nptl/libc-cleanup.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 "pthreadP.h"
  19 #include <tls.h>
  20 #include <libc-lock.h>
  21
  22 void
  23 __libc_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer)
  24 {
  25   struct pthread *self = THREAD_SELF;
  26
  27   buffer->__prev = THREAD_GETMEM (self, cleanup);
  28
  29   int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
  30
  31   /* Disable asynchronous cancellation for now.  */
  32   if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
  33     {
  34       int newval;
  35       do
  36         {
  37           newval = cancelhandling & ~CANCELTYPE_BITMASK;
  38         }
  39       while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
  40                                                     &cancelhandling,
  41                                                     newval));
  42     }
  43
  44   buffer->__canceltype = (cancelhandling & CANCELTYPE_BITMASK
  45                           ? PTHREAD_CANCEL_ASYNCHRONOUS
  46                           : PTHREAD_CANCEL_DEFERRED);
  47
  48   THREAD_SETMEM (self, cleanup, buffer);
  49 }
  50 libc_hidden_def (__libc_cleanup_push_defer)
  51
  52 void
  53 __libc_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer)
  54 {
  55   struct pthread *self = THREAD_SELF;
  56
  57   THREAD_SETMEM (self, cleanup, buffer->__prev);
  58
  59   int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
  60   if (buffer->__canceltype != PTHREAD_CANCEL_DEFERRED
  61       && (cancelhandling & CANCELTYPE_BITMASK) == 0)
  62     {
  63       int newval;
  64       do
  65         {
  66           newval = cancelhandling | CANCELTYPE_BITMASK;
  67         }
  68       while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
  69                                                     &cancelhandling, newval));
  70
  71       if (cancel_enabled_and_canceled (cancelhandling))
  72         {
  73           self->result = PTHREAD_CANCELED;
  74           __do_cancel ();
  75         }
  76     }
  77 }
  78 libc_hidden_def (__libc_cleanup_pop_restore)