nptl/cancellation.c

   1 /* Copyright (C) 2002-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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 <setjmp.h>
  20 #include <stdlib.h>
  21 #include "pthreadP.h"
  22 #include <futex-internal.h>
  23
  24
  25 /* The next two functions are similar to pthread_setcanceltype() but
  26    more specialized for the use in the cancelable functions like write().
  27    They do not need to check parameters etc.  These functions must be
  28    AS-safe, with the exception of the actual cancellation, because they
  29    are called by wrappers around AS-safe functions like write().*/
  30 int
  31 __pthread_enable_asynccancel (void)
  32 {
  33   struct pthread *self = THREAD_SELF;
  34
  35   int oldval = THREAD_GETMEM (self, canceltype);
  36   THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_ASYNCHRONOUS);
  37
  38   int ch = THREAD_GETMEM (self, cancelhandling);
  39
  40   if (self->cancelstate == PTHREAD_CANCEL_ENABLE
  41       && (ch & CANCELED_BITMASK)
  42       && !(ch & EXITING_BITMASK)
  43       && !(ch & TERMINATED_BITMASK))
  44     {
  45       THREAD_SETMEM (self, result, PTHREAD_CANCELED);
  46       __do_cancel ();
  47     }
  48
  49   return oldval;
  50 }
  51 libc_hidden_def (__pthread_enable_asynccancel)
  52
  53 /* See the comment for __pthread_enable_asynccancel regarding
  54    the AS-safety of this function.  */
  55 void
  56 __pthread_disable_asynccancel (int oldtype)
  57 {
  58   /* If asynchronous cancellation was enabled before we do not have
  59      anything to do.  */
  60   if (oldtype == PTHREAD_CANCEL_ASYNCHRONOUS)
  61     return;
  62
  63   struct pthread *self = THREAD_SELF;
  64   self->canceltype = PTHREAD_CANCEL_DEFERRED;
  65 }
  66 libc_hidden_def (__pthread_disable_asynccancel)