acpid
Advanced Configuration and Power Interface event daemon
see also :
sh - acpi_listen
Synopsis
acpid
[options]
add an example, a script, a trick and tips
examples
description
acpid is
designed to notify user-space programs of ACPI events.
acpid should be started during the system boot, and
will run as a background process, by default. It will open
an events file (/proc/acpi/event by default) and
attempt to read whole lines which represent ACPI events. If
the events file does not exist, acpid will attempt to
connect to the Linux kernel via the input layer and netlink.
When an ACPI event is received from one of these sources,
acpid will examine a list of rules, and execute the
rules that match the event. acpid will ignore all
incoming ACPI events if a lock file exists
(/var/lock/acpid by default).
Rules
are defined by simple configuration files. acpid will
look in a configuration directory (/etc/acpi/events
by default), and parse all regular files with names that
consist entirely of upper and lower case letters, digits,
underscores, and hyphens (similar to run-parts(8)). Each
file must define two things: an event and an
action. Any blank lines, or lines where the first
character is a hash (’#’) are ignored.
Extraneous lines are flagged as warnings, but are not fatal.
Each line has three tokens: the key, a literal equal sign,
and the value. The key can be up to 63 characters, and is
case-insensitive (but whitespace matters). The value can be
up to 511 characters, and is case and whitespace
sensitive.
The event value
is a regular expression (see regcomp(3)), against which
events are matched.
The action
value is a commandline, which will be invoked via
/bin/sh whenever an event matching the rule in
question occurs. The commandline may include shell-special
characters, and they will be preserved. The only special
characters in an action value are "%" escaped. The
string "%e" will be replaced by the literal text
of the event for which the action was invoked. This string
may contain spaces, so the commandline must take care to
quote the "%e" if it wants a single token. The
string "%%" will be replaced by a literal
"%". All other "%" escapes are reserved,
and will cause a rule to not load.
This feature
allows multiple rules to be defined for the same event
(though no ordering is guaranteed), as well as one rule to
be defined for multiple events. To force acpid to
reload the rule configuration, send it a SIGHUP.
In addition to
rule files, acpid also accepts connections on a UNIX
domain socket (/var/run/acpid.socket by default). Any
application may connect to this socket. Once connected,
acpid will send the text of all ACPI events to the
client. The client has the responsibility of filtering for
messages about which it cares. acpid will not close
the client socket except in the case of a SIGHUP or
acpid exiting.
For faster
startup, this socket can be passed in as stdin so that
acpid need not create the socket. In addition, if a
socket is passed in as stdin, acpid will not
daemonize. It will be run in foreground. This behavior is
provided to support systemd(1).
acpid
will log all of its activities, as well as the stdout and
stderr of any actions, to syslog.
All the default
files and directories can be changed with commandline
options.
When
troubleshooting acpid, it is important to be aware
that other parts of a system might be handling ACPI events.
systemd(1) is capable of handling the power switch
and various other events that are commonly handled by
acpid. See the description of HandlePowerKey in
logind.conf(5) for more. Some window managers also
take over acpid’s normal handling of the power
button and other events.
options
-c,
--confdir directory
This option changes the
directory in which acpid looks for rule configuration
files. Default is /etc/acpi/events.
-C,
--clientmax number
This option changes the maximum
number of non-root socket connections which can be made to
the acpid socket. Default is 256.
-d, --debug
This option increases the acpid debug level by
one. If the debug level is non-zero, acpid will run
in the foreground, and will log to stderr, in addition to
the regular syslog.
-e,
--eventfile filename
This option changes the event
file from which acpid reads events. Default is
/proc/acpi/event.
-n,
--netlink
This option forces acpid
to use the Linux kernel input layer and netlink interface
for ACPI events.
-f,
--foreground
This option keeps acpid
in the foreground by not forking at startup.
-l,
--logevents
This option tells acpid
to log information about all events and actions.
-L,
--lockfile filename
This option changes the lock
file used to stop event processing. Default is
/var/lock/acpid.
-g,
--socketgroup groupname
This option changes the group
ownership of the UNIX domain socket to which acpid
publishes events.
-m,
--socketmode mode
This option changes the
permissions of the UNIX domain socket to which acpid
publishes events. Default is 0666.
-s,
--socketfile filename
This option changes the name of
the UNIX domain socket which acpid opens. Default is
/var/run/acpid.socket.
-S,
--nosocket filename
This option tells acpid
not to open a UNIX domain socket. This overrides the
-s option, and negates all other socket options.
-p,
--pidfile filename
This option tells acpid
to use the specified file as its pidfile. If the file
exists, it will be removed and over-written. Default is
/var/run/acpid.pid.
-v,
--version
Print version information and
exit.
-h, --help
Show help and exit.
dependencies
acpid should work on any linux kernel released since 2003.
example
This example will shut down your system if you press the power
button.
Create a file named /etc/acpi/events/power that contains the
following:
event=button/power
action=/etc/acpi/power.sh "%e"
Then create a file named /etc/acpi/power.sh that contains the
following:
/sbin/shutdown -h now "Power button pressed"
Now, when acpid is running, a press of the power button
will cause the rule in /etc/acpi/events/power to trigger the
script in /etc/acpi/power.sh. The script will then shut down the
system.
files
/proc/acpi/event
/dev/input/event*
/etc/acpi/
/var/run/acpid.socket
/var/run/acpid.pid
/var/lock/acpid
bugs
There are no
known bugs. To file bug reports, see AUTHORS
below.
see also
regcomp,
sh , socket, connect, systemd, acpi_listen ,
kacpimon
authors
Ted Felix
(www.tedfelix.com)
Tim Hockin <thockin[:at:]hockin[:dot:]org>
Andrew Henroid