OpenSSH GSoC Project

Pavel Labath pavelo at centrum.sk
Tue Mar 24 08:05:23 EST 2009


Hi all,

I too would like to apply for GSoC scholarship and work on sftp.

I'm not sure if i should contact djm directly (you say he's swamped with
 emails, so i guess people are talking to him privately), but I thought
I'd write here.

So, what are the features we want a polished sftp to have? The only
thing mentioned so far is the recursive up/down load, which looks more
like a thing for a two day hackfest than a all-summer-long $4.5k
operation. Features i would consider useful are:
- tab completion (both commands and filenames) - very useful, not difficult
- transfer resume (thanks Iain Morgan, I almost forgot) - very useful,
not difficult
- background transfer (possibly threads, or just fancy select() calls) -
useful, not very difficult
- server to server transfer (the data will have to go through the local
machine - unless we want to add an extension for a pure server2server
xfer, but that is probably not a good idea, security-wise) - I'm not
sure about the usefulness, it may be easier to just log onto one machine
(assuming you can do that) and initiate the transfer from there. But,
scp can do that so I guess it should be done. the client doesn't use
global variables, so it shouldn't be that difficult to do.

Also, I was wondering, did you plan to do any modifications to the
server program?
- the append thing was mentioned already, it could be useful (piping
logs through sftp? maybe, i don't know)
- I noticed the spec mentions ACL:s and mandatory/advisory locks. Do we
want to support that? I'm not sure how portable those are, but it may be
possible to do them.
- If I understood the code correctly, server does buffer network
messages. But it may be better, given today's fast networks, to also do
parallel disk reads and writes, especially if they are on different disks.

Am I on the right track here? What did you have in mind for this
project? I'd appreciate any feedback.

PS: @Peter Stuge
What did you mean by the "internal structure in the sftp client
program"? Could you elaborate on that? I found the code very easy to
read and self-explanatory, even without comments. Sure, it doesn't have
all the bells and whistles, but that's what we're here to change. ;)

Thanks,
-- 
Pavel Labath


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