Remote Execute Function (Unix REXEC)

Problem/Question/Abstract:

Remote Execute Function (Unix REXEC)

Answer:

This function will execute a command to a Unix box (or any TCP connection that supports REXEC - port 512) and return the display results in a file. I currently use it on HP and SUN systems.

The parameters to RExec() are

  HostIP                                 : string               // eg. '196.11.121.160'          
  UserID                                 : string               // eg. 'root'
  Password                         : string                          // eg. 'fraqu34'
  Command                         : string                          // eg. 'export TERM=vt100; dv'
  ResultFilename         : string                           // eg. 'c:\temp\uxresult.txt'

The function returns true if sucessful, else false.

The command may contain multiple statements separated by semi-colons. REMEMBER : REXEC does not run the user .profile, so NO user environments are set. You can export  any environment settings in this parameter.

eg. 'export TERM=vt100; export APP=baan; run_mycommand'

An example of use is ....
(change to directory /var and return a dir listing and return results in file c:\temp\ux.txt)

procedure TForm1.Button1Click(Sender: TObject);
begin
  RExec('196.11.121.162',
    'root', 'passwd342',
    'cd /var; ls -1',
    'c:\temp\ux.txt');

  Memo1.Lines.LoadFromFile('c:\temp\ux.txt');
end;


uses ScktComp;

function RExec(const HostIP: string; const UserID: string;
  const Password: string; const Command: string;
  const ResultFilename: string): boolean;
var
  TCP: TClientSocket;
  i: integer;
  TxOut: file;
  Buffer, Cr, Lf: byte;
  Failed: boolean;
begin
  Failed := true; // Assume initial error state
  Cr := 13; // Carriage Return Char
  Lf := 10; // Line Feed Char
  TCP := TClientSocket.Create(nil);

  try
    TCP.Address := HostIP;
    TCP.ClientType := ctBlocking;
    TCP.Port := 512; // REXEC port
    TCP.Open;

    // Give time to connect
    for i := 1 to 500 do
      if not TCP.Active then
        Sleep(100)
      else
        break;

    // If TCP opened OK then send the command to host
    // and write results to specified file
    if TCP.Active then
    begin
      AssignFile(TxOut, ResultFileName);
      Rewrite(TxOut, 1);
      TCP.Socket.SendText('0' + #0);
      TCP.Socket.SendText(UserID + #0);
      TCP.Socket.SendText(Password + #0);
      TCP.Socket.SendText(Command + #0);
      TCP.Socket.SendText(#13);
      Sleep(20); // Give a gap to respond

      // Wait for resonse from Host
      // You may want to check for timeout here using
      // a TTimer. My complete function does this, but
      // have omitted for sake of clarity.
      while (TCP.Socket.ReceiveBuf(Buffer, 1) <> 1) do
        Application.ProcessMessages;

      // Write host byte stream to file
      while TCP.Socket.ReceiveBuf(Buffer, 1) = 1 do
      begin
        if (Buffer = 10) then
        begin
          BlockWrite(TxOut, Cr, 1);
          BlockWrite(TxOut, Lf, 1);
        end
        else
          BlockWrite(TxOut, Buffer, 1);
      end;

      TCP.Close;
      CloseFile(TxOut);
      Failed := false;
    end;
  finally
    TCP.Free;
  end;

  Result := not Failed;
end;