1 files changed, 294 insertions, 0 deletions
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
new file mode 100644
index 000000000..fffdaf6ff
--- /dev/null
+++ b/tools/include/nolibc/string.h
@@ -0,0 +1,294 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * string function definitions for NOLIBC
+ * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
+ */
+
+#ifndef _NOLIBC_STRING_H
+#define _NOLIBC_STRING_H
+
+#include "std.h"
+
+static void *malloc(size_t len);
+
+/*
+ * As much as possible, please keep functions alphabetically sorted.
+ */
+
+static __attribute__((unused))
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+	size_t ofs = 0;
+	int c1 = 0;
+
+	while (ofs < n && !(c1 = ((unsigned char *)s1)[ofs] - ((unsigned char *)s2)[ofs])) {
+		ofs++;
+	}
+	return c1;
+}
+
+static __attribute__((unused))
+void *_nolibc_memcpy_up(void *dst, const void *src, size_t len)
+{
+	size_t pos = 0;
+
+	while (pos < len) {
+		((char *)dst)[pos] = ((const char *)src)[pos];
+		pos++;
+	}
+	return dst;
+}
+
+static __attribute__((unused))
+void *_nolibc_memcpy_down(void *dst, const void *src, size_t len)
+{
+	while (len) {
+		len--;
+		((char *)dst)[len] = ((const char *)src)[len];
+	}
+	return dst;
+}
+
+/* might be ignored by the compiler without -ffreestanding, then found as
+ * missing.
+ */
+__attribute__((weak,unused,section(".text.nolibc_memmove")))
+void *memmove(void *dst, const void *src, size_t len)
+{
+	size_t dir, pos;
+
+	pos = len;
+	dir = -1;
+
+	if (dst < src) {
+		pos = -1;
+		dir = 1;
+	}
+
+	while (len) {
+		pos += dir;
+		((char *)dst)[pos] = ((const char *)src)[pos];
+		len--;
+	}
+	return dst;
+}
+
+/* must be exported, as it's used by libgcc on ARM */
+__attribute__((weak,unused,section(".text.nolibc_memcpy")))
+void *memcpy(void *dst, const void *src, size_t len)
+{
+	return _nolibc_memcpy_up(dst, src, len);
+}
+
+/* might be ignored by the compiler without -ffreestanding, then found as
+ * missing.
+ */
+__attribute__((weak,unused,section(".text.nolibc_memset")))
+void *memset(void *dst, int b, size_t len)
+{
+	char *p = dst;
+
+	while (len--) {
+		/* prevent gcc from recognizing memset() here */
+		asm volatile("");
+		*(p++) = b;
+	}
+	return dst;
+}
+
+static __attribute__((unused))
+char *strchr(const char *s, int c)
+{
+	while (*s) {
+		if (*s == (char)c)
+			return (char *)s;
+		s++;
+	}
+	return NULL;
+}
+
+static __attribute__((unused))
+int strcmp(const char *a, const char *b)
+{
+	unsigned int c;
+	int diff;
+
+	while (!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
+		;
+	return diff;
+}
+
+static __attribute__((unused))
+char *strcpy(char *dst, const char *src)
+{
+	char *ret = dst;
+
+	while ((*dst++ = *src++));
+	return ret;
+}
+
+/* this function is only used with arguments that are not constants or when
+ * it's not known because optimizations are disabled. Note that gcc 12
+ * recognizes an strlen() pattern and replaces it with a jump to strlen(),
+ * thus itself, hence the asm() statement below that's meant to disable this
+ * confusing practice.
+ */
+static __attribute__((unused))
+size_t strlen(const char *str)
+{
+	size_t len;
+
+	for (len = 0; str[len]; len++)
+		asm("");
+	return len;
+}
+
+/* do not trust __builtin_constant_p() at -O0, as clang will emit a test and
+ * the two branches, then will rely on an external definition of strlen().
+ */
+#if defined(__OPTIMIZE__)
+#define nolibc_strlen(x) strlen(x)
+#define strlen(str) ({                          \
+	__builtin_constant_p((str)) ?           \
+		__builtin_strlen((str)) :       \
+		nolibc_strlen((str));           \
+})
+#endif
+
+static __attribute__((unused))
+size_t strnlen(const char *str, size_t maxlen)
+{
+	size_t len;
+
+	for (len = 0; (len < maxlen) && str[len]; len++);
+	return len;
+}
+
+static __attribute__((unused))
+char *strdup(const char *str)
+{
+	size_t len;
+	char *ret;
+
+	len = strlen(str);
+	ret = malloc(len + 1);
+	if (__builtin_expect(ret != NULL, 1))
+		memcpy(ret, str, len + 1);
+
+	return ret;
+}
+
+static __attribute__((unused))
+char *strndup(const char *str, size_t maxlen)
+{
+	size_t len;
+	char *ret;
+
+	len = strnlen(str, maxlen);
+	ret = malloc(len + 1);
+	if (__builtin_expect(ret != NULL, 1)) {
+		memcpy(ret, str, len);
+		ret[len] = '\0';
+	}
+
+	return ret;
+}
+
+static __attribute__((unused))
+size_t strlcat(char *dst, const char *src, size_t size)
+{
+	size_t len;
+	char c;
+
+	for (len = 0; dst[len];	len++)
+		;
+
+	for (;;) {
+		c = *src;
+		if (len < size)
+			dst[len] = c;
+		if (!c)
+			break;
+		len++;
+		src++;
+	}
+
+	return len;
+}
+
+static __attribute__((unused))
+size_t strlcpy(char *dst, const char *src, size_t size)
+{
+	size_t len;
+	char c;
+
+	for (len = 0;;) {
+		c = src[len];
+		if (len < size)
+			dst[len] = c;
+		if (!c)
+			break;
+		len++;
+	}
+	return len;
+}
+
+static __attribute__((unused))
+char *strncat(char *dst, const char *src, size_t size)
+{
+	char *orig = dst;
+
+	while (*dst)
+		dst++;
+
+	while (size && (*dst = *src)) {
+		src++;
+		dst++;
+		size--;
+	}
+
+	*dst = 0;
+	return orig;
+}
+
+static __attribute__((unused))
+int strncmp(const char *a, const char *b, size_t size)
+{
+	unsigned int c;
+	int diff = 0;
+
+	while (size-- &&
+	       !(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
+		;
+
+	return diff;
+}
+
+static __attribute__((unused))
+char *strncpy(char *dst, const char *src, size_t size)
+{
+	size_t len;
+
+	for (len = 0; len < size; len++)
+		if ((dst[len] = *src))
+			src++;
+	return dst;
+}
+
+static __attribute__((unused))
+char *strrchr(const char *s, int c)
+{
+	const char *ret = NULL;
+
+	while (*s) {
+		if (*s == (char)c)
+			ret = s;
+		s++;
+	}
+	return (char *)ret;
+}
+
+/* make sure to include all global symbols */
+#include "nolibc.h"
+
+#endif /* _NOLIBC_STRING_H */