#!/usr/bin/perl

# sync_active.pl -- downloads authoritative active file from ISC and brings
#   local active file into sync with it

$active = "/var/typhoon/etc/active.text";
$control = "/var/typhoon/tools/sync_active/active.control";
$url = "http://open-systems.ufl.edu/mirrors/ftp.isc.org/pub/usenet/CONFIG/active.gz";
$work_dir = "/var/typhoon/tools/sync_active";
$reload_cmd = "/var/typhoon/bin/reload";
$log = "$work_dir/log";

my $current_hash, $add_hash;
my $num_removals = 0;

chdir $work_dir or die "couldn't change to working dir $work_dir!\n";

die "couldn't download $url!\n" if system "wget $url >/dev/null 2>&1";
die "couldn't gunzip active.gz!" if system "gunzip active.gz >/dev/null 2>&1";

open FILE, "<$active" or die "couldn't open $active!\n";
while (<FILE>) {
  @parts = split /\s/, $_;
  lc $parts[0];
  $current_hash{$parts[0]} = 1;
}
close FILE or die "couldn't close $active!\n";

open FILE, "active" or die "couldn't open active!\n";
while (<FILE>) {
  @parts = split /\s/, $_;
  lc $parts[0];
  if (exists $current_hash{$parts[0]}) {
    delete $current_hash{$parts[0]};
  } else {
    $add_hash{$parts[0]} = 1;
  }
}
close FILE or die "couldn't close active!\n";

open FILE, ">>$control" or die "couldn't open $control!\n";
open LOG, ">>$log";
$date = `date`;
print LOG $date;
foreach (keys %current_hash) {
  print FILE "-$_\n";
  print LOG "-$_\n";
  $num_removals++;
}
foreach (keys %add_hash) {
  print FILE "+$_\n";
  print LOG "+$_\n";
}
close FILE or die "couldn't close $control!\n";

if ($num_removals >= 100) {
  print LOG "number of removals exceeds 100 -- assuming something ".
	    "is broken\n\n";
  close LOG;
  unlink $control;
  rename "$work_dir/active", "$work_dir/active.broken";
  exit 1;
}

print LOG "\n\n";
close LOG;

`$reload_cmd`;

unlink "$work_dir/active" or die "couldn't unlink $work_dir/active!\n";