123 lines
3.0 KiB
C
123 lines
3.0 KiB
C
|
/*-
|
||
|
|
* Copyright (c) 2009-2011, Juniper Networks, Inc.
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY JUNIPER NETWORKS 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 JUNIPER NETWORKS 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>
|
||
|
|
__FBSDID("$FreeBSD$");
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_filemon_lock(struct filemon *filemon)
|
||
|
|
{
|
||
|
|
mtx_lock(&filemon->mtx);
|
||
|
|
|
||
|
|
while (filemon->locker != NULL && filemon->locker != curthread)
|
||
|
|
cv_wait(&filemon->cv, &filemon->mtx);
|
||
|
|
|
||
|
|
filemon->locker = curthread;
|
||
|
|
|
||
|
|
mtx_unlock(&filemon->mtx);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_filemon_unlock(struct filemon *filemon)
|
||
|
|
{
|
||
|
|
mtx_lock(&filemon->mtx);
|
||
|
|
|
||
|
|
if (filemon->locker == curthread)
|
||
|
|
filemon->locker = NULL;
|
||
|
|
|
||
|
|
/* Wake up threads waiting. */
|
||
|
|
cv_broadcast(&filemon->cv);
|
||
|
|
|
||
|
|
mtx_unlock(&filemon->mtx);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_lock_read(void)
|
||
|
|
{
|
||
|
|
mtx_lock(&access_mtx);
|
||
|
|
|
||
|
|
while (access_owner != NULL || access_requester != NULL)
|
||
|
|
cv_wait(&access_cv, &access_mtx);
|
||
|
|
|
||
|
|
n_readers++;
|
||
|
|
|
||
|
|
/* Wake up threads waiting. */
|
||
|
|
cv_broadcast(&access_cv);
|
||
|
|
|
||
|
|
mtx_unlock(&access_mtx);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_unlock_read(void)
|
||
|
|
{
|
||
|
|
mtx_lock(&access_mtx);
|
||
|
|
|
||
|
|
if (n_readers > 0)
|
||
|
|
n_readers--;
|
||
|
|
|
||
|
|
/* Wake up a thread waiting. */
|
||
|
|
cv_broadcast(&access_cv);
|
||
|
|
|
||
|
|
mtx_unlock(&access_mtx);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_lock_write(void)
|
||
|
|
{
|
||
|
|
mtx_lock(&access_mtx);
|
||
|
|
|
||
|
|
while (access_owner != curthread) {
|
||
|
|
if (access_owner == NULL &&
|
||
|
|
(access_requester == NULL ||
|
||
|
|
access_requester == curthread)) {
|
||
|
|
access_owner = curthread;
|
||
|
|
access_requester = NULL;
|
||
|
|
} else {
|
||
|
|
if (access_requester == NULL)
|
||
|
|
access_requester = curthread;
|
||
|
|
|
||
|
|
cv_wait(&access_cv, &access_mtx);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
mtx_unlock(&access_mtx);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
filemon_unlock_write(void)
|
||
|
|
{
|
||
|
|
mtx_lock(&access_mtx);
|
||
|
|
|
||
|
|
/* Sanity check that the current thread actually has the write lock. */
|
||
|
|
if (access_owner == curthread)
|
||
|
|
access_owner = NULL;
|
||
|
|
|
||
|
|
/* Wake up a thread waiting. */
|
||
|
|
cv_broadcast(&access_cv);
|
||
|
|
|
||
|
|
mtx_unlock(&access_mtx);
|
||
|
|
}
|