external/bsd/libevent/dist/sample/hello-world.c

   1 /*      $NetBSD: hello-world.c,v 1.1.1.1 2013/04/11 16:43:31 christos Exp $     */
   2 /*
   3   This exmple program provides a trivial server program that listens for TCP
   4   connections on port 9995.  When they arrive, it writes a short message to
   5   each client connection, and closes each connection once it is flushed.
   6
   7   Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
   8 */
   9
  10
  11 #include <string.h>
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <signal.h>
  15 #ifndef WIN32
  16 #include <netinet/in.h>
  17 # ifdef _XOPEN_SOURCE_EXTENDED
  18 #  include <arpa/inet.h>
  19 # endif
  20 #include <sys/socket.h>
  21 #endif
  22
  23 #include <event2/bufferevent.h>
  24 #include <event2/buffer.h>
  25 #include <event2/listener.h>
  26 #include <event2/util.h>
  27 #include <event2/event.h>
  28
  29 static const char MESSAGE[] = "Hello, World!\n";
  30
  31 static const int PORT = 9995;
  32
  33 static void listener_cb(struct evconnlistener *, evutil_socket_t,
  34     struct sockaddr *, int socklen, void *);
  35 static void conn_writecb(struct bufferevent *, void *);
  36 static void conn_eventcb(struct bufferevent *, short, void *);
  37 static void signal_cb(evutil_socket_t, short, void *);
  38
  39 int
  40 main(int argc, char **argv)
  41 {
  42         struct event_base *base;
  43         struct evconnlistener *listener;
  44         struct event *signal_event;
  45
  46         struct sockaddr_in sin;
  47 #ifdef WIN32
  48         WSADATA wsa_data;
  49         WSAStartup(0x0201, &wsa_data);
  50 #endif
  51
  52         base = event_base_new();
  53         if (!base) {
  54                 fprintf(stderr, "Could not initialize libevent!\n");
  55                 return 1;
  56         }
  57
  58         memset(&sin, 0, sizeof(sin));
  59         sin.sin_family = AF_INET;
  60         sin.sin_port = htons(PORT);
  61
  62         listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
  63             LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
  64             (struct sockaddr*)&sin,
  65             sizeof(sin));
  66
  67         if (!listener) {
  68                 fprintf(stderr, "Could not create a listener!\n");
  69                 return 1;
  70         }
  71
  72         signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
  73
  74         if (!signal_event || event_add(signal_event, NULL)<0) {
  75                 fprintf(stderr, "Could not create/add a signal event!\n");
  76                 return 1;
  77         }
  78
  79         event_base_dispatch(base);
  80
  81         evconnlistener_free(listener);
  82         event_free(signal_event);
  83         event_base_free(base);
  84
  85         printf("done\n");
  86         return 0;
  87 }
  88
  89 static void
  90 listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
  91     struct sockaddr *sa, int socklen, void *user_data)
  92 {
  93         struct event_base *base = user_data;
  94         struct bufferevent *bev;
  95
  96         bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
  97         if (!bev) {
  98                 fprintf(stderr, "Error constructing bufferevent!");
  99                 event_base_loopbreak(base);
 100                 return;
 101         }
 102         bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
 103         bufferevent_enable(bev, EV_WRITE);
 104         bufferevent_disable(bev, EV_READ);
 105
 106         bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
 107 }
 108
 109 static void
 110 conn_writecb(struct bufferevent *bev, void *user_data)
 111 {
 112         struct evbuffer *output = bufferevent_get_output(bev);
 113         if (evbuffer_get_length(output) == 0) {
 114                 printf("flushed answer\n");
 115                 bufferevent_free(bev);
 116         }
 117 }
 118
 119 static void
 120 conn_eventcb(struct bufferevent *bev, short events, void *user_data)
 121 {
 122         if (events & BEV_EVENT_EOF) {
 123                 printf("Connection closed.\n");
 124         } else if (events & BEV_EVENT_ERROR) {
 125                 printf("Got an error on the connection: %s\n",
 126                     strerror(errno));/*XXX win32*/
 127         }
 128         /* None of the other events can happen here, since we haven't enabled
 129          * timeouts */
 130         bufferevent_free(bev);
 131 }
 132
 133 static void
 134 signal_cb(evutil_socket_t sig, short events, void *user_data)
 135 {
 136         struct event_base *base = user_data;
 137         struct timeval delay = { 2, 0 };
 138
 139         printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
 140
 141         event_base_loopexit(base, &delay);
 142 }