text: #!perl -w
  
  use strict;
  use warnings;
  
  use Opcode qw(opset opset_to_ops opdesc);
  
  my $plperl_opmask_h = shift
    or die "Usage: $0 <output_filename.h>\n";
  
  my $plperl_opmask_tmp = $plperl_opmask_h . "tmp";
  END { unlink $plperl_opmask_tmp }
  
  open my $fh, ">", "$plperl_opmask_tmp"
    or die "Could not write to $plperl_opmask_tmp: $!";
  
  printf $fh "#define PLPERL_SET_OPMASK(opmask) \\\n";
  printf $fh "  memset(opmask, 1, MAXO);\t/* disable all */ \\\n";
  printf $fh "  /* then allow some... */                       \\\n";
  
  my @allowed_ops = (
  
  	# basic set of opcodes
  	qw[:default :base_math !:base_io sort time],
  
  	# require is safe because we redirect the opcode
  	# entereval is safe as the opmask is now permanently set
  	# caller is safe because the entire interpreter is locked down
  	qw[require entereval caller],
  
  	# These are needed for utf8_heavy.pl:
  	# dofile is safe because we redirect the opcode like require above
  	# print is safe because the only writable filehandles are STDOUT & STDERR
  	# prtf (printf) is safe as it's the same as print + sprintf
  	qw[dofile print prtf],
  
  	# Disallow these opcodes that are in the :base_orig optag
  	# (included in :default) but aren't considered sufficiently safe
  	qw[!dbmopen !setpgrp !setpriority],
  
     # custom is not deemed a likely security risk as it can't be generated from
     # perl so would only be seen if the DBA had chosen to load a module that
     # used it. Even then it's unlikely to be seen because it's typically
     # generated by compiler plugins that operate after PL_op_mask checks.
     # But we err on the side of caution and disable it
  	qw[!custom],);
  
  printf $fh "  /* ALLOWED: @allowed_ops */ \\\n";
  
  foreach my $opname (opset_to_ops(opset(@allowed_ops)))
  {
  	printf $fh qq{  opmask[OP_%-12s] = 0;\t/* %s */ \\\n},
  	  uc($opname), opdesc($opname);
  }
  printf $fh "  /* end */ \n";
  
  close $fh
    or die "Error closing $plperl_opmask_tmp: $!";
  
  rename $plperl_opmask_tmp, $plperl_opmask_h
    or die "Error renaming $plperl_opmask_tmp to $plperl_opmask_h: $!";
  
  exit 0;
  