// 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"
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