1/*
2  This example program provides a trivial server program that listens for TCP
3  connections on port 9995.  When they arrive, it writes a short message to
4  each client connection, and closes each connection once it is flushed.
5
6  Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
7*/
8
9
10#include <string.h>
11#include <errno.h>
12#include <stdio.h>
13#include <signal.h>
14#ifndef _WIN32
15#include <netinet/in.h>
16# ifdef _XOPEN_SOURCE_EXTENDED
17#  include <arpa/inet.h>
18# endif
19#include <sys/socket.h>
20#endif
21
22#include <event2/bufferevent.h>
23#include <event2/buffer.h>
24#include <event2/listener.h>
25#include <event2/util.h>
26#include <event2/event.h>
27
28static const char MESSAGE[] = "Hello, World!\n";
29
30static const int PORT = 9995;
31
32static void listener_cb(struct evconnlistener *, evutil_socket_t,
33    struct sockaddr *, int socklen, void *);
34static void conn_writecb(struct bufferevent *, void *);
35static void conn_eventcb(struct bufferevent *, short, void *);
36static void signal_cb(evutil_socket_t, short, void *);
37
38int
39main(int argc, char **argv)
40{
41	struct event_base *base;
42	struct evconnlistener *listener;
43	struct event *signal_event;
44
45	struct sockaddr_in sin;
46#ifdef _WIN32
47	WSADATA wsa_data;
48	WSAStartup(0x0201, &wsa_data);
49#endif
50
51	base = event_base_new();
52	if (!base) {
53		fprintf(stderr, "Could not initialize libevent!\n");
54		return 1;
55	}
56
57	memset(&sin, 0, sizeof(sin));
58	sin.sin_family = AF_INET;
59	sin.sin_port = htons(PORT);
60
61	listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
62	    LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
63	    (struct sockaddr*)&sin,
64	    sizeof(sin));
65
66	if (!listener) {
67		fprintf(stderr, "Could not create a listener!\n");
68		return 1;
69	}
70
71	signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
72
73	if (!signal_event || event_add(signal_event, NULL)<0) {
74		fprintf(stderr, "Could not create/add a signal event!\n");
75		return 1;
76	}
77
78	event_base_dispatch(base);
79
80	evconnlistener_free(listener);
81	event_free(signal_event);
82	event_base_free(base);
83
84	printf("done\n");
85	return 0;
86}
87
88static void
89listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
90    struct sockaddr *sa, int socklen, void *user_data)
91{
92	struct event_base *base = user_data;
93	struct bufferevent *bev;
94
95	bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
96	if (!bev) {
97		fprintf(stderr, "Error constructing bufferevent!");
98		event_base_loopbreak(base);
99		return;
100	}
101	bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
102	bufferevent_enable(bev, EV_WRITE);
103	bufferevent_disable(bev, EV_READ);
104
105	bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
106}
107
108static void
109conn_writecb(struct bufferevent *bev, void *user_data)
110{
111	struct evbuffer *output = bufferevent_get_output(bev);
112	if (evbuffer_get_length(output) == 0) {
113		printf("flushed answer\n");
114		bufferevent_free(bev);
115	}
116}
117
118static void
119conn_eventcb(struct bufferevent *bev, short events, void *user_data)
120{
121	if (events & BEV_EVENT_EOF) {
122		printf("Connection closed.\n");
123	} else if (events & BEV_EVENT_ERROR) {
124		printf("Got an error on the connection: %s\n",
125		    strerror(errno));/*XXX win32*/
126	}
127	/* None of the other events can happen here, since we haven't enabled
128	 * timeouts */
129	bufferevent_free(bev);
130}
131
132static void
133signal_cb(evutil_socket_t sig, short events, void *user_data)
134{
135	struct event_base *base = user_data;
136	struct timeval delay = { 2, 0 };
137
138	printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
139
140	event_base_loopexit(base, &delay);
141}
142