34c915eb3d
trouble is caused by the memory allocation in the mutex initialization, and uncontested mutexes and condition variables have become faster in the meantime.
160 lines
3.7 KiB
C
160 lines
3.7 KiB
C
/* $NetBSD: flockfile.c,v 1.4 2003/02/01 03:25:00 nathanw Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 2002 The NetBSD Foundation, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to The NetBSD Foundation
|
|
* by Nathan J. Williams.
|
|
*
|
|
* 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 NetBSD
|
|
* Foundation, Inc. and its contributors.
|
|
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <sys/cdefs.h>
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
__RCSID("$NetBSD: flockfile.c,v 1.4 2003/02/01 03:25:00 nathanw Exp $");
|
|
#endif /* LIBC_SCCS and not lint */
|
|
|
|
#include "namespace.h"
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include "reentrant.h"
|
|
#include "local.h"
|
|
|
|
#ifdef __weak_alias
|
|
__weak_alias(flockfile,_flockfile)
|
|
__weak_alias(ftrylockfile,_ftrylockfile)
|
|
__weak_alias(funlockfile,_funlockfile)
|
|
#endif
|
|
|
|
#ifdef _REENTRANT
|
|
/*
|
|
* XXX This code makes the assumption that a thr_t (pthread_t) is a
|
|
* XXX pointer.
|
|
*/
|
|
|
|
extern int __isthreaded;
|
|
|
|
void
|
|
flockfile(FILE *fp)
|
|
{
|
|
|
|
if (__isthreaded == 0)
|
|
return;
|
|
|
|
mutex_lock(&_LOCK(fp));
|
|
|
|
if (_LOCKOWNER(fp) == thr_self()) {
|
|
_LOCKCOUNT(fp)++;
|
|
} else {
|
|
while (_LOCKOWNER(fp) != NULL)
|
|
cond_wait(&_LOCKCOND(fp), &_LOCK(fp));
|
|
_LOCKOWNER(fp) = thr_self();
|
|
_LOCKCOUNT(fp) = 1;
|
|
}
|
|
|
|
mutex_unlock(&_LOCK(fp));
|
|
}
|
|
|
|
int
|
|
ftrylockfile(FILE *fp)
|
|
{
|
|
int retval;
|
|
|
|
if (__isthreaded == 0)
|
|
return 0;
|
|
|
|
retval = 0;
|
|
mutex_lock(&_LOCK(fp));
|
|
|
|
if (_LOCKOWNER(fp) == thr_self()) {
|
|
_LOCKCOUNT(fp)++;
|
|
} else if (_LOCKOWNER(fp) == NULL) {
|
|
_LOCKOWNER(fp) = thr_self();
|
|
_LOCKCOUNT(fp) = 1;
|
|
} else
|
|
retval = -1;
|
|
|
|
mutex_unlock(&_LOCK(fp));
|
|
|
|
return retval;
|
|
}
|
|
|
|
void
|
|
funlockfile(FILE *fp)
|
|
{
|
|
|
|
if (__isthreaded == 0)
|
|
return;
|
|
|
|
mutex_lock(&_LOCK(fp));
|
|
|
|
_LOCKCOUNT(fp)--;
|
|
if (_LOCKCOUNT(fp) == 0) {
|
|
_LOCKOWNER(fp) = NULL;
|
|
cond_signal(&_LOCKCOND(fp));
|
|
}
|
|
|
|
mutex_unlock(&_LOCK(fp));
|
|
}
|
|
|
|
#else /* _REENTRANT */
|
|
|
|
void
|
|
flockfile(FILE *fp)
|
|
{
|
|
/* LINTED deliberate lack of effect */
|
|
(void)fp;
|
|
|
|
return;
|
|
}
|
|
|
|
int
|
|
ftrylockfile(FILE *fp)
|
|
{
|
|
/* LINTED deliberate lack of effect */
|
|
(void)fp;
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
funlockfile(FILE *fp)
|
|
{
|
|
/* LINTED deliberate lack of effect */
|
|
(void)fp;
|
|
|
|
return;
|
|
}
|
|
|
|
#endif /* _REENTRANT */
|