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 1.4 2006/04/06 13:03:09 davidxu Exp $
  27  */
  28
  29 #include "namespace.h"
  30 #include <machine/tls.h>
  31 #include <pthread.h>
  32 #include "un-namespace.h"
  33
  34 #include "thr_private.h"
  35
  36 int _pthread_setcanceltype(int type, int *oldtype);
  37
  38 int
  39 _pthread_cancel(pthread_t pthread)
  40 {
  41         struct pthread *curthread = tls_get_curthread();
  42         int oldval, newval = 0;
  43         int oldtype;
  44         int ret;
  45
  46         /*
  47          * POSIX says _pthread_cancel should be async cancellation safe,
  48          * so we temporarily disable async cancellation.
  49          */
  50         _pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
  51         if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
  52                 _pthread_setcanceltype(oldtype, NULL);
  53                 return (ret);
  54         }
  55
  56         do {
  57                 oldval = pthread->cancelflags;
  58                 if (oldval & THR_CANCEL_NEEDED)
  59                         break;
  60                 newval = oldval | THR_CANCEL_NEEDED;
  61         } while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
  62
  63         if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
  64                 _thr_send_sig(pthread, SIGCANCEL);
  65
  66         _thr_ref_delete(curthread, pthread);
  67         _pthread_setcanceltype(oldtype, NULL);
  68         return (0);
  69 }
  70
  71 static inline void
  72 testcancel(struct pthread *curthread)
  73 {
  74         int newval;
  75
  76         newval = curthread->cancelflags;
  77         if (SHOULD_CANCEL(newval))
  78                 _pthread_exit(PTHREAD_CANCELED);
  79 }
  80
  81 int
  82 _pthread_setcancelstate(int state, int *oldstate)
  83 {
  84         struct pthread *curthread = tls_get_curthread();
  85         int oldval, ret;
  86
  87         oldval = curthread->cancelflags;
  88         if (oldstate != NULL)
  89                 *oldstate = ((oldval & THR_CANCEL_DISABLE) ?
  90                     PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
  91         switch (state) {
  92         case PTHREAD_CANCEL_DISABLE:
  93                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
  94                 ret = 0;
  95                 break;
  96         case PTHREAD_CANCEL_ENABLE:
  97                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
  98                 testcancel(curthread);
  99                 ret = 0;
 100                 break;
 101         default:
 102                 ret = EINVAL;
 103         }
 104
 105         return (ret);
 106 }
 107
 108 int
 109 _pthread_setcanceltype(int type, int *oldtype)
 110 {
 111         struct pthread  *curthread = tls_get_curthread();
 112         int oldval, ret;
 113
 114         oldval = curthread->cancelflags;
 115         if (oldtype != NULL)
 116                 *oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
 117                                  PTHREAD_CANCEL_ASYNCHRONOUS :
 118                                  PTHREAD_CANCEL_DEFERRED);
 119         switch (type) {
 120         case PTHREAD_CANCEL_ASYNCHRONOUS:
 121                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 122                 testcancel(curthread);
 123                 ret = 0;
 124                 break;
 125         case PTHREAD_CANCEL_DEFERRED:
 126                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 127                 ret = 0;
 128                 break;
 129         default:
 130                 ret = EINVAL;
 131         }
 132
 133         return (ret);
 134 }
 135
 136 void
 137 _pthread_testcancel(void)
 138 {
 139         testcancel(tls_get_curthread());
 140 }
 141
 142 int
 143 _thr_cancel_enter(struct pthread *curthread)
 144 {
 145         int oldval;
 146
 147         oldval = curthread->cancelflags;
 148         if (!(oldval & THR_CANCEL_AT_POINT)) {
 149                 atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 150                 testcancel(curthread);
 151         }
 152         return (oldval);
 153 }
 154
 155 void
 156 _thr_cancel_leave(struct pthread *curthread, int previous)
 157 {
 158         if (!(previous & THR_CANCEL_AT_POINT))
 159                 atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 160 }
 161
 162 __strong_reference(_pthread_cancel, pthread_cancel);
 163 __strong_reference(_pthread_setcancelstate, pthread_setcancelstate);
 164 __strong_reference(_pthread_setcanceltype, pthread_setcanceltype);
 165 __strong_reference(_pthread_testcancel, pthread_testcancel);
 166