mtree(8) keyword clarification: "device"

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Hi lists,

I am actually working on making libarchive's mtree format and our 
NetBSD's mtree(8) interchangeable, but I am facing a documentation issue 
that dates back /a priori/ to 2001, and that concerns the "device" 
keyword. Copy paste from NetBSD's mtree(8):


[...]
     device          The device number to use for block or char file 
types.
                     The argument must be one of the following forms:

                     format,major,minor
                           A device with major and minor fields, for an
                           operating system specified with format.  See 
below
                           for valid formats.

                     format,major,unit,subunit
                           A device with major, unit, and subunit 
fields, for
                           an operating system specified with format.
                           (Currently this is only supported by the 
bsdos
                           format.)

                     number
                           Opaque number (as stored on the file 
system).

                     The following values for format are recognized: 
native,
                     386bsd, 4bsd, bsdos, freebsd, hpux, isc, linux, 
netbsd,
                     osf1, sco, solaris, sunos, svr3, svr4, and ultrix.


The actual implementation in C never goes beyond the point of printing 
(long long)st_rdev from stat(2) in %llx, and use it "as-is" for 
mknod(8).

Libarchive does it differently and log it as 
"device=native,<major>,<minor>" format.

Questions arise:
- what was the intent of this keyword, especially the format part? 
mtree(8) was expected to receive some kind of "-k device=netbsd" 
parameter? Or does it only specify the argument of the resulting mtree 
evaluation?
- the actual code in libarchive does not follow NetBSD's format, it 
prints "device" by default as "native,<major>,<minor>". Would it be 
acceptable for libarchive to accept raw, opaque number with the 
convention that it starts with "Ox"?

Thanking you in advance for your clarifications

Cheers,

--
Jean-Yves Migeon