IABSD.fr/src/lib/libc/thread/rthread_cond.c

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• Author : mpi
  Date : 2019-01-29 17:40:26
  Hash : f3cfced6
  Message : There's no point in asserting that a pointer is not NULL before dereferencing it. ok kettenis@, visa@

• lib/libc/thread/rthread_cond.c

• /*	$OpenBSD: rthread_cond.c,v 1.5 2019/01/29 17:40:26 mpi Exp $ */
  /*
   * Copyright (c) 2017 Martin Pieuchot <mpi@openbsd.org>
   * Copyright (c) 2012 Philip Guenther <guenther@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <errno.h>
  #include <pthread.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include "rthread.h"
  #include "cancel.h"
  #include "synch.h"
  
  int
  pthread_cond_init(pthread_cond_t *condp, const pthread_condattr_t *attr)
  {
  	pthread_cond_t cond;
  
  	cond = calloc(1, sizeof(*cond));
  	if (cond == NULL)
  		return (ENOMEM);
  
  	if (attr == NULL)
  		cond->clock = CLOCK_REALTIME;
  	else
  		cond->clock = (*attr)->ca_clock;
  	*condp = cond;
  
  	return (0);
  }
  DEF_STRONG(pthread_cond_init);
  
  int
  pthread_cond_destroy(pthread_cond_t *condp)
  {
  	pthread_cond_t cond;
  
  	cond = *condp;
  
  	if (cond != NULL) {
  		if (cond->mutex != NULL) {
  #define MSG "pthread_cond_destroy on condvar with waiters!\n"
  			write(2, MSG, sizeof(MSG) - 1);
  #undef MSG
  			return (EBUSY);
  		}
  		free(cond);
  	}
  	*condp = NULL;
  
  	return (0);
  }
  
  int
  _rthread_cond_timedwait(pthread_cond_t cond, pthread_mutex_t *mutexp,
      const struct timespec *abs)
  {
  	struct pthread_mutex *mutex = (struct pthread_mutex *)*mutexp;
  	struct tib *tib = TIB_GET();
  	pthread_t self = tib->tib_thread;
  	int error, rv = 0, canceled = 0, mutex_count = 0;
  	clockid_t clock = cond->clock;
  	int seq = cond->seq;
  	PREP_CANCEL_POINT(tib);
  
  	_rthread_debug(5, "%p: cond_timed %p,%p (%p)\n", self,
  	    (void *)cond, (void *)mutex, (void *)mutex->owner);
  
  	ENTER_DELAYED_CANCEL_POINT(tib, self);
  
  #if notyet
  	/* mark the condvar as being associated with this mutex */
  	if (cond->mutex == NULL)
  		atomic_cas_ptr(&cond->mutex, NULL, mutex);
  
  	if (cond->mutex != mutex) {
  		LEAVE_CANCEL_POINT_INNER(tib, 1);
  		return (EINVAL);
  	}
  #endif
  
  	/* snag the count in case this is a recursive mutex */
  	if (mutex->type == PTHREAD_MUTEX_RECURSIVE)
  		mutex_count = mutex->count;
  
  	pthread_mutex_unlock(mutexp);
  
  	do {
  		/* If ``seq'' wraps you deserve to lose a signal. */
  		error = _twait(&cond->seq, seq, clock, abs);
  		/*
  		* If we took a normal signal (not from cancellation) then
  		* we should just go back to sleep without changing state
  		* (timeouts, etc).
  		*/
  	} while ((error == EINTR) &&
  	   (tib->tib_canceled == 0 || (tib->tib_cantcancel & CANCEL_DISABLED)));
  
  	/* if timeout or canceled, make note of that */
  	if (error == ETIMEDOUT)
  		rv = ETIMEDOUT;
  	else if (error == EINTR)
  		canceled = 1;
  
  	pthread_mutex_lock(mutexp);
  
  	/* restore the mutex's count */
  	if (mutex->type == PTHREAD_MUTEX_RECURSIVE)
  		mutex->count = mutex_count;
  
  	LEAVE_CANCEL_POINT_INNER(tib, canceled);
  
  	return rv;
  }
  
  int
  pthread_cond_timedwait(pthread_cond_t *condp, pthread_mutex_t *mutexp,
      const struct timespec *abs)
  {
  	pthread_cond_t cond;
  	int error;
  
  	if (*condp == NULL) {
  		if ((error = pthread_cond_init(condp, NULL)))
  			return (error);
  	}
  
  	cond = *condp;
  	if (abs == NULL || abs->tv_sec < 0 || abs->tv_nsec < 0 ||
  	    abs->tv_nsec >= 1000000000)
  		return (EINVAL);
  
  	return (_rthread_cond_timedwait(cond, mutexp, abs));
  }
  
  int
  pthread_cond_wait(pthread_cond_t *condp, pthread_mutex_t *mutexp)
  {
  	pthread_cond_t cond;
  	int error;
  
  	if (*condp == NULL) {
  		if ((error = pthread_cond_init(condp, NULL)))
  			return (error);
  	}
  
  	cond = *condp;
  	return (_rthread_cond_timedwait(cond, mutexp, NULL));
  }
  
  int
  pthread_cond_signal(pthread_cond_t *condp)
  {
  	pthread_cond_t cond;
  	int count;
  
  	if (*condp == NULL)
  		return (0);
  
  	cond = *condp;
  
  	atomic_inc_int(&cond->seq);
  	count = _wake(&cond->seq, 1);
  
  	_rthread_debug(5, "%p: cond_signal %p, %d awaken\n", pthread_self(),
  	    (void *)cond, count);
  
  	return (0);
  }
  
  int
  pthread_cond_broadcast(pthread_cond_t *condp)
  {
  	pthread_cond_t cond;
  	int count;
  
  	if (*condp == NULL)
  		return (0);
  
  	cond = *condp;
  
  	atomic_inc_int(&cond->seq);
  #if notyet
  	count = _requeue(&cond->seq, 1, INT_MAX, &cond->mutex->lock);
  #else
  	count = _wake(&cond->seq, INT_MAX);
  #endif
  
  	_rthread_debug(5, "%p: cond_broadcast %p, %d awaken\n", pthread_self(),
  	    (void *)cond, count);
  
  	return (0);
  }