diff --git a/libc/stdio/refill.c b/libc/stdio/refill.c
new file mode 100644
index 0000000..e87c7b9
--- /dev/null
+++ b/libc/stdio/refill.c
@@ -0,0 +1,130 @@
+/*	$OpenBSD: refill.c,v 1.11 2009/11/09 00:18:27 kurt 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 <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "local.h"
+
+static int
+lflush(FILE *fp)
+{
+	if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
+		return (__sflush_locked(fp));	/* ignored... */
+	return (0);
+}
+
+/*
+ * Refill a stdio buffer.
+ * Return EOF on eof or error, 0 otherwise.
+ */
+int
+__srefill(FILE *fp)
+{
+
+	/* make sure stdio is set up */
+	if (!__sdidinit)
+		__sinit();
+
+	fp->_r = 0;		/* largely a convenience for callers */
+
+#if !defined(__ANDROID__)
+	/* SysV does not make this test; take it out for compatibility */
+	if (fp->_flags & __SEOF)
+		return (EOF);
+#endif
+
+	/* if not already reading, have to be reading and writing */
+	if ((fp->_flags & __SRD) == 0) {
+		if ((fp->_flags & __SRW) == 0) {
+			errno = EBADF;
+			fp->_flags |= __SERR;
+			return (EOF);
+		}
+		/* switch to reading */
+		if (fp->_flags & __SWR) {
+			if (__sflush(fp))
+				return (EOF);
+			fp->_flags &= ~__SWR;
+			fp->_w = 0;
+			fp->_lbfsize = 0;
+		}
+		fp->_flags |= __SRD;
+	} else {
+		/*
+		 * We were reading.  If there is an ungetc buffer,
+		 * we must have been reading from that.  Drop it,
+		 * restoring the previous buffer (if any).  If there
+		 * is anything in that buffer, return.
+		 */
+		if (HASUB(fp)) {
+			FREEUB(fp);
+			if ((fp->_r = fp->_ur) != 0) {
+				fp->_p = fp->_up;
+				return (0);
+			}
+		}
+	}
+
+	if (fp->_bf._base == NULL)
+		__smakebuf(fp);
+
+	/*
+	 * Before reading from a line buffered or unbuffered file,
+	 * flush all line buffered output files, per the ANSI C
+	 * standard.
+	 */
+	if (fp->_flags & (__SLBF|__SNBF)) {
+		/* Ignore this file in _fwalk to avoid potential deadlock. */
+		fp->_flags |= __SIGN;
+		(void) _fwalk(lflush);
+		fp->_flags &= ~__SIGN;
+
+		/* Now flush this file without locking it. */
+		if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
+			__sflush(fp);
+	}
+	fp->_p = fp->_bf._base;
+	fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size);
+	fp->_flags &= ~__SMOD;	/* buffer contents are again pristine */
+	if (fp->_r <= 0) {
+		if (fp->_r == 0)
+			fp->_flags |= __SEOF;
+		else {
+			fp->_r = 0;
+			fp->_flags |= __SERR;
+		}
+		return (EOF);
+	}
+	return (0);
+}