1/*	$OpenBSD: fflush.c,v 1.8 2009/11/09 00:18:27 kurt 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}
55
56int
57__sflush(FILE *fp)
58{
59	unsigned char *p;
60	int n, t;
61
62	t = fp->_flags;
63	if ((t & __SWR) == 0)
64		return (0);
65
66	if ((p = fp->_bf._base) == NULL)
67		return (0);
68
69	n = fp->_p - p;		/* write this much */
70
71	/*
72	 * Set these immediately to avoid problems with longjmp and to allow
73	 * exchange buffering (via setvbuf) in user write function.
74	 */
75	fp->_p = p;
76	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
77
78	for (; n > 0; n -= t, p += t) {
79		t = (*fp->_write)(fp->_cookie, (char *)p, n);
80		if (t <= 0) {
81			fp->_flags |= __SERR;
82			return (EOF);
83		}
84	}
85	return (0);
86}
87
88int
89__sflush_locked(FILE *fp)
90{
91	int	r;
92
93	FLOCKFILE(fp);
94	r = __sflush(fp);
95	FUNLOCKFILE(fp);
96	return (r);
97}
98