lib/libthr/thread/thr_join.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice unmodified, this list of conditions, and the following
  12  *    disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include "namespace.h"
  33 #include <errno.h>
  34 #include <pthread.h>
  35 #include "un-namespace.h"
  36
  37 #include "thr_private.h"
  38
  39 int     _pthread_peekjoin_np(pthread_t pthread, void **thread_return);
  40 int     _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
  41             const struct timespec *abstime);
  42 static int join_common(pthread_t, void **, const struct timespec *, bool peek);
  43
  44 __weak_reference(_thr_join, pthread_join);
  45 __weak_reference(_thr_join, _pthread_join);
  46 __weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
  47 __weak_reference(_pthread_peekjoin_np, pthread_peekjoin_np);
  48
  49 static void backout_join(void *arg)
  50 {
  51         struct pthread *pthread = (struct pthread *)arg;
  52         struct pthread *curthread = _get_curthread();
  53
  54         THR_THREAD_LOCK(curthread, pthread);
  55         pthread->joiner = NULL;
  56         THR_THREAD_UNLOCK(curthread, pthread);
  57 }
  58
  59 int
  60 _thr_join(pthread_t pthread, void **thread_return)
  61 {
  62         return (join_common(pthread, thread_return, NULL, false));
  63 }
  64
  65 int
  66 _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
  67         const struct timespec *abstime)
  68 {
  69         if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
  70             abstime->tv_nsec >= 1000000000)
  71                 return (EINVAL);
  72
  73         return (join_common(pthread, thread_return, abstime, false));
  74 }
  75
  76 int
  77 _pthread_peekjoin_np(pthread_t pthread, void **thread_return)
  78 {
  79         return (join_common(pthread, thread_return, NULL, true));
  80 }
  81
  82 /*
  83  * Cancellation behavior:
  84  *   if the thread is canceled, joinee is not recycled.
  85  */
  86 static int
  87 join_common(pthread_t pthread, void **thread_return,
  88     const struct timespec *abstime, bool peek)
  89 {
  90         struct pthread *curthread = _get_curthread();
  91         struct timespec ts, ts2, *tsp;
  92         void *tmp;
  93         long tid;
  94         int ret;
  95
  96         if (pthread == NULL)
  97                 return (EINVAL);
  98
  99         if (pthread == curthread)
 100                 return (EDEADLK);
 101
 102         if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0)
 103                 return (ESRCH);
 104
 105         if ((pthread->flags & THR_FLAGS_DETACHED) != 0) {
 106                 ret = EINVAL;
 107         } else if (pthread->joiner != NULL) {
 108                 /* Multiple joiners are not supported. */
 109                 ret = ENOTSUP;
 110         }
 111         if (ret != 0) {
 112                 THR_THREAD_UNLOCK(curthread, pthread);
 113                 return (ret);
 114         }
 115
 116         /* Only peek into status, do not gc the thread. */
 117         if (peek) {
 118                 if (pthread->tid != TID_TERMINATED)
 119                         ret = EBUSY;
 120                 else if (thread_return != NULL)
 121                         *thread_return = pthread->ret;
 122                 THR_THREAD_UNLOCK(curthread, pthread);
 123                 return (ret);
 124         }
 125
 126         /* Set the running thread to be the joiner: */
 127         pthread->joiner = curthread;
 128
 129         THR_THREAD_UNLOCK(curthread, pthread);
 130
 131         THR_CLEANUP_PUSH(curthread, backout_join, pthread);
 132         _thr_cancel_enter(curthread);
 133
 134         tid = pthread->tid;
 135         while (pthread->tid != TID_TERMINATED) {
 136                 _thr_testcancel(curthread);
 137                 if (abstime != NULL) {
 138                         clock_gettime(CLOCK_REALTIME, &ts);
 139                         TIMESPEC_SUB(&ts2, abstime, &ts);
 140                         if (ts2.tv_sec < 0) {
 141                                 ret = ETIMEDOUT;
 142                                 break;
 143                         }
 144                         tsp = &ts2;
 145                 } else
 146                         tsp = NULL;
 147                 ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
 148                 if (ret == ETIMEDOUT)
 149                         break;
 150         }
 151
 152         _thr_cancel_leave(curthread, 0);
 153         THR_CLEANUP_POP(curthread, 0);
 154
 155         if (ret == ETIMEDOUT) {
 156                 THR_THREAD_LOCK(curthread, pthread);
 157                 pthread->joiner = NULL;
 158                 THR_THREAD_UNLOCK(curthread, pthread);
 159         } else {
 160                 ret = 0;
 161                 tmp = pthread->ret;
 162                 THR_THREAD_LOCK(curthread, pthread);
 163                 pthread->flags |= THR_FLAGS_DETACHED;
 164                 pthread->joiner = NULL;
 165                 _thr_try_gc(curthread, pthread); /* thread lock released */
 166
 167                 if (thread_return != NULL)
 168                         *thread_return = tmp;
 169         }
 170         return (ret);
 171 }