alternative for libevent. Select() only, only the features needed.

git-svn-id: file:///svn/unbound/trunk@121 be551aaa-1e26-0410-a405-d3ace91eadb9

configure.ac

@@ -354,7 +354,7 @@ AC_ARG_WITH(libevent, AC_HELP_STRING([--with-libevent=pathname],
         ],[
             withval="yes"
         ])
-    if test x_$withval != x_no; then
+if test x_$withval != x_no; then
         AC_MSG_CHECKING(for libevent)
         if test x_$withval = x_ -o x_$withval = x_yes; then
             withval="/usr/local /usr/lib /usr/pkg /usr/sfw /usr";
@@ -382,10 +382,12 @@ AC_ARG_WITH(libevent, AC_HELP_STRING([--with-libevent=pathname],
 	    RUNTIME_PATH="$RUNTIME_PATH -R$thedir/lib"
         fi
 	AC_SUBST(RUNTIME_PATH)
-    fi
-AC_SEARCH_LIBS(event_set, [event])
-AC_CHECK_HEADERS([event.h],,, [AC_INCLUDES_DEFAULT])
-AC_CHECK_FUNCS([event_base_free]) # only in libevent 1.2 and later
+	AC_SEARCH_LIBS(event_set, [event])
+	AC_CHECK_HEADERS([event.h],,, [AC_INCLUDES_DEFAULT])
+	AC_CHECK_FUNCS([event_base_free]) # only in libevent 1.2 and later
+else
+	AC_DEFINE(USE_MINI_EVENT, 1, [Define if you want to use internal select based events])
+fi
 
 # check to see if libraries are needed for these functions.
 AC_CHECK_LIB(socket, socket)

doc/Changelog

@@ -3,6 +3,9 @@
 	- removed check decls, we can compile without them.
 	- makefile supports LIBOBJ replacements.
 	- docs checks ignore compat code.
+	- added util/mini-event.c and .h, a select based alternative used with
+	  ./configure --with-libevent=no
+	  It is limited to 1024 file descriptors, and has less features.
 
 15 February 2007: Wouter
 	- port to FreeBSD 4.11 Dec Alpha. Also works on Solaris 10 sparc64,

util/mini_event.c

@@ -0,0 +1,318 @@
+/*
+ * mini_event.c - implementation of part of libevent api, portably.
+ *
+ * Copyright (c) 2007, 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 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.
+ * 
+ */
+
+/**
+ * \file
+ * fake libevent implementation. Less broad in functionality, and only
+ * supports select(2).
+ */
+
+#include "config.h"
+
+#ifdef USE_MINI_EVENT
+#include <signal.h>
+#include "util/mini_event.h"
+
+/** compare events in tree, based on timevalue, ptr for uniqueness */
+static int 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;
+}
+
+/** create event base */
+void *event_init(void)
+{
+	struct event_base* base = (struct event_base*)malloc(
+		sizeof(struct event_base));
+	if(!base)
+		return NULL;
+	memset(base, 0, sizeof(*base));
+	base->times = rbtree_create(ev_cmp);
+	if(!base->times) {
+		event_base_free(base);
+		return NULL;
+	}
+	base->fds = (struct event**)calloc(MAX_FDS, sizeof(struct event*));
+	if(!base->fds) {
+		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;
+	}
+#ifndef S_SPLINT_S
+	FD_ZERO(&base->reads);
+	FD_ZERO(&base->writes);
+#endif
+	return base;
+}
+
+/** get version */
+const char *event_get_version(void)
+{
+	return "mini-event-"PACKAGE_VERSION;
+}
+
+/** get polling method, select */
+const char *event_get_method(void)
+{
+	return "select";
+}
+
+/** call timeouts handlers, and return how long to wait for next one or -1 */
+static void handle_timeouts(struct event_base* base, time_t now, time_t *wait)
+{
+	struct event* p, *np;
+	*wait = (time_t)-1;
+
+	p = (struct event*)rbtree_first(base->times);
+	while((rbnode_t*)p!=RBTREE_NULL) {
+		/* store next to make deletion possible */
+		np = (struct event*)rbtree_next((rbnode_t*)p);
+		if(!p || p->ev_timeout.tv_sec > now ||
+		(p->ev_timeout.tv_sec==now && p->ev_timeout.tv_usec>0)) {
+			/* there is a next larger timeout. wait for it */
+			*wait = p->ev_timeout.tv_sec - now;
+			if(p->ev_timeout.tv_usec > 0)
+				*wait+=1; /* wait a bit longer */
+			return;
+		}
+		/* event times out, remove it */
+		(void)rbtree_delete(base->times, p);
+		p->ev_events &= ~EV_TIMEOUT;
+		(*p->ev_callback)(p->ev_fd, EV_TIMEOUT, p->ev_arg);
+		/* next is a valid pointer and next larger element */
+		p = np;
+	}
+}
+
+/** call select and callbacks for that */
+static int handle_select(struct event_base* base, time_t wait)
+{
+	struct timeval tv;
+	fd_set r, w;
+	int ret, i;
+
+	tv.tv_sec = wait;
+	tv.tv_usec = 0;
+	memmove(&r, &base->reads, sizeof(fd_set));
+	memmove(&w, &base->writes, sizeof(fd_set));
+
+	if((ret = select(base->maxfd+1, &r, &w, NULL, 
+		(wait==(time_t)-1)?NULL:&tv)) == -1) {
+		return -1;
+	}
+	
+	for(i=0; i<base->maxfd+1; i++) {
+		short bits = 0;
+		if(!base->fds[i]) {
+			continue;
+		}
+		if(FD_ISSET(i, &r)) {
+			bits |= EV_READ;
+			ret--;
+		}
+		if(FD_ISSET(i, &w)) {
+			bits |= EV_WRITE;
+			ret--;
+		}
+		bits &= base->fds[i]->ev_events;
+		if(bits) {
+			(*base->fds[i]->ev_callback)(base->fds[i]->ev_fd, 
+				bits, base->fds[i]->ev_arg);
+			if(ret==0)
+				break;
+		}
+	}
+	return 0;
+}
+
+/** run select in a loop */
+int event_base_dispatch(struct event_base* base)
+{
+	while(!base->need_to_exit)
+	{
+		time_t now = time(NULL), wait;
+		/* see if timeouts need handling */
+		handle_timeouts(base, now, &wait);
+		/* do select */
+		if(handle_select(base, wait) < 0) {
+			if(base->need_to_exit)
+				return 0;
+			return -1;
+		}
+	}
+	return 0;
+}
+
+/** exit that loop */
+int event_base_loopexit(struct event_base* base, 
+	struct timeval* ATTR_UNUSED(tv))
+{
+	base->need_to_exit = 1;
+	return 0;
+}
+
+/** free event base, free events yourself */
+void event_base_free(struct event_base* base)
+{
+	if(base->times)
+		free(base->times);
+	if(base->fds)
+		free(base->fds);
+	if(base->signals)
+		free(base->signals);
+	free(base);
+}
+
+/** set content of event */
+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;
+	ev->ev_arg = arg;
+	ev->added = 0;
+}
+
+/** add event to a base */
+int event_base_set(struct event_base* base, struct event* ev)
+{
+	ev->ev_base = base;
+	ev->added = 0;
+	return 0;
+}
+
+/** add event to make it active, you may not change it with event_set anymore */
+int event_add(struct event* ev, struct timeval* tv)
+{
+	if(ev->added)
+		event_del(ev);
+	if(ev->ev_fd != -1 && ev->ev_fd >= MAX_FDS)
+		return -1;
+	if( (ev->ev_events&(EV_READ|EV_WRITE)) && ev->ev_fd != -1) {
+		ev->ev_base->fds[ev->ev_fd] = ev;
+		if(ev->ev_events&EV_READ)
+			FD_SET(ev->ev_fd, &ev->ev_base->reads);
+		if(ev->ev_events&EV_WRITE)
+			FD_SET(ev->ev_fd, &ev->ev_base->writes);
+		if(ev->ev_fd > ev->ev_base->maxfd)
+			ev->ev_base->maxfd = ev->ev_fd;
+	}
+	if(tv && ev->ev_events&EV_TIMEOUT) {
+#ifndef S_SPLINT_S
+		ev->ev_timeout.tv_sec = tv->tv_sec + time(NULL);
+		ev->ev_timeout.tv_usec = tv->tv_usec;
+#endif
+		(void)rbtree_insert(ev->ev_base->times, &ev->node);
+	}
+	ev->added = 1;
+	return 0;
+}
+
+/** remove event, you may change it again */
+int event_del(struct event* ev)
+{
+	if(ev->ev_fd != -1 && ev->ev_fd >= MAX_FDS)
+		return -1;
+	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) {
+		ev->ev_base->fds[ev->ev_fd] = NULL;
+		FD_CLR(ev->ev_fd, &ev->ev_base->reads);
+		FD_CLR(ev->ev_fd, &ev->ev_base->writes);
+	}
+	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;
+	(*ev->ev_callback)(sig, EV_SIGNAL, ev->ev_arg);
+}
+
+/** install signal handler */
+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;
+}
+
+/** remove signal handler */
+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;
+}
+
+#endif /* USE_MINI_EVENT */

util/mini_event.h

@@ -0,0 +1,146 @@
+/*
+ * mini-event.h - micro implementation of libevent api, using select() only.
+ *
+ * Copyright (c) 2007, 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 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.
+ */
+
+/**
+ * \file
+ * This file implements part of the event(3) libevent api.
+ * The back end is only select. Max number of fds is limited.
+ */
+
+#ifndef MINI_EVENT_H
+#define MINI_EVENT_H
+
+#ifdef USE_MINI_EVENT
+
+#ifndef HAVE_EVENT_BASE_FREE
+#define HAVE_EVENT_BASE_FREE
+#endif 
+
+/** event timeout */
+#define EV_TIMEOUT	0x01
+/** event fd readable */
+#define EV_READ		0x02
+/** event fd writable */
+#define EV_WRITE	0x04
+/** event signal */
+#define EV_SIGNAL	0x08
+/** event must persist */
+#define EV_PERSIST	0x10
+
+/* needs our redblack tree */
+#include "rbtree.h"
+
+/** max number of file descriptors to support */
+#define MAX_FDS 1024
+/** max number of signals to support */
+#define MAX_SIG 32
+
+/** event base */
+struct event_base
+{
+	/** sorted by timeout (absolute), ptr */
+	rbtree_t* times;
+	/** array of 0 - maxfd of ptr to event for it */
+	struct event** fds;
+	/** max fd in use */
+	int maxfd;
+	/** fdset for read write */
+	fd_set reads, writes;
+	/** array of 0 - maxsig of ptr to event for it */
+	struct event** signals;
+	/** if we need to exit */
+	int need_to_exit;
+};
+
+/**
+ * Event structure. Has some of the event elements.
+ */
+struct event {
+	/** node in timeout rbtree */
+	rbnode_t node;
+	/** is event already added */
+	int added;
+
+	/** event base it belongs to */
+	struct event_base *ev_base;
+	/** fd to poll or -1 for timeouts */
+	int ev_fd;
+	/** events this event is interested in */
+	short ev_events;
+	/** timeout value */
+	struct timeval ev_timeout;
+
+	/** callback to call: fd, eventbits, userarg */
+	void (*ev_callback)(int, short, void *arg);
+	/** callback user arg */
+	void *ev_arg;
+};
+
+/* function prototypes as they appear in event.h */
+/** create event base */
+void *event_init(void);
+/** get version */
+const char *event_get_version(void);
+/** get polling method, select */
+const char *event_get_method(void);
+/** run select in a loop */
+int event_base_dispatch(struct event_base *);
+/** exit that loop */
+int event_base_loopexit(struct event_base *, struct timeval *);
+/** free event base. Free events yourself */
+void event_base_free(struct event_base *);
+/** set content of event */
+void event_set(struct event *, int, short, void (*)(int, short, void *), void *);
+/** add event to a base */
+int event_base_set(struct event_base *, struct event *);
+/** add event to make it active. You may not change it with event_set anymore */
+int event_add(struct event *, struct timeval *);
+/** remove event. You may change it again */
+int event_del(struct event *);
+
+#define evtimer_add(ev, tv)             event_add(ev, tv)
+#define evtimer_del(ev)                 event_del(ev)
+
+/* uses different implementation. Cannot mix fd/timeouts and signals. */
+/** install signal handler */
+int signal_add(struct event *, struct timeval *);
+/** set signal event contents */
+#define signal_set(ev, x, cb, arg)      \
+        event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg)
+/** remove signal handler */
+int signal_del(struct event *);
+
+#endif /* USE_MINI_EVENT */
+#endif /* MINI_EVENT_H */

util/netevent.c

@@ -49,8 +49,12 @@
 
 /* We define libevent structures here to hide the libevent stuff. */
 
+#ifdef USE_MINI_EVENT
+#include "util/mini_event.h"
+#else
 /* we use libevent */
 #include <event.h>
+#endif
 
 /**
  * The internal event structure for keeping libevent info for the event.
@@ -159,7 +163,8 @@ comm_base_create()
 		free(b);
 		return NULL;
 	}
-	verbose(VERB_ALGO, "libevent uses %s method.", event_get_method());
+	verbose(VERB_ALGO, "libevent %s uses %s method.", 
+		event_get_version(), event_get_method());
 	return b;
 }