1/*	$OpenBSD: fflush.c,v 1.9 2015/08/31 02:53:57 guenther Exp $ */
2/*-
3 * Copyright (c) 1990, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <errno.h>
35#include <stdio.h>
36#include "local.h"
37
38/* Flush a single file, or (if fp is NULL) all files.  */
39int
40fflush(FILE *fp)
41{
42	int	r;
43
44	if (fp == NULL)
45		return (_fwalk(__sflush_locked));
46	FLOCKFILE(fp);
47	if ((fp->_flags & (__SWR | __SRW)) == 0) {
48		errno = EBADF;
49		r = EOF;
50	} else
51		r = __sflush(fp);
52	FUNLOCKFILE(fp);
53	return (r);
54}
55DEF_STRONG(fflush);
56
57int
58__sflush(FILE *fp)
59{
60	unsigned char *p;
61	int n, t;
62
63	t = fp->_flags;
64	if ((t & __SWR) == 0)
65		return (0);
66
67	if ((p = fp->_bf._base) == NULL)
68		return (0);
69
70	n = fp->_p - p;		/* write this much */
71
72	/*
73	 * Set these immediately to avoid problems with longjmp and to allow
74	 * exchange buffering (via setvbuf) in user write function.
75	 */
76	fp->_p = p;
77	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
78
79	for (; n > 0; n -= t, p += t) {
80		t = (*fp->_write)(fp->_cookie, (char *)p, n);
81		if (t <= 0) {
82			fp->_flags |= __SERR;
83			return (EOF);
84		}
85	}
86	return (0);
87}
88
89int
90__sflush_locked(FILE *fp)
91{
92	int	r;
93
94	FLOCKFILE(fp);
95	r = __sflush(fp);
96	FUNLOCKFILE(fp);
97	return (r);
98}
99