diff --git a/libc/regex/regexec.c b/libc/regex/regexec.c
new file mode 100644
index 0000000..7b3bfc7
--- /dev/null
+++ b/libc/regex/regexec.c
@@ -0,0 +1,160 @@
+/*	$OpenBSD: regexec.c,v 1.11 2005/08/05 13:03:00 espie Exp $ */
+/*-
+ * Copyright (c) 1992, 1993, 1994 Henry Spencer.
+ * Copyright (c) 1992, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Henry Spencer.
+ *
+ * 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. 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 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 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.
+ *
+ *	@(#)regexec.c	8.3 (Berkeley) 3/20/94
+ */
+
+/*
+ * the outer shell of regexec()
+ *
+ * This file includes engine.c *twice*, after muchos fiddling with the
+ * macros that code uses.  This lets the same code operate on two different
+ * representations for state sets.
+ */
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <ctype.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+/* macros for manipulating states, small version */
+#define	states	long
+#define	states1	states		/* for later use in regexec() decision */
+#define	CLEAR(v)	((v) = 0)
+#define	SET0(v, n)	((v) &= ~((unsigned long)1 << (n)))
+#define	SET1(v, n)	((v) |= (unsigned long)1 << (n))
+#define	ISSET(v, n)	(((v) & ((unsigned long)1 << (n))) != 0)
+#define	ASSIGN(d, s)	((d) = (s))
+#define	EQ(a, b)	((a) == (b))
+#define	STATEVARS	long dummy	/* dummy version */
+#define	STATESETUP(m, n)	/* nothing */
+#define	STATETEARDOWN(m)	/* nothing */
+#define	SETUP(v)	((v) = 0)
+#define	onestate	long
+#define	INIT(o, n)	((o) = (unsigned long)1 << (n))
+#define	INC(o)		((o) <<= 1)
+#define	ISSTATEIN(v, o)	(((v) & (o)) != 0)
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define	FWD(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) << (n))
+#define	BACK(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) >> (n))
+#define	ISSETBACK(v, n)		(((v) & ((unsigned long)here >> (n))) != 0)
+/* function names */
+#define SNAMES			/* engine.c looks after details */
+
+#include "engine.c"
+
+/* now undo things */
+#undef	states
+#undef	CLEAR
+#undef	SET0
+#undef	SET1
+#undef	ISSET
+#undef	ASSIGN
+#undef	EQ
+#undef	STATEVARS
+#undef	STATESETUP
+#undef	STATETEARDOWN
+#undef	SETUP
+#undef	onestate
+#undef	INIT
+#undef	INC
+#undef	ISSTATEIN
+#undef	FWD
+#undef	BACK
+#undef	ISSETBACK
+#undef	SNAMES
+
+/* macros for manipulating states, large version */
+#define	states	char *
+#define	CLEAR(v)	memset(v, 0, m->g->nstates)
+#define	SET0(v, n)	((v)[n] = 0)
+#define	SET1(v, n)	((v)[n] = 1)
+#define	ISSET(v, n)	((v)[n])
+#define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
+#define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
+#define	STATEVARS	long vn; char *space
+#define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
+				if ((m)->space == NULL) return(REG_ESPACE); \
+				(m)->vn = 0; }
+#define	STATETEARDOWN(m)	{ free((m)->space); }
+#define	SETUP(v)	((v) = &m->space[m->vn++ * m->g->nstates])
+#define	onestate	long
+#define	INIT(o, n)	((o) = (n))
+#define	INC(o)	((o)++)
+#define	ISSTATEIN(v, o)	((v)[o])
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define	FWD(dst, src, n)	((dst)[here+(n)] |= (src)[here])
+#define	BACK(dst, src, n)	((dst)[here-(n)] |= (src)[here])
+#define	ISSETBACK(v, n)	((v)[here - (n)])
+/* function names */
+#define	LNAMES			/* flag */
+
+#include "engine.c"
+
+/*
+ - regexec - interface for matching
+ *
+ * We put this here so we can exploit knowledge of the state representation
+ * when choosing which matcher to call.  Also, by this point the matchers
+ * have been prototyped.
+ */
+int				/* 0 success, REG_NOMATCH failure */
+regexec(const regex_t *preg, const char *string, size_t nmatch,
+    regmatch_t pmatch[], int eflags)
+{
+	struct re_guts *g = preg->re_g;
+#ifdef REDEBUG
+#	define	GOODFLAGS(f)	(f)
+#else
+#	define	GOODFLAGS(f)	((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
+#endif
+
+	if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
+		return(REG_BADPAT);
+	assert(!(g->iflags&BAD));
+	if (g->iflags&BAD)		/* backstop for no-debug case */
+		return(REG_BADPAT);
+	eflags = GOODFLAGS(eflags);
+
+	if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
+		return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
+	else
+		return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
+}