diff options
Diffstat (limited to 'lib/test_strscpy.c')
| -rw-r--r-- | lib/test_strscpy.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/lib/test_strscpy.c b/lib/test_strscpy.c new file mode 100644 index 000000000000..a827f94601f5 --- /dev/null +++ b/lib/test_strscpy.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0+ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/string.h> + +#include "../tools/testing/selftests/kselftest_module.h" + +/* + * Kernel module for testing 'strscpy' family of functions. + */ + +KSTM_MODULE_GLOBALS(); + +/* + * 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 int __init tc(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'; + + total_tests++; + + if (!src) { + pr_err("null source string not supported\n"); + return -1; + } + + 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 */ + if (count > max_count) { + pr_err("count (%d) is too big (%d) ... aborting", count, max_count); + return -1; + } + if (expected > max_expected) { + pr_warn("expected (%d) is bigger than can possibly be returned (%d)", + expected, max_expected); + } + + written = strscpy_pad(buf, src, count); + if ((written) != (expected)) { + pr_err("%d != %d (written, expected)\n", written, expected); + goto fail; + } + + if (count && written == -E2BIG) { + if (strncmp(buf, src, count - 1) != 0) { + pr_err("buffer state invalid for -E2BIG\n"); + goto fail; + } + if (buf[count - 1] != '\0') { + pr_err("too big string is not null terminated correctly\n"); + goto fail; + } + } + + for (i = 0; i < chars; i++) { + if (buf[i] != src[i]) { + pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]); + goto fail; + } + } + + if (terminator) { + if (buf[count - 1] != '\0') { + pr_err("string is not null terminated correctly\n"); + goto fail; + } + } + + for (i = 0; i < pad; i++) { + index = chars + terminator + i; + if (buf[index] != '\0') { + pr_err("padding missing at index: %d\n", i); + goto fail; + } + } + + 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 */ + if (buf[index] != POISON) { + pr_err("poison value missing at index: %d\n", i); + goto fail; + } + } + + return 0; +fail: + failed_tests++; + return -1; +} + +static void __init selftest(void) +{ + /* + * 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(src, count, expected, chars, terminator, pad) */ + KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0)); + KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0)); + + KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0)); + KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0)); + + KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0)); + KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0)); + KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1)); + + KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0)); + KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0)); + KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1)); + KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2)); + + KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0)); + KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0)); + KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1)); + KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2)); + KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3)); +} + +KSTM_MODULE_LOADERS(test_strscpy); +MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>"); +MODULE_LICENSE("GPL"); |