Subversion Repositories planix.SVN

.TH CONSOLEFS 4

.SH NAME

consolefs, C, clog  \- file system for console access

.SH SYNOPSIS

.B aux/consolefs

[

.B -m

.I mntpt

] [

.B -c

.I consoledb

]

.PP

.B C

.I system

.PP

.B aux/clog

console log

.I system

.SH DESCRIPTION

To ease administration of multiple machines one might attach

many serial console lines to a single computer.

.I Consolefs

is a file system that lets multiple users simultaneously access

these console lines.

The consoles and permissions to access them are defined in the

file

.I consoledb

(default

.BR /lib/ndb/consoledb ).

The format of

.I consoledb

is the same as that of other

.B /lib/ndb

files,

.IR ndb (6).

Consoles are defined by entries of the form:

.PP

.EX

	console=dirty dev=/dev/eia205

		uid=bignose

		gid=support

		speed=56200

		cronly=

.EE

.PP

Each

.IR console / dev

pair represents the name of a console and the device

associated with it.

.I Consolefs

presents a single level directory with up to three files

per console:

.IR console ,

.IB console ctl\f1,

and

.IB console stat\f1.

Writes of

.I console

are equivalent to writes of

.I dev

and reads and writes of

.IB console ctl

and 

.IB console stat

are equivalent to reads and writes of

.IB dev ctl

and

.IB dev stat

respectively.

.IB Console ctl

and

.IB console stat

will not exist if the underlying

.I dev

does not provide them.

.I Consolefs

broadcasts anything it reads from

.I dev

to all readers of

.IR console .

Therefore, many users can

.IR con (1)

to a 

.IR console ,

see all output, and enter commands.

.PP

The

.I cronly=

attribute causes newlines typed by the user to be sent to

the console as returns.

The

.I speed=x

attribute/value pair specifies a bit rate for the

console.  The default is 9600 baud.

The

.I openondemand=

attribute causes the console device

.RI ( dev )

to be opened only when the corresponding

.IB mntpt / console

file is open.

.PP

Access to the console is controlled by the

.I uid

and

.I gid

attributes/value pairs.

The uid values are user account names.

The gid values are the names of groups defined in

.I consolefs

by entries of the form:

.PP

.EX

	group=support

		uid=bob

		uid=carol

		uid=ted

		uid=alice

.EE

.PP

Groups are used to avoid excessive typing.  Using

.I gid=x

is equivalent to including a

.I uid=y

for each user

.I y

that is a member of

.IR x .

.PP

To keep users from inadvertently interfering with one another,

notification is broadcast to all readers whenever a user

opens or closes

.IR name .

For example, if user

.B boris

opens a console that users

.B vlad

and

.B barney

have already opened, all will read the message:

.PP

.EX

	[+boris, vlad, barney]

.EE

.PP

If

.B vlad

then closes,

.B boris

and 

.B barney

will read:

.PP

.EX

	[-vlad, boris, barney]

.EE

.PP

.I Consolefs

posts the client end of its 9P channel in

.BR /srv/consolefs

and mounts this locally in

.I mntpt

(default

.BR /mnt/consoles );

remote clients must

.B mount

(see

.IR bind (1))

this file to see the consoles.

.PP

The

.IR rc (1)

script

.B C

automates this procedure.

It uses

.IR import (4)

to connect to

.B /mnt/consoles

on the machine connected to all the consoles, then uses

.IR con (1)

to connect to the console of the machine

.IR system.

The script must be edited at installation

by the local administration to identify the

system that holds

.BR /mnt/consoles .

.PP

.I Aux/clog

opens the file

.I console

and writes every line read from it, prefixed

by the ASCII time to the file

.IR log .

.PP

An example of 2 consoles complete with console logging is:

.IP

.EX

% cat /lib/ndb/consoledb

group=sys

	uid=glenda

console=bootes dev=/dev/eia0 gid=sys

console=fornax dev=/dev/eia1 gid=sys

% aux/consolefs

% ls -p /mnt/consoles

bootes

bootesctl

fornax

fornaxctl

% clog /mnt/consoles/fornax /sys/log/fornax &

% clog /mnt/consoles/bootes /sys/log/bootes &

.EE

.PP

The console server's default name space must 

mount the consoles for 

.I C

to import.

This can be arranged by adding

.IP

.EX

mount /srv/consoles /mnt/consoles

.EE

.LP

to

.BR /lib/namespace.$sysname .

.SH FILES

.TF /lib/ndb/consoledb

.TP

.B /srv/consoles

Client end of pipe to server.

.TP

.B /mnt/consoles

Default mount point.

.TP

.B /lib/ndb/consoledb

Default user database.

.SH SOURCE

.B /sys/src/cmd/aux/consolefs.c

.br

.B /rc/bin/C

.br

.B /sys/src/cmd/aux/clog.c

.SH BUGS

.PP

Changing the gid's or uid's while

.I consolefs

is running

is detected by

.IR consolefs .

However, to add new consoles

one must restart

.IR consolefs .