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List:       xine-codec-devel
Subject:    [codec-devel] Determening datatypes
From:       Benjamin Larsson <banan () student ! ltu ! se>
Date:       2004-08-14 10:53:34
Message-ID: 411DEF2E.2060003 () student ! luth ! se
[Download RAW message or body]

Hi, I've written a perl program that can extract tables out of binarys.

Try theise examples to get hold of what it can do:

./tableextractor.pl -f ~/RealPlayer7/Codecs/dspr.so.6.0 test uchar 10
./tableextractor.pl -f ~/RealPlayer7/Codecs/dspr.so.6.0 dico1_isf test 10
./tableextractor.pl -f ~/RealPlayer7/Codecs/dspr.so.6.0 dico1_isf uchar 10

Now to the question, how do you get the correct datatype for a table ? 
Is there some smart way to get that information or do you check the 
assembly how it accesses and manipulates the data ?

MvH
Benjamin Larsson

["tableextractor.pl" (application/x-perl)]

#!/usr/bin/perl 

# Init av variabler
sub callsource;
sub padding;


#Argument parser

if (@ARGV){
#  print "@ARGV\n";
  if ($ARGV[0] eq "-f"){
    $FILE1 = $ARGV[1];
    $tablename = $ARGV[2];
    $vartype = $ARGV[3];
    chomp($vartype);
    $cols = $ARGV[4];
  }
}
else{
  print "Usage:\n";
  print "./tableextractor.pl [command] binary function vartype cols\n";
  print "-f input datafile\n";
  exit;
}

#Check what type the table is supposed to be
@vartypelist = ("ascii","char","uchar","short","ushort","int","uint","long","ulong","netshort","netlong","float","dfloat","hex","nethex");
 @unpacklist = ("A","c","C","s","S","i","I","l","L","n","N","f","d","h","H");

$typenr = 100;
for ($nptr=0;$nptr < $#vartypelist +1;$nptr++){
	if ($vartype eq $vartypelist[$nptr]) {
		$typenr = $nptr;
	}
}

if ($typenr == 100) {
	print "Vartype is not of correct type. Try one of theise:\n";
	foreach $rad (@vartypelist) {
		print "$rad\n";
	}
	exit;
}


# File IO
# get DYNAMIC SYMBOL TABLE

@fresource = `objdump -T $FILE1`;
$dsym = 0;

@tabaddress = 0;
@tabname = 0;
@tablength = 0;
$tabindex = 1;

#parse out the tables
foreach $rad (@fresource) {
	if ($dsym){
		$type = (substr $rad,17,5);
		if ($type eq ".data") {
			$address = (substr $rad,0,8);
			$address =~ m/0*/;              #get rid of starting 0's
			$address = $';
			$tablelength = (substr $rad,23,8);
			$tablelength =~ m/0*/;
			$tablelength = $';
			$tablen = (substr $rad,32);
			chomp($tablen);
			
			#save the list
			$tabaddress[$tabindex] = hex($address);
			$tabname[$tabindex] = $tablen;
			$tablength[$tabindex] = hex($tablelength);
			$tabindex++;
			#print "$address $type $tablelength $tablename\n";
		}
	}
	if ($rad =~ m/DYNAMIC/) {
		$dsym = 1;
	}
}

$nameptr = 0;
$nptr = 0;
for ($nptr=1;$nptr < $#tabname +1;$nptr++){
	if ($tabname[$nptr] eq $tablename) {
		$nameptr = $nptr;	
	}
}

if ($nameptr == 0) {
	print "Table does not exist or is misspelled. Try one of theise:\n";
	for ($nptr=1;$nptr < $#tabname +1;$nptr++){
		print "$tabname[$nptr]\n";
	}
	exit;
}


#Get .data offset

$doffset = 0;
@offsets = `readelf -S $FILE1`;
foreach $rad (@offsets) {
	if ($rad=~ m/ \.data/) {
		$dataaddress = (substr $rad,41,8);
		$dataaddress =~ m/0*/;
		$dataaddress = $';
		$dataoffset = (substr $rad,50,6);
		$dataoffset =~ m/0*/;
		$dataoffset = $';
		#print "$dataaddress $dataoffset|\n";
		$doffset = hex($dataaddress) - hex($dataoffset);
	}
}

#Calculate real address for table
$seekaddress = $tabaddress[$nameptr] - $doffset;

#Time to access the file for data

open(BINFILE, $FILE1) or die "can't open $FILE1: $!";
seek(BINFILE, $seekaddress, 0) or die "seek:$!";
#seek(BINFILE,hex(c61),0) or die "seek:$!";
read(BINFILE, $BUFFER, $tablength[$nameptr]);

@fields = unpack("$unpacklist[$typenr]*",$BUFFER);



#Print out everything in a nice form

$colcounter = 0;
$tablesi = $#fields+1;
print "/**\n";
print " * Table $tablename taken from file $FILE1.\n";
print " */\n\n";
print "static const $vartypelist[$typenr] $tablename\[$tablesi\] = {\n";
foreach $rad (@fields) {
	if ($colcounter == $cols) {
		print "\n";
		$colcounter = 0;
	}
	print "$rad,";
	$colcounter ++;
}

print "\n};\n";

close(BINFILE);


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