0a3fa43c7e
signal handler. Explicitly check for jumps to anywhere other than the current stack, since such jumps are undefined according to POSIX. While we're at it, convert thread cancellation to use continuations, since it's cleaner than the original cancellation code. Avoid delivering a signal to a thread twice. This was a pre-existing bug, but was likely unexposed until these other changes were made. Defer signals generated by pthread_kill() so that they can be delivered on the appropriate stack. deischen claims that this is unnecessary, which is likely true, but without this change, pthread_kill() can cause undefined priority queue states and/or PANICs in [sig|_]longjmp(), so I'm leaving this in for now. To compile this code out and exercise the bug, define the _NO_UNDISPATCH cpp macro. Defining _PTHREADS_INVARIANTS as well will cause earlier crashes. PR: kern/14685 Collaboration with: deischen
126 lines
4.0 KiB
C
126 lines
4.0 KiB
C
/*
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* Copyright (c) 1995 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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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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int
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pthread_join(pthread_t pthread, void **thread_return)
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{
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int ret = 0;
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pthread_t pthread1 = NULL;
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_thread_enter_cancellation_point();
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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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_thread_leave_cancellation_point();
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return(EINVAL);
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}
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/* Check if the caller has specified itself: */
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if (pthread == _thread_run) {
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/* Avoid a deadlock condition: */
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_thread_leave_cancellation_point();
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return(EDEADLK);
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}
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/*
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* Find the thread in the list of active threads or in the
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* list of dead threads:
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*/
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if (_find_thread(pthread) == 0 ||
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_find_dead_thread(pthread) == 0)
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pthread1 = pthread;
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if (pthread1 == NULL)
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/* Return an error: */
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ret = ESRCH;
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/* Check if this thread has been detached: */
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else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0)
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/* Return an error: */
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ret = ESRCH;
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/* Check if the thread is not dead: */
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else if (pthread->state != PS_DEAD) {
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/* Clear the interrupted flag: */
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_thread_run->interrupted = 0;
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/*
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* Protect against being context switched out while
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* adding this thread to the join queue.
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*/
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_thread_kern_sig_defer();
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/* Add the running thread to the join queue: */
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TAILQ_INSERT_TAIL(&(pthread->join_queue), _thread_run, qe);
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/* Schedule the next thread: */
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_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
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if (_thread_run->interrupted != 0)
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TAILQ_REMOVE(&(pthread->join_queue), _thread_run, qe);
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_thread_kern_sig_undefer();
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if (_thread_run->interrupted != 0 &&
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_thread_run->continuation != NULL)
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_thread_run->continuation(_thread_run);
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/* Check if the thread is not detached: */
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if ((pthread->attr.flags & PTHREAD_DETACHED) == 0) {
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/* Check if the return value is required: */
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if (thread_return)
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/* Return the thread's return value: */
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*thread_return = pthread->ret;
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}
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else
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/* Return an error: */
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ret = ESRCH;
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/* Check if the return value is required: */
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} else if (thread_return != NULL)
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/* Return the thread's return value: */
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*thread_return = pthread->ret;
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_thread_leave_cancellation_point();
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/* Return the completion status: */
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return (ret);
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}
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#endif
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