File: ConfModule.pm

package info (click to toggle)
debconf 1.5.91
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 5,180 kB
  • sloc: perl: 8,500; sh: 262; python: 182; makefile: 144
file content (1042 lines) | stat: -rw-r--r-- 25,568 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
#!/usr/bin/perl

=head1 NAME

Debconf::ConfModule - communicates with a ConfModule

=cut

package Debconf::ConfModule;
use warnings;
use strict;
use IPC::Open2;
use FileHandle;
use Debconf::Gettext;
use Debconf::Config;
use Debconf::Question;
use Debconf::Priority qw(priority_valid high_enough);
use Debconf::FrontEnd::Noninteractive;
use Debconf::Log ':all';
use Debconf::Encoding;
use base qw(Debconf::Base);

=head1 DESCRIPTION

This is a configuration module communication package for the Debian
configuration management system. It can launch a configuration module
script (hereafter called a "confmodule") and communicate with it. Each
instance of a ConfModule is connected to a separate, running confmodule.

There are a number of methods that are called in response to commands
from the client. Each has the same name as the command, with "command_"
prepended, and is fed in the parameters given after the command (split on
whitespace), and whatever it returns is passed back to the configuration
module. Each of them are described below.

=head1 FIELDS

=over 4

=item frontend

The frontend object that is used to interact with the user.

=item version

The protocol version spoken.

=item pid

The PID of the confmodule that is running and talking to this object, if
any.

=item write_handle

Writes to this handle are sent to the confmodule.

=item read_handle

Reads from this handle read from the confmodule.

=item caught_sigpipe

Set if we have caught a SIGPIPE signal. If it is set, the value of the
field should be returned, rather than the normal exit code.

=item client_capb

An array reference. If set, it will hold the capabilities the confmodule
reports.

=item seen

An array reference. If set, it will hold a list of all questions that have
ever been shown to the user in this confmodule run.

=item busy

An array reference. If set, it will hold a list of named of question that are
"busy" -- in the process of being shown, that cannot be unregistered right now.

=back

=head1 METHODS

=over 4

=cut

# Here I define all the numeric result codes that are used.
my %codes = (
	success => 0,
	escaped_data => 1,
	badparams => 10,
	syntaxerror => 20,
	input_invisible => 30,
	version_bad => 30,
	go_back => 30,
	progresscancel => 30,
	internalerror => 100,
);

=item init

Called when a ConfModule is created.

=cut

sub init {
	my $this=shift;

	# Protcol version.
	$this->version("2.0");

	$this->owner('unknown') if ! defined $this->owner;

	# If my frontend thought the client confmodule could backup
	# (eg, because it was dealing earlier with a confmodule that could),
	# tell it otherwise.
	$this->frontend->capb_backup('');

	$this->seen([]);
	$this->busy([]);

	# Let clients know a FrontEnd is actually running.
	$ENV{DEBIAN_HAS_FRONTEND}=1;
}

=item startup

Pass this name name of a confmodule program, and it is started up. Any
further options are parameters to pass to the confmodule. You generally need
to do this before trying to use any of the rest of this object. The
alternative is to launch a confmodule manually, and connect the read_handle
and write_handle fields of this object to it.

=cut

sub startup {
	my $this=shift;
	my $confmodule=shift;

	# There is an implicit clearing of any previously pending questions
	# when a new confmodule is run.
	$this->frontend->clear;
	$this->busy([]);

	my @args=$this->confmodule($confmodule);
	push @args, @_ if @_;

	debug developer => "starting ".join(' ',@args);
	$this->pid(open2($this->read_handle(FileHandle->new),
		         $this->write_handle(FileHandle->new),
			 @args)) || die $!;

	# Catch sigpipes so they don't kill us, and return 128 for them.
	$this->caught_sigpipe('');
	$SIG{PIPE}=sub { $this->caught_sigpipe(128) };
}

=item communicate

Read one command from the confmodule, process it, and respond
to it. Returns true unless there were no more commands to read.
This is typically called in a loop. It in turn calls various
command_* methods.

=cut

sub communicate {
	my $this=shift;

	my $r=$this->read_handle;
	$_=<$r> || return $this->finish;
	chomp;
	my $ret=$this->process_command($_);
	my $w=$this->write_handle;
	print $w $ret."\n";
	return '' unless length $ret;
	return 1;
}

=item escape

Escape backslashes and newlines for output via the debconf protocol.

=cut

sub escape {
	my $text=shift;
	$text=~s/\\/\\\\/g;
	$text=~s/\n/\\n/g;
	return $text;
}

=item unescape_split

Unescape text received via the debconf protocol, and split by unescaped
whitespace.

=cut

sub unescape_split {
	my $text=shift;
	my @words;
	my $word='';
	for my $chunk (split /(\\.|\s+)/, $text) {
		if ($chunk eq '\n') {
			$word.="\n";
		} elsif ($chunk=~/^\\(.)$/) {
			$word.=$1;
		} elsif ($chunk=~/^\s+$/) {
			push @words, $word;
			$word='';
		} else {
			$word.=$chunk;
		}
	}
	push @words, $word if $word ne '';
	return @words;
}

=item process_command

Pass in a raw command, and it will be processed and handled.

=cut

sub process_command {
	my $this=shift;

	debug developer => "<-- $_";
	chomp;
	my ($command, @params);
	if (defined $this->client_capb and grep { $_ eq 'escape' } @{$this->client_capb}) {
		($command, @params)=unescape_split($_);
	} else {
		($command, @params)=split(' ', $_);
	}
	if (! defined $command) {
		my $ret = $codes{syntaxerror}.' '.
			"Bad line \"$_\" received from confmodule.";
		debug developer => "--> $ret";
		return $ret;
	}
	$command=lc($command);
	# This command could not be handled by a sub.
	if (lc($command) eq "stop") {
		return $this->finish;
	}
	# Make sure that the command is valid.
	if (! $this->can("command_$command")) {
		my $ret = $codes{syntaxerror}.' '.
		       "Unsupported command \"$command\" (full line was \"$_\") received from confmodule.";
		debug developer => "--> $ret";
		return $ret;
	}
	# Now call the subroutine for the command.
	$command="command_$command";
	my $ret=join(' ', $this->$command(@params));
	debug developer => "--> $ret";
	if ($ret=~/\n/) {
		debug developer => 'Warning: return value is multiline, and would break the debconf protocol. Truncating to first line.';
		$ret=~s/\n.*//s;
		debug developer => "--> $ret";
	}
	return $ret;
}

=item finish

Waits for the child process (if any) to finish so its return code can be
examined.  The return code is stored in the exitcode field of the object.
It also marks all questions that were shown as seen.

=cut

sub finish {
	my $this=shift;

	waitpid $this->pid, 0 if defined $this->pid;
	$this->exitcode($this->caught_sigpipe || ($? >> 8));

	# Stop catching sigpipe now. IGNORE and DEFAULT both cause obscure
	# failures, BTW.
	$SIG{PIPE} = sub {};

	foreach (@{$this->seen}) {
		# Try to get the question again, because it's possible it
		# was shown, and then unregistered.
		my $q=Debconf::Question->get($_->name);
		$_->flag('seen', 'true') if $q;
	}
	$this->seen([]);

	return '';
}

=item command_input

Creates an Element to stand for the question that is to be asked and adds it to
the list of elements in our associated FrontEnd.

=cut

sub command_input {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 2;
	my $priority=shift;
	my $question_name=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "\"$question_name\" doesn't exist";

	if (! priority_valid($priority)) {
		return $codes{syntaxerror}, "\"$priority\" is not a valid priority";
	}

	$question->priority($priority);

	# Figure out if the question should be displayed to the user or
	# not.
	my $visible=1;

	# Error questions are always shown even if they're asked at a low
	# priority or have already been seen.
	if ($question->type ne 'error') {
		# Don't show items that are unimportant.
		$visible='' unless high_enough($priority);

		# Don't re-show already seen questions, unless reconfiguring.
		$visible='' if ! Debconf::Config->reshow &&
			       $question->flag('seen') eq 'true';
	}

	# We may want to set the seen flag on noninteractive questions
	# even though they aren't shown.
	my $markseen=$visible;

	# Noninteractive frontends never show anything.
	if ($visible && ! $this->frontend->interactive) {
		$visible='';
		$markseen='' unless Debconf::Config->noninteractive_seen eq 'true';
	}

	my $element;
	if ($visible) {
		# Create an input Element of the type associated with
		# the frontend.
		$element=$this->frontend->makeelement($question);
		# If that failed, quit now. This should never happen.
		unless ($element) {
			return $codes{internalerror},
			       "unable to make an input element";
		}

		# Ask the Element if it thinks it is visible. If not,
		# fall back below to making a noninteractive element.
		#
		# This last check is useful, because for example, select
		# Elements are not really visible if they have less than
		# two choices.
		$visible=$element->visible;
	}

	if (! $visible) {
		# Create a noninteractive element. Supress debug messages
		# because they generate FAQ's and are harmless.
		$element=Debconf::FrontEnd::Noninteractive->makeelement($question, 1);

		# If that failed, the question is just not visible.
		return $codes{input_invisible}, "question skipped" unless $element;
	}

	$element->markseen($markseen);

	push @{$this->busy}, $question_name;

	$this->frontend->add($element);
	if ($element->visible) {
		return $codes{success}, "question will be asked";
	}
	else {
		return $codes{input_invisible}, "question skipped";
	}
}

=item command_clear

Clears out the list of elements in our accociated FrontEnd.

=cut

sub command_clear {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 0;

	$this->frontend->clear;
	$this->busy([]);
	return $codes{success};
}

=item command_version

Compares protocol versions with the confmodule. The version field of the
ConfModule is sent to the client.

=cut

sub command_version {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ > 1;
	my $version=shift;
	if (defined $version) {
		return $codes{version_bad}, "Version too low ($version)"
			if int($version) < int($this->version);
		return $codes{version_bad}, "Version too high ($version)"
			if int($version) > int($this->version);
	}
	return $codes{success}, $this->version;
}

=item command_capb

Sets the client_capb field to the confmodules's capabilities, and also
sets the capb_backup field of the ConfModules associated FrontEnd if
the confmodule can backup. Sends the capb field of the associated
FrontEnd to the confmodule.

=cut

sub command_capb {
	my $this=shift;
	$this->client_capb([@_]);
	# Set capb_backup on the frontend if the client can backup.
	if (grep { $_ eq 'backup' } @_) {
		$this->frontend->capb_backup(1);
	} else {
		$this->frontend->capb_backup('');
	}
	# Multiselect is added as a capability to fix a backwards
	# compatability problem.
	my @capb=('multiselect', 'escape');
	push @capb, $this->frontend->capb;
	return $codes{success}, @capb;
}

=item command_title

Stores the specified title in the associated FrontEnds title field.

=cut

sub command_title {
	my $this=shift;
	$this->frontend->title(join ' ', @_);
	$this->frontend->requested_title($this->frontend->title);

	return $codes{success};
}

=item command_settitle

Uses the short description of a question as the title, with automatic i18n.

=cut

sub command_settitle {
	my $this=shift;

	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
	my $question_name=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "\"$question_name\" doesn't exist";

	if ($this->frontend->can('settitle')) {
		$this->frontend->settitle($question);
	} else {
		$this->frontend->title($question->description);
	}
	$this->frontend->requested_title($this->frontend->title);

	return $codes{success};
}

=item beginblock, endblock

These are just stubs to be overridden by other modules.

=cut

sub command_beginblock {
	return $codes{success};
}
sub command_endblock {
	return $codes{success};
}

=item command_go

Tells the associated FrontEnd to display items to the user, by calling
its go method. That method should return false if the user asked to back
up, and true otherwise. If it returns true, then all of the questions that
were displayed are added to the seen array.

=cut

sub command_go {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ > 0;

	my $ret=$this->frontend->go;
	# If no elements were shown, and we backed up last time, back up again
	# even if the user didn't indicate they want to back up. This
	# causes invisible elements to be skipped over in multi-stage backups.
	if ($ret && (! $this->backed_up ||
	             grep { $_->visible } @{$this->frontend->elements})) {
		foreach (@{$this->frontend->elements}) {
			$_->question->value($_->value);
			push @{$this->seen}, $_->question if $_->markseen && $_->question;
		}
		$this->frontend->clear;
		$this->busy([]);
		$this->backed_up('');
		return $codes{success}, "ok"
	}
	else {
		$this->frontend->clear;
		$this->busy([]);
		$this->backed_up(1);
		return $codes{go_back}, "backup";
	}
}

=item command_get

This must be passed a question name. It queries the question for the value
set in it and returns that to the confmodule

=cut

sub command_get {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
	my $question_name=shift;
	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";

	my $value=$question->value;
	if (defined $value) {
		if (defined $this->client_capb and grep { $_ eq 'escape' } @{$this->client_capb}) {
			return $codes{escaped_data}, escape($value);
		} else {
			return $codes{success}, $value;
		}
	}
	else {
		return $codes{success}, '';
	}
}

=item command_set

This must be passed a question name and a value. It sets the question's value.

=cut

sub command_set {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 1;
	my $question_name=shift;
	my $value=join(" ", @_);

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";
	$question->value($value);
	return $codes{success}, "value set";
}

=item command_reset

Reset a question to its default value.

=cut

sub command_reset {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
	my $question_name=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";
	$question->value($question->default);
	$question->flag('seen', 'false');
	return $codes{success};
}

=item command_subst

This must be passed a question name, a key, and a value. It sets up variable
substitutions on the questions description so all instances of the key
(wrapped in "${}") are replaced with the value.

=cut

sub command_subst {
	my $this = shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 2;
	my $question_name = shift;
	my $variable = shift;
	my $value = (join ' ', @_);

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";
	my $result=$question->variable($variable,$value);
	return $codes{internalerror}, "Substitution failed" unless defined $result;
	return $codes{success};
}

=item command_register

This should be passed a template name and a question name. Registers a
question to use the template.

=cut

sub command_register {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 2;
	my $template=shift;
	my $name=shift;

	my $tempobj = Debconf::Question->get($template);
	if (! $tempobj) {
		return $codes{badparams}, "No such template, \"$template\"";
	}
	my $question=Debconf::Question->get($name) ||
	             Debconf::Question->new($name, $this->owner, $tempobj->type);
	if (! $question) {
		return $codes{internalerror}, "Internal error making question";
	}
	if (! defined $question->addowner($this->owner, $tempobj->type)) {
		return $codes{internalerror}, "Internal error adding owner";
	}
	if (! $question->template($template)) {
		return $codes{internalerror}, "Internal error setting template";
	}

	return $codes{success};
}

=item command_unregister

Pass this a question name, and it will give up ownership of the question,
which typically causes it to be removed.

=cut

sub command_unregister {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
	my $name=shift;

	my $question=Debconf::Question->get($name) ||
		return $codes{badparams}, "$name doesn't exist";
	if (grep { $_ eq $name } @{$this->busy}) {
		return $codes{badparams}, "$name is busy, cannot unregister right now";
	}
	$question->removeowner($this->owner);
	return $codes{success};
}

=item command_purge

This will give up ownership of all questions a confmodule owns.

=cut

sub command_purge {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ > 0;

	my $iterator=Debconf::Question->iterator;
	while (my $q=$iterator->iterate) {
		$q->removeowner($this->owner);
	}

	return $codes{success};
}

=item command_metaget

Pass this a question name and a field name. It returns the value of the
specified field of the question.

=cut

sub command_metaget {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 2;
	my $question_name=shift;
	my $field=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";
	my $lcfield=lc $field;
	my $fieldval=$question->$lcfield();
	unless (defined $fieldval) {
		return $codes{badparams}, "$field does not exist";
	}
	if (defined $this->client_capb and grep { $_ eq 'escape' } @{$this->client_capb}) {
		return $codes{escaped_data}, escape($fieldval);
	} else {
		return $codes{success}, $fieldval;
	}
}

=item command_fget

Pass this a question name and a flag name. It returns the value of the
specified flag on the question.

=cut

sub command_fget {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 2;
	my $question_name=shift;
	my $flag=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams},  "$question_name doesn't exist";

	return $codes{success}, $question->flag($flag);
}

=item command_fset

Pass this a question name, a flag name, and a value. It sets the value of
the specified flag in the specified question.

=cut

sub command_fset {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 3;
	my $question_name=shift;
	my $flag=shift;
	my $value=(join ' ', @_);

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";

	if ($flag eq 'seen') {
		# If this question we're being asked to modify is one that was
		# shown in the current session, it will be in our seen
		# cache, and changing its value here will not persist
		# after this session, because the seen property overwrites
		# the values at the end of the session. Therefore, remove
		# it from our seen cache.
		$this->seen([grep {$_ ne $question} @{$this->seen}]);
	}

	return $codes{success}, $question->flag($flag, $value);
}

=item command_info

Pass this a question name. It displays the given template as an out-of-band
informative message. Unlike inputting a note, this doesn't require an
acknowledgement from the user, and depending on the frontend it may not even
be displayed at all. Frontends should display the info persistently until
some other info comes along.

With no arguments, this resets the info message to a default value.

=cut

sub command_info {
	my $this=shift;

	if (@_ == 0) {
		$this->frontend->info(undef);
	} elsif (@_ == 1) {
		my $question_name=shift;

		my $question=Debconf::Question->get($question_name) ||
			return $codes{badparams}, "\"$question_name\" doesn't exist";

		$this->frontend->info($question);
	} else {
		return $codes{syntaxerror}, "Incorrect number of arguments";
	}

	return $codes{success};
}

=item command_progress

Progress bar handling. Pass this a subcommand name followed by any arguments
required by the subcommand, as follows:

=over 4

=item START

Pass this a minimum value, a maximum value, and a question name. It creates
a progress bar with the specified range and the description of the specified
question as the title.

=item SET

Pass this a value. It sets the current position of the progress bar to the
specified value.

=item STEP

Pass this an increment. It increments the current position of the progress
bar by the specified amount.

=item INFO

Pass this a template name. It displays the specified template as an
informational message in the progress bar.

=item STOP

This subcommand takes no arguments. It destroys the progress bar.

=back

Note that the frontend's progress_set, progress_step, and progress_info
functions should return true, unless the progress bar was canceled.

=cut

sub command_progress {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 1;
	my $subcommand=shift;
	$subcommand=lc($subcommand);

	my $ret;

	if ($subcommand eq 'start') {
		return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 3;
		my $min=shift;
		my $max=shift;
		my $question_name=shift;

		return $codes{syntaxerror}, "min ($min) > max ($max)" if $min > $max;

		my $question=Debconf::Question->get($question_name) ||
			return $codes{badparams}, "$question_name doesn't exist";

		$this->frontend->progress_start($min, $max, $question);
		$ret=1;
	}
	elsif ($subcommand eq 'set') {
		return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
		my $value=shift;
		$ret = $this->frontend->progress_set($value);
	}
	elsif ($subcommand eq 'step') {
		return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
		my $inc=shift;
		$ret = $this->frontend->progress_step($inc);
	}
	elsif ($subcommand eq 'info') {
		return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
		my $question_name=shift;

		my $question=Debconf::Question->get($question_name) ||
			return $codes{badparams}, "$question_name doesn't exist";

		$ret = $this->frontend->progress_info($question);
	}
	elsif ($subcommand eq 'stop') {
		return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 0;
		$this->frontend->progress_stop();
		$ret=1;
	}
	else {
		return $codes{syntaxerror}, "Unknown subcommand";
	}

	if ($ret) {
		return $codes{success}, "OK";
	}
	else {
		return $codes{progresscancel}, "CANCELED";
	}
}

=item command_data

Accept template data from the client, for use on the UI agent side of the
passthrough frontend.

TODO: Since process_command() collapses multiple spaces in commands into
single spaces, this doesn't quite handle bulleted lists correctly.

=cut

sub command_data {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 3;
	my $template=shift;
	my $item=shift;
	my $value=join(' ', @_);
	$value=~s/\\([n"\\])/($1 eq 'n') ? "\n" : $1/eg;

	my $tempobj=Debconf::Template->get($template);
	if (! $tempobj) {
		if ($item ne 'type') {
			return $codes{badparams}, "Template data field '$item' received before type field";
		}
		$tempobj=Debconf::Template->new($template, $this->owner, $value);
		if (! $tempobj) {
			return $codes{internalerror}, "Internal error making template";
		}
	} else {
		if ($item eq 'type') {
			return $codes{badparams}, "Template type already set";
		}
		$tempobj->$item(Debconf::Encoding::convert("UTF-8", $value));
	}

	return $codes{success};
}

=item command_visible

Deprecated.

=cut

sub command_visible {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 2;
	my $priority=shift;
	my $question_name=shift;

	my $question=Debconf::Question->get($question_name) ||
		return $codes{badparams}, "$question_name doesn't exist";
	return $codes{success}, $this->frontend->visible($question, $priority) ? "true" : "false";
}

=item command_exist

Deprecated.

=cut

sub command_exist {
	my $this=shift;
	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ != 1;
	my $question_name=shift;

	return $codes{success},
		Debconf::Question->get($question_name) ? "true" : "false";
}

=item command_x_loadtemplatefile

Extension to load a specified template file.

=cut

sub command_x_loadtemplatefile {
	my $this=shift;

	return $codes{syntaxerror}, "Incorrect number of arguments" if @_ < 1 || @_ > 2;

	my $file=shift;
	my $fh=FileHandle->new($file);
	if (! $fh) {
		return $codes{badparams}, "failed to open $file: $!";
	}

	my $owner=$this->owner;
	if (@_) {
		$owner=shift;
	}

	eval {
		Debconf::Template->load($fh, $owner);
	};
	if ($@) {
		$@=~s/\n/\\n/g;
		return $codes{internalerror}, $@;
	}
	return $codes{success};
}

=item AUTOLOAD

Handles storing and loading fields.

=cut

sub AUTOLOAD {
	(my $field = our $AUTOLOAD) =~ s/.*://;

	no strict 'refs';
	*$AUTOLOAD = sub {
		my $this=shift;

		return $this->{$field} unless @_;
		return $this->{$field}=shift;
	};
	goto &$AUTOLOAD;
}

=item DESTROY

When the object is destroyed, the filehandles are closed and the confmodule
script stopped. All questions that have been displayed during the lifetime
of the confmodule are marked as seen.

=cut

sub DESTROY {
	my $this=shift;

	$this->read_handle->close if $this->read_handle;
	$this->write_handle->close if $this->write_handle;

	if (defined $this->pid && $this->pid > 1) {
		kill 'TERM', $this->pid;
	}
}

=back

=head1 AUTHOR

Joey Hess <joeyh@debian.org>

=cut

1