mirror of
https://github.com/systemd/systemd.git
synced 2024-10-28 03:25:31 +03:00
96 lines
3.8 KiB
Plaintext
96 lines
3.8 KiB
Plaintext
udev - userspace device management
|
|
|
|
For more information see the files in the docs/ directory.
|
|
|
|
Important Note:
|
|
Integrating udev in the system is a whole lot of work, has complex dependencies
|
|
and differs a lot from distro to distro. All reasonable distros depend on udev
|
|
these days and the system will not work without it.
|
|
|
|
The upstream udev project does not support or recomend to replace a distro's udev
|
|
installation with the upstream version. The installation of a unmodified upstream
|
|
version may render your system unusable! There is no "default" setup or a set
|
|
of "default" rules provided by the upstream udev version.
|
|
|
|
Requirements:
|
|
- 2.6 version of the Linux kernel.
|
|
|
|
- The kernel must have sysfs, netlink, and hotplug enabled.
|
|
|
|
- The proc filesystem must be mounted on /proc.
|
|
|
|
- The sysfs filesystem must be mounted at /sys. No other location
|
|
is supported.
|
|
|
|
|
|
Operation:
|
|
- Udev creates and removes device nodes in /dev based on events
|
|
the kernel sends out on device discovery or removal
|
|
|
|
- Directly after mounting the root filesystem, the udevd daemon must be
|
|
started by an init script.
|
|
|
|
- From kernel version 2.6.15 on, the hotplug helper /sbin/hotplug should
|
|
be disabled with an init script before kernel modules are loaded.
|
|
|
|
- During bootup, /dev usually gets a tmpfs filesystem mounted which is
|
|
populated from scratch by udev (created nodes don't survive a reboot,
|
|
the /lib/udev/devices directory should be used for "static nodes").
|
|
|
|
- Udev replaces the hotplug event management invoked from /sbin/hotplug
|
|
by the udevd daemon, which receives the kernel events over netlink.
|
|
|
|
- All kernel events are matched against a set of specified rules which
|
|
make it possible to hook into the event processing.
|
|
|
|
- Copies of the rules files for all major distros are in the etc/udev
|
|
directory (you may look there how others distros are doing it).
|
|
|
|
Compile Options:
|
|
prefix
|
|
Set this to the default root that you want to use only override
|
|
this if you really know what you are doing even then, you probably
|
|
don't do the right thing.
|
|
DESTDIR
|
|
Prefix for install target, used for package building.
|
|
USE_LOG
|
|
if set to 'true', udev is able to pass errors or debug information
|
|
to syslog. This is very useful to see what udev is doing or not doing,
|
|
it is enabled by default.
|
|
DEBUG
|
|
If set to 'true', very verbose debugging messages will be compiled
|
|
into the udev binaries. The actual level of debugging is specified
|
|
in the udev config file.
|
|
STRIPCMD
|
|
If udev is compiled for packaging an empty string can be passed
|
|
to disable the stripping of the binaries.
|
|
USE_SELINUX
|
|
If set to 'true', udev will be built with SELinux support
|
|
enabled. This is disabled by default.
|
|
USE_KLIBC
|
|
If set to 'true', udev is built and linked against klibc.
|
|
Default value is 'false'. KLCC specifies the klibc compiler
|
|
wrapper, usually located at /usr/bin/klcc.
|
|
EXTRAS
|
|
If set, will build the "extra" helper programs as specified
|
|
as listed (see below for an example).
|
|
|
|
If you want to build the udev helper program cdrom_id and scsi_id:
|
|
make EXTRAS="extras/cdrom_id extras/scsi_id"
|
|
|
|
Installation:
|
|
- The install target intall the udev binaries in the default locations,
|
|
all at boot time reqired binaries will be installed in /sbin.
|
|
|
|
- The default location for scripts and binaries that are called from
|
|
rules is /lib/udev.
|
|
|
|
- It is recommended to use the /lib/udev/devices directory to place
|
|
device nodes and symlinks in, which are copied to /dev at every boot.
|
|
That way, nodes for broken subsystems or devices which can't be
|
|
detected automatically by the kernel will always be available.
|
|
|
|
Please direct any comment/question/concern to the linux-hotplug-devel mailing list at:
|
|
linux-hotplug-devel@lists.sourceforge.net
|
|
|