On 04/11/2011 03:28 PM, Venkateswararao Jujjuri wrote:
On 04/11/2011 06:42 AM, Rob Landley wrote:
Right now, there's no decent userspace server for the 9p filesystem that
I can find. (In part because the 9P2000.L spec is an undocumented work
in progress.)
This statement is true for 9P2000.L protocol;
According to my research on the topic, anyway:
http://landley.livejournal.com/48698.html
But for older protocols we have standalone servers like spfs/npfs.
http://sourceforge.net/projects/npfs/
This would be the one that has no documentation or web page, builds
without ./configure, and has no way to specify which directory to export
but apparently can ONLY export / on the host?
http://9p.cat-v.org/implementations
I looked at those. Several are unfinished libraries, some also only
export / and treat the whole "restrict what you're exporting to a
subdir" problem as inherently unsolvable (readlink -f), the main one
everybody seems to test with is the Inferno equivalent of usermode
Linux, there's a python server that refuses to run without some third
party encryption/authentication library that it never OCCURRED to their
developers you might want t disable...
I also tracked down more like http://code.google.com/p/diod/ (and
emailed its author for a while: that project is stalled due to his
desire to rewrite large chunks of it, and a lack of time).
I also subscribed to v9fs-users, which is not the world's highest
traffic list:
http://sourceforge.net/mailarchive/forum.php?forum_name=v9fs-users
The only up-to-date server seems to be virtfs in qemu, which has no TCP
transport layer.
Are there any plans to:
A) Add a TCP transport layer so we can test with something we can
intercept/examine/log/redirect with netcat and such?
No plans as of now; I know folks in the Latchesar Ionkov attempted char
dev transport.
NFS works over TCP. Samba works over TCP. But not p9. Is there some
reason to go out of the way to avoid it?
Not sure the latest though.
http://sourceforge.net/mailarchive/forum.php?thread_name=AANLkTim4eZttAmaNQfOuM1h7cmLvO-osckHNunMvG7o%2B%40mail.gmail.com&forum_name=v9fs-developer
Ah, if I want information about userspace servers I should subscribe to
v9fs-developer instead of v9fs-user, because it has no users yet. Got it.
B) Break the 9p server out so it could be built as a standalone
userspace program?
No plans yet..and I think this is a bigger discussion.
If this filesystem is to become more than an academic exercise, it needs
a server that can export a specific directory.
Being part of QEMU brings few implicit advantages like simplicity in
sharing, security
and performance advantage. I think taking it out can have its own merits.
I wasn't suggesting removing it from QEMU. Having it in QEMU is great,
the code is written and works, it's useful as-is, and half the _idea_ of
this is that it's simpler than samba or NFS (which is damning with faint
praise, I know).
In theory, all the actual protocol encoding and decoding (and doing the
read/write/stat stuff on the host) is a single C file, correct? Right
now there isn't any reference implementation of that server-side code,
but there is a working example of it. Virtfs is a working example, just
not hooked up to a particularly useful transport. (If it had a TCP
transport I could route it back out through a tap interface or -redir
port and use qemu as a test server... but it doesn't. As far as I can
tell, virtio is intentionally the _least_ flexible mechanism for that
sort of thing. Although maybe there's docs on this and I've just missed
them...)
Rob