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