ref: 341b64b5bd0af48ec4bb7b11a54c953c52b22d03
dir: /sys/man/4/exportfs/
.TH EXPORTFS 4 .SH NAME exportfs, srvfs \- network file server plumbing .SH SYNOPSIS .B exportfs [ .I options ] .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 compute servers, rather than file servers, to export portions of a name space across networks. The service is started either by the .IR cpu (1) command or by a network listener process. An initial protocol establishes a root directory for the exported name space. The connection to .I exportfs is then mounted, typically on .BR /mnt/term . .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: .TF "-A \fIaddress" .PD .TP .B -A \fIaddress Use the network .I address to announce .IR aan (8) connections, if requested by the initial protocol. .TP .B -a Authenticate the user with the .I p9any protocol before running the regular .I exportfs session; used when .I exportfs is invoked to handle an incoming network connection. .I Exportfs creates a new name space for each connection, using .B /lib/namespace by default (see .IR namespace (6)). .TP .B -B \fIaddress Dial .IR address , authenticate as a .I p9any client, and then serve that network connection. Requires setting the root of the name space with .B -r or .BR -s . The remote system should run .B import .B -B to handle the call. See .IR import (4) for an example. .TP .B -d -f \fIdbgfile Log all 9P traffic to .I dbgfile (default .BR /tmp/exportdb ). .TP .B -e '\fIenc auth\fL' Set the encryption and authentication algorithms to use for encrypting the wire traffic (see .IR ssl (3)). The defaults are .B rc4_256 and .BR sha1 . .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. .TP .B -N \fInsfile Serve the name space described by .IR nsfile . .TP .B -n Disallow mounts by user .BR none . .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 Bypass the initial protocol, serving the name space rooted at .IR root . .TP .B -S \fIservice bypass the initial protocol, serving 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. .PD .PP The .B cpu command uses .I exportfs to serve device files in the terminal. The .IR import (4) command calls .I exportfs on a remote machine, permitting users to access arbitrary pieces of name space on other systems. .PP Because the kernel disallows reads and writes on mounted pipes (as might be found in .BR /srv ), .I exportfs calls itself (with appropriate .B -m and .B -S options) to simulate reads and writes on such files. .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 dial (2), .IR import (4), .IR aan (8), .IR listen (8)