talk_to_yourself.pl

#!/usr/bin/perl
use warnings;
use strict;

use Socket;
use POSIX qw(dup2);

#my $program = "/usr/sbin/telnetd";
#my @progargs = qw(-h -E /usr/bin/yes);
my $program = "/usr/sbin/sshd";
my @progargs = qw(-i);

socketpair(my $rdr, my $wtr, AF_UNIX, SOCK_STREAM, PF_UNSPEC)
        or die("socketpair");
close(STDIN);
close(STDOUT);
if (dup2(fileno($rdr), 0) == -1) { die("dup2"); }
if (dup2(fileno($wtr), 1) == -1) { die("dup2"); }
close($rdr);
close($wtr);

exec $program, @progargs or die("exec");