diff --git a/libc/stdio/findfp.c b/libc/stdio/findfp.c
new file mode 100644
index 0000000..35d028e
--- /dev/null
+++ b/libc/stdio/findfp.c
@@ -0,0 +1,188 @@
+/*	$OpenBSD: findfp.c,v 1.15 2013/12/17 16:33:27 deraadt Exp $ */
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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.
+ */
+
+#include <sys/param.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "local.h"
+#include "glue.h"
+#include "private/thread_private.h"
+
+#define ALIGNBYTES (sizeof(uintptr_t) - 1)
+#define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES)
+
+int	__sdidinit;
+
+#define	NDYNAMIC 10		/* add ten more whenever necessary */
+
+#define	std(flags, file) \
+	{0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
+	    {(unsigned char *)(__sFext+file), 0},NULL,0,{0},{0},{0},0,0}
+
+				/* the usual - (stdin + stdout + stderr) */
+static FILE usual[FOPEN_MAX - 3];
+static struct __sfileext usualext[FOPEN_MAX - 3];
+static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
+static struct glue *lastglue = &uglue;
+_THREAD_PRIVATE_MUTEX(__sfp_mutex);
+
+struct __sfileext __sFext[3];
+FILE __sF[3] = {
+	std(__SRD, STDIN_FILENO),		/* stdin */
+	std(__SWR, STDOUT_FILENO),		/* stdout */
+	std(__SWR|__SNBF, STDERR_FILENO)	/* stderr */
+};
+struct glue __sglue = { &uglue, 3, __sF };
+
+static struct glue *
+moreglue(int n)
+{
+	struct glue *g;
+	FILE *p;
+	struct __sfileext *pext;
+	static FILE empty;
+	char *data;
+
+	data = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)
+	    + n * sizeof(struct __sfileext));
+	if (data == NULL)
+		return (NULL);
+	g = (struct glue *)data;
+	p = (FILE *)ALIGN(data + sizeof(*g));
+	pext = (struct __sfileext *)
+	    (ALIGN(data + sizeof(*g)) + n * sizeof(FILE));
+	g->next = NULL;
+	g->niobs = n;
+	g->iobs = p;
+	while (--n >= 0) {
+		*p = empty;
+		_FILEEXT_SETUP(p, pext);
+		p++;
+		pext++;
+	}
+	return (g);
+}
+
+/*
+ * Find a free FILE for fopen et al.
+ */
+FILE *
+__sfp(void)
+{
+	FILE *fp;
+	int n;
+	struct glue *g;
+
+	if (!__sdidinit)
+		__sinit();
+
+	_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
+	for (g = &__sglue; g != NULL; g = g->next) {
+		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
+			if (fp->_flags == 0)
+				goto found;
+	}
+
+	/* release lock while mallocing */
+	_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
+	if ((g = moreglue(NDYNAMIC)) == NULL)
+		return (NULL);
+	_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
+	lastglue->next = g;
+	lastglue = g;
+	fp = g->iobs;
+found:
+	fp->_flags = 1;		/* reserve this slot; caller sets real flags */
+	_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
+	fp->_p = NULL;		/* no current pointer */
+	fp->_w = 0;		/* nothing to read or write */
+	fp->_r = 0;
+	fp->_bf._base = NULL;	/* no buffer */
+	fp->_bf._size = 0;
+	fp->_lbfsize = 0;	/* not line buffered */
+	fp->_file = -1;		/* no file */
+/*	fp->_cookie = <any>; */	/* caller sets cookie, _read/_write etc */
+	fp->_lb._base = NULL;	/* no line buffer */
+	fp->_lb._size = 0;
+	_FILEEXT_INIT(fp);
+	return (fp);
+}
+
+/*
+ * exit() and abort() call _cleanup() through the callback registered
+ * with __atexit_register_cleanup(), set whenever we open or buffer a
+ * file. This chicanery is done so that programs that do not use stdio
+ * need not link it all in.
+ *
+ * The name `_cleanup' is, alas, fairly well known outside stdio.
+ */
+void
+_cleanup(void)
+{
+	/* (void) _fwalk(fclose); */
+	(void) _fwalk(__sflush);		/* `cheating' */
+}
+
+/*
+ * __sinit() is called whenever stdio's internal variables must be set up.
+ */
+void
+__sinit(void)
+{
+	_THREAD_PRIVATE_MUTEX(__sinit_mutex);
+
+	_THREAD_PRIVATE_MUTEX_LOCK(__sinit_mutex);
+	if (__sdidinit) {
+		/* bail out if caller lost the race */
+		_THREAD_PRIVATE_MUTEX_UNLOCK(__sinit_mutex);
+		return;
+	}
+
+	/* Initialize stdin/stdout/stderr (for the recursive mutex). http://b/18208568. */
+	for (size_t i = 0; i < 3; ++i) {
+		_FILEEXT_SETUP(__sF+i, __sFext+i);
+	}
+	/* Initialize the pre-allocated (but initially unused) streams. */
+	for (size_t i = 0; i < FOPEN_MAX - 3; ++i) {
+		_FILEEXT_SETUP(usual+i, usualext+i);
+	}
+
+	/* make sure we clean up on exit */
+	__atexit_register_cleanup(_cleanup); /* conservative */
+	__sdidinit = 1;
+
+	_THREAD_PRIVATE_MUTEX_UNLOCK(__sinit_mutex);
+}