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Diffstat (limited to 'nuttx/sched/pthread_completejoin.c')
| -rw-r--r-- | nuttx/sched/pthread_completejoin.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/nuttx/sched/pthread_completejoin.c b/nuttx/sched/pthread_completejoin.c new file mode 100644 index 0000000000..a5e7651e01 --- /dev/null +++ b/nuttx/sched/pthread_completejoin.c @@ -0,0 +1,211 @@ +/************************************************************ + * pthread_completejoin.c + * + * Copyright (C) 2007 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 Gregory Nutt 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 <sys/types.h> +#include <pthread.h> +#include <errno.h> +#include <debug.h> +#include "os_internal.h" +#include "pthread_internal.h" + +/************************************************************ + * Definitions + ************************************************************/ + +/************************************************************ + * Private Type Declarations + ************************************************************/ + +/************************************************************ + * Global Variables + ************************************************************/ + +/************************************************************ + * Private Variables + ************************************************************/ + +/************************************************************ + * Private Functions + ************************************************************/ + +/************************************************************ + * Function: pthread_destroyjoininfo + * + * Description: + * Destroy a join_t structure. This must + * be done by the child thread at child thread destruction + * time. + * + ************************************************************/ + +static void pthread_destroyjoininfo(join_t *pjoin) +{ + int ntasks_waiting; + int status; + + dbg("%s: pjoin=0x%p\n", __FUNCTION__, pjoin); + + /* Are any tasks waiting for our exit value? */ + + status = sem_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)sem_init(&pjoin->data_sem, 0, (ntasks_waiting+1)); + + /* Post the semaphore to restart each thread that is waiting + * on the semaphore + */ + + do + { + status = pthread_givesemaphore(&pjoin->exit_sem); + if (status == OK) + { + status = sem_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_takesemaphore(&pjoin->data_sem); + (void)sem_destroy(&pjoin->data_sem); + } + + /* All of the joined threads have had received the exit value. + * Now we can destroy this thread's exit semaphore + */ + + (void)sem_destroy(&pjoin->exit_sem); +} + +/************************************************************ + * Public Functions + ************************************************************/ + +/************************************************************ + * Function: 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. + * + * 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, void *exit_value) +{ + join_t *pjoin; + boolean detached = FALSE; + + dbg("%s: process_id=%d exit_value=%p\n", __FUNCTION__, pid, exit_value); + + /* First, find thread's structure in the private data set. */ + + (void)pthread_takesemaphore(&g_join_semaphore); + pjoin = pthread_findjoininfo(pid); + if (!pjoin) + { + + (void)pthread_givesemaphore(&g_join_semaphore); + return ERROR; + } + else + { + /* Has the thread been marked as detached? */ + + pjoin->terminated = TRUE; + detached = pjoin->detached; + if (detached) + { + dbg("%s: Detaching\n", __FUNCTION__); + + /* If so, then remove the thread's structure from the private + * data set. After this point, no other thread can perform a join + * operation. + */ + + (void)pthread_removejoininfo(pid); + (void)pthread_givesemaphore(&g_join_semaphore); + + /* Destroy this thread data structure. */ + + pthread_destroyjoininfo(pjoin); + + /* Deallocate the join entry if it was detached. */ + + sched_free((void*)pjoin); + } + + /* No, then we can assume that some other thread is waiting for the join info */ + + else + { + /* Save the return exit value in the thread structure. */ + + pjoin->exit_value = exit_value; + + /* Destroy this thread data structure. */ + + pthread_destroyjoininfo(pjoin); + + /* pthread_join may now access the thread entry structure. */ + + (void)pthread_givesemaphore(&g_join_semaphore); + } + } + + return OK; +} |