The Tor Browser: tools/rb/make-tree.pl@97036ab72558 (annotated)

tools/rb/make-tree.pl@97036ab72558 (annotated)

tools/rb/make-tree.pl

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rwxr-xr-x

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 #!/usr/bin/perl -w
 #
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 use 5.004;
 use strict;
 use Getopt::Long;
 $::opt_prune_depth = 0;
 $::opt_subtree_size = 0;
 $::opt_reverse = 0;
 # GetOption will create $opt_object & $opt_exclude, so ignore the
 # warning that gets spit out about those vbls.
 GetOptions("object=s", "exclude=s", "comptrs=s", "ignore-balanced", "subtree-size=i", "prune-depth=i",
             "collapse-to-method", "collapse-to-class", "old-style", "reverse");
 $::opt_object ||
      die qq{
 usage: leak.pl < logfile
   --object <obj>         The address of the object to examine (required)
   --exclude <file>       Exclude routines listed in <file>
   --comptrs <file>       Subtract all the data in the balanced COMPtr log <file>
   --ignore-balanced      Ignore balanced subtrees
   --subtree-size <n>     Print subtrees with more than <n> nodes separately
   --prune-depth <depth>  Prune the tree to <depth>
   --collapse-to-method   Aggregate data by method
   --collapse-to-class    Aggregate data by class (subsumes --collapse-to-method)
   --reverse              Reverse call stacks, showing leaves first
   --old-style            Old-style formatting
 };
 $::opt_prune_depth = 0 if $::opt_prune_depth < 0;
 $::opt_subtree_size = 0 if $::opt_subtree_size < 0;
 warn "object $::opt_object\n";
 warn "ignoring balanced subtrees\n" if $::opt_ignore_balanced;
 warn "prune depth $::opt_prune_depth\n" if $::opt_prune_depth;
 warn "collapsing to class\n" if $::opt_collapse_to_class;
 warn "collapsing to method\n" if $::opt_collapse_to_method && !$::opt_collapse_to_class;
 warn "reversing call stacks\n" if $::opt_reverse;
 # The 'excludes' are functions that, if detected in a particular call
 # stack, will cause the _entire_ call stack to be ignored. You might,
 # for example, explicitly exclude two functions that have a matching
 # AddRef/Release pair.
 my %excludes;
 if ($::opt_exclude) {
      open(EXCLUDE, "<".$::opt_exclude)
          || die "unable to open $::opt_exclude";
      while (<EXCLUDE>) {
          chomp $_;
          warn "excluding $_\n";
          $excludes{$_} = 1;
      }
 }
 # Each entry in the tree rooted by callGraphRoot contains the following:
 #   #name#      This call's name+offset string
 #   #refcount#  The net reference count of this call
 #   #label#     The label used for this subtree; only defined for labeled nodes
 #   #children#  List of children in alphabetical order
 # zero or more children indexed by method name+offset strings.
 my $callGraphRoot;
 $callGraphRoot = { '#name#' => '.root', '#refcount#' => 'n/a' };
 # The 'imbalance' is a gross count of how balanced a particular
 # callsite is. It is used to prune away callsites that are detected to
 # be balanced; that is, that have matching AddRef/Release() pairs.
 my %imbalance;
 $imbalance{'.root'} = 'n/a';
 # The main read loop.
 sub read_data($$$) {
      my ($INFILE, $plus, $minus) = @_;
      LINE: while (<$INFILE>) {
           next LINE if (! /^</);
           my @fields = split(/ /, $_);
           my $class = shift(@fields);
           my $obj   = shift(@fields);
           my $sno   = shift(@fields);
           next LINE unless ($obj eq $::opt_object);
           my $op  = shift(@fields);
           next LINE unless ($op eq $plus || $op eq $minus);
           my $cnt = shift(@fields);
           # Collect the remaining lines to create a stack trace.
           my @stack;
           CALLSITE: while (<$INFILE>) {
               chomp;
               last CALLSITE if (/^$/);
               $stack[++$#stack] = $_;
           }
           # Reverse the remaining fields to produce the call stack, with the
           # oldest frame at the front of the array.
           if (! $::opt_reverse) {
               @stack = reverse(@stack);
           }
           my $call;
           # If any of the functions in the stack are supposed to be excluded,
           # march on to the next line.
           foreach $call (@stack) {
               next LINE if exists($excludes{$call});
           }
           # Add the callstack as a path through the call graph, updating
           # refcounts at each node.
           my $caller = $callGraphRoot;
           foreach $call (@stack) {
               # Chop the method offset if we're 'collapsing to method' or
               # 'collapsing to class'.
               $call =~ s/\+0x.*$//g if ($::opt_collapse_to_method || $::opt_collapse_to_class);
               # Chop the method name if we're 'collapsing to class'.
               $call =~ s/::.*$//g if ($::opt_collapse_to_class);
               my $site = $caller->{$call};
               if (!$site) {
                   # This is the first time we've seen this callsite. Add a
                   # new entry to the call tree.
                   $site = { '#name#' => $call, '#refcount#' => 0 };
                   $caller->{$call} = $site;
               }
               if ($op eq $plus) {
                   ++($site->{'#refcount#'});
                   ++($imbalance{$call});
               } elsif ($op eq $minus) {
                   --($site->{'#refcount#'});
                   --($imbalance{$call});
               } else {
                   die "Bad operation $op";
               }
               $caller = $site;
           }
      }
 }
 read_data(*STDIN, "AddRef", "Release");
 if ($::opt_comptrs) {
      warn "Subtracting comptr log ". $::opt_comptrs . "\n";
      open(COMPTRS, "<".$::opt_comptrs)
          || die "unable to open $::opt_comptrs";
      # read backwards to subtract
      read_data(*COMPTRS, "nsCOMPtrRelease", "nsCOMPtrAddRef");
 }
 sub num_alpha {
      my ($aN, $aS, $bN, $bS);
      ($aN, $aS) = ($1, $2) if $a =~ /^(\d+) (.+)$/;
      ($bN, $bS) = ($1, $2) if $b =~ /^(\d+) (.+)$/;
      return $a cmp $b unless defined $aN && defined $bN;
      return $aN <=> $bN unless $aN == $bN;
      return $aS cmp $bS;
 }
 # Given a subtree and its nesting level, return true if that subtree should be pruned.
 # If it shouldn't be pruned, destructively attempt to prune its children.
 # Also compute the #children# properties of unpruned nodes.
 sub prune($$) {
      my ($site, $nest) = @_;
      # If they want us to prune the tree's depth, do so here.
      return 1 if ($::opt_prune_depth && $nest >= $::opt_prune_depth);
      # If the subtree is balanced, ignore it.
      return 1 if ($::opt_ignore_balanced && !$site->{'#refcount#'});
      my $name = $site->{'#name#'};
      # If the symbol isn't imbalanced, then prune here (and warn)
      if ($::opt_ignore_balanced && !$imbalance{$name}) {
          warn "discarding " . $name . "\n";
 #         return 1;
      }
      my @children;
      foreach my $child (sort num_alpha keys(%$site)) {
          if (substr($child, 0, 1) ne '#') {
              if (prune($site->{$child}, $nest + 1)) {
                  delete $site->{$child};
              } else {
                  push @children, $site->{$child};
              }
          }
      }
      $site->{'#children#'} = \@children;
      return 0;
 }
 # Compute the #label# properties of this subtree.
 # Return the subtree's number of nodes, not counting nodes reachable
 # through a labeled node.
 sub createLabels($) {
      my ($site) = @_;
      my @children = @{$site->{'#children#'}};
      my $nChildren = @children;
      my $nDescendants = 0;
      foreach my $child (@children) {
          my $childDescendants = createLabels($child);
          if ($nChildren > 1 && $childDescendants > $::opt_subtree_size) {
              die "Internal error" if defined($child->{'#label#'});
              $child->{'#label#'} = "__label__";
              $childDescendants = 1;
          }
          $nDescendants += $childDescendants;
      }
      return $nDescendants + 1;
 }
 my $nextLabel = 0;
 my @labeledSubtrees;
 sub list($$$$$) {
      my ($site, $nest, $nestStr, $childrenLeft, $root) = @_;
      my $label = !$root && $site->{'#label#'};
      # Assign a unique number to the label.
      if ($label) {
          die unless $label eq "__label__";
          $label = "__" . ++$nextLabel . "__";
          $site->{'#label#'} = $label;
          push @labeledSubtrees, $site;
      }
      print $nestStr;
      if ($::opt_old_style) {
          print $label, " " if $label;
          print $site->{'#name#'}, ": bal=", $site->{'#refcount#'}, "\n";
      } else {
          my $refcount = $site->{'#refcount#'};
          my $l = 8 - length $refcount;
          $l = 1 if $l < 1;
          print $refcount, " " x $l;
          print $label, " " if $label;
          print $site->{'#name#'}, "\n";
      }
      $nestStr .= $childrenLeft && !$::opt_old_style ? "| " : "  ";
      if (!$label) {
          my @children = @{$site->{'#children#'}};
          $childrenLeft = @children;
          foreach my $child (@children) {
              $childrenLeft--;
              list($child, $nest + 1, $nestStr, $childrenLeft);
          }
      }
 }
 if (!prune($callGraphRoot, 0)) {
      createLabels $callGraphRoot if ($::opt_subtree_size);
      list $callGraphRoot, 0, "", 0, 1;
      while (@labeledSubtrees) {
          my $labeledSubtree = shift @labeledSubtrees;
          print "\n------------------------------\n",
 $labeledSubtree->{'#label#'}, "\n";
          list $labeledSubtree, 0, "", 0, 1;
      }
      print "\n------------------------------\n" if @labeledSubtrees;
 }
 print qq{
 Imbalance
 ---------
 };
 foreach my $call (sort num_alpha keys(%imbalance)) {
      print $call . " " . $imbalance{$call} . "\n";
 }

The Tor Browser / annotate

tools/rb/make-tree.pl@97036ab72558 (annotated)

tools/rb/make-tree.pl