mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-30 12:04:07 +00:00
150 lines
4.2 KiB
C
150 lines
4.2 KiB
C
/*
|
|
* Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
|
|
* All rights reserved.
|
|
*
|
|
* 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 John Birrell.
|
|
* 4. Neither the name of the author nor the names of any co-contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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.
|
|
*/
|
|
|
|
/*
|
|
* POSIX stdio FILE locking functions. These assume that the locking
|
|
* is only required at FILE structure level, not at file descriptor
|
|
* level too.
|
|
*
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "namespace.h"
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <pthread.h>
|
|
#include "un-namespace.h"
|
|
|
|
#include "local.h"
|
|
|
|
|
|
/*
|
|
* Weak symbols for externally visible functions in this file:
|
|
*/
|
|
__weak_reference(_flockfile, flockfile);
|
|
__weak_reference(_flockfile_debug_stub, _flockfile_debug);
|
|
__weak_reference(_ftrylockfile, ftrylockfile);
|
|
__weak_reference(_funlockfile, funlockfile);
|
|
|
|
/*
|
|
* We need to retain binary compatibility for a while. So pretend
|
|
* that _lock is part of FILE * even though it is dereferenced off
|
|
* _extra now. When we stop encoding the size of FILE into binaries
|
|
* this can be changed in stdio.h. This will reduce the amount of
|
|
* code that has to change in the future (just remove this comment
|
|
* and #define).
|
|
*/
|
|
#define _lock _extra
|
|
|
|
void
|
|
_flockfile(FILE *fp)
|
|
{
|
|
pthread_t curthread = _pthread_self();
|
|
|
|
if (fp->_lock->fl_owner == curthread)
|
|
fp->_lock->fl_count++;
|
|
else {
|
|
/*
|
|
* Make sure this mutex is treated as a private
|
|
* internal mutex:
|
|
*/
|
|
_pthread_mutex_lock(&fp->_lock->fl_mutex);
|
|
fp->_lock->fl_owner = curthread;
|
|
fp->_lock->fl_count = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This can be overriden by the threads library if it is linked in.
|
|
*/
|
|
void
|
|
_flockfile_debug_stub(FILE *fp, char *fname, int lineno)
|
|
{
|
|
_flockfile(fp);
|
|
}
|
|
|
|
int
|
|
_ftrylockfile(FILE *fp)
|
|
{
|
|
pthread_t curthread = _pthread_self();
|
|
int ret = 0;
|
|
|
|
if (fp->_lock->fl_owner == curthread)
|
|
fp->_lock->fl_count++;
|
|
/*
|
|
* Make sure this mutex is treated as a private
|
|
* internal mutex:
|
|
*/
|
|
else if (_pthread_mutex_trylock(&fp->_lock->fl_mutex) == 0) {
|
|
fp->_lock->fl_owner = curthread;
|
|
fp->_lock->fl_count = 1;
|
|
}
|
|
else
|
|
ret = -1;
|
|
return (ret);
|
|
}
|
|
|
|
void
|
|
_funlockfile(FILE *fp)
|
|
{
|
|
pthread_t curthread = _pthread_self();
|
|
|
|
/*
|
|
* Check if this file is owned by the current thread:
|
|
*/
|
|
if (fp->_lock->fl_owner == curthread) {
|
|
/*
|
|
* Check if this thread has locked the FILE
|
|
* more than once:
|
|
*/
|
|
if (fp->_lock->fl_count > 1)
|
|
/*
|
|
* Decrement the count of the number of
|
|
* times the running thread has locked this
|
|
* file:
|
|
*/
|
|
fp->_lock->fl_count--;
|
|
else {
|
|
/*
|
|
* The running thread will release the
|
|
* lock now:
|
|
*/
|
|
fp->_lock->fl_count = 0;
|
|
fp->_lock->fl_owner = NULL;
|
|
_pthread_mutex_unlock(&fp->_lock->fl_mutex);
|
|
}
|
|
}
|
|
}
|