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@moccos
Last active May 14, 2018 06:17
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Modified libevent / sample / hello-world.c
/*
This exmple program provides a trivial server program that listens for TCP
connections on port 9995. When they arrive, it writes a short message to
each client connection, and closes each connection once it is flushed.
Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
*/
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#ifndef _WIN32
#include <netinet/in.h>
# ifdef _XOPEN_SOURCE_EXTENDED
# include <arpa/inet.h>
# endif
#include <sys/socket.h>
#endif
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/listener.h>
#include <event2/util.h>
#include <event2/event.h>
#include <algorithm>
static const char MESSAGE[] = "Hello, World!\n";
static const int PORT = 9995;
static void listener_cb(struct evconnlistener *, evutil_socket_t,
struct sockaddr *, int socklen, void *);
static void conn_readcb(struct bufferevent *, void *);
static void conn_writecb(struct bufferevent *, void *);
static void conn_eventcb(struct bufferevent *, short, void *);
static void signal_cb(evutil_socket_t, short, void *);
int
main(int argc, char **argv)
{
struct event_base *base;
struct evconnlistener *listener;
struct event *signal_event;
struct sockaddr_in sin;
#ifdef _WIN32
WSADATA wsa_data;
WSAStartup(0x0201, &wsa_data);
#endif
base = event_base_new();
if (!base) {
fprintf(stderr, "Could not initialize libevent!\n");
return 1;
}
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(PORT);
listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
(struct sockaddr*)&sin,
sizeof(sin));
if (!listener) {
fprintf(stderr, "Could not create a listener!\n");
return 1;
}
signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
if (!signal_event || event_add(signal_event, NULL)<0) {
fprintf(stderr, "Could not create/add a signal event!\n");
return 1;
}
event_base_dispatch(base);
evconnlistener_free(listener);
event_free(signal_event);
event_base_free(base);
printf("done\n");
return 0;
}
static void
listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
struct sockaddr *sa, int socklen, void *user_data)
{
struct event_base *base = (struct event_base*)user_data;
struct bufferevent *bev;
bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
if (!bev) {
fprintf(stderr, "Error constructing bufferevent!");
event_base_loopbreak(base);
return;
}
bufferevent_setcb(bev, conn_readcb, conn_writecb, conn_eventcb, nullptr);
printf("listener_cb\n");
bufferevent_enable(bev, EV_READ);
//bufferevent_enable(bev, EV_WRITE);
//bufferevent_disable(bev, EV_READ);
//bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
}
static void
conn_readcb(struct bufferevent *bev, void *user_data)
{
struct evbuffer *input = bufferevent_get_input(bev);
auto len = evbuffer_get_length(input);
printf("conn_readcb: len %lu\n", len);
char *buf = (char*)malloc(len);
evbuffer_copyout(input, buf, len);
for (auto i = 0; i < std::min((int)len, 4); ++i) {
printf("%02x ", buf[i]);
}
printf("\n");
evbuffer_drain(input, len);
}
static void
conn_writecb(struct bufferevent *bev, void *user_data)
{
printf("conn_writecb\n");
struct evbuffer *output = bufferevent_get_output(bev);
if (evbuffer_get_length(output) == 0) {
printf("flushed answer\n");
bufferevent_free(bev);
}
}
static void
conn_eventcb(struct bufferevent *bev, short events, void *user_data)
{
printf("conn_eventcb\n");
if (events & BEV_EVENT_EOF) {
printf("Connection closed.\n");
} else if (events & BEV_EVENT_ERROR) {
printf("Got an error on the connection: %s\n",
strerror(errno));/*XXX win32*/
}
/* None of the other events can happen here, since we haven't enabled
* timeouts */
bufferevent_free(bev);
}
static void
signal_cb(evutil_socket_t sig, short events, void *user_data)
{
struct event_base *base = (struct event_base*)user_data;
struct timeval delay = { 2, 0 };
printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
event_base_loopexit(base, &delay);
}
% telnet localhost 9995
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
asdf
^T^@
Connection closed by foreign host.
% ./ev_test
listener_cb
conn_readcb: len 6
61 73 64 66
conn_readcb: len 4
14 00 0d 0a
conn_readcb: len 2
0d 0a
^CCaught an interrupt signal; exiting cleanly in two seconds.
done
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