linux poll实现简易服务器

女爷i 2022-02-25 16:46 248阅读 0赞

#include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <errno.h>
    #include <unistd.h>
    #include <time.h>
    #include <sys/socket.h>
    #include <poll.h>
    #include <limits.h>		/*for OPEN_MAX*/
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <netdb.h>
    #include <fcntl.h>
    
    
    #ifndef OPEN_MAX
    #define OPEN_MAX 1024
    #endif
    
    #ifndef INFTIM
    #define INFTIM -1
    #endif
    
    #define PORT 8888
    #define MAX_LINE 2048
    #define LISTENQ 20
    
    
    int main(int argc , char **argv)
    {
    	int i, maxi, listenfd, connfd, sockfd;
    
    	int nready;
    	
    	ssize_t n, ret;
    		
    	struct pollfd client[OPEN_MAX];
    
    	char buf[MAX_LINE];
    
    	socklen_t clilen;
    
    	struct sockaddr_in servaddr , cliaddr;
    
    	/*(1) 得到监听描述符*/
    	listenfd = socket(AF_INET , SOCK_STREAM , 0);
    
    	/*(2) 绑定套接字*/
    	bzero(&servaddr , sizeof(servaddr));
    	servaddr.sin_family = AF_INET;
    	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    	servaddr.sin_port = htons(PORT);
    
    	bind(listenfd , (struct sockaddr *)&servaddr , sizeof(servaddr));
    
    	/*(3) 监听*/
    	listen(listenfd , LISTENQ);
    
    	/*(4) 设置poll*/
    	client[0].fd = listenfd;
    	client[0].events = POLLRDNORM;
    	for(i=1 ; i<OPEN_MAX ; ++i)
    	{
    		client[i].fd = -1;
    	}//for
    	maxi = 0;
    
    	/*(5) 进入服务器接收请求死循环*/
    	while(1)
    	{
    		nready = poll(client , maxi+1 , INFTIM);
    		
    		if(client[0].revents & POLLRDNORM)
    		{
    			/*接收客户端的请求*/
    			clilen = sizeof(cliaddr);
    
    			printf("\naccpet connection~\n");
    
    			if((connfd = accept(listenfd , (struct sockaddr *)&cliaddr , &clilen)) < 0)
    			{
    				perror("accept error.\n");
    				exit(1);
    			}//if		
    
    			printf("accpet a new client: %s:%d\n", inet_ntoa(cliaddr.sin_addr) , cliaddr.sin_port);
    			
    			/*将客户链接套接字描述符添加到数组*/
    			for(i=1 ; i<OPEN_MAX ; ++i)
    			{
    				if(client[i].fd < 0)
    				{
    					client[i].fd = connfd;
    					break;
    				}//if
    			}//for
    
    			if(OPEN_MAX == i)
    			{
    				perror("too many connection.\n");
    				exit(1);
    			}//if
    	
    			/*该描述符等待的事件*/
    			client[i].events = POLLRDNORM;
    			if(i > maxi)
    				maxi = i;
    
    			if(--nready < 0)
    				continue;
    		}//if
    			
    		for(i=1; i<=maxi ; ++i)
    		{
    			if((sockfd = client[i].fd) < 0)
    				continue;
    			/*该链接描述符实际发生的事件*/
    			if(client[i].revents & (POLLRDNORM | POLLERR))
    			{
    				/*处理客户请求*/
    				printf("\nreading the socket~~~ \n");
    				
    				bzero(buf , MAX_LINE);
    				if((n = read(sockfd , buf , MAX_LINE)) <= 0)
    				{
    					close(sockfd);				
    					client[i].fd = -1;
    				}//if
    				else{
    					printf("clint[%d] send message: %s\n", i , buf);
    					if((ret = write(sockfd , buf , n)) != n)	
    					{
    						printf("error writing to the sockfd!\n");
    						break;
    					}//if
    				}//else
    				if(--nready <= 0)
    					break;
    			}//if
    		}//for
    	}//while
    	exit(0);
    }