#!/usr/bin/perl # vim:sw=4:ts=4:et: # ***** BEGIN LICENSE BLOCK ***** # Version: MPL 1.1/GPL 2.0/LGPL 2.1 # # The contents of this file are subject to the Mozilla Public License Version # 1.1 (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # http://www.mozilla.org/MPL/ # # Software distributed under the License is distributed on an "AS IS" basis, # WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License # for the specific language governing rights and limitations under the # License. # # The Original Code is fix-linux-stack.pl. # # The Initial Developer of the Original Code is L. David Baron. # Portions created by the Initial Developer are Copyright (C) 2003 # the Initial Developer. All Rights Reserved. # # Contributor(s): # L. David Baron (original author) # # Alternatively, the contents of this file may be used under the terms of # either the GNU General Public License Version 2 or later (the "GPL"), or # the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), # in which case the provisions of the GPL or the LGPL are applicable instead # of those above. If you wish to allow use of your version of this file only # under the terms of either the GPL or the LGPL, and not to allow others to # use your version of this file under the terms of the MPL, indicate your # decision by deleting the provisions above and replace them with the notice # and other provisions required by the GPL or the LGPL. If you do not delete # the provisions above, a recipient may use your version of this file under # the terms of any one of the MPL, the GPL or the LGPL. # # ***** END LICENSE BLOCK ***** # $Id: fix-linux-stack.pl,v 1.15 2007-06-20 22:01:17 dbaron%dbaron.org Exp $ # # This script uses addr2line (part of binutils) to process the output of # nsTraceRefcnt's Linux stack walking code. This is useful for two # things: # (1) Getting line number information out of # |nsTraceRefcntImpl::WalkTheStack|'s output in debug builds. # (2) Getting function names out of |nsTraceRefcntImpl::WalkTheStack|'s # output on optimized builds (where it mostly prints UNKNOWN # because only a handful of symbols are exported from component # libraries). # # Use the script by piping output containing stacks (such as raw stacks # or make-tree.pl balance trees) through this script. use strict; use IPC::Open2; use File::Basename; # XXX Hard-coded to gdb defaults (works on Fedora). my $global_debug_dir = '/usr/lib/debug'; # addr2line wants offsets relative to the base address for shared # libraries, but it wants addresses including the base address offset # for executables. This function returns the appropriate address # adjustment to add to an offset within file. See bug 230336. my %address_adjustments; sub address_adjustment($) { my ($file) = @_; unless (exists $address_adjustments{$file}) { # find out if it's an executable (as opposed to a shared library) my $elftype; open(ELFHDR, '-|', 'readelf', '-h', $file); while () { if (/^\s*Type:\s+(\S+)/) { $elftype = $1; last; } } close(ELFHDR); # If it's an executable, make adjustment the base address. # Otherwise, leave it zero. my $adjustment = 0; if ($elftype eq 'EXEC') { open(ELFSECS, '-|', 'readelf', '-S', $file); while () { if (/^\s*\[\s*\d+\]\s+\.text\s+\w+\s+(\w+)\s+(\w+)\s+/) { # Subtract the .text section's offset within the # file from its base address. $adjustment = hex($1) - hex($2); last; } } close(ELFSECS); } $address_adjustments{$file} = $adjustment; } return $address_adjustments{$file}; } # Files sometimes contain a link to a separate object file that contains # the debug sections of the binary, removed so that a smaller file can # be shipped, but kept separately so that it can be obtained by those # who want it. # See http://sources.redhat.com/gdb/current/onlinedocs/gdb_16.html#SEC154 # for documentation of debugging information in separate files. # On Fedora distributions, these files can be obtained by installing # *-debuginfo RPM packages. sub separate_debug_file_for($) { my ($file) = @_; # We can read the .gnu_debuglink section using either of: # objdump -s --section=.gnu_debuglink $file # readelf -x .gnu_debuglink $file # Since readelf prints things backwards on little-endian platforms # for some versions only (backwards on Fedora Core 6, forwards on # Fedora 7), use objdump. # See if there's a .gnu_debuglink section my $have_debuglink = 0; open(ELFSECS, '-|', 'readelf', '-S', $file); while () { if (/^\s*\[\s*\d+\]\s+\.gnu_debuglink\s+\w+\s+(\w+)\s+(\w+)\s+/) { $have_debuglink = 1; last; } } close(ELFSECS); return '' unless ($have_debuglink); # Determine the endianness of the shared library. my $endian = ''; open(ELFHDR, '-|', 'readelf', '-h', $file); while () { if (/^\s*Data:\s+.*(little|big) endian.*$/) { $endian = $1; last; } } close(ELFHDR); if ($endian ne 'little' && $endian ne 'big') { print STDERR "Warning: could not determine endianness of $file.\n"; return ''; } # Read the debuglink section as an array of words, in hexidecimal. open(DEBUGLINK, '-|', 'objdump', '-s', '--section=.gnu_debuglink', $file); my @words; while () { if ($_ =~ /^ [0-9a-f]* ([0-9a-f ]{8}) ([0-9a-f ]{8}) ([0-9a-f ]{8}) ([0-9a-f ]{8}).*/) { push @words, $1, $2, $3, $4; } } close(DEBUGLINK); while (@words[$#words] eq ' ') { pop @words; } if ($#words < 1) { print STDERR "Warning: .gnu_debuglink section in $file too short.\n"; return ''; } my @chars; while ($#words >= 0) { my $w = shift @words; if ($w =~ /^([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})$/) { push @chars, $1, $2, $3, $4; } else { print STDERR "Warning: malformed objdump output for $file.\n"; return ''; } } my @hash_bytes = map(hex, @chars[$#chars - 3 .. $#chars]); $#chars -= 4; my $hash; if ($endian eq 'little') { $hash = ($hash_bytes[3] << 24) | ($hash_bytes[2] << 16) | ($hash_bytes[1] << 8) | $hash_bytes[0]; } else { $hash = ($hash_bytes[0] << 24) | ($hash_bytes[1] << 16) | ($hash_bytes[2] << 8) | $hash_bytes[3]; } my $old_num = $#chars; while ($chars[$#chars] eq '00') { pop @chars; } if ($old_num == $#chars || $old_num - 4 > $#chars) { print STDERR "Warning: malformed .gnu_debuglink section in $file.\n"; return ''; } my $basename = join('', map { chr(hex($_)) } @chars); # Now $basename and $hash represent the information in the # .gnu_debuglink section. #printf STDERR "%x: %s\n", $hash, $basename; my @possible_results = ( dirname($file) . $basename, dirname($file) . '.debug/' . $basename, $global_debug_dir . dirname($file) . '/' . $basename ); foreach my $result (@possible_results) { if (-f $result) { # XXX We should check the hash. return $result; } } return ''; } # Return a reference to a hash whose {read} and {write} entries are a # bidirectional pipe to an addr2line process that gives symbol # information for a file. my %pipes; sub addr2line_pipe($) { my ($file) = @_; my $pipe; unless (exists $pipes{$file}) { my $debug_file = separate_debug_file_for($file); $debug_file = $file if ($debug_file eq ''); my $pid = open2($pipe->{read}, $pipe->{write}, '/usr/bin/addr2line', '-C', '-f', '-e', $debug_file); $pipes{$file} = $pipe; } else { $pipe = $pipes{$file}; } return $pipe; } while (<>) { my $line = $_; if ($line =~ /^([ \|0-9-]*)(.*) ?\[([^ ]*) \+(0x[0-9A-F]{1,8})\](.*)$/) { my $before = $1; # allow preservation of balance trees my $badsymbol = $2; my $file = $3; my $address = hex($4); my $after = $5; # allow preservation of counts if (-f $file) { my $pipe = addr2line_pipe($file); $address += address_adjustment($file); my $out = $pipe->{write}; my $in = $pipe->{read}; printf {$out} "0x%X\n", $address; chomp(my $symbol = <$in>); chomp(my $fileandline = <$in>); if ($symbol eq '??') { $symbol = $badsymbol; } if ($fileandline eq '??:0') { $fileandline = $file; } print "$before$symbol ($fileandline)$after\n"; } else { print STDERR "Warning: File \"$file\" does not exist.\n"; print $line; } } else { print $line; } }