freebsd-src/lib/librt/aio.c

/*
 * 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.
 *
 * $FreeBSD$
 *
 */

#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <sys/aio.h>

#include "namespace.h"
#include <errno.h>
#include <pthread.h>
#include <stddef.h>
#include <signal.h>
#include <unistd.h>
#include "sigev_thread.h"
#include "un-namespace.h"

__weak_reference(__aio_read, _aio_read);
__weak_reference(__aio_read, aio_read);
__weak_reference(__aio_write, _aio_write);
__weak_reference(__aio_write, aio_write);
__weak_reference(__aio_return, _aio_return);
__weak_reference(__aio_return, aio_return);
__weak_reference(__aio_waitcomplete, _aio_waitcomplete);
__weak_reference(__aio_waitcomplete, aio_waitcomplete);

typedef void (*aio_func)(union sigval val, struct aiocb *iocb);

extern int __sys_aio_read(struct aiocb *iocb);
extern int __sys_aio_write(struct aiocb *iocb);
extern int __sys_aio_waitcomplete(struct aiocb **iocbp, struct timespec *timeout);
extern int __sys_aio_return(struct aiocb *iocb);
extern int __sys_aio_error(struct aiocb *iocb);

static void
aio_dispatch(struct sigev_node *sn, siginfo_t *si)
{
	aio_func f = sn->sn_func;

	f(sn->sn_value, (struct aiocb *)sn->sn_id);
}

static int
aio_io(struct aiocb *iocb, int (*sysfunc)(struct aiocb *iocb))
{
	struct sigev_node *sn;
	struct sigevent saved_ev;
	int ret;

	if (iocb->aio_sigevent.sigev_notify != SIGEV_THREAD) {
		ret = sysfunc(iocb);
		return (ret);
	}

	if (__sigev_check_init()) {
		/* This might be that thread library is not enabled. */
		errno = EINVAL;
		return (-1);
	}

	sn = __sigev_alloc(SI_ASYNCIO, &iocb->aio_sigevent);
	if (sn == NULL) {
		errno = EAGAIN;
		return (-1);
	}
	
	saved_ev = iocb->aio_sigevent;
	sn->sn_id = (sigev_id_t)iocb;
	sn->sn_flags |= SNF_ONESHOT;
	__sigev_get_sigevent(sn, &iocb->aio_sigevent, sn->sn_id);

	__sigev_list_lock();
	__sigev_register(sn);
	__sigev_list_unlock();

	sn->sn_dispatch = aio_dispatch;
	ret = sysfunc(iocb);
	iocb->aio_sigevent = saved_ev;

	if (ret != 0) {
		__sigev_list_lock();
		__sigev_delete_node(sn);
		__sigev_list_unlock();
	}
	return (ret);
}

int
__aio_read(struct aiocb *iocb)
{
	return aio_io(iocb, &__sys_aio_read);
}

int
__aio_write(struct aiocb *iocb)
{
	return aio_io(iocb, &__sys_aio_write);
}

int
__aio_waitcomplete(struct aiocb **iocbp, struct timespec *timeout)
{
	int ret = __sys_aio_waitcomplete(iocbp, timeout);

	if (*iocbp) {
		if ((*iocbp)->aio_sigevent.sigev_notify == SIGEV_THREAD) {
			__sigev_list_lock();
			__sigev_delete(SI_ASYNCIO, (sigev_id_t)(*iocbp));
			__sigev_list_unlock();
		}
	}

	return (ret);
}

int
__aio_return(struct aiocb *iocb)
{
	int ret = __sys_aio_return(iocb);
	int err = __sys_aio_error(iocb);

	if (err != EINPROGRESS &&
	    iocb->aio_sigevent.sigev_notify == SIGEV_THREAD) {
		__sigev_list_lock();
		__sigev_delete(SI_ASYNCIO, (sigev_id_t)iocb);
		__sigev_list_unlock();
	}

	return (ret);
}