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Re: Announcing xorriso-0.3.6



Hi,

Joerg Schilling wrote:
> Neither ISO-9660 not Rock Ridge support ACLs or xattrs.

True. But SUSP allows to define own extension field
types in the System Use Area. See
  ftp://ftp.ymi.com/pub/rockridge/susp112.ps

I did that in form of AAIP. See
  http://www.libburnia-project.org/wiki/AAIP

mkisofs is invited to join that protocol.
Maybe after some due time, kernels will begin
to interpret it and show ACL and userspace
xattr.
For now, one needs keen extraction software,
like xorriso, in order to retrieve the info.

-------------------------------------------------------
For bystanders:

- ISO 9660 / ECMA-119 defines directory records which
  contain a filename, a pointer to its data content,
  some other attributes, and a System Use Area for
  additional (small) payload.
  The meaning of that payload is not specified.

- System Use Sharing Protocol (SUSP) defines a packet
  format for that area, the System Use Fields. It also
  defines some field types for announcing the presence
  of extensions and for enlarging the payload space up
  to the maximum size of an ISO image: 8 TB.
  SUSP states that a reader program shall ignore any
  fields of unknown type.
  This rule is nearly 20 years old and even obeyed
  by Solaris hsfs which seems not to have been adapted
  to the newer specs since about 15 years.

- Rock Ridge Interchange Protocol (RRIP) is such an
  extension. It adds the file attributes and file types
  as expected by a POSIX (or rather X/Open) system.

- Arbitrary Attribute Interchange Protocol (AAIP) is
  now another extension which is intended as companion
  of RRIP.
  Its field type AA allows to store a nearly arbitrary
  number of value=name pairs. This is used by libisofs
  to store ACL, xattr out of the "user" namespace,
  and own management information in an "isofs" namespace.
  E.g. "isofs.di" which records the original device
  number and inode number of a file, allowing fast
  incremental backup decisions.

---------------------------------------------------------

Have a nice day :)

Thomas
 


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