use threads;
use Socket     qw( AF_UNIX SOCK_STREAM PF_UNSPEC );
use IO::Handle qw( );

sub _pipe {
    socketpair($_[0], $_[1], AF_UNIX, SOCK_STREAM, PF_UNSPEC)
        or return undef;
    shutdown($_[0], 1);  # No more writing for reader
    shutdown($_[1], 0);  # No more reading for writer
    return 1;
}

sub sockify_stdin {
    open(my $real_stdin, '<&', *STDIN)
        or die("Can't dup STDIN: $^E\n");
    _pipe(*STDIN, my $stdin_w)
        or die("Can't create socketpair: $^E\n");
    $stdin_w->autoflush(1);

    async {
        close(STDIN); # Close this threads's copy.
        print $stdin_w $_ while <$real_stdin>;
        close($stdin_w);
    }->detach();

    close($stdin_w); # Close this threads's copy.
}