-udev - userspace device management
-
-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.
-
-Tools and rules shipped by udev are not public API and may change at any time.
-Never call any private tool in /lib/udev from any external application, it might
-just go away in the next release. Access to udev information is only offered
-by udevadm and libudev. Tools and rules in /lib/udev and the entire content of
-/dev/.udev/ is private to udev.
-
-Requirements:
- - Version 2.6.25 of the Linux kernel with sysfs, procfs, signalfd, inotify,
- unix domain sockets, networking and hotplug enabled:
- CONFIG_HOTPLUG=y
- CONFIG_UEVENT_HELPER_PATH=""
- CONFIG_NET=y
- CONFIG_UNIX=y
- CONFIG_SYSFS=y
- CONFIG_SYSFS_DEPRECATED*=n
- CONFIG_PROC_FS=y
- CONFIG_TMPFS=y
- CONFIG_INOTIFY=y
- CONFIG_SIGNALFD=y
- CONFIG_TMPFS_POSIX_ACL=y (user ACLs for device nodes)
- CONFIG_BLK_DEV_BSG=y (SCSI tape devices)
-
- - 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.
-
- - To build all udev extras, libacl, libglib2, libusb, usbutils, pciutils,
- gperf are needed. These dependencies can be disabled with the
- --disable-extras option.
-
-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
+systemd System and Service Manager
+DETAILS:
+ http://0pointer.de/blog/projects/systemd.html
+
+WEB SITE:
+ http://www.freedesktop.org/wiki/Software/systemd
+
+GIT:
+ git://anongit.freedesktop.org/systemd/systemd
+ ssh://git.freedesktop.org/git/systemd/systemd
+
+GITWEB:
+ http://cgit.freedesktop.org/systemd/systemd
+
+MAILING LIST:
+ http://lists.freedesktop.org/mailman/listinfo/systemd-devel
+ http://lists.freedesktop.org/mailman/listinfo/systemd-commits
+
+IRC:
+ #systemd on irc.freenode.org
+
+BUG REPORTS:
+ https://bugs.freedesktop.org/enter_bug.cgi?product=systemd
+
+AUTHOR:
+ Lennart Poettering
+ Kay Sievers
+ ...and many others
+
+LICENSE:
+ LGPLv2.1+ for all code
+ - except sd-daemon.[ch] and sd-readahead.[ch] which are MIT
+ - except src/udev/ which is GPLv2.0+
+
+REQUIREMENTS:
+ Linux kernel >= 2.6.39
+ with devtmpfs
+ with cgroups (but it's OK to disable all controllers)
+ optional but strongly recommended: autofs4, ipv6
+ dbus >= 1.4.0
+ libcap
+ PAM >= 1.1.2 (optional)
+ libcryptsetup (optional)
+ libaudit (optional)
+ libselinux (optional)
+ tcpwrappers (optional)
+
+ When you build from git you need the following additional dependencies:
+
+ docbook-xsl
+ xsltproc
+ automake
+ autoconf
+ libtool
+ gperf
+ make, gcc, and similar tools
+
+ During runtime you need the following dependencies:
+
+ util-linux > v2.18 (requires fsck -l, agetty -s)
+ sulogin (from sysvinit-tools, optional but recommended)
+ plymouth (optional)
+ dracut (optional)
+
+ When systemd-hostnamed is used it is strongly recommended to
+ install nss-myhostname to ensure that in a world of
+ dynamically changing hostnames the hostname stays resolveable
+ under all circumstances. In fact, systemd-hostnamed will warn
+ if nss-myhostname is not installed. Packagers are encouraged to
+ add a dependency on nss-myhostname to the package that
+ includes systemd-hostnamed.
+
+ Note that D-Bus can link against libsystemd-login.so, which
+ results in a cyclic build dependency. To accomodate for this
+ please build D-Bus without systemd first, then build systemd,
+ then rebuild D-Bus with systemd support.
+
+WARNINGS:
+ systemd will warn you during boot if /etc/mtab is not a
+ symlink to /proc/mounts. Please ensure that /etc/mtab is a
+ proper symlink.
+
+ systemd will warn you during boot if /usr is on a different
+ file system than /. While in systemd itself very little will
+ break if /usr is on a separate partition many of its
+ dependencies very likely will break sooner or later in one
+ form or another. For example udev rules tend to refer to
+ binaries in /usr, binaries that link to libraries in /usr or
+ binaries that refer to data files in /usr. Since these
+ breakages are not always directly visible systemd will warn
+ about this, since this kind of file system setup is not really
+ supported anymore by the basic set of Linux OS components.
+
+ For more information on this issue consult
+ http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
+
+ENGINEERING AND CONSULTING SERVICES:
+ ProFUSION <http://profusion.mobi> offers professional
+ engineering and consulting services for systemd for embedded
+ and other use. Please contact Gustavo Barbieri
+ <barbieri@profusion.mobi> for more information.
+
+ Disclaimer: This notice is not a recommendation or official
+ endorsement. However, ProFUSION's upstream work has been very
+ beneficial for the systemd project.
~ianmdlvl / elogind.git / blobdiff