use File::Basename;

use Math::BigInt;

use Getopt::Long;

my $cross_compile = "";

my $vmlinux_name = "";

my $modulefile = "";

Getopt::Long::GetOptions(

'cross-compile|c=s' => \$cross_compile,

'module|m=s' => \$modulefile,

'help|h' => \&usage,

) || usage ();

my $vmlinux_name = $ARGV[0];

if (!defined($vmlinux_name)) {

my $kerver = `uname -r`;

chomp($kerver);

$vmlinux_name = "/lib/modules/$kerver/build/vmlinux";

print "No vmlinux specified, assuming $vmlinux_name\n";

}

my $filename = $vmlinux_name;

my $target = "0";

my $function;

my $module = "";

my $func_offset = 0;

my $vmaoffset = 0;

my %regs;

sub parse_x86_regs

{

my ($line) = @_;

if ($line =~ /EAX: ([0-9a-f]+) EBX: ([0-9a-f]+) ECX: ([0-9a-f]+) EDX: ([0-9a-f]+)/) {

$regs{"%eax"} = $1;

$regs{"%ebx"} = $2;

$regs{"%ecx"} = $3;

$regs{"%edx"} = $4;

}

if ($line =~ /ESI: ([0-9a-f]+) EDI: ([0-9a-f]+) EBP: ([0-9a-f]+) ESP: ([0-9a-f]+)/) {

$regs{"%esi"} = $1;

$regs{"%edi"} = $2;

$regs{"%esp"} = $4;

}

if ($line =~ /RAX: ([0-9a-f]+) RBX: ([0-9a-f]+) RCX: ([0-9a-f]+)/) {

$regs{"%eax"} = $1;

$regs{"%ebx"} = $2;

$regs{"%ecx"} = $3;

}

if ($line =~ /RDX: ([0-9a-f]+) RSI: ([0-9a-f]+) RDI: ([0-9a-f]+)/) {

$regs{"%edx"} = $1;

$regs{"%esi"} = $2;

$regs{"%edi"} = $3;

}

if ($line =~ /RBP: ([0-9a-f]+) R08: ([0-9a-f]+) R09: ([0-9a-f]+)/) {

$regs{"%r08"} = $2;

$regs{"%r09"} = $3;

}

if ($line =~ /R10: ([0-9a-f]+) R11: ([0-9a-f]+) R12: ([0-9a-f]+)/) {

$regs{"%r10"} = $1;

$regs{"%r11"} = $2;

$regs{"%r12"} = $3;

}

if ($line =~ /R13: ([0-9a-f]+) R14: ([0-9a-f]+) R15: ([0-9a-f]+)/) {

$regs{"%r13"} = $1;

$regs{"%r14"} = $2;

$regs{"%r15"} = $3;

}

}

sub reg_name

{

my ($reg) = @_;

$reg =~ s/r(.)x/e\1x/;

$reg =~ s/r(.)i/e\1i/;

$reg =~ s/r(.)p/e\1p/;

return $reg;

}

sub process_x86_regs

{

my ($line, $cntr) = @_;

my $str = "";

if (length($line) < 40) {

return ""; # not an asm istruction

}

# find the arguments to the instruction

if ($line =~ /([0-9a-zA-Z\,\%\(\)\-\+]+)$/) {

$lastword = $1;

} else {

return "";

}

# we need to find the registers that get clobbered,

# since their value is no longer relevant for previous

# instructions in the stream.

$clobber = $lastword;

# first, remove all memory operands, they're read only

$clobber =~ s/\([a-z0-9\%\,]+\)//g;

# then, remove everything before the comma, thats the read part

$clobber =~ s/.*\,//g;

# if this is the instruction that faulted, we haven't actually done

# the write yet... nothing is clobbered.

if ($cntr == 0) {

$clobber = "";

}

foreach $reg (keys(%regs)) {

my $clobberprime = reg_name($clobber);

my $lastwordprime = reg_name($lastword);

my $val = $regs{$reg};

if ($val =~ /^[0]+$/) {

$val = "0";

} else {

$val =~ s/^0*//;

}

# first check if we're clobbering this register; if we do

# we print it with a =>, and then delete its value

if ($clobber =~ /$reg/ || $clobberprime =~ /$reg/) {

if (length($val) > 0) {

$str = $str . " $reg => $val ";

}

$regs{$reg} = "";

$val = "";

}

# now check if we're reading this register

if ($lastword =~ /$reg/ || $lastwordprime =~ /$reg/) {

if (length($val) > 0) {

$str = $str . " $reg = $val ";

}

}

}

return $str;

}

while (<STDIN>) {

my $line = $_;

if ($line =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {

$target = $1;

}

if ($line =~ /RIP: 0010:\[\<([a-z0-9]+)\>\]/) {

$target = $1;

}

if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {

$function = $1;

$func_offset = $2;

}

if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\] \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {

$function = $1;

$func_offset = $2;

}

# check if it's a module

if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {

$module = $3;

}

if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\] \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {

$module = $3;

}

parse_x86_regs($line);

}

my $decodestart = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$func_offset");

my $decodestop = Math::BigInt->from_hex("0x$target") + 8192;

if ($target eq "0") {

print "No oops found!\n";

usage();

}

if ($module ne "") {

if ($modulefile eq "") {

$modulefile = `modinfo -F filename $module`;

chomp($modulefile);

}

$filename = $modulefile;

if ($filename eq "") {

print "Module .ko file for $module not found. Aborting\n";

exit;

}

# ok so we found the module, now we need to calculate the vma offset

open(FILE, $cross_compile."objdump -dS $filename |") || die "Cannot start objdump";

while (<FILE>) {

if ($_ =~ /^([0-9a-f]+) \<$function\>\:/) {

my $fu = $1;

$vmaoffset = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$fu") - Math::BigInt->from_hex("0x$func_offset");

}

}

close(FILE);

}

my $counter = 0;

my $state = 0;

my $center = -1;

my @lines;

my @reglines;

sub InRange {

my ($address, $target) = @_;

my $ad = "0x".$address;

my $ta = "0x".$target;

my $delta = Math::BigInt->from_hex($ad) - Math::BigInt->from_hex($ta);

if (($delta > -4096) && ($delta < 4096)) {

return 1;

}

return 0;

}

open(FILE, $cross_compile."objdump -dS --adjust-vma=$vmaoffset --start-address=$decodestart --stop-address=$decodestop $filename |") || die "Cannot start objdump";

while (<FILE>) {

my $line = $_;

chomp($line);

if ($state == 0) {

if ($line =~ /^([a-f0-9]+)\:/) {

if (InRange($1, $target)) {

$state = 1;

}

}

}

if ($state == 1) {

if ($line =~ /^([a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]+)\:/) {

my $val = $1;

if (!InRange($val, $target)) {

last;

}

if ($val eq $target) {

$center = $counter;

}

}

$lines[$counter] = $line;

$counter = $counter + 1;

}

}

close(FILE);

if ($counter == 0) {

print "No matching code found \n";

exit;

}

if ($center == -1) {

print "No matching code found \n";

exit;

}

my $start;

my $finish;

my $codelines = 0;

my $binarylines = 0;

$start = $center;

while ($start > 1) {

$start = $start - 1;

my $line = $lines[$start];

if ($line =~ /^([a-f0-9]+)\:/) {

$binarylines = $binarylines + 1;

} else {

$codelines = $codelines + 1;

}

if ($codelines > 10) {

last;

}

if ($binarylines > 20) {

last;

}

}

$finish = $center;

$codelines = 0;

$binarylines = 0;

while ($finish < $counter) {

$finish = $finish + 1;

my $line = $lines[$finish];

if ($line =~ /^([a-f0-9]+)\:/) {

$binarylines = $binarylines + 1;

} else {

$codelines = $codelines + 1;

}

if ($codelines > 10) {

last;

}

if ($binarylines > 20) {

last;

}

}

my $i;

$i = $center;

while ($i >= $start) {

$reglines[$i] = process_x86_regs($lines[$i], $center - $i);

$i = $i - 1;

}

$i = $start;

while ($i < $finish) {

my $line;

if ($i == $center) {

$line = "*$lines[$i] ";

} else {

$line = " $lines[$i] ";

}

print $line;

if (defined($reglines[$i]) && length($reglines[$i]) > 0) {

my $c = 60 - length($line);

while ($c > 0) { print " "; $c = $c - 1; };

print "| $reglines[$i]";

}

if ($i == $center) {

print "<--- faulting instruction";

}

print "\n";

$i = $i +1;

}

sub usage {

print <<EOT;

exit;

}