pollserver.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>

#include <poll.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

void errpro(int condition, const char *errmsg) {
	if (condition) {
		perror(errmsg);
		exit(EXIT_FAILURE);
	}
}

#define PORT	8888U
#define BACKLOG	16U
#define BUFLEN	64U
#define MAXCON	128U

int main() {
	char buf[BUFLEN+1];
	struct sockaddr_in server_addr, client_addr;
	int listen_fd = socket(AF_INET, SOCK_STREAM, 0);
	errpro(-1 == listen_fd, "socket");
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	errpro(-1 == bind(listen_fd, (struct sockaddr *)&server_addr,
				sizeof(server_addr)), "bind");
	errpro(-1 == listen(listen_fd, BACKLOG), "listen");
	struct pollfd fds[MAXCON];
	fds[0].fd = listen_fd;
	fds[0].events = POLLIN;
	int nfds = 1;
	int i;
	for (i = 1; i < MAXCON; ++i) {
		fds[i].fd = -1;
	}
	int concnt = 0; // current connections count
	static int loop = 0;
	for (;;) {
		printf("loop %d\n", ++loop);
		int ret = poll(fds, nfds, 10000);
		errpro(-1 == ret, "poll");
		if (0 == ret) {
			printf("timeout\n");
			break;
		}
		if (fds[0].revents & POLLIN) {
			int sockfd = accept(listen_fd, NULL, NULL);
			errpro(-1 == sockfd, "accept");
			++concnt;
			for (i = 0; i < MAXCON; ++i) {
				if (fds[i].fd < 0) {
					fds[i].fd = sockfd;
					fds[i].events = POLLIN;
					printf("accept fds[%d] = %d\n", i, sockfd);
					break;
				}
			}
			errpro(MAXCON == i, "too many connections");
			if (i+1 > nfds) {
				nfds = i+1;
			}
		}

		// read data
		for (i = 1; i < nfds; ++i) {
			if (fds[i].fd < 0) {
				printf("skipped\n");
			} else if (fds[i].revents & POLLIN) {
				int ret = recv(fds[i].fd, buf, BUFLEN, 0);
				errpro(-1 == ret, "recv");
				if (0 == ret) {
					printf("close fds[%d]\n", i);
					close(fds[i].fd);
					fds[i].fd = -1;
				}
				buf[ret] = '\0';
				printf("message from %d:\n%s", i, buf);
				while (BUFLEN == ret) {
					ret = recv(fds[i].fd, buf, BUFLEN, 0);
					errpro(-1 == ret, "recv");
				}
			} else if (fds[i].revents & POLLERR) {
				printf("fds[%d] error\n", i);
				errpro(EXIT_FAILURE, "POLLERR");
			}
		} // end of read data
	}

	return 0;
}