X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=b8d1f42e254676193c6aeacc1385d0d98e22bd3f;hp=fee078898cc2afaad3453bc8b22ceef18d810dcb;hb=23e97f7d9274b90fb0e1664945dc6259fdae6d39;hpb=c249f66a70f9ea623205f27f7931727acbafba9e diff --git a/README b/README index fee078898..b8d1f42e2 100644 --- a/README +++ b/README @@ -1,95 +1,185 @@ -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 depend on udev - these days 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. - -Requirements: - - 2.6 version of the Linux kernel. - - - The kernel must have sysfs, netlink, and hotplug enabled. - - - The proc filesystem must be mounted on /proc. - - - The sysfs filesystem must be mounted at /sys. No other location - is supported. - - -Operation: - - Udev creates and removes device nodes in /dev based on events - the kernel sends out on device discovery or removal - - - Directly after mounting the root filesystem, the udevd daemon must be - started by an init script. - - - From kernel version 2.6.15 on, the hotplug helper /sbin/hotplug should - be disabled with an init script before kernel modules are loaded. - - - During bootup, /dev usually gets a tmpfs filesystem mounted which is - populated from scratch by udev (created nodes don't survive a reboot, - the /lib/udev/devices directory should be used for "static nodes"). - - - 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 possible to hook into the event processing. - - - Copies of the rules files for all major distros are in the etc/udev - directory (you may look there how others distros are doing it). - -Compile Options: - prefix - Set this to the default root that you want to use only override - this if you really know what you are doing even then, you probably - don't do the right thing. - DESTDIR - Prefix for install target, used for package building. - USE_LOG - if set to 'true', udev is able to pass errors or debug information - to syslog. This is very useful to see what udev is doing or not doing, - it is enabled by default. - DEBUG - If set to 'true', very verbose debugging messages will be compiled - into the udev binaries. The actual level of debugging is specified - in the udev config file. - STRIPCMD - If udev is compiled for packaging an empty string can be passed - to disable the stripping of the binaries. - 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 klibc. - Default value is 'false'. KLCC specifies the klibc compiler - wrapper, usually located at /usr/bin/klcc. - EXTRAS - If set, will build the "extra" helper programs as specified - as listed (see below for an example). - -If you want to build the udev helper program cdrom_id and scsi_id: - make EXTRAS="extras/cdrom_id extras/scsi_id" - -Installation: - - The install target intall the udev binaries in the default locations, - all at boot time reqired binaries will be installed in /sbin. - - - The default location for scripts and binaries that are called from - rules is /lib/udev. - - - It is recommended to use the /lib/udev/devices directory to place - device nodes and symlinks in, which are copied to /dev at every boot. - That way, nodes for broken subsystems or devices which can't be - detected automatically by the kernel will always be available. - -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 sd-daemon.[ch] and sd-readahead.[ch] which are MIT + - except src/udev/ which is (currently still) GPLv2+ + +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 + + Linux kernel >= 3.8 for Smack support + + Udev will fail to work with the legacy layout: + CONFIG_SYSFS_DEPRECATED=n + + 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-', with + 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.