OFS(4) OFS(4)
NAME
ofs - mount a file server speaking Op using Styx
SYNOPSIS
o/ofs [ -Adv ] [ -C alg ] [ -k keyfile ] [ -m mnt ] [ -c dir
] netaddr [ path ]
DESCRIPTION
Ofs dials the Op file server found at addr and mounts it at
mnt. Here, addr may be a file representing a connection,
like /fd/0 or any other file. It speaks both Styx (as a
server) and Op (as a client) and provides a Styx file server
to mount in Inferno file trees served from Op servers. Usu-
ally, the server mounted is oxport(4), used to export a name
space using Op. The path (subtree) served by the Op server
is / by default, but may be supplied as an option.
This program exists because Op is faster than Styx, regard-
ing latency, on network links with bad latency, being the
main reason that Op requires less RPCs than Styx for doing
the same thing. However, there are some issues to be taken
into account when using this program to export devices. See
intro(O) for a discussion.
In general, files are retrieved from the server with a sin-
gle get(O) operation. Big files require further RPCs. All
writes are indeed write-through, although those that are not
the first write, and use a full Styx packet, are sent asyn-
chronously (like in delayed writes).
If mnt is given, it mounts itself using flags MREPL and
MCREATE at the directory named by mnt. Otherwise, it uses
standard input to serve files speaking Styx (this is
intended for use with mount(1).
By default, ofs authenticates the client when mounting
itself, and encrypts the channel using RC4. Authentication
can be disabled with the -A flag, and the algorithm used to
sign/encrypt the channel may be changed using -C and supply-
ing the algorithm name in arg (as said in ssl(3)). The key-
file used for authentication follows the standard convention
used in Inferno, but may be otherwise specified to be
keyfile using -k.
When the special name auto is given in mnt the program reads
a system name from the connection, before mounting it, and
uses /term/remotename to automatically mount the remote
tree. The system name is read by first reading 9 bytes,
which should be a UTF-8 string with 8 digits in printable
form and a new line. Then, it reads so many bytes and takes
OFS(4) OFS(4)
that string (in UTF-8) to be the remote system name.
Flag -d enables (very) verbose debug diagnostics. Trying to
access a file named !!DUMP dumps the internal state of the
cache, for debugging.
Flag -v makes the program report some protocol statistics
before exiting.
Flag -c instructs ofs to use a local, on-disk, cache located
at dir to keep files fetched/update from/to the server. The
cache is only used to serve read requests for files that are
not entirely cached on-memory (that is, for files that are
not quite small). The directory structure reflects that of
the server. One nice side-effect of using this cache is that
files updated to the server are still kept in the local
disk, should the connection to the server fail.
EXAMPLE
Import (using Op) a remote file tree and mount it at /n/pc.
o/ofs -m /n/pc tcp!opserver.org!10000
Import a locally-served file tree using mount (ie., start
Ofs using standard input as the Styx connection).
mount -c {o/ofs -C rc4 tcp!127.0.0.1!10000} /n/pc
Listen for calls from a remote export program, and make
remote trees available at /term/$remotesysname (encrypting
the channel). Where, $remotesysname is given by the export
program at the other end.
listen -tv 'tcp!*!17004' {
o/ofs -A -d -m auto /fd/0 >[2]/dev/cons&
}
SOURCE
/usr/octopus/port/ofs
SEE ALSO
intro(O) and oxport(4).