freebsd-dev/lib/libpthread/thread/thr_sigsuspend.c

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/*
* Copyright (c) 1995 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.
*
1999-08-28 00:22:10 +00:00
* $FreeBSD$
*/
#include <signal.h>
#include <errno.h>
#include <pthread.h>
#include <string.h>
#include <sys/signalvar.h>
#include "thr_private.h"
__weak_reference(__sigsuspend, sigsuspend);
int
_sigsuspend(const sigset_t *set)
{
struct pthread *curthread = _get_curthread();
sigset_t oldmask, newmask, tempset;
int ret = -1;
o Use a daemon thread to monitor signal events in kernel, if pending signals were changed in kernel, it will retrieve the pending set and try to find a thread to dispatch the signal. The dispatching process can be rolled back if the signal is no longer in kernel. o Create two functions _thr_signal_init() and _thr_signal_deinit(), all signal action settings are retrieved from kernel when threading mode is turned on, after a fork(), child process will reset them to user settings by calling _thr_signal_deinit(). when threading mode is not turned on, all signal operations are direct past to kernel. o When a thread generated a synchoronous signals and its context returned from completed list, UTS will retrieve the signal from its mailbox and try to deliver the signal to thread. o Context signal mask is now only used when delivering signals, thread's current signal mask is always the one in pthread structure. o Remove have_signals field in pthread structure, replace it with psf_valid in pthread_signal_frame. when psf_valid is true, in context switch time, thread will backout itself from some mutex/condition internal queues, then begin to process signals. when a thread is not at blocked state and running, check_pending indicates there are signals for the thread, after preempted and then resumed time, UTS will try to deliver signals to the thread. o At signal delivering time, not only pending signals in thread will be scanned, process's pending signals will be scanned too. o Change sigwait code a bit, remove field sigwait in pthread_wait_data, replace it with oldsigmask in pthread structure, when a thread calls sigwait(), its current signal mask is backuped to oldsigmask, and waitset is copied to its signal mask and when the thread gets a signal in the waitset range, its current signal mask is restored from oldsigmask, these are done in atomic fashion. o Two additional POSIX APIs are implemented, sigwaitinfo() and sigtimedwait(). o Signal code locking is better than previous, there is fewer race conditions. o Temporary disable most of code in _kse_single_thread as it is not safe after fork().
2003-06-28 09:55:02 +00:00
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
return (__sys_sigsuspend(set));
/* Check if a new signal set was provided by the caller: */
if (set != NULL) {
newmask = *set;
SIG_CANTMASK(newmask);
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THR_LOCK_SWITCH(curthread);
/* Save current sigmask: */
oldmask = curthread->sigmask;
curthread->oldsigmask = &oldmask;
/* Change the caller's mask: */
curthread->sigmask = newmask;
tempset = curthread->sigpend;
SIGSETNAND(tempset, newmask);
if (SIGISEMPTY(tempset)) {
THR_SET_STATE(curthread, PS_SIGSUSPEND);
/* Wait for a signal: */
_thr_sched_switch_unlocked(curthread);
} else {
curthread->check_pending = 1;
THR_UNLOCK_SWITCH(curthread);
/* check pending signal I can handle: */
_thr_sig_check_pending(curthread);
}
if ((curthread->cancelflags & THR_CANCELLING) != 0)
curthread->oldsigmask = NULL;
else {
THR_ASSERT(curthread->oldsigmask == NULL,
"oldsigmask is not cleared");
}
/* Always return an interrupted error: */
errno = EINTR;
} else {
/* Return an invalid argument error: */
errno = EINVAL;
}
/* Return the completion status: */
return (ret);
}
int
__sigsuspend(const sigset_t * set)
{
struct pthread *curthread = _get_curthread();
int ret;
_thr_cancel_enter(curthread);
ret = _sigsuspend(set);
_thr_cancel_leave(curthread, 1);
return (ret);
}