/*-
 * Copyright (c) 2005 Hans Petter Selasky. 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 */

#include <bsd_module_all.h>

static struct eventhandler_list evh_list[16];

static void
eventhandler_init(void *arg)
{
	uint8_t x;

	for (x = 0; x != (sizeof(evh_list) / sizeof(evh_list[0])); x++) {
		mtx_init(&evh_list[x].el_mtx, "eventhandler", NULL, MTX_DEF);
	}
	return;
}

SYSINIT(eventhandler_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, eventhandler_init, NULL);

struct eventhandler_list *
eventhandler_get_list(const char *name)
{
	/* XXX this should be dynamic */

	if (strcmp(name, "dev_clone") == 0)
		return &evh_list[0];
	if (strcmp(name, "shutdown_pre_sync") == 0)
		return &evh_list[1];
	if (strcmp(name, "shutdown_post_sync") == 0)
		return &evh_list[2];
	if (strcmp(name, "shutdown_final") == 0)
		return &evh_list[3];
	if (strcmp(name, "vm_lowmem") == 0)
		return &evh_list[4];
	if (strcmp(name, "process_exit") == 0)
		return &evh_list[5];
	if (strcmp(name, "process_fork") == 0)
		return &evh_list[6];
	if (strcmp(name, "process_exec") == 0)
		return &evh_list[7];
	else
		printf("unknown eventhandler list: %s! (FIXME)\n", name);

	return NULL;
}

eventhandler_tag
eventhandler_register(struct eventhandler_list *list,
    const char *name, void *func, void *arg,
    int priority)
{
	struct eventhandler_entry *ptr;

	list = eventhandler_get_list(name);

	if (list == NULL) {
		return NULL;
	}
	mtx_lock(&list->el_mtx);
	ptr = list->el_root;
	while (ptr) {
		if (ptr->used == 0) {
			ptr->used = 1;
			break;
		}
		ptr = ptr->next;
	}
	mtx_unlock(&list->el_mtx);

	if (ptr == NULL) {
		ptr = malloc(sizeof(*ptr), M_TEMP, M_ZERO | M_WAITOK);
	}
	if (ptr == NULL) {
		return NULL;
	}
	ptr->func = func;
	ptr->arg = arg;

	if (ptr->used == 0) {
		ptr->used = 1;

		mtx_lock(&list->el_mtx);
		ptr->next = list->el_root;
		list->el_root = ptr;
		mtx_unlock(&list->el_mtx);
	}
	return ptr;
}

void
eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
{
	struct eventhandler_entry *ptr;

	if (list == NULL) {
		return;
	}
	mtx_lock(&list->el_mtx);
	ptr = list->el_root;
	while (ptr) {
		if (ptr == tag) {
			ptr->used = 0;
			break;
		}
		ptr = ptr->next;
	}
	mtx_unlock(&list->el_mtx);
	return;
}