1、安装 daytime 服务：
apt-get install xinetd
chmod 777 /etc/xinetd.d/daytime
vim /etc/xinetd.d/daytime
把两个 disable = yes ,改成 disable = no
/etc/init.d/xinetd restart
2、timeserver.cpp:
#include <time.h> #include <netinet/in.h> #include <string.h> #include <stdio.h> #include <unistd.h> #define LISTENQ 1024 int main(int argc, char** argv) { int listenfd,connfd; sockaddr_in servaddr; char buff[1024]; time_t ticks; listenfd = socket(AF_INET,SOCK_STREAM,0); bzero(&servaddr,sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = htonl(INADDR_ANY); servaddr.sin_port = htons(2013); bind(listenfd,(sockaddr*)&servaddr,sizeof(servaddr)); listen(listenfd,LISTENQ); for(;;) { connfd = accept(listenfd,(sockaddr*)NULL,NULL); ticks = time(NULL); snprintf(buff,sizeof(buff),"%.24s\r\n",ctime(&ticks)); write(connfd,buff,strlen(buff)); //#include <unistd.h> close(connfd); } }
3、timeclient.cpp:
#include <iostream> #include <netinet/in.h> #include <string.h> #include <arpa/inet.h> #include <stdio.h> int main(int argc, char **argv) { int sockfd,n; char recvline[1024]; sockaddr_in servaddr; //#include <netinet/in.h> if(argc != 2) { std::cout<<"usage: a.out <IP>"<<std::endl; return -1; } if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0) //#include <sys/socket.h> { std::cout<<"socket error."<<std::endl; return -1; } bzero(&servaddr, sizeof(servaddr)); //#include <cstring> servaddr.sin_family = AF_INET; servaddr.sin_port = htons(2013); if(inet_pton(AF_INET,argv[1],&servaddr.sin_addr) <= 0) // #include <arpa/inet.h> { std::cout<<"inet_pton error"<<std::endl; return -1; } if(connect(sockfd, (sockaddr*)&servaddr,sizeof(servaddr)) < 0) { std::cout<<"connect error"<<std::endl; return -1; } while( (n = read(sockfd, recvline, 1023)) > 0) { recvline[n] = 0; if(fputs(recvline, stdout) == EOF) //#include <stdio.h> { std::cout<<"fputs error"<<std::endl; } } if(n < 0) { std::cout<<"read error"<<std::endl; } }