srv9 - plan 9 server registry

 bind -c #₪ /srv 
 /srv/ service1  /srv/ service2  ...

On Inferno hosted on Plan 9, srv9 serves a one-level directory that gives Inferno applications direct access to Plan 9 services posted in its #s server registry, and allows Inferno applications to post services for access by Plan 9 applications. A service is represented by a file descriptor, usually serving the common file service protocol described in intro (5), allowing it to be mounted (see bind (1) and sys-bind (2)) in the name space of an application in the other system.

To access a Plan 9 service in Inferno, open the desired service file; the resulting file descriptor is connected to the associated Plan 9 service. When that service is a shared Plan 9 file service, srv9 automatically starts Plan 9's exportfs with appropriate options to make the service accessible from Inferno. It can safely be shared with Plan 9 applications, but note that any path names mentioned in the attach specifier (see mount (1) and attach (5)) will be in the Plan 9 application's name space, not the Inferno application's. (Indeed, a similar caveat applies in Plan 9 itself.)

To export an Inferno service to Plan 9, create a new file such as /srv/myserv using Sys->create with mode Sys->ORDWR (see sys-open (2)) and any desired permissions for the new service file. (Note that the #₪ device must have been bound in with the -c option, as shown above, to allow file creation.) If the create is successful, Plan 9's service registry will have a new entry myserv , and the file descriptor returned from create acts as a pipe to any Plan 9 application that opens the associated service file in Plan 9. Typically on the Inferno side the file descriptor is passed to sys-export (2) or made the standard input of an Inferno file service (see intro (4)). The Plan 9 service file is automatically removed when the Inferno file descriptor is no longer referenced.

To make Plan 9's factotum available in Inferno: .EX mount -Aa /srv/factotum /mnt

(Note the -A option to suppress Inferno authentication.)

To mount the Plan 9 file service from which a Plan 9 machine booted:

.EX mount -9 /srv/boot /n/local

The -9 option to mount (1) requests Plan 9 authentication; that could also have been used instead of -A in the previous example.

To make the environment variables of the current Inferno name space available to Plan 9:

.EX fd := sys->create("/srv/infenv", Sys->ORDWR, 8r600); sys->export(fd, "/env", Sys->EXPWAIT); /emu/Plan9/devsrv9.c sys-bind (2), sys-open (2), sys-export (2), import (4), 9srvfs (4)