README: add udev goups

[thirdparty/systemd.git] / README

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)
        PolicyKit (optional)

        For systmed-bootchart a kernel with procfs support and several
        proc output options enabled is required:

        CONFIG_PROC_FS
        CONFIG_SCHEDSTATS
        CONFIG_SCHED_DEBUG

        When building from git you need the following additional dependencies:

        docbook-xsl
        xsltproc
        automake
        autoconf
        libtool
        intltool
        gperf
        gtkdocize (optional)
        python (optional)
        sphinx (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-<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 is
        available:
          tty, dialout, kmem, video, audio, lp, floppy, cdrom, tape, disk

        During runtime the journal daemon requires the
        "system-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/

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.