d80384bc8d
its waitset, but if the signal is not masked by the thread, the signal can interrupt the thread and signal action can be invoked by the thread, sigwait should return with errno set to EINTR. Also save and restore thread internal state(timeout and interrupted) around signal handler invoking.
255 lines
7.0 KiB
C
255 lines
7.0 KiB
C
//depot/projects/kse/lib/libpthread/thread/thr_sigwait.c#1 - branch change 15154 (text+ko)
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/*
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* Copyright (c) 1997 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 <signal.h>
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#include <sys/param.h>
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#include <sys/signalvar.h>
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#include <errno.h>
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#include <pthread.h>
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#include "thr_private.h"
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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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static int
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lib_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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int ret = 0;
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int i;
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sigset_t tempset, waitset;
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struct sigaction act;
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kse_critical_t crit;
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siginfo_t siginfo;
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if (!_kse_isthreaded()) {
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if (info == NULL)
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info = &siginfo;
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return __sys_sigtimedwait((sigset_t *)set, info,
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(struct timespec *)timeout);
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}
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/*
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* Specify the thread kernel signal handler.
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*/
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act.sa_handler = (void (*) ()) _thr_sig_handler;
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act.sa_flags = SA_RESTART | SA_SIGINFO;
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/* Ensure the signal handler cannot be interrupted by other signals: */
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SIGFILLSET(act.sa_mask);
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/*
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* Initialize the set of signals that will be waited on:
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*/
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waitset = *set;
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/* These signals can't be waited on. */
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SIGDELSET(waitset, SIGKILL);
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SIGDELSET(waitset, SIGSTOP);
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crit = _kse_critical_enter();
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KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
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/*
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* Enter a loop to find the signals that are SIG_DFL. For
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* these signals we must install a dummy signal handler in
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* order for the kernel to pass them in to us. POSIX says
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* that the _application_ must explicitly install a dummy
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* handler for signals that are SIG_IGN in order to sigwait
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* on them. Note that SIG_IGN signals are left in the
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* mask because a subsequent sigaction could enable an
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* ignored signal.
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*/
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SIGEMPTYSET(tempset);
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for (i = 1; i <= _SIG_MAXSIG; i++) {
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if (SIGISMEMBER(waitset, i) &&
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(_thread_sigact[i - 1].sa_handler == SIG_DFL)) {
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_thread_dfl_count[i - 1]++;
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SIGADDSET(tempset, i);
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if (_thread_dfl_count[i - 1] == 1) {
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if (__sys_sigaction(i, &act, NULL) != 0)
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/* ret = -1 */;
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}
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}
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}
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if (ret == 0) {
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/* Done accessing _thread_dfl_count for now. */
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KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
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KSE_SCHED_LOCK(curthread->kse, curthread->kseg);
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for (i = 1; i <= _SIG_MAXSIG; ++i) {
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if (SIGISMEMBER(waitset, i) &&
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SIGISMEMBER(curthread->sigpend, i)) {
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SIGDELSET(curthread->sigpend, i);
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siginfo = curthread->siginfo[i - 1];
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KSE_SCHED_UNLOCK(curthread->kse,
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curthread->kseg);
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KSE_LOCK_ACQUIRE(curthread->kse,
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&_thread_signal_lock);
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ret = i;
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goto OUT;
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}
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}
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curthread->timeout = 0;
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curthread->interrupted = 0;
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_thr_set_timeout(timeout);
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/* Wait for a signal: */
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curthread->oldsigmask = curthread->sigmask;
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siginfo.si_signo = 0;
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curthread->data.sigwaitinfo = &siginfo;
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SIGFILLSET(curthread->sigmask);
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SIGSETNAND(curthread->sigmask, waitset);
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THR_SET_STATE(curthread, PS_SIGWAIT);
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_thr_sched_switch_unlocked(curthread);
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/*
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* Return the signal number to the caller:
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*/
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if (siginfo.si_signo > 0) {
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ret = siginfo.si_signo;
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} else {
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if (curthread->interrupted)
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errno = EINTR;
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else if (curthread->timeout)
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errno = EAGAIN;
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ret = -1;
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}
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curthread->timeout = 0;
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curthread->interrupted = 0;
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/*
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* Probably unnecessary, but since it's in a union struct
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* we don't know how it could be used in the future.
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*/
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crit = _kse_critical_enter();
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curthread->data.sigwaitinfo = NULL;
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/*
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* Relock the array of SIG_DFL wait counts.
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*/
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KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
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}
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OUT:
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/* Restore the sigactions: */
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act.sa_handler = SIG_DFL;
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for (i = 1; i <= _SIG_MAXSIG; i++) {
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if (SIGISMEMBER(tempset, i)) {
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_thread_dfl_count[i - 1]--;
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if ((_thread_sigact[i - 1].sa_handler == SIG_DFL) &&
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(_thread_dfl_count[i - 1] == 0)) {
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if (__sys_sigaction(i, &act, NULL) != 0)
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/* ret = -1 */ ;
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}
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}
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}
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/* Done accessing _thread_dfl_count. */
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KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
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_kse_critical_leave(crit);
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if (ret > 0 && info != NULL)
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*info = siginfo;
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return (ret);
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}
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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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int ret;
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_thr_enter_cancellation_point(curthread);
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ret = lib_sigtimedwait(set, info, timeout);
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_thr_leave_cancellation_point(curthread);
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return (ret);
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}
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int _sigtimedwait(const sigset_t *set, siginfo_t *info,
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const struct timespec * timeout)
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{
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return lib_sigtimedwait(set, info, timeout);
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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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int ret;
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_thr_enter_cancellation_point(curthread);
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ret = lib_sigtimedwait(set, info, NULL);
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_thr_leave_cancellation_point(curthread);
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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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return lib_sigtimedwait(set, info, NULL);
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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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int ret;
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_thr_enter_cancellation_point(curthread);
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ret = lib_sigtimedwait(set, NULL, NULL);
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if (ret > 0) {
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*sig = ret;
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ret = 0;
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}
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else
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ret = -1;
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_thr_leave_cancellation_point(curthread);
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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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int ret;
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ret = lib_sigtimedwait(set, NULL, NULL);
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if (ret > 0) {
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*sig = ret;
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ret = 0;
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} else {
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ret = -1;
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}
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return (ret);
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}
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