diff --git a/libc/stdio/fvwrite.c b/libc/stdio/fvwrite.c
new file mode 100644
index 0000000..bbea672
--- /dev/null
+++ b/libc/stdio/fvwrite.c
@@ -0,0 +1,208 @@
+/*	$OpenBSD: fvwrite.c,v 1.14 2005/08/08 08:05:36 espie 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include "local.h"
+#include "fvwrite.h"
+
+/*
+ * Write some memory regions.  Return zero on success, EOF on error.
+ *
+ * This routine is large and unsightly, but most of the ugliness due
+ * to the three different kinds of output buffering is handled here.
+ */
+int
+__sfvwrite(FILE *fp, struct __suio *uio)
+{
+	size_t len;
+	char *p;
+	struct __siov *iov;
+	int w, s;
+	char *nl;
+	int nlknown, nldist;
+
+	if ((len = uio->uio_resid) == 0)
+		return (0);
+	/* make sure we can write */
+	if (cantwrite(fp)) {
+		errno = EBADF;
+		return (EOF);
+	}
+
+#define	MIN(a, b) ((a) < (b) ? (a) : (b))
+#define	COPY(n)	  (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
+
+	iov = uio->uio_iov;
+	p = iov->iov_base;
+	len = iov->iov_len;
+	iov++;
+#define GETIOV(extra_work) \
+	while (len == 0) { \
+		extra_work; \
+		p = iov->iov_base; \
+		len = iov->iov_len; \
+		iov++; \
+	}
+	if (fp->_flags & __SNBF) {
+		/*
+		 * Unbuffered: write up to BUFSIZ bytes at a time.
+		 */
+		do {
+			GETIOV(;);
+#if 1  /* BIONIC: don't limit to 1KB writes */
+            w = (*fp->_write)(fp->_cookie, p, len);
+#else
+			w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ2));
+#endif
+			if (w <= 0)
+				goto err;
+			p += w;
+			len -= w;
+		} while ((uio->uio_resid -= w) != 0);
+	} else if ((fp->_flags & __SLBF) == 0) {
+		/*
+		 * Fully buffered: fill partially full buffer, if any,
+		 * and then flush.  If there is no partial buffer, write
+		 * one _bf._size byte chunk directly (without copying).
+		 *
+		 * String output is a special case: write as many bytes
+		 * as fit, but pretend we wrote everything.  This makes
+		 * snprintf() return the number of bytes needed, rather
+		 * than the number used, and avoids its write function
+		 * (so that the write function can be invalid).
+		 */
+		do {
+			GETIOV(;);
+			if ((fp->_flags & (__SALC | __SSTR)) ==
+			    (__SALC | __SSTR) && fp->_w < (int)len) {
+				size_t blen = fp->_p - fp->_bf._base;
+				unsigned char *_base;
+				int _size;
+
+				/* Allocate space exponentially. */
+				_size = fp->_bf._size;
+				do {
+					_size = (_size << 1) + 1;
+				} while (_size < (int)(blen + len));
+				_base = realloc(fp->_bf._base, _size + 1);
+				if (_base == NULL)
+					goto err;
+				fp->_w += _size - fp->_bf._size;
+				fp->_bf._base = _base;
+				fp->_bf._size = _size;
+				fp->_p = _base + blen;
+			}
+			w = fp->_w;
+			if (fp->_flags & __SSTR) {
+				if ((int)len < w)
+					w = len;
+				COPY(w);	/* copy MIN(fp->_w,len), */
+				fp->_w -= w;
+				fp->_p += w;
+				w = len;	/* but pretend copied all */
+			} else if (fp->_p > fp->_bf._base && (int)len > w) {
+				/* fill and flush */
+				COPY(w);
+				/* fp->_w -= w; */ /* unneeded */
+				fp->_p += w;
+				if (fflush(fp))
+					goto err;
+			} else if ((int)len >= (w = fp->_bf._size)) {
+				/* write directly */
+				w = (*fp->_write)(fp->_cookie, p, w);
+				if (w <= 0)
+					goto err;
+			} else {
+				/* fill and done */
+				w = len;
+				COPY(w);
+				fp->_w -= w;
+				fp->_p += w;
+			}
+			p += w;
+			len -= w;
+		} while ((uio->uio_resid -= w) != 0);
+	} else {
+		/*
+		 * Line buffered: like fully buffered, but we
+		 * must check for newlines.  Compute the distance
+		 * to the first newline (including the newline),
+		 * or `infinity' if there is none, then pretend
+		 * that the amount to write is MIN(len,nldist).
+		 */
+		nlknown = 0;
+		nldist = 0;	/* XXX just to keep gcc happy */
+		do {
+			GETIOV(nlknown = 0);
+			if (!nlknown) {
+				nl = memchr((void *)p, '\n', len);
+				nldist = nl ? nl + 1 - p : (int)len + 1;
+				nlknown = 1;
+			}
+			s = MIN((int)len, nldist);
+			w = fp->_w + fp->_bf._size;
+			if (fp->_p > fp->_bf._base && s > w) {
+				COPY(w);
+				/* fp->_w -= w; */
+				fp->_p += w;
+				if (fflush(fp))
+					goto err;
+			} else if (s >= (w = fp->_bf._size)) {
+				w = (*fp->_write)(fp->_cookie, p, w);
+				if (w <= 0)
+				 	goto err;
+			} else {
+				w = s;
+				COPY(w);
+				fp->_w -= w;
+				fp->_p += w;
+			}
+			if ((nldist -= w) == 0) {
+				/* copied the newline: flush and forget */
+				if (fflush(fp))
+					goto err;
+				nlknown = 0;
+			}
+			p += w;
+			len -= w;
+		} while ((uio->uio_resid -= w) != 0);
+	}
+	return (0);
+
+err:
+	fp->_flags |= __SERR;
+	return (EOF);
+}