/******* 服务器程序 (server.c) ************/
#include “stdio.h”
#include “stdlib.h”
#include “errno.h”
#include “sys/types.h”
#include “sys/socket.h”
#include “unistd.h”
#include “netinet/in.h”
#include “netdb.h”
int main(int argc,char *argv[])
{
int sockfd,new_fd;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
int sin_size,portnumber;
char hello[]=“Hello! Are You Fine?\n”;
if ( argc!=2 ) {
fprintf(stderr,“Usage:%s portnumber\a\n”,argv[0]);
exit(1);
}
if((portnumber=atoi(argv[1]))<0) {
fprintf(stderr,“Usage:%s portnumber\a\n”,argv[0]);
exit(1);
}
/* 服务器端开始建立socket描述符 */
if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1) {
fprintf(stderr,“Socket error:%s\n\a”,strerror(errno));
exit(1);
}
/* 服务器端填充 sockaddr结构 */
bzero(&server_addr,sizeof(struct sockaddr_in));
server_addr.sin_family=AF_INET;
server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
server_addr.sin_port=htons(portnumber);
/* 捆绑sockfd描述符 */
if(bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1) {
fprintf(stderr,“Bind error:%s\n\a”,strerror(errno));
exit(1);
}
/* 监听sockfd描述符 */
if(listen(sockfd,5)==-1) {
fprintf(stderr,“Listen error:%s\n\a”,strerror(errno));
exit(1);
}
while(1) {
/* 服务器阻塞,直到客户程序建立连接 */
sin_size=sizeof(struct sockaddr_in);
if((new_fd=accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size))==-1) {
fprintf(stderr,“Accept error:%s\n\a”,strerror(errno));
exit(1);
}
fprintf(stderr,“Server get connection from %s\n”,inet_ntoa(client_addr.sin_addr));
if(write(new_fd,hello,strlen(hello))==-1) {
fprintf(stderr,“Write Error:%s\n”,strerror(errno));
exit(1);
}
close(new_fd);
}
close(sockfd);
exit(0);
}