1d013a86ed
thread waiting on an event (I/O, condvar, etc) will, when resumed using pthread_resume_np, return with EINTR. For example, suspending and resuming a thread blocked on read() will not requeue the thread for the read, but will return -1 with errno = EINTR. If the suspended thread is in a critical region, the thread is suspended as soon as it leaves the critical region. Fix a bogon in pthread_kill() where a signal was being delivered twice to threads waiting in sigwait(). Reported by (suspend/resume bug): jdp Reviewed by: jasone
143 lines
4.2 KiB
C
143 lines
4.2 KiB
C
/*
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* Copyright (c) 1995-1998 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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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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static void finish_suspension(void *arg);
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/* Suspend a thread: */
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int
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pthread_suspend_np(pthread_t thread)
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{
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int ret;
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/* Find the thread in the list of active threads: */
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if ((ret = _find_thread(thread)) == 0) {
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/*
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* Defer signals to protect the scheduling queues from
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* access by the signal handler:
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*/
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_thread_kern_sig_defer();
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switch (thread->state) {
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case PS_RUNNING:
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/*
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* Remove the thread from the priority queue and
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* set the state to suspended:
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*/
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PTHREAD_PRIOQ_REMOVE(thread);
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PTHREAD_SET_STATE(thread, PS_SUSPENDED);
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break;
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case PS_SPINBLOCK:
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case PS_FDR_WAIT:
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case PS_FDW_WAIT:
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case PS_POLL_WAIT:
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case PS_SELECT_WAIT:
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/*
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* Remove these threads from the work queue
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* and mark the operation as interrupted:
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*/
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if ((thread->flags & PTHREAD_FLAGS_IN_WORKQ) != 0)
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PTHREAD_WORKQ_REMOVE(thread);
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_thread_seterrno(thread,EINTR);
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thread->interrupted = 1;
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/* FALLTHROUGH */
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case PS_SIGTHREAD:
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case PS_SLEEP_WAIT:
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case PS_WAIT_WAIT:
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case PS_SIGSUSPEND:
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case PS_SIGWAIT:
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/*
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* Remove these threads from the waiting queue and
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* set their state to suspended:
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*/
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PTHREAD_WAITQ_REMOVE(thread);
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PTHREAD_SET_STATE(thread, PS_SUSPENDED);
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break;
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case PS_MUTEX_WAIT:
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case PS_COND_WAIT:
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case PS_FDLR_WAIT:
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case PS_FDLW_WAIT:
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case PS_FILE_WAIT:
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case PS_JOIN:
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/* Mark the thread as suspended: */
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thread->suspended = 1;
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/*
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* Threads in these states may be in queues.
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* In order to preserve queue integrity, the
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* cancelled thread must remove itself from the
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* queue. Mark the thread as interrupted and
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* set the state to running. When the thread
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* resumes, it will remove itself from the queue
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* and call the suspension completion routine.
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*/
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thread->interrupted = 1;
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_thread_seterrno(thread, EINTR);
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PTHREAD_NEW_STATE(thread, PS_RUNNING);
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thread->continuation = finish_suspension;
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break;
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case PS_DEAD:
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case PS_DEADLOCK:
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case PS_STATE_MAX:
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case PS_SUSPENDED:
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/* Nothing needs to be done: */
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break;
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}
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/*
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* Undefer and handle pending signals, yielding if
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* necessary:
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*/
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_thread_kern_sig_undefer();
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}
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return(ret);
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}
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static void
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finish_suspension(void *arg)
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{
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if (_thread_run->suspended != 0)
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_thread_kern_sched_state(PS_SUSPENDED, __FILE__, __LINE__);
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}
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#endif
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