tools/nolibc: implement strtol() and friends

The implementation always works on uintmax_t values.

This is inefficient when only 32bit are needed.
However for all functions this only happens for strtol() on 32bit
platforms.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20240425-nolibc-strtol-v1-2-bfeef7846902@weissschuh.net

tools/include/nolibc/stdlib.h

@@ -438,6 +438,115 @@ char *u64toa(uint64_t in)
 	return itoa_buffer;
 }
 
+static __attribute__((unused))
+uintmax_t __strtox(const char *nptr, char **endptr, int base, intmax_t lower_limit, uintmax_t upper_limit)
+{
+	const char signed_ = lower_limit != 0;
+	unsigned char neg = 0, overflow = 0;
+	uintmax_t val = 0, limit, old_val;
+	char c;
+
+	if (base < 0 || base > 36) {
+		SET_ERRNO(EINVAL);
+		goto out;
+	}
+
+	while (isspace(*nptr))
+		nptr++;
+
+	if (*nptr == '+') {
+		nptr++;
+	} else if (*nptr == '-') {
+		neg = 1;
+		nptr++;
+	}
+
+	if (signed_ && neg)
+		limit = -(uintmax_t)lower_limit;
+	else
+		limit = upper_limit;
+
+	if ((base == 0 || base == 16) &&
+	    (strncmp(nptr, "0x", 2) == 0 || strncmp(nptr, "0X", 2) == 0)) {
+		base = 16;
+		nptr += 2;
+	} else if (base == 0 && strncmp(nptr, "0", 1) == 0) {
+		base = 8;
+		nptr += 1;
+	} else if (base == 0) {
+		base = 10;
+	}
+
+	while (*nptr) {
+		c = *nptr;
+
+		if (c >= '0' && c <= '9')
+			c -= '0';
+		else if (c >= 'a' && c <= 'z')
+			c = c - 'a' + 10;
+		else if (c >= 'A' && c <= 'Z')
+			c = c - 'A' + 10;
+		else
+			goto out;
+
+		if (c >= base)
+			goto out;
+
+		nptr++;
+		old_val = val;
+		val *= base;
+		val += c;
+
+		if (val > limit || val < old_val)
+			overflow = 1;
+	}
+
+out:
+	if (overflow) {
+		SET_ERRNO(ERANGE);
+		val = limit;
+	}
+	if (endptr)
+		*endptr = (char *)nptr;
+	return neg ? -val : val;
+}
+
+static __attribute__((unused))
+long strtol(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, LONG_MIN, LONG_MAX);
+}
+
+static __attribute__((unused))
+unsigned long strtoul(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, 0, ULONG_MAX);
+}
+
+static __attribute__((unused))
+long long strtoll(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, LLONG_MIN, LLONG_MAX);
+}
+
+static __attribute__((unused))
+unsigned long long strtoull(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, 0, ULLONG_MAX);
+}
+
+static __attribute__((unused))
+intmax_t strtoimax(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, INTMAX_MIN, INTMAX_MAX);
+}
+
+static __attribute__((unused))
+uintmax_t strtoumax(const char *nptr, char **endptr, int base)
+{
+	return __strtox(nptr, endptr, base, 0, UINTMAX_MAX);
+}
+
 /* make sure to include all global symbols */
 #include "nolibc.h"
 

tools/testing/selftests/nolibc/nolibc-test.c

@@ -621,6 +621,51 @@ int expect_str_buf_eq(size_t expr, const char *buf, size_t val, int llen, const
 	return 0;
 }
 
+#define EXPECT_STRTOX(cond, func, input, base, expected, chars, expected_errno)				\
+	do { if (!(cond)) result(llen, SKIPPED); else ret += expect_strtox(llen, func, input, base, expected, chars, expected_errno); } while (0)
+
+static __attribute__((unused))
+int expect_strtox(int llen, void *func, const char *input, int base, intmax_t expected, int expected_chars, int expected_errno)
+{
+	char *endptr;
+	int actual_errno, actual_chars;
+	intmax_t r;
+
+	errno = 0;
+	if (func == strtol) {
+		r = strtol(input, &endptr, base);
+	} else if (func == strtoul) {
+		r = strtoul(input, &endptr, base);
+	} else {
+		result(llen, FAIL);
+		return 1;
+	}
+	actual_errno = errno;
+	actual_chars = endptr - input;
+
+	llen += printf(" %lld = %lld", (long long)expected, (long long)r);
+	if (r != expected) {
+		result(llen, FAIL);
+		return 1;
+	}
+	if (expected_chars == -1) {
+		if (*endptr != '\0') {
+			result(llen, FAIL);
+			return 1;
+		}
+	} else if (expected_chars != actual_chars) {
+		result(llen, FAIL);
+		return 1;
+	}
+	if (actual_errno != expected_errno) {
+		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) \
 	case __LINE__: llen += printf("%d %s", test, #name);
@@ -1143,6 +1188,22 @@ int run_stdlib(int min, int max)
 		CASE_TEST(limit_ptrdiff_min);       EXPECT_EQ(1, PTRDIFF_MIN, sizeof(long) == 8 ? (ptrdiff_t) 0x8000000000000000LL  : (ptrdiff_t) 0x80000000); break;
 		CASE_TEST(limit_ptrdiff_max);       EXPECT_EQ(1, PTRDIFF_MAX, sizeof(long) == 8 ? (ptrdiff_t) 0x7fffffffffffffffLL  : (ptrdiff_t) 0x7fffffff); break;
 		CASE_TEST(limit_size_max);          EXPECT_EQ(1, SIZE_MAX,    sizeof(long) == 8 ? (size_t)    0xffffffffffffffffULL : (size_t)    0xffffffffU); break;
+		CASE_TEST(strtol_simple);           EXPECT_STRTOX(1, strtol, "35", 10, 35, -1, 0); break;
+		CASE_TEST(strtol_positive);         EXPECT_STRTOX(1, strtol, "+35", 10, 35, -1, 0); break;
+		CASE_TEST(strtol_negative);         EXPECT_STRTOX(1, strtol, "-35", 10, -35, -1, 0); break;
+		CASE_TEST(strtol_hex_auto);         EXPECT_STRTOX(1, strtol, "0xFF", 0, 255, -1, 0); break;
+		CASE_TEST(strtol_base36);           EXPECT_STRTOX(1, strtol, "12yZ", 36, 50507, -1, 0); break;
+		CASE_TEST(strtol_cutoff);           EXPECT_STRTOX(1, strtol, "1234567890", 8, 342391, 7, 0); break;
+		CASE_TEST(strtol_octal_auto);       EXPECT_STRTOX(1, strtol, "011", 0, 9, -1, 0); break;
+		CASE_TEST(strtol_hex_00);           EXPECT_STRTOX(1, strtol, "0x00", 16, 0, -1, 0); break;
+		CASE_TEST(strtol_hex_FF);           EXPECT_STRTOX(1, strtol, "FF", 16, 255, -1, 0); break;
+		CASE_TEST(strtol_hex_ff);           EXPECT_STRTOX(1, strtol, "ff", 16, 255, -1, 0); break;
+		CASE_TEST(strtol_hex_prefix);       EXPECT_STRTOX(1, strtol, "0xFF", 16, 255, -1, 0); break;
+		CASE_TEST(strtol_trailer);          EXPECT_STRTOX(1, strtol, "35foo", 10, 35, 2, 0); break;
+		CASE_TEST(strtol_overflow);         EXPECT_STRTOX(1, strtol, "0x8000000000000000", 16, LONG_MAX, -1, ERANGE); break;
+		CASE_TEST(strtol_underflow);        EXPECT_STRTOX(1, strtol, "-0x8000000000000001", 16, LONG_MIN, -1, ERANGE); break;
+		CASE_TEST(strtoul_negative);        EXPECT_STRTOX(1, strtoul, "-0x1", 16, ULONG_MAX, 4, 0); break;
+		CASE_TEST(strtoul_overflow);        EXPECT_STRTOX(1, strtoul, "0x10000000000000000", 16, ULONG_MAX, -1, ERANGE); break;
 
 		case __LINE__:
 			return ret; /* must be last */