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Add string- and number-specific bitop types
[perl5.git] / ext / Opcode / Opcode.pm
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1package Opcode;
2
3b825e41 3use 5.006_001;
6badd1a5 4
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5use strict;
6
4eb3f1b8 7our($VERSION, @ISA, @EXPORT_OK);
6badd1a5 8
00fdeebd 9$VERSION = "1.32";
6badd1a5 10
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11use Carp;
12use Exporter ();
da4061d3 13use XSLoader;
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14
15BEGIN {
b75c8c73 16 @ISA = qw(Exporter);
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17 @EXPORT_OK = qw(
18 opset ops_to_opset
19 opset_to_ops opset_to_hex invert_opset
20 empty_opset full_opset
21 opdesc opcodes opmask define_optag
22 opmask_add verify_opset opdump
23 );
24}
25
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26sub opset (;@);
27sub opset_to_hex ($);
28sub opdump (;$);
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29use subs @EXPORT_OK;
30
da4061d3 31XSLoader::load();
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32
33_init_optags();
34
68dc0745 35sub ops_to_opset { opset @_ } # alias for old name
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36
37sub opset_to_hex ($) {
38 return "(invalid opset)" unless verify_opset($_[0]);
39 unpack("h*",$_[0]);
40}
41
42sub opdump (;$) {
43 my $pat = shift;
44 # handy utility: perl -MOpcode=opdump -e 'opdump File'
45 foreach(opset_to_ops(full_opset)) {
46 my $op = sprintf " %12s %s\n", $_, opdesc($_);
47 next if defined $pat and $op !~ m/$pat/i;
48 print $op;
49 }
50}
51
52
53
54sub _init_optags {
55 my(%all, %seen);
56 @all{opset_to_ops(full_opset)} = (); # keys only
57
7a57407b 58 local($_);
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59 local($/) = "\n=cut"; # skip to optags definition section
60 <DATA>;
61 $/ = "\n="; # now read in 'pod section' chunks
62 while(<DATA>) {
63 next unless m/^item\s+(:\w+)/;
64 my $tag = $1;
65
66 # Split into lines, keep only indented lines
67 my @lines = grep { m/^\s/ } split(/\n/);
be1d34d7 68 foreach (@lines) { s/(?:\t|--).*// } # delete comments
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69 my @ops = map { split ' ' } @lines; # get op words
70
71 foreach(@ops) {
72 warn "$tag - $_ already tagged in $seen{$_}\n" if $seen{$_};
73 $seen{$_} = $tag;
74 delete $all{$_};
75 }
76 # opset will croak on invalid names
77 define_optag($tag, opset(@ops));
78 }
79 close(DATA);
80 warn "Untagged opnames: ".join(' ',keys %all)."\n" if %all;
81}
82
83
841;
85
86__DATA__
87
88=head1 NAME
89
90Opcode - Disable named opcodes when compiling perl code
91
92=head1 SYNOPSIS
93
94 use Opcode;
95
96
97=head1 DESCRIPTION
98
99Perl code is always compiled into an internal format before execution.
100
101Evaluating perl code (e.g. via "eval" or "do 'file'") causes
102the code to be compiled into an internal format and then,
103provided there was no error in the compilation, executed.
104The internal format is based on many distinct I<opcodes>.
105
106By default no opmask is in effect and any code can be compiled.
107
108The Opcode module allow you to define an I<operator mask> to be in
109effect when perl I<next> compiles any code. Attempting to compile code
110which contains a masked opcode will cause the compilation to fail
111with an error. The code will not be executed.
112
113=head1 NOTE
114
115The Opcode module is not usually used directly. See the ops pragma and
116Safe modules for more typical uses.
117
118=head1 WARNING
119
120The authors make B<no warranty>, implied or otherwise, about the
121suitability of this software for safety or security purposes.
122
123The authors shall not in any case be liable for special, incidental,
124consequential, indirect or other similar damages arising from the use
125of this software.
126
127Your mileage will vary. If in any doubt B<do not use it>.
128
129
130=head1 Operator Names and Operator Lists
131
132The canonical list of operator names is the contents of the array
4369b173 133PL_op_name defined and initialised in file F<opcode.h> of the Perl
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134source distribution (and installed into the perl library).
135
136Each operator has both a terse name (its opname) and a more verbose or
137recognisable descriptive name. The opdesc function can be used to
138return a list of descriptions for a list of operators.
139
140Many of the functions and methods listed below take a list of
141operators as parameters. Most operator lists can be made up of several
142types of element. Each element can be one of
143
144=over 8
145
146=item an operator name (opname)
147
148Operator names are typically small lowercase words like enterloop,
149leaveloop, last, next, redo etc. Sometimes they are rather cryptic
150like gv2cv, i_ncmp and ftsvtx.
151
152=item an operator tag name (optag)
153
154Operator tags can be used to refer to groups (or sets) of operators.
7b8d334a 155Tag names always begin with a colon. The Opcode module defines several
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156optags and the user can define others using the define_optag function.
157
158=item a negated opname or optag
159
160An opname or optag can be prefixed with an exclamation mark, e.g., !mkdir.
161Negating an opname or optag means remove the corresponding ops from the
162accumulated set of ops at that point.
163
164=item an operator set (opset)
165
7c011d3a 166An I<opset> as a binary string of approximately 44 bytes which holds a
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167set or zero or more operators.
168
169The opset and opset_to_ops functions can be used to convert from
170a list of operators to an opset and I<vice versa>.
171
172Wherever a list of operators can be given you can use one or more opsets.
173See also Manipulating Opsets below.
174
175=back
176
177
178=head1 Opcode Functions
179
180The Opcode package contains functions for manipulating operator names
181tags and sets. All are available for export by the package.
182
183=over 8
184
185=item opcodes
186
187In a scalar context opcodes returns the number of opcodes in this
7c011d3a 188version of perl (around 350 for perl-5.7.0).
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189
190In a list context it returns a list of all the operator names.
191(Not yet implemented, use @names = opset_to_ops(full_opset).)
192
193=item opset (OP, ...)
194
195Returns an opset containing the listed operators.
196
197=item opset_to_ops (OPSET)
198
199Returns a list of operator names corresponding to those operators in
200the set.
201
202=item opset_to_hex (OPSET)
203
204Returns a string representation of an opset. Can be handy for debugging.
205
206=item full_opset
207
208Returns an opset which includes all operators.
209
210=item empty_opset
211
212Returns an opset which contains no operators.
213
214=item invert_opset (OPSET)
215
216Returns an opset which is the inverse set of the one supplied.
217
218=item verify_opset (OPSET, ...)
219
220Returns true if the supplied opset looks like a valid opset (is the
221right length etc) otherwise it returns false. If an optional second
222parameter is true then verify_opset will croak on an invalid opset
223instead of returning false.
224
225Most of the other Opcode functions call verify_opset automatically
226and will croak if given an invalid opset.
227
228=item define_optag (OPTAG, OPSET)
229
230Define OPTAG as a symbolic name for OPSET. Optag names always start
231with a colon C<:>.
232
233The optag name used must not be defined already (define_optag will
234croak if it is already defined). Optag names are global to the perl
235process and optag definitions cannot be altered or deleted once
236defined.
237
238It is strongly recommended that applications using Opcode should use a
239leading capital letter on their tag names since lowercase names are
240reserved for use by the Opcode module. If using Opcode within a module
241you should prefix your tags names with the name of your module to
242ensure uniqueness and thus avoid clashes with other modules.
243
244=item opmask_add (OPSET)
245
246Adds the supplied opset to the current opmask. Note that there is
247currently I<no> mechanism for unmasking ops once they have been masked.
248This is intentional.
249
250=item opmask
251
252Returns an opset corresponding to the current opmask.
253
254=item opdesc (OP, ...)
255
256This takes a list of operator names and returns the corresponding list
257of operator descriptions.
258
259=item opdump (PAT)
260
261Dumps to STDOUT a two column list of op names and op descriptions.
262If an optional pattern is given then only lines which match the
263(case insensitive) pattern will be output.
264
265It's designed to be used as a handy command line utility:
266
267 perl -MOpcode=opdump -e opdump
268 perl -MOpcode=opdump -e 'opdump Eval'
269
270=back
271
272=head1 Manipulating Opsets
273
274Opsets may be manipulated using the perl bit vector operators & (and), | (or),
275^ (xor) and ~ (negate/invert).
276
277However you should never rely on the numerical position of any opcode
278within the opset. In other words both sides of a bit vector operator
279should be opsets returned from Opcode functions.
280
281Also, since the number of opcodes in your current version of perl might
282not be an exact multiple of eight, there may be unused bits in the last
283byte of an upset. This should not cause any problems (Opcode functions
284ignore those extra bits) but it does mean that using the ~ operator
285will typically not produce the same 'physical' opset 'string' as the
286invert_opset function.
287
288
289=head1 TO DO (maybe)
290
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291 $bool = opset_eq($opset1, $opset2) true if opsets are logically
292 equivalent
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293 $yes = opset_can($opset, @ops) true if $opset has all @ops set
294
295 @diff = opset_diff($opset1, $opset2) => ('foo', '!bar', ...)
296
297=cut
298
299# the =cut above is used by _init_optags() to get here quickly
300
301=head1 Predefined Opcode Tags
302
303=over 5
304
305=item :base_core
306
307 null stub scalar pushmark wantarray const defined undef
308
309 rv2sv sassign
310
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311 rv2av aassign aelem aelemfast aelemfast_lex aslice kvaslice
312 av2arylen
6badd1a5 313
92b4bdf2 314 rv2hv helem hslice kvhslice each values keys exists delete
fedf30e1 315 aeach akeys avalues reach rvalues rkeys multideref
6badd1a5 316
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317 preinc i_preinc predec i_predec postinc i_postinc
318 postdec i_postdec int hex oct abs pow multiply i_multiply
319 divide i_divide modulo i_modulo add i_add subtract i_subtract
6badd1a5 320
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321 left_shift right_shift bit_and bit_xor bit_or nbit_and
322 nbit_xor nbit_or sbit_and sbit_xor sbit_or negate i_negate not
323 complement ncomplement scomplement
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324
325 lt i_lt gt i_gt le i_le ge i_ge eq i_eq ne i_ne ncmp i_ncmp
326 slt sgt sle sge seq sne scmp
327
328 substr vec stringify study pos length index rindex ord chr
329
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330 ucfirst lcfirst uc lc fc quotemeta trans transr chop schop
331 chomp schomp
6badd1a5 332
8782bef2 333 match split qr
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334
335 list lslice splice push pop shift unshift reverse
336
c963b151 337 cond_expr flip flop andassign orassign dorassign and or dor xor
6badd1a5 338
5edb5b2a 339 warn die lineseq nextstate scope enter leave
6badd1a5 340
b77472f9 341 rv2cv anoncode prototype coreargs anonconst
6badd1a5 342
1b355718 343 entersub leavesub leavesublv return method method_named
810bd8b7 344 method_super method_redir method_redir_super
be1d34d7 345 -- XXX loops via recursion?
6badd1a5 346
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347 leaveeval -- needed for Safe to operate, is safe
348 without entereval
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349
350=item :base_mem
351
352These memory related ops are not included in :base_core because they
353can easily be used to implement a resource attack (e.g., consume all
354available memory).
355
356 concat repeat join range
357
358 anonlist anonhash
359
3c4b39be 360Note that despite the existence of this optag a memory resource attack
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361may still be possible using only :base_core ops.
362
363Disabling these ops is a I<very> heavy handed way to attempt to prevent
364a memory resource attack. It's probable that a specific memory limit
365mechanism will be added to perl in the near future.
366
367=item :base_loop
368
369These loop ops are not included in :base_core because they can easily be
370used to implement a resource attack (e.g., consume all available CPU time).
371
372 grepstart grepwhile
373 mapstart mapwhile
374 enteriter iter
e897d888 375 enterloop leaveloop unstack
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376 last next redo
377 goto
378
379=item :base_io
380
381These ops enable I<filehandle> (rather than filename) based input and
382output. These are safe on the assumption that only pre-existing
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383filehandles are available for use. Usually, to create new filehandles
384other ops such as open would need to be enabled, if you don't take into
385account the magical open of ARGV.
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386
387 readline rcatline getc read
388
389 formline enterwrite leavewrite
390
0d863452 391 print say sysread syswrite send recv
96e4d5b1 392
8903cb82 393 eof tell seek sysseek
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394
395 readdir telldir seekdir rewinddir
396
397=item :base_orig
398
399These are a hotchpotch of opcodes still waiting to be considered
400
401 gvsv gv gelem
402
a7fd8ef6 403 padsv padav padhv padcv padany padrange introcv clonecv
6badd1a5 404
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405 once
406
2882b3ff 407 rv2gv refgen srefgen ref refassign lvref lvrefslice lvavref
6badd1a5 408
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409 bless -- could be used to change ownership of objects
410 (reblessing)
6badd1a5 411
2cd61cdb 412 pushre regcmaybe regcreset regcomp subst substcont
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413
414 sprintf prtf -- can core dump
415
416 crypt
417
418 tie untie
419
420 dbmopen dbmclose
421 sselect select
422 pipe_op sockpair
423
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424 getppid getpgrp setpgrp getpriority setpriority
425 localtime gmtime
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426
427 entertry leavetry -- can be used to 'hide' fatal errors
428
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429 entergiven leavegiven
430 enterwhen leavewhen
431 break continue
432 smartmatch
433
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434 custom -- where should this go
435
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436=item :base_math
437
438These ops are not included in :base_core because of the risk of them being
439used to generate floating point exceptions (which would have to be caught
440using a $SIG{FPE} handler).
441
442 atan2 sin cos exp log sqrt
443
444These ops are not included in :base_core because they have an effect
445beyond the scope of the compartment.
446
447 rand srand
448
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449=item :base_thread
450
554b3eca 451These ops are related to multi-threading.
1f5895a1 452
5b9081af 453 lock
1f5895a1 454
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455=item :default
456
457A handy tag name for a I<reasonable> default set of ops. (The current ops
458allowed are unstable while development continues. It will change.)
459
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460 :base_core :base_mem :base_loop :base_orig :base_thread
461
462This list used to contain :base_io prior to Opcode 1.07.
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463
464If safety matters to you (and why else would you be using the Opcode module?)
465then you should not rely on the definition of this, or indeed any other, optag!
466
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467=item :filesys_read
468
469 stat lstat readlink
470
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471 ftatime ftblk ftchr ftctime ftdir fteexec fteowned
472 fteread ftewrite ftfile ftis ftlink ftmtime ftpipe
473 ftrexec ftrowned ftrread ftsgid ftsize ftsock ftsuid
474 fttty ftzero ftrwrite ftsvtx
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475
476 fttext ftbinary
477
478 fileno
479
480=item :sys_db
481
482 ghbyname ghbyaddr ghostent shostent ehostent -- hosts
483 gnbyname gnbyaddr gnetent snetent enetent -- networks
484 gpbyname gpbynumber gprotoent sprotoent eprotoent -- protocols
485 gsbyname gsbyport gservent sservent eservent -- services
486
487 gpwnam gpwuid gpwent spwent epwent getlogin -- users
488 ggrnam ggrgid ggrent sgrent egrent -- groups
489
490=item :browse
491
492A handy tag name for a I<reasonable> default set of ops beyond the
493:default optag. Like :default (and indeed all the other optags) its
494current definition is unstable while development continues. It will change.
495
496The :browse tag represents the next step beyond :default. It it a
497superset of the :default ops and adds :filesys_read the :sys_db.
498The intent being that scripts can access more (possibly sensitive)
499information about your system but not be able to change it.
500
501 :default :filesys_read :sys_db
502
503=item :filesys_open
504
505 sysopen open close
506 umask binmode
507
508 open_dir closedir -- other dir ops are in :base_io
509
510=item :filesys_write
511
512 link unlink rename symlink truncate
513
514 mkdir rmdir
515
516 utime chmod chown
517
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518 fcntl -- not strictly filesys related, but possibly as
519 dangerous?
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520
521=item :subprocess
522
523 backtick system
524
525 fork
526
527 wait waitpid
528
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529 glob -- access to Cshell via <`rm *`>
530
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531=item :ownprocess
532
533 exec exit kill
534
535 time tms -- could be used for timing attacks (paranoid?)
536
537=item :others
538
539This tag holds groups of assorted specialist opcodes that don't warrant
540having optags defined for them.
541
542SystemV Interprocess Communications:
543
544 msgctl msgget msgrcv msgsnd
545
546 semctl semget semop
547
548 shmctl shmget shmread shmwrite
549
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550=item :load
551
552This tag holds opcodes related to loading modules and getting information
553about calling environment and args.
554
555 require dofile
84ed0108 556 caller runcv
6e8b06a8 557
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558=item :still_to_be_decided
559
560 chdir
561 flock ioctl
562
563 socket getpeername ssockopt
564 bind connect listen accept shutdown gsockopt getsockname
565
566 sleep alarm -- changes global timer state and signal handling
567 sort -- assorted problems including core dumps
568 tied -- can be used to access object implementing a tie
569 pack unpack -- can be used to create/use memory pointers
570
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571 hintseval -- constant op holding eval hints
572
6badd1a5 573 entereval -- can be used to hide code from initial compile
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574
575 reset
576
577 dbstate -- perl -d version of nextstate(ment) opcode
578
579=item :dangerous
580
581This tag is simply a bucket for opcodes that are unlikely to be used via
3c4b39be 582a tag name but need to be tagged for completeness and documentation.
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583
584 syscall dump chroot
585
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586=back
587
588=head1 SEE ALSO
589
86780939 590L<ops> -- perl pragma interface to Opcode module.
6badd1a5 591
86780939 592L<Safe> -- Opcode and namespace limited execution compartments
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593
594=head1 AUTHORS
595
596Originally designed and implemented by Malcolm Beattie,
597mbeattie@sable.ox.ac.uk as part of Safe version 1.
598
599Split out from Safe module version 1, named opcode tags and other
7b8d334a 600changes added by Tim Bunce.
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601
602=cut
603