lib/libthread_xu/thread/thr_cancel.c

   1 /*
   2  * Copyright (c) 2005, David Xu<davidxu@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $DragonFly: src/lib/libthread_xu/thread/thr_cancel.c,v 1.1 2005/02/01 12:38:27 davidxu Exp $
  27  */
  28
  29 #include <pthread.h>
  30 #include "thr_private.h"
  31
  32 __weak_reference(_pthread_cancel, pthread_cancel);
  33 __weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
  34 __weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
  35 __weak_reference(_pthread_testcancel, pthread_testcancel);
  36
  37 int _pthread_setcanceltype(int type, int *oldtype);
  38
  39 int
  40 _pthread_cancel(pthread_t pthread)
  41 {
  42         struct pthread *curthread = _get_curthread();
  43         int oldval, newval = 0;
  44         int oldtype;
  45         int ret;
  46
  47         /*
  48          * POSIX says _pthread_cancel should be async cancellation safe,
  49          * so we temporarily disable async cancellation.
  50          */
  51         _pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
  52         if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
  53                 _pthread_setcanceltype(oldtype, NULL);
  54                 return (ret);
  55         }
  56
  57         do {
  58                 oldval = pthread->cancelflags;
  59                 if (oldval & THR_CANCEL_NEEDED)
  60                         break;
  61                 newval = oldval | THR_CANCEL_NEEDED;
  62         } while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
  63
  64         if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
  65                 _thr_send_sig(pthread, SIGCANCEL);
  66
  67         _thr_ref_delete(curthread, pthread);
  68         _pthread_setcanceltype(oldtype, NULL);
  69         return (0);
  70 }
  71
  72 static inline void
  73 testcancel(struct pthread *curthread)
  74 {
  75         int newval;
  76
  77         newval = curthread->cancelflags;
  78         if (SHOULD_CANCEL(newval))
  79                 pthread_exit(PTHREAD_CANCELED);
  80 }
  81
  82 int
  83 _pthread_setcancelstate(int state, int *oldstate)
  84 {
  85         struct pthread *curthread = _get_curthread();
  86         int oldval, ret;
  87
  88         oldval = curthread->cancelflags;
  89         if (oldstate != NULL)
  90                 *oldstate = ((oldval & THR_CANCEL_DISABLE) ?
  91                     PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
  92         switch (state) {
  93         case PTHREAD_CANCEL_DISABLE:
  94                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
  95                 ret = 0;
  96                 break;
  97         case PTHREAD_CANCEL_ENABLE:
  98                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
  99                 testcancel(curthread);
 100                 ret = 0;
 101                 break;
 102         default:
 103                 ret = EINVAL;
 104         }
 105
 106         return (ret);
 107 }
 108
 109 int
 110 _pthread_setcanceltype(int type, int *oldtype)
 111 {
 112         struct pthread  *curthread = _get_curthread();
 113         int oldval, ret;
 114
 115         oldval = curthread->cancelflags;
 116         if (oldtype != NULL)
 117                 *oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
 118                                  PTHREAD_CANCEL_ASYNCHRONOUS :
 119                                  PTHREAD_CANCEL_DEFERRED);
 120         switch (type) {
 121         case PTHREAD_CANCEL_ASYNCHRONOUS:
 122                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 123                 testcancel(curthread);
 124                 ret = 0;
 125                 break;
 126         case PTHREAD_CANCEL_DEFERRED:
 127                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 128                 ret = 0;
 129                 break;
 130         default:
 131                 ret = EINVAL;
 132         }
 133
 134         return (ret);
 135 }
 136
 137 void
 138 _pthread_testcancel(void)
 139 {
 140         testcancel(_get_curthread());
 141 }
 142
 143 int
 144 _thr_cancel_enter(struct pthread *curthread)
 145 {
 146         int oldval;
 147
 148         oldval = curthread->cancelflags;
 149         if (!(oldval & THR_CANCEL_AT_POINT)) {
 150                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 151                 testcancel(curthread);
 152         }
 153         return (oldval);
 154 }
 155
 156 void
 157 _thr_cancel_leave(struct pthread *curthread, int previous)
 158 {
 159         if (!(previous & THR_CANCEL_AT_POINT))
 160                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 161 }