-Elogind User, Seat and Session Manager
-
-Introduction
-------------
-
-Elogind is the systemd project's "logind", extracted out to be a
-standalone daemon. It integrates with PAM to know the set of users
-that are logged in to a system and whether they are logged in
-graphically, on the console, or remotely. Elogind exposes this
-information via the standard org.freedesktop.login1 D-Bus interface,
-as well as through the file system using systemd's standard
-/run/systemd layout. Elogind also provides "libelogind", which is a
-subset of the facilities offered by "libsystemd". There is a
-"libelogind.pc" pkg-config file as well.
-
-All of the credit for elogind should go to the systemd developers.
-For more on systemd, see
-http://www.freedesktop.org/wiki/Software/systemd. All of the blame
-should go to Andy Wingo, who extracted elogind from systemd.
-
-Contributing
-------------
-
-Elogind was branched from systemd version 219, and preserves the git
-history of the systemd project. The version of elogind is the
-upstream systemd version, followed by the patchlevel of elogind. For
-example version 219.12 is the twelfth elogind release, which aims to
-provide a subset of the interfaces of systemd 219.
-
-To contribute to elogind, fork the current source code from github:
-
- https://github.com/elogind/elogind
-
-Send a pull request for the changes you like.
-
-To chat about elogind:
-
- #guix on irc.freenode.org
-
-Finally, bug reports:
-
- https://github.com/elogind/elogind/issues
-
-Why bother?
------------
-
-Elogind has been developed for use in GuixSD, the OS distribution of
-GNU Guix. See http://gnu.org/s/guix for more on Guix. GuixSD uses a
-specific init manager (DMD), for reasons that are not relevant here,
-but still aims to eventually be a full-featured distribution that can
-run GNOME and other desktop environments. However, to run GNOME these
-days means that you need to have support for the login1 D-Bus
-interface, which is currently only provided by systemd. That is the
-origin of this project: to take the excellent logind functionality
-from systemd and provide it as a standalone package.
-
-We like systemd. We realize that there are people out there that hate
-it. You're welcome to use elogind for whatever purpose you like --
-as-is, or as a jumping-off point for other things -- but please don't
-use it as part of some anti-systemd vendetta. Systemd hackers are
-smart folks that are trying to solve interesting problems on the free
-desktop, and their large adoption is largely because they solve
-problems that users and developers of user-focused applications care
-about. We are appreciative of their logind effort and think that
-everyone deserves to run it if they like, even if they use a different
-PID 1.
-
-Differences relative to systemd
--------------------------------
-
-The pkg-config file is called libelogind, not libsystemd or
-libsystemd-logind.
-
-The headers are in <elogind/...>, so like <elogind/sd-login.h> instead
-of <systemd/sd-login.h>.
-
-Libelogind just implements login-related functionality. It also
-provides the sd-bus API.
-
-Unlike systemd, whose logind arranges to manage resources for user
-sessions via RPC calls to systemd, in elogind there is no systemd so
-there is no global cgroup-based resource management. This has a few
-implications:
-
- * Elogind does not create "slices" for users. Elogind will not
- record that users are associated with slices.
-
- * The /run/systemd/slices directory will always be empty.
-
- * Elogind does not have the concept of a "scope", internally, as
- it's the same as a session. Any API that refers to scopes will
- always return an error code.
-
-On the other hand, elogind does use a similar strategy to systemd in
-that it places processes in a private cgroup for organizational
-purposes, without installing any controllers (see
-http://0pointer.de/blog/projects/cgroups-vs-cgroups.html). This
-allows elogind to map arbitrary processes to sessions, even if the
-process does the usual double-fork to be reparented to PID 1.
-
-Elogind does not manage virtual terminals.
-
-Elogind does monitor power button and the lid switch, like systemd,
-but instead of doing RPC to systemd to suspend, poweroff, or restart
-the machine, elogind just does this directly. For suspend, hybernate,
-and hybrid-sleep, elogind uses the same code as systemd-sleep.
-Instead of using a separate sleep.conf file to configure the sleep
-behavior, this is included in the [Sleep] section of
-/etc/elogind/login.conf. See the example login.conf for more. For
-shutdown, reboot, and kexec, elogind shells out to "halt", "reboot",
-and "kexec" binaries.
-
-The loginctl command has the poweroff, reboot, sleep, hibernate, and
-hybrid-sleep commands from systemd, as well as the --ignore-inhibitors
-flag.
-
-The PAM module is called pam_elogind.so, not pam_systemd.so.
-
-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
-
-Dependencies
-------------
-
- glibc >= 2.14
- libcap
- libmount >= 2.20 (from util-linux)
- libseccomp >= 1.0.0 (optional)
- libblkid >= 2.24 (from util-linux) (optional)
- PAM >= 1.1.2 (optional)
- libacl (optional)
- libselinux (optional)
- make, gcc, and similar tools
-
-During runtime, you need the following additional dependencies:
-
- dbus >= 1.4.0 (strictly speaking optional, but recommended)
- PolicyKit (optional)
-
-When building from git, you need the following additional
-dependencies:
-
- pkg-config
- docbook-xsl
- xsltproc
- automake
- autoconf
- libtool
- intltool
- gperf
- gtkdocize (optional)
+systemd System and Service Manager
+
+DETAILS:
+ http://0pointer.de/blog/projects/systemd.html
+
+WEB SITE:
+ http://www.freedesktop.org/wiki/Software/systemd
+
+GIT:
+ git@github.com:systemd/systemd.git
+ https://github.com/systemd/systemd.git
+
+GITWEB:
+ https://github.com/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://github.com/systemd/systemd/issues
+
+AUTHOR:
+ Lennart Poettering
+ Kay Sievers
+ ...and many others
+
+LICENSE:
+ LGPLv2.1+ for all code
+ - except src/basic/MurmurHash2.c which is Public Domain
+ - except src/basic/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 >= 3.11
+ Linux kernel >= 4.2 for unified cgroup hierarchy 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
+ CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
+
+ 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
+
+ We recommend to turn off Real-Time group scheduling in the
+ kernel when using systemd. RT group scheduling effectively
+ makes RT scheduling unavailable for most userspace, since it
+ requires explicit assignment of RT budgets to each unit whose
+ processes making use of RT. As there's no sensible way to
+ assign these budgets automatically this cannot really be
+ fixed, and it's best to disable group scheduling hence.
+ CONFIG_RT_GROUP_SCHED=n
+
+ 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 >= 2.16
+ 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)
+ elfutils >= 158 (optional)
+ make, gcc, and similar tools
+
+ During runtime, you need the following additional
+ dependencies:
+
+ util-linux >= v2.26 required
+ dbus >= 1.4.0 (strictly speaking optional, but recommended)
+ dracut (optional)
+ PolicyKit (optional)
+
+ When building from git, the following tools are needed:
+
+ pkg-config
+ docbook-xsl
+ xsltproc
+ automake
+ autoconf
+ libtool
+ intltool
+ gperf
+ python (optional)
+ python-lxml (optional, but required to build the indices)
+ sphinx (optional)
+
+ The build system is initialized with ./autogen.sh. A tar ball
+ can be created with:
+ git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
+
+ 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
+
+SYSV INIT.D SCRIPTS:
+ When calling "systemctl enable/disable/is-enabled" on a unit which is a
+ SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
+ this needs to translate the action into the distribution specific
+ mechanism such as chkconfig or update-rc.d. Packagers need to provide
+ this script if you need this functionality (you don't if you disabled
+ SysV init support).
+
+ Please see src/systemctl/systemd-sysv-install.SKELETON for how this
+ needs to look like, and provide an implementation at the marked places.
+
+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 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.
+
+ Currently, systemd-timesyncd defaults to use the Google NTP
+ servers if not specified otherwise at configure time. You
+ really should not ship an OS or device with this default
+ setting. See DISTRO_PORTING for details.
~ianmdlvl / elogind.git / blobdiff