server/server.c

/*
 * Copyright 2015-2016 Rivoreo
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 2 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 */

#define DEFAULT_PORT 3446

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdint.h>

int main(int argc, char **argv) {
	int port = DEFAULT_PORT;
	int fd = socket(AF_INET, SOCK_STREAM, 0);
	if(fd == -1) {
		perror("socket");
		return 1;
	}
	struct sockaddr_in listen_addr = { .sin_family = AF_INET };
	//memset(&listen_addr, 0, sizeof listen_addr);
	listen_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	listen_addr.sin_port = htons(port);

	while(bind(fd, (struct sockaddr *)&listen_addr, sizeof listen_addr) < 0) {
		if(errno == EAGAIN || errno == EINTR) continue;
		perror("bind");
		return 1;
	}

	if(listen(fd, 64) < 0) {
		perror("listen");
		return 1;
	}

	fd_set fdset;
	FD_ZERO(&fdset);
	FD_SET(fd, &fdset);
	int maxfd = fd;

	int client_fds[FD_SETSIZE];
	int i;
	for(i=0; i<FD_SETSIZE; i++) client_fds[i] = -1;

	while(1) {
		fd_set rfdset = fdset;
		int n = select(maxfd + 1, &rfdset, NULL, NULL, NULL);
		if(n < 0) {
			if(errno == EINTR) continue;
			perror("select");
			return 1;
		}
		if(FD_ISSET(fd, &rfdset)) {
			struct sockaddr_in client_addr;
			socklen_t addr_len = sizeof client_addr;
			int cfd;
			do {
				cfd = accept(fd, (struct sockaddr *)&client_addr, &addr_len);
			} while(cfd == -1 && errno == EINTR);
			if(cfd == -1) {
				perror("accept");
				//if(errno == EMFILE) continue;
				//return 1;
				//continue;
				if(errno == EMFILE && n < 2) sleep(1);
			} else {
				fprintf(stderr, "connection from %s port %d fd %d\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), cfd);
/*
				for(i = 0; client_fds[i] != -1; i++) {
				}
*/
				i = 0;
				while(1) {
					if(i >= FD_SETSIZE) {
						fprintf(stderr, "warning: cannot add fd %d to set, too many clients\n", cfd);
						close(cfd);
						break;
					}
					if(client_fds[i] == -1) {
						client_fds[i] = cfd;
						FD_SET(cfd, &fdset);
						if(cfd > maxfd) maxfd = cfd;
						fprintf(stderr, "client %d fd %d\n", i, cfd);
						break;
					}
					i++;
				}
			}
			n--;
		}
		for(i=0; n && i<FD_SETSIZE; i++) {
			int cfd = client_fds[i];
			if(cfd == -1) continue;
			if(FD_ISSET(cfd, &rfdset)) {
				char buffer[1024];
				n--;
				int s = read(cfd, buffer, sizeof buffer);
				if(s < 0) {
					perror("read");
					continue;
				}
				if(s) {
					buffer[s] = 0;
					fprintf(stderr, "got %d bytes from client %d fd %d\nstring: \"%s\"\n",
						s, i, cfd, buffer);
				} else {
					fprintf(stderr, "client %d fd %d closed\n", i, cfd);
					close(cfd);
					FD_CLR(cfd, &fdset);
					client_fds[i] = -1;
				}
			}
		}
	}
}