from brian.  update the 9p manual page to cover
authentication.

Reference: /n/atom/patch/applied2013/9pauth
Date: Fri Jul 12 21:39:15 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/man/2/9p	Fri Jul 12 21:35:27 2013
+++ /sys/man/2/9p	Fri Jul 12 21:35:27 2013
@@ -85,6 +85,15 @@
 .PP
 .nf
 .ft L
+void	auth9p(Req *r)
+int	authattach(Req *r)
+void	authdestroy(Fie *fid)
+void	authread(Req *r)
+void	authwrite(Req *r)
+.fi
+.PP
+.nf
+.ft L
 .ta \w'\fLvoid* 'u
 void*	emalloc9p(ulong n)
 void*	erealloc9p(void *v, ulong n)
@@ -369,6 +378,57 @@
 .I ARGBEGIN
 (see
 .IR arg (2)).
+.IP
+If the
+.I auth
+member of the
+.B Srv
+structure is set to
+.IR auth9p ,
+the server will prepare for a
+.I p9any
+authentication in conjunction with
+.IR factotum (4).
+When using
+.IR auth9p ,
+the
+.IR read ,
+.IR write ,
+and
+.I destroy
+service functions should call
+.IR authread ,
+.IR authwrite ,
+and
+.IR authdestroy ,
+respectively when operating on a
+.B Fid
+where
+.IB r -> fid -> qid.type
+has the
+.B QTAUTH
+flag set.
+In all three cases the
+.I auth
+function makes the
+.I respond
+call.
+Finally, before carrying out the normal attach operation, the
+.I attach
+service function should call
+.IR authattach .
+If there is an authentication error, then
+.I authattach
+will return
+.B -1
+and will have called
+.I respond
+with an appropriate error.
+Otherwise, the
+.I attach
+service function should continue and call
+.I respond
+when it's done.
 .TP
 .I Attach
 The