d6c88c0f27
operation, the caller is blocked util target threads are really suspended, also avoid suspending a thread when it is holding a critical lock. Fix a bug in _thr_ref_delete which tests a never set flag.
273 lines
6.6 KiB
C
273 lines
6.6 KiB
C
/*
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* Copyright (c) 2005, David Xu <davidxu@freebsd.org>
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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 unmodified, this list of conditions, and the following
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* 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/signalvar.h>
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#include <signal.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <string.h>
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#include <pthread.h>
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#include "thr_private.h"
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/* #define DEBUG_SIGNAL */
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#ifdef DEBUG_SIGNAL
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#define DBG_MSG stdout_debug
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#else
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#define DBG_MSG(x...)
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#endif
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static void
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sigcancel_handler(int sig, siginfo_t *info, ucontext_t *ucp)
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{
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struct pthread *curthread = _get_curthread();
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if (curthread->cancelflags & THR_CANCEL_AT_POINT)
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pthread_testcancel();
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_thr_ast(curthread);
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}
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void
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_thr_ast(struct pthread *curthread)
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{
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if (!THR_IN_CRITICAL(curthread)) {
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if (__predict_false((curthread->flags &
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(THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED))
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== THR_FLAGS_NEED_SUSPEND))
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_thr_suspend_check(curthread);
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}
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}
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void
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_thr_suspend_check(struct pthread *curthread)
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{
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umtx_t cycle;
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/*
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* Blocks SIGCANCEL which other threads must send.
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*/
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_thr_signal_block(curthread);
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/*
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* Increase critical_count, here we don't use THR_LOCK/UNLOCK
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* because we are leaf code, we don't want to recursively call
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* ourself.
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*/
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curthread->critical_count++;
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THR_UMTX_LOCK(curthread, &(curthread)->lock);
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while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND |
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THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) {
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curthread->cycle++;
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cycle = curthread->cycle;
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/* Wake the thread suspending us. */
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_thr_umtx_wake(&curthread->cycle, INT_MAX);
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/*
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* if we are from pthread_exit, we don't want to
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* suspend, just go and die.
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*/
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if (curthread->state == PS_DEAD)
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break;
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curthread->flags |= THR_FLAGS_SUSPENDED;
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THR_UMTX_UNLOCK(curthread, &(curthread)->lock);
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_thr_umtx_wait(&curthread->cycle, cycle, NULL);
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THR_UMTX_LOCK(curthread, &(curthread)->lock);
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curthread->flags &= ~THR_FLAGS_SUSPENDED;
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}
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THR_UMTX_UNLOCK(curthread, &(curthread)->lock);
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curthread->critical_count--;
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/*
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* Unblocks SIGCANCEL, it is possible a new SIGCANCEL is ready and
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* a new signal frame will nest us, this seems a problem because
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* stack will grow and overflow, but because kernel will automatically
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* mask the SIGCANCEL when delivering the signal, so we at most only
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* have one nesting signal frame, this should be fine.
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*/
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_thr_signal_unblock(curthread);
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}
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void
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_thr_signal_init(void)
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{
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struct sigaction act;
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/* Install cancel handler. */
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SIGEMPTYSET(act.sa_mask);
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act.sa_flags = SA_SIGINFO | SA_RESTART;
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act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler;
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__sys_sigaction(SIGCANCEL, &act, NULL);
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}
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void
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_thr_signal_deinit(void)
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{
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}
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__weak_reference(_sigaction, sigaction);
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int
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_sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
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{
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/* Check if the signal number is out of range: */
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if (sig < 1 || sig > _SIG_MAXSIG || sig == SIGCANCEL) {
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/* Return an invalid argument: */
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errno = EINVAL;
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return (-1);
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}
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return __sys_sigaction(sig, act, oact);
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}
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__weak_reference(_sigprocmask, sigprocmask);
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int
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_sigprocmask(int how, const sigset_t *set, sigset_t *oset)
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{
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const sigset_t *p = set;
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sigset_t newset;
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if (how != SIG_UNBLOCK) {
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if (set != NULL) {
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newset = *set;
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SIGDELSET(newset, SIGCANCEL);
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p = &newset;
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}
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}
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return (__sys_sigprocmask(how, p, oset));
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}
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__weak_reference(_pthread_sigmask, pthread_sigmask);
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int
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_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
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{
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if (_sigprocmask(how, set, oset))
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return (errno);
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return (0);
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}
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__weak_reference(_sigsuspend, sigsuspend);
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int
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_sigsuspend(const sigset_t * set)
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{
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struct pthread *curthread = _get_curthread();
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sigset_t newset;
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const sigset_t *pset;
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int oldcancel;
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int ret;
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if (SIGISMEMBER(*set, SIGCANCEL)) {
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newset = *set;
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SIGDELSET(newset, SIGCANCEL);
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pset = &newset;
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} else
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pset = set;
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oldcancel = _thr_cancel_enter(curthread);
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ret = __sys_sigsuspend(pset);
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_thr_cancel_leave(curthread, oldcancel);
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return (ret);
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}
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__weak_reference(__sigwait, sigwait);
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__weak_reference(__sigtimedwait, sigtimedwait);
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__weak_reference(__sigwaitinfo, sigwaitinfo);
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int
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__sigtimedwait(const sigset_t *set, siginfo_t *info,
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const struct timespec * timeout)
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{
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struct pthread *curthread = _get_curthread();
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sigset_t newset;
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const sigset_t *pset;
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int oldcancel;
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int ret;
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if (SIGISMEMBER(*set, SIGCANCEL)) {
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newset = *set;
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SIGDELSET(newset, SIGCANCEL);
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pset = &newset;
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} else
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pset = set;
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oldcancel = _thr_cancel_enter(curthread);
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ret = __sys_sigtimedwait(pset, info, timeout);
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_thr_cancel_leave(curthread, oldcancel);
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return (ret);
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}
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int
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__sigwaitinfo(const sigset_t *set, siginfo_t *info)
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{
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struct pthread *curthread = _get_curthread();
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sigset_t newset;
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const sigset_t *pset;
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int oldcancel;
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int ret;
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if (SIGISMEMBER(*set, SIGCANCEL)) {
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newset = *set;
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SIGDELSET(newset, SIGCANCEL);
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pset = &newset;
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} else
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pset = set;
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oldcancel = _thr_cancel_enter(curthread);
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ret = __sys_sigwaitinfo(pset, info);
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_thr_cancel_leave(curthread, oldcancel);
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return (ret);
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}
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int
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__sigwait(const sigset_t *set, int *sig)
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{
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struct pthread *curthread = _get_curthread();
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sigset_t newset;
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const sigset_t *pset;
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int oldcancel;
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int ret;
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if (SIGISMEMBER(*set, SIGCANCEL)) {
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newset = *set;
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SIGDELSET(newset, SIGCANCEL);
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pset = &newset;
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} else
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pset = set;
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oldcancel = _thr_cancel_enter(curthread);
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ret = __sys_sigwait(pset, sig);
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_thr_cancel_leave(curthread, oldcancel);
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return (ret);
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}
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