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