-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
-
+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 src/shared/MurmurHash2.c which is Public Domain
+ - except src/shared/siphash24.c which is CC0 Public Domain
+ - except src/journal/lookup3.c which is Public Domain
+ - except src/udev/* which is (currently still) GPLv2, GPLv2+
+
+REQUIREMENTS:
+ Linux kernel >= 3.7
+ Linux kernel >= 3.8 for Smack support
+
+ Kernel Config Options:
+ CONFIG_DEVTMPFS
+ CONFIG_CGROUPS (it is OK to disable all controllers)
+ CONFIG_INOTIFY_USER
+ CONFIG_SIGNALFD
+ CONFIG_TIMERFD
+ CONFIG_EPOLL
+ CONFIG_NET
+ CONFIG_SYSFS
+ CONFIG_PROC_FS
+ CONFIG_FHANDLE (libudev, mount and bind mount handling)
+
+ udev will fail to work with the legacy sysfs layout:
+ CONFIG_SYSFS_DEPRECATED=n
+
+ Legacy hotplug slows down the system and confuses udev:
+ CONFIG_UEVENT_HELPER_PATH=""
+
+ Userspace firmware loading is not supported and should
+ be disabled in the kernel:
+ CONFIG_FW_LOADER_USER_HELPER=n
+
+ Some udev rules and virtualization detection relies on it:
+ CONFIG_DMIID
+
+ Support for some SCSI devices serial number retrieval, to
+ create additional symlinks in /dev/disk/ and /dev/tape:
+ CONFIG_BLK_DEV_BSG
+
+ Required for PrivateNetwork and PrivateDevices in service units:
+ CONFIG_NET_NS
+ CONFIG_DEVPTS_MULTIPLE_INSTANCES
+ Note that systemd-localed.service and other systemd units use
+ PrivateNetwork and PrivateDevices so this is effectively required.
+
+ Optional but strongly recommended:
+ CONFIG_IPV6
+ CONFIG_AUTOFS4_FS
+ CONFIG_TMPFS_XATTR
+ CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL
+ CONFIG_SECCOMP
+
+ Required for CPUShares in resource control unit settings
+ CONFIG_CGROUP_SCHED
+ CONFIG_FAIR_GROUP_SCHED
+
+ Required for CPUQuota in resource control unit settings
+ CONFIG_CFS_BANDWIDTH
+
+ For systemd-bootchart, several proc debug interfaces are required:
+ CONFIG_SCHEDSTATS
+ CONFIG_SCHED_DEBUG
+
+ For UEFI systems:
+ CONFIG_EFIVAR_FS
+ CONFIG_EFI_PARTITION
+
+ Note that kernel auditing is broken when used with systemd's
+ container code. When using systemd in conjunction with
+ containers, please make sure to either turn off auditing at
+ runtime using the kernel command line option "audit=0", or
+ turn it off at kernel compile time using:
+ CONFIG_AUDIT=n
+ If systemd is compiled with libseccomp support on
+ architectures which do not use socketcall() and where seccomp
+ is supported (this effectively means x86-64 and ARM, but
+ excludes 32-bit x86!), then nspawn will now install a
+ work-around seccomp filter that makes containers boot even
+ with audit being enabled. This works correctly only on kernels
+ 3.14 and newer though. TL;DR: turn audit off, still.
+
+ glibc >= 2.14
+ libcap
+ libmount >= 2.20 (from util-linux)
+ libseccomp >= 1.0.0 (optional)
+ libblkid >= 2.24 (from util-linux) (optional)
+ libkmod >= 15 (optional)
+ PAM >= 1.1.2 (optional)
+ libcryptsetup (optional)
+ libaudit (optional)
+ libacl (optional)
+ libselinux (optional)
+ liblzma (optional)
+ liblz4 >= 119 (optional)
+ libgcrypt (optional)
+ libqrencode (optional)
+ libmicrohttpd (optional)
+ libpython (optional)
+ libidn (optional)
+ gobject-introspection > 1.40.0 (optional)
+ elfutils >= 158 (optional)
+ make, gcc, and similar tools
+
+ During runtime, you need the following additional
+ dependencies:
+
+ util-linux >= v2.25 required
+ dbus >= 1.4.0 (strictly speaking optional, but recommended)
+ dracut (optional)
+ PolicyKit (optional)
+
+ When building from git, you need the following additional
+ dependencies:
+
+ pkg-config
+ docbook-xsl
+ xsltproc
+ automake
+ autoconf
+ libtool
+ intltool
+ gperf
+ gtkdocize (optional)
+ python (optional)
+ python-lxml (optional, but required to build the indices)
+ sphinx (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.
+
+ 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:
+
+ audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
+
+ 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. In addition, system
+ groups "wheel" and "adm" will be given read-only access to
+ journal files using systemd-tmpfiles.service.
+
+ 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.
+
+ Similarly, the NTP daemon requires the "systemd-timesync" system
+ user and group to exist.
+
+ Similarly, the network management daemon requires the
+ "systemd-network" system user and group to exist.
+
+ Similarly, the name resolution daemon requires the
+ "systemd-resolve" system user and group to exist.
+
+ Similarly, the kdbus dbus1 proxy daemon requires the
+ "systemd-bus-proxy" system user and group to exist.
+
+NSS:
+ systemd ships with three NSS modules:
+
+ nss-myhostname resolves the local hostname to locally
+ configured IP addresses, as well as "localhost" to
+ 127.0.0.1/::1.
+
+ nss-resolve enables DNS resolution via the systemd-resolved
+ DNS/LLMNR caching stub resolver "systemd-resolved".
+
+ nss-mymachines enables resolution of all local containers
+ registered with machined to their respective IP addresses.
+
+ To make use of these NSS modules, please add them to the
+ "hosts: " line in /etc/nsswitch.conf. The "resolve" module
+ should replace the glibc "dns" module in this file.
+
+ The three modules should be used in the following order:
+
+ hosts: files mymachines resolve myhostname
+
+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.
+
+ systemd requires that the /run mount point exists. systemd also
+ requires that /var/run is a a symlink to /run.
+
+ 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.
+
+ENGINEERING AND CONSULTING SERVICES:
+ ENDOCODE <https://endocode.com/> offers professional
+ engineering and consulting services for systemd. Please
+ contact Chris Kühl <chris@endocode.com> for more information.
~ianmdlvl / elogind.git / blobdiff