NetBSD/lib/libpthread/pthread_cond.c

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/* $NetBSD: pthread_cond.c,v 1.11 2003/04/23 19:36:12 nathanw Exp $ */
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/*-
* Copyright (c) 2001 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>
__RCSID("$NetBSD: pthread_cond.c,v 1.11 2003/04/23 19:36:12 nathanw Exp $");
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#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
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#include "pthread.h"
#include "pthread_int.h"
#ifdef PTHREAD_COND_DEBUG
#define SDPRINTF(x) DPRINTF(x)
#else
#define SDPRINTF(x)
#endif
int _sys_select(int, fd_set *, fd_set *, fd_set *, struct timeval *);
extern int pthread__started;
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static void pthread_cond_wait__callback(void *);
static int pthread_cond_wait_nothread(pthread_t, pthread_mutex_t *,
const struct timespec *);
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__strong_alias(__libc_cond_init,pthread_cond_init)
__strong_alias(__libc_cond_signal,pthread_cond_signal)
__strong_alias(__libc_cond_broadcast,pthread_cond_broadcast)
__strong_alias(__libc_cond_wait,pthread_cond_wait)
__strong_alias(__libc_cond_timedwait,pthread_cond_timedwait)
__strong_alias(__libc_cond_destroy,pthread_cond_destroy)
int
pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
{
pthread__error(EINVAL, "Invalid condition variable attribute",
(attr == NULL) || (attr->ptca_magic == _PT_CONDATTR_MAGIC));
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cond->ptc_magic = _PT_COND_MAGIC;
pthread_lockinit(&cond->ptc_lock);
PTQ_INIT(&cond->ptc_waiters);
cond->ptc_mutex = NULL;
return 0;
}
int
pthread_cond_destroy(pthread_cond_t *cond)
{
pthread__error(EINVAL, "Invalid condition variable",
cond->ptc_magic == _PT_COND_MAGIC);
pthread__error(EBUSY, "Destroying condition variable in use",
cond->ptc_mutex == NULL);
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cond->ptc_magic = _PT_COND_DEAD;
return 0;
}
int
pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
{
pthread_t self;
pthread__error(EINVAL, "Invalid condition variable",
cond->ptc_magic == _PT_COND_MAGIC);
pthread__error(EINVAL, "Invalid mutex",
mutex->ptm_magic == _PT_MUTEX_MAGIC);
pthread__error(EPERM, "Mutex not locked in condition wait",
mutex->ptm_lock == __SIMPLELOCK_LOCKED);
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self = pthread__self();
PTHREADD_ADD(PTHREADD_COND_WAIT);
/* Just hang out for a while if threads aren't running yet. */
if (__predict_false(pthread__started == 0))
return pthread_cond_wait_nothread(self, mutex, NULL);
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pthread_spinlock(self, &cond->ptc_lock);
#ifdef ERRORCHECK
if (cond->ptc_mutex == NULL)
cond->ptc_mutex = mutex;
else
pthread__error(EINVAL,
"Multiple mutexes used for condition wait",
cond->ptc_mutex == mutex);
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#endif
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SDPRINTF(("(cond wait %p) Waiting on %p, mutex %p\n",
self, cond, mutex));
pthread_spinlock(self, &self->pt_statelock);
if (self->pt_cancel) {
pthread_spinunlock(self, &self->pt_statelock);
pthread_spinunlock(self, &cond->ptc_lock);
pthread_exit(PTHREAD_CANCELED);
}
self->pt_state = PT_STATE_BLOCKED_QUEUE;
self->pt_sleepobj = cond;
self->pt_sleepq = &cond->ptc_waiters;
self->pt_sleeplock = &cond->ptc_lock;
pthread_spinunlock(self, &self->pt_statelock);
PTQ_INSERT_HEAD(&cond->ptc_waiters, self, pt_sleep);
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pthread_mutex_unlock(mutex);
pthread__block(self, &cond->ptc_lock);
/* Spinlock is unlocked on return */
pthread_mutex_lock(mutex);
pthread__testcancel(self);
SDPRINTF(("(cond wait %p) Woke up on %p, mutex %p\n",
self, cond, mutex));
return 0;
}
struct pthread_cond__waitarg {
pthread_t ptw_thread;
pthread_cond_t *ptw_cond;
};
int
pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
const struct timespec *abstime)
{
pthread_t self;
struct pthread_cond__waitarg wait;
struct pt_alarm_t alarm;
int retval;
pthread__error(EINVAL, "Invalid condition variable",
cond->ptc_magic == _PT_COND_MAGIC);
pthread__error(EINVAL, "Invalid mutex",
mutex->ptm_magic == _PT_MUTEX_MAGIC);
pthread__error(EPERM, "Mutex not locked in condition wait",
mutex->ptm_lock == __SIMPLELOCK_LOCKED);
pthread__error(EINVAL, "Invalid wait time",
(abstime->tv_sec >= 0) &&
(abstime->tv_nsec >= 0) && (abstime->tv_nsec < 1000000000));
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self = pthread__self();
PTHREADD_ADD(PTHREADD_COND_TIMEDWAIT);
/* Just hang out for a while if threads aren't running yet. */
if (__predict_false(pthread__started == 0))
return pthread_cond_wait_nothread(self, mutex, abstime);
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pthread_spinlock(self, &cond->ptc_lock);
#ifdef ERRORCHECK
if (cond->ptc_mutex == NULL)
cond->ptc_mutex = mutex;
else
pthread__error(EINVAL,
"Multiple mutexes used for condition wait",
cond->ptc_mutex == mutex);
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#endif
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wait.ptw_thread = self;
wait.ptw_cond = cond;
retval = 0;
SDPRINTF(("(cond timed wait %p) Waiting on %p until %d.%06ld\n",
self, cond, abstime->tv_sec, abstime->tv_nsec/1000));
pthread_spinlock(self, &self->pt_statelock);
if (self->pt_cancel) {
pthread_spinunlock(self, &self->pt_statelock);
pthread_spinunlock(self, &cond->ptc_lock);
pthread_exit(PTHREAD_CANCELED);
}
pthread__alarm_add(self, &alarm, abstime, pthread_cond_wait__callback,
&wait);
self->pt_state = PT_STATE_BLOCKED_QUEUE;
self->pt_sleepobj = cond;
self->pt_sleepq = &cond->ptc_waiters;
self->pt_sleeplock = &cond->ptc_lock;
pthread_spinunlock(self, &self->pt_statelock);
PTQ_INSERT_HEAD(&cond->ptc_waiters, self, pt_sleep);
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pthread_mutex_unlock(mutex);
pthread__block(self, &cond->ptc_lock);
/* Spinlock is unlocked on return */
SDPRINTF(("(cond timed wait %p) Woke up on %p, mutex %p\n",
self, cond));
pthread__alarm_del(self, &alarm);
if (pthread__alarm_fired(&alarm))
retval = ETIMEDOUT;
SDPRINTF(("(cond timed wait %p) %s\n",
self, (retval == ETIMEDOUT) ? "(timed out)" : ""));
pthread_mutex_lock(mutex);
pthread__testcancel(self);
return retval;
}
static void
pthread_cond_wait__callback(void *arg)
{
struct pthread_cond__waitarg *a;
pthread_t self;
a = arg;
self = pthread__self();
/*
* Don't dequeue and schedule the thread if it's already been
* queued up by a signal or broadcast (but hasn't yet run as far
* as pthread__alarm_del(), or we wouldn't be here, and hence can't
* have become blocked on some *other* queue).
*/
pthread_spinlock(self, &a->ptw_cond->ptc_lock);
if (a->ptw_thread->pt_state == PT_STATE_BLOCKED_QUEUE) {
PTQ_REMOVE(&a->ptw_cond->ptc_waiters, a->ptw_thread, pt_sleep);
#ifdef ERRORCHECK
if (PTQ_EMPTY(&a->ptw_cond->ptc_waiters))
a->ptw_cond->ptc_mutex = NULL;
#endif
pthread__sched(self, a->ptw_thread);
}
pthread_spinunlock(self, &a->ptw_cond->ptc_lock);
}
int
pthread_cond_signal(pthread_cond_t *cond)
{
pthread_t self, signaled;
pthread__error(EINVAL, "Invalid condition variable",
cond->ptc_magic == _PT_COND_MAGIC);
PTHREADD_ADD(PTHREADD_COND_SIGNAL);
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SDPRINTF(("(cond signal %p) Signaling %p\n",
pthread__self(), cond));
if (!PTQ_EMPTY(&cond->ptc_waiters)) {
self = pthread__self();
pthread_spinlock(self, &cond->ptc_lock);
signaled = PTQ_FIRST(&cond->ptc_waiters);
if (signaled != NULL)
PTQ_REMOVE(&cond->ptc_waiters, signaled, pt_sleep);
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#ifdef ERRORCHECK
if (PTQ_EMPTY(&cond->ptc_waiters))
cond->ptc_mutex = NULL;
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#endif
pthread_spinunlock(self, &cond->ptc_lock);
if (signaled != NULL) {
pthread__sched(self, signaled);
PTHREADD_ADD(PTHREADD_COND_WOKEUP);
}
}
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return 0;
}
int
pthread_cond_broadcast(pthread_cond_t *cond)
{
pthread_t self;
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struct pthread_queue_t blockedq;
pthread__error(EINVAL, "Invalid condition variable", cond->ptc_magic == _PT_COND_MAGIC);
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PTHREADD_ADD(PTHREADD_COND_BROADCAST);
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SDPRINTF(("(cond signal %p) Broadcasting %p\n",
pthread__self(), cond));
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if (!PTQ_EMPTY(&cond->ptc_waiters)) {
self = pthread__self();
pthread_spinlock(self, &cond->ptc_lock);
blockedq = cond->ptc_waiters;
PTQ_INIT(&cond->ptc_waiters);
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#ifdef ERRORCHECK
cond->ptc_mutex = NULL;
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#endif
pthread_spinunlock(self, &cond->ptc_lock);
pthread__sched_sleepers(self, &blockedq);
PTHREADD_ADD(PTHREADD_COND_WOKEUP);
}
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return 0;
}
int
pthread_condattr_init(pthread_condattr_t *attr)
{
attr->ptca_magic = _PT_CONDATTR_MAGIC;
return 0;
}
int
pthread_condattr_destroy(pthread_condattr_t *attr)
{
pthread__error(EINVAL, "Invalid condition variable attribute",
attr->ptca_magic == _PT_CONDATTR_MAGIC);
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attr->ptca_magic = _PT_CONDATTR_DEAD;
return 0;
}
/* Utility routine to hang out for a while if threads haven't started yet. */
static int
pthread_cond_wait_nothread(pthread_t self, pthread_mutex_t *mutex,
const struct timespec *abstime)
{
struct timeval now, tv, *tvp;
int retval;
if (abstime == NULL)
tvp = NULL;
else {
tvp = &tv;
gettimeofday(&now, NULL);
TIMESPEC_TO_TIMEVAL(tvp, abstime);
timersub(tvp, &now, tvp);
}
/*
* The libpthread select() wrapper has cancellation tests, but
* we need to have the mutex locked when testing for
* cancellation and unlocked while we sleep. So, skip the
* wrapper.
*/
pthread__testcancel(self);
pthread_mutex_unlock(mutex);
retval = _sys_select(0, NULL, NULL, NULL, tvp);
pthread_mutex_lock(mutex);
pthread__testcancel(self);
if (retval == 0)
return ETIMEDOUT;
else
return EINTR;
}