From: David Laight Date: Mon, 2 Mar 2026 10:17:57 +0000 (+0000) Subject: selftests/nolibc: Use length of 'expected' string to check snprintf() output X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f36e1ec61a6adb135d1b4021bc849c6acb96f50c;p=thirdparty%2Fkernel%2Flinux.git selftests/nolibc: Use length of 'expected' string to check snprintf() output Instead of requiring the test cases specifying both the length and expected output, take the length from the expected output. Tests that expect the output be truncated are changed to specify the un-truncated output. Change the strncmp() to a memcmp() with an extra check that the output is actually terminated. Append a '+' to the printed output (after the final ") when the output is truncated. Signed-off-by: David Laight Acked-by: Willy Tarreau Link: https://patch.msgid.link/20260302101815.3043-6-david.laight.linux@gmail.com Signed-off-by: Thomas Weißschuh --- diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index bfe793caa9637..154cc5711a4c9 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1668,29 +1668,44 @@ int run_stdlib(int min, int max) return ret; } -#define EXPECT_VFPRINTF(c, expected, fmt, ...) \ - ret += expect_vfprintf(llen, c, expected, fmt, ##__VA_ARGS__) +#define EXPECT_VFPRINTF(expected, fmt, ...) \ + ret += expect_vfprintf(llen, expected, fmt, ##__VA_ARGS__) -static int expect_vfprintf(int llen, int c, const char *expected, const char *fmt, ...) +#define VFPRINTF_LEN 20 +static int expect_vfprintf(int llen, const char *expected, const char *fmt, ...) { - char buf[100]; + char buf[VFPRINTF_LEN + 80]; + unsigned int cmp_len; va_list args; - ssize_t w; + ssize_t w, expected_len; va_start(args, fmt); - /* Only allow writing 21 bytes, to test truncation */ - w = vsnprintf(buf, 21, fmt, args); + /* Limit buffer length to test truncation */ + w = vsnprintf(buf, VFPRINTF_LEN + 1, fmt, args); va_end(args); llen += printf(" \"%s\"", buf); - if (strncmp(expected, buf, c)) { - llen += printf(" should be \"%s\"", expected); + + expected_len = strlen(expected); + if (expected_len > VFPRINTF_LEN) { + /* Indicate truncated in test output */ + llen += printf("+"); + cmp_len = VFPRINTF_LEN; + } else { + cmp_len = expected_len; + } + + if (memcmp(expected, buf, cmp_len) || buf[cmp_len]) { + /* Copy and truncate until "%.*s" supported */ + memcpy(buf, expected, cmp_len); + buf[cmp_len] = 0; + llen += printf(" should be \"%s\"", buf); result(llen, FAIL); return 1; } - if (w != c) { - llen += printf(" written(%d) != %d", (int)w, c); + if (w != expected_len) { + llen += printf(" written(%d) != %d", (int)w, (int)expected_len); result(llen, FAIL); return 1; } @@ -1817,21 +1832,21 @@ static int run_printf(int min, int max) * test numbers. */ switch (test + __LINE__ + 1) { - CASE_TEST(empty); EXPECT_VFPRINTF(0, "", ""); break; - CASE_TEST(simple); EXPECT_VFPRINTF(3, "foo", "foo"); break; - CASE_TEST(string); EXPECT_VFPRINTF(3, "foo", "%s", "foo"); break; - CASE_TEST(number); EXPECT_VFPRINTF(4, "1234", "%d", 1234); break; - CASE_TEST(negnumber); EXPECT_VFPRINTF(5, "-1234", "%d", -1234); break; - CASE_TEST(unsigned); EXPECT_VFPRINTF(5, "12345", "%u", 12345); break; - CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break; - CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break; - CASE_TEST(pointer); EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break; - CASE_TEST(uintmax_t); EXPECT_VFPRINTF(20, "18446744073709551615", "%ju", 0xffffffffffffffffULL); break; - CASE_TEST(intmax_t); EXPECT_VFPRINTF(20, "-9223372036854775807", "%jd", 0x8000000000000001LL); break; - CASE_TEST(truncation); EXPECT_VFPRINTF(25, "01234567890123456789", "%s", "0123456789012345678901234"); break; - CASE_TEST(string_width); EXPECT_VFPRINTF(10, " 1", "%10s", "1"); break; - CASE_TEST(number_width); EXPECT_VFPRINTF(10, " 1", "%10d", 1); break; - CASE_TEST(width_trunc); EXPECT_VFPRINTF(25, " ", "%25d", 1); break; + CASE_TEST(empty); EXPECT_VFPRINTF("", ""); break; + CASE_TEST(simple); EXPECT_VFPRINTF("foo", "foo"); break; + CASE_TEST(string); EXPECT_VFPRINTF("foo", "%s", "foo"); break; + CASE_TEST(number); EXPECT_VFPRINTF("1234", "%d", 1234); break; + CASE_TEST(negnumber); EXPECT_VFPRINTF("-1234", "%d", -1234); break; + CASE_TEST(unsigned); EXPECT_VFPRINTF("12345", "%u", 12345); break; + CASE_TEST(char); EXPECT_VFPRINTF("c", "%c", 'c'); break; + CASE_TEST(hex); EXPECT_VFPRINTF("f", "%x", 0xf); break; + CASE_TEST(pointer); EXPECT_VFPRINTF("0x1", "%p", (void *) 0x1); break; + CASE_TEST(uintmax_t); EXPECT_VFPRINTF("18446744073709551615", "%ju", 0xffffffffffffffffULL); break; + CASE_TEST(intmax_t); EXPECT_VFPRINTF("-9223372036854775807", "%jd", 0x8000000000000001LL); break; + CASE_TEST(truncation); EXPECT_VFPRINTF("0123456789012345678901234", "%s", "0123456789012345678901234"); break; + CASE_TEST(string_width); EXPECT_VFPRINTF(" 1", "%10s", "1"); break; + CASE_TEST(number_width); EXPECT_VFPRINTF(" 1", "%10d", 1); break; + CASE_TEST(width_trunc); EXPECT_VFPRINTF(" 1", "%25d", 1); break; CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break; CASE_TEST(strerror); EXPECT_ZR(1, test_strerror()); break; CASE_TEST(printf_error); EXPECT_ZR(1, test_printf_error()); break;