OXPORT(4) OXPORT(4)
NAME
oxport - export name space on a connection using Op
SYNOPSIS
o/oxport [ -Ad ] [ -L ms ] [ -x addr ] dir
DESCRIPTION
Oxport serves a name space rooted at dir over a connection
to an Op client. The connection is indeed standard input,
because the program is implemented to be used with
listen(1). Using oxport is more efficient in terms of
latency than using export(4) for RTTs of 1ms or more.
The program does not fork the current name space, any change
to the current name space will be visible to clients. This
is appropriate for exporting the PC name space to terminals,
while still seeing any change made to the exported namespace
(eg., new terminal arrivals) but it means that care has to
be taken to avoid deadlocks (caused whenever the exported
namespace is mounted in the namespace used by the program).
The connection is assumed to be trusted and authenticated,
on the name of the first user attaching to the exported file
tree.
Flag -x can be used to make oxport dial addr and serve dir
over the connection, after reporting the local system name
to the other end. See ofs(4) for the details. This is used
in the octopus to export portions of terminals to the cen-
tral PC. In this case, the program authenticates and
encrypts the connection, unless -A is given as an option.
Note that in the usual case of running oxport from listen it
will not authenticate or encrypt the channel. That is
assumed to be done by listen and not by this program.
Flag -L is used to debug the protocol by pretending that the
RTT for a RPC is at least ms milliseconds for a message. The
implementation is a call to sleep(2) before attending each
client request. Client requests are served concurrently,
thus this should not affect throughput.
See intro(O) for a description of the protocol spoken. This
is important if this program is being used to export
devices.
EXAMPLE
Export (using Op) the entire file tree seen in the current
name space to clients connecting to tcp!127.0.0.1!4242
(without authentication nor encryption of the communication
OXPORT(4) OXPORT(4)
channel, but with debugging messages enabled):
listen -At tcp!127.0.0.1!4242 oxport -d / >[2]/dev/cons
Export our home directory to clients that authenticate,
encrypting the communication channel:
listen -a rc4 -t tcp!127.0.0.1!10000 {o/oxport
/usr/nemo}
Export the directory /term to the Op client listening at the
given address:
o/oxport -x tcp!alboran!16699 /term
SOURCE
/usr/octopus/port/oxport.b
SEE ALSO
intro(O) and ofs(4).
BUGS
Currently, oxport denies access for subtrees of the direc-
tory exported other than / (that is, it prevents the use of
the field path in attach(O) requests).