1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/c++/domain-socket-bridge/domain-socket-bridge.cpp Sun Nov 20 20:40:30 2016 +0100
1.3 @@ -0,0 +1,224 @@
1.4 +#include <string.h>
1.5 +#include <errno.h>
1.6 +#include <stdio.h>
1.7 +#include <signal.h>
1.8 +#include <stdlib.h>
1.9 +#include <string>
1.10 +#include <regex>
1.11 +
1.12 +#include <event2/bufferevent.h>
1.13 +#include <event2/buffer.h>
1.14 +#include <event2/listener.h>
1.15 +#include <event2/util.h>
1.16 +#include <event2/event.h>
1.17 +#include <sys/socket.h>
1.18 +#include <sys/un.h>
1.19 +#include <unistd.h>
1.20 +
1.21 +using namespace std;
1.22 +
1.23 +static const char MESSAGE[] = "Hello, World!\n";
1.24 +
1.25 +static const char PATH[] = "./roura";
1.26 +
1.27 +static const string COMMAND_EXIT("exit\n");
1.28 +
1.29 +static void listener_cb(evutil_socket_t, short, void *);
1.30 +static void conn_read_cb(struct bufferevent *, void *);
1.31 +static void conn_write_cb(struct bufferevent *, void *);
1.32 +static void conn_event_cb(struct bufferevent *, short, void *);
1.33 +static void signal_cb(evutil_socket_t, short, void *);
1.34 +static void print_socket_info(int, int);
1.35 +
1.36 +int main(int argc, char **argv) {
1.37 + printf("%4s %8s\n", "*", "STARTED");
1.38 + struct event_base *base;
1.39 + evutil_socket_t listener;
1.40 + struct event *listener_event;
1.41 + struct event *signal_event;
1.42 +
1.43 + struct sockaddr_un sun;
1.44 +
1.45 + setvbuf(stdout, NULL, _IONBF, 0);
1.46 +
1.47 + base = event_base_new();
1.48 + if (!base) {
1.49 + printf("%4s %8s %s\n", "*", "ERROR", "unable to initialize libevent");
1.50 + return 1;
1.51 + }
1.52 +
1.53 + memset(&sun, 0, sizeof (sun));
1.54 + sun.sun_family = AF_UNIX;
1.55 + strcpy(sun.sun_path, PATH);
1.56 +
1.57 + listener = socket(AF_UNIX, SOCK_STREAM, 0);
1.58 + evutil_make_socket_nonblocking(listener);
1.59 +
1.60 + if (bind(listener, (struct sockaddr*) &sun, sizeof (sun)) < 0) {
1.61 + printf("%4s %8s %s: %s\n", "*", "ERROR", "unable to create domain socket:", PATH);
1.62 + return 1;
1.63 + }
1.64 +
1.65 + if (listen(listener, 16) < 0) {
1.66 + printf("%4s %8s %s\n", "*", "ERROR", "unable to listen");
1.67 + return 1;
1.68 + }
1.69 +
1.70 + // identifikátor serverového soketu (v současnosti číslo FD)
1.71 + printf("%4s %8s listening at: sun_path = %s → socketId = %d\n", "*", "SOCKET", sun.sun_path, listener);
1.72 +
1.73 + listener_event = event_new(base, listener, EV_READ | EV_PERSIST, listener_cb, (void*) base);
1.74 +
1.75 + if (!listener_event) {
1.76 + printf("%4s %8s %s\n", "*", "ERROR", "unable to do event_new()");
1.77 + return 1;
1.78 + }
1.79 +
1.80 + event_add(listener_event, NULL);
1.81 +
1.82 + signal_event = evsignal_new(base, SIGINT, signal_cb, (void *) base);
1.83 +
1.84 + if (!signal_event || event_add(signal_event, NULL) < 0) {
1.85 + printf("%4s %8s %s\n", "*", "ERROR", "unable to create/add a signal event");
1.86 + return 1;
1.87 + }
1.88 +
1.89 + event_base_dispatch(base);
1.90 +
1.91 + event_free(listener_event);
1.92 + event_free(signal_event);
1.93 + event_base_free(base);
1.94 +
1.95 + // smažeme soket na disku / soubor -- jinak by program příště spadl na bind()
1.96 + // TODO: co když soket někdo přesune a místo něj dá jiný soubor?
1.97 + unlink(PATH);
1.98 +
1.99 + printf("%4s %8s\n", "*", "FINISHED");
1.100 + return 0;
1.101 +}
1.102 +
1.103 +static void listener_cb(evutil_socket_t listener, short event, void *user_data) {
1.104 + struct event_base *base = (event_base *) user_data;
1.105 + struct bufferevent *bev;
1.106 +
1.107 + struct sockaddr_storage ss;
1.108 + socklen_t slen = sizeof (ss);
1.109 + int fd = accept(listener, (struct sockaddr*) &ss, &slen);
1.110 +
1.111 + // identifikátor navázaného spojení (v současnosti číslo FD)
1.112 + int * connectionId = (int*) malloc(sizeof (fd));
1.113 + *connectionId = fd;
1.114 +
1.115 + if (fd < 0) {
1.116 + printf("%4d %8s %s\n", *connectionId, "ERROR", "unable to accept()");
1.117 + return;
1.118 + } else if (fd > FD_SETSIZE) {
1.119 + // FD_SETSIZE = 1024 -- Proč? Co když bude spojení víc?
1.120 + printf("%4d %8s fd (%d) > FD_SETSIZE (%d)\n", *connectionId, "ERROR", fd, FD_SETSIZE);
1.121 + close(fd);
1.122 + return;
1.123 + }
1.124 +
1.125 + evutil_make_socket_nonblocking(fd);
1.126 +
1.127 +
1.128 + bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
1.129 + if (!bev) {
1.130 + printf("%4d %8s %s\n", *connectionId, "ERROR", "constructing bufferevent");
1.131 + event_base_loopbreak(base);
1.132 + return;
1.133 + }
1.134 +
1.135 +
1.136 +
1.137 +
1.138 + bufferevent_setcb(bev, conn_read_cb, conn_write_cb, conn_event_cb, (void*) connectionId);
1.139 + bufferevent_enable(bev, EV_READ | EV_WRITE);
1.140 +
1.141 + printf("%4d %8s somebody has connected: socketId = %d → connectionId = %d\n", *connectionId, "CONN", listener, *connectionId);
1.142 + print_socket_info(*connectionId, fd);
1.143 +
1.144 + bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
1.145 +}
1.146 +
1.147 +static void conn_read_cb(struct bufferevent *bev, void *user_data) {
1.148 + int connectionId = *((int*) user_data);
1.149 +
1.150 + /* This callback is invoked when there is data to read on bev. */
1.151 + struct evbuffer *input = bufferevent_get_input(bev);
1.152 + struct evbuffer *output = bufferevent_get_output(bev);
1.153 + struct event_base *base = bufferevent_get_base(bev);
1.154 +
1.155 + size_t len = evbuffer_get_length(input);
1.156 + char *data = (char*) malloc(len);
1.157 + evbuffer_copyout(input, data, len);
1.158 +
1.159 +
1.160 + string dataFormated(data);
1.161 + dataFormated = regex_replace(dataFormated, regex("\\n"), "\\n");
1.162 + printf("%4d %8s '%s'\n", connectionId, "IN", dataFormated.c_str());
1.163 +
1.164 + if (COMMAND_EXIT.compare(data) == 0) {
1.165 + struct timeval delay = {2, 123};
1.166 + printf("%4d %8s client asks us to terminate; finishing in %ld sesonds and %ld microseconds\n", connectionId, "EXIT", delay.tv_sec, delay.tv_usec);
1.167 + event_base_loopexit(base, &delay);
1.168 + }
1.169 +
1.170 + evbuffer_add(output, "echo: ", 6);
1.171 + /* Copy all the data from the input buffer to the output buffer. */
1.172 + evbuffer_add_buffer(output, input);
1.173 + free(data);
1.174 +}
1.175 +
1.176 +static void conn_write_cb(struct bufferevent *bev, void *user_data) {
1.177 + int connectionId = *((int*) user_data);
1.178 +
1.179 + struct evbuffer *output = bufferevent_get_output(bev);
1.180 + if (evbuffer_get_length(output) == 0) {
1.181 + printf("%4d %8s\n", connectionId, "FLUSH");
1.182 + /* nebudeme ukončovat spojení
1.183 + bufferevent_free(bev);
1.184 + */
1.185 + } else {
1.186 + // FIXME: sem to nikdy nepřijde
1.187 + size_t len = evbuffer_get_length(output);
1.188 + char *data = (char*) malloc(len);
1.189 + evbuffer_copyout(output, data, len);
1.190 + printf("%4d %8s '%s'\n", connectionId, "OUT", data);
1.191 + free(data);
1.192 + }
1.193 +}
1.194 +
1.195 +static void conn_event_cb(struct bufferevent *bev, short events, void *user_data) {
1.196 + int connectionId = *((int*) user_data);
1.197 +
1.198 + if (events & BEV_EVENT_EOF) {
1.199 + printf("%4d %8s\n", connectionId, "CLOSE");
1.200 + } else if (events & BEV_EVENT_ERROR) {
1.201 + printf("%4d %8s %s\n", connectionId, "ERROR", strerror(errno));
1.202 + } else {
1.203 + printf("%4d %8s\n", connectionId, "OTHER");
1.204 + // None of the other events can happen here, since we haven't enabled timeouts
1.205 + }
1.206 +
1.207 + bufferevent_free(bev);
1.208 + free(user_data);
1.209 +}
1.210 +
1.211 +static void signal_cb(evutil_socket_t sig, short events, void *user_data) {
1.212 + struct event_base *base = (event_base *) user_data;
1.213 + struct timeval delay = {2, 123};
1.214 +
1.215 + printf("\n%4s %8s got SIGINT (Ctrl+C); finishing in %ld sesonds and %ld microseconds\n", "*", "SIGNAL", delay.tv_sec, delay.tv_usec);
1.216 +
1.217 + event_base_loopexit(base, &delay);
1.218 +}
1.219 +
1.220 +static void print_socket_info(int connectionId, int fd) {
1.221 + struct ucred cr;
1.222 + unsigned int cl = sizeof (cr);
1.223 +
1.224 + if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &cl) == 0) {
1.225 + printf("%4d %8s client identification: pid=%d, uid=%d, gid=%d\n", connectionId, "CONN", cr.pid, cr.uid, cr.gid);
1.226 + }
1.227 +}
1.228 \ No newline at end of file