123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289 |
- /****************************************************************************
- * sched/pthread/pthread_completejoin.c
- *
- * Copyright (C) 2007, 2009, 2011, 2013 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * 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. Neither the name NuttX 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 COPYRIGHT HOLDERS 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
- * COPYRIGHT OWNER 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.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <sys/types.h>
- #include <stdbool.h>
- #include <pthread.h>
- #include <errno.h>
- #include <debug.h>
- #include "sched/sched.h"
- #include "group/group.h"
- #include "pthread/pthread.h"
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: pthread_notifywaiters
- *
- * Description:
- * Notify all other threads waiting in phread join for this thread's
- * exit data. This must be done by the child at child thread
- * destruction time.
- *
- ****************************************************************************/
- static bool pthread_notifywaiters(FAR struct join_s *pjoin)
- {
- int ntasks_waiting;
- int status;
- sinfo("pjoin=0x%p\n", pjoin);
- /* Are any tasks waiting for our exit value? */
- status = nxsem_getvalue(&pjoin->exit_sem, &ntasks_waiting);
- if (status == OK && ntasks_waiting < 0)
- {
- /* Set the data semaphore so that this thread will be
- * awakened when all waiting tasks receive the data
- */
- (void)nxsem_init(&pjoin->data_sem, 0, (ntasks_waiting + 1));
- /* Post the semaphore to restart each thread that is waiting
- * on the semaphore
- */
- do
- {
- status = pthread_sem_give(&pjoin->exit_sem);
- if (status == OK)
- {
- status = nxsem_getvalue(&pjoin->exit_sem, &ntasks_waiting);
- }
- }
- while (ntasks_waiting < 0 && status == OK);
- /* Now wait for all these restarted tasks to obtain the return
- * value.
- */
- (void)pthread_sem_take(&pjoin->data_sem, false);
- return true;
- }
- return false;
- }
- /****************************************************************************
- * Name: pthread_removejoininfo
- *
- * Description:
- * Remove a join structure from the local data set.
- *
- * Input Parameters:
- * pid
- *
- * Returned Value:
- * None.
- *
- * Assumptions:
- * The caller has provided protection from re-entrancy.
- *
- ****************************************************************************/
- static void pthread_removejoininfo(FAR struct task_group_s *group,
- pid_t pid)
- {
- FAR struct join_s *prev;
- FAR struct join_s *join;
- /* Find the entry with the matching pid */
- for (prev = NULL, join = group->tg_joinhead;
- (join && (pid_t)join->thread != pid);
- prev = join, join = join->next);
- /* Remove it from the data set. */
- /* First check if this is the entry at the head of the list. */
- if (join)
- {
- if (!prev)
- {
- /* Check if this is the only entry in the list */
- if (!join->next)
- {
- group->tg_joinhead = NULL;
- group->tg_jointail = NULL;
- }
- /* Otherwise, remove it from the head of the list */
- else
- {
- group->tg_joinhead = join->next;
- }
- }
- /* It is not at the head of the list, check if it is at the tail. */
- else if (!join->next)
- {
- group->tg_jointail = prev;
- prev->next = NULL;
- }
- /* No, remove it from the middle of the list. */
- else
- {
- prev->next = join->next;
- }
- }
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: pthread_completejoin
- *
- * Description:
- * A thread has been terminated -- either by returning, calling
- * pthread_exit(), or through pthread_cancel(). In any event, we must
- * complete any pending join events.
- *
- * Input Parameters:
- * exit_value
- *
- * Returned Value:
- * OK unless there is no join information associated with the pid.
- * This could happen, for example, if a task started with task_create()
- * calls pthread_exit().
- *
- * Assumptions:
- *
- ****************************************************************************/
- int pthread_completejoin(pid_t pid, FAR void *exit_value)
- {
- FAR struct task_group_s *group = task_getgroup(pid);
- FAR struct join_s *pjoin;
- sinfo("pid=%d exit_value=%p group=%p\n", pid, exit_value, group);
- DEBUGASSERT(group);
- /* First, find thread's structure in the private data set. */
- (void)pthread_sem_take(&group->tg_joinsem, false);
- pjoin = pthread_findjoininfo(group, pid);
- if (!pjoin)
- {
- serr("ERROR: Could not find join info, pid=%d\n", pid);
- (void)pthread_sem_give(&group->tg_joinsem);
- return ERROR;
- }
- else
- {
- bool waiters;
- /* Save the return exit value in the thread structure. */
- pjoin->terminated = true;
- pjoin->exit_value = exit_value;
- /* Notify waiters of the availability of the exit value */
- waiters = pthread_notifywaiters(pjoin);
- /* If there are no waiters and if the thread is marked as detached.
- * then discard the join information now. Otherwise, the pthread
- * join logic will call pthread_destroyjoin() when all of the threads
- * have sampled the exit value.
- */
- if (!waiters && pjoin->detached)
- {
- pthread_destroyjoin(group, pjoin);
- }
- /* Giving the following semaphore will allow the waiters
- * to call pthread_destroyjoin.
- */
- (void)pthread_sem_give(&group->tg_joinsem);
- }
- return OK;
- }
- /****************************************************************************
- * Name: pthread_destroyjoin
- *
- * Description:
- * This is called from pthread_completejoin if the join info was
- * detached or from pthread_join when the last waiting thread has
- * received the thread exit info.
- *
- * Or it may never be called if the join info was never detached or if
- * no thread ever calls pthread_join. In case, there is a memory leak!
- *
- * Assumptions:
- * The caller holds tg_joinsem
- *
- ****************************************************************************/
- void pthread_destroyjoin(FAR struct task_group_s *group,
- FAR struct join_s *pjoin)
- {
- sinfo("pjoin=0x%p\n", pjoin);
- /* Remove the join info from the set of joins */
- pthread_removejoininfo(group, (pid_t)pjoin->thread);
- /* Destroy its semaphores */
- (void)nxsem_destroy(&pjoin->data_sem);
- (void)nxsem_destroy(&pjoin->exit_sem);
- /* And deallocate the pjoin structure */
- sched_kfree(pjoin);
- }
|