wsetup.c revision 130230 
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)
38static char sccsid[] = "@(#)wsetup.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: head/lib/libc/stdio/wsetup.c 130230 2004-06-08 05:44:52Z das $");
42
43#include <errno.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include "local.h"
47
48/*
49 * Various output routines call wsetup to be sure it is safe to write,
50 * because either _flags does not include __SWR, or _buf is NULL.
51 * _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.
52 */
53int
54__swsetup(fp)
55	FILE *fp;
56{
57	/* make sure stdio is set up */
58	if (!__sdidinit)
59		__sinit();
60
61	/*
62	 * If we are not writing, we had better be reading and writing.
63	 */
64	if ((fp->_flags & __SWR) == 0) {
65		if ((fp->_flags & __SRW) == 0) {
66			errno = EBADF;
67			return (EOF);
68		}
69		if (fp->_flags & __SRD) {
70			/* clobber any ungetc data */
71			if (HASUB(fp))
72				FREEUB(fp);
73			fp->_flags &= ~(__SRD|__SEOF);
74			fp->_r = 0;
75			fp->_p = fp->_bf._base;
76		}
77		fp->_flags |= __SWR;
78	}
79
80	/*
81	 * Make a buffer if necessary, then set _w.
82	 */
83	if (fp->_bf._base == NULL)
84		__smakebuf(fp);
85	if (fp->_flags & __SLBF) {
86		/*
87		 * It is line buffered, so make _lbfsize be -_bufsize
88		 * for the putc() macro.  We will change _lbfsize back
89		 * to 0 whenever we turn off __SWR.
90		 */
91		fp->_w = 0;
92		fp->_lbfsize = -fp->_bf._size;
93	} else
94		fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
95	return (0);
96}
97