I've verified that the tests matches libbsd's strlcat()/strlcpy()
implementation.

Please note that as strlcat()/strlcpy() are not part of the libc, the
tests are only compiled when using nolibc.

Signed-off-by: Rodrigo Campos <rodrigo@sdfg.com.ar>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 34 ++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 6ba4f8275ac4..aa365443bb2b 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -600,6 +600,25 @@ int expect_strne(const char *expr, int llen, const char *cmp)
 	return ret;
 }
 
+#define EXPECT_STRBUFEQ(cond, expr, buf, val, cmp)				\
+	do { if (!(cond)) result(llen, SKIPPED); else ret += expect_str_buf_eq(expr, buf, val, llen, cmp); } while (0)
+
+static __attribute__((unused))
+int expect_str_buf_eq(size_t expr, const char *buf, size_t val, int llen, const char *cmp)
+{
+	llen += printf(" = %lu <%s> ", expr, buf);
+	if (strcmp(buf, cmp) != 0) {
+		result(llen, FAIL);
+		return 1;
+	}
+	if (expr != val) {
+		result(llen, FAIL);
+		return 1;
+	}
+
+	result(llen, OK);
+	return 0;
+}
 
 /* declare tests based on line numbers. There must be exactly one test per line. */
 #define CASE_TEST(name) \
@@ -991,6 +1010,9 @@ int run_stdlib(int min, int max)
 	for (test = min; test >= 0 && test <= max; test++) {
 		int llen = 0; /* line length */
 
+		/* For functions that take a long buffer, like strlcat() */
+		char buf[7] = "foo";
+
 		/* avoid leaving empty lines below, this will insert holes into
 		 * test numbers.
 		 */
@@ -1007,6 +1029,18 @@ int run_stdlib(int min, int max)
 		CASE_TEST(strchr_foobar_z);    EXPECT_STRZR(1, strchr("foobar", 'z')); break;
 		CASE_TEST(strrchr_foobar_o);   EXPECT_STREQ(1, strrchr("foobar", 'o'), "obar"); break;
 		CASE_TEST(strrchr_foobar_z);   EXPECT_STRZR(1, strrchr("foobar", 'z')); break;
+#ifdef NOLIBC
+		CASE_TEST(strlcat_0);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 0), buf, 3, "foo"); break;
+		CASE_TEST(strlcat_1);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 1), buf, 4, "foo"); break;
+		CASE_TEST(strlcat_3);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 3), buf, 6, "foo"); break;
+		CASE_TEST(strlcat_5);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 5), buf, 6, "foob"); break;
+		CASE_TEST(strlcat_7);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 7), buf, 6, "foobar"); break;
+		CASE_TEST(strlcpy_0);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 0), buf, 3, "foo"); break;
+		CASE_TEST(strlcpy_1);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 1), buf, 3, ""); break;
+		CASE_TEST(strlcpy_2);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 2), buf, 3, "b"); break;
+		CASE_TEST(strlcpy_3);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 3), buf, 3, "ba"); break;
+		CASE_TEST(strlcpy_4);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 4), buf, 3, "bar"); break;
+#endif
 		CASE_TEST(memcmp_20_20);       EXPECT_EQ(1, memcmp("aaa\x20", "aaa\x20", 4), 0); break;
 		CASE_TEST(memcmp_20_60);       EXPECT_LT(1, memcmp("aaa\x20", "aaa\x60", 4), 0); break;
 		CASE_TEST(memcmp_60_20);       EXPECT_GT(1, memcmp("aaa\x60", "aaa\x20", 4), 0); break;
-- 
2.43.0

On 1/29/24 15:15, Rodrigo Campos wrote:
> +		/* For functions that take a long buffer, like strlcat() */
> +		char buf[7] = "foo";
> +

I've improved this to not be the same length as the other buffer (we 
can't catch mistakes like confusing the src and dst buffers like that) 
and added some trailing chars, so we also test that the \0 is added at 
the exactly right position.

On Mon, Jan 29, 2024 at 03:15:16PM +0100, Rodrigo Campos wrote:
> I've verified that the tests matches libbsd's strlcat()/strlcpy()
> implementation.
> 
> Please note that as strlcat()/strlcpy() are not part of the libc, the
> tests are only compiled when using nolibc.
> 
> Signed-off-by: Rodrigo Campos <rodrigo@sdfg.com.ar>

I like it, simple and efficient, thank you!
Willy