + * @count: Size of destination buffer, argument to strscpy_pad() + * @expected: Expected return value from call to strscpy_pad() + * @terminator: 1 if there should be a terminating null byte 0 otherwise. + * @chars: Number of characters from the src string expected to be + * written to the dst buffer. + * @pad: Number of pad characters expected (in the tail of dst buffer). + * (@pad does not include the null terminator byte.) + * + * Calls strscpy_pad() and verifies the return value and state of the + * destination buffer after the call returns. + */ +static void tc(struct kunit *test, char *src, int count, int expected, + int chars, int terminator, int pad) +{ + int nr_bytes_poison; + int max_expected; + int max_count; + int written; + char buf[6]; + int index, i; + const char POISON = 'z'; + + KUNIT_ASSERT_TRUE_MSG(test, src != NULL, + "null source string not supported"); + + memset(buf, POISON, sizeof(buf)); + /* Future proofing test suite, validate args */ + max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */ + max_expected = count - 1; /* Space for the null */ + + KUNIT_ASSERT_LE_MSG(test, count, max_count, + "count (%d) is too big (%d) ... aborting", count, max_count); + KUNIT_EXPECT_LE_MSG(test, expected, max_expected, + "expected (%d) is bigger than can possibly be returned (%d)", + expected, max_expected); + + written = strscpy_pad(buf, src, count); + KUNIT_ASSERT_EQ(test, written, expected); + + if (count && written == -E2BIG) { + KUNIT_ASSERT_EQ_MSG(test, 0, strncmp(buf, src, count - 1), + "buffer state invalid for -E2BIG"); + KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0', + "too big string is not null terminated correctly"); + } + + for (i = 0; i < chars; i++) + KUNIT_ASSERT_EQ_MSG(test, buf[i], src[i], + "buf[i]==%c != src[i]==%c", buf[i], src[i]); + + if (terminator) + KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0', + "string is not null terminated correctly"); + + for (i = 0; i < pad; i++) { + index = chars + terminator + i; + KUNIT_ASSERT_EQ_MSG(test, buf[index], '\0', + "padding missing at index: %d", i); + } + + nr_bytes_poison = sizeof(buf) - chars - terminator - pad; + for (i = 0; i < nr_bytes_poison; i++) { + index = sizeof(buf) - 1 - i; /* Check from the end back */ + KUNIT_ASSERT_EQ_MSG(test, buf[index], POISON, + "poison value missing at index: %d", i); + } +} + +static void strscpy_test(struct kunit *test) +{ + char dest[8]; + + /* + * tc() uses a destination buffer of size 6 and needs at + * least 2 characters spare (one for null and one to check for + * overflow). This means we should only call tc() with + * strings up to a maximum of 4 characters long and 'count' + * should not exceed 4. To test with longer strings increase + * the buffer size in tc(). + */ + + /* tc(test, src, count, expected, chars, terminator, pad) */ + tc(test, "a", 0, -E2BIG, 0, 0, 0); + tc(test, "", 0, -E2BIG, 0, 0, 0); + + tc(test, "a", 1, -E2BIG, 0, 1, 0); + tc(test, "", 1, 0, 0, 1, 0); + + tc(test, "ab", 2, -E2BIG, 1, 1, 0); + tc(test, "a", 2, 1, 1, 1, 0); + tc(test, "", 2, 0, 0, 1, 1); + + tc(test, "abc", 3, -E2BIG, 2, 1, 0); + tc(test, "ab", 3, 2, 2, 1, 0); + tc(test, "a", 3, 1, 1, 1, 1); + tc(test, "", 3, 0, 0, 1, 2); + + tc(test, "abcd", 4, -E2BIG, 3, 1, 0); + tc(test, "abc", 4, 3, 3, 1, 0); + tc(test, "ab", 4, 2, 2, 1, 1); + tc(test, "a", 4, 1, 1, 1, 2); + tc(test, "", 4, 0, 0, 1, 3); + + /* Compile-time-known source strings. */ + KUNIT_EXPECT_EQ(test, strscpy(dest, "", ARRAY_SIZE(dest)), 0); + KUNIT_EXPECT_EQ(test, strscpy(dest, "", 3), 0); + KUNIT_EXPECT_EQ(test, strscpy(dest, "", 1), 0); + KUNIT_EXPECT_EQ(test, strscpy(dest, "", 0), -E2BIG); + KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", ARRAY_SIZE(dest)), 5); + KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 3), -E2BIG); + KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 1), -E2BIG); + KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 0), -E2BIG); + KUNIT_EXPECT_EQ(test, strscpy(dest, "This is too long", ARRAY_SIZE(dest)), -E2BIG); +} + +static struct kunit_case strscpy_test_cases[] = { + KUNIT_CASE(strscpy_test), + {} +}; + +static struct kunit_suite strscpy_test_suite = { + .name = "strscpy", + .test_cases = strscpy_test_cases, +}; + +kunit_test_suite(strscpy_test_suite); + +MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>"); +MODULE_LICENSE("GPL"); |