client.c

设计服务器和客户端

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>
#include <time.h>
#include <resolv.h>
#define SERVPORT 3333
#define MAXDATASIZE 80

int main(int argc,char *argv[])
{
	int sockfd,sendbytes,recvbytes;
	int maxfd;
	int ffd;
	int ret;
	int i;
	char buf[MAXDATASIZE];
	char recvbuf[MAXDATASIZE];
	struct timeval tv;
	struct hostent *host;
	struct sockaddr_in serv_addr;
	fd_set rfds;
	
	if(argc < 2)
	{
		fprintf(stderr,"Please enter the server's hostname!\n");
		exit(1);
	}
	if((host=gethostbyname(argv[1]))==NULL)
	{
		perror("gethostbyname");
		exit(1);
	}
	if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		perror("socket");
		exit(1);
	}
	
	serv_addr.sin_family=AF_INET;
	serv_addr.sin_port=htons(SERVPORT);
	serv_addr.sin_addr=*((struct in_addr *)host->h_addr);
	bzero(&(serv_addr.sin_zero),8);
	
	if(connect(sockfd,(struct sockaddr *)&serv_addr,\
		sizeof(struct sockaddr))==-1)
	{
		perror("connect");
		exit(1);
	}
	
	while(1)
	{
		FD_ZERO(&rfds);
		FD_SET(0,&rfds);
		maxfd=0;
		FD_SET(sockfd,&rfds);
		if(maxfd<sockfd)
		{
			maxfd=sockfd;
		}
	
		tv.tv_sec=1;
		tv.tv_usec=0;
		
		ret=select(maxfd+1,&rfds,NULL,NULL,&tv);		
		if (ret==-1)
		{
			perror("select error:\n");
			exit(1);
		}
		else if (ret==0)
		{
			continue;
		}
		else
		{
			if (FD_ISSET(0,&rfds))
			{
				fgets(buf,10,stdin);
				sendbytes=send(sockfd,buf,sizeof(buf),0);
				if(sendbytes==-1)
				{
					perror("send error");
					exit(1);
				}
				for(i=strlen(buf);i>=0;i--)
				{
					buf[i+2]=buf[i];
				}
				buf[0]='.';
				buf[1]='/';
				//break;
			}
			if(FD_ISSET(sockfd,&rfds))
			{
				recvbytes=recv(sockfd,recvbuf,MAXDATASIZE,0);
				if(recvbytes==-1)
				{
					perror("recv file");
					exit(1);
				}
				ffd=open("./newfile",O_WRONLY|O_CREAT,0600);
				if(ffd==-1)
				{
					printf("create file error\n");
					exit(1);
				}
				write(ffd,recvbuf,MAXDATASIZE);
				memset(recvbuf,0,sizeof(recvbuf));
				break;
			}
		}
	}
	close(sockfd);
	return 0;
}