257 lines
4.6 KiB
Text
257 lines
4.6 KiB
Text
.TH EXPORTFS 4
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.SH NAME
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exportfs, srvfs \- network file server plumbing
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.SH SYNOPSIS
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.B exportfs
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[
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.I options
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]
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.PP
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.B srvfs
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[
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.B -dR
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]
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[
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.B -p
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.I perm
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]
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[
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.B -P
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.I patternfile
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] [
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.B -e
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.I exportprog
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]
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.I name
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.I path
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.SH DESCRIPTION
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.I Exportfs
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is a user level file server that allows Plan 9 compute servers, rather
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than file servers, to export portions of a name space across networks.
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The service is started either by the
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.IR cpu (1)
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command or by a network listener process. An initial protocol
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establishes a root directory for the exported name space.
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The
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connection to
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.I exportfs
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is then mounted, typically on
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.BR /mnt/term .
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.I Exportfs
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then acts as a relay file server: operations in the imported file
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tree are executed on the remote server and the results returned. This
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gives the appearance of exporting a name space from a remote machine
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into a local file tree.
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.PP
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The options are:
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.TF "-A \fIaddress"
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.PD
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.TP
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.B -A \fIaddress
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Use the network
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.I address
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to announce
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.IR aan (8)
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connections,
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if requested by the initial protocol.
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.TP
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.B -a
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Authenticate the user with the
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.I p9any
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protocol before running the regular
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.I exportfs
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session; used when
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.I exportfs
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is invoked to handle an incoming network connection.
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.I Exportfs
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creates a new name space for each connection, using
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.B /lib/namespace
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by default (see
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.IR namespace (6)).
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.TP
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.B -B \fIaddress
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Dial
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.IR address ,
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authenticate as a
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.I p9any
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client, and then
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serve that network connection.
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Requires setting the root of the name space with
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.B -r
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or
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.BR -s .
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The remote system should run
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.B import
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.B -B
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to handle the call.
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See
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.IR import (4)
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for an example.
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.TP
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.B -d -f \fIdbgfile
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Log all 9P traffic to
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.I dbgfile
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(default
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.BR /tmp/exportdb ).
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.TP
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.B -e '\fIenc auth\fL'
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Set the encryption and authentication algorithms to use for
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encrypting the wire traffic (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 -m \fImsize
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Set the maximum message size that
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.I exportfs
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should offer to send (see
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.IR version (5));
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this helps tunneled
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9P connections to avoid unnecessary fragmentation.
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.TP
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.B -N \fInsfile
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Serve the name space described by
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.IR nsfile .
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.TP
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.B -n
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Disallow mounts by user
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.BR none .
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.TP
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.B -P \fIpatternfile
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Restrict the set of exported files.
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.I Patternfile
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contains one regular expression per line,
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to be matched against path names
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relative to the current working directory
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and starting with
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.BR ./ .
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For a file to be exported, all lines with a prefix
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.B +
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must match and all those with prefix
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.B -
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must not match.
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.TP
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.B -R
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Make the served name space read only.
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.TP
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.B -r \fIroot
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Bypass the initial protocol, serving the name space rooted at
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.IR root .
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.TP
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.B -S \fIservice
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bypass the initial protocol, serving the result of mounting
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.IR service .
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A separate mount is used for each
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.IR attach (5)
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message,
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to correctly handle servers in which each mount
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corresponds to a different client
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.IR e.g. , (
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.IR rio (4)).
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.TP
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.B -s
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equivalent to
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.B -r
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.BR / ;
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kept for compatibility.
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.PD
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.PP
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The
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.B cpu
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command uses
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.I exportfs
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to serve device files in the terminal. The
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.IR import (4)
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command calls
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.I exportfs
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on a remote machine, permitting users to access arbitrary pieces of
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name space on other systems.
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.PP
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Because the kernel disallows reads and writes on mounted pipes
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(as might be found in
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.BR /srv ),
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.I exportfs
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calls itself (with appropriate
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.B -m
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and
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.B -S
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options) to simulate reads and writes on such files.
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.PP
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.I Srvfs
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invokes
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.I exportprog
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(default
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.BR /bin/exportfs )
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to create a mountable file system from a name space
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and posts it at
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.BI /srv/ name ,
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which is created with mode
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.I perm
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(default 0600).
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The name space is the directory tree rooted at
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.IR path .
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The
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.BR -d ,
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.BR -P ,
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and
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.B -R
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options, if present, are relayed to
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.IR exportprog .
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.SH EXAMPLES
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To export the archive of one user for one month, except for secrets,
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.IP
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.EX
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cd /n/dump
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echo '+ ^\e.(/2003(/10..(/usr(/glenda/?)?)?)?)?' > /tmp/pattern
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echo '- \e.(aes|pgp)$' >> /tmp/pattern
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exportfs -P /tmp/pattern
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.EE
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.LP
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Use
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.I srvfs
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to enable mounting of an FTP file system (see
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.IR ftpfs (4))
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in several windows,
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or to publish a
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.B /proc
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(see
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.IR proc (3))
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with a broken process so a remote person may debug the program:
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.IP
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.EX
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srvfs ftp /n/ftp
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srvfs broke /mnt/term/proc
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.EE
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.LP
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Use
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.I srvfs
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to obtain a copy of a service to be manipulated directly
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by a user program like
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.IR nfsserver (8):
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.IP
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.EX
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srvfs nfs.boot /srv/boot
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aux/nfsserver -f /srv/nfs.boot
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.EE
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.LP
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Use
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.I srvfs
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to spy on all accesses to a particular subtree:
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.IP
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.EX
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srvfs -d spy /
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tail -f /tmp/exportdb &
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mount /srv/spy /n/spy
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cd /n/spy; ls
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.EE
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.SH SOURCE
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.B /sys/src/cmd/exportfs
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.br
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.B /sys/src/cmd/srvfs.c
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.SH SEE ALSO
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.IR dial (2),
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.IR import (4),
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.IR aan (8),
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.IR listen (8)
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