/*?header?files?*/
#include	
#include	
#include		/*?getservbyname（）?gethostbyname（）?*/
#include		/*?for?definition?of?errno?*/
#include????
#include????
#include????
#include????
#include????
/*?define?macros*/
#define?MAXBUF	1024
#define?STDIN_FILENO	0
#define?STDOUT_FILENO	1

/*?define?FTP?reply?code?*/
#define?USERNAME	220
#define?PASSWORD	331
#define?LOGIN		230
#define?PATHNAME	257
#define?CLOSEDATA	226
#define?ACTIONOK	250
#define?FAIL????????550

/*?DefinE?global?variables?*/
char	*host;		/*?hostname?or?dotted-decimal?string?*/
char	*port;
char	*rbuf?*rbuf1;		/*?pointer?that?is?malloc‘ed?*/
char	*wbuf?*wbuf1;		/*?pointer?that?is?malloc‘ed?*/
struct??sockaddr_in	servaddr;
char????*rbuf2?*rbuf3;
int	????cliopen（char?*host?char?*port）;
void	strtosrv（char?*?char?*?char?*）;
void	cmd_tcp（int?sockfd）;
void	ftp_list（int?sockfd）;
void	ftp_get（int?sck?char?*pDownloadFileName_s）;
void	ftp_put?（int?sck?char?*pUploadFileName_s）;
void????ftp_help（）;


int
main（int?argc?char?*argv[]）
{
	int	fd;
????struct?hostent?*h;
????
	if?（0?!=?argc-2）
	{
		printf（“%s\n““missing?“）;
		exit（0）;
	}

	host?=?argv[1];
	port?=?“21“;

	//code?here:?Allocate?the?read?and?write?buffers?before?open（）.
????rbuf?=?（char?*）malloc（MAXBUF）;
????rbuf1?=?（char?*）malloc（MAXBUF）;
????wbuf?=?（char?*）malloc（MAXBUF）;
????wbuf1?=?（char?*）malloc（MAXBUF）;
????rbuf2?=?（char?*）malloc（MAXBUF）;
????rbuf3?=?（char?*）malloc（MAXBUF）;
????
????fd?=?cliopen（host?port）;
???
	cmd_tcp（fd）;

	exit（0）;
}


/*?Establish?a?TCP?connection?from?client?to?server?*/
int
cliopen（char?*host?char?*port）
{
??int?sd?rc?i;
??struct?hostent?*h;
??short?port_int?=?atoi（port）;
??
??h?=?gethostbyname（host）;
??
??servaddr.sin_family?=?AF_INET;
??memcpy（（char?*）?&servaddr.sin_addr.s_addr?h->h_addr_list[0]?h->h_length）;
??servaddr.sin_port?=?htons（port_int）;
??//printf（“Connecting?%s:%d.......“?inet_ntoa（servaddr.sin_addr）?port_int）;
?			
??
??/*?create?socket?*/
??sd?=?socket（AF_INET?SOCK_STREAM?0）;
??
??if（sd<0）?{
????perror（“cannot?open?socket?“）;
????exit（1）;
??}
????
??/*?connect?to?server?*/
??rc?=?connect（sd?（struct?sockaddr?*）?&servaddr?sizeof（servaddr））;
??if（rc<0）?{
????perror（“Cannot?connect?“）;
????exit（1）;
??}

??return?sd;?
}


/*
???Compute?server‘s?port?by?a?pair?of?integers?and?store?it?in?char?*port
???Get?server‘s?IP?address?and?store?it?in?char?*host
*/
void
strtosrv（char?*str?char?*host?char?*port）
{
????????int	i;
	????char?*p;
????????char?*ip;
	????char?*portNum;

	????
????????p?=?（char?*）malloc（300）;
??????	??????????	
???	????sprintf（p“%s“strchr（str‘（‘））;
???	????
???	?????ip=++p;
???	????
???	????
		for（i=0;i<4;i++）	
		{
			p=strchr（ip‘‘）;
			*p=‘.‘;
		}
		*p=‘\0‘;
		
		sprintf（host“%s“ip）;
		?
		
		portNum?=?++p;	
		p?=?strchr（portNum‘‘）;	
		i?=?atoi（portNum）?*?256?+?atoi（++p）;
		sprintf（portNum“%d“i）;
		sprintf（port“%s“portNum）;
		
	??????????????????????