#include <sys/types.h>#include <sys/socket.h>#include <stdio.h>#include <stdlib.h>#include <sys/stat.h>#include <fcntl.h>#include <errno.h>#include <string.h>#include <unistd.h>#include <netinet/in.h>#include <pthread.h>#define SERVPORT 3333#define BACKLOG 10#define MAX_CONNECTED_NO 10#define MAXDATASIZE 80int main(){	struct sockaddr_in server_sockaddr,client_sockaddr;	int sin_size,recvbytes;	int sockfd,client_fd,c_client_fd;	int ffd;	int i;	int ret;	char recvbuf[MAXDATASIZE];	char buf[MAXDATASIZE];		if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1)	{		perror("socket");		exit(1);	}	printf("socket success!,sockfd=%d\n",sockfd);		server_sockaddr.sin_family=AF_INET;	server_sockaddr.sin_port=htons(SERVPORT);	server_sockaddr.sin_addr.s_addr=INADDR_ANY;	bzero(&(server_sockaddr.sin_zero),8);		if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1)	{		perror("bind");		exit(1);	}	printf("bind success!\n");		if(listen(sockfd,BACKLOG)==-1)	{		perror("listen");		exit(1);	}	printf("listening....\n");		if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1)	{		perror("accept");		exit(1);	}		c_client_fd=client_fd;		if((recvbytes=recv(client_fd,recvbuf,MAXDATASIZE,0))==-1)	{		perror("recv");		exit(1);	} 	//printf("received a connection :%s\n",recvbuf);		for(i=strlen(recvbuf);i>=0;i--)	{		recvbuf[i+2]=recvbuf[i];	}	recvbuf[0]='.';	recvbuf[1]='/'; 	//printf("received a connection :%s\n",recvbuf);		ffd=open(recvbuf,O_RDONLY|O_EXCL,0400);	if(ffd==-1)	{			ret=send(client_fd,"file not exsit",15,0);		printf("no file\n");		if(ret==-1)		{			perror("send");			exit(1);		}		return 0;	}	while(read(ffd,buf,80))	{		ret=send(c_client_fd,buf,sizeof(buf),0);		if(ret==-1)		{			perror("send file");			exit(1);		}		memset(buf,0,sizeof(buf));	}	close(ffd);	printf("file tansferred!\n");	close(sockfd);	return 0;}