add epoll

src/server.c

@@ -4,13 +4,8 @@
 int start_server(const char *hostname, const char *service) {
 	struct addrinfo hints;
 	struct addrinfo *res;
-	struct sockaddr_storage their_sa; // incoming clients
-	socklen_t theirsa_size = sizeof their_sa;
 
-	memset(&hints, 0, sizeof hints);
-	hints.ai_family = AF_UNSPEC;	 // IPv4 or IPv6
-	hints.ai_socktype = SOCK_STREAM; // TCP
-	hints.ai_flags = AI_PASSIVE;	 // fill in IP for me
+	setup_hints(&hints, sizeof hints, hostname);
 
 	int status = getaddrinfo(hostname, service, &hints, &res);
 	if (status != 0) {
@@ -20,7 +15,6 @@ int start_server(const char *hostname, const char *service) {
 		exit(EXIT_FAILURE);
 	}
 
-	// socket file descriptor
 	int sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 
 	status = bind(sockfd, res->ai_addr, res->ai_addrlen);
@@ -37,13 +31,103 @@ int start_server(const char *hostname, const char *service) {
 		exit(EXIT_FAILURE);
 	}
 
-	char *msg = "Hello there!";
-	int msg_len = strlen(msg);
-	int newfd = accept(sockfd, (struct sockaddr *)&their_sa, &theirsa_size);
-	int bytes_sent = send(newfd, msg, msg_len, 0);
-	fprintf(stdout, BLUE "[server] Sent %d bytes\n" RESET, bytes_sent);
+	handle_clients(sockfd);
 
 	freeaddrinfo(res);
+	close(sockfd);
 
 	return 0;
 }
+
+void setup_hints(struct addrinfo *hints, size_t len, const char *hostname) {
+	memset(hints, 0, len);
+	hints->ai_family = AF_UNSPEC;	  // IPv4 or IPv6
+	hints->ai_socktype = SOCK_STREAM; // TCP
+	if (hostname == NULL) {
+		hints->ai_flags = AI_PASSIVE; // fill in IP for me
+	}
+}
+
+void handle_clients(int sockfd) {
+	struct sockaddr_storage their_sa;
+	socklen_t theirsa_size = sizeof their_sa;
+
+	int epfd = epoll_create1(0);
+	setnonblocking(sockfd);
+	epoll_ctl_add(epfd, sockfd, EPOLLIN | EPOLLET);
+
+	struct epoll_event *revents =
+	    malloc(EPOLL_MAXEVENTS * sizeof(struct epoll_event));
+	int nfds;
+
+	char *msg = "Hello there!";
+	size_t msg_len = strlen(msg);
+
+	for (;;) {
+		nfds =
+		    epoll_wait(epfd, revents, EPOLL_MAXEVENTS, EPOLL_TIMEOUT);
+
+		for (int i = 0; i < nfds; ++i) {
+			if (revents[i].data.fd == sockfd) {
+				int client_fd =
+				    accept(sockfd, (struct sockaddr *)&their_sa,
+					   &theirsa_size);
+
+				if (client_fd == -1) {
+					if (errno != EWOULDBLOCK) {
+						fprintf(stderr,
+							RED BOLD "[server] "
+								 "accept(): "
+								 "%s\n" RESET,
+							strerror(errno));
+					}
+					continue;
+				}
+
+				setnonblocking(client_fd);
+
+				struct sockaddr_in *client =
+				    (struct sockaddr_in *)&their_sa;
+				char client_ip[INET_ADDRSTRLEN];
+				inet_ntop(AF_INET, &client->sin_addr, client_ip,
+					  INET_ADDRSTRLEN);
+				fprintf(stdout,
+					BLUE "[server] Incoming "
+					     "client, ip: %s\n" RESET,
+					client_ip);
+
+				int bytes_sent =
+				    send(client_fd, msg, msg_len, 0);
+				fprintf(stdout,
+					BLUE "[server] Sent %d bytes\n" RESET,
+					bytes_sent);
+				close(client_fd);
+			}
+		}
+	}
+}
+
+void epoll_ctl_add(int epfd, int sockfd, uint32_t events) {
+	struct epoll_event event;
+	event.events = events;
+	event.data.fd = sockfd;
+	int status = epoll_ctl(epfd, EPOLL_CTL_ADD, sockfd, &event);
+	if (status != 0) {
+		fprintf(stderr, RED BOLD "[server] epoll_ctl(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+}
+
+void setnonblocking(int sockfd) {
+	int status = fcntl(sockfd, F_SETFL, O_NONBLOCK);
+	if (status == -1) {
+		fprintf(stderr, RED BOLD "[server] fcntl(): %s\n" RESET,
+			gai_strerror(status));
+		exit(EXIT_FAILURE);
+	}
+}
+
+void handle_new_client(int sockfd) {
+	// handle here new clients
+}