This file is indexed.

/usr/share/perl/5.20.2/Carp.pm is in perl-base 5.20.2-3+deb8u11.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
package Carp;

{ use 5.006; }
use strict;
use warnings;
BEGIN {
    # Very old versions of warnings.pm load Carp.  This can go wrong due
    # to the circular dependency.  If warnings is invoked before Carp,
    # then warnings starts by loading Carp, then Carp (above) tries to
    # invoke warnings, and gets nothing because warnings is in the process
    # of loading and hasn't defined its import method yet.  If we were
    # only turning on warnings ("use warnings" above) this wouldn't be too
    # bad, because Carp would just gets the state of the -w switch and so
    # might not get some warnings that it wanted.  The real problem is
    # that we then want to turn off Unicode warnings, but "no warnings
    # 'utf8'" won't be effective if we're in this circular-dependency
    # situation.  So, if warnings.pm is an affected version, we turn
    # off all warnings ourselves by directly setting ${^WARNING_BITS}.
    # On unaffected versions, we turn off just Unicode warnings, via
    # the proper API.
    if(!defined($warnings::VERSION) || eval($warnings::VERSION) < 1.06) {
	${^WARNING_BITS} = "";
    } else {
	"warnings"->unimport("utf8");
    }
}

sub _fetch_sub { # fetch sub without autovivifying
    my($pack, $sub) = @_;
    $pack .= '::';
    # only works with top-level packages
    return unless exists($::{$pack});
    for ($::{$pack}) {
	return unless ref \$_ eq 'GLOB' && *$_{HASH} && exists $$_{$sub};
	for ($$_{$sub}) {
	    return ref \$_ eq 'GLOB' ? *$_{CODE} : undef
	}
    }
}

# UTF8_REGEXP_PROBLEM is a compile-time constant indicating whether Carp
# must avoid applying a regular expression to an upgraded (is_utf8)
# string.  There are multiple problems, on different Perl versions,
# that require this to be avoided.  All versions prior to 5.13.8 will
# load utf8_heavy.pl for the swash system, even if the regexp doesn't
# use character classes.  Perl 5.6 and Perls [5.11.2, 5.13.11) exhibit
# specific problems when Carp is being invoked in the aftermath of a
# syntax error.
BEGIN {
    if("$]" < 5.013011) {
	*UTF8_REGEXP_PROBLEM = sub () { 1 };
    } else {
	*UTF8_REGEXP_PROBLEM = sub () { 0 };
    }
}

# is_utf8() is essentially the utf8::is_utf8() function, which indicates
# whether a string is represented in the upgraded form (using UTF-8
# internally).  As utf8::is_utf8() is only available from Perl 5.8
# onwards, extra effort is required here to make it work on Perl 5.6.
BEGIN {
    if(defined(my $sub = _fetch_sub utf8 => 'is_utf8')) {
	*is_utf8 = $sub;
    } else {
	# black magic for perl 5.6
	*is_utf8 = sub { unpack("C", "\xaa".$_[0]) != 170 };
    }
}

# The downgrade() function defined here is to be used for attempts to
# downgrade where it is acceptable to fail.  It must be called with a
# second argument that is a true value.
BEGIN {
    if(defined(my $sub = _fetch_sub utf8 => 'downgrade')) {
	*downgrade = \&{"utf8::downgrade"};
    } else {
	*downgrade = sub {
	    my $r = "";
	    my $l = length($_[0]);
	    for(my $i = 0; $i != $l; $i++) {
		my $o = ord(substr($_[0], $i, 1));
		return if $o > 255;
		$r .= chr($o);
	    }
	    $_[0] = $r;
	};
    }
}

our $VERSION = '1.3301';

our $MaxEvalLen = 0;
our $Verbose    = 0;
our $CarpLevel  = 0;
our $MaxArgLen  = 64;    # How much of each argument to print. 0 = all.
our $MaxArgNums = 8;     # How many arguments to print. 0 = all.
our $RefArgFormatter = undef; # allow caller to format reference arguments

require Exporter;
our @ISA       = ('Exporter');
our @EXPORT    = qw(confess croak carp);
our @EXPORT_OK = qw(cluck verbose longmess shortmess);
our @EXPORT_FAIL = qw(verbose);    # hook to enable verbose mode

# The members of %Internal are packages that are internal to perl.
# Carp will not report errors from within these packages if it
# can.  The members of %CarpInternal are internal to Perl's warning
# system.  Carp will not report errors from within these packages
# either, and will not report calls *to* these packages for carp and
# croak.  They replace $CarpLevel, which is deprecated.    The
# $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
# text and function arguments should be formatted when printed.

our %CarpInternal;
our %Internal;

# disable these by default, so they can live w/o require Carp
$CarpInternal{Carp}++;
$CarpInternal{warnings}++;
$Internal{Exporter}++;
$Internal{'Exporter::Heavy'}++;

# if the caller specifies verbose usage ("perl -MCarp=verbose script.pl")
# then the following method will be called by the Exporter which knows
# to do this thanks to @EXPORT_FAIL, above.  $_[1] will contain the word
# 'verbose'.

sub export_fail { shift; $Verbose = shift if $_[0] eq 'verbose'; @_ }

sub _cgc {
    no strict 'refs';
    return \&{"CORE::GLOBAL::caller"} if defined &{"CORE::GLOBAL::caller"};
    return;
}

sub longmess {
    local($!, $^E);
    # Icky backwards compatibility wrapper. :-(
    #
    # The story is that the original implementation hard-coded the
    # number of call levels to go back, so calls to longmess were off
    # by one.  Other code began calling longmess and expecting this
    # behaviour, so the replacement has to emulate that behaviour.
    my $cgc = _cgc();
    my $call_pack = $cgc ? $cgc->() : caller();
    if ( $Internal{$call_pack} or $CarpInternal{$call_pack} ) {
        return longmess_heavy(@_);
    }
    else {
        local $CarpLevel = $CarpLevel + 1;
        return longmess_heavy(@_);
    }
}

our @CARP_NOT;

sub shortmess {
    local($!, $^E);
    my $cgc = _cgc();

    # Icky backwards compatibility wrapper. :-(
    local @CARP_NOT = $cgc ? $cgc->() : caller();
    shortmess_heavy(@_);
}

sub croak   { die shortmess @_ }
sub confess { die longmess @_ }
sub carp    { warn shortmess @_ }
sub cluck   { warn longmess @_ }

BEGIN {
    if("$]" >= 5.015002 || ("$]" >= 5.014002 && "$]" < 5.015) ||
	    ("$]" >= 5.012005 && "$]" < 5.013)) {
	*CALLER_OVERRIDE_CHECK_OK = sub () { 1 };
    } else {
	*CALLER_OVERRIDE_CHECK_OK = sub () { 0 };
    }
}

sub caller_info {
    my $i = shift(@_) + 1;
    my %call_info;
    my $cgc = _cgc();
    {
	# Some things override caller() but forget to implement the
	# @DB::args part of it, which we need.  We check for this by
	# pre-populating @DB::args with a sentinel which no-one else
	# has the address of, so that we can detect whether @DB::args
	# has been properly populated.  However, on earlier versions
	# of perl this check tickles a bug in CORE::caller() which
	# leaks memory.  So we only check on fixed perls.
        @DB::args = \$i if CALLER_OVERRIDE_CHECK_OK;
        package DB;
        @call_info{
            qw(pack file line sub has_args wantarray evaltext is_require) }
            = $cgc ? $cgc->($i) : caller($i);
    }

    unless ( defined $call_info{file} ) {
        return ();
    }

    my $sub_name = Carp::get_subname( \%call_info );
    if ( $call_info{has_args} ) {
        my @args;
        if (CALLER_OVERRIDE_CHECK_OK && @DB::args == 1
            && ref $DB::args[0] eq ref \$i
            && $DB::args[0] == \$i ) {
            @DB::args = ();    # Don't let anyone see the address of $i
            local $@;
            my $where = eval {
                my $func    = $cgc or return '';
                my $gv      =
                    (_fetch_sub B => 'svref_2object' or return '')
                        ->($func)->GV;
                my $package = $gv->STASH->NAME;
                my $subname = $gv->NAME;
                return unless defined $package && defined $subname;

                # returning CORE::GLOBAL::caller isn't useful for tracing the cause:
                return if $package eq 'CORE::GLOBAL' && $subname eq 'caller';
                " in &${package}::$subname";
            } || '';
            @args
                = "** Incomplete caller override detected$where; \@DB::args were not set **";
        }
        else {
            @args = @DB::args;
            my $overflow;
            if ( $MaxArgNums and @args > $MaxArgNums )
            {    # More than we want to show?
                $#args = $MaxArgNums;
                $overflow = 1;
            }

            @args = map { Carp::format_arg($_) } @args;

            if ($overflow) {
                push @args, '...';
            }
        }

        # Push the args onto the subroutine
        $sub_name .= '(' . join( ', ', @args ) . ')';
    }
    $call_info{sub_name} = $sub_name;
    return wantarray() ? %call_info : \%call_info;
}

# Transform an argument to a function into a string.
our $in_recurse;
sub format_arg {
    my $arg = shift;

    if ( ref($arg) ) {
         # legitimate, let's not leak it.
        if (!$in_recurse &&
	    do {
                local $@;
	        local $in_recurse = 1;
		local $SIG{__DIE__} = sub{};
                eval {$arg->can('CARP_TRACE') }
            })
        {
            return $arg->CARP_TRACE();
        }
        elsif (!$in_recurse &&
	       defined($RefArgFormatter) &&
	       do {
                local $@;
	        local $in_recurse = 1;
		local $SIG{__DIE__} = sub{};
                eval {$arg = $RefArgFormatter->($arg); 1}
                })
        {
            return $arg;
        }
        else
        {
	    my $sub = _fetch_sub(overload => 'StrVal');
	    return $sub ? &$sub($arg) : "$arg";
        }
    }
    return "undef" if !defined($arg);
    downgrade($arg, 1);
    return $arg if !(UTF8_REGEXP_PROBLEM && is_utf8($arg)) &&
	    $arg =~ /\A-?[0-9]+(?:\.[0-9]*)?(?:[eE][-+]?[0-9]+)?\z/;
    my $suffix = "";
    if ( 2 < $MaxArgLen and $MaxArgLen < length($arg) ) {
        substr ( $arg, $MaxArgLen - 3 ) = "";
	$suffix = "...";
    }
    if(UTF8_REGEXP_PROBLEM && is_utf8($arg)) {
	for(my $i = length($arg); $i--; ) {
	    my $c = substr($arg, $i, 1);
	    my $x = substr($arg, 0, 0);   # work around bug on Perl 5.8.{1,2}
	    if($c eq "\"" || $c eq "\\" || $c eq "\$" || $c eq "\@") {
		substr $arg, $i, 0, "\\";
		next;
	    }
	    my $o = ord($c);
	    substr $arg, $i, 1, sprintf("\\x{%x}", $o)
		if $o < 0x20 || $o > 0x7f;
	}
    } else {
	$arg =~ s/([\"\\\$\@])/\\$1/g;
	$arg =~ s/([^ -~])/sprintf("\\x{%x}",ord($1))/eg;
    }
    downgrade($arg, 1);
    return "\"".$arg."\"".$suffix;
}

sub Regexp::CARP_TRACE {
    my $arg = "$_[0]";
    downgrade($arg, 1);
    if(UTF8_REGEXP_PROBLEM && is_utf8($arg)) {
	for(my $i = length($arg); $i--; ) {
	    my $o = ord(substr($arg, $i, 1));
	    my $x = substr($arg, 0, 0);   # work around bug on Perl 5.8.{1,2}
	    substr $arg, $i, 1, sprintf("\\x{%x}", $o)
		if $o < 0x20 || $o > 0x7f;
	}
    } else {
	$arg =~ s/([^ -~])/sprintf("\\x{%x}",ord($1))/eg;
    }
    downgrade($arg, 1);
    my $suffix = "";
    if($arg =~ /\A\(\?\^?([a-z]*)(?:-[a-z]*)?:(.*)\)\z/s) {
	($suffix, $arg) = ($1, $2);
    }
    if ( 2 < $MaxArgLen and $MaxArgLen < length($arg) ) {
        substr ( $arg, $MaxArgLen - 3 ) = "";
	$suffix = "...".$suffix;
    }
    return "qr($arg)$suffix";
}

# Takes an inheritance cache and a package and returns
# an anon hash of known inheritances and anon array of
# inheritances which consequences have not been figured
# for.
sub get_status {
    my $cache = shift;
    my $pkg   = shift;
    $cache->{$pkg} ||= [ { $pkg => $pkg }, [ trusts_directly($pkg) ] ];
    return @{ $cache->{$pkg} };
}

# Takes the info from caller() and figures out the name of
# the sub/require/eval
sub get_subname {
    my $info = shift;
    if ( defined( $info->{evaltext} ) ) {
        my $eval = $info->{evaltext};
        if ( $info->{is_require} ) {
            return "require $eval";
        }
        else {
            $eval =~ s/([\\\'])/\\$1/g;
            return "eval '" . str_len_trim( $eval, $MaxEvalLen ) . "'";
        }
    }

    # this can happen on older perls when the sub (or the stash containing it)
    # has been deleted
    if ( !defined( $info->{sub} ) ) {
        return '__ANON__::__ANON__';
    }

    return ( $info->{sub} eq '(eval)' ) ? 'eval {...}' : $info->{sub};
}

# Figures out what call (from the point of view of the caller)
# the long error backtrace should start at.
sub long_error_loc {
    my $i;
    my $lvl = $CarpLevel;
    {
        ++$i;
        my $cgc = _cgc();
        my @caller = $cgc ? $cgc->($i) : caller($i);
        my $pkg = $caller[0];
        unless ( defined($pkg) ) {

            # This *shouldn't* happen.
            if (%Internal) {
                local %Internal;
                $i = long_error_loc();
                last;
            }
            elsif (defined $caller[2]) {
                # this can happen when the stash has been deleted
                # in that case, just assume that it's a reasonable place to
                # stop (the file and line data will still be intact in any
                # case) - the only issue is that we can't detect if the
                # deleted package was internal (so don't do that then)
                # -doy
                redo unless 0 > --$lvl;
                last;
            }
            else {
                return 2;
            }
        }
        redo if $CarpInternal{$pkg};
        redo unless 0 > --$lvl;
        redo if $Internal{$pkg};
    }
    return $i - 1;
}

sub longmess_heavy {
    return @_ if ref( $_[0] );    # don't break references as exceptions
    my $i = long_error_loc();
    return ret_backtrace( $i, @_ );
}

# Returns a full stack backtrace starting from where it is
# told.
sub ret_backtrace {
    my ( $i, @error ) = @_;
    my $mess;
    my $err = join '', @error;
    $i++;

    my $tid_msg = '';
    if ( defined &threads::tid ) {
        my $tid = threads->tid;
        $tid_msg = " thread $tid" if $tid;
    }

    my %i = caller_info($i);
    $mess = "$err at $i{file} line $i{line}$tid_msg";
    if( defined $. ) {
        local $@ = '';
        local $SIG{__DIE__};
        eval {
            CORE::die;
        };
        if($@ =~ /^Died at .*(, <.*?> line \d+).$/ ) {
            $mess .= $1;
        }
    }
    $mess .= "\.\n";

    while ( my %i = caller_info( ++$i ) ) {
        $mess .= "\t$i{sub_name} called at $i{file} line $i{line}$tid_msg\n";
    }

    return $mess;
}

sub ret_summary {
    my ( $i, @error ) = @_;
    my $err = join '', @error;
    $i++;

    my $tid_msg = '';
    if ( defined &threads::tid ) {
        my $tid = threads->tid;
        $tid_msg = " thread $tid" if $tid;
    }

    my %i = caller_info($i);
    return "$err at $i{file} line $i{line}$tid_msg\.\n";
}

sub short_error_loc {
    # You have to create your (hash)ref out here, rather than defaulting it
    # inside trusts *on a lexical*, as you want it to persist across calls.
    # (You can default it on $_[2], but that gets messy)
    my $cache = {};
    my $i     = 1;
    my $lvl   = $CarpLevel;
    {
        my $cgc = _cgc();
        my $called = $cgc ? $cgc->($i) : caller($i);
        $i++;
        my $caller = $cgc ? $cgc->($i) : caller($i);

        if (!defined($caller)) {
            my @caller = $cgc ? $cgc->($i) : caller($i);
            if (@caller) {
                # if there's no package but there is other caller info, then
                # the package has been deleted - treat this as a valid package
                # in this case
                redo if defined($called) && $CarpInternal{$called};
                redo unless 0 > --$lvl;
                last;
            }
            else {
                return 0;
            }
        }
        redo if $Internal{$caller};
        redo if $CarpInternal{$caller};
        redo if $CarpInternal{$called};
        redo if trusts( $called, $caller, $cache );
        redo if trusts( $caller, $called, $cache );
        redo unless 0 > --$lvl;
    }
    return $i - 1;
}

sub shortmess_heavy {
    return longmess_heavy(@_) if $Verbose;
    return @_ if ref( $_[0] );    # don't break references as exceptions
    my $i = short_error_loc();
    if ($i) {
        ret_summary( $i, @_ );
    }
    else {
        longmess_heavy(@_);
    }
}

# If a string is too long, trims it with ...
sub str_len_trim {
    my $str = shift;
    my $max = shift || 0;
    if ( 2 < $max and $max < length($str) ) {
        substr( $str, $max - 3 ) = '...';
    }
    return $str;
}

# Takes two packages and an optional cache.  Says whether the
# first inherits from the second.
#
# Recursive versions of this have to work to avoid certain
# possible endless loops, and when following long chains of
# inheritance are less efficient.
sub trusts {
    my $child  = shift;
    my $parent = shift;
    my $cache  = shift;
    my ( $known, $partial ) = get_status( $cache, $child );

    # Figure out consequences until we have an answer
    while ( @$partial and not exists $known->{$parent} ) {
        my $anc = shift @$partial;
        next if exists $known->{$anc};
        $known->{$anc}++;
        my ( $anc_knows, $anc_partial ) = get_status( $cache, $anc );
        my @found = keys %$anc_knows;
        @$known{@found} = ();
        push @$partial, @$anc_partial;
    }
    return exists $known->{$parent};
}

# Takes a package and gives a list of those trusted directly
sub trusts_directly {
    my $class = shift;
    no strict 'refs';
    my $stash = \%{"$class\::"};
    for my $var (qw/ CARP_NOT ISA /) {
        # Don't try using the variable until we know it exists,
        # to avoid polluting the caller's namespace.
        if ( $stash->{$var} && *{$stash->{$var}}{ARRAY} && @{$stash->{$var}} ) {
           return @{$stash->{$var}}
        }
    }
    return;
}

if(!defined($warnings::VERSION) ||
	do { no warnings "numeric"; $warnings::VERSION < 1.03 }) {
    # Very old versions of warnings.pm import from Carp.  This can go
    # wrong due to the circular dependency.  If Carp is invoked before
    # warnings, then Carp starts by loading warnings, then warnings
    # tries to import from Carp, and gets nothing because Carp is in
    # the process of loading and hasn't defined its import method yet.
    # So we work around that by manually exporting to warnings here.
    no strict "refs";
    *{"warnings::$_"} = \&$_ foreach @EXPORT;
}

1;

__END__