0f020d18b1
Removed 'join_count' from pthread_internal_t and switched to using the flag PTHREAD_ATTR_FLAG_JOINED to indicate if a thread is being joined. Combined with a switch to a while loop in pthread_join, this fixes spurious wake-ups but prevents a thread from being joined multiple times. This is fine for two reasons: 1) The pthread_join specification allows for undefined behavior when multiple threads try to join a single thread. 2) There is no thread safe way to allow multiple threads to join a single thread with the pthread interface. The second thread calling pthread_join could be pre-empted until the thread is destroyed and its handle reused for a different thread. Therefore multi-join is always an error. Bug: https://code.google.com/p/android/issues/detail?id=52255 Change-Id: I8b6784d47620ffdcdbfb14524e7402e21d46c5f7
63 lines
2.1 KiB
C++
63 lines
2.1 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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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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* * 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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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* 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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#include <errno.h>
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#include "pthread_accessor.h"
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int pthread_join(pthread_t t, void** ret_val) {
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if (t == pthread_self()) {
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return EDEADLK;
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}
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pthread_accessor thread(t);
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if (thread.get() == NULL) {
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return ESRCH;
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}
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if (thread->attr.flags & PTHREAD_ATTR_FLAG_DETACHED) {
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return EINVAL;
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}
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if (thread->attr.flags & PTHREAD_ATTR_FLAG_JOINED) {
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return EINVAL;
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}
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// Signal our intention to join, and wait for the thread to exit.
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thread->attr.flags |= PTHREAD_ATTR_FLAG_JOINED;
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while ((thread->attr.flags & PTHREAD_ATTR_FLAG_ZOMBIE) == 0) {
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pthread_cond_wait(&thread->join_cond, &gThreadListLock);
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}
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if (ret_val) {
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*ret_val = thread->return_value;
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}
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_pthread_internal_remove_locked(thread.get());
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return 0;
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}
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