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 1.2 2005/03/29 19:26:20 joerg Exp $
  27  */
  28
  29 #include <machine/tls.h>
  30
  31 #include <pthread.h>
  32 #include "thr_private.h"
  33
  34 __weak_reference(_pthread_cancel, pthread_cancel);
  35 __weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
  36 __weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
  37 __weak_reference(_pthread_testcancel, pthread_testcancel);
  38
  39 int _pthread_setcanceltype(int type, int *oldtype);
  40
  41 int
  42 _pthread_cancel(pthread_t pthread)
  43 {
  44         struct pthread *curthread = tls_get_curthread();
  45         int oldval, newval = 0;
  46         int oldtype;
  47         int ret;
  48
  49         /*
  50          * POSIX says _pthread_cancel should be async cancellation safe,
  51          * so we temporarily disable async cancellation.
  52          */
  53         _pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
  54         if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
  55                 _pthread_setcanceltype(oldtype, NULL);
  56                 return (ret);
  57         }
  58
  59         do {
  60                 oldval = pthread->cancelflags;
  61                 if (oldval & THR_CANCEL_NEEDED)
  62                         break;
  63                 newval = oldval | THR_CANCEL_NEEDED;
  64         } while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
  65
  66         if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
  67                 _thr_send_sig(pthread, SIGCANCEL);
  68
  69         _thr_ref_delete(curthread, pthread);
  70         _pthread_setcanceltype(oldtype, NULL);
  71         return (0);
  72 }
  73
  74 static inline void
  75 testcancel(struct pthread *curthread)
  76 {
  77         int newval;
  78
  79         newval = curthread->cancelflags;
  80         if (SHOULD_CANCEL(newval))
  81                 pthread_exit(PTHREAD_CANCELED);
  82 }
  83
  84 int
  85 _pthread_setcancelstate(int state, int *oldstate)
  86 {
  87         struct pthread *curthread = tls_get_curthread();
  88         int oldval, ret;
  89
  90         oldval = curthread->cancelflags;
  91         if (oldstate != NULL)
  92                 *oldstate = ((oldval & THR_CANCEL_DISABLE) ?
  93                     PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
  94         switch (state) {
  95         case PTHREAD_CANCEL_DISABLE:
  96                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
  97                 ret = 0;
  98                 break;
  99         case PTHREAD_CANCEL_ENABLE:
 100                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
 101                 testcancel(curthread);
 102                 ret = 0;
 103                 break;
 104         default:
 105                 ret = EINVAL;
 106         }
 107
 108         return (ret);
 109 }
 110
 111 int
 112 _pthread_setcanceltype(int type, int *oldtype)
 113 {
 114         struct pthread  *curthread = tls_get_curthread();
 115         int oldval, ret;
 116
 117         oldval = curthread->cancelflags;
 118         if (oldtype != NULL)
 119                 *oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
 120                                  PTHREAD_CANCEL_ASYNCHRONOUS :
 121                                  PTHREAD_CANCEL_DEFERRED);
 122         switch (type) {
 123         case PTHREAD_CANCEL_ASYNCHRONOUS:
 124                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 125                 testcancel(curthread);
 126                 ret = 0;
 127                 break;
 128         case PTHREAD_CANCEL_DEFERRED:
 129                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 130                 ret = 0;
 131                 break;
 132         default:
 133                 ret = EINVAL;
 134         }
 135
 136         return (ret);
 137 }
 138
 139 void
 140 _pthread_testcancel(void)
 141 {
 142         testcancel(tls_get_curthread());
 143 }
 144
 145 int
 146 _thr_cancel_enter(struct pthread *curthread)
 147 {
 148         int oldval;
 149
 150         oldval = curthread->cancelflags;
 151         if (!(oldval & THR_CANCEL_AT_POINT)) {
 152                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 153                 testcancel(curthread);
 154         }
 155         return (oldval);
 156 }
 157
 158 void
 159 _thr_cancel_leave(struct pthread *curthread, int previous)
 160 {
 161         if (!(previous & THR_CANCEL_AT_POINT))
 162                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 163 }