htl/pt-exit.c

   1 /* Thread termination.
   2    Copyright (C) 2000-2022 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <errno.h>
  21 #include <pthread.h>
  22 #include <stdlib.h>
  23
  24 #include <pt-internal.h>
  25 #include <pthreadP.h>
  26
  27 #include <atomic.h>
  28
  29
  30 /* Terminate the current thread and make STATUS available to any
  31    thread that might join it.  */
  32 void
  33 __pthread_exit (void *status)
  34 {
  35   struct __pthread *self = _pthread_self ();
  36   struct __pthread_cancelation_handler **handlers;
  37   int oldstate;
  38
  39   /* Run any cancelation handlers.  According to POSIX, the
  40      cancellation cleanup handlers should be called with cancellation
  41      disabled.  */
  42   __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
  43
  44   for (handlers = __pthread_get_cleanup_stack ();
  45        *handlers != NULL;
  46        *handlers = (*handlers)->__next)
  47     (*handlers)->__handler ((*handlers)->__arg);
  48
  49   __pthread_setcancelstate (oldstate, &oldstate);
  50
  51   /* Decrease the number of threads.  We use an atomic operation to
  52      make sure that only the last thread calls `exit'.  */
  53   if (atomic_fetch_add_relaxed (&__pthread_total, -1) == 1)
  54     /* We are the last thread.  */
  55     exit (0);
  56
  57   /* Destroy any thread specific data.  */
  58   __pthread_destroy_specific (self);
  59
  60   /* Note that after this point the process can be terminated at any
  61      point if another thread calls `pthread_exit' and happens to be
  62      the last thread.  */
  63
  64   __pthread_mutex_lock (&self->state_lock);
  65
  66   if (self->cancel_state == PTHREAD_CANCEL_ENABLE && self->cancel_pending)
  67     status = PTHREAD_CANCELED;
  68
  69   switch (self->state)
  70     {
  71     default:
  72       assert (!"Consistency error: unexpected self->state");
  73       abort ();
  74       break;
  75
  76     case PTHREAD_DETACHED:
  77       __pthread_mutex_unlock (&self->state_lock);
  78
  79       break;
  80
  81     case PTHREAD_JOINABLE:
  82       /* We need to stay around for a while since another thread
  83          might want to join us.  */
  84       self->state = PTHREAD_EXITED;
  85
  86       /* We need to remember the exit status.  A thread joining us
  87          might ask for it.  */
  88       self->status = status;
  89
  90       /* Broadcast the condition.  This will wake up threads that are
  91          waiting to join us.  */
  92       __pthread_cond_broadcast (&self->state_cond);
  93       __pthread_mutex_unlock (&self->state_lock);
  94
  95       break;
  96     }
  97
  98   /* Destroy any signal state.  */
  99   __pthread_sigstate_destroy (self);
 100
 101   /* Self terminating requires TLS, so defer the release of the TCB until
 102      the thread structure is reused.  */
 103
 104   /* Release kernel resources, including the kernel thread and the stack,
 105      and drop the self reference.  */
 106   __pthread_thread_terminate (self);
 107
 108   /* NOTREACHED */
 109   abort ();
 110 }
 111
 112 weak_alias (__pthread_exit, pthread_exit);