-udev - userspace device management
+systemd System and Service Manager
-For more information see the files in the docs/ directory.
+DETAILS:
+ http://0pointer.de/blog/projects/systemd.html
-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.
+WEB SITE:
+ http://www.freedesktop.org/wiki/Software/systemd
-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.
+GIT:
+ git://anongit.freedesktop.org/systemd/systemd
+ ssh://git.freedesktop.org/git/systemd/systemd
- - The kernel must have sysfs, unix domain sockets and networking enabled.
- Unix domain sockets (CONFIG_UNIX) as a loadable kernel module is not
- supported.
+GITWEB:
+ http://cgit.freedesktop.org/systemd/systemd
- - The proc filesystem must be mounted on /proc/, the sysfs filesystem must
- be mounted at /sys/. No other locations are supported by udev.
+MAILING LIST:
+ http://lists.freedesktop.org/mailman/listinfo/systemd-devel
+ http://lists.freedesktop.org/mailman/listinfo/systemd-commits
- - 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 while no network is available.
+IRC:
+ #systemd on irc.freenode.org
-Operation:
- Udev creates and removes device nodes in /dev/, based on events the kernel
- sends out on device discovery or removal.
+BUG REPORTS:
+ https://bugs.freedesktop.org/enter_bug.cgi?product=systemd
- - 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.
+AUTHOR:
+ Lennart Poettering
+ Kay Sievers
+ ...and many others
- - 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.
+LICENSE:
+ LGPLv2.1+ for all code
+ - except sd-daemon.[ch] and sd-readahead.[ch] which are MIT
+ - except src/udev/ which is (currently still) GPLv2+
- - 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.
+REQUIREMENTS:
+ Linux kernel >= 2.6.39
+ CONFIG_DEVTMPFS
+ CONFIG_CGROUPS (it's OK to disable all controllers)
+ CONFIG_INOTIFY_USER
+ CONFIG_SIGNALFD
+ CONFIG_TIMERFD
+ CONFIG_EPOLL
+ CONFIG_NET
+ CONFIG_SYSFS
- - The udevd daemon must be started on bootup to receive netlink uevents
- from the kernel driver core.
+ Linux kernel >= 3.8 for Smack support
- - 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.
+ Udev will fail to work with the legacy layout:
+ CONFIG_SYSFS_DEPRECATED=n
-Please direct any comment/question/concern to the linux-hotplug mailing list at:
- linux-hotplug@vger.kernel.org
+ Legacy hotplug slows down the system and confuses udev:
+ CONFIG_UEVENT_HELPER_PATH=""
+ Userspace firmware loading is deprecated, will go away, and
+ sometimes causes problems:
+ CONFIG_FW_LOADER_USER_HELPER=n
+
+ Some udev rules and virtualization detection relies on it:
+ CONFIG_DMIID
+
+ Mount and bind mount handling might require it:
+ CONFIG_FHANDLE
+
+ Optional but strongly recommended:
+ CONFIG_IPV6
+ CONFIG_AUTOFS4_FS
+ CONFIG_TMPFS_POSIX_ACL
+ CONFIG_TMPFS_XATTR
+ CONFIG_SECCOMP
+
+ For systemd-bootchart a kernel with procfs support and several
+ proc output options enabled is required:
+ CONFIG_PROC_FS
+ CONFIG_SCHEDSTATS
+ CONFIG_SCHED_DEBUG
+
+ For UEFI systems:
+ CONFIG_EFI_VARS
+ CONFIG_EFI_PARTITION
+
+ dbus >= 1.4.0
+ libcap
+ libblkid >= 2.20 (from util-linux) (optional)
+ libkmod >= 5 (optional)
+ PAM >= 1.1.2 (optional)
+ libcryptsetup (optional)
+ libaudit (optional)
+ libacl (optional)
+ libattr (optional)
+ libselinux (optional)
+ liblzma (optional)
+ tcpwrappers (optional)
+ libgcrypt (optional)
+ libqrencode (optional)
+ libmicrohttpd (optional)
+ libpython (optional)
+ make, gcc, and similar tools
+
+ During runtime you need the following additional dependencies:
+
+ util-linux >= v2.19 (requires fsck -l, agetty -s)
+ sulogin (from util-linux >= 2.22 or sysvinit-tools, optional but recommended)
+ dracut (optional)
+ PolicyKit (optional)
+
+ When building from git you need the following additional dependencies:
+
+ docbook-xsl
+ xsltproc
+ automake
+ autoconf
+ libtool
+ intltool
+ gperf
+ gtkdocize (optional)
+ python (optional)
+ sphinx (optional)
+ python-lxml (entirely 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 resolvable
+ under all circumstances. In fact, systemd-hostnamed will warn
+ if nss-myhostname is not installed.
+
+ Note that D-Bus can link against libsystemd-login.so, which
+ results in a cyclic build dependency. To accommodate for this
+ please build D-Bus without systemd first, then build systemd,
+ then rebuild D-Bus with systemd support.
+
+ To build HTML documentation for python-systemd using sphinx,
+ please first install systemd (using 'make install'), and then
+ invoke sphinx-build with 'make sphinx-<target>', with <target>
+ being 'html' or 'latexpdf'. If using DESTDIR for installation,
+ pass the same DESTDIR to 'make sphinx-html' invocation.
+
+USERS AND GROUPS:
+ Default udev rules use the following standard system group
+ names, which need to be resolvable by getgrnam() at any time,
+ even in the very early boot stages, where no other databases
+ and network are available:
+
+ tty, dialout, kmem, video, audio, lp, floppy, cdrom, tape, disk
+
+ During runtime the journal daemon requires the
+ "systemd-journal" system group to exist. New journal files will
+ be readable by this group (but not writable) which may be used
+ to grant specific users read access.
+
+ It is also recommended to grant read access to all journal
+ files to the system groups "wheel" and "adm" with a command
+ like the following in the post installation script of the
+ package:
+
+ # setfacl -nm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/
+
+ The journal gateway daemon requires the
+ "systemd-journal-gateway" system user and group to
+ exist. During execution this network facing service will drop
+ privileges and assume this uid/gid for security reasons.
+
+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
+
+ To run systemd under valgrind, compile with VALGRIND defined
+ (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
+ false positives will be triggered by code which violates
+ some rules but is actually safe.
~ianmdlvl / elogind.git / blobdiff