This file is indexed.

/usr/bin/dpkg-depcheck is in devscripts 2.17.12ubuntu1.

This file is owned by root:root, with mode 0o755.

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
#!/usr/bin/perl

# Copyright Bill Allombert <ballombe@debian.org> 2001.
# Modifications copyright 2002-2005 Julian Gilbey <jdg@debian.org>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.

use strict;
use warnings;
use 5.006_000;  # our() commands
use Cwd;
use File::Basename;
use Getopt::Long;

use Devscripts::Set;
use Devscripts::Packages;
use Devscripts::PackageDeps;

# Function prototypes
sub process_features ($$);
sub getusedfiles (@);
sub filterfiles (@);

# Global options
our %opts;

# A list of files that do not belong to a Debian package but are known
# to never create a dependency
our @known_files = ("/etc/ld.so.cache", "/etc/dpkg/shlibs.default",
		    "/etc/dpkg/dpkg.cfg", "/etc/devscripts.conf");

# This will be given information about features later on
our (%feature, %default_feature);

my $progname=basename($0);
my $modified_conf_msg;

sub usage ()
{
    my @ed=("disabled","enabled");
    print <<"EOF";
Usage:
  $progname [options] <command>
Run <command> and then output packages used to do this.
Options:
  Which packages to report:
    -a, --all              Report all packages used to run <command>
    -b, --build-depends    Do not report build-essential or essential packages
                           used or any of their (direct or indirect)
                           dependencies
    -d, --ignore-dev-deps  Do not show packages used which are direct
                           dependencies of -dev packages used
    -m, --min-deps         Output a minimal set of packages needed, taking
                           into account direct dependencies
    -m implies -d and both imply -b; -a gives additional dependency information
    if used in conjunction with -b, -d or -m

  -C, --C-locale           Run command with C locale
  --no-C-locale            Don\'t change locale
  -l, --list-files         Report list of files used in each package
  --no-list-files          Do not report list of files used in each package
  -o, --output=FILE        Output diagnostic to FILE instead of stdout
  -O, --strace-output=FILE Write strace output to FILE when tracing <command>
                           instead of a temporary file
  -I, --strace-input=FILE  Get strace output from FILE instead of tracing
                           <command>; strace must be run with -f -q for this
                           to work

  -f, --features=LIST      Enable or disabled features given in
                           comma-separated LIST as follows:
    +feature or feature      enable feature
    -feature                 disable feature

    Known features and default setting:
      warn-local             ($ed[$default_feature{'warn-local'}]) warn if files in /usr/local are used
      discard-check-version  ($ed[$default_feature{'discard-check-version'}]) discard execve with only
                             --version argument; this works around some
                             configure scripts that check for binaries they
                             don\'t use
      trace-local            ($ed[$default_feature{'trace-local'}]) also try to identify file
                             accesses in /usr/local
      catch-alternatives     ($ed[$default_feature{'catch-alternatives'}]) catch access to alternatives
      discard-sgml-catalogs  ($ed[$default_feature{'discard-sgml-catalogs'}]) discard access to SGML
                             catalogs; some SGML tools read all the
                             registered catalogs at startup.

  --no-conf, --noconf        Don\'t read devscripts config files;
                             must be the first option given
  -h, --help                 Display this help and exit
  -v, --version              Output version information and exit

Default settings modified by devscripts configuration files:
$modified_conf_msg
EOF
}


sub version ()
{
    print <<'EOF';
This is $progname, from the Debian devscripts package, version 2.17.12ubuntu1
Copyright Bill Allombert <ballombe@debian.org> 2001.
Modifications copyright 2002, 2003 Julian Gilbey <jdg@debian.org>
This program comes with ABSOLUTELY NO WARRANTY.
You are free to redistribute this code under the terms of the
GNU General Public License, version 2 or later.
EOF
}


# Main program

# Features:
# This are heuristics used to speed up the process.
# Since thay may be considered as "kludges" or worse "bugs"
# by some, they can be deactivated
# 0 disabled by default, 1 enabled by default.
%feature=(
	  "warn-local"=>1, "discard-check-version"=>1,
	  "trace-local"=>0, "catch-alternatives"=>1,
          "discard-sgml-catalogs"=>1,
	  );
%default_feature = %feature;

# First process configuration file options, then check for command-line
# options.  This is pretty much boilerplate.

if (@ARGV and $ARGV[0] =~ /^--no-?conf$/) {
    $modified_conf_msg = "  (no configuration files read)";
    shift;
} else {
    my @config_files = ('/etc/devscripts.conf', '~/.devscripts');
    my %config_vars = (
		       'DPKG_DEPCHECK_OPTIONS' => '',
		       );
    my %config_default = %config_vars;

    my $shell_cmd;
    # Set defaults
    foreach my $var (keys %config_vars) {
	$shell_cmd .= qq[$var="$config_vars{$var}";\n];
    }
    $shell_cmd .= 'for file in ' . join(" ",@config_files) . "; do\n";
    $shell_cmd .= '[ -f $file ] && . $file; done;' . "\n";
    # Read back values
    foreach my $var (keys %config_vars) { $shell_cmd .= "echo \$$var;\n" }
    my $shell_out = `/bin/bash -c '$shell_cmd'`;
    @config_vars{keys %config_vars} = split /\n/, $shell_out, -1;

    foreach my $var (sort keys %config_vars) {
	if ($config_vars{$var} ne $config_default{$var}) {
	    $modified_conf_msg .= "  $var=$config_vars{$var}\n";
	}
    }
    $modified_conf_msg ||= "  (none)\n";
    chomp $modified_conf_msg;

    if ($config_vars{'DPKG_DEPCHECK_OPTIONS'} ne '') {
	unshift @ARGV, split(' ', $config_vars{'DPKG_DEPCHECK_OPTIONS'});
    }
}

# Default option:
$opts{"pkgs"} = 'all';
$opts{"allpkgs"} = 0;

Getopt::Long::Configure('bundling','require_order');
GetOptions("h|help" => sub { usage(); exit; },
           "v|version" => sub { version(); exit; },
           "a|all" => sub { $opts{"allpkgs"}=1; },
           "b|build-depends" => sub { $opts{"pkgs"}='build'; },
           "d|ignore-dev-deps" => sub { $opts{"pkgs"}='dev'; },
           "m|min-deps" => sub { $opts{"pkgs"}='min'; },
           "C|C-locale" => \$opts{"C"},
           "no-C-locale|noC-locale" => sub { $opts{"C"}=0; },
           "l|list-files" => \$opts{"l"},
           "no-list-files|nolist-files" => sub { $opts{"l"}=0; },
           "o|output=s" => \$opts{"o"},
           "O|strace-output=s" => \$opts{"strace-output"},
           "I|strace-input=s" => \$opts{"strace-input"},
           "f|features=s" => \&process_features,
           "no-conf" => \$opts{"noconf"},
           "noconf" => \$opts{"noconf"},
           ) or do { usage; exit 1; };

if ($opts{"noconf"}) {
    die "$progname: --no-conf is only acceptable as the first command-line option!\n";
}

if ($opts{"pkgs"} eq 'all') {
    $opts{"allpkgs"} = 0;
} else {
    # We don't initialise the packages database before doing this check,
    # as that takes quite some time
    unless (system('dpkg -L build-essential >/dev/null 2>&1') >> 8 == 0) {
	die "You must have the build-essential package installed or use the --all option\n";
    }
}


@ARGV > 0 or $opts{"strace-input"} or
    die "You need to specify a command!  Run $progname --help for more info\n";

# Run the command and trace it to see what's going on
my @usedfiles = getusedfiles(@ARGV);

if ($opts{"o"}) {
    $opts{"o"} =~ s%^(\s)%./$1%;
    open STDOUT,"> $opts{'o'}" or
	warn "Cannot open $opts{'o'} for writing: $!\nTrying to use stdout instead\n";
} else {
    # Visual space
    print "\n\n";
    print '-' x 70, "\n";
}

# Get each file once only, and drop any we are not interested in.
# Also, expand all symlinks so we get full pathnames of the real file accessed.
@usedfiles = filterfiles(@usedfiles);

# Forget about the few files we are expecting to see but can ignore
@usedfiles = SetMinus(\@usedfiles, \@known_files);

# For a message at the end
my $number_files_used = scalar @usedfiles;

# Initialise the packages database unless --all is given
my $packagedeps;

# @used_ess_files will contain those files used which are in essential packages
my @used_ess_files;

# Exclude essential and build-essential packages?
if ($opts{"pkgs"} ne 'all')
{
    $packagedeps = new Devscripts::PackageDeps ('/var/lib/dpkg/status');
    my @essential = PackagesMatch('^Essential: yes$');
    my @essential_packages =
	$packagedeps->full_dependencies('build-essential', @essential);
    my @essential_files = PackagesToFiles(@essential_packages);
    @used_ess_files = SetInter(\@usedfiles,\@essential_files);
    @usedfiles = SetMinus(\@usedfiles,\@used_ess_files);
}

# Now let's find out which packages are used...
my @ess_packages = FilesToPackages(@used_ess_files);
my @packages = FilesToPackages(@usedfiles);
my %dep_packages = ();  # packages which are depended upon by others

# ... and remove their files from the filelist
if ($opts{"l"}) {
    # Have to do it slowly :-(
    if ($opts{"allpkgs"}) {
	print "Files used in each of the needed build-essential or essential packages:\n";
	foreach my $pkg (sort @ess_packages) {
	    my @pkgfiles = PackagesToFiles($pkg);
	    print "Files used in (build-)essential package $pkg:\n  ",
	    join("\n  ", SetInter(\@used_ess_files, \@pkgfiles)), "\n";
	}
	print "\n";
    }
    print "Files used in each of the needed packages:\n";
    foreach my $pkg (sort @packages) {
	my @pkgfiles = PackagesToFiles($pkg);
	print "Files used in package $pkg:\n  ",
	    join("\n  ", SetInter(\@usedfiles, \@pkgfiles)), "\n";
	# We take care to note any files used which
	# do not appear in any package
	@usedfiles = SetMinus(\@usedfiles, \@pkgfiles);
    }
    print "\n";
} else {
    # We take care to note any files used which
    # do not appear in any package
    my @pkgfiles = PackagesToFiles(@packages);
    @usedfiles = SetMinus(\@usedfiles, \@pkgfiles);
}

if ($opts{"pkgs"} eq 'dev') {
    # We also remove any direct dependencies of '-dev' packages
    my %pkgs;
    @pkgs{@packages} = (1) x @packages;

    foreach my $pkg (@packages) {
	next unless $pkg =~ /-dev$/;
	my @deps = $packagedeps->dependencies($pkg);
	foreach my $dep (@deps) {
	    $dep = $$dep[0] if ref $dep;
	    if (exists $pkgs{$dep}) {
		$dep_packages{$dep} = $pkg;
		delete $pkgs{$dep};
	    }
	}
    }

    @packages = keys %pkgs;
}
elsif ($opts{"pkgs"} eq 'min') {
    # Do a mindep job on the package list
    my ($packages_ref,$dep_packages_ref) =
	$packagedeps->min_dependencies(@packages);
    @packages = @$packages_ref;
    %dep_packages = %$dep_packages_ref;
}

print "Summary: $number_files_used files considered.\n" if $opts{"l"};
# Ignore unrecognised /var/... files
@usedfiles = grep ! /^\/var\//, @usedfiles;
if (@usedfiles) {
    warn "The following files did not appear to belong to any package:\n";
    warn join("\n", @usedfiles) . "\n";
}

print "Packages ", ($opts{"pkgs"} eq 'all') ? "used" : "needed", ":\n  ";
print join("\n  ", @packages), "\n";

if ($opts{"allpkgs"}) {
    if (@ess_packages) {
	print "\n(Build-)Essential packages used:\n  ";
	print join("\n  ", @ess_packages), "\n";
    } else {
	print "\nNo (Build-)Essential packages used\n";
    }

    if (scalar keys %dep_packages) {
	print "\nOther packages used with depending packages listed:\n";
	foreach my $pkg (sort keys %dep_packages) {
	    print "  $pkg  <=  $dep_packages{$pkg}\n";
	}
    }
}

exit 0;


### Subroutines

# This sub is handed two arguments: f or feature, and the setting

sub process_features ($$)
{
    foreach (split(',', $_[1])) {
	my $state=1;
	m/^-/ and $state=0;
	s/^[-+]//;
	if (exists $feature{$_}) {
	    $feature{$_}=$state;
	} else {
	    die("Unknown feature $_\n");
	}
    }
}


# Get used files.  This runs the requested command (given as parameters
# to this sub) under strace and then parses the output, returning a list
# of all absolute filenames successfully opened or execve'd.

sub getusedfiles (@)
{
    my $file;
    if ($opts{"strace-input"}) {
	$file=$opts{"strace-input"};
    }
    else {
	my $old_locale = $ENV{'LC_ALL'} || undef;
	$file = $opts{"strace-output"} || `tempfile -p depcheck`;
	chomp $file;
	$file =~ s%^(\s)%./$1%;
	my @strace_cmd=('strace', '-e', 'trace=open,execve',  '-f',
			'-q', '-o', $file, @_);
	$ENV{'LC_ALL'}="C" if $opts{"C"};
	system(@strace_cmd);
	$? >> 8 == 0 or
	    die "Running strace failed (command line:\n@strace_cmd\n";
	if (defined $old_locale) { $ENV{'LC_ALL'} = $old_locale; }
	else { delete $ENV{'LC_ALL'}; }
    }

    my %openfiles=();
    open FILE, $file or die "Cannot open $file for reading: $!\n";
    while (<FILE>) {
	# We only consider absolute filenames
	m/^\d+\s+(\w+)\(\"(\/.*?)\",.*\) = (-?\d+)/ or next;
	my ($syscall, $filename, $status) = ($1, $2, $3);
	if ($syscall eq 'open') { next unless $status >= 0; }
	elsif ($syscall eq 'execve') { next unless $status == 0; }
	else { next; }  # unrecognised syscall
	next if $feature{"discard-check-version"} and
	    m/execve\(\"\Q$filename\E\", \[\"[^\"]+\", "--version"\], /;
	# So it's a real file
	$openfiles{$filename}=1;
    }

    unlink $file unless $opts{"strace-input"} or $opts{"strace-output"};

    return keys %openfiles;
}


# Select those files which we are interested in, as determined by the
# user-specified options

sub filterfiles (@)
{
    my %files=();
    my %local_files=();
    my %alternatives=();
    my $pwd=cwd();

    foreach my $file (@_) {
	next unless -f $file;
	$file = Cwd::abs_path($file);

	my @links=();
	my $prevlink='';
	foreach (ListSymlinks($file, $pwd)) {
	    if (m%^/(usr|var)/local(/|\z)%) {
		$feature{"warn-local"} and $local_files{$_} = 1;
		unless ($feature{"trace-local"}) {
		    $prevlink = $_;
		    next;
		}
	    }
	    elsif ($feature{"discard-sgml-catalogs"} and
		   m%^/usr/share/(sgml/.*\.cat|.*/catalog)%) {
		next;
	    }
	    elsif ($feature{"catch-alternatives"} and m%^/etc/alternatives/%) {
		$alternatives{"$prevlink --> " . readlink($_)} = 1
		    if $prevlink;
	    }
	    $prevlink=$_;
	    # If it's not in one of these dirs, we skip it
	    next unless m%^/(bin|etc|lib|sbin|usr|var)%;
	    push @links, $_;
	}

	@files{@links} = (1) x @links;
    }

    if (keys %local_files) {
	print "warning: files in /usr/local or /var/local used:\n",
	    join("\n", sort keys %local_files), "\n";
    }
    if (keys %alternatives) {
	print "warning: alternatives used:\n",
	    join("\n", sort keys %alternatives), "\n";
    }

    return keys %files;
}



# The purpose here is to find out all the symlinks crossed by a file access.
# We work from the end of the filename (basename) back towards the root of
# the filename (solving bug#246006 where /usr is a symlink to another
# filesystem), repeating this process until we end up with an absolute
# filename with no symlinks in it.  We return a list of all of the
# full filenames encountered.
# For example, if /usr -> /moved/usr, then
# /usr/bin/X11/xapp would yield:
# /usr/bin/X11/xapp, /usr/X11R6/bin/xapp, /moved/usr/X11R6/bin/xapp

# input: file, pwd
# output: if symlink found: (readlink-replaced file, prefix)
#         if not: (file, '')

sub NextSymlink ($)
{
    my $file = shift;

    my $filestart = $file;
    my $fileend = '';

    while ($filestart ne '/') {
	if (-l $filestart) {
	    my $link = readlink($filestart);
	    my $parent = dirname $filestart;
	    if ($link =~ m%^/%) { # absolute symlink
		return $link . $fileend;
	    }
	    while ($link =~ s%^\./%%) { }
	    # The following is not actually correct: if we have
	    # /usr -> /moved/usr and /usr/mylib -> ../mylibdir, then
	    # /usr/mylib should resolve to /moved/mylibdir, not /mylibdir
	    # But if we try to take this into account, we would need to
	    # use something like Cwd(), which would immediately resolve
	    # /usr -> /moved/usr, losing us the opportunity of recognising
	    # the filename we want.  This is a bug we'll probably have to
	    # cope with.
	    # One way of doing this correctly would be to have a function
	    # resolvelink which would recursively resolve any initial ../ in
	    # symlinks, but no more than that.  But I don't really want to
	    # implement this unless it really proves to be necessary:
	    # people shouldn't be having evil symlinks like that on their
	    # system!!
	    while ($link =~ s%^\.\./%%) { $parent = dirname $parent; }
	    return $parent . '/' . $link . $fileend;
	}
	else {
	    $fileend = '/' . basename($filestart) . $fileend;
	    $filestart = dirname($filestart);
	}
    }
    return undef;
}


# input: file, pwd
# output: list of full filenames encountered en route

sub ListSymlinks ($$)
{
    my ($file, $path) = @_;

    if ($file !~ m%^/%) { $file = "$path/$file"; }

    my @fn = ($file);

    while ($file = NextSymlink($file)) {
	push @fn, $file;
    }

    return @fn;
}