X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=b8d1f42e254676193c6aeacc1385d0d98e22bd3f;hp=3a511802eadbea08b3343c5303d938e4337e30aa;hb=c4aa09b06f835c91cea9e021df4c3605cff2318d;hpb=514b8d62123e3d63f2b935aa1d58e5c411f3f603 diff --git a/README b/README index 3a511802e..b8d1f42e2 100644 --- a/README +++ b/README @@ -1,70 +1,185 @@ -udev - userspace device management - -For more information see the files in the docs/ directory. - -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. - -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_TMPFS_POSIX_ACL=y - CONFIG_INOTIFY=y - CONFIG_SIGNALFD=y - - - 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 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 (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.