X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=84ca3c0aeaaf078b3e7aa5700176dd78e2d9eb37;hp=f6d1ab525756f0175a470f6f305a77277bdf0bda;hb=7b17a7d72f5ba5ad838b19803534c56a46f3bce9;hpb=a6c5b514d8e698316c57a0cf5183fcd8a7bc6d26 diff --git a/README b/README index f6d1ab525..84ca3c0ae 100644 --- a/README +++ b/README @@ -1,76 +1,114 @@ -udev - userspace device management - -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. - -Tools and rules shipped by udev are not public API and may change at any time. -Never call any private tool in /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 /lib/udev, and the entire content of -the /dev/.udev directory is private to udev and does change whenever needed. - -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_INOTIFY=y - CONFIG_SIGNALFD=y - CONFIG_TMPFS_POSIX_ACL=y (user ACLs for device nodes) - CONFIG_BLK_DEV_BSG=y (SCSI devices) - - - For reliable operations, the kernel must not use the CONFIG_SYSFS_DEPRECATED* - option. - - - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module may work, - but it 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, - gperf 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 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. - - - 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 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 + PAM >= 1.1.2 (optional) + libcryptsetup (optional) + libgcrypt (optional) + libaudit (optional) + libacl (optional) + libselinux (optional) + liblzma (optional) + tcpwrappers (optional) + libgcrypt (optional) + libqrencode (optional) + libmicrohttpd (optional) + + When you build from git you need the following additional dependencies: + + docbook-xsl + xsltproc + automake + autoconf + libtool + intltool + gperf + gtkdocize (optional) + python (optional) + make, gcc, and similar tools + + During runtime you need the following dependencies: + + util-linux > v2.18 (requires fsck -l, agetty -s) + sulogin (from sysvinit-tools, optional but recommended) + dracut (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 resolveable + under all circumstances. In fact, systemd-hostnamed will warn + if nss-myhostname is not installed. Packagers are encouraged to + add a dependency on nss-myhostname to the package that + includes systemd-hostnamed. + + 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 + +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.