Add an implementation of memmem() -- from FreeBSD with some tweaks.

Requires a libc minor bump, committing now so that we have up-to-date
snapshots for the upcoming hackathon.
joint work with millert@
man page bits ok jmc@
input and ok millert@, guenther@, deraadt@

src/include/string.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: string.h,v 1.25 2013/04/11 03:08:47 guenther Exp $	*/
+/*	$OpenBSD: string.h,v 1.26 2013/05/13 10:37:02 ajacoutot Exp $	*/
 /*	$NetBSD: string.h,v 1.6 1994/10/26 00:56:30 cgd Exp $	*/
 
 /*-
@@ -126,6 +126,7 @@ char	*strsignal(int);
 #endif
 
 #if __BSD_VISIBLE
+void	*memmem(const void *, size_t, const void *, size_t);
 void	*memrchr(const void *, int, size_t);
 char	*strcasestr(const char *, const char *);
 size_t	 strlcat(char *, const char *, size_t)

src/lib/libc/string/Makefile.inc

@@ -1,9 +1,9 @@
-#	$OpenBSD: Makefile.inc,v 1.29 2012/08/02 13:38:38 okan Exp $
+#	$OpenBSD: Makefile.inc,v 1.30 2013/05/13 10:37:02 ajacoutot Exp $
 
 # string sources
 .PATH: ${LIBCSRCDIR}/arch/${MACHINE_CPU}/string ${LIBCSRCDIR}/string
 
-SRCS+=	bm.c memccpy.c memrchr.c stpcpy.c stpncpy.c \
+SRCS+=	bm.c memccpy.c memmem.c memrchr.c stpcpy.c stpncpy.c \
 	strcasecmp.c strcasestr.c strcoll.c strdup.c \
 	strerror.c strerror_r.c strlcat.c strmode.c strndup.c strnlen.c \
 	strsignal.c strtok.c strxfrm.c \
@@ -121,8 +121,8 @@ strrchr.so: rindex.c
 .endif
 
 MAN+=	bm.3 bcmp.3 bcopy.3 bstring.3 bzero.3 ffs.3 memccpy.3 memchr.3 \
-	memcmp.3 memcpy.3 memmove.3 memset.3 stpcpy.3 strcasecmp.3 strcat.3 \
-	strchr.3 strcmp.3 strcoll.3 strcpy.3 strcspn.3 strerror.3 \
+	memcmp.3 memcpy.3 memmem.3 memmove.3 memset.3 stpcpy.3 strcasecmp.3 \
+	strcat.3 strchr.3 strcmp.3 strcoll.3 strcpy.3 strcspn.3 strerror.3 \
 	string.3 strlen.3 strmode.3 strdup.3 strpbrk.3 strrchr.3 strsep.3 \
 	strsignal.3 strspn.3 strstr.3 strtok.3 strxfrm.3 swab.3 strlcpy.3 \
 	wcscasecmp.3 wcscat.3 wcschr.3 wcscmp.3 wcscpy.3 wcscspn.3 wcsdup.3 \

src/lib/libc/string/memmem.3

@@ -0,0 +1,77 @@
+.\"	$OpenBSD: memmem.3,v 1.1 2013/05/13 10:37:02 ajacoutot Exp $
+.\"
+.\" Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
+.\"
+.\" 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
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. 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.
+.\" 3. The name of the author may not be used to endorse or promote
+.\"    products derived from this software without specific prior written
+.\"    permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR 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.
+.\"
+.Dd $Mdocdate: May 13 2013 $
+.Dt MEMMEM 3
+.Os
+.Sh NAME
+.Nm memmem
+.Nd locate a byte substring in a byte string
+.Sh SYNOPSIS
+.In string.h
+.Ft "void *"
+.Fo memmem
+.Fa "const void *big" "size_t big_len"
+.Fa "const void *little" "size_t little_len"
+.Fc
+.Sh DESCRIPTION
+The
+.Fn memmem
+function
+locates the first occurrence of the byte string
+.Fa little
+in the byte string
+.Fa big .
+.Sh RETURN VALUES
+If
+.Fa little
+is zero length,
+.Fa big
+is returned; if
+.Fa little
+occurs nowhere in
+.Fa big ,
+.Dv NULL
+is returned;
+otherwise a pointer to the first character of the first occurrence of
+.Fa little
+is returned.
+.Sh SEE ALSO
+.Xr memchr 3 ,
+.Xr strchr 3 ,
+.Xr strstr 3
+.Sh STANDARDS
+.Fn memmem
+is a GNU extension.
+.Sh HISTORY
+The
+.Fn memmem
+function first appeared in
+.Ox 5.4 .
+.Sh AUTHORS
+.An Pascal Gloor Aq pascal.gloor@spale.com

src/lib/libc/string/memmem.c

@@ -0,0 +1,64 @@
+/*	$OpenBSD: memmem.c,v 1.1 2013/05/13 10:37:02 ajacoutot Exp $ */
+/*-
+ * Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
+ *
+ * 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
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR 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>
+#include <string.h>
+
+/*
+ * Find the first occurrence of the byte string s in byte string l.
+ */
+
+void *
+memmem(const void *l, size_t l_len, const void *s, size_t s_len)
+{
+	const char *cur, *last;
+	const char *cl = l;
+	const char *cs = s;
+
+	/* a zero length needle should just return the haystack */
+	if (l_len == 0)
+		return (void *)cl;
+
+	/* "s" must be smaller or equal to "l" */
+	if (l_len < s_len)
+		return NULL;
+
+	/* special case where s_len == 1 */
+	if (s_len == 1)
+		return memchr(l, *cs, l_len);
+
+	/* the last position where its possible to find "s" in "l" */
+	last = cl + l_len - s_len;
+
+	for (cur = cl; cur <= last; cur++)
+		if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
+			return (void *)cur;
+
+	return NULL;
+}