systemd-stable/README

udev - a userspace implementation of devfs

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.  udev will figure out where sysfs is mounted, but
  the traditional place for it is at /sys.  You can mount it by hand by running:
  	mount -t sysfs none /sys

- Make sure you have the latest version of the linux-hotplug scripts.  They are
  available at linux-hotplug.sf.net or from your local kernel.org mirror at:
	kernel.org/pub/linux/utils/kernel/hotplug/
  They are required in order for udev to work properly.

  If for some reason you do not install the hotplug scripts, you must tell the
  kernel to point the hotplug binary at wherever you install udev at.  This can
  be done by:
	echo "/sbin/udev" > /proc/sys/kernel/hotplug

- 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.

      So, if you want to build udev using klibc with debugging messages, you
      would do:
	make USE_KLIBC=true DEBUG=true

- Install the project:
	make install

  This will put the udev binary in /sbin, create the /udev and /etc/udev
  directories, and place the udev configuration files in /etc/udev.  You
  will probably want to edit the namedev.* 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 /udev/ based on the device types.

- If you later get sick of it, uninstall it:
	make uninstall


Things are still quite rough, but it should work properly.  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.

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