ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
dir: /sys/man/4/import/
.TH IMPORT 4 .SH NAME import \- import a name space from a remote system .SH SYNOPSIS .B import [ .I options ] .I system .I file [ .I mountpoint ] .PP .B import .B -B [ .I options ] .I mountpoint [ .I cmd [ .I args ... ] ] .SH DESCRIPTION .I Import allows an arbitrary .I file on a remote .I system to be imported into the local name space. Usually .I file is a directory, so the complete file tree under the directory is made available. .PP A process is started on the remote machine, with authority of the user of .IR import , to perform work for the local machine using the .IR exportfs (4) service. The default port used is TCP 17007. If .I mountpoint is omitted .I import uses the name of the remote .I file as the local mount point. .PP The options are: .TF "-s namexxx" .PD .TP .B -a -b -c -C Control the construction of union directories, as in .I mount and .IR bind (1). Only valid when .I file is a directory. .TP .B -A Skip the authentication protocol. This is useful for connecting to foreign systems like Inferno. .TP .B -z Bypass the initial protocol request for which remote tree to serve. This is necessary when the remote .IR exportfs (4) is running with the .B -r or .B -S options which pre-select a file tree to serve. The exception is if both sides are operating in the .B -B backwards mode. .TP .B -B Run in ``backwards'' mode, described below. .TP .B -E \fIenc Push an encryption protocol on its network connection. The supported protocols are .B clear (the default, no protocol) and .BR ssl . There are plans to make .B tls available. .TP .B -e '\fIenc hash\fR' Specify the encryption and hash algorithms to use for encrypting and authenticating the wire traffic (see .IR ssl (3)). The defaults are .B rc4_256 and .BR sha1 . .TP .B -k \fIkeypattern Use .I keypattern to select a key to authenticate to the remote side (see .IR auth (2)). .TP .B -p Push the .IR aan (8) filter onto the connection to protect against temporary network outages. .TP .B -n Specify announce string for .IR aan (8) filter when run in ``backwards'' mode. .TP .B -s \fIname Post the connection's mountable file descriptor as .BI /srv/ name\fR. .PD .PP The .B -B option runs .I import in ``backwards'' mode. In this mode, .I import runs a .I p9any authentication (as server) over its file descriptor 0 (expected to be an incoming network connection from .B exportfs .BR -B ), mounts the connection onto .IR mntpt , and optionally runs .I cmd .IR args . .SH EXAMPLES Assume a machine .B kremvax that has IP interfaces for the company intranet and the global internet mounted on .I /net and .I /net.alt respectively. Any machine inside the company can get telnet out to the global internet using: .IP .EX import -a kremvax /net.alt telnet /net.alt/tcp!ucbvax .EE .PP Suppose that the machine .B moscvax has access to a private file server containing public web pages that need to be served by the less-trusted server .BR webvax . .B Webvax runs the following listener (see .IR listen (8)) on TCP port 999: .IP .EX #!/bin/rc import -B -s rowebfs /usr/web /bin/restarthttpd .EE .PP When .B moscvax boots, it runs .IP .EX exportfs -R -r /usr/web -B tcp!webvax!999 .EE .PP to serve a read-only copy of .B /usr/web to .BR webvax . When .B webvax gets the call, .B import mounts the served tree onto its own .B /usr/web and then runs .B /bin/restarthttpd to restart .IR httpd (8). .SH SOURCE .B /sys/src/cmd/import.c .SH SEE ALSO .IR bind (1), .IR ssl (3), .IR exportfs (4), .IR srv (4), .IR aan (8), .IR listen (8), .B cs in .IR ndb (8)