[9fans] mount 9P on Linux and FreeBSD via FUSE

[9fans] mount 9P on Linux and FreeBSD via FUSE

[Russ Cox]

Various changes to p9p over the weekend;
see http://swtch.com/usr/local/plan9/CHANGES.

The changes center around a new program called 9pfuse
(inspired by Christoph Lohmann's program of the same name)
that mounts 9P servers on Linux and FreeBSD via FUSE.
9pfuse uses the raw FUSE message format instead of using
the high-level library interface, which actually hides some
details important to a faithful translation.

The net result is that I can do:

	x40=; 9 mount `namespace`/acme /mnt/acme
	x40=; ls /mnt/acme
	309  355  356  acme  cons  consctl  draw  editout  index  label  new
	x40=; cat /mnt/acme/356/body
	Hello, FUSE!
	x40=; unmount /mnt/acme
	x40=;

Thanks to Lou Kamenov for working through some FreeBSD
bugs.  If you want to use 9pfuse on FreeBSD you'll need the
very latest FUSE implementation (this morning's), which
fixes some protocol errors on the part of the kernel module.

And thanks to Christoph Lohmann for writing the other 9pfuse.

Russ

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

> 	x40=; 9 mount `namespace`/acme /mnt/acme
I get a
	rc: /usr/local/plan9/bin/mount:12: token '=': syntax error
on Linux.

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[andrey mirtchovski]

i think you must omit "x40=;" as that is russ' prompt. either that or use 9term.

On 7/27/06, csant <csant@csant.info> wrote:
> >       x40=; 9 mount `namespace`/acme /mnt/acme
> I get a
>         rc: /usr/local/plan9/bin/mount:12: token '=': syntax error
> on Linux.
>

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

> i think you must omit "x40=;" as that is russ' prompt. either that or  
> use 9term.

Yes, yes - I am omitting the prompt :)
Still I get a syntax error I cannot make any sense of... (the syntax is  
right, isn't it?)
Haven't tried 9term yet, but last time I did it killed my X server - need  
to investigate on that - so I'd like to postpone that try.

> On 7/27/06, csant <csant@csant.info> wrote:
>> >       x40=; 9 mount `namespace`/acme /mnt/acme
>> I get a
>>         rc: /usr/local/plan9/bin/mount:12: token '=': syntax error
>> on Linux.
>>
>



-- 
[Quote]
I have measured out my life with coffee spoons;
~~~ T.S. Eliot

Re: Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Anthony Sorace]

the new script 'mount' relies on a recent change to rc to allow
unquoted ='s in argument lists. i suspect you're running an old rc.
either update rc or modify the mount script to quote your ='s.

Re: Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Russ Cox]

> the new script 'mount' relies on a recent change to rc to allow
> unquoted ='s in argument lists. i suspect you're running an old rc.
> either update rc or modify the mount script to quote your ='s.

That change isn't quite correct, either, but I haven't
gotten to fixing it yet.  (It turns "echo a = b" into "echo a=b".)

I fixed the mount script to quote properly.

Russ

Re: Re: Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[andrey mirtchovski]

i'm trying this on fedora core 5 (intel's core duo) but seem to be
missing a 'fusermount' program. i'm trying to find it now and when i
do i'll let you know (so far i'm only finding advisories and bug
reports about it).

Re: Re: Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

> i'm trying this on fedora core 5 (intel's core duo) but seem to be
> missing a 'fusermount' program. i'm trying to find it now and when i
> do i'll let you know (so far i'm only finding advisories and bug
> reports about it).

It's part of FUSE, isn't it? http://fuse.sourceforge.net/

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[andrey mirtchovski]

>
> It's part of FUSE, isn't it? http://fuse.sourceforge.net/

i thought that was already installed, after all the fuse module is :)

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

>> It's part of FUSE, isn't it? http://fuse.sourceforge.net/
>
> i thought that was already installed, after all the fuse module is :)

The fuse module is a kernel module, and part of the kernel tree, the
userland tools are not.

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[andrey mirtchovski]

> The fuse module is a kernel module, and part of the kernel tree,
> the userland tools are not.

i kept thinking that all i need to do is mount :)

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

>> The fuse module is a kernel module, and part of the kernel tree, the
>> userland tools are not.
>
> i kept thinking that all i need to do is mount :)

AFAIK you need some filesystem specific mount tool, and umount (requires
root privileges) or fusermount (no root privileges) to unmount. Not
actually sure if you can mount simply with mount.

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Charles Forsyth]

> i kept thinking that all i need to do is mount :)

just keep reminding yourself that you're in The Land that Time Forgot

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[andrey mirtchovski]

trying on the aforementioned intel with the aforementioned linux
distribution i get 'permission denied' errors every time i try to
access the mounted directory.

turns out that fuse sends out an extra flag, O_LARGEFILE=0x8000, which
9pfuse.c thinks it has masked. it also turns out that the two programs
involved differ over what O_LARGEFILE should be defined as:
O_LARGEFILE is 0 for 9pfuse.c (actually it was defined at compile time
as it couldn't find it in the include files)

bits/fcntl.h has the following to say (after a few spelling errors):

#ifdef __USE_LARGEFILE64
# if __WORDSIZE == 64
#  define O_LARGEFILE   0
# else
#  define O_LARGEFILE   0100000
# endif
#endif

this particular standard installation has __USE_LARGEFILE64 undefined,
and i assume that the one which the kernel was compiled on did.

i suppose i should recompile the fuse module, or fusermount or
something else... i feel a sacrifice is required.

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Skip Tavakkolian]

> i suppose i should recompile the fuse module, or fusermount or
> something else... i feel a sacrifice is required.

i saw in a movie where they used a bucket of kfc chicken (original
recipe i think) instead of a live chicken. worth a try.

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Russ Cox]

"Fixed."

tux=; cvs diff -u -r1.7 main.c
Index: main.c
===================================================================
RCS file: /home/am3/rsc/cvsroot/plan9/src/cmd/9pfuse/main.c,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -r1.7 -r1.8
--- main.c	27 Jul 2006 05:14:16 -0000	1.7
+++ main.c	27 Jul 2006 22:36:00 -0000	1.8
@@ -23,8 +23,12 @@
 #define O_DIRECTORY 0
 #endif
 #ifndef O_LARGEFILE
+#if defined(__linux__)
+#define O_LARGEFILE 0100000  /* Sigh */
+#else
 #define O_LARGEFILE 0
 #endif
+#endif


 int debug;
tux=;


On 7/27/06, andrey mirtchovski <mirtchovski@gmail.com> wrote:
> trying on the aforementioned intel with the aforementioned linux
> distribution i get 'permission denied' errors every time i try to
> access the mounted directory.
>
> turns out that fuse sends out an extra flag, O_LARGEFILE=0x8000, which
> 9pfuse.c thinks it has masked. it also turns out that the two programs
> involved differ over what O_LARGEFILE should be defined as:
> O_LARGEFILE is 0 for 9pfuse.c (actually it was defined at compile time
> as it couldn't find it in the include files)
>
> bits/fcntl.h has the following to say (after a few spelling errors):
>
> #ifdef __USE_LARGEFILE64
> # if __WORDSIZE == 64
> #  define O_LARGEFILE   0
> # else
> #  define O_LARGEFILE   0100000
> # endif
> #endif
>
> this particular standard installation has __USE_LARGEFILE64 undefined,
> and i assume that the one which the kernel was compiled on did.
>
> i suppose i should recompile the fuse module, or fusermount or
> something else... i feel a sacrifice is required.
>
>

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[geoff]

I had 9P mounting working but the v9fs (9P) module has vanished from
my Linux machine.  As root, I invoked the equivalent in C of

	mount -t 9P -o proto=fd,name=$LOGNAME,rfdno=%d,wfdno=%d '' /n/remote

where %d is the file descriptor to communicate with the 9P server.
The more common usage is

	mount -t 9P -o name=geoff 10.240.55.178 /n/remote

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Russ Cox]

9 mount (http://swtch.com/usr/local/plan9/bin/mount) does try 9P first.
Not everyone has v9fs though (e.g., Linux 2.4).

Russ

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[erik quanstrom]

i use this in my /etc/fstab

/tmp/ns.quanstro.:0/acme	/home/quanstro/9/acme	9P	uid=1000,user,name=quanstro,proto=unix,noauto	0 0
/tmp/ns.quanstro.:0/upasfs	/home/quanstro/9/upasfs	9P	uid=1000,user,name=quanstro,proto=unix,noauto	0 0
/tmp/ns.quanstro.:0/sources	/home/quanstro/9/sources	9P	uid=1000,user,name=quanstro,proto=unix,noauto	0 0
/tmp/ns.quanstro.:0/tapefs	/home/quanstro/9/tapefs	9P	uid=1000,user,name=quanstro,proto=unix,noauto	0 0
/tmp/ns.quanstro.:0/dns	/home/quanstro/9/dns	9P	uid=1000,user,name=quanstro,proto=unix,noauto	0 0

this allows me (without becoming root or having v9fs) to
	; mount $home/9/acme
assuming that acme is running and my current namespace is the default.

- erik

On Thu Jul 27 17:58:11 CDT 2006, geoff@collyer.net wrote:
> I had 9P mounting working but the v9fs (9P) module has vanished from
> my Linux machine.  As root, I invoked the equivalent in C of
>
> 	mount -t 9P -o proto=fd,name=$LOGNAME,rfdno=%d,wfdno=%d '' /n/remote
>
> where %d is the file descriptor to communicate with the 9P server.
> The more common usage is
>
> 	mount -t 9P -o name=geoff 10.240.55.178 /n/remote

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Gorka guardiola]

Just to add a positive comment, worked for me instantly with no sweat with the
last fuse version, kernel 2.6, debian.
--
- curiosity sKilled the cat

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[csant]

> this allows me (without becoming root or having v9fs) to
> 	; mount $home/9/acme

But you'd have the 9p module, obviously. It's such a nonsene that the
linux kernel doesn't allow mounting for non-privileged users
out-of-the-box, IMO. I like filesystems in userspace.

/c

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[David Leimbach]

On 7/27/06, csant <csant@csant.info> wrote:
> > this allows me (without becoming root or having v9fs) to
> >       ; mount $home/9/acme
>
> But you'd have the 9p module, obviously. It's such a nonsene that the
> linux kernel doesn't allow mounting for non-privileged users
> out-of-the-box, IMO. I like filesystems in userspace.
>
Yeah but it did allow that, it would currently allow users to bind
their own passwd file or sudoers etc etc over /etc (unless they had an
implementation that prevented such things).

The problems in unix really were too deep to fix at some point... at
least in any elegant way :-)


> /c
>

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Scott Schwartz]

On Thu, Jul 27, 2006 at 10:50:29AM -0600, andrey mirtchovski wrote:
> >The fuse module is a kernel module, and part of the kernel tree,
> >the userland tools are not.
>
> i kept thinking that all i need to do is mount :)

Is there enough 9p support in linux 2.6 to do that without fuse?
Can someone who understands both compare this to v9fs?

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[erik quanstrom]

the /etc/(passwd|shadow) problem is solvable.  linux pam/shadow login supports ldap already,
the linux kernel supports 9p already and /bin/(login|su) could consult an authentication server
on the loopback device, if one were so inclined.  it's not like this would be a radical departure
from authentication methods pam already supports --- like ldap.

- erik

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Eric Van Hensbergen]

On 7/28/06, csant <csant@csant.info> wrote:
> > this allows me (without becoming root or having v9fs) to
> >       ; mount $home/9/acme
>
> But you'd have the 9p module, obviously. It's such a nonsene that the
> linux kernel doesn't allow mounting for non-privileged users
> out-of-the-box, IMO. I like filesystems in userspace.
>

This was discussed a bit at OLS -  there have been folks working
towards it for a bit, but I think we'll finally see it within the next
year.

       -eric

Re: Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[David Leimbach]

Oh I know it's solvable.

A buddy of mine had a PAM module where you only had to "not lose" a
game of tic tac toe to be authenticated.... So sure, there are lots of
options there.

My point was that I think I really like the way fossil doesn't really
do auth, yet still controls who's in what groups or at least appears
to control all of this through fscons.



On 7/28/06, erik quanstrom <quanstro@quanstro.net> wrote:
> the /etc/(passwd|shadow) problem is solvable.  linux pam/shadow login supports ldap already,
> the linux kernel supports 9p already and /bin/(login|su) could consult an authentication server
> on the loopback device, if one were so inclined.  it's not like this would be a radical departure
> from authentication methods pam already supports --- like ldap.
>
> - erik
>

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[David Leimbach]

On 7/28/06, Eric Van Hensbergen <ericvh@gmail.com> wrote:
> On 7/28/06, csant <csant@csant.info> wrote:
> > > this allows me (without becoming root or having v9fs) to
> > >       ; mount $home/9/acme
> >
> > But you'd have the 9p module, obviously. It's such a nonsene that the
> > linux kernel doesn't allow mounting for non-privileged users
> > out-of-the-box, IMO. I like filesystems in userspace.
> >
>
> This was discussed a bit at OLS -  there have been folks working
> towards it for a bit, but I think we'll finally see it within the next
> year.

I wonder how dragonflyBSD is coming along with their VFS "messaging"
stuff.  They want to make it easy to do SSI clusters (single system
image).  It sounds like FUSE would be completely redundant on this
platform, and one could implement 9p translation trivially.

I once asked if Matt had even looked at plan 9's way of making things
plug into the filesystem namespace via 9p and I actually don't
remember what his response was but he seemed that he really wanted to
do it his way :-)

Dave

>
>        -eric
>

Re: Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[erik quanstrom]

talk about reinventing the wheel!  once more with epicyclic gearing!
(apologies to arlo.)

- erik

On Fri Jul 28 08:58:14 CDT 2006, leimy2k@gmail.com wrote:
> I wonder how dragonflyBSD is coming along with their VFS "messaging"
> stuff.  They want to make it easy to do SSI clusters (single system
> image).  It sounds like FUSE would be completely redundant on this
> platform, and one could implement 9p translation trivially.
>
> I once asked if Matt had even looked at plan 9's way of making things
> plug into the filesystem namespace via 9p and I actually don't
> remember what his response was but he seemed that he really wanted to
> do it his way :-)
>
> Dave

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Ronald G Minnich]

csant wrote:

> But you'd have the 9p module, obviously. It's such a nonsene that the
> linux kernel doesn't allow mounting for non-privileged users
> out-of-the-box, IMO. I like filesystems in userspace.


it's an old argument which I have had had with multiple people multiple
times since 1998, and lost every time :-)

It's always "but why do you want that" and "you don't want that" or "we
can already to that" or "we tried that, it didn't work" and back to "but
why do you want that".

Charles nailed it. The Land That Time Forgot.

ron

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Ronald G Minnich]

David Leimbach wrote:

> Yeah but it did allow that, it would currently allow users to bind
> their own passwd file or sudoers etc etc over /etc (unless they had an
> implementation that prevented such things).

right, so in my v9fs on Linux 2.0, I made the 9p lack-of-attributes such
as dev inode, suid, ec. out as a virtue. You could not express most of
the ideas that were security issues in Unix.

If you add a few restrictions on where user mounts are allowed to go
(e.g. you're only allowed to mount on /private, for example), I think
you can knock a lot of the harder problems. It's all a hack, I guess,
but there's only so much you can do on Unix. I still think you can do
user mounts and still be safe.

ron

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Ronald G Minnich]

Scott Schwartz wrote:

> Is there enough 9p support in linux 2.6 to do that without fuse?

now you're depressing me. Yes, you can do 9p in linux 2.6 without fuse.
You just do a mount. I set a lot of mine up in /etc/fstab.

Or do you mean user mounts? Maybe I missed something.

> Can someone who understands both compare this to v9fs?

Fuse is cute, it works, it's fine for the local case. It seems to be
pretty solid. A very nice point solution, completely useless for what we
do here at LANL. It seems to be easier for people to figure out than 9p
servers. Another issue is that to date the 9p server libraries we had
were mostly p9p-based, and Linux people prefer not to use p9p libraries
to write software, I'm finding. Nothing wrong with p9p libraries, people
just don't want to deal with them. Lucho has developed native Unix
libraries which are pretty nice, and we're moving our software over to
those.

thanks


ron

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Eric Van Hensbergen]

On 7/28/06, Ronald G Minnich <rminnich@lanl.gov> wrote:
> Scott Schwartz wrote:
>
> > Is there enough 9p support in linux 2.6 to do that without fuse?
>
> now you're depressing me. Yes, you can do 9p in linux 2.6 without fuse.
> You just do a mount. I set a lot of mine up in /etc/fstab.
>
> Or do you mean user mounts? Maybe I missed something.
>

User mounts (w/either FUSE or 9p) can be "tricked out" with a set-uid
mount helper (9p's would be called mount.9P I think).  Such a helper
is also needed in 9p to do DNS resolution (NFS name resolution is the
only special-case in mount).  I believe Lucho had a 9p helper that
took care of DNS resolution, could be made setuid and maybe even tried
to handle auth.
Its in the app directory on v9fs' sourceforge CVS. The discussion of
OLS was about how to remove the need for having a set-uid helper.

     -eric

Re: [9fans] mount 9P on Linux and FreeBSD via FUSE

[Scott Schwartz]

On Fri, Jul 28, 2006 at 09:08:17AM -0600, Ronald G Minnich wrote:
> Scott Schwartz wrote:
>
> >Is there enough 9p support in linux 2.6 to do that without fuse?
>
> now you're depressing me. Yes, you can do 9p in linux 2.6 without fuse.
> You just do a mount. I set a lot of mine up in /etc/fstab.

That's what I thought, but I wanted to double check.
I'm not running 2.6 so it's hard to just try it. :)