Add strtok() and strtok_r() function to libkern.

MFC after:	2 weeks

sys/conf/files

@@ -1413,6 +1413,7 @@ libkern/strncmp.c		standard
 libkern/strncpy.c		standard
 libkern/strsep.c		standard
 libkern/strspn.c		standard
+libkern/strtok.c		standard
 libkern/strtol.c		standard
 libkern/strtoq.c		standard
 libkern/strtoul.c		standard

sys/libkern/strtok.c

@@ -0,0 +1,98 @@
+/*-
+ * Copyright (c) 1998 Softweyr LLC.  All rights reserved.
+ *
+ * strtok_r, from Berkeley strtok
+ * Oct 13, 1998 by Wes Peters <wes@softweyr.com>
+ *
+ * Copyright (c) 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notices, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notices, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by Softweyr LLC, the
+ *      University of California, Berkeley, and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY SOFTWEYR LLC, THE REGENTS AND CONTRIBUTORS
+ * ``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 SOFTWEYR LLC, THE
+ * REGENTS, OR CONTRIBUTORS 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/libkern.h>
+
+char *
+strtok_r(char *s, const char *delim, char **last)
+{
+	const char *spanp;
+	char *tok;
+	int c, sc;
+
+	if (s == NULL && (s = *last) == NULL)
+		return (NULL);
+
+	/*
+	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
+	 */
+cont:
+	c = *s++;
+	for (spanp = delim; (sc = *spanp++) != 0;) {
+		if (c == sc)
+			goto cont;
+	}
+
+	if (c == 0) {		/* no non-delimiter characters */
+		*last = NULL;
+		return (NULL);
+	}
+	tok = s - 1;
+
+	/*
+	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
+	 * Note that delim must have one NUL; we stop if we see that, too.
+	 */
+	for (;;) {
+		c = *s++;
+		spanp = delim;
+		do {
+			if ((sc = *spanp++) == c) {
+				if (c == 0)
+					s = NULL;
+				else
+					s[-1] = '\0';
+				*last = s;
+				return (tok);
+			}
+		} while (sc != 0);
+	}
+	/* NOTREACHED */
+}
+
+char *
+strtok(char *s, const char *delim)
+{
+	static char *last;
+
+	return (strtok_r(s, delim, &last));
+}

sys/sys/libkern.h

@@ -108,6 +108,8 @@ int	 strncmp(const char *, const char *, size_t);
 char	*strncpy(char * __restrict, const char * __restrict, size_t);
 char	*strsep(char **, const char *delim);
 size_t	 strspn(const char *, const char *);
+char	*strtok_r(char *s, const char *delim, char **last);
+char	*strtok(char *s, const char *delim);
 int	 strvalid(const char *, size_t);
 
 extern uint32_t crc32_tab[];