lib/libthr/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  * $FreeBSD$
  27  *
  28  */
  29
  30 #include "namespace.h"
  31 #include <pthread.h>
  32 #include "un-namespace.h"
  33
  34 #include "thr_private.h"
  35
  36 __weak_reference(_pthread_cancel, pthread_cancel);
  37 __weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
  38 __weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
  39 __weak_reference(_pthread_testcancel, pthread_testcancel);
  40
  41 static inline void
  42 testcancel(struct pthread *curthread)
  43 {
  44         if (__predict_false(SHOULD_CANCEL(curthread) &&
  45             !THR_IN_CRITICAL(curthread)))
  46                 _pthread_exit(PTHREAD_CANCELED);
  47 }
  48
  49 void
  50 _thr_testcancel(struct pthread *curthread)
  51 {
  52         testcancel(curthread);
  53 }
  54
  55 int
  56 _pthread_cancel(pthread_t pthread)
  57 {
  58         struct pthread *curthread = _get_curthread();
  59         int ret;
  60
  61         /*
  62          * POSIX says _pthread_cancel should be async cancellation safe.
  63          * _thr_find_thread and THR_THREAD_UNLOCK will enter and leave critical
  64          * region automatically.
  65          */
  66         if ((ret = _thr_find_thread(curthread, pthread, 0)) == 0) {
  67                 if (!pthread->cancel_pending) {
  68                         pthread->cancel_pending = 1;
  69                         if (pthread->state != PS_DEAD)
  70                                 _thr_send_sig(pthread, SIGCANCEL);
  71                 }
  72                 THR_THREAD_UNLOCK(curthread, pthread);
  73         }
  74         return (ret);
  75 }
  76
  77 int
  78 _pthread_setcancelstate(int state, int *oldstate)
  79 {
  80         struct pthread *curthread = _get_curthread();
  81         int oldval;
  82
  83         oldval = curthread->cancel_enable;
  84         switch (state) {
  85         case PTHREAD_CANCEL_DISABLE:
  86                 curthread->cancel_enable = 0;
  87                 break;
  88         case PTHREAD_CANCEL_ENABLE:
  89                 curthread->cancel_enable = 1;
  90                 if (curthread->cancel_async)
  91                         testcancel(curthread);
  92                 break;
  93         default:
  94                 return (EINVAL);
  95         }
  96
  97         if (oldstate) {
  98                 *oldstate = oldval ? PTHREAD_CANCEL_ENABLE :
  99                         PTHREAD_CANCEL_DISABLE;
 100         }
 101         return (0);
 102 }
 103
 104 int
 105 _pthread_setcanceltype(int type, int *oldtype)
 106 {
 107         struct pthread  *curthread = _get_curthread();
 108         int oldval;
 109
 110         oldval = curthread->cancel_async;
 111         switch (type) {
 112         case PTHREAD_CANCEL_ASYNCHRONOUS:
 113                 curthread->cancel_async = 1;
 114                 testcancel(curthread);
 115                 break;
 116         case PTHREAD_CANCEL_DEFERRED:
 117                 curthread->cancel_async = 0;
 118                 break;
 119         default:
 120                 return (EINVAL);
 121         }
 122
 123         if (oldtype) {
 124                 *oldtype = oldval ? PTHREAD_CANCEL_ASYNCHRONOUS :
 125                         PTHREAD_CANCEL_DEFERRED;
 126         }
 127         return (0);
 128 }
 129
 130 void
 131 _pthread_testcancel(void)
 132 {
 133         struct pthread *curthread;
 134
 135         _thr_check_init();
 136         curthread = _get_curthread();
 137         testcancel(curthread);
 138 }
 139
 140 void
 141 _thr_cancel_enter(struct pthread *curthread)
 142 {
 143         curthread->cancel_point = 1;
 144         testcancel(curthread);
 145 }
 146
 147 void
 148 _thr_cancel_enter2(struct pthread *curthread, int maycancel)
 149 {
 150         curthread->cancel_point = 1;
 151         if (__predict_false(SHOULD_CANCEL(curthread) &&
 152             !THR_IN_CRITICAL(curthread))) {
 153                 if (!maycancel)
 154                         thr_wake(curthread->tid);
 155                 else
 156                         _pthread_exit(PTHREAD_CANCELED);
 157         }
 158 }
 159
 160 void
 161 _thr_cancel_leave(struct pthread *curthread, int maycancel)
 162 {
 163         curthread->cancel_point = 0;
 164         if (__predict_false(SHOULD_CANCEL(curthread) &&
 165             !THR_IN_CRITICAL(curthread) && maycancel))
 166                 _pthread_exit(PTHREAD_CANCELED);
 167 }
 168
 169 void
 170 _pthread_cancel_enter(int maycancel)
 171 {
 172         _thr_cancel_enter2(_get_curthread(), maycancel);
 173 }
 174
 175 void
 176 _pthread_cancel_leave(int maycancel)
 177 {
 178         _thr_cancel_leave(_get_curthread(), maycancel);
 179 }