X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=a14e5c0fcff04e40b81ab462d236aa12d99fab8e;hp=cd3628736fecd06804043b441e417fe83634e850;hb=93ee84ce079c472ef22403c86a3081324d6eef40;hpb=1aa8fdf779219d953633323b4206acadc8b8e37b diff --git a/README b/README index cd3628736..a14e5c0fc 100644 --- a/README +++ b/README @@ -9,40 +9,40 @@ Important Note: recommend to replace a distro's udev installation with the upstream version. Requirements: - - Version 2.6.22 of the Linux kernel for reliable operation of this release of - udev. The kernel must not use the CONFIG_SYSFS_DEPRECATED* option. + - Version 2.6.25 of the Linux kernel with sysfs, procfs, signalfd, inotify, + unix domain sockets, networking and hotplug enabled. - - The kernel must have sysfs, unix domain sockets and networking enabled. - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module is not + - 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 + 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 while no network is available. + 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. - - Very early in the boot process, the /dev/ directory should get a 'tmpfs' - filesystem mounted, which is populated from scratch by udev. Created nodes - or changed permissions will not survive a reboot, which is intentional. + - 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 on bootup, before - actions like loading kernel modules are taken, which may cause a lot of - events. - - - The udevd daemon must be started on bootup to receive netlink uevents - from the kernel driver core. + - 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