htl/pt-join.c

   1 /* Wait for thread termination.
   2    Copyright (C) 2000-2019 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 #define __pthread_get_cleanup_stack ___pthread_get_cleanup_stack
  26
  27 /* Make calling thread wait for termination of thread THREAD.  Return
  28    the exit status of the thread in *STATUS.  */
  29 int
  30 pthread_join (pthread_t thread, void **status)
  31 {
  32   struct __pthread *pthread;
  33   int err = 0;
  34
  35   /* Lookup the thread structure for THREAD.  */
  36   pthread = __pthread_getid (thread);
  37   if (pthread == NULL)
  38     return ESRCH;
  39
  40   __pthread_mutex_lock (&pthread->state_lock);
  41   pthread_cleanup_push ((void (*)(void *)) __pthread_mutex_unlock,
  42                         &pthread->state_lock);
  43
  44   /* Rely on pthread_cond_wait being a cancellation point to make
  45      pthread_join one too.  */
  46   while (pthread->state == PTHREAD_JOINABLE)
  47     __pthread_cond_wait (&pthread->state_cond, &pthread->state_lock);
  48
  49   pthread_cleanup_pop (0);
  50
  51   switch (pthread->state)
  52     {
  53     case PTHREAD_EXITED:
  54       /* THREAD has already exited.  Salvage its exit status.  */
  55       if (status != NULL)
  56         *status = pthread->status;
  57
  58       __pthread_mutex_unlock (&pthread->state_lock);
  59
  60       __pthread_dealloc (pthread);
  61       break;
  62
  63     case PTHREAD_TERMINATED:
  64       /* Pretend THREAD wasn't there in the first place.  */
  65       __pthread_mutex_unlock (&pthread->state_lock);
  66       err = ESRCH;
  67       break;
  68
  69     default:
  70       /* Thou shalt not join non-joinable threads!  */
  71       __pthread_mutex_unlock (&pthread->state_lock);
  72       err = EINVAL;
  73       break;
  74     }
  75
  76   return err;
  77 }