freebsd-update from script without tty

Ben Morrow ben at
Fri Jun 20 19:23:57 UTC 2014

Quoth John Nielsen <lists at>:
> I have a script that builds virtual FreeBSD disk images. After it
> populates the base system it runs "freebsd-update -b ${MOUNTPOINT} ..."
> to update the image with the latest security patch release.
> If I run the script from a terminal it works fine. However if I try to
> run it from our user-friendly web interface (which spawns the script in
> the background with no tty) the freebsd-update step fails:
> # UNAME_r=10.0-RELEASE freebsd-update -b /mnt/chroot fetch
> freebsd-update fetch should not be run non-interactively.
> Run freebsd-update cron instead.
> I understand and appreciate the use case for 'freebsd-update cron' but
> in this case my script is running because a user requested and is
> waiting for it, and a delay of up to an hour won't really fly.
> Can anyone suggest a workaround?

The obvious answer would be to run it on a pty. If you can't easily do
this from your script directly, something like this might do:


    use IO::Pty;
    use IO::Select;

    my $pt = IO::Pty->new;
    my $sl = $pt->slave;

    unless (my $kid = fork) {
        close $pt;
        open STDIN, "<&", $sl;
        open STDOUT, ">&", $sl;
        open STDERR, ">&", $sl;
        close $sl;
        exec @ARGV;

    close $sl;
    my $sel = IO::Select->new($pt);
    $/ = \4096; $| = 1;

    while (1) {
        $_ = <$pt>;
        defined or last;

    waitpid $kid, 0;
    exit $?>>8 ? $?>>8 : $? ? 1 : 0;

Add proper error checking / signal handling / etc. to taste.


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