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) && curthread->cancel_defer == 0))
  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_ref_add and _thr_ref_delete will enter and leave critical
  64          * region automatically.
  65          */
  66         if ((ret = _thr_ref_add(curthread, pthread, 0)) == 0) {
  67                 THR_THREAD_LOCK(curthread, pthread);
  68                 if (!pthread->cancel_pending) {
  69                         pthread->cancel_pending = 1;
  70                         if (pthread->cancel_enable)
  71                                 _thr_send_sig(pthread, SIGCANCEL);
  72                 }
  73                 THR_THREAD_UNLOCK(curthread, pthread);
  74                 _thr_ref_delete(curthread, pthread);
  75         }
  76         return (ret);
  77 }
  78
  79 int
  80 _pthread_setcancelstate(int state, int *oldstate)
  81 {
  82         struct pthread *curthread = _get_curthread();
  83         int oldval;
  84
  85         oldval = curthread->cancel_enable;
  86         switch (state) {
  87         case PTHREAD_CANCEL_DISABLE:
  88                 THR_LOCK(curthread);
  89                 curthread->cancel_enable = 0;
  90                 THR_UNLOCK(curthread);
  91                 break;
  92         case PTHREAD_CANCEL_ENABLE:
  93                 THR_LOCK(curthread);
  94                 curthread->cancel_enable = 1;
  95                 THR_UNLOCK(curthread);
  96                 break;
  97         default:
  98                 return (EINVAL);
  99         }
 100
 101         if (oldstate) {
 102                 *oldstate = oldval ? PTHREAD_CANCEL_ENABLE :
 103                         PTHREAD_CANCEL_DISABLE;
 104         }
 105         return (0);
 106 }
 107
 108 int
 109 _pthread_setcanceltype(int type, int *oldtype)
 110 {
 111         struct pthread  *curthread = _get_curthread();
 112         int oldval;
 113
 114         oldval = curthread->cancel_async;
 115         switch (type) {
 116         case PTHREAD_CANCEL_ASYNCHRONOUS:
 117                 curthread->cancel_async = 1;
 118                 testcancel(curthread);
 119                 break;
 120         case PTHREAD_CANCEL_DEFERRED:
 121                 curthread->cancel_async = 0;
 122                 break;
 123         default:
 124                 return (EINVAL);
 125         }
 126
 127         if (oldtype) {
 128                 *oldtype = oldval ? PTHREAD_CANCEL_ASYNCHRONOUS :
 129                         PTHREAD_CANCEL_DEFERRED;
 130         }
 131         return (0);
 132 }
 133
 134 void
 135 _pthread_testcancel(void)
 136 {
 137         struct pthread *curthread = _get_curthread();
 138
 139         _thr_cancel_enter(curthread);
 140         _thr_cancel_leave(curthread);
 141 }
 142
 143 void
 144 _thr_cancel_enter(struct pthread *curthread)
 145 {
 146         if (curthread->cancel_enable) {
 147                 curthread->cancel_point++;
 148                 testcancel(curthread);
 149         }
 150 }
 151
 152 void
 153 _thr_cancel_leave(struct pthread *curthread)
 154 {
 155         if (curthread->cancel_enable)
 156                 curthread->cancel_point--;
 157 }
 158
 159 void
 160 _thr_cancel_enter_defer(struct pthread *curthread)
 161 {
 162         if (curthread->cancel_enable) {
 163                 curthread->cancel_point++;
 164                 testcancel(curthread);
 165                 curthread->cancel_defer++;
 166         }
 167 }
 168
 169 void
 170 _thr_cancel_leave_defer(struct pthread *curthread, int check)
 171 {
 172         if (curthread->cancel_enable) {
 173                 if (!check) {
 174                         curthread->cancel_point--;
 175                         curthread->cancel_defer--;
 176                 } else {
 177                         curthread->cancel_defer--;
 178                         testcancel(curthread);
 179                         curthread->cancel_point--;
 180                 }
 181         }
 182 }