Initial Contribution
diff --git a/libc/stdio/refill.c b/libc/stdio/refill.c
new file mode 100644
index 0000000..74b378e
--- /dev/null
+++ b/libc/stdio/refill.c
@@ -0,0 +1,121 @@
+/* $OpenBSD: refill.c,v 1.8 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 <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(fp));
+ 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 */
+
+ /* SysV does not make this test; take it out for compatibility */
+ if (fp->_flags & __SEOF)
+ return (EOF);
+
+ /* 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))
+ (void) _fwalk(lflush);
+ 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);
+}