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 = {0};
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	sin.sin_family = AF_INET;
58	sin.sin_port = htons(PORT);
59
60	listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
61	    LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
62	    (struct sockaddr*)&sin,
63	    sizeof(sin));
64
65	if (!listener) {
66		fprintf(stderr, "Could not create a listener!\n");
67		return 1;
68	}
69
70	signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
71
72	if (!signal_event || event_add(signal_event, NULL)<0) {
73		fprintf(stderr, "Could not create/add a signal event!\n");
74		return 1;
75	}
76
77	event_base_dispatch(base);
78
79	evconnlistener_free(listener);
80	event_free(signal_event);
81	event_base_free(base);
82
83	printf("done\n");
84	return 0;
85}
86
87static void
88listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
89    struct sockaddr *sa, int socklen, void *user_data)
90{
91	struct event_base *base = user_data;
92	struct bufferevent *bev;
93
94	bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
95	if (!bev) {
96		fprintf(stderr, "Error constructing bufferevent!");
97		event_base_loopbreak(base);
98		return;
99	}
100	bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
101	bufferevent_enable(bev, EV_WRITE);
102	bufferevent_disable(bev, EV_READ);
103
104	bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
105}
106
107static void
108conn_writecb(struct bufferevent *bev, void *user_data)
109{
110	struct evbuffer *output = bufferevent_get_output(bev);
111	if (evbuffer_get_length(output) == 0) {
112		printf("flushed answer\n");
113		bufferevent_free(bev);
114	}
115}
116
117static void
118conn_eventcb(struct bufferevent *bev, short events, void *user_data)
119{
120	if (events & BEV_EVENT_EOF) {
121		printf("Connection closed.\n");
122	} else if (events & BEV_EVENT_ERROR) {
123		printf("Got an error on the connection: %s\n",
124		    strerror(errno));/*XXX win32*/
125	}
126	/* None of the other events can happen here, since we haven't enabled
127	 * timeouts */
128	bufferevent_free(bev);
129}
130
131static void
132signal_cb(evutil_socket_t sig, short events, void *user_data)
133{
134	struct event_base *base = user_data;
135	struct timeval delay = { 2, 0 };
136
137	printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
138
139	event_base_loopexit(base, &delay);
140}
141