X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=19ed4468eab0806207bacf6f27dc3f606413789a;hp=ed25a733ab7ac5da0de8461efe1bc655b822c2c9;hb=916c5e4725ef4558b752c6464deef6492c8ac31a;hpb=bf3ca56fd4685a52ae66ed6ee05ec4705130b9fe diff --git a/README b/README index ed25a733a..19ed4468e 100644 --- a/README +++ b/README @@ -1,52 +1,77 @@ - -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. - -- 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 - -- 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, and it's a bit beyond proof of concept -code. 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 know. - -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