/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * routines to wait and wake up a client waiting on a list for a
 * name service request
 */
#include "cache.h"

int
nscd_wait(nsc_ctx_t *ctx, nsc_db_t *nscdb, nsc_entry_t *entry)
{
	waiter_t	mywait;
	waiter_t	*wchan = &nscdb->db_wait;

	(void) cond_init(&(mywait.w_waitcv), USYNC_THREAD, 0);
	mywait.w_key = entry;
	mywait.w_signaled = 0;
	mywait.w_next = wchan->w_next;
	mywait.w_prev = wchan;
	if (mywait.w_next)
		mywait.w_next->w_prev = &mywait;
	wchan->w_next = &mywait;

	(void) mutex_lock(&ctx->stats_mutex);
	ctx->stats.wait_count++;
	(void) mutex_unlock(&ctx->stats_mutex);

	while (!mywait.w_signaled)
		(void) cond_wait(&(mywait.w_waitcv), &nscdb->db_mutex);
	if (mywait.w_prev)
		mywait.w_prev->w_next = mywait.w_next;
	if (mywait.w_next)
		mywait.w_next->w_prev = mywait.w_prev;
	return (0);
}

int
nscd_signal(nsc_ctx_t *ctx, nsc_db_t *nscdb, nsc_entry_t *entry)
{
	int		c = 0;
	waiter_t	*wchan = &nscdb->db_wait;
	waiter_t	*tmp = wchan->w_next;

	while (tmp) {
		if (tmp->w_key == entry) {
			(void) cond_signal(&(tmp->w_waitcv));
			tmp->w_signaled = 1;

			(void) mutex_lock(&ctx->stats_mutex);
			ctx->stats.wait_count--;
			(void) mutex_unlock(&ctx->stats_mutex);
			c++;
		}
		tmp = tmp->w_next;
	}

	return (c);
}