Re: [Libcdio-devel] Joliet bug?

[Burkhard Plaum]

Hi,

R. Bernstein wrote:
> I just had a chance to look at this Joliet problem is in more detail.
>
> First, I'd like to summarize to make sure I understand this correctly.
>
> The problem observed is that the routine ucs2be_to_locale() in
> iso9660_fs.c expects a stream of bytes that is UCS-BE16 (Universal
> Character Set Big-Endian 16-bit), but is probably getting something
> that is not that when it is called via
>
>     iso9660_ifs_get_preparer_id(), 
>     iso9660_ifs_get_publisher_id(),
>     iso9660_ifs_get_volumeset_id(), or 
>     iso9660_ifs_get_application_id().
>
> However things are okay when ucs2be_to_locale() is called via 
>     iso9660_ifs_get_system_id();
>     iso9660_ifs_get_volume_id();

Yes. You can easily reproduce it by hexdumping the string passed to
ucs2be_to_locale(). If you don't have a hexdump routine nearby, take this
(set last arg to 16 to get a linebreak each 16 bytes):

void bgav_hexdump(uint8_t * data, int len, int linebreak)
  {
  int i;
  int bytes_written = 0;
  int imax;

  while(bytes_written < len)
    {
    imax = (bytes_written + linebreak > len) ? len - bytes_written : linebreak;
    for(i = 0; i < imax; i++)
      fprintf(stderr, "%02x ", data[bytes_written + i]);
    for(i = imax; i < linebreak; i++)
      fprintf(stderr, "   ");
    for(i = 0; i < imax; i++)
      {
      if(!(data[bytes_written + i] & 0x80) && (data[bytes_written + i] >= 32))
        fprintf(stderr, "%c", data[bytes_written + i]);
      else
        fprintf(stderr, ".");
      }
    bytes_written += imax;
    fprintf(stderr, "\n");
    }
  }

When ACSII characters (< 128) are printed in UCS-BE16, the first byte of each 
character
must be 0x00.

> If this is correct, at present I'm not sure yet whether the problem
> has to do with the way the ISO 9660 was created or (more likely)
> libcdio's interpretation. And to fix the libcdio's interpretation, I
> guess I need to understand in which way libcdio messed up.

Ok, I tried just with one CD created by k3b. Maybe some CDs made by
other software can enlighten the situation.

> For the ISO 9660 standard, I've been using the European draft ECMA 119
> which is freely available at
> http://www.ecma-international.org/publications/standards/Ecma-119.htm
>
> However the relevant portion is probably this below (where BP refers to the 
> byte offset):

That's the iso9660 spec, right? I think the bug happens for Joliet only.
All calls to ucs2be_to_locale() are enclosed by

if(p_iso->i_joliet_level) { /* ... */ }

so I guess it shows up only when Joliet structures are present.
The observed behaviour is, that ucs2be_to_locale() fails in the mentioned cases
and the iso9660_*_get_*() functions return other strings (from plain iso9660?),
which are, indeed, correct.

Burkhard