term% cat index.txt IMPORT(4) Kernel Interfaces Manual IMPORT(4)
NAME
import - import a name space from a remote system
SYNOPSIS
import [ options ] system file [ mountpoint ]
import -B [ options ] mountpoint [ cmd [ args ... ] ]
DESCRIPTION
Import allows an arbitrary file on a remote system to be imported into
the local name space. Usually file is a directory, so the complete
file tree under the directory is made available.
A process is started on the remote machine, with authority of the user
of import, to perform work for the local machine using the exportfs(4)
service. The default port used is TCP 17007. If mountpoint is omitted
import uses the name of the remote file as the local mount point.
The options are:
-a -b -c -C
Control the construction of union directories, as in mount and
bind(1). Only valid when file is a directory.
-A Skip the authentication protocol. This is useful for connecting
to foreign systems like Inferno.
-z Bypass the initial protocol request for which remote tree to
serve. This is necessary when the remote exportfs(4) is running
with the -r or -S options which pre-select a file tree to serve.
The exception is if both sides are operating in the -B backwards
mode.
-B Run in ``backwards'' mode, described below.
-E enc Push an authentication protocol on its network connection. The
supported protocols are clear (the default, no protocol) and
ssl. There are plans to make tls available.
-e 'enc auth'
Specify the encryption and authentication algorithms to use for
encrypting the wire traffic (see ssl(3)). The defaults are
rc4_256 and sha1.
-k keypattern
Use keypattern to select a key to authenticate to the remote
side (see auth(2)).
-o -O These equivalent flags run import in a pre-9P2000 compatibility
mode to import from ancient servers.
-p Push the aan(8) filter onto the connection to protect against
temporary network outages.
-n Specify announce string for aan(8) filter when run in ``back‐
wards'' mode.
-s name
Post the connection's mountable file descriptor as /srv/name.
The -B option runs import in ``backwards'' mode. In this mode, import
runs a p9any authentication (as server) over its file descriptor 0 (ex‐
pected to be an incoming network connection from exportfs -B), mounts
the connection onto mntpt, and optionally runs cmd args.
EXAMPLES
Assume a machine kremvax that has IP interfaces for the company in‐
tranet and the global internet mounted on /net and /net.alt respec‐
tively. Any machine inside the company can get telnet out to the
global internet using:
import -a kremvax /net.alt
telnet /net.alt/tcp!ucbvax
Suppose that the machine moscvax has access to a private file server
containing public web pages that need to be served by the less-trusted
server webvax. Webvax runs the following listener (see listen(8)) on
TCP port 999:
#!/bin/rc
import -B -s rowebfs /usr/web /bin/restarthttpd
When moscvax boots, it runs
exportfs -R -r /usr/web -B tcp!webvax!999
to serve a read-only copy of /usr/web to webvax. When webvax gets the
call, import mounts the served tree onto its own /usr/web and then runs
/bin/restarthttpd to restart httpd(8).
SOURCE
/sys/src/cmd/import.c
SEE ALSO
bind(1), ssl(3), exportfs(4), srv(4), aan(8), listen(8), cs in ndb(8)
IMPORT(4)