oexportfs: move legacy code for cpu and import to separate program

The initial protocol handling in exportfs for
cpu and import services is a huge mess.

Saparate the code out into its own program with
its own oexportfs(4) manpage.

2 files changed, 163 insertions, 107 deletions

diff --git a/sys/man/4/exportfs b/sys/man/4/exportfs
index b7cbeb979..b6108c1ab 100644
--- a/sys/man/4/exportfs
+++ b/sys/man/4/exportfs
@@ -1,6 +1,6 @@
 .TH EXPORTFS 4
 .SH NAME
-exportfs, srvfs \- network file server plumbing
+exportfs, srvfs \- file server plumbing
 .SH SYNOPSIS
 .B exportfs
 [
@@ -26,17 +26,11 @@ exportfs, srvfs \- network file server plumbing
 .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 .
+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
@@ -44,49 +38,6 @@ 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
@@ -94,31 +45,6 @@ Log all 9P traffic to
 (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
@@ -137,11 +63,11 @@ must not match.
 Make the served name space read only.
 .TP
 .B -r \fIroot
-Bypass the initial protocol, serving the name space rooted at
+Serve the name space rooted at
 .IR root .
 .TP
 .B -S \fIservice
-bypass the initial protocol, serving the result of mounting
+Serve the result of mounting
 .IR service .
 A separate mount is used for each
 .IR attach (5)
@@ -156,28 +82,15 @@ 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 ),
+.TP
+.B -m \fImsize
+Set the maximum message size that 
 .I exportfs
-calls itself (with appropriate
-.B -m
-and
-.B -S 
-options) to simulate reads and writes on such files.
+should offer to send (see
+.IR version (5));
+this helps tunneled
+9P connections to avoid unnecessary fragmentation.
+.PD
 .PP
 .I Srvfs
 invokes
@@ -251,7 +164,4 @@ cd /n/spy; ls
 .br
 .B /sys/src/cmd/srvfs.c
 .SH SEE ALSO
-.IR dial (2),
-.IR import (4),
-.IR aan (8),
-.IR listen (8)
+.IR rcpu (1)
diff --git a/sys/man/4/oexportfs b/sys/man/4/oexportfs
new file mode 100644
index 000000000..180ad204f
--- /dev/null
+++ b/sys/man/4/oexportfs
@@ -0,0 +1,146 @@
+.TH OEXPORTFS 4
+.SH NAME
+oexportfs \- legacy exportfs for cpu and import
+.SH SYNOPSIS
+.PP
+.B oexportfs
+[
+.I options
+]
+.SH DESCRIPTION
+.I Oexportfs
+is older version of the
+.IR exportfs (4)
+program that handles an initial protocol to establish a root directory
+for the exported name space.
+It also provides authentication and encryption using
+the
+.IR ssl (3)
+device.
+.PP
+It is used exclusively by the deprecated
+.IR cpu (1)
+and
+.IR import (4)
+services.
+.PP
+The options are:
+.TP
+.B -d -f \fIdbgfile
+Log all 9P traffic to
+.I dbgfile
+(default
+.BR /tmp/exportdb ).
+.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 oexportfs
+should offer to send (see
+.IR version (5));
+this helps tunneled
+9P connections to avoid unnecessary fragmentation.
+.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 oexportfs
+session; used when 
+.I oexportfs
+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 -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 -N \fInsfile
+Serve the name space described by
+.IR nsfile .
+.TP
+.B -n
+Disallow mounts by user
+.BR none .
+.EE
+.SH SOURCE
+.B /sys/src/cmd/exportfs/oexportfs.c
+.SH SEE ALSO
+.IR dial (2),
+.IR exportfs (4),
+.IR import (4),
+.IR aan (8),
+.IR listen (8)