Ubuntu Manpage: acpid - Advanced Configuration and Power Interface event daemon

Provided by: acpid_2.0.21-1ubuntu2_amd64

NAME

       acpid - Advanced Configuration and Power Interface event daemon

SYNOPSIS

       acpid [options]

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.

The pseudo-action <drop> causes the event to be dropped completely and no further processing undertaken;
clients connecting via the UNIX domain socket (see below) will not be notified of the event. This may be
useful on some machines, such as certain laptops which generate spurious battery events at frequent
intervals. The name of this pseudo-action may be redefined with a commandline option.

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.

-r, --dropaction action
This option defines the pseudo-action which tells acpid to abort all processing of an event,
including client notifications. Default is <drop>.

-v, --version
Print version information and exit.

-h, --help Show help and exit.

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.

DEPENDENCIES

       acpid should work on any linux kernel released since 2003.

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 PROJECT WEBSITE below.

PROJECT WEBSITE

       http://sourceforge.net/projects/acpid2/

AUTHORS

       Ted Felix (ted -at- tedfelix -dot- com)
       Tim Hockin <thockin@hockin.org>
       Andrew Henroid

                                                                                                        acpid(8)