nptl/cancellation.c

   1 /* Copyright (C) 2002-2022 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <setjmp.h>
  19 #include <stdlib.h>
  20 #include "pthreadP.h"
  21 #include <futex-internal.h>
  22
  23
  24 /* The next two functions are similar to pthread_setcanceltype() but
  25    more specialized for the use in the cancelable functions like write().
  26    They do not need to check parameters etc.  These functions must be
  27    AS-safe, with the exception of the actual cancellation, because they
  28    are called by wrappers around AS-safe functions like write().*/
  29 int
  30 __pthread_enable_asynccancel (void)
  31 {
  32   struct pthread *self = THREAD_SELF;
  33
  34   int oldval = THREAD_GETMEM (self, canceltype);
  35   THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_ASYNCHRONOUS);
  36
  37   int ch = THREAD_GETMEM (self, cancelhandling);
  38
  39   if (self->cancelstate == PTHREAD_CANCEL_ENABLE
  40       && (ch & CANCELED_BITMASK)
  41       && !(ch & EXITING_BITMASK)
  42       && !(ch & TERMINATED_BITMASK))
  43     {
  44       THREAD_SETMEM (self, result, PTHREAD_CANCELED);
  45       __do_cancel ();
  46     }
  47
  48   return oldval;
  49 }
  50 libc_hidden_def (__pthread_enable_asynccancel)
  51
  52 /* See the comment for __pthread_enable_asynccancel regarding
  53    the AS-safety of this function.  */
  54 void
  55 __pthread_disable_asynccancel (int oldtype)
  56 {
  57   /* If asynchronous cancellation was enabled before we do not have
  58      anything to do.  */
  59   if (oldtype == PTHREAD_CANCEL_ASYNCHRONOUS)
  60     return;
  61
  62   struct pthread *self = THREAD_SELF;
  63   self->canceltype = PTHREAD_CANCEL_DEFERRED;
  64 }
  65 libc_hidden_def (__pthread_disable_asynccancel)