LinuxIO多路复用之poll

最新推荐文章于 2024-11-10 22:48:56 发布

qq_28110727

最新推荐文章于 2024-11-10 22:48:56 发布

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分类专栏： Linux

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本文介绍了一个简易的TCP服务器实现，该服务器使用poll进行事件监听，并能够处理客户端连接请求及数据读写。通过创建socket并绑定地址，然后监听客户端连接，利用poll机制等待就绪事件发生，实现了客户端连接接受和数据交互。

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#include <sys/types.h>
#include <poll.h>
#include <sys/socket.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>

#define SERV_PORT 8080
#define MAXSIZE 1024
#define MAXLINE 64

void sys_err(const char *fun_str,int exitno)
{
	perror("fun_str");
	exit(exitno);
}

int main()
{
	int sockfd, listenfd, connfd;
	struct sockaddr_in serv_addr,cli_addr;
	int ret;
	socklen_t cli_len;
	int len;
	int nready;
	char buf[MAXSIZE];
	struct pollfd client[MAXSIZE];
	int i=0,maxi=0;
	char addr[MAXLINE];
	
	listenfd = socket(AF_INET, SOCK_STREAM, 0);
	if(listenfd<0)
	{
		sys_err("socket",-1);
	}

	bzero(&serv_addr, sizeof(serv_addr));

	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	serv_addr.sin_port = htons(SERV_PORT);

	ret = bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
	if(ret <0)
	{
		sys_err("bind",-2);
	}
	
	ret = listen(listenfd,20);
	if(ret <0 )
	{
		sys_err("listen",-3);
	}

	client[0].fd = listenfd;
	client[0].events = POLLIN;

	for(i=1; i<MAXSIZE; i++)
	{
		client[i].fd = -1;
	}
	printf("accept client connect\n");
	while(1)
	{
		nready = poll(client, maxi+1, -1);
		if(nready <0)
		{
			sys_err("poll",-4);
		}
		//new connection
		if(client[0].revents & POLLIN)
		{
			cli_len = sizeof(cli_addr);
			connfd = accept(listenfd, (struct sockaddr *)&cli_addr, &cli_len);
			if(connfd <0)
			{
				sys_err("accept",-5);
			}
			printf("receive from ip %s port %d\n",
					inet_ntop(connfd, &serv_addr.sin_addr.s_addr, addr, sizeof(addr)), ntohs(serv_addr.sin_port));
			
			for(i=1; i<MAXSIZE; i++)
			{
				if(client[i].fd <0)
				{
					client[i].fd = connfd;
					break;
				}
			}

			if(i == MAXSIZE)
			{
				printf("too many clients\n");
				exit(0);
			}
			
			client[i].events = POLLIN;
		
			if(i >maxi)
				maxi = i;


			if(--nready == 0)
				continue;
		}
			for(i=1; i<=maxi; i++)
			{
				sockfd = client[i].fd;
				if(sockfd<0)
					continue;
				else
				{
					len = read(sockfd, buf, sizeof(buf));
					if(len <0)
						sys_err("read",-6);
					else if(0 == len)
					{
						close(connfd);
						client[i].fd = -1;
						printf("client[%d] close\n",i);
					}
					else
					{
						ret = write(sockfd, buf, len);
						if(ret<0)
						{
							sys_err("write",-7);
						}
					}
				}
				if(--nready == 0)
					break;
			}
	}
	close(listenfd);
	return 0;
}