xref: /freebsd/lib/libc/stdio/fflush.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";
40 #endif
41 static const char rcsid[] =
42   "$FreeBSD$";
43 #endif /* LIBC_SCCS and not lint */
44 
45 #include "namespace.h"
46 #include <errno.h>
47 #include <stdio.h>
48 #include "un-namespace.h"
49 #include "libc_private.h"
50 #include "local.h"
51 
52 static int	sflush_locked(FILE *);
53 
54 /*
55  * Flush a single file, or (if fp is NULL) all files.
56  * MT-safe version
57  */
58 int
59 fflush(FILE *fp)
60 {
61 	int retval;
62 
63 	if (fp == NULL)
64 		return (_fwalk(sflush_locked));
65 	FLOCKFILE(fp);
66 	if ((fp->_flags & (__SWR | __SRW)) == 0) {
67 		errno = EBADF;
68 		retval = EOF;
69 	} else
70 		retval = __sflush(fp);
71 	FUNLOCKFILE(fp);
72 	return (retval);
73 }
74 
75 /*
76  * Flush a single file, or (if fp is NULL) all files.
77  * Non-MT-safe version
78  */
79 int
80 __fflush(FILE *fp)
81 {
82 	int retval;
83 
84 	if (fp == NULL)
85 		return (_fwalk(sflush_locked));
86 	if ((fp->_flags & (__SWR | __SRW)) == 0) {
87 		errno = EBADF;
88 		retval = EOF;
89 	} else
90 		retval = __sflush(fp);
91 	return (retval);
92 }
93 
94 int
95 __sflush(FILE *fp)
96 {
97 	unsigned char *p;
98 	int n, t;
99 
100 	t = fp->_flags;
101 	if ((t & __SWR) == 0)
102 		return (0);
103 
104 	if ((p = fp->_bf._base) == NULL)
105 		return (0);
106 
107 	n = fp->_p - p;		/* write this much */
108 
109 	/*
110 	 * Set these immediately to avoid problems with longjmp and to allow
111 	 * exchange buffering (via setvbuf) in user write function.
112 	 */
113 	fp->_p = p;
114 	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
115 
116 	for (; n > 0; n -= t, p += t) {
117 		t = (*fp->_write)(fp->_cookie, (char *)p, n);
118 		if (t <= 0) {
119 			fp->_flags |= __SERR;
120 			return (EOF);
121 		}
122 	}
123 	return (0);
124 }
125 
126 static int
127 sflush_locked(FILE *fp)
128 {
129 	int	ret;
130 
131 	FLOCKFILE(fp);
132 	ret = __sflush(fp);
133 	FUNLOCKFILE(fp);
134 	return (ret);
135 }
136