mirror of
https://git.proxmox.com/git/systemd
synced 2025-05-29 10:01:12 +00:00
109 lines
4.2 KiB
Groff
109 lines
4.2 KiB
Groff
'\" t
|
|
.TH "SYSTEMD\&.DEVICE" "5" "" "systemd 219" "systemd.device"
|
|
.\" -----------------------------------------------------------------
|
|
.\" * Define some portability stuff
|
|
.\" -----------------------------------------------------------------
|
|
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
.\" http://bugs.debian.org/507673
|
|
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
|
|
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
.ie \n(.g .ds Aq \(aq
|
|
.el .ds Aq '
|
|
.\" -----------------------------------------------------------------
|
|
.\" * set default formatting
|
|
.\" -----------------------------------------------------------------
|
|
.\" disable hyphenation
|
|
.nh
|
|
.\" disable justification (adjust text to left margin only)
|
|
.ad l
|
|
.\" -----------------------------------------------------------------
|
|
.\" * MAIN CONTENT STARTS HERE *
|
|
.\" -----------------------------------------------------------------
|
|
.SH "NAME"
|
|
systemd.device \- Device unit configuration
|
|
.SH "SYNOPSIS"
|
|
.PP
|
|
\fIdevice\fR\&.device
|
|
.SH "DESCRIPTION"
|
|
.PP
|
|
A unit configuration file whose name ends in
|
|
"\&.device"
|
|
encodes information about a device unit as exposed in the sysfs/\fBudev\fR(7)
|
|
device tree\&.
|
|
.PP
|
|
This unit type has no specific options\&. See
|
|
\fBsystemd.unit\fR(5)
|
|
for the common options of all unit configuration files\&. The common configuration items are configured in the generic
|
|
"[Unit]"
|
|
and
|
|
"[Install]"
|
|
sections\&. A separate
|
|
"[Device]"
|
|
section does not exist, since no device\-specific options may be configured\&.
|
|
.PP
|
|
systemd will dynamically create device units for all kernel devices that are marked with the "systemd" udev tag (by default all block and network devices, and a few others)\&. This may be used to define dependencies between devices and other units\&. To tag a udev device, use
|
|
"TAG+="systemd""
|
|
in the udev rules file, see
|
|
\fBudev\fR(7)
|
|
for details\&.
|
|
.PP
|
|
Device units are named after the
|
|
/sys
|
|
and
|
|
/dev
|
|
paths they control\&. Example: the device
|
|
/dev/sda5
|
|
is exposed in systemd as
|
|
dev\-sda5\&.device\&. For details about the escaping logic used to convert a file system path to a unit name see
|
|
\fBsystemd.unit\fR(5)\&.
|
|
.SH "THE UDEV DATABASE"
|
|
.PP
|
|
The settings of device units may either be configured via unit files, or directly from the udev database (which is recommended)\&. The following udev device properties are understood by systemd:
|
|
.PP
|
|
\fISYSTEMD_WANTS=\fR, \fISYSTEMD_USER_WANTS=\fR
|
|
.RS 4
|
|
Adds dependencies of type
|
|
\fIWants\fR
|
|
from the device unit to all listed units\&. The first form is used by the system systemd instance, the second by user systemd instances\&. Those settings may be used to activate arbitrary units when a specific device becomes available\&.
|
|
.sp
|
|
Note that this and the other tags are not taken into account unless the device is tagged with the
|
|
"systemd"
|
|
string in the udev database, because otherwise the device is not exposed as a systemd unit (see above)\&.
|
|
.sp
|
|
Note that systemd will only act on
|
|
\fIWants\fR
|
|
dependencies when a device first becomes active\&. It will not act on them if they are added to devices that are already active\&. Use
|
|
\fISYSTEMD_READY=\fR
|
|
(see below) to influence on which udev event to trigger the dependencies\&.
|
|
.RE
|
|
.PP
|
|
\fISYSTEMD_ALIAS=\fR
|
|
.RS 4
|
|
Adds an additional alias name to the device unit\&. This must be an absolute path that is automatically transformed into a unit name\&. (See above\&.)
|
|
.RE
|
|
.PP
|
|
\fISYSTEMD_READY=\fR
|
|
.RS 4
|
|
If set to 0, systemd will consider this device unplugged even if it shows up in the udev tree\&. If this property is unset or set to 1, the device will be considered plugged if it is visible in the udev tree\&. This property has no influence on the behavior when a device disappears from the udev tree\&.
|
|
.sp
|
|
This option is useful to support devices that initially show up in an uninitialized state in the tree, and for which a
|
|
"changed"
|
|
event is generated the moment they are fully set up\&. Note that
|
|
\fISYSTEMD_WANTS=\fR
|
|
(see above) is not acted on as long as
|
|
\fISYSTEMD_READY=0\fR
|
|
is set for a device\&.
|
|
.RE
|
|
.PP
|
|
\fIID_MODEL_FROM_DATABASE=\fR, \fIID_MODEL=\fR
|
|
.RS 4
|
|
If set, this property is used as description string for the device unit\&.
|
|
.RE
|
|
.SH "SEE ALSO"
|
|
.PP
|
|
\fBsystemd\fR(1),
|
|
\fBsystemctl\fR(1),
|
|
\fBsystemd.unit\fR(5),
|
|
\fBudev\fR(7),
|
|
\fBsystemd.directives\fR(7)
|