X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=3b248048cc557a7268032d43cec983883c505cc6;hp=0d25b84fad9f2c604ad83271c51572e49b6c7eb2;hb=f74e605fc06c1c23e968dc4c26045eb746791706;hpb=12a362be5c1982f80dbfb75bda070208a2c99cdf diff --git a/README b/README index 0d25b84fa..3b248048c 100644 --- a/README +++ b/README @@ -1,104 +1,120 @@ -udev - Linux userspace device management - -Integrating udev in the system has complex dependencies and may differ from -distribution to distribution. A system may not be able to boot up or work -reliably without a properly installed udev version. The upstream udev project -does not recommend replacing a distro's udev installation with the upstream -version. - -The upstream udev project's set of default rules may require a most recent -kernel release to work properly. This is currently version 2.6.32. - -Tools and rules shipped by udev are not public API and may change at any time. -Never call any private tool in /usr/lib/udev from any external application; it -might just go away in the next release. Access to udev information is only offered -by udevadm and libudev. Tools and rules in /usr/lib/udev and the entire contents -of the /run/udev directory are private to udev and do change whenever needed. - -Requirements: - - Version 2.6.34 of the Linux kernel with sysfs, procfs, signalfd, inotify, - unix domain sockets, networking and hotplug enabled - - - Some architectures might need a later kernel, that supports accept4(), - or need to backport the accept4() syscall wiring in the kernel. - - - These options are needed: - 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_INOTIFY_USER=y - CONFIG_SIGNALFD=y - - - These options might be needed: - CONFIG_TMPFS=y - CONFIG_TMPFS_POSIX_ACL=y (user ACLs for device nodes) - CONFIG_BLK_DEV_BSG=y (SCSI devices) - - - Udev does not work with the CONFIG_SYSFS_DEPRECATED* option. - - - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module may work, - but it is not supported. - - - The deprecated hotplug helper /sbin/hotplug should be disabled in the - kernel configuration, it is not needed today, and may render the system - unusable because the kernel may create too many processes in parallel - so that the system runs out-of-memory. - - - The proc filesystem must be mounted on /proc, and the sysfs filesystem must - be mounted at /sys. No other locations are supported by a standard - udev installation. - - - The default rule sset requires the following group names resolvable at udev startup: - disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, and kmem. - Especially in LDAP setups, it is required that getgrnam() be able to resolve - these group names with only the rootfs mounted and while no network is - available. - - - Some udev extras have external dependencies like: - libacl, libglib2, usbutils, pciutils, and gperf. - All these extras can be disabled with configure options. - -Setup: - - At bootup, the /dev directory should get the 'devtmpfs' filesystem - mounted. Udev manages the permissions and ownership of the kernel-created - device nodes, and udev possibly creates additional symlinks. If needed, udev also - works on an empty 'tmpfs' filesystem, but some device nodes like - /dev/null, /dev/console, /dev/kmsg should be created before udevd is started. - - - The udev daemon should be started to handle device events sent by the kernel. - During bootup, the events for already existing devices can be replayed, so - that they are configured by udev. This is usually done by: - udevadm trigger --action=add --type=subsystems - udevadm trigger --action=add --type=devices - - - Restarting the daemon never applies any rules to existing devices. - - - New/changed rule files are picked up automatically; there is no daemon - restart or signal needed. - -Operation: - - Based on events the kernel sends out on device creation/removal, udev - creates/removes device nodes and symlinks in the /dev directory. - - - All kernel events are matched against a set of specified rules, which - possibly hook into the event processing and load required kernel - modules to set up devices. For all devices, the kernel exports a major/minor - number; if needed, udev creates a device node with the default kernel - device name. If specified, udev applies permissions/ownership to the device - node, creates additional symlinks pointing to the node, and executes - programs to handle the device. - - - The events udev handles, and the information udev merges into its device - database, can be accessed with libudev: - http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/ - http://www.kernel.org/pub/linux/utils/kernel/hotplug/gudev/ - -For more details about udev and udev rules, see the udev man pages: - http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev/ - -Please direct any comment/question 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 GPLv2.0+ + +REQUIREMENTS: + Linux kernel >= 2.6.39 + with devtmpfs + with cgroups (but it's OK to disable all controllers) + optional but strongly recommended: autofs4, ipv6 + 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) + + When building from git you need the following additional dependencies: + + docbook-xsl + xsltproc + automake + autoconf + libtool + intltool + gperf + gtkdocize (optional) + python (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. + +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. + +ENGINEERING AND CONSULTING SERVICES: + ProFUSION offers professional + engineering and consulting services for systemd for embedded + and other use. Please contact Gustavo Barbieri + for more information. + + Disclaimer: This notice is not a recommendation or official + endorsement. However, ProFUSION's upstream work has been very + beneficial for the systemd project.