Recent 2.5 kernels needed a tweak, the code also works for older
kernels, including 2.4.
#!/usr/bin/perl -w
#
# reference_discarded.pl (C) Keith Owens 2001 <kaos@ocs.com.au>
#
# List dangling references to vmlinux discarded sections.
use strict;
die($0 . " takes no arguments\n") if($#ARGV >= 0);
my %object;
my $object;
my $line;
my $ignore;
$| = 1;
printf("Finding objects, ");
open(OBJDUMP_LIST, "find . -name '*.o' | xargs objdump -h |") || die "getting objdump list failed";
while (defined($line = <OBJDUMP_LIST>)) {
chomp($line);
if ($line =~ /:\s+file format/) {
($object = $line) =~ s/:.*//;
$object{$object}->{'module'} = 0;
$object{$object}->{'size'} = 0;
$object{$object}->{'off'} = 0;
}
if ($line =~ /^\s*\d+\s+\.modinfo\s+/) {
$object{$object}->{'module'} = 1;
}
if ($line =~ /^\s*\d+\s+\.comment\s+/) {
($object{$object}->{'size'}, $object{$object}->{'off'}) = (split(' ', $line))[2,5];
}
}
close(OBJDUMP_LIST);
printf("%d objects, ", scalar keys(%object));
$ignore = 0;
foreach $object (keys(%object)) {
if ($object{$object}->{'module'}) {
++$ignore;
delete($object{$object});
}
}
printf("ignoring %d module(s)\n", $ignore);
# Ignore conglomerate objects, they have been built from multiple objects and we
# only care about the individual objects. If an object has more than one GCC:
# string in the comment section then it is conglomerate. This does not filter
# out conglomerates that consist of exactly one object, can't be helped.
printf("Finding conglomerates, ");
$ignore = 0;
foreach $object (keys(%object)) {
if (exists($object{$object}->{'off'})) {
my ($off, $size, $comment, $l);
$off = hex($object{$object}->{'off'});
$size = hex($object{$object}->{'size'});
open(OBJECT, "<$object") || die "cannot read $object";
seek(OBJECT, $off, 0) || die "seek to $off in $object failed";
$l = read(OBJECT, $comment, $size);
die "read $size bytes from $object .comment failed" if ($l != $size);
close(OBJECT);
if ($comment =~ /GCC\:.*GCC\:/m) {
++$ignore;
delete($object{$object});
}
}
}
printf("ignoring %d conglomerate(s)\n", $ignore);
printf("Scanning objects\n");
foreach $object (keys(%object)) {
my $from;
open(OBJDUMP, "objdump -r $object|") || die "cannot objdump -r $object";
while (defined($line = <OBJDUMP>)) {
chomp($line);
if ($line =~ /RELOCATION RECORDS FOR /) {
($from = $line) =~ s/.*\[([^]]*).*/$1/;
}
if (($line =~ /\.text\.exit$/ ||
$line =~ /\.exit\.text$/ ||
$line =~ /\.data\.exit$/ ||
$line =~ /\.exit\.data$/ ||
$line =~ /\.exitcall\.exit$/) &&
($from !~ /\.text\.exit$/ &&
$from !~ /\.exit\.text$/ &&
$from !~ /\.data\.exit$/ &&
$from !~ /\.exit\.data$/ &&
$from !~ /\.exitcall\.exit$/ &&
$from !~ /\.stab$/)) {
printf("Error: %s %s refers to %s\n", $object, $from, $line);
}
}
close(OBJDUMP);
}
printf("Done\n");
--
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