libpthread/nptl/cleanup_defer.c

   1 /* Copyright (C) 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stdlib.h>
  21 #include "pthreadP.h"
  22
  23
  24 void
  25 __cleanup_fct_attribute
  26 __pthread_register_cancel_defer (__pthread_unwind_buf_t *buf)
  27 {
  28   struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
  29   struct pthread *self = THREAD_SELF;
  30
  31   /* Store old info.  */
  32   ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
  33   ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup);
  34
  35   int cancelhandling = THREAD_GETMEM (self, cancelhandling);
  36
  37   /* Disable asynchronous cancellation for now.  */
  38   if (__builtin_expect (cancelhandling & CANCELTYPE_BITMASK, 0))
  39     while (1)
  40       {
  41         int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
  42                                                 cancelhandling
  43                                                 & ~CANCELTYPE_BITMASK,
  44                                                 cancelhandling);
  45         if (__builtin_expect (curval == cancelhandling, 1))
  46           /* Successfully replaced the value.  */
  47           break;
  48
  49         /* Prepare for the next round.  */
  50         cancelhandling = curval;
  51       }
  52
  53   ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK
  54                                 ? PTHREAD_CANCEL_ASYNCHRONOUS
  55                                 : PTHREAD_CANCEL_DEFERRED);
  56
  57   /* Store the new cleanup handler info.  */
  58   THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf);
  59 }
  60
  61
  62 void
  63 __cleanup_fct_attribute
  64 __pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf)
  65 {
  66   struct pthread *self = THREAD_SELF;
  67   struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
  68
  69   THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev);
  70
  71   int cancelhandling;
  72   if (ibuf->priv.data.canceltype != PTHREAD_CANCEL_DEFERRED
  73       && ((cancelhandling = THREAD_GETMEM (self, cancelhandling))
  74           & CANCELTYPE_BITMASK) == 0)
  75     {
  76       while (1)
  77         {
  78           int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
  79                                                   cancelhandling
  80                                                   | CANCELTYPE_BITMASK,
  81                                                   cancelhandling);
  82           if (__builtin_expect (curval == cancelhandling, 1))
  83             /* Successfully replaced the value.  */
  84             break;
  85
  86           /* Prepare for the next round.  */
  87           cancelhandling = curval;
  88         }
  89
  90       CANCELLATION_P (self);
  91     }
  92 }