SimpleEventBuilder/event_builder.cxx

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#include <arpa/inet.h>
#include <csignal>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <errno.h>
#include <queue>
#include <vector>
int makeSocket() {
int sockfd;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}
return sockfd;
}
void bindSocketPort(int server_fd, int port) {
struct sockaddr_in localAddr;
localAddr.sin_family = AF_INET;
localAddr.sin_addr.s_addr = INADDR_ANY;
localAddr.sin_port = htons(port);
if (bind(server_fd, (struct sockaddr *)&localAddr, sizeof(localAddr)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
printf("FD %d bound to port %d\n", server_fd, port);
}
void startListening(int server_fd) {
if (listen(server_fd, 3) < 0) {
perror("listen");
exit(EXIT_FAILURE);
}
printf("FD %d listening to new connections\n", server_fd);
}
int acceptConnection(int server_fd) {
int client_fd;
struct sockaddr_in remoteAddr;
size_t addrlen = sizeof(remoteAddr);
if ((client_fd = accept(server_fd, (struct sockaddr *)&remoteAddr, (socklen_t *)&addrlen)) < 0) {
perror("accept");
exit(EXIT_FAILURE);
}
printf("Connection from host %s, port %d, FD %d\n", inet_ntoa(remoteAddr.sin_addr), ntohs(remoteAddr.sin_port), client_fd);
return client_fd;
}
void term_handler(int signal) {
printf("Terminated, received SIGNAL %d", signal);
exit(EXIT_SUCCESS);
}
/*
int main(int argc, char const *argv[]) {
signal(SIGTERM, term_handler);
if (argc != 2) {
printf("Usage: %s portNumber \n", argv[0]);
exit(EXIT_FAILURE);
}
int port = atoi(argv[1]);
printf("Start socket port %d\n", port);
int server_fd = makeSocket();
bindSocketPort(server_fd, port);
startListening(server_fd);
int client_fd = acceptConnection(server_fd);
while (true) {
uint32_t word;
ssize_t bytes = read(client_fd, &word, 4);
if (bytes != 4) {
perror("Receive failed");
exit(EXIT_FAILURE);
}
printf("[RICEVUTO]\t0x%x\n", word);
}
return 0;
}*/
#define TRUE 1
#define FALSE 0
int main(int argc, char const *argv[]) {
signal(SIGTERM, term_handler);
if (argc != 2) {
printf("Usage: %s portNumber \n", argv[0]);
exit(EXIT_FAILURE);
}
int port = atoi(argv[1]);
printf("Start socket port %d\n", port);
int opt = TRUE;
int master_socket , addrlen , new_socket , client_socket[30] ,
max_clients = 30 , activity, i , valread , sd;
int max_sd;
//set of socket descriptors
fd_set readfds;
//initialise all client_socket[] to 0 so not checked
for (i = 0; i < max_clients; i++)
{
client_socket[i] = 0;
}
master_socket = makeSocket();
//set master socket to allow multiple connections ,
//this is just a good habit, it will work without this
if( setsockopt(master_socket, SOL_SOCKET, SO_REUSEADDR, (char *)&opt,
sizeof(opt)) < 0 )
{
perror("setsockopt");
exit(EXIT_FAILURE);
}
bindSocketPort(master_socket, port);
startListening(master_socket);
while (true) {
//clear the socket set
FD_ZERO(&readfds);
//add master socket to set
FD_SET(master_socket, &readfds);
max_sd = master_socket;
//add child sockets to set
for ( i = 0 ; i < max_clients ; i++)
{
//socket descriptor
sd = client_socket[i];
//if valid socket descriptor then add to read list
if(sd > 0)
FD_SET( sd , &readfds);
//highest file descriptor number, need it for the select function
if(sd > max_sd)
max_sd = sd;
}
//wait for an activity on one of the sockets , timeout is NULL ,
//so wait indefinitely
activity = select( max_sd + 1 , &readfds , NULL , NULL , NULL);
if ((activity < 0) && (errno!=EINTR))
{
printf("select error");
}
//If something happened on the master socket ,
//then its an incoming connection
if (FD_ISSET(master_socket, &readfds))
{
new_socket = acceptConnection(master_socket);
//add new socket to array of sockets
for (i = 0; i < max_clients; i++)
{
//if position is empty
if( client_socket[i] == 0 )
{
client_socket[i] = new_socket;
printf("Adding to list of sockets as %d\n" , i);
break;
}
}
}
//else its some IO operation on some other socket
for (i = 0; i < max_clients; i++)
{
sd = client_socket[i];
if (FD_ISSET( sd , &readfds))
{
//Check if it was for closing , and also read the
//incoming message
uint32_t word;
if ((valread = recv( sd , &word, 4, 0)) == 0)
{
struct sockaddr_in address;
int addrlen;
//Somebody disconnected , get his details and print
getpeername(sd , (struct sockaddr*)&address , \
(socklen_t*)&addrlen);
printf("Host disconnected , ip %s , port %d \n" ,
inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
printf("Disconnected fd %d", sd);
//Close the socket and mark as 0 in list for reuse
close( sd );
client_socket[i] = 0;
}
//Echo back the message that came in
else
{
printf("[RICEVUTO]\t0x%x FROM %d\n", word, sd);
}
}
}
}
/*
int client_fd = acceptConnection(server_fd);
while (true) {
uint32_t word;
ssize_t bytes = read(client_fd, &word, 4);
if (bytes != 4) {
perror("Receive failed");
exit(EXIT_FAILURE);
}
printf("[RICEVUTO]\t0x%x\n", word);
}*/
return 0;
}