leapsec-check.pl

#!/usr/bin/env perl
# Check valitidy of a leap-seconds.list file.
# klg, Jan 2014
use strict;
use open ':std', IN => ':bytes';
use Digest::SHA 'sha1';
use Time::Local 'timegm';

use constant EPOCH => timegm 0, 0, 0, 1, 0, 1900;

my ($v, $b, $h);
shift @ARGV if $v = @ARGV && $ARGV[0] =~ /^--?v/i;

while (<>) {
  if ($v && m/#\$\s*([0-9]++)/) {
    printf "Last update:     %s UTC\n",
      scalar gmtime EPOCH + $1;
  }
  if (m/#@\s*([0-9]++)/) {
    my $exp = EPOCH + $1;
    if (time > $exp) {
      printf STDERR "File EXPIRED on: %s UTC\n",
        scalar gmtime $exp;
      exit 1;
    }
    printf "File expires on: %s UTC\n",
      scalar gmtime $exp if $v;
  }
  $h = $1 if m/#h\s*(.++)/;
  s/#(\$|@|.*$)//, s/[^0-9]//g;
  $b .= $_;
}

$b = sha1($b);
printf "#h %x %x %x %x %x\n", unpack 'N5', $b if $v;

if (defined $h) {
  $h = pack 'N5', map hex, $h =~ m/([0-9a-f]+)/gi;
  if ($b ne $h) {
    printf STDERR "File corrupted!\n";
    exit 1;
  }
} elsif ($v) {
  printf STDERR "Checksum missing.\n";
}

1;