selftests/nolibc: Add tests for strlcat() and strlcpy()

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>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

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 +1010,14 @@ 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()
+		 * Add some more chars after the \0, to test functions that overwrite the buffer set
+		 * the \0 at the exact right position.
+		 */
+		char buf[10] = "test123456";
+		buf[4] = '\0';
+
+
 		/* avoid leaving empty lines below, this will insert holes into
 		 * test numbers.
 		 */
@@ -1007,6 +1034,19 @@ 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, "test"); break;
+		CASE_TEST(strlcat_1);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 1), buf, 4, "test"); break;
+		CASE_TEST(strlcat_5);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 5), buf, 7, "test"); break;
+		CASE_TEST(strlcat_6);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 6), buf, 7, "testb"); break;
+		CASE_TEST(strlcat_7);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 7), buf, 7, "testba"); break;
+		CASE_TEST(strlcat_8);          EXPECT_STRBUFEQ(1, strlcat(buf, "bar", 8), buf, 7, "testbar"); break;
+		CASE_TEST(strlcpy_0);          EXPECT_STRBUFEQ(1, strlcpy(buf, "bar", 0), buf, 3, "test"); 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;