ref: f42e53655e9a2a1b516326f6522fba88db59a81c
dir: /sys/man/4/consolefs/
.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 .