feat: add given files

Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>

libs/libc/Makefile

@@ -0,0 +1,57 @@
+#
+# Copyright (c) LSE
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in the
+#       documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY LSE AS IS AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL LSE BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+include ../../config.mk
+
+LIB	= libc.a
+OBJS	= \
+	  memchr.o \
+	  memcmp.o \
+	  memcpy.o \
+	  memmove.o \
+	  memset.o \
+	  printf.o \
+	  puts.o \
+	  strcasecmp.o \
+	  strcat.o \
+	  strcmp.o \
+	  strcpy.o \
+	  strlen.o \
+	  strncasecmp.o \
+	  strncmp.o \
+	  strncpy.o \
+	  strnlen.o \
+
+DEPS = $(OBJS:.o=.d)
+
+$(OBJS): CPPFLAGS += -MMD -Iinclude -I../../k/include/
+
+all: $(LIB)
+
+$(LIB): $(OBJS)
+	$(AR) $(ARFLAGS) $@ $^
+
+clean:
+	$(RM) $(OBJS) $(DEPS) $(LIB)
+
+-include $(DEPS)

libs/libc/include/assert.h

@@ -0,0 +1,47 @@
+/*
+* Copyright (c) LSE
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*
+* THIS SOFTWARE IS PROVIDED BY LSE AS IS AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL LSE BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#ifndef ASSERT_H
+#define ASSERT_H
+
+#include <stdio.h>
+
+#ifndef NDEBUG
+#define assert(exp)							\
+     do									\
+     {									\
+       if (!(exp))							\
+       {								\
+         printf("%s, %d: assertion '%s' failed\n",			\
+		__BASE_FILE__, __LINE__, exp);				\
+         printf("System halted.\n");					\
+         while (1)							\
+	   continue;							\
+       }								\
+     }									\
+     while (0)
+#else
+#define assert(exp) ((void) 0)
+#endif
+
+#endif				/* !ASSERT_H */

libs/libc/include/ctype.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) LSE
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY LSE AS IS AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL LSE BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef CTYPE_H_
+#define CTYPE_H_
+
+static inline int tolower(int c)
+{
+	if (c >= 'A' && c <= 'Z')
+		return c + ('a' - 'A');
+	return c;
+}
+
+static inline int toupper(int c)
+{
+	if (c >= 'a' && c <= 'z')
+		return c - ('a' - 'A');
+	return c;
+}
+
+#endif				/* !CTYPE_H_ */

libs/libc/include/limits.h

@@ -0,0 +1,27 @@
+#ifndef LIMITS_H_
+#define LIMITS_H_
+
+#if '\0'-1 > 0
+#define CHAR_MIN 0
+#define CHAR_MAX 255
+#else
+#define CHAR_MIN (-128)
+#define CHAR_MAX 127
+#endif
+
+#define CHAR_BIT 8
+#define SCHAR_MIN (-128)
+#define SCHAR_MAX 127
+#define UCHAR_MAX 255
+#define SHRT_MIN  (-1-0x7fff)
+#define SHRT_MAX  0x7fff
+#define USHRT_MAX 0xffff
+#define INT_MIN  (-1-0x7fffffff)
+#define INT_MAX  0x7fffffff
+#define UINT_MAX 0xffffffffU
+#define LONG_MIN (-LONG_MAX-1)
+#define ULONG_MAX (2UL*LONG_MAX+1)
+#define LLONG_MIN (-LLONG_MAX-1)
+#define ULLONG_MAX (2ULL*LLONG_MAX+1)
+
+#endif /* !LIMITS_H_ */

libs/libc/include/stdio.h

@@ -0,0 +1,34 @@
+/*
+* Copyright (c) LSE
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*
+* THIS SOFTWARE IS PROVIDED BY LSE AS IS AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL LSE BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#ifndef STDIO_H_
+#define STDIO_H_
+
+#include <stdarg.h>
+
+int puts(const char *s);
+int printf(const char *format, ...);
+int sprintf(char *buf, const char *format, ...);
+int vsprintf(char *buf, const char *format, va_list args);
+
+#endif				/* !STDLIB_H_ */

libs/libc/include/string.h

@@ -0,0 +1,45 @@
+/*
+* Copyright (c) LSE
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*
+* THIS SOFTWARE IS PROVIDED BY LSE AS IS AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL LSE BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#ifndef STRING_H_
+#define STRING_H_
+
+#include <stddef.h>
+
+void *memchr(const void *s, int c, size_t n);
+int memcmp(const void *s1, const void *s2, size_t n);
+void *memcpy(void *dest, const void *src, size_t n);
+void *memmove(void *dest, const void *src, size_t n);
+void *memset(void *s, int c, size_t n);
+int strcasecmp(const char *s1, const char *s2);
+int strncasecmp(const char *s1, const char *s2, size_t n);
+char *strcat(char *dest, const char *src);
+int strcmp(const char *s1, const char *s2);
+char *strcpy(char *dest, const char *src);
+char *strdup(const char *s);
+size_t strlen(const char *s);
+size_t strnlen(const char *s, size_t maxlen);
+int strncmp(const char *s1, const char *s2, size_t n);
+char *strncpy(char *dest, const char *src, size_t n);
+
+#endif				/* !STRING_H_ */

libs/libc/memchr.c

@@ -0,0 +1,12 @@
+#include <stddef.h>
+
+void *memchr(const void *s, int c, size_t n)
+{
+	const char *data = s;
+
+	while (n--)
+		if (*data++ == (char)c)
+			return (void *)(data - 1);
+
+	return NULL;
+}

libs/libc/memcmp.c

@@ -0,0 +1,13 @@
+#include <string.h>
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+	const char *d1 = s1;
+	const char *d2 = s2;
+
+	for (size_t i = 0; i < n; ++i)
+		if (d1[i] != d2[i])
+			return d1[i] - d2[i];
+
+	return 0;
+}

libs/libc/memcpy.c

@@ -0,0 +1,12 @@
+#include <string.h>
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	const char *s = src;
+	char *d = dest;
+
+	for (size_t i = 0; i < n; i++)
+		*d++ = *s++;
+
+	return dest;
+}

libs/libc/memmove.c

@@ -0,0 +1,16 @@
+#include <stddef.h>
+#include <string.h>
+
+void *memmove(void *dest, const void *src, size_t n)
+{
+	char *d = dest;
+	const char *s = src;
+
+	if (s < d && s + n > d) {
+		while (n-- > 0)
+			d[n - 1] = s[n - 1];
+		return dest;
+	}
+
+	return memcpy(dest, src, n);
+}

libs/libc/memset.c

@@ -0,0 +1,11 @@
+#include <string.h>
+
+void *memset(void *s, int c, size_t n)
+{
+	char *p = s;
+
+	for (size_t i = 0; i < n; ++i)
+		p[i] = c;
+
+	return s;
+}

libs/libc/printf.c

@@ -0,0 +1,318 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Oh, it's a waste of space, but oh-so-yummy for debugging.  This
+ * version of printf() does not include 64-bit support.  "Live with
+ * it."
+ *
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+static inline int isdigit(int c)
+{
+	return c >= '0' && c <= '9';
+}
+
+static int skip_atoi(const char **s)
+{
+	int i = 0;
+
+	while (isdigit(**s))
+		i = i * 10 + *((*s)++) - '0';
+	return i;
+}
+
+#define ZEROPAD	1		/* pad with zero */
+#define SIGN	2		/* unsigned/signed long */
+#define PLUS	4		/* show plus */
+#define SPACE	8		/* space if plus */
+#define LEFT	16		/* left justified */
+#define SMALL	32		/* Must be 32 == 0x20 */
+#define SPECIAL	64		/* 0x */
+
+#define __do_div(n, base) ({ \
+int __res; \
+__res = ((unsigned long) n) % (unsigned) base; \
+n = ((unsigned long) n) / (unsigned) base; \
+__res; })
+
+static char *number(char *str, long num, int base, int size, int precision,
+		    int type)
+{
+	/* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
+	static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
+
+	char tmp[66];
+	char c, sign, locase;
+	int i;
+
+	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
+	 * produces same digits or (maybe lowercased) letters */
+	locase = (type & SMALL);
+	if (type & LEFT)
+		type &= ~ZEROPAD;
+	if (base < 2 || base > 16)
+		return NULL;
+	c = (type & ZEROPAD) ? '0' : ' ';
+	sign = 0;
+	if (type & SIGN) {
+		if (num < 0) {
+			sign = '-';
+			num = -num;
+			size--;
+		} else if (type & PLUS) {
+			sign = '+';
+			size--;
+		} else if (type & SPACE) {
+			sign = ' ';
+			size--;
+		}
+	}
+	if (type & SPECIAL) {
+		if (base == 16)
+			size -= 2;
+		else if (base == 8)
+			size--;
+	}
+	i = 0;
+	if (num == 0)
+		tmp[i++] = '0';
+	else
+		while (num != 0)
+			tmp[i++] = (digits[__do_div(num, base)] | locase);
+	if (i > precision)
+		precision = i;
+	size -= precision;
+	if (!(type & (ZEROPAD + LEFT)))
+		while (size-- > 0)
+			*str++ = ' ';
+	if (sign)
+		*str++ = sign;
+	if (type & SPECIAL) {
+		if (base == 8)
+			*str++ = '0';
+		else if (base == 16) {
+			*str++ = '0';
+			*str++ = ('X' | locase);
+		}
+	}
+	if (!(type & LEFT))
+		while (size-- > 0)
+			*str++ = c;
+	while (i < precision--)
+		*str++ = '0';
+	while (i-- > 0)
+		*str++ = tmp[i];
+	while (size-- > 0)
+		*str++ = ' ';
+	return str;
+}
+
+int vsprintf(char *buf, const char *fmt, va_list args)
+{
+	int len;
+	unsigned long num;
+	int i, base;
+	char *str;
+	const char *s;
+
+	int flags;		/* flags to number() */
+
+	int field_width;	/* width of output field */
+	int precision;		/* min. # of digits for integers; max
+				   number of chars for from string */
+	int qualifier;		/* 'h', 'l', or 'L' for integer fields */
+
+	for (str = buf; *fmt; ++fmt) {
+		if (*fmt != '%') {
+			*str++ = *fmt;
+			continue;
+		}
+
+		/* process flags */
+		flags = 0;
+	      repeat:
+		++fmt;		/* this also skips first '%' */
+		switch (*fmt) {
+		case '-':
+			flags |= LEFT;
+			goto repeat;
+		case '+':
+			flags |= PLUS;
+			goto repeat;
+		case ' ':
+			flags |= SPACE;
+			goto repeat;
+		case '#':
+			flags |= SPECIAL;
+			goto repeat;
+		case '0':
+			flags |= ZEROPAD;
+			goto repeat;
+		}
+
+		/* get field width */
+		field_width = -1;
+		if (isdigit(*fmt))
+			field_width = skip_atoi(&fmt);
+		else if (*fmt == '*') {
+			++fmt;
+			/* it's the next argument */
+			field_width = va_arg(args, int);
+			if (field_width < 0) {
+				field_width = -field_width;
+				flags |= LEFT;
+			}
+		}
+
+		/* get the precision */
+		precision = -1;
+		if (*fmt == '.') {
+			++fmt;
+			if (isdigit(*fmt))
+				precision = skip_atoi(&fmt);
+			else if (*fmt == '*') {
+				++fmt;
+				/* it's the next argument */
+				precision = va_arg(args, int);
+			}
+			if (precision < 0)
+				precision = 0;
+		}
+
+		/* get the conversion qualifier */
+		qualifier = -1;
+		if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
+			qualifier = *fmt;
+			++fmt;
+		}
+
+		/* default base */
+		base = 10;
+
+		switch (*fmt) {
+		case 'c':
+			if (!(flags & LEFT))
+				while (--field_width > 0)
+					*str++ = ' ';
+			*str++ = (unsigned char)va_arg(args, int);
+			while (--field_width > 0)
+				*str++ = ' ';
+			continue;
+
+		case 's':
+			s = va_arg(args, char *);
+			len = strnlen(s, precision);
+
+			if (!(flags & LEFT))
+				while (len < field_width--)
+					*str++ = ' ';
+			for (i = 0; i < len; ++i)
+				*str++ = *s++;
+			while (len < field_width--)
+				*str++ = ' ';
+			continue;
+
+		case 'p':
+			if (field_width == -1) {
+				field_width = 2 * sizeof(void *);
+				flags |= ZEROPAD;
+			}
+			str = number(str,
+				     (unsigned long)va_arg(args, void *), 16,
+				     field_width, precision, flags);
+			continue;
+
+		case 'n':
+			if (qualifier == 'l') {
+				long *ip = va_arg(args, long *);
+				*ip = (str - buf);
+			} else {
+				int *ip = va_arg(args, int *);
+				*ip = (str - buf);
+			}
+			continue;
+
+		case '%':
+			*str++ = '%';
+			continue;
+
+			/* integer number formats - set up the flags and "break" */
+		case 'o':
+			base = 8;
+			break;
+
+		case 'x':
+			flags |= SMALL;
+			/* Falls through. */
+		case 'X':
+			base = 16;
+			break;
+
+		case 'd':
+		case 'i':
+			flags |= SIGN;
+		case 'u':
+			break;
+
+		default:
+			*str++ = '%';
+			if (*fmt)
+				*str++ = *fmt;
+			else
+				--fmt;
+			continue;
+		}
+		if (qualifier == 'l')
+			num = va_arg(args, unsigned long);
+		else if (qualifier == 'h') {
+			num = (unsigned short)va_arg(args, int);
+			if (flags & SIGN)
+				num = (short)num;
+		} else if (flags & SIGN)
+			num = va_arg(args, int);
+		else
+			num = va_arg(args, unsigned int);
+		str = number(str, num, base, field_width, precision, flags);
+	}
+	*str = '\0';
+	return str - buf;
+}
+
+int sprintf(char *buf, const char *fmt, ...)
+{
+	va_list args;
+	int i;
+
+	va_start(args, fmt);
+	i = vsprintf(buf, fmt, args);
+	va_end(args);
+	return i;
+}
+
+int printf(const char *fmt, ...)
+{
+	char printf_buf[1024];
+	va_list args;
+	int printed;
+
+	va_start(args, fmt);
+	printed = vsprintf(printf_buf, fmt, args);
+	va_end(args);
+
+	puts(printf_buf);
+
+	return printed;
+}

libs/libc/puts.c

@@ -0,0 +1,8 @@
+#include <string.h>
+
+int write(const char *s, size_t nb);
+
+int puts(const char *s)
+{
+	return write(s, strlen(s));
+}

libs/libc/strcasecmp.c

@@ -0,0 +1,10 @@
+#include <ctype.h>
+
+int strcasecmp(const char *s1, const char *s2)
+{
+	for (; *s1; s1++, s2++)
+		if (tolower(*s1) != tolower(*s2))
+			break;
+
+	return tolower(*s1) - tolower(*s2);
+}

libs/libc/strcat.c

@@ -0,0 +1,6 @@
+#include <string.h>
+
+char *strcat(char *dest, const char *src)
+{
+	return strcpy(dest + strlen(dest), src);
+}

libs/libc/strcmp.c

@@ -0,0 +1,10 @@
+#include <string.h>
+
+int strcmp(const char *s1, const char *s2)
+{
+	for (; *s1 == *s2 && *s1 != '\0'; s1++, s2++)
+		continue;
+
+	return *s1 - *s2;
+}
+

libs/libc/strcpy.c

@@ -0,0 +1,13 @@
+#include <string.h>
+
+char *strcpy(char *dest, const char *src)
+{
+	char *p = dest;
+
+	while (*src)
+		*p++ = *src++;
+
+	*p = '\0';
+
+	return dest;
+}

libs/libc/strlen.c

@@ -0,0 +1,12 @@
+#include <string.h>
+#include <stddef.h>
+
+size_t strlen(const char *s)
+{
+	const char *p = s;
+
+	while (*p)
+		p++;
+
+	return (p - s);
+}

libs/libc/strncasecmp.c

@@ -0,0 +1,11 @@
+#include <stddef.h>
+#include <ctype.h>
+
+int strncasecmp(const char *s1, const char *s2, size_t n)
+{
+	for (; *s1 && n > 0; s1++, s2++, n--)
+		if (tolower(*s1) != tolower(*s2))
+			break;
+
+	return n ? tolower(*s1) - tolower(*s2) : 0;
+}

libs/libc/strncmp.c

@@ -0,0 +1,9 @@
+#include <string.h>
+
+int strncmp(const char *s1, const char *s2, size_t n)
+{
+	for (; *s1 == *s2 && *s1 != '\0' && n > 0; s1++, s2++, n--)
+		continue;
+
+	return n ? *s1 - *s2 : 0;
+}

libs/libc/strncpy.c

@@ -0,0 +1,13 @@
+#include <string.h>
+#include <stddef.h>
+
+char *strncpy(char *dest, const char *src, size_t n)
+{
+	size_t i;
+
+	for (i = 0; i < n && src[i] != '\0'; ++i)
+		dest[i] = src[i];
+	memset(dest + i, '\0', n - i);
+
+	return dest;
+}

libs/libc/strnlen.c

@@ -0,0 +1,10 @@
+#include <string.h>
+
+size_t strnlen(const char *s, size_t maxlen)
+{
+	size_t i = 0;
+	for (; i < maxlen; ++i)
+		if (!s[i])
+			return i;
+	return i;
+}