commands.c

用c写的ftp客户端源代码,可以在UNIX,Windows下编译通过,学习的好代码!

/* dftp: FTP client example
 * Copyright (c) 1996 by Donald C. Asonye
 * Email: [e-mail]
 *
 * commands.c.
 *
 * This and other files are hereby released	to the public for 
 * educational purposes.  You may redistribute this and other files
 * or routines as long as you are not compensated for it, and as 
 * long as this notice is included with it.  You may not use the 
 * released source codes in anyway commercial without permission.
 *
 * It'd be nice if you share your modifications with me and everyone
 * else.  I encourage you to make the code better as I am very busy.
 *
 * Share your knowledge :)
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "commands.h"
#include "extfuncs.h"

char szBuffer[1025]={0};  /* buffer used to read/write */
char szUser[20];          /* stores username */
char szPass[256];         /* stores user password */
extern int Connected;     /* flag for connect status */


/* 
 * CheckCommand
 * this is the main command parser.  it scans user input
 * and returns the correct command flag.  it's fairly 
 * straight forward.  just a bunch of strcmp & strncmp
 */
int CheckCommand(char *command)
{
    
    if( !strcmp(command,"pwd") )
	return PWD;
    if( !strncmp(command,"rhelp",5) )
	return RHELP;
    if( !strncmp(command,"help",4) )
	return HELP;
    if( !strncmp(command,"ls ",3) || !strcmp(command,"ls")
	|| !strcmp(command,"dir"))
	return LS;
    if( !strcmp(command,"cd") || !strncmp(command,"cd ",3) )
	return CD;
    if( !strcmp(command,"close"))
	return CLOSE;
    if( !strcmp(command,"quit") || !strcmp(command,"bye") ||
	!strcmp(command,"exit") )
	return QUIT;
    if( !strcmp(command,"open") || !strcmp(command,"o") ||
	!strncmp(command,"open ",5) || !strncmp(command,"o ",2) )
	return OPEN;
    if( !strcmp(command,"lls") || !strcmp(command,"ldir") )
	return LLS;
    if( !strcmp(command,"lcd") || !strncmp(command, "lcd ",4) )
	return LCD;
    if( !strcmp(command,"user") || !strncmp(command,"user ",5))
	return USER;
    if( !strcmp(command,"bin") || !strcmp(command,"binary") )
	return BINARY;
    if( !strcmp(command,"as") || !strcmp(command,"ascii") )
	return ASCII;
    if( !strncmp(command,"!",1) )
	return SHELL;
    if( !strncmp(command,"get ", 4) )
	return GET;
    if( !strncmp(command,"put ", 4) )
	return PUT;

    return -1;   /* unsupported command */
}

/*
 * DoOpen
 * this function is called when the o,open command is issued.
 * it connects to the requested host, and logs the user in
 *
 */
void DoOpen( char *command)
{
  char *szHost=NULL;  /* remote host */

   /* 
    * do not do anything if we are already connected.
    */
   if( Connected ) {
       printf("Already connected.  Close connection first.\n");
       fflush(stdout);
       return;
   }
   
   /*
    * extract the remote host from command line (if given ).
    * make a copy of the host name with strdup.
    */
   if(!strcmp(command,"open") || !strcmp(command,"o")) {

       printf("Host:"); fgets(szBuffer,1024,stdin);
       (void)strtok(szBuffer,"\n");
       szHost = (char *)strdup(szBuffer);;
   }
   else if( !strncmp(command,"open ",5))
	szHost = strdup(&command[5]);
   else if( !strncmp(command,"o ",2) )
	szHost = strdup(&command[2]);
   else
	szHost = strdup(command);


   printf("Connecting to %s\n",szHost);
   hControlSocket = ConnectToServer(szHost,"21");

#if (defined(WIN32) || defined(_WIN32) )
   Sleep(1);
#else
   sleep(1);
#endif

   if( hControlSocket > 0)  {
     printf("Connected to %s\n",szHost);
#if (defined(WIN32) || defined(_WIN32) )
   
	 sprintf(command,"dftp: Connected to %s ", szHost);

	 SetConsoleTitle(command);  /* set console window title */
#endif

     Connected = 1;         /* we ar now connected */
     GetReply();            /* get reply (welcome message) from server */
     DoLogin((char *)NULL); /* prompt for username and password */
     DoBinary();            /* default binary mode */
   }
   free(szHost); /* free the strdupped string */
}

/*
 * DoLogin
 * this function logs the user into the remote host.
 * prompts for username and password
 */
void DoLogin( char *command)
{
 char *User=NULL;
 
  if( command && *command)
     User=&command[5];

   if( Connected )  {

     /* 
      * ignore leading whitespace
      */
     while(User && (*User == ' ' || *User == '\t') && *User)
	 User++;
     /*
      * if user name was not provided via command line, read it in.
      */
     if(!User || !(*User) ) {
	printf("Login:"); fgets(szUser,20,stdin);
	User = szUser;
	(void)strtok(szUser,"\n");   /* remove '\n' */
     }

     /*
      * send user name & password to server  & get reply message
      */
     sprintf(szBuffer,"USER %s\r\n",User);
     SendControlMsg(szBuffer,strlen(szBuffer));
     GetReply();
     GetPassword( szPass );

     sprintf(szBuffer,"PASS %s\r\n",szPass);
     SendControlMsg(szBuffer,strlen(szBuffer));
     GetReply();
   }
   else
      printf("Not Connected.\n");
}

/*
 * DoClose
 * closes connection to the ftp server
 */
void DoClose( void )
{
   if( !Connected  ) {
     printf("Not Connected.\n");
    
   }
   else {
	   SendControlMsg("quit\r\n",6);
	   GetReply();
	   CloseControlConnection();
	   hControlSocket = -1;
#if (defined(WIN32) || defined(_WIN32) )
   
	   SetConsoleTitle("dftp: Connection closed");
#endif

	   Connected = 0;
   }

}

/*
 * DoList
 * perform directory listing i.e: ls
 */
void DoList( char *command)
{
   if( !Connected ) {
      printf("Not Connected.\n");
      return;
   }

   /*
    * obtain a listening socket
    */
   if( GetListenSocket() < 0) {
       printf("Cannot obtain a listen socket.\n");
       return;
   }
   
   /*
    * parse command
    */
   if( !strcmp(command,"ls") )  {
       sprintf(szBuffer,"NLST\r\n");
   }
   else if( !strcmp(command,"dir") ) 
       sprintf(szBuffer,"LIST\r\n");

   else if( !strncmp(command, "ls ",3)) {
       while( *command == ' ') command++;
       sprintf(szBuffer,"LIST %s\r\n",&command[3]);
   }
   /*
    * send command to server and get response
    */
   SendControlMsg(szBuffer,strlen(szBuffer));
   memset(szBuffer,0,1024);
   GetReply();

   /*
    * accept server's connection
    */
   if(AcceptConnection() < 0) {
      printf("Cannot accept connection.\n");
      return;
   }
   CloseListenSocket();       /* close listening socket */

   /*
    * display directory listing.
    */
   while( ReadDataMsg(szBuffer,1024) > 0) {
       fflush(stdout);
       printf(szBuffer);
       memset(szBuffer,0,1024);
   }
   /*
    * read response
    */
   (void)GetReply();

}

/*
 * DoCD
 * chang to another directory on the remote system
 */
void DoCD( char *command)
{
   char *dir=&command[2];

   if( !Connected ) {
       printf("Not Connected.\n");
       return;
   }

   /*
    * ignore leading whitespace
    */
   while( *dir && (*dir == ' ' || *dir == '\t') ) 
       dir++;

   /*
    * if dir is not specified, read it in
    */
   if( ! (*dir) ) {
      printf("Remote directory:");
      fgets(szBuffer,1024,stdin);
      (void)strtok(szBuffer,"\n");
      dir = (char *)strdup(szBuffer);
      while( *dir && (*dir) == ' ') 
       dir++;
      if( !(*dir) ) {
	printf("Usage: cd remote-directory\n");
	return;
      }
   }
   
   /*
    * send command to server and read response
    */
   sprintf(szBuffer, "CWD %s\r\n",dir);
   SendControlMsg(szBuffer,strlen(szBuffer));
   (void)GetReply();
}

/*
 * DoLCD
 * change directory on the local system
 */
void DoLCD( char *command)
{

   char *dir = &command[3];

   while(*dir && (*dir == ' ' || *dir == '\t') ) dir++;

   /*
    * if dir is not specified, then print the current dir
    */
   if( ! *dir ) {
      dir = getcwd((char *)NULL,256);
      if( !dir)
	perror("getcwd");
      else
	printf("Current directory is: %s\n",dir);
   }
   else {
      if( chdir(dir) < 0) 
	perror("chdir");
      else {
	dir = getcwd((char *)NULL,256);
	if( !dir)
	    perror("getcwd");
	else
	printf("Current directory is: %s\n",dir);
      }
   }
}

/*
 * DoLLS
 * perform local directory listing.  winqvt implements this, but
 * this is not supported by many systems.  it's not really needed
 * since we already have '!' command.  you can just do !ls or !dir.
 */
void DoLLS( char *command )
{
#if ( !defined(_WIN32) || !defined(WIN32) )
    system("ls");
#else
    system("dir");
#endif
}

/*
 * function to pass commands to the system, ie: dir.
 * this function gets called when '!' is encountered
 */
void DoShellCommand( char *command )
{
  command++;  /* ignore '!' */
#if ( !defined(_WIN32) || !defined(WIN32) )

    system(command);
#else
	if( !command || !*command)
		system("cmd");   /* have to fix this for win95 */
	else                     /* maybe i should use 'start' */
		system(command); /* programatically determine which */ 
#endif                           /* system we are on, then make the  */
				 /* appropriate call */
}


/*
 * DoBinary
 * set file transfer mode to binary
 */
void DoBinary()
{
  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
   sprintf(szBuffer, "TYPE I\r\n");
   SendControlMsg(szBuffer,strlen(szBuffer));
   GetReply();
   printf("File transfer modes set to binary.\n");
   bMode = BINARY;
}

/*
 * DoAscii
 * set file transfer mode to ascii text
 */
void DoAscii()
{
  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
   sprintf(szBuffer, "TYPE A\r\n");
   SendControlMsg(szBuffer,strlen(szBuffer));
   GetReply();
   printf("File transfer modes set to ascii.\n");
   bMode = ASCII;

}

/*
 * DoGet
 * retrieve a file from the remote host.  calls GetFile(..)
 */
void DoGet( char *command)
{

  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
  (void)strtok(command," ");
  GetFile(strtok((char *)NULL, " "));
}

/*
 * DoPut
 * send a file to the remote host.  calls PutFile(..)
 */
void DoPut( char *command )
{
  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
  (void)strtok(command," ");
  PutFile(strtok((char *)NULL, " "));
}

/*
 * DoRhelp
 * sends a help command to the server.
 */
void DoRhelp( char *command )
{
  char *szCommand;

  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
  (void)strtok(command," ");
  szCommand=strtok((char *)NULL, " ");

  if( szCommand && *szCommand )
     sprintf(szBuffer,"HELP %s\r\n",szCommand);
  else 
     sprintf(szBuffer, "HELP\r\n");
  
  SendControlMsg(szBuffer, strlen(szBuffer));
  GetReply();
}

/*
 * retrieves the current directory on the remote host
 */
void DoPWD()
{

  if( !Connected ) {
      printf("Not Connected.\n");
      return;
  }
  sprintf(szBuffer, "PWD\r\n");
  SendControlMsg(szBuffer,strlen(szBuffer));
  GetReply();
}