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 $ */
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/*-
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* Copyright (c) 2002 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nathan J. Williams.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: flockfile.c,v 1.4 2003/02/01 03:25:00 nathanw Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <assert.h>
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include "reentrant.h"
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#include "local.h"
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#ifdef __weak_alias
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__weak_alias(flockfile,_flockfile)
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__weak_alias(ftrylockfile,_ftrylockfile)
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__weak_alias(funlockfile,_funlockfile)
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#endif
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#ifdef _REENTRANT
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/*
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* XXX This code makes the assumption that a thr_t (pthread_t) is a
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* XXX pointer.
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*/
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extern int __isthreaded;
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void
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flockfile(FILE *fp)
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{
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if (__isthreaded == 0)
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return;
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mutex_lock(&_LOCK(fp));
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if (_LOCKOWNER(fp) == thr_self()) {
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_LOCKCOUNT(fp)++;
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} else {
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while (_LOCKOWNER(fp) != NULL)
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cond_wait(&_LOCKCOND(fp), &_LOCK(fp));
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_LOCKOWNER(fp) = thr_self();
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_LOCKCOUNT(fp) = 1;
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}
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mutex_unlock(&_LOCK(fp));
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}
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int
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ftrylockfile(FILE *fp)
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{
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int retval;
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if (__isthreaded == 0)
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return 0;
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retval = 0;
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mutex_lock(&_LOCK(fp));
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if (_LOCKOWNER(fp) == thr_self()) {
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_LOCKCOUNT(fp)++;
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} else if (_LOCKOWNER(fp) == NULL) {
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_LOCKOWNER(fp) = thr_self();
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_LOCKCOUNT(fp) = 1;
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} else
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retval = -1;
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mutex_unlock(&_LOCK(fp));
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return retval;
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}
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void
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funlockfile(FILE *fp)
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{
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if (__isthreaded == 0)
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return;
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mutex_lock(&_LOCK(fp));
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_LOCKCOUNT(fp)--;
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if (_LOCKCOUNT(fp) == 0) {
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_LOCKOWNER(fp) = NULL;
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cond_signal(&_LOCKCOND(fp));
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}
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mutex_unlock(&_LOCK(fp));
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}
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#else /* _REENTRANT */
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void
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flockfile(FILE *fp)
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{
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/* LINTED deliberate lack of effect */
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(void)fp;
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return;
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}
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int
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ftrylockfile(FILE *fp)
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{
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/* LINTED deliberate lack of effect */
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(void)fp;
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return (0);
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}
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void
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funlockfile(FILE *fp)
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{
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/* LINTED deliberate lack of effect */
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(void)fp;
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return;
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}
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#endif /* _REENTRANT */
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