Get the serial number of the volume udf cd / dvd disk? - linux

Question

I'm writing a program in linux which counts the serial number (xxxx-xxxx) of the volume of the CD in Windows 7. My program correctly determines the serial number of the volume on disks with the filesystems iso9660 and joilet. But how to define a disk volume sniffer with a file system udf? Can someone tell me ....
ps if anyone does not understand I'm talking about the serial number of this kind https://extra-torrent.jimdo.com/2016/01/23/hard-disk-volume-serial-number-change/
#include <QCoreApplication>
#include <stdio.h>
#include <sys/ioctl.h>
#include <linux/cdrom.h>
#include <string.h>
#include <szi/szimac.h>
#include <qfile.h>
#include <iostream>
#include <QDir>
#include <unistd.h>
#define SEC_SIZE 2048
#define VD_N 16
#define VD_TYPE_SUPP 2
#define VD_TYPE_END 255
#define ESC_IDX 88
#define ESC_LEN 3
#define ESC_UCS2L1 "%/#"
#define ESC_UCS2L2 "%/C"
#define ESC_UCS2L3 "%/E"
using namespace std;
int cdid(unsigned char pvd[SEC_SIZE])
{
unsigned char part[4] = {0};
int i;
for(i = 0; i < SEC_SIZE; i += 4)
{
part[3] += pvd[i + 0];
part[2] += pvd[i + 1];
part[1] += pvd[i + 2];
part[0] += pvd[i + 3];
}
return (part[3] << 24) + (part[2] << 16) + (part[1] << 8) + part[0];
}
int main(int argc, char *argv[])
{
FILE *in;
unsigned char buf[SEC_SIZE];
struct cdrom_multisession msinfo;
long session_start;
int id;
QString home=QString(getenv("HOME"))+QString("/chteniestorm");
QFile file(home);
ustr="/dev/sr0";
in = fopen(ustr.toLocal8Bit().data(), "rb");
if(in == NULL)
{
if (file.open(QIODevice::WriteOnly))
{
file.write("sernom=1");
file.close();
}
cout<<"netdiska"<<endl;
return 0;
}
/* Get session info */
msinfo.addr_format = CDROM_LBA;
if(ioctl(fileno(in), CDROMMULTISESSION, &msinfo) != 0)
{
fprintf(stderr, "WARNING: Can't get multisession info\n");
perror(NULL);
session_start = 0;
}
else
{
session_start = msinfo.addr.lba;
}
fseek(in, 0, SEEK_SET); //to the begining
/* Seek to primary volume descriptor */
if(fseek(in, (session_start + VD_N) * SEC_SIZE, SEEK_SET) != 0)
{
if (file.open(QIODevice::WriteOnly))
{
file.write("sernom=2");
file.close();
}
fclose(in);
return 0;
}
/* Read descriptor */
if(fread(buf, 1, SEC_SIZE, in) != SEC_SIZE)
{
if (file.open(QIODevice::WriteOnly))
{
file.write("sernom=3");
file.close();
}
fclose(in);
return 0;
}
/* Caclculate disc id */
id = cdid(buf);
/* Search for Joliet extension */
while(buf[0] != VD_TYPE_END)
{
/* Read descriptor */
if(fread(buf, 1, SEC_SIZE, in) != SEC_SIZE)
{
perror(NULL);
return 0;
}
if(buf[0] == VD_TYPE_SUPP
&& (memcmp(buf + ESC_IDX, ESC_UCS2L1, ESC_LEN) == 0
|| memcmp(buf + ESC_IDX, ESC_UCS2L2, ESC_LEN) == 0
|| memcmp(buf + ESC_IDX, ESC_UCS2L3, ESC_LEN) == 0)
)
{
/* Joliet found */
id = cdid(buf);
}
}
fclose(in);
}

Answer 1

It looks like this question was asked on more places [1], [2], [3], [4] but nowhere was answered yet. So I will do it here.
In some of those posts people decoded serial number generation algorithm. It is just checksum which you already have found and put into your cdid() function. Same checksum algorithm is used for both ISO9660 and UDF filesystems on Windows. You have already figured out from which ISO9660 structures is that checksum calculated.
So your question remain just for UDF filesystem. For UDF filesystem on Windows that checksum is calculated from the 512 bytes long File Set Descriptor (FSD) structure. I would suggest you to read OSTA UDF specification how to locale that FSD on UDF disc.
Basically for plain UDF which do not use Virtual Allocation Table (VAT), Sparing Table or Metadata Partition, location of the FSD is stored in Logical Volume Descriptor (LVD) structure, in field LogicalVolumeContentsUse (it is of type long_ad). LVD is stored in the Volume Descriptor Sequence (VDS). VDS's location is stored in Anchor Volume Descriptor Pointer (AVDP), in field MainVolumeDescriptorSequenceExtent. AVDP itself is located at sector 256 of medium. Optical media have sector size 2048 bytes and common hard disk 512 bytes.
For UDF with VAT (e.g. on CD-R/DVD-R/BD-R), Sparing Table (e.g. on CD-RW/DVD-RW) or Metadata Partition (e.g. on Blu-ray), it is much more complicated. You need to look into Virtual, Sparable or Metadata Partition to figure out how to translate logical location of the FSD to physical location of media.
In udftools project starting with version 2.0, there is a new tool udfinfo which provides various information about UDF filesystem. It shows also that Windows specific Volume Serial Number from your question under winserialnum key. Note that udfinfo cannot read FSD from UDF filesystem with VAT or Metadata yet.