.TH EXPORTFS 4
.SH NAME
exportfs, srvfs \- file server plumbing
.SH SYNOPSIS
.B exportfs
[
.B -dsR
]
[
.B -m
.I msize
]
[
.B -r
.I root
]
[
.B -P
.I patternfile
]
[
.B -S
.I srvfile
]
.PP
.B srvfs
[
.B -dR
]
[
.B -p
.I perm
]
[
.B -P
.I patternfile
] [
.B -e
.I exportprog
]
.I name
.I path
.SH DESCRIPTION
.I Exportfs
is a user level file server that allows Plan 9 cpu servers, rather
than file servers, to export portions of a name space.
It is usually started by other programs such as
.IR rcpu (1)
after a secure channel has been established.
.I Exportfs
then acts as a relay file server: operations in the imported file
tree are executed on the remote server and the results returned.  This
gives the appearance of exporting a name space from a remote machine
into a local file tree.
.PP
The options are:
.TP
.B -d
Log all 9P traffic to standard error.
.TP
.B -P \fIpatternfile
Restrict the set of exported files.
.I Patternfile
contains one regular expression per line,
to be matched against path names
relative to the current working directory
and starting with
.BR / .
For a file to be exported, all lines with a prefix
.B +
must match and all those with prefix
.B -
must not match.
.TP
.B -R
Make the served name space read only.
.TP
.B -r \fIroot
Serve the name space rooted at
.IR root .
.TP
.B -S \fIservice
Serve the result of mounting
.IR service .
A separate mount is used for each
.IR attach (5)
message,
to correctly handle servers in which each mount
corresponds to a different client
.IR e.g. , (
.IR rio (4)).
.TP
.B -s
equivalent to
.B -r
.BR / ;
kept for compatibility.
.TP
.B -m \fImsize
Set the maximum message size that 
.I exportfs
should offer to send (see
.IR version (5));
this helps tunneled
9P connections to avoid unnecessary fragmentation.
.PD
.PP
.I Srvfs
invokes
.I exportprog
(default
.BR /bin/exportfs )
to create a mountable file system from a name space
and posts it at
.BI /srv/ name ,
which is created with mode
.I perm
(default 0600).
The name space is the directory tree rooted at 
.IR path .
The
.BR -d ,
.BR -P ,
and
.B -R
options, if present, are relayed to
.IR exportprog .
.SH EXAMPLES
To export the archive of one user for one month, except for secrets,
.IP
.EX
cd /n/dump
echo '+ ^/(2003(/10..(/usr(/glenda/?)?)?)?)?' > /tmp/pattern
echo '- \e.(aes|pgp)$' >> /tmp/pattern
exportfs -P /tmp/pattern
.EE
.LP
Use
.I srvfs
to enable mounting of an FTP file system (see
.IR ftpfs (4))
in several windows, 
or to publish a
.B /proc
(see
.IR proc (3))
with a broken process so a remote person may debug the program:
.IP
.EX
srvfs ftp /n/ftp
srvfs broke /mnt/term/proc
.EE
.LP
Use 
.I srvfs
to obtain a copy of a service to be manipulated directly
by a user program like
.IR nfsserver (8):
.IP
.EX
srvfs nfs.boot /srv/boot
aux/nfsserver -f /srv/nfs.boot
.EE
.LP
Use
.I srvfs
to spy on all accesses to a particular subtree:
.IP
.EX
srvfs -d spy /
tail -f /tmp/exportdb &
mount /srv/spy /n/spy
cd /n/spy; ls
.EE
.SH SOURCE
.B /sys/src/cmd/exportfs
.br
.B /sys/src/cmd/srvfs.c
.SH SEE ALSO
.IR rcpu (1)