nptl/cleanup_defer_compat.c

   1 /* Copyright (C) 2002-2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include "pthreadP.h"
  20
  21
  22 void
  23 _pthread_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer,
  24                              void (*routine) (void *), void *arg)
  25 {
  26   struct pthread *self = THREAD_SELF;
  27
  28   buffer->__routine = routine;
  29   buffer->__arg = arg;
  30   buffer->__prev = THREAD_GETMEM (self, cleanup);
  31
  32   int cancelhandling = THREAD_GETMEM (self, cancelhandling);
  33
  34   /* Disable asynchronous cancellation for now.  */
  35   if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
  36     while (1)
  37       {
  38         int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
  39                                                 cancelhandling
  40                                                 & ~CANCELTYPE_BITMASK,
  41                                                 cancelhandling);
  42         if (__glibc_likely (curval == cancelhandling))
  43           /* Successfully replaced the value.  */
  44           break;
  45
  46         /* Prepare for the next round.  */
  47         cancelhandling = curval;
  48       }
  49
  50   buffer->__canceltype = (cancelhandling & CANCELTYPE_BITMASK
  51                           ? PTHREAD_CANCEL_ASYNCHRONOUS
  52                           : PTHREAD_CANCEL_DEFERRED);
  53
  54   THREAD_SETMEM (self, cleanup, buffer);
  55 }
  56 strong_alias (_pthread_cleanup_push_defer, __pthread_cleanup_push_defer)
  57
  58
  59 void
  60 _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer,
  61                               int execute)
  62 {
  63   struct pthread *self = THREAD_SELF;
  64
  65   THREAD_SETMEM (self, cleanup, buffer->__prev);
  66
  67   int cancelhandling;
  68   if (__builtin_expect (buffer->__canceltype != PTHREAD_CANCEL_DEFERRED, 0)
  69       && ((cancelhandling = THREAD_GETMEM (self, cancelhandling))
  70           & CANCELTYPE_BITMASK) == 0)
  71     {
  72       while (1)
  73         {
  74           int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
  75                                                   cancelhandling
  76                                                   | CANCELTYPE_BITMASK,
  77                                                   cancelhandling);
  78           if (__glibc_likely (curval == cancelhandling))
  79             /* Successfully replaced the value.  */
  80             break;
  81
  82           /* Prepare for the next round.  */
  83           cancelhandling = curval;
  84         }
  85
  86       CANCELLATION_P (self);
  87     }
  88
  89   /* If necessary call the cleanup routine after we removed the
  90      current cleanup block from the list.  */
  91   if (execute)
  92     buffer->__routine (buffer->__arg);
  93 }
  94 strong_alias (_pthread_cleanup_pop_restore, __pthread_cleanup_pop_restore)