411db152c0
atomically: 1) Search _thread_list for the thread to join. 2) Search _dead_list for the thread to join. 3) Set the running thread as the joiner. While we're at it, fix a race in the case where multiple threads try to join on the same thread. POSIX says that the behavior of multiple joiners is undefined, but the fix is cheap as a result of the other fix.
67 lines
2.5 KiB
C
67 lines
2.5 KiB
C
/*
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* Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <pthread.h>
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#include "pthread_private.h"
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/* Find a thread in the linked list of active threads: */
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int
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_find_thread(pthread_t pthread)
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{
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pthread_t pthread1;
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/* Check if the caller has specified an invalid thread: */
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if (pthread == NULL || pthread->magic != PTHREAD_MAGIC)
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/* Invalid thread: */
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return(EINVAL);
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/*
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* Defer signals to protect the thread list from access
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* by the signal handler:
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*/
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_thread_kern_sig_defer();
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/* Search for the specified thread: */
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TAILQ_FOREACH(pthread1, &_thread_list, tle) {
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if (pthread == pthread1)
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break;
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}
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/* Undefer and handle pending signals, yielding if necessary: */
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_thread_kern_sig_undefer();
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/* Return zero if the thread exists: */
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return ((pthread1 != NULL) ? 0:ESRCH);
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}
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