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
28 static const char MESSAGE[] = "Hello, World!\n";
29
30 static const int PORT = 9995;
31
32 static void listener_cb(struct evconnlistener *, evutil_socket_t,
33 struct sockaddr *, int socklen, void *);
34 static void conn_writecb(struct bufferevent *, void *);
35 static void conn_eventcb(struct bufferevent *, short, void *);
36 static void signal_cb(evutil_socket_t, short, void *);
37
38 int
main(int argc,char ** argv)39 main(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
87 static void
listener_cb(struct evconnlistener * listener,evutil_socket_t fd,struct sockaddr * sa,int socklen,void * user_data)88 listener_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
107 static void
conn_writecb(struct bufferevent * bev,void * user_data)108 conn_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
117 static void
conn_eventcb(struct bufferevent * bev,short events,void * user_data)118 conn_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
131 static void
signal_cb(evutil_socket_t sig,short events,void * user_data)132 signal_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