freebsd-dev/lib/libc/stdio/fflush.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

153 lines
4.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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[] = "@(#)fflush.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <errno.h>
#include <stdio.h>
#include "un-namespace.h"
#include "libc_private.h"
#include "local.h"
static int sflush_locked(FILE *);
/*
* Flush a single file, or (if fp is NULL) all files.
* MT-safe version
*/
int
fflush(FILE *fp)
{
int retval;
if (fp == NULL)
return (_fwalk(sflush_locked));
FLOCKFILE_CANCELSAFE(fp);
/*
* There is disagreement about the correct behaviour of fflush()
* when passed a file which is not open for writing. According to
* the ISO C standard, the behaviour is undefined.
* Under linux, such an fflush returns success and has no effect;
* under Windows, such an fflush is documented as behaving instead
* as fpurge().
* Given that applications may be written with the expectation of
* either of these two behaviours, the only safe (non-astonishing)
* option is to return EBADF and ask that applications be fixed.
* SUSv3 now requires that fflush() returns success on a read-only
* stream.
*
*/
if ((fp->_flags & (__SWR | __SRW)) == 0)
retval = 0;
else
retval = __sflush(fp);
FUNLOCKFILE_CANCELSAFE();
return (retval);
}
/*
* Flush a single file, or (if fp is NULL) all files.
* Non-MT-safe version
*/
int
__fflush(FILE *fp)
{
int retval;
if (fp == NULL)
return (_fwalk(sflush_locked));
if ((fp->_flags & (__SWR | __SRW)) == 0)
retval = 0;
else
retval = __sflush(fp);
return (retval);
}
int
__sflush(FILE *fp)
{
unsigned char *p;
int n, t;
t = fp->_flags;
if ((t & __SWR) == 0)
return (0);
if ((p = fp->_bf._base) == NULL)
return (0);
n = fp->_p - p; /* write this much */
/*
* Set these immediately to avoid problems with longjmp and to allow
* exchange buffering (via setvbuf) in user write function.
*/
fp->_p = p;
fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
for (; n > 0; n -= t, p += t) {
t = _swrite(fp, (char *)p, n);
if (t <= 0) {
/* Reset _p and _w. */
if (p > fp->_p) {
/* Some was written. */
memmove(fp->_p, p, n);
fp->_p += n;
if ((fp->_flags & (__SLBF | __SNBF)) == 0)
fp->_w -= n;
}
fp->_flags |= __SERR;
return (EOF);
}
}
return (0);
}
static int
sflush_locked(FILE *fp)
{
int ret;
FLOCKFILE_CANCELSAFE(fp);
ret = __sflush(fp);
FUNLOCKFILE_CANCELSAFE();
return (ret);
}