lib/libthread_xu/thread/thr_join.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, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "namespace.h"
  27 #include <machine/tls.h>
  28 #include <errno.h>
  29 #include <pthread.h>
  30 #include "un-namespace.h"
  31
  32 #include "thr_private.h"
  33
  34 #define cpu_ccfence()       __asm __volatile("" : : : "memory")
  35
  36 int _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
  37         const struct timespec *abstime);
  38
  39 static int join_common(pthread_t, void **, const struct timespec *);
  40
  41 static void backout_join(void *arg)
  42 {
  43         struct pthread *curthread = tls_get_curthread();
  44         struct pthread *pthread = (struct pthread *)arg;
  45
  46         THREAD_LIST_LOCK(curthread);
  47         pthread->joiner = NULL;
  48         THREAD_LIST_UNLOCK(curthread);
  49 }
  50
  51 int
  52 _pthread_join(pthread_t pthread, void **thread_return)
  53 {
  54         return (join_common(pthread, thread_return, NULL));
  55 }
  56
  57 int
  58 _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
  59         const struct timespec *abstime)
  60 {
  61         if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
  62             abstime->tv_nsec >= 1000000000)
  63                 return (EINVAL);
  64
  65         return (join_common(pthread, thread_return, abstime));
  66 }
  67
  68 static int
  69 join_common(pthread_t pthread, void **thread_return,
  70         const struct timespec *abstime)
  71 {
  72         struct pthread *curthread = tls_get_curthread();
  73         struct timespec ts, ts2, *tsp;
  74         void *tmp;
  75         long state;
  76         int oldcancel;
  77         int ret = 0;
  78
  79         if (pthread == NULL)
  80                 return (EINVAL);
  81
  82         if (pthread == curthread)
  83                 return (EDEADLK);
  84
  85         THREAD_LIST_LOCK(curthread);
  86         if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0) {
  87                 ret = ESRCH;
  88         } else if ((pthread->tlflags & TLFLAGS_DETACHED) != 0) {
  89                 ret = EINVAL;
  90         } else if (pthread->joiner != NULL) {
  91                 /* Multiple joiners are not supported. */
  92                 ret = ENOTSUP;
  93         }
  94         if (ret) {
  95                 THREAD_LIST_UNLOCK(curthread);
  96                 return (ret);
  97         }
  98         /* Set the running thread to be the joiner: */
  99         pthread->joiner = curthread;
 100
 101         THREAD_LIST_UNLOCK(curthread);
 102
 103         THR_CLEANUP_PUSH(curthread, backout_join, pthread);
 104         oldcancel = _thr_cancel_enter(curthread);
 105
 106         while ((state = pthread->state) != PS_DEAD) {
 107                 cpu_ccfence();
 108                 if (abstime != NULL) {
 109                         clock_gettime(CLOCK_REALTIME, &ts);
 110                         TIMESPEC_SUB(&ts2, abstime, &ts);
 111                         if (ts2.tv_sec < 0) {
 112                                 ret = ETIMEDOUT;
 113                                 break;
 114                         }
 115                         tsp = &ts2;
 116                 } else
 117                         tsp = NULL;
 118                 ret = _thr_umtx_wait(&pthread->state, state, tsp,
 119                          CLOCK_REALTIME);
 120                 if (ret == ETIMEDOUT)
 121                         break;
 122         }
 123
 124         _thr_cancel_leave(curthread, oldcancel);
 125         THR_CLEANUP_POP(curthread, 0);
 126
 127         if (ret == ETIMEDOUT) {
 128                 THREAD_LIST_LOCK(curthread);
 129                 pthread->joiner = NULL;
 130                 THREAD_LIST_UNLOCK(curthread);
 131         } else {
 132                 ret = 0;
 133                 tmp = pthread->ret;
 134                 THREAD_LIST_LOCK(curthread);
 135                 pthread->tlflags |= TLFLAGS_DETACHED;
 136                 pthread->joiner = NULL;
 137                 THR_GCLIST_ADD(pthread);
 138                 THREAD_LIST_UNLOCK(curthread);
 139
 140                 if (thread_return != NULL)
 141                         *thread_return = tmp;
 142         }
 143         return (ret);
 144 }
 145
 146 __strong_reference(_pthread_join, pthread_join);
 147 __strong_reference(_pthread_timedjoin_np, pthread_timedjoin_np);