htl/pt-join.c

   1 /* Wait for thread termination.
   2    Copyright (C) 2000-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library;  if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <pthread.h>
  21 #include <stddef.h>
  22
  23 #include <pt-internal.h>
  24
  25 /* Make calling thread wait for termination of thread THREAD.  Return
  26    the exit status of the thread in *STATUS.  */
  27 int
  28 pthread_join (pthread_t thread, void **status)
  29 {
  30   struct __pthread *pthread;
  31   int err = 0;
  32
  33   /* Lookup the thread structure for THREAD.  */
  34   pthread = __pthread_getid (thread);
  35   if (pthread == NULL)
  36     return ESRCH;
  37
  38   __pthread_mutex_lock (&pthread->state_lock);
  39   pthread_cleanup_push ((void (*)(void *)) __pthread_mutex_unlock,
  40                         &pthread->state_lock);
  41
  42   /* Rely on pthread_cond_wait being a cancellation point to make
  43      pthread_join one too.  */
  44   while (pthread->state == PTHREAD_JOINABLE)
  45     __pthread_cond_wait (&pthread->state_cond, &pthread->state_lock);
  46
  47   pthread_cleanup_pop (0);
  48
  49   switch (pthread->state)
  50     {
  51     case PTHREAD_EXITED:
  52       /* THREAD has already exited.  Salvage its exit status.  */
  53       if (status != NULL)
  54         *status = pthread->status;
  55
  56       __pthread_mutex_unlock (&pthread->state_lock);
  57
  58       __pthread_dealloc (pthread);
  59       break;
  60
  61     case PTHREAD_TERMINATED:
  62       /* Pretend THREAD wasn't there in the first place.  */
  63       __pthread_mutex_unlock (&pthread->state_lock);
  64       err = ESRCH;
  65       break;
  66
  67     default:
  68       /* Thou shalt not join non-joinable threads!  */
  69       __pthread_mutex_unlock (&pthread->state_lock);
  70       err = EINVAL;
  71       break;
  72     }
  73
  74   return err;
  75 }