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Diffstat (limited to 'README')
| -rw-r--r-- | README | 182 |
1 files changed, 76 insertions, 106 deletions
@@ -1,107 +1,77 @@ - -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 |