server.cpp

#include<sys/types.h>
#include<sys/socket.h>
#include<unistd.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/wait.h>
#include<strings.h>
#include<errno.h>
#include<poll.h>
#define IPADDRESS "127.0.0.1"
#define PORT 6666
#define MAXLINE 1024
#define LISTENQ 5
#define OPEN_MAX 1000
#define INFTIM -1

int bind_and_listen()
{
	int serverfd;
	struct sockaddr_in my_addr;
	unsigned int sin_size;
	if((serverfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	{
		perror("socket");
		return -1;
	}
	printf("socket ok\n");
	my_addr.sin_family = AF_INET;
	my_addr.sin_port = htons(PORT);
	my_addr.sin_addr.s_addr = INADDR_ANY;
	bzero(&(my_addr.sin_zero), 0);
	if(bind(serverfd, (struct sockaddr*)&my_addr, sizeof(struct sockaddr)) == -1)
	{
		perror("bind");
		return -2;
	}
	printf("bind ok\n");
	if(listen(serverfd, LISTENQ) == -1)
	{
		perror("listen");
		return -3;
	}
	printf("listen ok\n");
	return serverfd;
}

void do_poll(int listenfd)
{
	int connfd, sockfd;
	struct sockaddr_in cliaddr;
	socklen_t cliaddrlen;
	struct pollfd clientfds[OPEN_MAX];      //可接受的client最大值
	int maxi;
	int i;
	int nready;
	clientfds[0].fd = listenfd;
	clientfds[0].events = POLLIN;
	for(i = 1; i<OPEN_MAX; i++)
		clientfds[i].fd = -1;
	maxi = 0;
	//初始化工作完成
	while(1)
	{
		nready = poll(clientfds, maxi+1, INFTIM);
		if(nready == -1)
		{
			perror("poll error:");
			exit(1);
		}
		if(clientfds[0].revents & POLLIN)
		{
			cliaddrlen = sizeof(cliaddr);
			if((connfd = accept(listenfd, (struct sockaddr*)&cliaddr, &cliaddrlen)) == -1)
			{
				if(errno == EINTR)
					continue;
				else
				{
					perror("accept error:");
					exit(1);
				}
			}
			fprintf(stdout, "accept a new client:%s:%d\n", inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port);
			for(i = 1; i<OPEN_MAX; i++)
			{
				if(clientfds[i].fd<0)
				{
					clientfds[i].fd = connfd;
					break;
				}
			}
			if(i == OPEN_MAX)
			{
				fprintf(stderr, "too many clients.\n");
				exit(1);
			}
			clientfds[i].events = POLLIN;
			maxi = (i>maxi?i:maxi);
			if(--nready<=0)   //当前准备好的只有serverfd
				continue;
		}
		
		char buf[MAXLINE];
		memset(buf, 0, MAXLINE);
		int readlen = 0;
		for(i = 1; i<maxi; i++)    //第0个是监听端口
		{
			if(clientfds[i].fd<0)
				continue;
			if(clientfds[i].revents & POLLIN)
			{
				readlen = read(clientfds[i].fd, buf, MAXLINE);
				if(readlen == 0)
				{
					close(clientfds[i].fd);
					clientfds[i].fd = -1;
					continue;
				}
				printf("msg is:");
				write(STDOUT_FILENO, buf, readlen);
				write(clientfds[i].fd, buf, readlen);  //发回去
			}
		}
	}
}
int main(int argc, char* argv[])
{
	int listenfd = bind_and_listen();
	if(listenfd<0)
	{
		return 0;
	}
	do_poll(listenfd);
	return 0;
}