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

# OMIT: initialize some useful variables...

# Here everything gets called. These subroutines are defined below.
_log _begin;
    $settings = read_config("/etc/backup.conf");
    create_archive($settings->{archive});
    upload_archive($settings->{FTP});
    tape_archive($settings->{tape});
    delete_temp_files();
_log _end;

#
# send the files to tape. We use the rewinding device, because we
# don't really care about putting several archives on the same tape. 
# We also eject the tape because we want a different tape for each 
# day of the week.
sub tape_archive {
    my $conf = shift or return; # are we configured to tape stuff?
    my ($rdev, @tapeables) = 
        ($conf->{'rdev'}, @{$conf->{'tapeables'}});
    push @tapeables, $tarball if ($settings->{'archive'});
    # With the tape out, the following ought to _barf. But it doesn't.
    undef $!;
    system("tar --ignore-failed-read -cf $rdev @tapeables")
        and _barf "couldn't write to tape. Error $? : $! ";
    # Even if the previous line doesn't _barf, surely this one must,
    # right? Wrong.
    undef $!;
    system("mt -f $rdev offline")
         and _barf "couldn't eject tape. Error $? : $! ";
    push @deleteables, @tapeables;
}

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# Below this point are housekeeping and logging subs, so  #
# feel free to skip to the bottom                         #

# logging subs
sub _begin {
    chomp (my $now = `date`);
    return "-----\nstarting backup on $hostname at $now \n";
}
sub _log { 
    # OMIT: log stuff to file and return what was logged
}
sub _barf {
    my $msg = _log shift() .$/. _end();
    _mail( $settings->{mail}, $msg);
    die $msg;
}
sub _mail {
    my $conf = shift or return; # are we configured to mail stuff?
    use Net::SMTP;
    # OMIT: mail errors to the admin
}
sub _end {
    chomp (my $now = `date`);
    return "ended at $now \n-----\n";
}

# Read in the config file using Parse::PlainConfig
sub read_config {
    use Parse::PlainConfig;
    # OMIT: read settings from file and return a hashref
}
sub is_true($) { # used by read_config
    return defined $_[0] && $_[0] !~ /^(false|no|0)$/;
}
sub create_archive { # The first step is to create a temporary archive in /tmp/.
    # OMIT: we're writing to file. No problem here.
}
sub dump_into_file {
    # OMIT: turn the list of sources into an array we can send to tar
}
sub upload_archive {
    # OMIT: irrelevant
}
sub delete_temp_files { # clean up our temp directory.
    # OMIT: housekeeping code
}

__END__