tools/trace-malloc/TraceMalloc.pm@ac0c01689b40
tools/trace-malloc/TraceMalloc.pm
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 # This Source Code Form is subject to the terms of the Mozilla Public
2 # License, v. 2.0. If a copy of the MPL was not distributed with this
3 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
4 package TraceMalloc;
6 use strict;
8 # Read in the type inference file and construct a network that we can
9 # use to match stack prefixes to types.
10 sub init_type_inference($) {
11 my ($file) = @_;
13 $::Fingerprints = { };
15 open(TYPES, "<$file") || die "unable to open $::opt_types, $!";
17 TYPE: while (<TYPES>) {
18 next TYPE unless /<(.*)>/;
19 my $type = $1;
21 my $link = \%::Fingerprints;
23 FRAME: while (<TYPES>) {
24 chomp;
25 last FRAME if /^$/;
27 my $next = $link->{$_};
28 if (! $next) {
29 $next = $link->{$_} = {};
30 }
31 $link = $next;
32 }
34 $link->{'#type#'} = $type;
36 last TYPE if eof;
37 }
38 }
40 # Infer the type, trying to find the most specific type possible.
41 sub infer_type($) {
42 my ($stack) = @_;
44 my $link = \%::Fingerprints;
45 my $last;
46 my $type = 'void*';
47 FRAME: foreach my $frame (@$stack) {
48 last FRAME unless $link;
50 $frame =~ s/\[.*\]$//; # ignore exact addresses, as they'll drift
52 $last = $link;
54 #
55 # Remember this type, but keep going. We use the longest match
56 # we find, but substacks of longer matches will also match.
57 #
58 if ($last->{'#type#'}) {
59 $type = $last->{'#type#'};
60 }
62 $link = $link->{$frame};
64 if (! $link) {
65 CHILD: foreach my $child (keys %$last) {
66 next CHILD unless $child =~ /^~/;
68 $child =~ s/^~//;
70 if ($frame =~ $child) {
71 $link = $last->{'~' . $child};
72 last CHILD;
73 }
74 }
75 }
76 }
78 return $type;
79 }
82 #----------------------------------------------------------------------
83 #
84 # Read in the output a trace malloc's dump.
85 #
86 sub read {
87 my ($callback, $noslop) = @_;
89 OBJECT: while (<>) {
90 # e.g., 0x0832FBD0 <void*> (80)
91 next OBJECT unless /^0x(\S+) <(.*)> \((\d+)\)/;
92 my ($addr, $type, $size) = (hex $1, $2, $3);
94 my $object = { 'type' => $type, 'size' => $size };
96 # Record the object's slots
97 my @slots;
99 SLOT: while (<>) {
100 # e.g., 0x00000000
101 last SLOT unless /^\t0x(\S+)/;
102 my $value = hex $1;
104 # Ignore low bits, unless they've specified --noslop
105 $value &= ~0x7 unless $noslop;
107 $slots[$#slots + 1] = $value;
108 }
110 $object->{'slots'} = \@slots;
112 # Record the stack by which the object was allocated
113 my @stack;
115 while (/^(.*)\[(.*) \+0x(\S+)\]$/) {
116 # e.g., _dl_debug_message[/lib/ld-linux.so.2 +0x0000B858]
117 my ($func, $lib, $off) = ($1, $2, hex $3);
119 chomp;
120 $stack[$#stack + 1] = $_;
122 $_ = <>;
123 }
125 $object->{'stack'} = \@stack;
127 $object->{'type'} = infer_type(\@stack)
128 if $object->{'type'} eq 'void*';
130 &$callback($object) if $callback;
132 # Gotta check EOF explicitly...
133 last OBJECT if eof;
134 }
135 }
137 1;
138 __END__
140 =head1 NAME
142 TraceMalloc - Perl routines to deal with output from ``trace malloc''
143 and the Boehm GC
145 =head1 SYNOPSIS
147 use TraceMalloc;
149 TraceMalloc::init_type_inference("types.dat");
150 TraceMalloc::read(0);
152 =head1 DESCRIPTION
154 =head1 EXAMPLES
156 =cut
