-
-udev - a userspace device manager
-
-For more information on the design, and structure of this project, see the
-files in the docs/ directory.
-
-To use:
-
-- You must be running a 2.6 version of the Linux kernel.
-
-- Your 2.6 kernel must have had CONFIG_HOTPLUG enabled when it was built.
-
-- Make sure sysfs is mounted at /sys. No other location is supported.
- You can mount it by running:
- mount -t sysfs none /sys
-
-- Make sure you integrate udev with your hotplug setup. There is a copy of
- the rules files for all major distros in the etc/udev folder. You may look
- there how others are doing it.
-
-- Make sure you integrate with the kernel hotplug events. Later versions of
- udev are able to listen directly to a netlink socket, older versions used
- udevsend to feed the udev daemon with the kernel event. The most basic
- setup to run udev is to let the kernel for the udev binary directly:
- echo "/sbin/udev" > /proc/sys/kernel/hotplug
-
- While this may work in some setups, it is not recommended to do. A recent
- kernel and udev version is able to operate with the event serializing daemon
- udevd, that makes sure, that no "remove" event will beat a "add" event for
- the same device.
-
-- Build the project:
- make
-
- Note:
- There are a number of different flags that you can use when building
- udev. They are as follows:
- prefix
- set this to the default root that you want udev to be
- installed into. This works just like the 'configure --prefix'
- script does. Default value is ''. Only override this if you
- really know what you are doing.
- USE_KLIBC
- if set to 'true', udev is built and linked against the
- included version of klibc. Default value is 'false'.
- USE_LOG
- if set to 'true', udev will emit messages to the syslog when
- it creates or removes device nodes. This is helpful to see
- what udev is doing. This is enabled by default. Note, if you
- are building udev against klibc it is recommended that you
- disable this option (due to klibc's syslog implementation.)
- USE_SELINUX
- if set to 'true', udev will be built with SELinux support
- enabled. This is disabled by default.
- DEBUG
- if set to 'true', debugging messages will be sent to the syslog
- as udev is run. Default value is 'false'.
- KERNEL_DIR
- If this is not set it will default to /lib/modules/`uname -r`/build
- This is used if USE_KLIBC=true to find the kernel include
- directory that klibc needs to build against. This must be set
- if you are not building udev while running a 2.6 kernel.
- EXTRAS
- if set, will build the "extra" helper programs as specified
- as listed (see below for an example.)
-
- So, if you want to build udev using klibc with debugging messages, you
- would do:
- make USE_KLIBC=true DEBUG=true
-
- If you want to build the udev helper program cdrom_id and scsi_id you
- would do:
- make EXTRAS="extras/cdrom_id extras/scsi_id"
-
- udev will follow the setting of the debug level in udev.conf. Adapt this
- value to see the debug in syslog.
-
-- Install the project:
- make install
-
- This will put the udev binaries in /sbin, create the and /etc/udev
- directories, and place the udev configuration files in /etc/udev/. You
- will probably want to edit the *.rules files to create custom naming
- rules. More info on how the config files are set up are contained in
- comments in the files, and is located in the documentation.
-
-- Add and remove devices from the system and marvel as nodes are created
- and removed in /dev based on the device types.
-
-- If you later get sick of it, uninstall it:
- make uninstall
-
-If nothing seems to happen, make sure your build worked properly by
-running the udev-test.pl script as root in the test/ subdirectory of the
-udev source tree. Running udevstart should populate an empty /dev
-directory. You may test, if a node is recreated after running udevstart.
-
-Development and documentation help is very much appreciated, see the TODO
-file for a list of things left to be done.
-
-Any comment/questions/concerns please let me and the other udev developers
-know by sending a message to the linux-hotplug-devel mailing list at:
- linux-hotplug-devel@lists.sourceforge.net
-
-greg k-h
-greg@kroah.com
+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 use udev these
+ days, the major ones make it mandatory 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.
+
+udev requires:
+ - 2.6 version of the Linux kernel
+
+ - the kernel must have sysfs, netlink, and hotplug enabled
+
+ - proc must be mounted on /proc
+
+ - sysfs must be mounted at /sys, no other location is supported
+
+ - udev creates and removes device nodes in /dev based on events
+ the kernel sends out on device discovery or removal
+
+ - during bootup /dev usually gets a tmpfs mounted which is populated scratch
+ by udev (created nodes don't survive a reboot, it always starts from scratch)
+
+ - 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 posible to hook into the event processing
+
+ - there is a copy of the rules files for all major distros in the etc/udev
+ directory (you may look there how others distros are doing it)
+
+Setting which are used for building udev:
+ prefix
+ set this to the default root that you want to use
+ Only override this if you really know what you are doing
+ DESTDIR
+ prefix for install target for package building
+ USE_LOG
+ if set to 'true', udev will emit messages to the syslog when
+ it creates or removes device nodes. This is helpful to see
+ what udev is doing. This is enabled by default. Note, if you
+ are building udev against klibc it is recommended that you
+ disable this option (due to klibc's syslog implementation.)
+ DEBUG
+ if set to 'true', verbose debugging messages will be compiled into
+ the udev binaries. Default value is 'false'.
+ 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 the
+ included version of klibc. Default value is 'false'.
+ KERNEL_DIR
+ If this is not set it will default to /lib/modules/`uname -r`/build
+ This is used if USE_KLIBC=true to find the kernel include
+ directory that klibc needs to build against. This must be set
+ if you are not building udev while running a 2.6 kernel.
+ EXTRAS
+ if set, will build the "extra" helper programs as specified
+ as listed (see below for an example.)
+
+if you want to build udev using klibc with debugging messages:
+ make USE_KLIBC=true DEBUG=true
+
+if you want to build the udev helper program cdrom_id and scsi_id:
+ make EXTRAS="extras/cdrom_id extras/scsi_id"
+
+Please direct any comment/question/concern to the linux-hotplug-devel mailing list at:
+ linux-hotplug-devel@lists.sourceforge.net
~ianmdlvl / elogind.git / blobdiff