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kc3-lang/libevent/event.c

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  • Author : Nick Mathewson
    Date : 2009-04-17 17:22:32
    Hash : d047b323
    Message : Increment version to 2.0.1-alpha, and add a numeric version facility svn:r1193

  • event.c
  • /*
     * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
     * Copyright (c) 2007-2009 Niels Provos and Nick Mathewson
     *
     * 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. 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.
     * 3. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * 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.
     */
    #ifdef HAVE_CONFIG_H
    #include "event-config.h"
    #endif
    
    #ifdef WIN32
    #include <winsock2.h>
    #define WIN32_LEAN_AND_MEAN
    #include <windows.h>
    #undef WIN32_LEAN_AND_MEAN
    #endif
    #include <sys/types.h>
    #ifndef WIN32
    #ifdef _EVENT_HAVE_SYS_TIME_H
    #include <sys/time.h>
    #else
    #include <sys/_time.h>
    #endif
    #endif
    #include <sys/queue.h>
    #ifdef _EVENT_HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #include <stdio.h>
    #include <stdlib.h>
    #ifdef _EVENT_HAVE_UNISTD_H
    #include <unistd.h>
    #endif
    #ifdef _EVENT_HAVE_SYS_EVENTFD_H
    #include <sys/eventfd.h>
    #endif
    #include <ctype.h>
    #include <errno.h>
    #include <signal.h>
    #include <string.h>
    #include <assert.h>
    #include <time.h>
    
    #include "event2/event.h"
    #include "event2/event_struct.h"
    #include "event2/event_compat.h"
    #include "event-internal.h"
    #include "defer-internal.h"
    #include "evthread-internal.h"
    #include "event2/thread.h"
    #include "event2/util.h"
    #include "log-internal.h"
    #include "evmap-internal.h"
    
    #ifdef _EVENT_HAVE_EVENT_PORTS
    extern const struct eventop evportops;
    #endif
    #ifdef _EVENT_HAVE_SELECT
    extern const struct eventop selectops;
    #endif
    #ifdef _EVENT_HAVE_POLL
    extern const struct eventop pollops;
    #endif
    #ifdef _EVENT_HAVE_EPOLL
    extern const struct eventop epollops;
    #endif
    #ifdef _EVENT_HAVE_WORKING_KQUEUE
    extern const struct eventop kqops;
    #endif
    #ifdef _EVENT_HAVE_DEVPOLL
    extern const struct eventop devpollops;
    #endif
    #ifdef WIN32
    extern const struct eventop win32ops;
    #endif
    
    /* In order of preference */
    static const struct eventop *eventops[] = {
    #ifdef _EVENT_HAVE_EVENT_PORTS
    	&evportops,
    #endif
    #ifdef _EVENT_HAVE_WORKING_KQUEUE
    	&kqops,
    #endif
    #ifdef _EVENT_HAVE_EPOLL
    	&epollops,
    #endif
    #ifdef _EVENT_HAVE_DEVPOLL
    	&devpollops,
    #endif
    #ifdef _EVENT_HAVE_POLL
    	&pollops,
    #endif
    #ifdef _EVENT_HAVE_SELECT
    	&selectops,
    #endif
    #ifdef WIN32
    	&win32ops,
    #endif
    	NULL
    };
    
    /* Global state */
    struct event_base *current_base = NULL;
    extern struct event_base *evsig_base;
    static int use_monotonic;
    
    /* Handle signals - This is a deprecated interface */
    int (*event_sigcb)(void);		/* Signal callback when gotsig is set */
    volatile sig_atomic_t event_gotsig;	/* Set in signal handler */
    
    /* Prototypes */
    static inline int event_add_internal(struct event *ev,
        const struct timeval *tv);
    static inline int event_del_internal(struct event *ev);
    static inline void event_active_internal(struct event *ev, int res,short count);
    
    static void	event_queue_insert(struct event_base *, struct event *, int);
    static void	event_queue_remove(struct event_base *, struct event *, int);
    static int	event_haveevents(struct event_base *);
    
    static void	event_process_active(struct event_base *);
    
    static int	timeout_next(struct event_base *, struct timeval **);
    static void	timeout_process(struct event_base *);
    static void	timeout_correct(struct event_base *, struct timeval *);
    
    static void	event_signal_closure(struct event_base *, struct event *ev);
    static void	event_persist_closure(struct event_base *, struct event *ev);
    
    static int evthread_notify_base(struct event_base *base);
    
    static void
    detect_monotonic(void)
    {
    #if defined(_EVENT_HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
    	struct timespec	ts;
    
    	if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
    		use_monotonic = 1;
    #endif
    }
    
    static int
    gettime(struct event_base *base, struct timeval *tp)
    {
    	if (base->tv_cache.tv_sec) {
    		*tp = base->tv_cache;
    		return (0);
    	}
    
    #if defined(_EVENT_HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
    	if (use_monotonic) {
    		struct timespec	ts;
    
    		if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
    			return (-1);
    
    		tp->tv_sec = ts.tv_sec;
    		tp->tv_usec = ts.tv_nsec / 1000;
    		return (0);
    	}
    #endif
    
    	return (evutil_gettimeofday(tp, NULL));
    }
    
    struct event_base *
    event_init(void)
    {
    	struct event_base *base = event_base_new();
    
    	if (base != NULL)
    		current_base = base;
    
    	return (base);
    }
    
    struct event_base *
    event_base_new(void)
    {
    	return (event_base_new_with_config(NULL));
    }
    
    static int
    event_config_is_avoided_method(struct event_config *cfg, const char *method)
    {
    	struct event_config_entry *entry;
    
    	TAILQ_FOREACH(entry, &cfg->entries, next) {
    		if (entry->avoid_method != NULL &&
    		    strcmp(entry->avoid_method, method) == 0)
    			return (1);
    	}
    
    	return (0);
    }
    
    static int
    event_is_method_disabled(const char *name)
    {
    	char environment[64];
    	int i;
    
    	evutil_snprintf(environment, sizeof(environment), "EVENT_NO%s", name);
    	for (i = 8; environment[i] != '\0'; ++i)
    		environment[i] = toupper(environment[i]);
    	return (getenv(environment) != NULL);
    }
    
    enum event_method_feature
    event_base_get_features(struct event_base *base)
    {
    	return base->evsel->features;
    }
    
    struct event_base *
    event_base_new_with_config(struct event_config *cfg)
    {
    	int i;
    	struct event_base *base;
    
    	if ((base = mm_calloc(1, sizeof(struct event_base))) == NULL)
    		event_err(1, "%s: calloc", __func__);
    
    	event_sigcb = NULL;
    	event_gotsig = 0;
    
    	detect_monotonic();
    	gettime(base, &base->event_tv);
    
    	min_heap_ctor(&base->timeheap);
    	TAILQ_INIT(&base->eventqueue);
    	TAILQ_INIT(&base->deferred_cb_list);
    	base->sig.ev_signal_pair[0] = -1;
    	base->sig.ev_signal_pair[1] = -1;
    
    	evmap_io_initmap(&base->io);
    	evmap_signal_initmap(&base->sigmap);
    
    	base->evbase = NULL;
    	for (i = 0; eventops[i] && !base->evbase; i++) {
    		if (cfg != NULL) {
    			/* determine if this backend should be avoided */
    			if (event_config_is_avoided_method(cfg,
    				eventops[i]->name))
    				continue;
    			if ((eventops[i]->features & cfg->require_features)
    			    != cfg->require_features)
    				continue;
    		}
    
    		/* also obey the environment variables */
    		if (event_is_method_disabled(eventops[i]->name))
    			continue;
    
    		base->evsel = eventops[i];
    
    		base->evbase = base->evsel->init(base);
    	}
    
    	if (base->evbase == NULL) {
    		if (cfg == NULL)
    			event_errx(1, "%s: no event mechanism available",
    			    __func__);
    		else {
    			event_base_free(base);
    			return NULL;
    		}
    	}
    
    	if (getenv("EVENT_SHOW_METHOD"))
    		event_msgx("libevent using: %s", base->evsel->name);
    
    	/* allocate a single active event queue */
    	event_base_priority_init(base, 1);
    
    	/* prepare for threading */
    	base->th_notify_fd[0] = -1;
    	base->th_notify_fd[1] = -1;
    
    	if (!cfg || !(cfg->flags & EVENT_BASE_FLAG_NOLOCK)) {
    		int r;
    		EVTHREAD_ALLOC_LOCK(base->th_base_lock);
    		r = evthread_make_base_notifiable(base);
    		if (r<0) {
    			event_base_free(base);
    			return NULL;
    		}
    	}
    
    	return (base);
    }
    
    void
    event_base_free(struct event_base *base)
    {
    	int i, n_deleted=0;
    	struct event *ev;
    
    	if (base == NULL && current_base)
    		base = current_base;
    	if (base == current_base)
    		current_base = NULL;
    
    	/* XXX(niels) - check for internal events first */
    	assert(base);
    
    	/* threading fds if we have them */
    	if (base->th_notify_fd[0] != -1) {
    		event_del(&base->th_notify);
    		EVUTIL_CLOSESOCKET(base->th_notify_fd[0]);
    		EVUTIL_CLOSESOCKET(base->th_notify_fd[1]);
    		base->th_notify_fd[0] = -1;
    		base->th_notify_fd[1] = -1;
    	}
    
    	EVTHREAD_FREE_LOCK(base->th_base_lock);
    
    	/* Delete all non-internal events. */
    	for (ev = TAILQ_FIRST(&base->eventqueue); ev; ) {
    		struct event *next = TAILQ_NEXT(ev, ev_next);
    		if (!(ev->ev_flags & EVLIST_INTERNAL)) {
    			event_del(ev);
    			++n_deleted;
    		}
    		ev = next;
    	}
    	while ((ev = min_heap_top(&base->timeheap)) != NULL) {
    		event_del(ev);
    		++n_deleted;
    	}
    
    	for (i = 0; i < base->nactivequeues; ++i) {
    		for (ev = TAILQ_FIRST(base->activequeues[i]); ev; ) {
    			struct event *next = TAILQ_NEXT(ev, ev_active_next);
    			if (!(ev->ev_flags & EVLIST_INTERNAL)) {
    				event_del(ev);
    				++n_deleted;
    			}
    			ev = next;
    		}
    	}
    
    	if (n_deleted)
    		event_debug(("%s: %d events were still set in base",
    			__func__, n_deleted));
    
    	if (base->evsel != NULL && base->evsel->dealloc != NULL)
    		base->evsel->dealloc(base);
    
    	for (i = 0; i < base->nactivequeues; ++i)
    		assert(TAILQ_EMPTY(base->activequeues[i]));
    
    	assert(min_heap_empty(&base->timeheap));
    	min_heap_dtor(&base->timeheap);
    
    	for (i = 0; i < base->nactivequeues; ++i)
    		mm_free(base->activequeues[i]);
    	mm_free(base->activequeues);
    
    	assert(TAILQ_EMPTY(&base->eventqueue));
    
    	evmap_io_clear(&base->io);
    	evmap_signal_clear(&base->sigmap);
    
    	mm_free(base);
    }
    
    /* reinitialized the event base after a fork */
    int
    event_reinit(struct event_base *base)
    {
    	const struct eventop *evsel = base->evsel;
    	int res = 0;
    	struct event *ev;
    
    	/* check if this event mechanism requires reinit */
    	if (!evsel->need_reinit)
    		return (0);
    
    	/* prevent internal delete */
    	if (base->sig.ev_signal_added) {
    		/* we cannot call event_del here because the base has
    		 * not been reinitialized yet. */
    		event_queue_remove(base, &base->sig.ev_signal,
    		    EVLIST_INSERTED);
    		if (base->sig.ev_signal.ev_flags & EVLIST_ACTIVE)
    			event_queue_remove(base, &base->sig.ev_signal,
    			    EVLIST_ACTIVE);
    		base->sig.ev_signal_added = 0;
    	}
    
    	if (base->evsel->dealloc != NULL)
    		base->evsel->dealloc(base);
    	base->evbase = evsel->init(base);
    	if (base->evbase == NULL)
    		event_errx(1, "%s: could not reinitialize event mechanism",
    		    __func__);
    
    	evmap_io_clear(&base->io);
    	evmap_signal_clear(&base->sigmap);
    
    	TAILQ_FOREACH(ev, &base->eventqueue, ev_next) {
    		if (ev->ev_events & (EV_READ|EV_WRITE)) {
    			if (evmap_io_add(base, ev->ev_fd, ev) == -1)
    				res = -1;
    		} else if (ev->ev_events & EV_SIGNAL) {
    			if (evmap_signal_add(base, ev->ev_fd, ev) == -1)
    				res = -1;
    		}
    	}
    
    	return (res);
    }
    
    const char **
    event_get_supported_methods(void)
    {
    	static const char **methods;
    	const struct eventop **method;
    	const char **tmp;
    	int i = 0, k;
    
    	/* count all methods */
    	for (method = &eventops[0]; *method != NULL; ++method) {
    		if (event_is_method_disabled((*method)->name))
    			continue;
    		++i;
    	}
    
    	/* allocate one more than we need for the NULL pointer */
    	tmp = mm_malloc((i + 1) * sizeof(char *));
    	if (tmp == NULL)
    		return (NULL);
    
    	/* populate the array with the supported methods */
    	for (k = 0, i = 0; eventops[k] != NULL; ++k) {
    		if (event_is_method_disabled(eventops[k]->name))
    			continue;
    		tmp[i++] = eventops[k]->name;
    	}
    	tmp[i] = NULL;
    
    	if (methods != NULL)
    		mm_free(methods);
    
    	methods = tmp;
    
    	return (methods);
    }
    
    struct event_config *
    event_config_new(void)
    {
    	struct event_config *cfg = mm_malloc(sizeof(*cfg));
    
    	if (cfg == NULL)
    		return (NULL);
    
    	TAILQ_INIT(&cfg->entries);
    	cfg->require_features = 0;
    
    	return (cfg);
    }
    
    static void
    event_config_entry_free(struct event_config_entry *entry)
    {
    	if (entry->avoid_method != NULL)
    		mm_free((char *)entry->avoid_method);
    	mm_free(entry);
    }
    
    void
    event_config_free(struct event_config *cfg)
    {
    	struct event_config_entry *entry;
    
    	while ((entry = TAILQ_FIRST(&cfg->entries)) != NULL) {
    		TAILQ_REMOVE(&cfg->entries, entry, next);
    		event_config_entry_free(entry);
    	}
    	mm_free(cfg);
    }
    
    int
    event_config_avoid_method(struct event_config *cfg, const char *method)
    {
    	struct event_config_entry *entry = mm_malloc(sizeof(*entry));
    	if (entry == NULL)
    		return (-1);
    
    	if ((entry->avoid_method = mm_strdup(method)) == NULL) {
    		mm_free(entry);
    		return (-1);
    	}
    
    	TAILQ_INSERT_TAIL(&cfg->entries, entry, next);
    
    	return (0);
    }
    
    int
    event_config_require_features(struct event_config *cfg,
                                  enum event_method_feature features)
    {
    	if (!cfg)
    		return (-1);
    	cfg->require_features = features;
    	return (0);
    }
    
    int
    event_priority_init(int npriorities)
    {
      return event_base_priority_init(current_base, npriorities);
    }
    
    int
    event_base_priority_init(struct event_base *base, int npriorities)
    {
    	int i;
    
    	if (base->event_count_active)
    		return (-1);
    
    	if (npriorities == base->nactivequeues)
    		return (0);
    
    	if (base->nactivequeues) {
    		for (i = 0; i < base->nactivequeues; ++i) {
    			mm_free(base->activequeues[i]);
    		}
    		mm_free(base->activequeues);
    	}
    
    	/* Allocate our priority queues */
    	base->nactivequeues = npriorities;
    	base->activequeues = (struct event_list **)mm_calloc(
    	    base->nactivequeues,
    	    npriorities * sizeof(struct event_list *));
    	if (base->activequeues == NULL)
    		event_err(1, "%s: calloc", __func__);
    
    	for (i = 0; i < base->nactivequeues; ++i) {
    		base->activequeues[i] = mm_malloc(sizeof(struct event_list));
    		if (base->activequeues[i] == NULL)
    			event_err(1, "%s: malloc", __func__);
    		TAILQ_INIT(base->activequeues[i]);
    	}
    
    	return (0);
    }
    
    int
    event_haveevents(struct event_base *base)
    {
    	return (base->event_count > 0);
    }
    
    static void
    event_persist_closure(struct event_base *base, struct event *ev)
    {
    	/* reschedule the persistent event if we have a timeout */
    	if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec)
    		event_add(ev, &ev->ev_io_timeout);
    	(*ev->ev_callback)((int)ev->ev_fd, ev->ev_res, ev->ev_arg);
    }
    
    static void
    event_signal_closure(struct event_base *base, struct event *ev)
    {
    	short ncalls;
    
    	/* Allows deletes to work */
    	ncalls = ev->ev_ncalls;
    	ev->ev_pncalls = &ncalls;
    	while (ncalls) {
    		ncalls--;
    		ev->ev_ncalls = ncalls;
    		(*ev->ev_callback)((int)ev->ev_fd, ev->ev_res, ev->ev_arg);
    		if (event_gotsig || base->event_break)
    			return;
    	}
    }
    
    /*
      Helper for event_process_active to process all the events in a single queue,
      releasing the lock as we go.  This function requires that the lock be held
      when it's invoked.  Returns -1 if we get a signal or an event_break that
      means we should stop processing any active events now.  Otherwise returns
      the number of non-internal events that we processed.
    */
    static int
    event_process_active_single_queue(struct event_base *base,
        struct event_list *activeq)
    {
    	struct event *ev;
    	int count = 0;
    
    	assert(activeq != NULL);
    
    	for (ev = TAILQ_FIRST(activeq); ev; ev = TAILQ_FIRST(activeq)) {
    		if (ev->ev_events & EV_PERSIST)
    			event_queue_remove(base, ev, EVLIST_ACTIVE);
    		else
    			event_del_internal(ev);
    		if (!(ev->ev_flags & EVLIST_INTERNAL))
    			++count;
    
    		event_debug((
    			 "event_process_active: event: %p, %s%scall %p",
    			ev,
    			ev->ev_res & EV_READ ? "EV_READ " : " ",
    			ev->ev_res & EV_WRITE ? "EV_WRITE " : " ",
    			ev->ev_callback));
    
    		EVBASE_RELEASE_LOCK(base,
    		    EVTHREAD_WRITE, th_base_lock);
    
    		if (ev->ev_closure != NULL)
    			(*ev->ev_closure)(base, ev);
    		else
    			(*ev->ev_callback)(
    				(int)ev->ev_fd, ev->ev_res, ev->ev_arg);
    		if (event_gotsig || base->event_break)
    			return -1;
    		EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	}
    	return count;
    }
    
    static int
    event_process_deferred_callbacks(struct event_base *base)
    {
    	int count = 0;
    	struct deferred_cb *cb;
    
    	while ((cb = TAILQ_FIRST(&base->deferred_cb_list))) {
    		cb->queued = 0;
    		TAILQ_REMOVE(&base->deferred_cb_list, cb, cb_next);
    		--base->event_count_active;
    		EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    
    		cb->cb(cb, cb->arg);
    		++count;
    		if (event_gotsig || base->event_break)
    			return -1;
    
    		EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	}
    	return count;
    }
    
    /*
     * Active events are stored in priority queues.  Lower priorities are always
     * process before higher priorities.  Low priority events can starve high
     * priority ones.
     */
    
    static void
    event_process_active(struct event_base *base)
    {
    	struct event_list *activeq = NULL;
    	int i, c;
    
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    
    	for (i = 0; i < base->nactivequeues; ++i) {
    		if (TAILQ_FIRST(base->activequeues[i]) != NULL) {
    			activeq = base->activequeues[i];
    			c = event_process_active_single_queue(base, activeq);
    			if (c < 0)
    				return; /* already unlocked */
    			else if (c > 0)
    				break; /* Processed a real event; do not
    					* consider lower-priority events */
    			/* If we get here, all of the events we processed
    			 * were internal.  Continue. */
    		}
    	}
    
    	event_process_deferred_callbacks(base);
    
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    }
    
    /*
     * Wait continously for events.  We exit only if no events are left.
     */
    
    int
    event_dispatch(void)
    {
    	return (event_loop(0));
    }
    
    int
    event_base_dispatch(struct event_base *event_base)
    {
      return (event_base_loop(event_base, 0));
    }
    
    const char *
    event_base_get_method(struct event_base *base)
    {
    	assert(base);
    	return (base->evsel->name);
    }
    
    static void
    event_loopexit_cb(evutil_socket_t fd, short what, void *arg)
    {
    	struct event_base *base = arg;
    	base->event_gotterm = 1;
    }
    
    /* not thread safe */
    int
    event_loopexit(const struct timeval *tv)
    {
    	return (event_once(-1, EV_TIMEOUT, event_loopexit_cb,
    		    current_base, tv));
    }
    
    int
    event_base_loopexit(struct event_base *event_base, const struct timeval *tv)
    {
    	return (event_base_once(event_base, -1, EV_TIMEOUT, event_loopexit_cb,
    		    event_base, tv));
    }
    
    int
    event_loopbreak(void)
    {
    	return (event_base_loopbreak(current_base));
    }
    
    int
    event_base_loopbreak(struct event_base *event_base)
    {
    	if (event_base == NULL)
    		return (-1);
    
    	EVBASE_ACQUIRE_LOCK(event_base, EVTHREAD_WRITE, th_base_lock);
    	event_base->event_break = 1;
    	EVBASE_RELEASE_LOCK(event_base, EVTHREAD_WRITE, th_base_lock);
    
    	if (!EVBASE_IN_THREAD(event_base)) {
    		return evthread_notify_base(event_base);
    	} else {
    		return (0);
    	}
    }
    
    
    
    /* not thread safe */
    
    int
    event_loop(int flags)
    {
    	return event_base_loop(current_base, flags);
    }
    
    int
    event_base_loop(struct event_base *base, int flags)
    {
    	const struct eventop *evsel = base->evsel;
    	struct timeval tv;
    	struct timeval *tv_p;
    	int res, done;
    
    	/* clear time cache */
    	base->tv_cache.tv_sec = 0;
    
    	if (base->sig.ev_signal_added)
    		evsig_base = base;
    	done = 0;
    
    #ifndef _EVENT_DISABLE_THREAD_SUPPORT
    	base->th_owner_id = EVTHREAD_GET_ID();
    #endif
    
    	while (!done) {
    		/* Terminate the loop if we have been asked to */
    		if (base->event_gotterm) {
    			base->event_gotterm = 0;
    			break;
    		}
    
    		if (base->event_break) {
    			base->event_break = 0;
    			break;
    		}
    
    		/* You cannot use this interface for multi-threaded apps */
    		while (event_gotsig) {
    			event_gotsig = 0;
    			if (event_sigcb) {
    				res = (*event_sigcb)();
    				if (res == -1) {
    					errno = EINTR;
    					return (-1);
    				}
    			}
    		}
    
    		timeout_correct(base, &tv);
    
    		tv_p = &tv;
    		if (!base->event_count_active && !(flags & EVLOOP_NONBLOCK)) {
    			timeout_next(base, &tv_p);
    		} else {
    			/*
    			 * if we have active events, we just poll new events
    			 * without waiting.
    			 */
    			evutil_timerclear(&tv);
    		}
    
    		/* If we have no events, we just exit */
    		if (!event_haveevents(base) && !base->event_count_active) {
    			event_debug(("%s: no events registered.", __func__));
    			return (1);
    		}
    
    		/* update last old time */
    		gettime(base, &base->event_tv);
    
    		/* clear time cache */
    		base->tv_cache.tv_sec = 0;
    
    		res = evsel->dispatch(base, tv_p);
    
    		if (res == -1)
    			return (-1);
    		gettime(base, &base->tv_cache);
    
    		timeout_process(base);
    
    		if (base->event_count_active) {
    			event_process_active(base);
    			if (!base->event_count_active && (flags & EVLOOP_ONCE))
    				done = 1;
    		} else if (flags & EVLOOP_NONBLOCK)
    			done = 1;
    	}
    
    	/* clear time cache */
    	base->tv_cache.tv_sec = 0;
    
    	event_debug(("%s: asked to terminate loop.", __func__));
    	return (0);
    }
    
    /* Sets up an event for processing once */
    
    struct event_once {
    	struct event ev;
    
    	void (*cb)(evutil_socket_t, short, void *);
    	void *arg;
    };
    
    /* One-time callback, it deletes itself */
    
    static void
    event_once_cb(evutil_socket_t fd, short events, void *arg)
    {
    	struct event_once *eonce = arg;
    
    	(*eonce->cb)(fd, events, eonce->arg);
    	mm_free(eonce);
    }
    
    /* not threadsafe, event scheduled once. */
    int
    event_once(evutil_socket_t fd, short events,
        void (*callback)(evutil_socket_t, short, void *),
    	void *arg, const struct timeval *tv)
    {
    	return event_base_once(current_base, fd, events, callback, arg, tv);
    }
    
    /* Schedules an event once */
    int
    event_base_once(struct event_base *base, evutil_socket_t fd, short events,
        void (*callback)(evutil_socket_t, short, void *),
    	void *arg, const struct timeval *tv)
    {
    	struct event_once *eonce;
    	struct timeval etv;
    	int res = 0;
    
    	/* We cannot support signals that just fire once */
    	if (events & EV_SIGNAL)
    		return (-1);
    
    	if ((eonce = mm_calloc(1, sizeof(struct event_once))) == NULL)
    		return (-1);
    
    	eonce->cb = callback;
    	eonce->arg = arg;
    
    	if (events == EV_TIMEOUT) {
    		if (tv == NULL) {
    			evutil_timerclear(&etv);
    			tv = &etv;
    		}
    
    		evtimer_assign(&eonce->ev, base, event_once_cb, eonce);
    	} else if (events & (EV_READ|EV_WRITE)) {
    		events &= EV_READ|EV_WRITE;
    
    		event_assign(&eonce->ev, base, fd, events, event_once_cb, eonce);
    	} else {
    		/* Bad event combination */
    		mm_free(eonce);
    		return (-1);
    	}
    
    	if (res == 0)
    		res = event_add(&eonce->ev, tv);
    	if (res != 0) {
    		mm_free(eonce);
    		return (res);
    	}
    
    	return (0);
    }
    
    void
    event_set(struct event *ev, evutil_socket_t fd, short events,
    	  void (*callback)(evutil_socket_t, short, void *), void *arg)
    {
    	/* Take the current base - caller needs to set the real base later */
    	ev->ev_base = current_base;
    
    	ev->ev_callback = callback;
    	ev->ev_arg = arg;
    	ev->ev_fd = fd;
    	ev->ev_events = events;
    	ev->ev_res = 0;
    	ev->ev_flags = EVLIST_INIT;
    	ev->ev_ncalls = 0;
    	ev->ev_pncalls = NULL;
    
    	if (events & EV_SIGNAL) {
    		if ((events & (EV_READ|EV_WRITE)) != 0)
    			event_errx(1, "%s: EV_SIGNAL incompatible use",
    			    __func__);
    		ev->ev_closure = event_signal_closure;
    	} else {
    		if (events & EV_PERSIST) {
    			timerclear(&ev->ev_io_timeout);
    			ev->ev_closure = event_persist_closure;
    		} else {
    			ev->ev_closure = NULL;
    		}
    	}
    
    	min_heap_elem_init(ev);
    
    	/* by default, we put new events into the middle priority */
    	if (current_base)
    		ev->ev_pri = current_base->nactivequeues/2;
    }
    
    int
    event_base_set(struct event_base *base, struct event *ev)
    {
    	/* Only innocent events may be assigned to a different base */
    	if (ev->ev_flags != EVLIST_INIT)
    		return (-1);
    
    	ev->ev_base = base;
    	ev->ev_pri = base->nactivequeues/2;
    
    	return (0);
    }
    
    void
    event_assign(struct event *ev, struct event_base *base, evutil_socket_t fd, short events, void (*cb)(evutil_socket_t, short, void *), void *arg)
    {
    	event_set(ev, fd, events, cb, arg);
    	if (base != NULL)
    		assert(event_base_set(base, ev) == 0);
    }
    
    struct event *
    event_new(struct event_base *base, evutil_socket_t fd, short events, void (*cb)(evutil_socket_t, short, void *), void *arg)
    {
    	struct event *ev;
    	ev = mm_malloc(sizeof(struct event));
    	if (ev == NULL)
    		return (NULL);
    	event_assign(ev, base, fd, events, cb, arg);
    
    	return (ev);
    }
    
    void
    event_free(struct event *ev)
    {
    	/* make sure that this event won't be coming back to haunt us. */
    	event_del(ev);
    	mm_free(ev);
    }
    
    /*
     * Set's the priority of an event - if an event is already scheduled
     * changing the priority is going to fail.
     */
    
    int
    event_priority_set(struct event *ev, int pri)
    {
    	if (ev->ev_flags & EVLIST_ACTIVE)
    		return (-1);
    	if (pri < 0 || pri >= ev->ev_base->nactivequeues)
    		return (-1);
    
    	ev->ev_pri = pri;
    
    	return (0);
    }
    
    /*
     * Checks if a specific event is pending or scheduled.
     */
    
    int
    event_pending(struct event *ev, short event, struct timeval *tv)
    {
    	struct timeval	now, res;
    	int flags = 0;
    
    	if (ev->ev_flags & EVLIST_INSERTED)
    		flags |= (ev->ev_events & (EV_READ|EV_WRITE|EV_SIGNAL));
    	if (ev->ev_flags & EVLIST_ACTIVE)
    		flags |= ev->ev_res;
    	if (ev->ev_flags & EVLIST_TIMEOUT)
    		flags |= EV_TIMEOUT;
    
    	event &= (EV_TIMEOUT|EV_READ|EV_WRITE|EV_SIGNAL);
    
    	/* See if there is a timeout that we should report */
    	if (tv != NULL && (flags & event & EV_TIMEOUT)) {
    		gettime(ev->ev_base, &now);
    		evutil_timersub(&ev->ev_timeout, &now, &res);
    		/* correctly remap to real time */
    		evutil_gettimeofday(&now, NULL);
    		evutil_timeradd(&now, &res, tv);
    	}
    
    	return (flags & event);
    }
    
    int
    _event_initialized(struct event *ev, int need_fd)
    {
    	if (!(ev->ev_flags & EVLIST_INIT))
    		return 0;
    #ifdef WIN32
    	/* XXX Is this actually a sensible thing to check? -NM */
    	if (need_fd && (ev)->ev_fd == (evutil_socket_t)INVALID_HANDLE_VALUE)
    		return 0;
    #endif
    	return 1;
    }
    
    evutil_socket_t
    event_get_fd(struct event *ev)
    {
    	return ev->ev_fd;
    }
    
    int
    event_add(struct event *ev, const struct timeval *tv)
    {
    	int res;
    
    	EVBASE_ACQUIRE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    
    	res = event_add_internal(ev, tv);
    
    	EVBASE_RELEASE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    
    	return (res);
    }
    
    static int
    evthread_notify_base_default(struct event_base *base)
    {
    	char buf[1];
    	int r;
    	buf[0] = (char) 0;
    #ifdef WIN32
    	r = send(base->th_notify_fd[1], buf, 1, 0);
    #else
    	r = write(base->th_notify_fd[1], buf, 1);
    #endif
    	return (r < 0) ? -1 : 0;
    }
    
    #if defined(_EVENT_HAVE_EVENTFD) && defined(_EVENT_HAVE_SYS_EVENTFD_H)
    static int
    evthread_notify_base_eventfd(struct event_base *base)
    {
    	ev_uint64_t msg = 1;
    	int r;
    	do {
    		r = write(base->th_notify_fd[0], (void*) &msg, sizeof(msg));
    	} while (r < 0 && errno == EAGAIN);
    
    	return (r < 0) ? -1 : 0;
    }
    #endif
    
    static int
    evthread_notify_base(struct event_base *base)
    {
    	if (!base->th_notify_fn)
    		return -1;
    	return base->th_notify_fn(base);
    }
    
    static inline int
    event_add_internal(struct event *ev, const struct timeval *tv)
    {
    	struct event_base *base = ev->ev_base;
    	int res = 0;
    
    	event_debug((
    		 "event_add: event: %p, %s%s%scall %p",
    		 ev,
    		 ev->ev_events & EV_READ ? "EV_READ " : " ",
    		 ev->ev_events & EV_WRITE ? "EV_WRITE " : " ",
    		 tv ? "EV_TIMEOUT " : " ",
    		 ev->ev_callback));
    
    	assert(!(ev->ev_flags & ~EVLIST_ALL));
    
    	/*
    	 * prepare for timeout insertion further below, if we get a
    	 * failure on any step, we should not change any state.
    	 */
    	if (tv != NULL && !(ev->ev_flags & EVLIST_TIMEOUT)) {
    		if (min_heap_reserve(&base->timeheap,
    			1 + min_heap_size(&base->timeheap)) == -1)
    			return (-1);  /* ENOMEM == errno */
    	}
    
    	if ((ev->ev_events & (EV_READ|EV_WRITE|EV_SIGNAL)) &&
    	    !(ev->ev_flags & (EVLIST_INSERTED|EVLIST_ACTIVE))) {
    		if (ev->ev_events & (EV_READ|EV_WRITE))
    			res = evmap_io_add(base, ev->ev_fd, ev);
    		else if (ev->ev_events & EV_SIGNAL)
    			res = evmap_signal_add(base, ev->ev_fd, ev);
    		if (res != -1)
    			event_queue_insert(base, ev, EVLIST_INSERTED);
    	}
    
    	/*
    	 * we should change the timout state only if the previous event
    	 * addition succeeded.
    	 */
    	if (res != -1 && tv != NULL) {
    		struct timeval now;
    
    		/*
    		 * for persistent timeout events, we remember the
    		 * timeout value and re-add the event.
    		 */
    		if (ev->ev_closure == event_persist_closure)
    			ev->ev_io_timeout = *tv;
    
    		/*
    		 * we already reserved memory above for the case where we
    		 * are not replacing an exisiting timeout.
    		 */
    		if (ev->ev_flags & EVLIST_TIMEOUT)
    			event_queue_remove(base, ev, EVLIST_TIMEOUT);
    
    		/* Check if it is active due to a timeout.  Rescheduling
    		 * this timeout before the callback can be executed
    		 * removes it from the active list. */
    		if ((ev->ev_flags & EVLIST_ACTIVE) &&
    		    (ev->ev_res & EV_TIMEOUT)) {
    			if (ev->ev_events & EV_SIGNAL) {
    				/* See if we are just active executing
    				 * this event in a loop
    				 */
    				if (ev->ev_ncalls && ev->ev_pncalls) {
    					/* Abort loop */
    					*ev->ev_pncalls = 0;
    				}
    			}
    
    			event_queue_remove(base, ev, EVLIST_ACTIVE);
    		}
    
    		gettime(base, &now);
    		evutil_timeradd(&now, tv, &ev->ev_timeout);
    
    		event_debug((
    			 "event_add: timeout in %d seconds, call %p",
    			 (int)tv->tv_sec, ev->ev_callback));
    
    		event_queue_insert(base, ev, EVLIST_TIMEOUT);
    	}
    
    	/* if we are not in the right thread, we need to wake up the loop */
    	if (res != -1 && !EVBASE_IN_THREAD(base))
    		evthread_notify_base(base);
    
    	return (res);
    }
    
    int
    event_del(struct event *ev)
    {
    	int res;
    
    	EVBASE_ACQUIRE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    
    	res = event_del_internal(ev);
    
    	EVBASE_RELEASE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    
    	return (res);
    }
    
    static inline int
    event_del_internal(struct event *ev)
    {
    	struct event_base *base;
    	int res = 0;
    
    	event_debug(("event_del: %p, callback %p",
    		 ev, ev->ev_callback));
    
    	/* An event without a base has not been added */
    	if (ev->ev_base == NULL)
    		return (-1);
    
    	base = ev->ev_base;
    
    	assert(!(ev->ev_flags & ~EVLIST_ALL));
    
    	/* See if we are just active executing this event in a loop */
    	if (ev->ev_events & EV_SIGNAL) {
    		if (ev->ev_ncalls && ev->ev_pncalls) {
    			/* Abort loop */
    			*ev->ev_pncalls = 0;
    		}
    	}
    
    	if (ev->ev_flags & EVLIST_TIMEOUT)
    		event_queue_remove(base, ev, EVLIST_TIMEOUT);
    
    	if (ev->ev_flags & EVLIST_ACTIVE)
    		event_queue_remove(base, ev, EVLIST_ACTIVE);
    
    	if (ev->ev_flags & EVLIST_INSERTED) {
    		event_queue_remove(base, ev, EVLIST_INSERTED);
    		if (ev->ev_events & (EV_READ|EV_WRITE))
    			res = evmap_io_del(base, ev->ev_fd, ev);
    		else
    			res = evmap_signal_del(base, ev->ev_fd, ev);
    	}
    
    	/* if we are not in the right thread, we need to wake up the loop */
    	if (res != -1 && !EVBASE_IN_THREAD(base))
    		evthread_notify_base(base);
    
    	return (res);
    }
    
    void
    event_active(struct event *ev, int res, short ncalls)
    {
    	EVBASE_ACQUIRE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    
    	event_active_internal(ev, res, ncalls);
    
    	EVBASE_RELEASE_LOCK(ev->ev_base, EVTHREAD_WRITE, th_base_lock);
    }
    
    
    static inline void
    event_active_internal(struct event *ev, int res, short ncalls)
    {
    	struct event_base *base;
    
    	/* We get different kinds of events, add them together */
    	if (ev->ev_flags & EVLIST_ACTIVE) {
    		ev->ev_res |= res;
    		return;
    	}
    
    	base = ev->ev_base;
    
    	ev->ev_res = res;
    
    	if (ev->ev_events & EV_SIGNAL) {
    		ev->ev_ncalls = ncalls;
    		ev->ev_pncalls = NULL;
    	}
    
    	event_queue_insert(base, ev, EVLIST_ACTIVE);
    }
    
    void
    event_deferred_cb_init(struct deferred_cb *cb, deferred_cb_fn fn, void *arg)
    {
    	memset(cb, 0, sizeof(struct deferred_cb));
    	cb->cb = fn;
    	cb->arg = arg;
    }
    
    void
    event_deferred_cb_cancel(struct event_base *base, struct deferred_cb *cb)
    {
    	if (!base)
    		base = current_base;
    
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	if (cb->queued) {
    		TAILQ_REMOVE(&base->deferred_cb_list, cb, cb_next);
    		--base->event_count_active;
    		cb->queued = 0;
    	}
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    }
    
    void
    event_deferred_cb_schedule(struct event_base *base, struct deferred_cb *cb)
    {
    	if (!base)
    		base = current_base;
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	if (!cb->queued) {
    		cb->queued = 1;
    		TAILQ_INSERT_TAIL(&base->deferred_cb_list, cb, cb_next);
    		++base->event_count_active;
    		if (!EVBASE_IN_THREAD(base))
    			evthread_notify_base(base);
    	}
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    }
    
    static int
    timeout_next(struct event_base *base, struct timeval **tv_p)
    {
    	struct timeval now;
    	struct event *ev;
    	struct timeval *tv = *tv_p;
    	int res = 0;
    
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	ev = min_heap_top(&base->timeheap);
    
    	if (ev == NULL) {
    		/* if no time-based events are active wait for I/O */
    		*tv_p = NULL;
    		goto out;
    	}
    
    	if (gettime(base, &now) == -1) {
    		res = -1;
    		goto out;
    	}
    
    	if (evutil_timercmp(&ev->ev_timeout, &now, <=)) {
    		evutil_timerclear(tv);
    		goto out;
    	}
    
    	evutil_timersub(&ev->ev_timeout, &now, tv);
    
    	assert(tv->tv_sec >= 0);
    	assert(tv->tv_usec >= 0);
    	event_debug(("timeout_next: in %d seconds", (int)tv->tv_sec));
    
    out:
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	return (res);
    }
    
    /*
     * Determines if the time is running backwards by comparing the current
     * time against the last time we checked.  Not needed when using clock
     * monotonic.
     */
    
    static void
    timeout_correct(struct event_base *base, struct timeval *tv)
    {
    	struct event **pev;
    	unsigned int size;
    	struct timeval off;
    
    	if (use_monotonic)
    		return;
    
    	/* Check if time is running backwards */
    	gettime(base, tv);
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    
    	if (evutil_timercmp(tv, &base->event_tv, >=)) {
    		base->event_tv = *tv;
    		EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    		return;
    	}
    
    	event_debug(("%s: time is running backwards, corrected",
    		    __func__));
    	evutil_timersub(&base->event_tv, tv, &off);
    
    	/*
    	 * We can modify the key element of the node without destroying
    	 * the key, beause we apply it to all in the right order.
    	 */
    	pev = base->timeheap.p;
    	size = base->timeheap.n;
    	for (; size-- > 0; ++pev) {
    		struct timeval *ev_tv = &(**pev).ev_timeout;
    		evutil_timersub(ev_tv, &off, ev_tv);
    	}
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    }
    
    static void
    timeout_process(struct event_base *base)
    {
    	struct timeval now;
    	struct event *ev;
    
    	EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    	if (min_heap_empty(&base->timeheap)) {
    		EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    		return;
    	}
    
    	gettime(base, &now);
    
    	while ((ev = min_heap_top(&base->timeheap))) {
    		if (evutil_timercmp(&ev->ev_timeout, &now, >))
    			break;
    
    		/* delete this event from the I/O queues */
    		event_del_internal(ev);
    
    		event_debug(("timeout_process: call %p",
    			 ev->ev_callback));
    		event_active_internal(ev, EV_TIMEOUT, 1);
    	}
    	EVBASE_RELEASE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
    }
    
    void
    event_queue_remove(struct event_base *base, struct event *ev, int queue)
    {
    	if (!(ev->ev_flags & queue))
    		event_errx(1, "%s: %p(fd %d) not on queue %x", __func__,
    			   ev, ev->ev_fd, queue);
    
    	if (~ev->ev_flags & EVLIST_INTERNAL)
    		base->event_count--;
    
    	ev->ev_flags &= ~queue;
    	switch (queue) {
    	case EVLIST_INSERTED:
    		TAILQ_REMOVE(&base->eventqueue, ev, ev_next);
    		break;
    	case EVLIST_ACTIVE:
    		base->event_count_active--;
    		TAILQ_REMOVE(base->activequeues[ev->ev_pri],
    		    ev, ev_active_next);
    		break;
    	case EVLIST_TIMEOUT:
    		min_heap_erase(&base->timeheap, ev);
    		break;
    	default:
    		event_errx(1, "%s: unknown queue %x", __func__, queue);
    	}
    }
    
    void
    event_queue_insert(struct event_base *base, struct event *ev, int queue)
    {
    	if (ev->ev_flags & queue) {
    		/* Double insertion is possible for active events */
    		if (queue & EVLIST_ACTIVE)
    			return;
    
    		event_errx(1, "%s: %p(fd %d) already on queue %x", __func__,
    			   ev, ev->ev_fd, queue);
    	}
    
    	if (~ev->ev_flags & EVLIST_INTERNAL)
    		base->event_count++;
    
    	ev->ev_flags |= queue;
    	switch (queue) {
    	case EVLIST_INSERTED:
    		TAILQ_INSERT_TAIL(&base->eventqueue, ev, ev_next);
    		break;
    	case EVLIST_ACTIVE:
    		base->event_count_active++;
    		TAILQ_INSERT_TAIL(base->activequeues[ev->ev_pri],
    		    ev,ev_active_next);
    		break;
    	case EVLIST_TIMEOUT: {
    		min_heap_push(&base->timeheap, ev);
    		break;
    	}
    	default:
    		event_errx(1, "%s: unknown queue %x", __func__, queue);
    	}
    }
    
    /* Functions for debugging */
    
    const char *
    event_get_version(void)
    {
    	return (_EVENT_VERSION);
    }
    
    ev_uint32_t
    event_get_version_number(void)
    {
    	return (_EVENT_NUMERIC_VERSION);
    }
    
    /*
     * No thread-safe interface needed - the information should be the same
     * for all threads.
     */
    
    const char *
    event_get_method(void)
    {
    	return (current_base->evsel->name);
    }
    
    #ifndef _EVENT_DISABLE_MM_REPLACEMENT
    static void *(*_mm_malloc_fn)(size_t sz) = NULL;
    static void *(*_mm_realloc_fn)(void *p, size_t sz) = NULL;
    static void (*_mm_free_fn)(void *p) = NULL;
    
    void *
    mm_malloc(size_t sz)
    {
    	if (_mm_malloc_fn)
    		return _mm_malloc_fn(sz);
    	else
    		return malloc(sz);
    }
    
    void *
    mm_calloc(size_t count, size_t size)
    {
    	if (_mm_malloc_fn) {
    		size_t sz = count * size;
    		void *p = _mm_malloc_fn(sz);
    		if (p)
    			memset(p, 0, sz);
    		return p;
    	} else
    		return calloc(count, size);
    }
    
    char *
    mm_strdup(const char *str)
    {
    	if (_mm_malloc_fn) {
    		size_t ln = strlen(str);
    		void *p = _mm_malloc_fn(ln+1);
    		if (p)
    			memcpy(p, str, ln+1);
    		return p;
    	} else
    #ifdef WIN32
    		return _strdup(str);
    #else
    		return strdup(str);
    #endif
    }
    
    void *
    mm_realloc(void *ptr, size_t sz)
    {
    	if (_mm_realloc_fn)
    		return _mm_realloc_fn(ptr, sz);
    	else
    		return realloc(ptr, sz);
    }
    
    void
    mm_free(void *ptr)
    {
    	if (_mm_free_fn)
    		_mm_free_fn(ptr);
    	else
    		free(ptr);
    }
    
    void
    event_set_mem_functions(void *(*malloc_fn)(size_t sz),
    			void *(*realloc_fn)(void *ptr, size_t sz),
    			void (*free_fn)(void *ptr))
    {
    	_mm_malloc_fn = malloc_fn;
    	_mm_realloc_fn = realloc_fn;
    	_mm_free_fn = free_fn;
    }
    #endif
    
    /* support for threading */
    void (*_evthread_locking_fn)(int mode, void *lock) = NULL;
    unsigned long (*_evthread_id_fn)(void) = NULL;
    void *(*_evthread_lock_alloc_fn)(void) = NULL;
    void (*_evthread_lock_free_fn)(void *) = NULL;
    
    void
    evthread_set_locking_callback(void (*locking_fn)(int mode, void *lock))
    {
    #ifdef _EVENT_DISABLE_THREAD_SUPPORT
    	event_errx(1, "%s: not compiled with thread support", __func__);
    #else
    	_evthread_locking_fn = locking_fn;
    #endif
    }
    
    #if defined(_EVENT_HAVE_EVENTFD) && defined(_EVENT_HAVE_SYS_EVENTFD_H)
    static void
    evthread_notify_drain_eventfd(int fd, short what, void *arg)
    {
    	ev_uint64_t msg;
    
    	read(fd, (void*) &msg, sizeof(msg));
    }
    #endif
    
    static void
    evthread_notify_drain_default(evutil_socket_t fd, short what, void *arg)
    {
    	unsigned char buf[128];
    #ifdef WIN32
    	while (recv(fd, (char*)buf, sizeof(buf), 0) > 0)
    		;
    #else
    	while (read(fd, (char*)buf, sizeof(buf)) > 0)
    		;
    #endif
    }
    
    void
    evthread_set_id_callback(unsigned long (*id_fn)(void))
    {
    #ifdef _EVENT_DISABLE_THREAD_SUPPORT
    	event_errx(1, "%s: not compiled with thread support", __func__);
    #else
    	_evthread_id_fn = id_fn;
    #endif
    }
    
    int
    evthread_make_base_notifiable(struct event_base *base)
    {
    	void (*cb)(evutil_socket_t, short, void *) = evthread_notify_drain_default;
    	int (*notify)(struct event_base *) = evthread_notify_base_default;
    
    	if (!base)
    		return -1;
    
    	if (base->th_notify_fd[0] >= 0)
    		return 0;
    
    #if defined(_EVENT_HAVE_EVENTFD) && defined(_EVENT_HAVE_SYS_EVENTFD_H)
    	base->th_notify_fd[0] = eventfd(0, 0);
    	if (base->th_notify_fd[0] >= 0) {
    		notify = evthread_notify_base_eventfd;
    		cb = evthread_notify_drain_eventfd;
    	} else
    #endif
    #if defined(_EVENT_HAVE_PIPE)
    	{
    		if ((base->evsel->features & EV_FEATURE_FDS)) {
    			if (pipe(base->th_notify_fd) < 0)
    				event_warn("%s: pipe", __func__);
    		}
    	}
    	if (base->th_notify_fd[0] < 0)
    #endif
    
    #ifdef WIN32
    #define LOCAL_SOCKETPAIR_AF AF_INET
    #else
    #define LOCAL_SOCKETPAIR_AF AF_UNIX
    #endif
    	{
    		if (evutil_socketpair(LOCAL_SOCKETPAIR_AF, SOCK_STREAM, 0,
    			base->th_notify_fd) == -1) {
    			event_sock_warn(-1, "%s: socketpair", __func__);
    			return (-1);
    		}
    	}
    
    	evutil_make_socket_nonblocking(base->th_notify_fd[0]);
    
    	base->th_notify_fn = notify;
    
    	// This can't be right, can it?  We want writes to this socket to
    	// just succeed.
    	// evutil_make_socket_nonblocking(base->th_notify_fd[1]);
    
    	/* prepare an event that we can use for wakeup */
    	event_assign(&base->th_notify, base, base->th_notify_fd[0],
    				 EV_READ|EV_PERSIST, cb, base);
    
    	/* we need to mark this as internal event */
    	base->th_notify.ev_flags |= EVLIST_INTERNAL;
    
    	event_add(&base->th_notify, NULL);
    
    	return 0;
    }
    
    void
    evthread_set_lock_create_callbacks(void *(*alloc_fn)(void),
        void (*free_fn)(void *))
    {
    #ifdef _EVENT_DISABLE_THREAD_SUPPORT
    	event_errx(1, "%s: not compiled with thread support", __func__);
    #else
    	_evthread_lock_alloc_fn = alloc_fn;
    	_evthread_lock_free_fn = free_fn;
    #endif
    }
    
    void
    event_base_dump_events(struct event_base *base, FILE *output)
    {
    	struct event *e;
    	int i;
    	fprintf(output, "Inserted events:\n");
    	TAILQ_FOREACH(e, &base->eventqueue, ev_next) {
    		fprintf(output, "  %p [fd %ld]%s%s%s%s%s\n",
    				(void*)e, (long)e->ev_fd,
    				(e->ev_events&EV_READ)?" Read":"",
    				(e->ev_events&EV_WRITE)?" Write":"",
    				(e->ev_events&EV_SIGNAL)?" Signal":"",
    				(e->ev_events&EV_TIMEOUT)?" Timeout":"",
    				(e->ev_events&EV_PERSIST)?" Persist":"");
    
    	}
    	for (i = 0; i < base->nactivequeues; ++i) {
    		if (TAILQ_EMPTY(base->activequeues[i]))
    			continue;
    		fprintf(output, "Active events [priority %d]:\n", i);
    		TAILQ_FOREACH(e, &base->eventqueue, ev_next) {
    			fprintf(output, "  %p [fd %ld]%s%s%s%s\n",
    					(void*)e, (long)e->ev_fd,
    					(e->ev_res&EV_READ)?" Read active":"",
    					(e->ev_res&EV_WRITE)?" Write active":"",
    					(e->ev_res&EV_SIGNAL)?" Signal active":"",
    					(e->ev_res&EV_TIMEOUT)?" Timeout active":"");
    		}
    	}
    }