/*
 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
 * 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 unmodified, 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 *
 */

#include "namespace.h"
#include <machine/tls.h>
#include <pthread.h>
#include "un-namespace.h"

#include "thr_private.h"

int
_pthread_cancel(pthread_t pthread)
{
        pthread_t curthread = tls_get_curthread();
        int oldval, newval = 0;
        int oldtype;
        int ret;

        /*
         * POSIX says _pthread_cancel should be async cancellation safe,
         * so we temporarily disable async cancellation.
         */
        _pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
        if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
                _pthread_setcanceltype(oldtype, NULL);
                return (ret);
        }

        do {
                oldval = pthread->cancelflags;
                if (oldval & THR_CANCEL_NEEDED)
                        break;
                newval = oldval | THR_CANCEL_NEEDED;
        } while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));

        if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
                _thr_send_sig(pthread, SIGCANCEL);

        _thr_ref_delete(curthread, pthread);
        _pthread_setcanceltype(oldtype, NULL);
        return (0);
}

static inline void
testcancel(pthread_t curthread)
{
        int newval;

        newval = curthread->cancelflags;
        if (SHOULD_CANCEL(newval))
                _pthread_exit(PTHREAD_CANCELED);
}

int
_pthread_setcancelstate(int state, int *oldstate)
{
        pthread_t curthread = tls_get_curthread();
        int oldval;

        oldval = curthread->cancelflags;
        if (oldstate != NULL)
                *oldstate = ((oldval & THR_CANCEL_DISABLE) ?
                    PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
        switch (state) {
        case PTHREAD_CANCEL_DISABLE:
                atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
                break;
        case PTHREAD_CANCEL_ENABLE:
                atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
                testcancel(curthread);
                break;
        default:
                return (EINVAL);
        }

        return (0);
}

int
_pthread_setcanceltype(int type, int *oldtype)
{
        pthread_t curthread = tls_get_curthread();
        int oldval;

        oldval = curthread->cancelflags;
        if (oldtype != NULL)
                *oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
                                 PTHREAD_CANCEL_ASYNCHRONOUS :
                                 PTHREAD_CANCEL_DEFERRED);
        switch (type) {
        case PTHREAD_CANCEL_ASYNCHRONOUS:
                atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
                testcancel(curthread);
                break;
        case PTHREAD_CANCEL_DEFERRED:
                atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
                break;
        default:
                return (EINVAL);
        }

        return (0);
}

void
_pthread_testcancel(void)
{
        testcancel(tls_get_curthread());
}

int
_thr_cancel_enter(pthread_t curthread)
{
        int oldval;

        oldval = curthread->cancelflags;
        if (!(oldval & THR_CANCEL_AT_POINT)) {
                atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
                testcancel(curthread);
        }
        return (oldval);
}

void
_thr_cancel_leave(pthread_t curthread, int previous)
{
        if (!(previous & THR_CANCEL_AT_POINT))
                atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
}

__strong_reference(_pthread_cancel, pthread_cancel);
__strong_reference(_pthread_setcancelstate, pthread_setcancelstate);
__strong_reference(_pthread_setcanceltype, pthread_setcanceltype);
__strong_reference(_pthread_testcancel, pthread_testcancel);