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+package Opcode;
+
+use 5.006_001;
+
+use strict;
+
+our($VERSION, @ISA, @EXPORT_OK);
+
+$VERSION = "1.11";
+
+use Carp;
+use Exporter ();
+use XSLoader ();
+
+BEGIN {
+ @ISA = qw(Exporter);
+ @EXPORT_OK = qw(
+ opset ops_to_opset
+ opset_to_ops opset_to_hex invert_opset
+ empty_opset full_opset
+ opdesc opcodes opmask define_optag
+ opmask_add verify_opset opdump
+ );
+}
+
+sub opset (;@);
+sub opset_to_hex ($);
+sub opdump (;$);
+use subs @EXPORT_OK;
+
+XSLoader::load 'Opcode', $VERSION;
+
+_init_optags();
+
+sub ops_to_opset { opset @_ } # alias for old name
+
+sub opset_to_hex ($) {
+ return "(invalid opset)" unless verify_opset($_[0]);
+ unpack("h*",$_[0]);
+}
+
+sub opdump (;$) {
+ my $pat = shift;
+ # handy utility: perl -MOpcode=opdump -e 'opdump File'
+ foreach(opset_to_ops(full_opset)) {
+ my $op = sprintf " %12s %s\n", $_, opdesc($_);
+ next if defined $pat and $op !~ m/$pat/i;
+ print $op;
+ }
+}
+
+
+
+sub _init_optags {
+ my(%all, %seen);
+ @all{opset_to_ops(full_opset)} = (); # keys only
+
+ local($_);
+ local($/) = "\n=cut"; # skip to optags definition section
+ <DATA>;
+ $/ = "\n="; # now read in 'pod section' chunks
+ while(<DATA>) {
+ next unless m/^item\s+(:\w+)/;
+ my $tag = $1;
+
+ # Split into lines, keep only indented lines
+ my @lines = grep { m/^\s/ } split(/\n/);
+ foreach (@lines) { s/--.*// } # delete comments
+ my @ops = map { split ' ' } @lines; # get op words
+
+ foreach(@ops) {
+ warn "$tag - $_ already tagged in $seen{$_}\n" if $seen{$_};
+ $seen{$_} = $tag;
+ delete $all{$_};
+ }
+ # opset will croak on invalid names
+ define_optag($tag, opset(@ops));
+ }
+ close(DATA);
+ warn "Untagged opnames: ".join(' ',keys %all)."\n" if %all;
+}
+
+
+1;
+
+__DATA__
+
+=head1 NAME
+
+Opcode - Disable named opcodes when compiling perl code
+
+=head1 SYNOPSIS
+
+ use Opcode;
+
+
+=head1 DESCRIPTION
+
+Perl code is always compiled into an internal format before execution.
+
+Evaluating perl code (e.g. via "eval" or "do 'file'") causes
+the code to be compiled into an internal format and then,
+provided there was no error in the compilation, executed.
+The internal format is based on many distinct I<opcodes>.
+
+By default no opmask is in effect and any code can be compiled.
+
+The Opcode module allow you to define an I<operator mask> to be in
+effect when perl I<next> compiles any code. Attempting to compile code
+which contains a masked opcode will cause the compilation to fail
+with an error. The code will not be executed.
+
+=head1 NOTE
+
+The Opcode module is not usually used directly. See the ops pragma and
+Safe modules for more typical uses.
+
+=head1 WARNING
+
+The authors make B<no warranty>, implied or otherwise, about the
+suitability of this software for safety or security purposes.
+
+The authors shall not in any case be liable for special, incidental,
+consequential, indirect or other similar damages arising from the use
+of this software.
+
+Your mileage will vary. If in any doubt B<do not use it>.
+
+
+=head1 Operator Names and Operator Lists
+
+The canonical list of operator names is the contents of the array
+PL_op_name defined and initialised in file F<opcode.h> of the Perl
+source distribution (and installed into the perl library).
+
+Each operator has both a terse name (its opname) and a more verbose or
+recognisable descriptive name. The opdesc function can be used to
+return a list of descriptions for a list of operators.
+
+Many of the functions and methods listed below take a list of
+operators as parameters. Most operator lists can be made up of several
+types of element. Each element can be one of
+
+=over 8
+
+=item an operator name (opname)
+
+Operator names are typically small lowercase words like enterloop,
+leaveloop, last, next, redo etc. Sometimes they are rather cryptic
+like gv2cv, i_ncmp and ftsvtx.
+
+=item an operator tag name (optag)
+
+Operator tags can be used to refer to groups (or sets) of operators.
+Tag names always begin with a colon. The Opcode module defines several
+optags and the user can define others using the define_optag function.
+
+=item a negated opname or optag
+
+An opname or optag can be prefixed with an exclamation mark, e.g., !mkdir.
+Negating an opname or optag means remove the corresponding ops from the
+accumulated set of ops at that point.
+
+=item an operator set (opset)
+
+An I<opset> as a binary string of approximately 44 bytes which holds a
+set or zero or more operators.
+
+The opset and opset_to_ops functions can be used to convert from
+a list of operators to an opset and I<vice versa>.
+
+Wherever a list of operators can be given you can use one or more opsets.
+See also Manipulating Opsets below.
+
+=back
+
+
+=head1 Opcode Functions
+
+The Opcode package contains functions for manipulating operator names
+tags and sets. All are available for export by the package.
+
+=over 8
+
+=item opcodes
+
+In a scalar context opcodes returns the number of opcodes in this
+version of perl (around 350 for perl-5.7.0).
+
+In a list context it returns a list of all the operator names.
+(Not yet implemented, use @names = opset_to_ops(full_opset).)
+
+=item opset (OP, ...)
+
+Returns an opset containing the listed operators.
+
+=item opset_to_ops (OPSET)
+
+Returns a list of operator names corresponding to those operators in
+the set.
+
+=item opset_to_hex (OPSET)
+
+Returns a string representation of an opset. Can be handy for debugging.
+
+=item full_opset
+
+Returns an opset which includes all operators.
+
+=item empty_opset
+
+Returns an opset which contains no operators.
+
+=item invert_opset (OPSET)
+
+Returns an opset which is the inverse set of the one supplied.
+
+=item verify_opset (OPSET, ...)
+
+Returns true if the supplied opset looks like a valid opset (is the
+right length etc) otherwise it returns false. If an optional second
+parameter is true then verify_opset will croak on an invalid opset
+instead of returning false.
+
+Most of the other Opcode functions call verify_opset automatically
+and will croak if given an invalid opset.
+
+=item define_optag (OPTAG, OPSET)
+
+Define OPTAG as a symbolic name for OPSET. Optag names always start
+with a colon C<:>.
+
+The optag name used must not be defined already (define_optag will
+croak if it is already defined). Optag names are global to the perl
+process and optag definitions cannot be altered or deleted once
+defined.
+
+It is strongly recommended that applications using Opcode should use a
+leading capital letter on their tag names since lowercase names are
+reserved for use by the Opcode module. If using Opcode within a module
+you should prefix your tags names with the name of your module to
+ensure uniqueness and thus avoid clashes with other modules.
+
+=item opmask_add (OPSET)
+
+Adds the supplied opset to the current opmask. Note that there is
+currently I<no> mechanism for unmasking ops once they have been masked.
+This is intentional.
+
+=item opmask
+
+Returns an opset corresponding to the current opmask.
+
+=item opdesc (OP, ...)
+
+This takes a list of operator names and returns the corresponding list
+of operator descriptions.
+
+=item opdump (PAT)
+
+Dumps to STDOUT a two column list of op names and op descriptions.
+If an optional pattern is given then only lines which match the
+(case insensitive) pattern will be output.
+
+It's designed to be used as a handy command line utility:
+
+ perl -MOpcode=opdump -e opdump
+ perl -MOpcode=opdump -e 'opdump Eval'
+
+=back
+
+=head1 Manipulating Opsets
+
+Opsets may be manipulated using the perl bit vector operators & (and), | (or),
+^ (xor) and ~ (negate/invert).
+
+However you should never rely on the numerical position of any opcode
+within the opset. In other words both sides of a bit vector operator
+should be opsets returned from Opcode functions.
+
+Also, since the number of opcodes in your current version of perl might
+not be an exact multiple of eight, there may be unused bits in the last
+byte of an upset. This should not cause any problems (Opcode functions
+ignore those extra bits) but it does mean that using the ~ operator
+will typically not produce the same 'physical' opset 'string' as the
+invert_opset function.
+
+
+=head1 TO DO (maybe)
+
+ $bool = opset_eq($opset1, $opset2) true if opsets are logically eqiv
+
+ $yes = opset_can($opset, @ops) true if $opset has all @ops set
+
+ @diff = opset_diff($opset1, $opset2) => ('foo', '!bar', ...)
+
+=cut
+
+# the =cut above is used by _init_optags() to get here quickly
+
+=head1 Predefined Opcode Tags
+
+=over 5
+
+=item :base_core
+
+ null stub scalar pushmark wantarray const defined undef
+
+ rv2sv sassign
+
+ rv2av aassign aelem aelemfast aslice av2arylen
+
+ rv2hv helem hslice each values keys exists delete
+
+ preinc i_preinc predec i_predec postinc i_postinc postdec i_postdec
+ int hex oct abs pow multiply i_multiply divide i_divide
+ modulo i_modulo add i_add subtract i_subtract
+
+ left_shift right_shift bit_and bit_xor bit_or negate i_negate
+ not complement
+
+ lt i_lt gt i_gt le i_le ge i_ge eq i_eq ne i_ne ncmp i_ncmp
+ slt sgt sle sge seq sne scmp
+
+ substr vec stringify study pos length index rindex ord chr
+
+ ucfirst lcfirst uc lc quotemeta trans chop schop chomp schomp
+
+ match split qr
+
+ list lslice splice push pop shift unshift reverse
+
+ cond_expr flip flop andassign orassign dorassign and or dor xor
+
+ warn die lineseq nextstate scope enter leave setstate
+
+ rv2cv anoncode prototype
+
+ entersub leavesub leavesublv return method method_named -- XXX loops via recursion?
+
+ leaveeval -- needed for Safe to operate, is safe without entereval
+
+=item :base_mem
+
+These memory related ops are not included in :base_core because they
+can easily be used to implement a resource attack (e.g., consume all
+available memory).
+
+ concat repeat join range
+
+ anonlist anonhash
+
+Note that despite the existence of this optag a memory resource attack
+may still be possible using only :base_core ops.
+
+Disabling these ops is a I<very> heavy handed way to attempt to prevent
+a memory resource attack. It's probable that a specific memory limit
+mechanism will be added to perl in the near future.
+
+=item :base_loop
+
+These loop ops are not included in :base_core because they can easily be
+used to implement a resource attack (e.g., consume all available CPU time).
+
+ grepstart grepwhile
+ mapstart mapwhile
+ enteriter iter
+ enterloop leaveloop unstack
+ last next redo
+ goto
+
+=item :base_io
+
+These ops enable I<filehandle> (rather than filename) based input and
+output. These are safe on the assumption that only pre-existing
+filehandles are available for use. Usually, to create new filehandles
+other ops such as open would need to be enabled, if you don't take into
+account the magical open of ARGV.
+
+ readline rcatline getc read
+
+ formline enterwrite leavewrite
+
+ print say sysread syswrite send recv
+
+ eof tell seek sysseek
+
+ readdir telldir seekdir rewinddir
+
+=item :base_orig
+
+These are a hotchpotch of opcodes still waiting to be considered
+
+ gvsv gv gelem
+
+ padsv padav padhv padany
+
+ once
+
+ rv2gv refgen srefgen ref
+
+ bless -- could be used to change ownership of objects (reblessing)
+
+ pushre regcmaybe regcreset regcomp subst substcont
+
+ sprintf prtf -- can core dump
+
+ crypt
+
+ tie untie
+
+ dbmopen dbmclose
+ sselect select
+ pipe_op sockpair
+
+ getppid getpgrp setpgrp getpriority setpriority localtime gmtime
+
+ entertry leavetry -- can be used to 'hide' fatal errors
+
+ entergiven leavegiven
+ enterwhen leavewhen
+ break continue
+ smartmatch
+
+ custom -- where should this go
+
+=item :base_math
+
+These ops are not included in :base_core because of the risk of them being
+used to generate floating point exceptions (which would have to be caught
+using a $SIG{FPE} handler).
+
+ atan2 sin cos exp log sqrt
+
+These ops are not included in :base_core because they have an effect
+beyond the scope of the compartment.
+
+ rand srand
+
+=item :base_thread
+
+These ops are related to multi-threading.
+
+ lock
+
+=item :default
+
+A handy tag name for a I<reasonable> default set of ops. (The current ops
+allowed are unstable while development continues. It will change.)
+
+ :base_core :base_mem :base_loop :base_orig :base_thread
+
+This list used to contain :base_io prior to Opcode 1.07.
+
+If safety matters to you (and why else would you be using the Opcode module?)
+then you should not rely on the definition of this, or indeed any other, optag!
+
+=item :filesys_read
+
+ stat lstat readlink
+
+ ftatime ftblk ftchr ftctime ftdir fteexec fteowned fteread
+ ftewrite ftfile ftis ftlink ftmtime ftpipe ftrexec ftrowned
+ ftrread ftsgid ftsize ftsock ftsuid fttty ftzero ftrwrite ftsvtx
+
+ fttext ftbinary
+
+ fileno
+
+=item :sys_db
+
+ ghbyname ghbyaddr ghostent shostent ehostent -- hosts
+ gnbyname gnbyaddr gnetent snetent enetent -- networks
+ gpbyname gpbynumber gprotoent sprotoent eprotoent -- protocols
+ gsbyname gsbyport gservent sservent eservent -- services
+
+ gpwnam gpwuid gpwent spwent epwent getlogin -- users
+ ggrnam ggrgid ggrent sgrent egrent -- groups
+
+=item :browse
+
+A handy tag name for a I<reasonable> default set of ops beyond the
+:default optag. Like :default (and indeed all the other optags) its
+current definition is unstable while development continues. It will change.
+
+The :browse tag represents the next step beyond :default. It it a
+superset of the :default ops and adds :filesys_read the :sys_db.
+The intent being that scripts can access more (possibly sensitive)
+information about your system but not be able to change it.
+
+ :default :filesys_read :sys_db
+
+=item :filesys_open
+
+ sysopen open close
+ umask binmode
+
+ open_dir closedir -- other dir ops are in :base_io
+
+=item :filesys_write
+
+ link unlink rename symlink truncate
+
+ mkdir rmdir
+
+ utime chmod chown
+
+ fcntl -- not strictly filesys related, but possibly as dangerous?
+
+=item :subprocess
+
+ backtick system
+
+ fork
+
+ wait waitpid
+
+ glob -- access to Cshell via <`rm *`>
+
+=item :ownprocess
+
+ exec exit kill
+
+ time tms -- could be used for timing attacks (paranoid?)
+
+=item :others
+
+This tag holds groups of assorted specialist opcodes that don't warrant
+having optags defined for them.
+
+SystemV Interprocess Communications:
+
+ msgctl msgget msgrcv msgsnd
+
+ semctl semget semop
+
+ shmctl shmget shmread shmwrite
+
+=item :load
+
+This tag holds opcodes related to loading modules and getting information
+about calling environment and args.
+
+ require dofile
+ caller
+
+=item :still_to_be_decided
+
+ chdir
+ flock ioctl
+
+ socket getpeername ssockopt
+ bind connect listen accept shutdown gsockopt getsockname
+
+ sleep alarm -- changes global timer state and signal handling
+ sort -- assorted problems including core dumps
+ tied -- can be used to access object implementing a tie
+ pack unpack -- can be used to create/use memory pointers
+
+ entereval -- can be used to hide code from initial compile
+
+ reset
+
+ dbstate -- perl -d version of nextstate(ment) opcode
+
+=item :dangerous
+
+This tag is simply a bucket for opcodes that are unlikely to be used via
+a tag name but need to be tagged for completeness and documentation.
+
+ syscall dump chroot
+
+=back
+
+=head1 SEE ALSO
+
+L<ops> -- perl pragma interface to Opcode module.
+
+L<Safe> -- Opcode and namespace limited execution compartments
+
+=head1 AUTHORS
+
+Originally designed and implemented by Malcolm Beattie,
+mbeattie@sable.ox.ac.uk as part of Safe version 1.
+
+Split out from Safe module version 1, named opcode tags and other
+changes added by Tim Bunce.
+
+=cut
+