IMPORT(4) IMPORT(4)
NAME
import - import a name space from a remote system
SYNOPSIS
import [ options ] system file [ mountpoint ]
import -m [ options ] system 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 use-
ful for connecting to foreign systems like
Inferno.
-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 algo-
rithms 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-
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IMPORT(4) IMPORT(4)
9P2000 compatibility mode to import from ancient
servers.
-p Push the aan(8) filter onto the connection to
protect against temporary network outages.
-s name Post the connection's mountable file descriptor
as /srv/name.
The -m option mounts a file exported by exportfs(4) with its
-r or -S options, which skip the part of its protocol that
allows the importer to specify the file to export. Instead,
the file or name space is selected by exportfs, and import
mounts it on mountpoint as guided by the other options.
The -B option runs import in ``backwards'' mode. In this
mode, import runs a p9any authentication (as server) over
its file descriptor 0 (expected 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 com-
pany intranet and the global internet mounted on /net and
/net.alt respectively. 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
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IMPORT(4) IMPORT(4)
in ndb(8)
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