sub read_block {
   my ($fh) = @_;

   my $header = <$fh>;
   return undef if !defined($header);

   my @block = $header;

   do {
      my $line = <$fh>;
      die "Unexpected end of file\n" if !defined($line);
      chomp($line);

      push @block, $line;
   while ($line !~ /footer/);

   return \@block;
}

while (my $block = read_block($fh)) {
   ...process block...
}