rsync - Sep 2002 - Feature request: Sync Mac OS resource forks and metadata on Mac OS X

I have a feature request for rsync. I tried posting it to the 
FAQ-o-matic, but that system didn't seem to be accepting new 
questions. I hope this is an okay list for the request--apologies if 
it's misdirected.

Mac OS X provides support for the Mac file system resource forks and 
mac specific metadata (e.g., creator and file type). Most Unix 
applications ignore this information, but it is accessible. It would 
be great if rsync between two Mac OS X machines could sync this 
information as well as the usual Unix file contents and unix metadata.

I plan to take a look at the source, but I don't have high hopes of 
being able to create a robust patch. Hopefully this will be easy for 
someone who knows Mac OS X.
-- 

Kevin Crowston
Syracuse University			    Phone:  +1 (315) 443-1676
School of Information Studies		    Fax:    +1 (315) 443-5806
4-206 Centre for Science and Technology	    EMail:  crowston@syr.edu
Syracuse, NY   13244-4100   USA		    Web:    http://crowston.syr.edu/

On Tuesday, Sep 17, 2002, at 15:31 US/Eastern, Kevin Crowston wrote:
> I have a feature request for rsync. I tried posting it to the 
> FAQ-o-matic, but that system didn't seem to be accepting new 
> questions. I hope this is an okay list for the request--apologies if 
> it's misdirected.
>
> Mac OS X provides support for the Mac file system resource forks and 
> mac specific metadata (e.g., creator and file type). Most Unix 
> applications ignore this information, but it is accessible. It would 
> be great if rsync between two Mac OS X machines could sync this 
> information as well as the usual Unix file contents and unix metadata.
>
> I plan to take a look at the source, but I don't have high hopes of 
> being able to create a robust patch. Hopefully this will be easy for 
> someone who knows Mac OS X.
	It's already done: http://www.macosxlabs.org/rsyncx/rsyncx.html

	The underlying CLI tool is an HFS+ resource aware version of rsync 
2.5.5.

	I've asked this before on this list, and never received a response... 
what are the barriers to getting this support added to the main rsync 
tree as part of the MacOS X configuration?  Having this in the maintree 
would be highly useful to MacOS X users, instead of having to have to 
continually patch the rsync tree with the HFS+ patch.

Jason Smith <smithja@cs.unc.edu> wrote:
> > Mac OS X provides support for the Mac file system resource forks and 
> > mac specific metadata (e.g., creator and file type). Most Unix 
> > applications ignore this information, but it is accessible. It would 
> > be great if rsync between two Mac OS X machines could sync this 
> > information as well as the usual Unix file contents and unix metadata.
> 
> 	It's already done: http://www.macosxlabs.org/rsyncx/rsyncx.html
> 
> 	The underlying CLI tool is an HFS+ resource aware version of rsync 
> 2.5.5.
> 
> 	I've asked this before on this list, and never received a response... 
> what are the barriers to getting this support added to the main rsync 
> tree as part of the MacOS X configuration?  Having this in the maintree 
> would be highly useful to MacOS X users, instead of having to have to 
> continually patch the rsync tree with the HFS+ patch.
Linux too supports  HFS with data forks and  resource forks and Finder
infos.  And three different ways at that.

Try either: mount -t hfs -o 'fork=cap'      ...
            mount -t hfs -o 'fork=double'   ...
        or  mount -t hfs -o 'fork=netatalk' ...

Check '/usr/src/linux/fs/hfs/HFS.txt'.

Well, actually, what's in as  support is just some convention, used by
various user-level software, about the  naming of files and storage of
forks  on  a unix  file  system.   See  for example  mkisofs(8)  which
supports the following conventions:

       CAP AUFS format
       AppleDouble/Netatalk
       AppleSingle
       Helios EtherShare
       IPT UShare
       MacBinary                            
       Apple PC Exchange
       SGI/XINET                            
       Thursby Software Systems DAVE        
       Services for Macintosh               (NT Servers)

What's remarkable is that these convention are used on a full range of
systems where rsync can run.


So, I  would suggest that  rsync (main distribution) supports  them as
well and that  it uses the "local" convetion at each  end of the pipe.


So,  if  rsync'ing  a volume  where  HFS  forks  are stored  with  the
"Services  for Macintosh"  convetion of  the NT  servers, to  a volume
where HFS  forks are stored in  the MacBinary convention,  that such a
transformation be  done.  Most often  it'll just mean change  the file
name,  but  it  can also  mean  mixing  some  forks  into one  or  two
files. (AppleDouble stores the data fork in one file, and the resource
fork  and  Finder  info   into  another  (hence  double  file),  while
AppleSingle stores  everything into one  file, but CAP stores  each in
its own file (3 in total)).

Of course, MacOSX which is able  to store into a true HFS volume would
store into true forked files.


-- 
__Pascal_Bourguignon__                   http://www.informatimago.com/
----------------------------------------------------------------------
 The name is Baud,...... James Baud.