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/* $OpenBSD: uthread_sigwait.c,v 1.11 2002/10/30 19:11:56 marc Exp $ */
/*
* Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: uthread_sigwait.c,v 1.10 1999/09/30 14:51:31 marcel Exp $
*/
#include <signal.h>
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
sigwait(const sigset_t * set, int *sig)
{
struct pthread *curthread = _get_curthread();
int ret = 0;
int i;
sigset_t tempset, waitset;
struct sigaction act;
_thread_enter_cancellation_point();
/*
* Specify the thread kernel signal handler.
*/
act.sa_handler = (void (*) ()) _thread_sig_handler;
act.sa_flags = SA_SIGINFO | SA_RESTART;
/* Ensure the signal handler cannot be interrupted by other signals: */
sigfillset(&act.sa_mask);
/*
* Initialize the set of signals that will be waited on:
*/
waitset = *set;
/* These signals can't be waited on. */
sigdelset(&waitset, SIGKILL);
sigdelset(&waitset, SIGSTOP);
sigdelset(&waitset, _SCHED_SIGNAL);
sigdelset(&waitset, SIGCHLD);
sigdelset(&waitset, SIGINFO);
/* Check to see if a pending signal is in the wait mask. */
tempset = curthread->sigpend;
tempset |= _process_sigpending;
tempset &= waitset;
if (tempset != 0) {
/* Enter a loop to find a pending signal: */
for (i = 1; i < NSIG; i++) {
if (sigismember(&tempset, i))
break;
}
/* Clear the pending signal: */
if (sigismember(&curthread->sigpend, i))
sigdelset(&curthread->sigpend, i);
else
sigdelset(&_process_sigpending, i);
/* Return the signal number to the caller: */
*sig = i;
_thread_leave_cancellation_point();
return (0);
}
/*
* Access the _thread_dfl_count array under the protection of signal
* deferral.
*/
_thread_kern_sig_defer();
/*
* Enter a loop to find the signals that are SIG_DFL. For
* these signals we must install a dummy signal handler in
* order for the kernel to pass them in to us. POSIX says
* that the _application_ must explicitly install a dummy
* handler for signals that are SIG_IGN in order to sigwait
* on them. Note that SIG_IGN signals are left in the
* mask because a subsequent sigaction could enable an
* ignored signal.
*/
sigemptyset(&tempset);
for (i = 1; i < NSIG; i++) {
if (sigismember(&waitset, i) &&
(_thread_sigact[i - 1].sa_handler == SIG_DFL)) {
_thread_dfl_count[i]++;
sigaddset(&tempset, i);
if (_thread_dfl_count[i] == 1) {
if (_thread_sys_sigaction(i, &act, NULL) != 0)
ret = -1;
}
}
}
/* Done accessing _thread_dfl_count for now. */
_thread_kern_sig_undefer();
if (ret == 0) {
/*
* Save the wait signal mask. The wait signal
* mask is independent of the threads signal mask
* and requires separate storage.
*/
curthread->data.sigwait = &waitset;
/* Wait for a signal: */
_thread_kern_sched_state(PS_SIGWAIT, __FILE__, __LINE__);
/* Return the signal number to the caller: */
*sig = curthread->signo;
/*
* Probably unnecessary, but since it's in a union struct
* we don't know how it could be used in the future.
*/
curthread->data.sigwait = NULL;
}
/*
* Access the _thread_dfl_count array under the protection of signal
* deferral.
*/
_thread_kern_sig_defer();
/* Restore the sigactions: */
act.sa_handler = SIG_DFL;
for (i = 1; i < NSIG; i++) {
if (sigismember(&tempset, i)) {
_thread_dfl_count[i]--;
if ((_thread_sigact[i - 1].sa_handler == SIG_DFL) &&
(_thread_dfl_count[i] == 0)) {
if (_thread_sys_sigaction(i, &act, NULL) != 0)
ret = -1;
}
}
}
/* Done accessing _thread_dfl_count. */
_thread_kern_sig_undefer();
_thread_leave_cancellation_point();
/* Return the completion status: */
return (ret);
}
#endif
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