/*
 * util/winsock_event.c - implementation of the unbound winsock event handler. 
 *
 * Copyright (c) 2008, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * 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.
 * 
 * Neither the name of the NLNET LABS 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 COPYRIGHT HOLDERS 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 COPYRIGHT
 * HOLDER 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.
 */
/**
 * \file
 * Implementation of the unbound WinSock2 API event notification handler
 * for the Windows port.
 */

#include "config.h"
#ifdef USE_WINSOCK
#include <signal.h>
#ifdef HAVE_TIME_H
#include <time.h>
#endif
#include <sys/time.h>
#include "util/winsock_event.h"
#include "util/fptr_wlist.h"

int mini_ev_cmp(const void* a, const void* b)
{
        const struct event *e = (const struct event*)a;
        const struct event *f = (const struct event*)b;
        if(e->ev_timeout.tv_sec < f->ev_timeout.tv_sec)
                return -1;
        if(e->ev_timeout.tv_sec > f->ev_timeout.tv_sec)
                return 1;
        if(e->ev_timeout.tv_usec < f->ev_timeout.tv_usec)
                return -1;
        if(e->ev_timeout.tv_usec > f->ev_timeout.tv_usec)
                return 1;
        if(e < f)
                return -1;
        if(e > f)
                return 1;
        return 0;
}

/** set time */
static int
settime(struct event_base* base)
{
        if(gettimeofday(base->time_tv, NULL) < 0) {
                return -1;
        }
#ifndef S_SPLINT_S
        *base->time_secs = (time_t)base->time_tv->tv_sec;
#endif
        return 0;
}

#ifdef UNBOUND_DEBUG
/**
 * Find a fd in the list of items.
 * Note that not all items have a fd associated (those are -1).
 * Signals are stored separately, and not searched.
 * @param base: event base to look in.
 * @param fd: what socket to look for.
 * @return the index in the array, or -1 on failure.
 */
static int
find_fd(struct event_base* base, int fd)
{
        int i;
        for(i=0; i<base->max; i++) {
                if(base->items[i]->ev_fd == fd)
                        return i;
        }
        return -1;
}
#endif

/** Find ptr in base array */
static void
zero_waitfor(WSAEVENT waitfor[], WSAEVENT x)
{
        int i;
        for(i=0; i<WSK_MAX_ITEMS; i++) {
                if(waitfor[i] == x)
                        waitfor[i] = 0;
        }
}

void *event_init(time_t* time_secs, struct timeval* time_tv)
{
        struct event_base* base = (struct event_base*)malloc(
                sizeof(struct event_base));
        if(!base)
                return NULL;
        memset(base, 0, sizeof(*base));
        base->time_secs = time_secs;
        base->time_tv = time_tv;
        if(settime(base) < 0) {
                event_base_free(base);
                return NULL;
        }
        base->items = (struct event**)calloc(WSK_MAX_ITEMS, 
                sizeof(struct event*));
        if(!base->items) {
                event_base_free(base);
                return NULL;
        }
        base->cap = WSK_MAX_ITEMS;
        base->max = 0;
        base->times = rbtree_create(mini_ev_cmp);
        if(!base->times) {
                event_base_free(base);
                return NULL;
        }
        base->signals = (struct event**)calloc(MAX_SIG, sizeof(struct event*));
        if(!base->signals) {
                event_base_free(base);
                return NULL;
        }
        base->tcp_stickies = 0;
        base->tcp_reinvigorated = 0;
        verbose(VERB_CLIENT, "winsock_event inited");
        return base;
}

const char *event_get_version(void)
{
        return "winsock-event-"PACKAGE_VERSION;
}

const char *event_get_method(void)
{
        return "WSAWaitForMultipleEvents";
}

/** call timeouts handlers, and return how long to wait for next one or -1 */
static void handle_timeouts(struct event_base* base, struct timeval* now,
        struct timeval* wait)
{
        struct event* p;
#ifndef S_SPLINT_S
        wait->tv_sec = (time_t)-1;
#endif
        verbose(VERB_CLIENT, "winsock_event handle_timeouts");

        while((rbnode_type*)(p = (struct event*)rbtree_first(base->times))
                !=RBTREE_NULL) {
#ifndef S_SPLINT_S
                if(p->ev_timeout.tv_sec > now->tv_sec ||
                        (p->ev_timeout.tv_sec==now->tv_sec &&
                        p->ev_timeout.tv_usec > now->tv_usec)) {
                        /* there is a next larger timeout. wait for it */
                        wait->tv_sec = p->ev_timeout.tv_sec - now->tv_sec;
                        if(now->tv_usec > p->ev_timeout.tv_usec) {
                                wait->tv_sec--;
                                wait->tv_usec = 1000000 - (now->tv_usec -
                                        p->ev_timeout.tv_usec);
                        } else {
                                wait->tv_usec = p->ev_timeout.tv_usec
                                        - now->tv_usec;
                        }
                        verbose(VERB_CLIENT, "winsock_event wait=" ARG_LL "d.%6.6d",
                                (long long)wait->tv_sec, (int)wait->tv_usec);
                        return;
                }
#endif
                /* event times out, remove it */
                (void)rbtree_delete(base->times, p);
                p->ev_events &= ~EV_TIMEOUT;
                fptr_ok(fptr_whitelist_event(p->ev_callback));
                (*p->ev_callback)(p->ev_fd, EV_TIMEOUT, p->ev_arg);
        }
        verbose(VERB_CLIENT, "winsock_event wait=(-1)");
}

/** handle is_signal events and see if signalled */
static void handle_signal(struct event* ev)
{
        DWORD ret;
        log_assert(ev->is_signal && ev->hEvent);
        /* see if the event is signalled */
        ret = WSAWaitForMultipleEvents(1, &ev->hEvent, 0 /* any object */,
                0 /* return immediately */, 0 /* not alertable for IOcomple*/);
        if(ret == WSA_WAIT_IO_COMPLETION || ret == WSA_WAIT_FAILED) {
                log_err("WSAWaitForMultipleEvents(signal) failed: %s",
                        wsa_strerror(WSAGetLastError()));
                return;
        }
        if(ret == WSA_WAIT_TIMEOUT) {
                /* not signalled */
                return;
        }

        /* reset the signal */
        if(!WSAResetEvent(ev->hEvent))
                log_err("WSAResetEvent failed: %s",
                        wsa_strerror(WSAGetLastError()));
        /* do the callback (which may set the signal again) */
        fptr_ok(fptr_whitelist_event(ev->ev_callback));
        (*ev->ev_callback)(ev->ev_fd, ev->ev_events, ev->ev_arg);
}

/** call select and callbacks for that */
static int handle_select(struct event_base* base, struct timeval* wait)
{
        DWORD timeout = 0; /* in milliseconds */        
        DWORD ret;
        struct event* eventlist[WSK_MAX_ITEMS];
        WSANETWORKEVENTS netev;
        int i, numwait = 0, startidx = 0, was_timeout = 0;
        int newstickies = 0;
        struct timeval nultm;

        verbose(VERB_CLIENT, "winsock_event handle_select");

#ifndef S_SPLINT_S
        if(wait->tv_sec==(time_t)-1)
                wait = NULL;
        if(wait)
                timeout = wait->tv_sec*1000 + wait->tv_usec/1000;
        if(base->tcp_stickies) {
                wait = &nultm;
                nultm.tv_sec = 0;
                nultm.tv_usec = 0;
                timeout = 0; /* no waiting, we have sticky events */
        }
#endif

        /* prepare event array */
        for(i=0; i<base->max; i++) {
                if(base->items[i]->ev_fd == -1 && !base->items[i]->is_signal)
                        continue; /* skip timer only events */
                eventlist[numwait] = base->items[i];
                base->waitfor[numwait++] = base->items[i]->hEvent;
                if(numwait == WSK_MAX_ITEMS)
                        break; /* sanity check */
        }
        log_assert(numwait <= WSA_MAXIMUM_WAIT_EVENTS);
        verbose(VERB_CLIENT, "winsock_event bmax=%d numwait=%d wait=%s "
                "timeout=%d", base->max, numwait, (wait?"<wait>":"<null>"),
                (int)timeout);

        /* do the wait */
        if(numwait == 0) {
                /* WSAWaitFor.. doesn't like 0 event objects */
                if(wait) {
                        Sleep(timeout);
                }
                was_timeout = 1;
        } else {
                ret = WSAWaitForMultipleEvents(numwait, base->waitfor,
                        0 /* do not wait for all, just one will do */,
                        wait?timeout:WSA_INFINITE,
                        0); /* we are not alertable (IO completion events) */
                if(ret == WSA_WAIT_IO_COMPLETION) {
                        log_err("WSAWaitForMultipleEvents failed: WSA_WAIT_IO_COMPLETION");
                        return -1;
                } else if(ret == WSA_WAIT_FAILED) {
                        log_err("WSAWaitForMultipleEvents failed: %s", 
                                wsa_strerror(WSAGetLastError()));
                        return -1;
                } else if(ret == WSA_WAIT_TIMEOUT) {
                        was_timeout = 1;
                } else
                        startidx = ret - WSA_WAIT_EVENT_0;
        }
        verbose(VERB_CLIENT, "winsock_event wake was_timeout=%d startidx=%d", 
                was_timeout, startidx);

        /* get new time after wait */
        if(settime(base) < 0)
               return -1;

        /* callbacks */
        if(base->tcp_stickies)
                startidx = 0; /* process all events, some are sticky */
        for(i=startidx; i<numwait; i++)
                eventlist[i]->just_checked = 1;

        verbose(VERB_CLIENT, "winsock_event signals");
        for(i=startidx; i<numwait; i++) {
                if(!base->waitfor[i])
                        continue; /* was deleted */
                if(eventlist[i]->is_signal) {
                        eventlist[i]->just_checked = 0;
                        handle_signal(eventlist[i]);
                }
        }
        /* early exit - do not process network, exit quickly */
        if(base->need_to_exit)
                return 0;

        verbose(VERB_CLIENT, "winsock_event net");
        for(i=startidx; i<numwait; i++) {
                short bits = 0;
                /* eventlist[i] fired */
                /* see if eventlist[i] is still valid and just checked from
                 * WSAWaitForEvents */
                if(!base->waitfor[i])
                        continue; /* was deleted */
                if(!eventlist[i]->just_checked)
                        continue; /* added by other callback */
                if(eventlist[i]->is_signal)
                        continue; /* not a network event at all */
                eventlist[i]->just_checked = 0;

                if(WSAEnumNetworkEvents(eventlist[i]->ev_fd, 
                        base->waitfor[i], /* reset the event handle */
                        /*NULL,*/ /* do not reset the event handle */
                        &netev) != 0) {
                        log_err("WSAEnumNetworkEvents failed: %s", 
                                wsa_strerror(WSAGetLastError()));
                        return -1;
                }
                if((netev.lNetworkEvents & FD_READ)) {
                        if(netev.iErrorCode[FD_READ_BIT] != 0)
                                verbose(VERB_ALGO, "FD_READ_BIT error: %s",
                                wsa_strerror(netev.iErrorCode[FD_READ_BIT]));
                        bits |= EV_READ;
                }
                if((netev.lNetworkEvents & FD_WRITE)) {
                        if(netev.iErrorCode[FD_WRITE_BIT] != 0)
                                verbose(VERB_ALGO, "FD_WRITE_BIT error: %s",
                                wsa_strerror(netev.iErrorCode[FD_WRITE_BIT]));
                        bits |= EV_WRITE;
                }
                if((netev.lNetworkEvents & FD_CONNECT)) {
                        if(netev.iErrorCode[FD_CONNECT_BIT] != 0)
                                verbose(VERB_ALGO, "FD_CONNECT_BIT error: %s",
                                wsa_strerror(netev.iErrorCode[FD_CONNECT_BIT]));
                        bits |= EV_READ;
                        bits |= EV_WRITE;
                }
                if((netev.lNetworkEvents & FD_ACCEPT)) {
                        if(netev.iErrorCode[FD_ACCEPT_BIT] != 0)
                                verbose(VERB_ALGO, "FD_ACCEPT_BIT error: %s",
                                wsa_strerror(netev.iErrorCode[FD_ACCEPT_BIT]));
                        bits |= EV_READ;
                }
                if((netev.lNetworkEvents & FD_CLOSE)) {
                        if(netev.iErrorCode[FD_CLOSE_BIT] != 0)
                                verbose(VERB_ALGO, "FD_CLOSE_BIT error: %s",
                                wsa_strerror(netev.iErrorCode[FD_CLOSE_BIT]));
                        bits |= EV_READ;
                        bits |= EV_WRITE;
                }
                if(eventlist[i]->is_tcp && eventlist[i]->stick_events) {
                        verbose(VERB_ALGO, "winsock %d pass sticky %s%s",
                                eventlist[i]->ev_fd,
                                (eventlist[i]->old_events&EV_READ)?"EV_READ":"",
                                (eventlist[i]->old_events&EV_WRITE)?"EV_WRITE":"");
                        bits |= eventlist[i]->old_events;
                }
                if(eventlist[i]->is_tcp && bits) {
                        eventlist[i]->old_events = bits;
                        eventlist[i]->stick_events = 1;
                        if((eventlist[i]->ev_events & bits)) {
                                newstickies = 1;
                        }
                        verbose(VERB_ALGO, "winsock %d store sticky %s%s",
                                eventlist[i]->ev_fd,
                                (eventlist[i]->old_events&EV_READ)?"EV_READ":"",
                                (eventlist[i]->old_events&EV_WRITE)?"EV_WRITE":"");
                }
                if((bits & eventlist[i]->ev_events)) {
                        verbose(VERB_ALGO, "winsock event callback %p fd=%d "
                                "%s%s%s%s%s ; %s%s%s", 
                                eventlist[i], eventlist[i]->ev_fd,
                                (netev.lNetworkEvents&FD_READ)?" FD_READ":"",
                                (netev.lNetworkEvents&FD_WRITE)?" FD_WRITE":"",
                                (netev.lNetworkEvents&FD_CONNECT)?
                                        " FD_CONNECT":"",
                                (netev.lNetworkEvents&FD_ACCEPT)?
                                        " FD_ACCEPT":"",
                                (netev.lNetworkEvents&FD_CLOSE)?" FD_CLOSE":"",
                                (bits&EV_READ)?" EV_READ":"",
                                (bits&EV_WRITE)?" EV_WRITE":"",
                                (bits&EV_TIMEOUT)?" EV_TIMEOUT":"");
                                
                        fptr_ok(fptr_whitelist_event(
                                eventlist[i]->ev_callback));
                        (*eventlist[i]->ev_callback)(eventlist[i]->ev_fd,
                                bits & eventlist[i]->ev_events, 
                                eventlist[i]->ev_arg);
                }
                if(eventlist[i]->is_tcp && bits)
                        verbose(VERB_ALGO, "winsock %d got sticky %s%s",
                                eventlist[i]->ev_fd,
                                (eventlist[i]->old_events&EV_READ)?"EV_READ":"",
                                (eventlist[i]->old_events&EV_WRITE)?"EV_WRITE":"");
        }
        verbose(VERB_CLIENT, "winsock_event net");
        if(base->tcp_reinvigorated) {
                verbose(VERB_CLIENT, "winsock_event reinvigorated");
                base->tcp_reinvigorated = 0;
                newstickies = 1;
        }
        base->tcp_stickies = newstickies;
        verbose(VERB_CLIENT, "winsock_event handle_select end");
        return 0;
}

int event_base_dispatch(struct event_base *base)
{
        struct timeval wait;
        if(settime(base) < 0)
                return -1;
        while(!base->need_to_exit)
        {
                /* see if timeouts need handling */
                handle_timeouts(base, base->time_tv, &wait);
                if(base->need_to_exit)
                        return 0;
                /* do select */
                if(handle_select(base, &wait) < 0) {
                        if(base->need_to_exit)
                                return 0;
                        return -1;
                }
        }
        return 0;
}

int event_base_loopexit(struct event_base *base, 
        struct timeval * ATTR_UNUSED(tv))
{
        verbose(VERB_CLIENT, "winsock_event loopexit");
        base->need_to_exit = 1;
        return 0;
}

void event_base_free(struct event_base *base)
{
        verbose(VERB_CLIENT, "winsock_event event_base_free");
        if(!base)
                return;
        free(base->items);
        free(base->times);
        free(base->signals);
        free(base);
}

void event_set(struct event *ev, int fd, short bits, 
        void (*cb)(int, short, void *), void *arg)
{
        ev->node.key = ev;
        ev->ev_fd = fd;
        ev->ev_events = bits;
        ev->ev_callback = cb;
        fptr_ok(fptr_whitelist_event(ev->ev_callback));
        ev->ev_arg = arg;
        ev->just_checked = 0;
        ev->added = 0;
}

int event_base_set(struct event_base *base, struct event *ev)
{
        ev->ev_base = base;
        ev->old_events = 0;
        ev->stick_events = 0;
        ev->added = 0;
        return 0;
}

int event_add(struct event *ev, struct timeval *tv)
{
        verbose(VERB_ALGO, "event_add %p added=%d fd=%d tv=" ARG_LL "d %s%s%s", 
                ev, ev->added, ev->ev_fd, 
                (tv?(long long)tv->tv_sec*1000+(long long)tv->tv_usec/1000:-1),
                (ev->ev_events&EV_READ)?" EV_READ":"",
                (ev->ev_events&EV_WRITE)?" EV_WRITE":"",
                (ev->ev_events&EV_TIMEOUT)?" EV_TIMEOUT":"");
        if(ev->added)
                event_del(ev);
        log_assert(ev->ev_fd==-1 || find_fd(ev->ev_base, ev->ev_fd) == -1);
        ev->is_tcp = 0;
        ev->is_signal = 0;
        ev->just_checked = 0;

        if((ev->ev_events&(EV_READ|EV_WRITE)) && ev->ev_fd != -1) {
                BOOL b=0;
                int t, l;
                long events = 0;

                if(ev->ev_base->max == ev->ev_base->cap)
                        return -1;
                ev->idx = ev->ev_base->max++;
                ev->ev_base->items[ev->idx] = ev;

                if( (ev->ev_events&EV_READ) )
                        events |= FD_READ;
                if( (ev->ev_events&EV_WRITE) )
                        events |= FD_WRITE;
                l = sizeof(t);
                if(getsockopt(ev->ev_fd, SOL_SOCKET, SO_TYPE,
                        (void*)&t, &l) != 0)
                        log_err("getsockopt(SO_TYPE) failed: %s",
                                wsa_strerror(WSAGetLastError()));
                if(t == SOCK_STREAM) {
                        /* TCP socket */
                        ev->is_tcp = 1;
                        events |= FD_CLOSE;
                        if( (ev->ev_events&EV_WRITE) )
                                events |= FD_CONNECT;
                        l = sizeof(b);
                        if(getsockopt(ev->ev_fd, SOL_SOCKET, SO_ACCEPTCONN,
                                (void*)&b, &l) != 0)
                                log_err("getsockopt(SO_ACCEPTCONN) failed: %s",
                                        wsa_strerror(WSAGetLastError()));
                        if(b) /* TCP accept socket */
                                events |= FD_ACCEPT;
                }
                ev->hEvent = WSACreateEvent();
                if(ev->hEvent == WSA_INVALID_EVENT)
                        log_err("WSACreateEvent failed: %s",
                                wsa_strerror(WSAGetLastError()));
                /* automatically sets fd to nonblocking mode.
                 * nonblocking cannot be disabled, until wsaES(fd, NULL, 0) */
                if(WSAEventSelect(ev->ev_fd, ev->hEvent, events) != 0) {
                        log_err("WSAEventSelect failed: %s",
                                wsa_strerror(WSAGetLastError()));
                }
                if(ev->is_tcp && ev->stick_events && 
                        (ev->ev_events & ev->old_events)) {
                        /* go to processing the sticky event right away */
                        ev->ev_base->tcp_reinvigorated = 1;
                }
        }

        if(tv && (ev->ev_events&EV_TIMEOUT)) {
#ifndef S_SPLINT_S
                struct timeval *now = ev->ev_base->time_tv;
                ev->ev_timeout.tv_sec = tv->tv_sec + now->tv_sec;
                ev->ev_timeout.tv_usec = tv->tv_usec + now->tv_usec;
                while(ev->ev_timeout.tv_usec >= 1000000) {
                        ev->ev_timeout.tv_usec -= 1000000;
                        ev->ev_timeout.tv_sec++;
                }
#endif
                (void)rbtree_insert(ev->ev_base->times, &ev->node);
        }
        ev->added = 1;
        return 0;
}

int event_del(struct event *ev)
{
        verbose(VERB_ALGO, "event_del %p added=%d fd=%d tv=" ARG_LL "d %s%s%s", 
                ev, ev->added, ev->ev_fd, 
                (ev->ev_events&EV_TIMEOUT)?(long long)ev->ev_timeout.tv_sec*1000+
                (long long)ev->ev_timeout.tv_usec/1000:-1,
                (ev->ev_events&EV_READ)?" EV_READ":"",
                (ev->ev_events&EV_WRITE)?" EV_WRITE":"",
                (ev->ev_events&EV_TIMEOUT)?" EV_TIMEOUT":"");
        if(!ev->added)
                return 0;
        log_assert(ev->added);
        if((ev->ev_events&EV_TIMEOUT))
                (void)rbtree_delete(ev->ev_base->times, &ev->node);
        if((ev->ev_events&(EV_READ|EV_WRITE)) && ev->ev_fd != -1) {
                log_assert(ev->ev_base->max > 0);
                /* remove item and compact the list */
                ev->ev_base->items[ev->idx] = 
                        ev->ev_base->items[ev->ev_base->max-1];
                ev->ev_base->items[ev->ev_base->max-1] = NULL;
                ev->ev_base->max--;
                if(ev->idx < ev->ev_base->max)
                        ev->ev_base->items[ev->idx]->idx = ev->idx;
                zero_waitfor(ev->ev_base->waitfor, ev->hEvent);

                if(WSAEventSelect(ev->ev_fd, ev->hEvent, 0) != 0)
                        log_err("WSAEventSelect(disable) failed: %s",
                                wsa_strerror(WSAGetLastError()));
                if(!WSACloseEvent(ev->hEvent))
                        log_err("WSACloseEvent failed: %s",
                                wsa_strerror(WSAGetLastError()));
        }
        ev->just_checked = 0;
        ev->added = 0;
        return 0;
}

/** which base gets to handle signals */
static struct event_base* signal_base = NULL;
/** signal handler */
static RETSIGTYPE sigh(int sig)
{
        struct event* ev;
        if(!signal_base || sig < 0 || sig >= MAX_SIG)
                return;
        ev = signal_base->signals[sig];
        if(!ev)
                return;
        fptr_ok(fptr_whitelist_event(ev->ev_callback));
        (*ev->ev_callback)(sig, EV_SIGNAL, ev->ev_arg);
}

int signal_add(struct event *ev, struct timeval * ATTR_UNUSED(tv))
{
        if(ev->ev_fd == -1 || ev->ev_fd >= MAX_SIG)
                return -1;
        signal_base = ev->ev_base;
        ev->ev_base->signals[ev->ev_fd] = ev;
        ev->added = 1;
        if(signal(ev->ev_fd, sigh) == SIG_ERR) {
                return -1;
        }
        return 0;
}

int signal_del(struct event *ev)
{
        if(ev->ev_fd == -1 || ev->ev_fd >= MAX_SIG)
                return -1;
        ev->ev_base->signals[ev->ev_fd] = NULL;
        ev->added = 0;
        return 0;
}

void winsock_tcp_wouldblock(struct event* ev, int eventbits)
{
        verbose(VERB_ALGO, "winsock: tcp wouldblock %s", 
                eventbits==EV_READ?"EV_READ":"EV_WRITE");
        ev->old_events &= (~eventbits);
        if(ev->old_events == 0)
                ev->stick_events = 0;
                /* in case this is the last sticky event, we could
                 * possibly run an empty handler loop to reset the base
                 * tcp_stickies variable 
                 */
}

int winsock_register_wsaevent(struct event_base* base, struct event* ev,
        WSAEVENT wsaevent, void (*cb)(int, short, void*), void* arg)
{
        if(base->max == base->cap)
                return 0;
        memset(ev, 0, sizeof(*ev));
        ev->ev_fd = -1;
        ev->ev_events = EV_READ;
        ev->ev_callback = cb;
        ev->ev_arg = arg;
        ev->is_signal = 1;
        ev->hEvent = wsaevent;
        ev->added = 1;
        ev->ev_base = base;
        ev->idx = ev->ev_base->max++;
        ev->ev_base->items[ev->idx] = ev;
        return 1;
}

void winsock_unregister_wsaevent(struct event* ev)
{
        if(!ev || !ev->added) return;
        log_assert(ev->added && ev->ev_base->max > 0)
        /* remove item and compact the list */
        ev->ev_base->items[ev->idx] = ev->ev_base->items[ev->ev_base->max-1];
        ev->ev_base->items[ev->ev_base->max-1] = NULL;
        ev->ev_base->max--;
        if(ev->idx < ev->ev_base->max)
                ev->ev_base->items[ev->idx]->idx = ev->idx;
        ev->added = 0;
}

#else /* USE_WINSOCK */
/** symbol so this codefile defines symbols. pleasing ranlib on OSX 10.5 */
int winsock_unused_symbol = 1;
#endif /* USE_WINSOCK */