htl/pt-cancel.c

   1 /* Cancel a thread.
   2    Copyright (C) 2002-2020 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 <pthread.h>
  20
  21 #include <pt-internal.h>
  22
  23 int
  24 pthread_cancel (pthread_t t)
  25 {
  26   int err = 0;
  27   struct __pthread *p;
  28
  29   p = __pthread_getid (t);
  30   if (p == NULL)
  31     return ESRCH;
  32
  33   __pthread_mutex_lock (&p->cancel_lock);
  34   if (p->cancel_pending)
  35     {
  36       __pthread_mutex_unlock (&p->cancel_lock);
  37       return 0;
  38     }
  39
  40   p->cancel_pending = 1;
  41
  42   if (p->cancel_state != PTHREAD_CANCEL_ENABLE)
  43     {
  44       __pthread_mutex_unlock (&p->cancel_lock);
  45       return 0;
  46     }
  47
  48   if (p->cancel_type == PTHREAD_CANCEL_ASYNCHRONOUS)
  49     /* CANCEL_LOCK is unlocked by this call.  */
  50     err = __pthread_do_cancel (p);
  51   else
  52     {
  53       if (p->cancel_hook != NULL)
  54         /* Thread blocking on a cancellation point.  Invoke hook to unblock.
  55            See __pthread_cond_timedwait_internal.  */
  56         p->cancel_hook (p->cancel_hook_arg);
  57
  58       __pthread_mutex_unlock (&p->cancel_lock);
  59     }
  60
  61   return err;
  62 }