网络编程五种IO模型之poll模型

// poll_impl.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"

#include  
#include         /* basic system data types */
#include        /* basic socket definitions */
#include        /* sockaddr_in{} and other Internet defns */
#include         /* inet(3) functions */

#include 
#include 
#include 
#include 


#include  /* poll function */
#include 

#define MAXLINE 10240

#ifndef OPEN_MAX
#define OPEN_MAX 40960
#endif

void handle(struct pollfd* clients, int maxClient, int readyClient);

int  main(int argc, char **argv)
{
	int servPort = 6888;
	int listenq = 1024;
	int listenfd, connfd;
	struct pollfd clients[OPEN_MAX];
	int  maxi;
	socklen_t socklen = sizeof(struct sockaddr_in);
	struct sockaddr_in cliaddr, servaddr;
	char buf[MAXLINE];
	int nready;

	bzero(&servaddr, socklen);
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port = htons(servPort);

	listenfd = socket(AF_INET, SOCK_STREAM, 0);
	if (listenfd < 0) {
		perror("socket error");
	}

	int opt = 1;
	if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
		perror("setsockopt error");
	}

	if(bind(listenfd, (struct sockaddr *) &servaddr, socklen) == -1) {
		perror("bind error");
		exit(-1);
	}
	if (listen(listenfd, listenq) < 0) {
		perror("listen error");    
	}

	clients[0].fd = listenfd;
	clients[0].events = POLLIN;
	int i;
	for (i = 1; i< OPEN_MAX; i++) 
		clients[i].fd = -1; 
	maxi = listenfd + 1;

	printf("pollechoserver startup, listen on port:%d\n", servPort);
	printf("max connection is %d\n", OPEN_MAX);

	for ( ; ; )  {
		nready = poll(clients, maxi + 1, -1);
		//printf("nready is %d\n", nready);
		if (nready == -1) {
			perror("poll error");
		}
		if (clients[0].revents & POLLIN) {
			connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &socklen);
			sprintf(buf, "accept form %s:%d\n", inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port);
			printf(buf, "");

			for (i = 0; i < OPEN_MAX; i++) {
				if (clients[i].fd == -1) {
					clients[i].fd = connfd;
					clients[i].events = POLLIN;
					break;
				}
			}

			if (i == OPEN_MAX) {
				fprintf(stderr, "too many connection, more than %d\n", OPEN_MAX);
				close(connfd);
				continue;
			}

			if (i > maxi)
				maxi = i;

			--nready;
		}

		handle(clients, maxi, nready);
	}
}

void handle(struct pollfd* clients, int maxClient, int nready) {
	int connfd;
	int i, nread;
	char buf[MAXLINE];

	if (nready == 0)
		return;

	for (i = 1; i< maxClient; i++) {
		connfd = clients[i].fd;
		if (connfd == -1) 
			continue;
		if (clients[i].revents & (POLLIN | POLLERR)) {
			nread = read(connfd, buf, MAXLINE);//读取客户端socket流
			if (nread < 0) {
				perror("read error");
				close(connfd);
				clients[i].fd = -1;
				continue;
			}
			if (nread == 0) {
				printf("client close the connection");
				close(connfd);
				clients[i].fd = -1;
				continue;
			}

			write(connfd, buf, nread);//响应客户端  
			if (--nready