/*******服務器程序  TCPServer.c ************/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define WAITBUF 10
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! Socket communication world!\n";

 if(argc!=2)
 {
  fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]);
  exit(1);
 }
 /*端口號不對，退出*/
 if((portnumber=atoi(argv[1]))<0)
 {
  fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]);
  exit(1);
 }

/*服務器端開始建立socket描述符*/
 if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)  
 {
        fprintf(stderr,"Socket error:%s\n\a",strerror(errno));
        exit(1);
 }

/*服務器端填充 sockaddr結構*/ 
 bzero(&server_addr,sizeof(struct sockaddr_in));
 server_addr.sin_family=AF_INET;
/*自動填充主機IP*/
 server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
 server_addr.sin_port=htons(portnumber);
 
/*捆綁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);
 }
 
/*監聽sockfd描述符*/
 if(listen(sockfd, WAITBUF)==-1)
 {
        fprintf(stderr,"Listen error:%s\n\a",strerror(errno));
        exit(1);
 }

 while(1)
 {
        /*服務器阻塞，直到客戶程序建立連接*/
        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);
    }
	/*可以在這里加上自己的處理函數*/
        fprintf(stderr,"Server get connection from %s\n",
                                        inet_ntoa(client_addr.sin_addr));
        if(send(new_fd,hello,strlen(hello),0)==-1)
        {
         fprintf(stderr,"Write Error:%s\n",strerror(errno));
         exit(1);
        }
/*這個通信已經結束*/
       close(new_fd);
/*循環下一個*/  
  }
 close(sockfd);
 exit(0);
}