CONSOLEFS(4) CONSOLEFS(4)
NAME
consolefs, C, clog - file system for console access
SYNOPSIS
aux/consolefs [ -m mntpt ] [ -c consoledb ]
C system
aux/clog console log system
DESCRIPTION
To ease administration of multiple machines one might attach
many serial console lines to a single computer. 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 consoledb (default
/lib/ndb/consoledb). The format of consoledb is the same as
that of other /lib/ndb files, ndb(6). Consoles are defined
by entries of the form:
console=dirty dev=/dev/eia205
uid=bignose
gid=support
speed=56200
cronly=
Each console/dev pair represents the name of a console and
the serial line device associated with it. Consolefs pre-
sents a single level directory with two files per console:
console and consolectl. Writes of console are equivalent to
writes of dev and reads and writes of consolectl are equiva-
lent to reads and writes of devctl. Consolefs broadcasts
anything it reads from dev to all readers of console. There-
fore, many users can con(1) to a console, see all output,
and enter commands.
The cronly= attribute causes newlines typed by the user to
be sent to the console as returns. The speed=x
attribute/value pair specifies a bit rate for the console.
The default is 9600 baud.
Access to the console is controlled by the uid and gid
attributes/value pairs. The uid values are user account
names. The gid values are the names of groups defined in
consolefs by enties of the form:
group=support
uid=alice
uid=bob
uid=ted
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CONSOLEFS(4) CONSOLEFS(4)
uid=mary
Groups are used to avoid excessive typing. Using gid=x is
equivalent to including a uid=y for each user y that is a
member of x.
To keep users from inadvertently interfering with one
another, notification is broadcast to all readers whenever a
user opens or closes name. For example, if user boris opens
a console that users vlad and barney have already opened,
all will read the message:
[+boris, vlad, barney]
If vlad then closes, boris and barney will read:
[-vlad, boris, barney]
Consolefs posts the client end of its 9P channel in
/srv/consolefs and mounts this locally in mntpt (default
/mnt/consoles); remote clients must mount (see bind(1)) this
file to see the consoles.
The rc(1) script C automates this procedure. It uses
import(4) to connect to /mnt/consoles on the machine con-
nected to all the consoles, then uses con(1) to connect to
the console of the machine system. The script must be edited
at installation by the local administration to identify the
system that holds /mnt/consoles.
Aux/clog opens the file console and writes every line read
from it, prefixed by the ASCII time to the file log.
An example of 2 consoles complete with console logging is:
% aux/consolefs
% ls -p /mnt/consoles
bootes
bootesctl
fornax
fornaxctl
% clog /mnt/consoles/fornax /sys/log/fornax &
% clog /mnt/consoles/bootes /sys/log/bootes &
FILES
/srv/consoles Client end of pipe to server.
/mnt/consoles Default mount point.
/lib/ndb/consoledb Default user database.
SOURCE
/sys/src/cmd/aux/consolefs.c
/rc/bin/C
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CONSOLEFS(4) CONSOLEFS(4)
/sys/src/cmd/aux/clog.c
BUGS
Changing the gid's or uid's while consoelfs is running is
detected by consolefs. However, to add new consoles one must
restart consolefs.
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