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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<refentry id="sysusers.d" conditional='ENABLE_SYSUSERS'

xmlns:xi="http://www.w3.org/2001/XInclude">

<refentryinfo>

<title>sysusers.d</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>sysusers.d</refentrytitle>

<manvolnum>5</manvolnum>

</refmeta>

<refnamediv>

<refname>sysusers.d</refname>

<refpurpose>Declarative allocation of system users and groups</refpurpose>

</refnamediv>

<refsynopsisdiv>

<para><filename>/usr/lib/sysusers.d/*.conf</filename></para>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para><command>systemd-sysusers</command> uses the files from

<filename>sysusers.d</filename> directory to create system users

and groups at package installation or boot time. This tool may be

used to allocate system users and groups only, it is not useful

for creating non-system users and groups, as it accesses

<filename>/etc/passwd</filename> and

<filename>/etc/group</filename> directly, bypassing any more

complex user databases, for example any database involving NIS or

LDAP.</para>

</refsect1>

<refsect1>

<title>Configuration Format</title>

<para>Each configuration file shall be named in the style of

<filename><replaceable>package</replaceable>.conf</filename> or

<filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.

The second variant should be used when it is desirable to make it

easy to override just this part of configuration.</para>

<para>The file format is one line per user or group containing

name, ID, GECOS field description and home directory:</para>

<programlisting># Type Name ID GECOS

u httpd 440 "HTTP User"

u authd /usr/bin/authd "Authorization user"

g input - -

m authd input

u root 0 "Superuser" /root</programlisting>

<refsect2>

<title>Type</title>

<para>The type consists of a single letter. The following line

types are understood:</para>

<variablelist>

<varlistentry>

<term><varname>u</varname></term>

<listitem><para>Create a system user and group of the

specified name should they not exist yet. The user's primary

group will be set to the group bearing the same name. The

user's shell will be set to

<filename>/sbin/nologin</filename>, the home directory to

the specified home directory, or <filename>/</filename> if

none is given. The account will be created disabled, so that

logins are not allowed.</para></listitem>

</varlistentry>

<varlistentry>

<term><varname>g</varname></term>

<listitem><para>Create a system group of the specified name

should it not exist yet. Note that <varname>u</varname>

implicitly create a matching group. The group will be

created with no password set.</para></listitem>

</varlistentry>

<varlistentry>

<term><varname>m</varname></term>

<listitem><para>Add a user to a group. If the user or group

do not exist yet, they will be implicitly

created.</para></listitem>

</varlistentry>

<varlistentry>

<term><varname>r</varname></term>

<listitem><para>Add a range of numeric UIDs/GIDs to the pool

to allocate new UIDs and GIDs from. If no line of this type

is specified, the range of UIDs/GIDs is set to some

compiled-in default. Note that both UIDs and GIDs are

allocated from the same pool, in order to ensure that users

and groups of the same name are likely to carry the same

numeric UID and GID.</para></listitem>

</varlistentry>

</variablelist>

</refsect2>

<refsect2>

<title>Name</title>

<para>The name field specifies the user or group name. It should

be shorter than 31 characters and avoid any non-ASCII

characters, and not begin with a numeric character. It is

strongly recommended to pick user and group names that are

unlikely to clash with normal users created by the

administrator. A good scheme to guarantee this is by prefixing

all system and group names with the underscore, and avoiding too

generic names.</para>

<para>For <varname>m</varname> lines, this field should contain

the user name to add to a group.</para>

<para>For lines of type <varname>r</varname>, this field should

be set to <literal>-</literal>.</para>

</refsect2>

<refsect2>

<title>ID</title>

<para>For <varname>u</varname> and <varname>g</varname>, the

numeric 32-bit UID or GID of the user/group. Do not use IDs 65535

or 4294967295, as they have special placeholder meanings.

Specify <literal>-</literal> for automatic UID/GID allocation

for the user or group. Alternatively, specify an absolute path

in the file system. In this case, the UID/GID is read from the

path's owner/group. This is useful to create users whose UID/GID

match the owners of pre-existing files (such as SUID or SGID

binaries).</para>

<para>For <varname>m</varname> lines, this field should contain

the group name to add to a user to.</para>

<para>For lines of type <varname>r</varname>, this field should

be set to a UID/GID range in the format

<literal>FROM-TO</literal>, where both values are formatted as

decimal ASCII numbers. Alternatively, a single UID/GID may be

specified formatted as decimal ASCII numbers.</para>

</refsect2>

<refsect2>

<title>GECOS</title>

<para>A short, descriptive string for users to be created,

enclosed in quotation marks. Note that this field may not

contain colons.</para>

<para>Only applies to lines of type <varname>u</varname> and

should otherwise be left unset, or be set to

<literal>-</literal>.</para>

</refsect2>

<refsect2>

<title>Home Directory</title>

<para>The home directory for a new system user. If omitted,

defaults to the root directory. It is recommended to not

unnecessarily specify home directories for system users, unless

software strictly requires one to be set.</para>

<para>Only applies to lines of type <varname>u</varname> and

should otherwise be left unset, or be set to

<literal>-</literal>.</para>

</refsect2>

</refsect1>

<xi:include href="standard-conf.xml" xpointer="confd" />

<refsect1>

<title>Idempotence</title>

<para>Note that <command>systemd-sysusers</command> will do

nothing if the specified users or groups already exist, so

normally, there is no reason to override

<filename>sysusers.d</filename> vendor configuration, except to

block certain users or groups from being created.</para>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-sysusers</refentrytitle><manvolnum>8</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>