rsync proxy

[Matt McCutchen]

On Wed, 2009-08-26 at 22:12 +1200, Nathan Ward wrote:
> I'm trying to write an rsync 'proxy' of sorts. The plan is that my  
> code runs on two machines (one 'client' and one 'server') and each  
> piece of code executes a copy of rsync, and copies move in one  
> direction (server -> client).
> 
> I have been able to run rsync on the 'server' end by calling it with -- 
> server --sender and so on. On the client end I have rsync call my code  
> with -e "my_code", however I am trying to make it so that on the  
> 'client' end, I can have my code call rsync, instead of the other way  
> around.
> 
> When I call --server on the 'client' end, rsync seems to handshake OK,  
> but I get buffer overflow errors:
> <snip>
> ERROR: buffer overflow in recv_rules [sender]
> rsync error: error allocating core memory buffers (code 22) at / 
> SourceCache/rsync/rsync-35.2/rsync/util.c(121) [sender=2.6.9]
> </snip>
> 
> The above is sent from the 'server' to the 'client'.
> 
> Before I go delving in to the code, is --server supposed to be used in  
> this way? I am basically attempting to join two rsync processes both  
> running --server, but only one running --sender.

No, that will not work.  The rsync protocol requires one client and one
server.

See https://bugzilla.samba.org/show_bug.cgi?id=5220 for some ideas on
how to call an rsync client from your code and get it to use your
existing connection.

> The background here is I'm writing a backup tool and need to do a few  
> more things than rsync can do alone, but there's no point replicating  
> the stuff that rsync *can* do. I also don't want to use the rsync  
> daemon, nor do I want to have a user account that is remotely  
> accessible in order to get rsync over ssh going. Yes I know there are  
> solutions for parts of this, but I want to write this tool all the same.

Indeed, there may be better solutions for the whole thing if you explain
your use case further.

-- 
Matt