HardenedBSD/lib/libc/stdio/fflush.c
Warner Losh dc36d6f9bb lib: Remove ancient SCCS tags.
Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by:		Netflix
2023-11-26 22:23:28 -07:00

148 lines
4.0 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.
*/
#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);
}
__weak_reference(__fflush, fflush_unlocked);
int
__sflush(FILE *fp)
{
unsigned char *p;
int n, f, t;
f = fp->_flags;
if ((f & __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 = f & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
for (; n > 0; n -= t, p += t) {
t = _swrite(fp, (char *)p, n);
if (t <= 0) {
if (p > fp->_p)
/* Some was written. */
memmove(fp->_p, p, n);
/* Reset _p and _w. */
fp->_p += n;
if ((fp->_flags & __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);
}