540 lines
13 KiB
C
540 lines
13 KiB
C
/*
|
|
* Copyright (c) 1995 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 AUTHOR 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.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
#include <pthread.h>
|
|
#include "thr_private.h"
|
|
|
|
/*
|
|
* Proctect two different threads calling a pthread_cond_* function
|
|
* from accidentally initializing the condition variable twice.
|
|
*/
|
|
static spinlock_t static_cond_lock = _SPINLOCK_INITIALIZER;
|
|
|
|
/*
|
|
* Prototypes
|
|
*/
|
|
static inline int cond_init(pthread_cond_t *);
|
|
static pthread_t cond_queue_deq(pthread_cond_t);
|
|
static void cond_queue_remove(pthread_cond_t, pthread_t);
|
|
static void cond_queue_enq(pthread_cond_t, pthread_t);
|
|
static int cond_signal(pthread_cond_t *, int);
|
|
static int cond_wait_common(pthread_cond_t *,
|
|
pthread_mutex_t *, const struct timespec *);
|
|
|
|
__weak_reference(_pthread_cond_init, pthread_cond_init);
|
|
__weak_reference(_pthread_cond_destroy, pthread_cond_destroy);
|
|
__weak_reference(_pthread_cond_wait, pthread_cond_wait);
|
|
__weak_reference(_pthread_cond_timedwait, pthread_cond_timedwait);
|
|
__weak_reference(_pthread_cond_signal, pthread_cond_signal);
|
|
__weak_reference(_pthread_cond_broadcast, pthread_cond_broadcast);
|
|
|
|
#define COND_LOCK(c) \
|
|
do { \
|
|
if (umtx_lock(&(c)->c_lock, curthread->thr_id)) \
|
|
abort(); \
|
|
} while (0)
|
|
|
|
#define COND_UNLOCK(c) \
|
|
do { \
|
|
if (umtx_unlock(&(c)->c_lock, curthread->thr_id)) \
|
|
abort(); \
|
|
} while (0)
|
|
|
|
|
|
/* Reinitialize a condition variable to defaults. */
|
|
int
|
|
_cond_reinit(pthread_cond_t *cond)
|
|
{
|
|
if (cond == NULL)
|
|
return (EINVAL);
|
|
|
|
if (*cond == NULL)
|
|
return (pthread_cond_init(cond, NULL));
|
|
|
|
/*
|
|
* Initialize the condition variable structure:
|
|
*/
|
|
TAILQ_INIT(&(*cond)->c_queue);
|
|
(*cond)->c_flags = COND_FLAGS_INITED;
|
|
(*cond)->c_type = COND_TYPE_FAST;
|
|
(*cond)->c_mutex = NULL;
|
|
(*cond)->c_seqno = 0;
|
|
bzero(&(*cond)->c_lock, sizeof((*cond)->c_lock));
|
|
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
_pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
|
|
{
|
|
enum pthread_cond_type type;
|
|
pthread_cond_t pcond;
|
|
|
|
if (cond == NULL)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* Check if a pointer to a condition variable attribute
|
|
* structure was passed by the caller:
|
|
*/
|
|
if (cond_attr != NULL && *cond_attr != NULL)
|
|
type = (*cond_attr)->c_type;
|
|
else
|
|
/* Default to a fast condition variable: */
|
|
type = COND_TYPE_FAST;
|
|
|
|
/* Process according to condition variable type: */
|
|
switch (type) {
|
|
case COND_TYPE_FAST:
|
|
break;
|
|
default:
|
|
return (EINVAL);
|
|
break;
|
|
}
|
|
|
|
if ((pcond = (pthread_cond_t)
|
|
malloc(sizeof(struct pthread_cond))) == NULL)
|
|
return (ENOMEM);
|
|
/*
|
|
* Initialise the condition variable
|
|
* structure:
|
|
*/
|
|
TAILQ_INIT(&pcond->c_queue);
|
|
pcond->c_flags |= COND_FLAGS_INITED;
|
|
pcond->c_type = type;
|
|
pcond->c_mutex = NULL;
|
|
pcond->c_seqno = 0;
|
|
bzero(&pcond->c_lock, sizeof(pcond->c_lock));
|
|
|
|
*cond = pcond;
|
|
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
_pthread_cond_destroy(pthread_cond_t *cond)
|
|
{
|
|
if (cond == NULL || *cond == NULL)
|
|
return (EINVAL);
|
|
|
|
COND_LOCK(*cond);
|
|
|
|
/*
|
|
* Free the memory allocated for the condition
|
|
* variable structure:
|
|
*/
|
|
free(*cond);
|
|
|
|
/*
|
|
* NULL the caller's pointer now that the condition
|
|
* variable has been destroyed:
|
|
*/
|
|
*cond = NULL;
|
|
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
_pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
|
|
{
|
|
int rval;
|
|
|
|
rval = cond_wait_common(cond, mutex, NULL);
|
|
|
|
/* This should never happen. */
|
|
if (rval == ETIMEDOUT)
|
|
abort();
|
|
|
|
return (rval);
|
|
}
|
|
|
|
int
|
|
_pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
|
|
const struct timespec * abstime)
|
|
{
|
|
if (abstime == NULL || abstime->tv_nsec >= 1000000000)
|
|
return (EINVAL);
|
|
|
|
return (cond_wait_common(cond, mutex, abstime));
|
|
}
|
|
|
|
static int
|
|
cond_wait_common(pthread_cond_t * cond, pthread_mutex_t * mutex,
|
|
const struct timespec * abstime)
|
|
{
|
|
int rval = 0;
|
|
int done = 0;
|
|
int seqno;
|
|
int mtxrval;
|
|
|
|
|
|
_thread_enter_cancellation_point();
|
|
|
|
if (cond == NULL)
|
|
return (EINVAL);
|
|
/*
|
|
* If the condition variable is statically initialized, perform dynamic
|
|
* initialization.
|
|
*/
|
|
if (*cond == PTHREAD_COND_INITIALIZER && (rval = cond_init(cond)) != 0)
|
|
return (rval);
|
|
|
|
|
|
COND_LOCK(*cond);
|
|
|
|
/*
|
|
* If the condvar was statically allocated, properly
|
|
* initialize the tail queue.
|
|
*/
|
|
if (((*cond)->c_flags & COND_FLAGS_INITED) == 0) {
|
|
TAILQ_INIT(&(*cond)->c_queue);
|
|
(*cond)->c_flags |= COND_FLAGS_INITED;
|
|
}
|
|
|
|
/* Process according to condition variable type. */
|
|
|
|
switch ((*cond)->c_type) {
|
|
/* Fast condition variable: */
|
|
case COND_TYPE_FAST:
|
|
if ((mutex == NULL) || (((*cond)->c_mutex != NULL) &&
|
|
((*cond)->c_mutex != *mutex))) {
|
|
COND_UNLOCK(*cond);
|
|
rval = EINVAL;
|
|
break;
|
|
}
|
|
/* Remember the mutex */
|
|
(*cond)->c_mutex = *mutex;
|
|
|
|
if ((rval = _mutex_cv_unlock(mutex)) != 0) {
|
|
if (rval == -1){
|
|
printf("foo");
|
|
fflush(stdout);
|
|
abort();
|
|
}
|
|
|
|
COND_UNLOCK(*cond);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We need to protect the queue operations. It also
|
|
* protects c_seqno and the pthread flag fields. This is
|
|
* dropped before calling _thread_suspend() and reaquired
|
|
* when we return.
|
|
*/
|
|
|
|
_thread_critical_enter(curthread);
|
|
/*
|
|
* c_seqno is protected.
|
|
*/
|
|
seqno = (*cond)->c_seqno;
|
|
|
|
do {
|
|
/*
|
|
* Queue the running thread on the condition
|
|
* variable.
|
|
*/
|
|
cond_queue_enq(*cond, curthread);
|
|
|
|
if (curthread->cancelflags & PTHREAD_CANCELLING) {
|
|
/*
|
|
* POSIX Says that we must relock the mutex
|
|
* even if we're being canceled.
|
|
*/
|
|
_thread_critical_exit(curthread);
|
|
COND_UNLOCK(*cond);
|
|
_mutex_cv_lock(mutex);
|
|
pthread_testcancel();
|
|
PANIC("Shouldn't have come back.");
|
|
}
|
|
|
|
PTHREAD_SET_STATE(curthread, PS_COND_WAIT);
|
|
_thread_critical_exit(curthread);
|
|
COND_UNLOCK(*cond);
|
|
rval = _thread_suspend(curthread, (struct timespec *)abstime);
|
|
if (rval != 0 && rval != EAGAIN && rval != EINTR) {
|
|
printf("foo");
|
|
fflush(stdout);
|
|
abort();
|
|
}
|
|
COND_LOCK(*cond);
|
|
_thread_critical_enter(curthread);
|
|
|
|
done = (seqno != (*cond)->c_seqno);
|
|
|
|
/*
|
|
* If we timed out, this will remove us from the
|
|
* queue. Otherwise, if we were signaled it does
|
|
* nothing because this thread won't be on the queue.
|
|
*/
|
|
cond_queue_remove(*cond, curthread);
|
|
|
|
} while ((done == 0) && (rval == 0));
|
|
/*
|
|
* If we timed out someone still may have signaled us
|
|
* before we got a chance to run again. We check for
|
|
* this by looking to see if our state is RUNNING.
|
|
*/
|
|
if (rval == EAGAIN) {
|
|
if (curthread->state != PS_RUNNING) {
|
|
PTHREAD_SET_STATE(curthread, PS_RUNNING);
|
|
rval = ETIMEDOUT;
|
|
} else
|
|
rval = 0;
|
|
}
|
|
_thread_critical_exit(curthread);
|
|
COND_UNLOCK(*cond);
|
|
|
|
mtxrval = _mutex_cv_lock(mutex);
|
|
|
|
/*
|
|
* If the mutex failed return that error, otherwise we're
|
|
* returning ETIMEDOUT.
|
|
*/
|
|
if (mtxrval == -1) {
|
|
printf("foo");
|
|
fflush(stdout);
|
|
abort();
|
|
}
|
|
if (mtxrval != 0)
|
|
rval = mtxrval;
|
|
|
|
break;
|
|
|
|
/* Trap invalid condition variable types: */
|
|
default:
|
|
COND_UNLOCK(*cond);
|
|
rval = EINVAL;
|
|
break;
|
|
}
|
|
|
|
_thread_leave_cancellation_point();
|
|
|
|
return (rval);
|
|
}
|
|
|
|
int
|
|
_pthread_cond_signal(pthread_cond_t * cond)
|
|
{
|
|
return (cond_signal(cond, 0));
|
|
}
|
|
|
|
int
|
|
_pthread_cond_broadcast(pthread_cond_t * cond)
|
|
{
|
|
return (cond_signal(cond, 1));
|
|
}
|
|
|
|
static int
|
|
cond_signal(pthread_cond_t * cond, int broadcast)
|
|
{
|
|
int rval = 0;
|
|
pthread_t pthread;
|
|
|
|
if (cond == NULL)
|
|
return (EINVAL);
|
|
/*
|
|
* If the condition variable is statically initialized, perform dynamic
|
|
* initialization.
|
|
*/
|
|
if (*cond == PTHREAD_COND_INITIALIZER && (rval = cond_init(cond)) != 0)
|
|
return (rval);
|
|
|
|
COND_LOCK(*cond);
|
|
|
|
/* Process according to condition variable type: */
|
|
switch ((*cond)->c_type) {
|
|
/* Fast condition variable: */
|
|
case COND_TYPE_FAST:
|
|
(*cond)->c_seqno++;
|
|
|
|
/*
|
|
* Enter a loop to bring all (or only one) threads off the
|
|
* condition queue:
|
|
*/
|
|
do {
|
|
/*
|
|
* Wake up the signaled thread. It will be returned
|
|
* to us locked, and with signals disabled.
|
|
*/
|
|
if ((pthread = cond_queue_deq(*cond)) != NULL) {
|
|
PTHREAD_NEW_STATE(pthread, PS_RUNNING);
|
|
_thread_critical_exit(pthread);
|
|
}
|
|
} while (broadcast && pthread != NULL);
|
|
|
|
break;
|
|
|
|
/* Trap invalid condition variable types: */
|
|
default:
|
|
rval = EINVAL;
|
|
break;
|
|
}
|
|
|
|
COND_UNLOCK(*cond);
|
|
|
|
|
|
return (rval);
|
|
}
|
|
|
|
void
|
|
_cond_wait_backout(pthread_t pthread)
|
|
{
|
|
pthread_cond_t cond;
|
|
|
|
cond = pthread->data.cond;
|
|
if (cond == NULL)
|
|
return;
|
|
|
|
COND_LOCK(cond);
|
|
|
|
/* Process according to condition variable type: */
|
|
switch (cond->c_type) {
|
|
/* Fast condition variable: */
|
|
case COND_TYPE_FAST:
|
|
_thread_critical_enter(curthread);
|
|
|
|
cond_queue_remove(cond, pthread);
|
|
|
|
_thread_critical_exit(curthread);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
COND_UNLOCK(cond);
|
|
}
|
|
|
|
/*
|
|
* Dequeue a waiting thread from the head of a condition queue in
|
|
* descending priority order.
|
|
*/
|
|
static pthread_t
|
|
cond_queue_deq(pthread_cond_t cond)
|
|
{
|
|
pthread_t pthread;
|
|
|
|
while ((pthread = TAILQ_FIRST(&cond->c_queue)) != NULL) {
|
|
_thread_critical_enter(pthread);
|
|
TAILQ_REMOVE(&cond->c_queue, pthread, sqe);
|
|
cond_queue_remove(cond, pthread);
|
|
if ((pthread->cancelflags & PTHREAD_CANCELLING) == 0 &&
|
|
pthread->state == PS_COND_WAIT)
|
|
/*
|
|
* Only exit the loop when we find a thread
|
|
* that hasn't timed out or been canceled;
|
|
* those threads are already running and don't
|
|
* need their run state changed.
|
|
*/
|
|
break;
|
|
else
|
|
_thread_critical_exit(pthread);
|
|
}
|
|
|
|
return(pthread);
|
|
}
|
|
|
|
/*
|
|
* Remove a waiting thread from a condition queue in descending priority
|
|
* order.
|
|
*/
|
|
static void
|
|
cond_queue_remove(pthread_cond_t cond, pthread_t pthread)
|
|
{
|
|
/*
|
|
* Because pthread_cond_timedwait() can timeout as well
|
|
* as be signaled by another thread, it is necessary to
|
|
* guard against removing the thread from the queue if
|
|
* it isn't in the queue.
|
|
*/
|
|
if (pthread->flags & PTHREAD_FLAGS_IN_CONDQ) {
|
|
TAILQ_REMOVE(&cond->c_queue, pthread, sqe);
|
|
pthread->flags &= ~PTHREAD_FLAGS_IN_CONDQ;
|
|
}
|
|
/* Check for no more waiters. */
|
|
if (TAILQ_FIRST(&cond->c_queue) == NULL)
|
|
cond->c_mutex = NULL;
|
|
}
|
|
|
|
/*
|
|
* Enqueue a waiting thread to a condition queue in descending priority
|
|
* order.
|
|
*/
|
|
static void
|
|
cond_queue_enq(pthread_cond_t cond, pthread_t pthread)
|
|
{
|
|
pthread_t tid = TAILQ_LAST(&cond->c_queue, cond_head);
|
|
char *name;
|
|
|
|
name = pthread->name ? pthread->name : "unknown";
|
|
if ((pthread->flags & PTHREAD_FLAGS_IN_CONDQ) != 0)
|
|
_thread_printf(2, "Thread (%s:%u) already on condq\n",
|
|
pthread->name, pthread->uniqueid);
|
|
if ((pthread->flags & PTHREAD_FLAGS_IN_MUTEXQ) != 0)
|
|
_thread_printf(2, "Thread (%s:%u) already on mutexq\n",
|
|
pthread->name, pthread->uniqueid);
|
|
PTHREAD_ASSERT_NOT_IN_SYNCQ(pthread);
|
|
|
|
/*
|
|
* For the common case of all threads having equal priority,
|
|
* we perform a quick check against the priority of the thread
|
|
* at the tail of the queue.
|
|
*/
|
|
if ((tid == NULL) || (pthread->active_priority <= tid->active_priority))
|
|
TAILQ_INSERT_TAIL(&cond->c_queue, pthread, sqe);
|
|
else {
|
|
tid = TAILQ_FIRST(&cond->c_queue);
|
|
while (pthread->active_priority <= tid->active_priority)
|
|
tid = TAILQ_NEXT(tid, sqe);
|
|
TAILQ_INSERT_BEFORE(tid, pthread, sqe);
|
|
}
|
|
pthread->flags |= PTHREAD_FLAGS_IN_CONDQ;
|
|
pthread->data.cond = cond;
|
|
}
|
|
|
|
static inline int
|
|
cond_init(pthread_cond_t *cond)
|
|
{
|
|
int error = 0;
|
|
_SPINLOCK(&static_cond_lock);
|
|
if (*cond == PTHREAD_COND_INITIALIZER)
|
|
error = _pthread_cond_init(cond, NULL);
|
|
_SPINUNLOCK(&static_cond_lock);
|
|
return (error);
|
|
}
|
|
|