1
0
mirror of https://github.com/systemd/systemd.git synced 2024-12-23 21:35:11 +03:00
The systemd System and Service Manager
Go to file
2009-06-09 22:47:48 +02:00
docs/writing_udev_rules doc: writing udev rules - refer to 'udevadm info' instead of 'udevinfo' 2009-01-24 15:24:01 +01:00
extras move syslog wrapper to libudev 2009-06-09 22:47:48 +02:00
libudev move syslog wrapper to libudev 2009-06-09 22:47:48 +02:00
m4 add m4/ subdir 2009-02-26 14:11:43 +01:00
rules path_id: delete old shell script 2009-06-08 16:51:13 +02:00
test test: check string substitutions in OWNER and GROUP 2009-05-22 20:54:46 +02:00
udev move syslog wrapper to libudev 2009-06-09 22:47:48 +02:00
.gitignore gitignore: move *.8 to subdirs 2008-09-29 05:03:43 +02:00
autogen.sh autogen.sh: add more warnings 2009-02-05 19:01:27 +01:00
ChangeLog release 142 2009-05-13 02:35:37 +02:00
configure.ac libudev: move to top-level directory 2009-06-08 21:36:06 +02:00
COPYING update source file headers 2006-08-28 00:29:11 +02:00
INSTALL update INSTALL 2008-08-28 22:58:03 +02:00
Makefile.am libudev: move to top-level directory 2009-06-08 21:36:06 +02:00
Makefile.am.inc fix libudev include in Makefile.am.in 2009-06-08 22:25:58 +02:00
NEWS udevd: convert to event worker processes 2009-06-04 01:44:04 +02:00
README udevd: convert to event worker processes 2009-06-04 01:44:04 +02:00
TODO udevd: print error if worker dies unexpectedly 2009-06-08 17:16:48 +02:00
udev.conf udevadm: control - use getopt_long() 2008-09-03 21:56:47 +02:00

udev - userspace device management

For more information see the files in the docs/ directory.

Important Note:
  Integrating udev in the system has complex dependencies and differs from distro
  to distro. All major distros depend on udev these days and the system may not
  work without a properly installed version. The upstream udev project does not
  recommend to replace a distro's udev installation with the upstream version.

Requirements:
  - Version 2.6.25 of the Linux kernel with sysfs, procfs, signalfd, inotify,
    unix domain sockets, networking and hotplug enabled.

  - For reliable operation, the kernel must not use the CONFIG_SYSFS_DEPRECATED*
    option.

  - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module is not
    supported.

  - The proc filesystem must be mounted on /proc/, the sysfs filesystem must
    be mounted at /sys/. No other locations are supported by udev.

  - The system must have the following group names resolvable at udev startup:
      disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
    Especially in LDAP setups, it is required, that getgrnam() is able to resolve
    these group names with only the rootfs mounted, and while no network is
    available.

Operation:
  Udev creates and removes device nodes in /dev/, based on events the kernel
  sends out on device discovery or removal.

  - Early in the boot process, the /dev/ directory should get a 'tmpfs'
    filesystem mounted, which is maintained by udev. Created nodes or changed
    permissions will not survive a reboot, which is intentional.

  - The content of /lib/udev/devices/ directory which contains the nodes,
    symlinks and directories, which are always expected to be in /dev, should
    be copied over to the tmpfs mounted /dev, to provide the required nodes
    to initialize udev and continue booting.

  - The old hotplug helper /sbin/hotplug should be disabled in the kernel
    configuration, it is not needed, and may render the system unusable
    because of a fork-bombing behavior.

  - All kernel events are matched against a set of specified rules in
    /lib/udev/rules.d/ which make it possible to hook into the event
    processing to load required kernel modules and setup devices. For all
    devices the kernel exports a major/minor number, udev will create a
    device node with the default kernel name, or the one specified by a
    matching udev rule.

Please direct any comment/question/concern to the linux-hotplug mailing list at:
  linux-hotplug@vger.kernel.org