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/* Linuxthreads - a simple clone()-based implementation of Posix        */

/* threads for Linux.                                                   */

/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */

/*                                                                      */

/* This program is free software; you can redistribute it and/or        */

/* modify it under the terms of the GNU Library General Public License  */

/* as published by the Free Software Foundation; either version 2       */

/* of the License, or (at your option) any later version.               */

/*                                                                      */

/* This program is distributed in the hope that it will be useful,      */

/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */

/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */

/* GNU Library General Public License for more details.                 */

/* Thread termination and joining */

#include <errno.h>

#include <sched.h>

#include <stdlib.h>

#include <unistd.h>

#include "pthread.h"

#include "internals.h"

#include "spinlock.h"

#include "restart.h"

void pthread_exit(void * retval)

{

  __pthread_do_exit (retval, CURRENT_STACK_FRAME);

}

void __pthread_do_exit(void *retval, char *currentframe)

{

  pthread_descr self = thread_self();

  pthread_descr joining;

  struct pthread_request request;

  /* Reset the cancellation flag to avoid looping if the cleanup handlers

     contain cancellation points */

  THREAD_SETMEM(self, p_canceled, 0);

  /* Call cleanup functions and destroy the thread-specific data */

  __pthread_perform_cleanup(currentframe);

  __pthread_destroy_specifics();

  /* Store return value */

  __pthread_lock(THREAD_GETMEM(self, p_lock), self);

  THREAD_SETMEM(self, p_retval, retval);

  /* See whether we have to signal the death.  */

  if (THREAD_GETMEM(self, p_report_events))

    {

      /* See whether TD_DEATH is in any of the mask.  */

      int idx = __td_eventword (TD_DEATH);

      uint32_t mask = __td_eventmask (TD_DEATH);

      if ((mask & (__pthread_threads_events.event_bits[idx]

                   | THREAD_GETMEM_NC(self,

                                      p_eventbuf.eventmask.event_bits[idx])))

          != 0)

        {

          /* Yep, we have to signal the death.  */

          THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH);

          THREAD_SETMEM(self, p_eventbuf.eventdata, self);

          __pthread_last_event = self;

          /* Now call the function to signal the event.  */

          __linuxthreads_death_event();

        }

    }

  /* Say that we've terminated */

  THREAD_SETMEM(self, p_terminated, 1);

  /* See if someone is joining on us */

  joining = THREAD_GETMEM(self, p_joining);

  __pthread_unlock(THREAD_GETMEM(self, p_lock));

  /* Restart joining thread if any */

  if (joining != NULL) restart(joining);

  /* If this is the initial thread, block until all threads have terminated.

     If another thread calls exit, we'll be terminated from our signal

     handler. */

  if (self == __pthread_main_thread && __pthread_manager_request >= 0) {

    request.req_thread = self;

    request.req_kind = REQ_MAIN_THREAD_EXIT;

    TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,

                                    (char *)&request, sizeof(request)));

    suspend(self);

    /* Main thread flushes stdio streams and runs atexit functions.

       It also calls a handler within LinuxThreads which sends a process exit

       request to the thread manager. */

    exit(0);

  }

  /* Threads other than the main one  terminate without flushing stdio streams

     or running atexit functions. */

  _exit(0);

}

/* Function called by pthread_cancel to remove the thread from

   waiting on a condition variable queue. */

static int join_extricate_func(void *obj, pthread_descr th)

{

  volatile pthread_descr self = thread_self();

  pthread_handle handle = obj;

  pthread_descr jo;

  int did_remove = 0;

  __pthread_lock(&handle->h_lock, self);

  jo = handle->h_descr;

  did_remove = jo->p_joining != NULL;

  jo->p_joining = NULL;

  __pthread_unlock(&handle->h_lock);

  return did_remove;

}

int pthread_join(pthread_t thread_id, void ** thread_return)

{

  volatile pthread_descr self = thread_self();

  struct pthread_request request;

  pthread_handle handle = thread_handle(thread_id);

  pthread_descr th;

  pthread_extricate_if extr;

  int already_canceled = 0;

  /* Set up extrication interface */

  extr.pu_object = handle;

  extr.pu_extricate_func = join_extricate_func;

  __pthread_lock(&handle->h_lock, self);

  if (nonexisting_handle(handle, thread_id)) {

    __pthread_unlock(&handle->h_lock);

    return ESRCH;

  }

  th = handle->h_descr;

  if (th == self) {

    __pthread_unlock(&handle->h_lock);

    return EDEADLK;

  }

  /* If detached or already joined, error */

  if (th->p_detached || th->p_joining != NULL) {

    __pthread_unlock(&handle->h_lock);

    return EINVAL;

  }

  /* If not terminated yet, suspend ourselves. */

  if (! th->p_terminated) {

    /* Register extrication interface */

    __pthread_set_own_extricate_if(self, &extr);

    if (!(THREAD_GETMEM(self, p_canceled)

        && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))

      th->p_joining = self;

    else

      already_canceled = 1;

    __pthread_unlock(&handle->h_lock);

    if (already_canceled) {

      __pthread_set_own_extricate_if(self, 0);

      __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);

    }

    suspend(self);

    /* Deregister extrication interface */

    __pthread_set_own_extricate_if(self, 0);

    /* This is a cancellation point */

    if (THREAD_GETMEM(self, p_woken_by_cancel)

        && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {

      THREAD_SETMEM(self, p_woken_by_cancel, 0);

      __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);

    }

    __pthread_lock(&handle->h_lock, self);

  }

  /* Get return value */

  if (thread_return != NULL) *thread_return = th->p_retval;

  __pthread_unlock(&handle->h_lock);

  /* Send notification to thread manager */

  if (__pthread_manager_request >= 0) {

    request.req_thread = self;

    request.req_kind = REQ_FREE;

    request.req_args.free.thread_id = thread_id;

    TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,

                                    (char *) &request, sizeof(request)));

  }

  return 0;

}

int pthread_detach(pthread_t thread_id)

{

  int terminated;

  struct pthread_request request;

  pthread_handle handle = thread_handle(thread_id);

  pthread_descr th;

  __pthread_lock(&handle->h_lock, NULL);

  if (nonexisting_handle(handle, thread_id)) {

    __pthread_unlock(&handle->h_lock);

    return ESRCH;

  }

  th = handle->h_descr;

  /* If already detached, error */

  if (th->p_detached) {

    __pthread_unlock(&handle->h_lock);

    return EINVAL;

  }

  /* If already joining, don't do anything. */

  if (th->p_joining != NULL) {

    __pthread_unlock(&handle->h_lock);

    return 0;

  }

  /* Mark as detached */

  th->p_detached = 1;

  terminated = th->p_terminated;

  __pthread_unlock(&handle->h_lock);

  /* If already terminated, notify thread manager to reclaim resources */

  if (terminated && __pthread_manager_request >= 0) {

    request.req_thread = thread_self();

    request.req_kind = REQ_FREE;

    request.req_args.free.thread_id = thread_id;

    TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,

                                    (char *) &request, sizeof(request)));

  }

  return 0;

}