使用伪tty来做FTP

Question

我正在尝试使用以下代码使用伪tty进行FTP。 在数据包捕获中，我可以看到代码在请求命令用户中发送用户名root但它没有发送密码（即请求命令中没有发送请求参数：PASS）。有什么建议吗？

#!/usr/bin/perl

use warnings;
use strict;

use Net::Telnet;
use IO::Pty;
use POSIX 'setsid';
use Getopt::Long;

my $host = "192.168.1.121";
my $user = "root";

my $ssh = do_cmd('ftp',$host);

my $shell = Net::Telnet -> new(Fhopen => $ssh);

$shell -> binmode(1);
$shell -> cmd(String => 'root', Prompt => '/[a-z]/');
$shell -> cmd(String => 'password', Prompt => '/[a-z]/');

my @lines = $shell->cmd(String => 'ls', Prompt => '/[a-z]/');
print @lines;
print "\n";

sub do_cmd{
    my ($cmd,@args) = @_;

    my $pty = IO::Pty -> new;
    defined (my $child = fork);
    return $pty if $child;
    setsid();

    my $tty = $pty -> slave;
    close $pty;
    STDIN -> fdopen($tty,"<");
    STDOUT -> fdopen($tty,">");
    STDERR -> fdopen ($tty, ">");
    close $tty;

    $| = 1;
    exec $cmd,@args;
}