freebsd-skq/lib/libc/stdio/wsetup.c
das 55edbf12e7 Set errno to EBADF on attempts to write to a stream that is not
writable.  Affected callers include fwrite(), put?(), and *printf().
The issue of whether this is the right errno for funopened streams is
unresolved, but that's an obscure case, and some errno is better than
no errno.

Discussed with:	bde, jkh
2004-06-08 05:44:52 +00:00

97 lines
3.2 KiB
C

/*-
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)wsetup.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "local.h"
/*
* Various output routines call wsetup to be sure it is safe to write,
* because either _flags does not include __SWR, or _buf is NULL.
* _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.
*/
int
__swsetup(fp)
FILE *fp;
{
/* make sure stdio is set up */
if (!__sdidinit)
__sinit();
/*
* If we are not writing, we had better be reading and writing.
*/
if ((fp->_flags & __SWR) == 0) {
if ((fp->_flags & __SRW) == 0) {
errno = EBADF;
return (EOF);
}
if (fp->_flags & __SRD) {
/* clobber any ungetc data */
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~(__SRD|__SEOF);
fp->_r = 0;
fp->_p = fp->_bf._base;
}
fp->_flags |= __SWR;
}
/*
* Make a buffer if necessary, then set _w.
*/
if (fp->_bf._base == NULL)
__smakebuf(fp);
if (fp->_flags & __SLBF) {
/*
* It is line buffered, so make _lbfsize be -_bufsize
* for the putc() macro. We will change _lbfsize back
* to 0 whenever we turn off __SWR.
*/
fp->_w = 0;
fp->_lbfsize = -fp->_bf._size;
} else
fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
return (0);
}