systemd/man/sysusers.d.html
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<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="sysusers.d"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sysusers.d — Declarative allocation of system users and groups</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><p><code class="filename">/usr/lib/sysusers.d/*.conf</code></p></div><div class="refsect1"><a name="idm140640894650496"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p><span class="command"><strong>systemd-sysusers</strong></span> uses the files from
<code class="filename">sysusers.d</code> 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
<code class="filename">/etc/passwd</code> and
<code class="filename">/etc/group</code> directly, bypassing any more
complex user databases, for example any database involving NIS or
LDAP.</p></div><div class="refsect1"><a name="idm140640894646336"></a><h2 id="Configuration Format">Configuration Format<a class="headerlink" title="Permalink to this headline" href="#Configuration%20Format"></a></h2><p>Each configuration file shall be named in the style of
<code class="filename"><em class="replaceable"><code>package</code></em>.conf</code> or
<code class="filename"><em class="replaceable"><code>package</code></em>-<em class="replaceable"><code>part</code></em>.conf</code>.
The second variant should be used when it is desirable to make it
easy to override just this part of configuration.</p><p>The file format is one line per user or group containing
name, ID, GECOS field description and home directory:</p><pre class="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</pre><div class="refsect2"><a name="idm140640894570208"></a><h3 id="Type">Type<a class="headerlink" title="Permalink to this headline" href="#Type"></a></h3><p>The type consists of a single letter. The following line
types are understood:</p><div class="variablelist"><dl class="variablelist"><dt id="u"><span class="term"><code class="varname">u</code></span><a class="headerlink" title="Permalink to this term" href="#u"></a></dt><dd><p>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
<code class="filename">/sbin/nologin</code>, the home directory to
the specified home directory, or <code class="filename">/</code> if
none is given. The account will be created disabled, so that
logins are not allowed.</p></dd><dt id="g"><span class="term"><code class="varname">g</code></span><a class="headerlink" title="Permalink to this term" href="#g"></a></dt><dd><p>Create a system group of the specified name
should it not exist yet. Note that <code class="varname">u</code>
implicitly create a matching group. The group will be
created with no password set.</p></dd><dt id="m"><span class="term"><code class="varname">m</code></span><a class="headerlink" title="Permalink to this term" href="#m"></a></dt><dd><p>Add a user to a group. If the user or group
are not existing yet, they will be implicitly
created.</p></dd><dt id="r"><span class="term"><code class="varname">r</code></span><a class="headerlink" title="Permalink to this term" href="#r"></a></dt><dd><p>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.</p></dd></dl></div></div><div class="refsect2"><a name="idm140640894707600"></a><h3 id="Name">Name<a class="headerlink" title="Permalink to this headline" href="#Name"></a></h3><p>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.</p><p>For <code class="varname">m</code> lines this field should contain
the user name to add to a group.</p><p>For lines of type <code class="varname">r</code> this field should
be set to "<code class="literal">-</code>".</p></div><div class="refsect2"><a name="idm140640894703632"></a><h3 id="ID">ID<a class="headerlink" title="Permalink to this headline" href="#ID"></a></h3><p>For <code class="varname">u</code> and <code class="varname">g</code> the
numeric 32bit UID or GID of the user/group. Do not use IDs 65535
or 4294967295, as they have special placeholder meanings.
Specify "<code class="literal">-</code>" 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).</p><p>For <code class="varname">m</code> lines this field should contain
the group name to add to a user to.</p><p>For lines of type <code class="varname">r</code> this field should
be set to a UID/GID range in the format
"<code class="literal">FROM-TO</code>" where both values are formatted as
decimal ASCII numbers. Alternatively, a single UID/GID may be
specified formatted as decimal ASCII numbers.</p></div><div class="refsect2"><a name="idm140640894697968"></a><h3 id="GECOS">GECOS<a class="headerlink" title="Permalink to this headline" href="#GECOS"></a></h3><p>A short, descriptive string for users to be created,
enclosed in quotation marks. Note that this field may not
contain colons.</p><p>Only applies to lines of type <code class="varname">u</code> and
should otherwise be left unset, or be set to
"<code class="literal">-</code>".</p></div><div class="refsect2"><a name="idm140640894695152"></a><h3 id="Home Directory">Home Directory<a class="headerlink" title="Permalink to this headline" href="#Home%20Directory"></a></h3><p>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.</p><p>Only applies to lines of type <code class="varname">u</code> and
should otherwise be left unset, or be set to
"<code class="literal">-</code>".</p></div></div><div class="refsection"><a name="confd"></a><h2>Configuration Directories and Precedence</h2><p>Configuration files are read from directories in
<code class="filename">/etc/</code>, <code class="filename">/run/</code>, and
<code class="filename">/usr/lib/</code>, in order of precedence.
Each configuration file in these configuration directories shall be named in
the style of <code class="filename"><em class="replaceable"><code>filename</code></em>.conf</code>.
Files in <code class="filename">/etc/</code> override files with the same name in
<code class="filename">/run/</code> and <code class="filename">/usr/lib/</code>. Files in
<code class="filename">/run/</code> override files with the same name in
<code class="filename">/usr/lib/</code>.</p><p>Packages should install their configuration files in
<code class="filename">/usr/lib/</code>. Files in <code class="filename">/etc/</code> are
reserved for the local administrator, who may use this logic to override the
configuration files installed by vendor packages. All configuration files
are sorted by their filename in lexicographic order, regardless of which of
the directories they reside in. If multiple files specify the same option,
the entry in the file with the lexicographically latest name will take
precedence. It is recommended to prefix all filenames with a two-digit number
and a dash, to simplify the ordering of the files.</p><p>If the administrator wants to disable a configuration file supplied by
the vendor, the recommended way is to place a symlink to
<code class="filename">/dev/null</code> in the configuration directory in
<code class="filename">/etc/</code>, with the same filename as the vendor
configuration file.</p></div><div class="refsect1"><a name="idm140640894683952"></a><h2 id="Idempotence">Idempotence<a class="headerlink" title="Permalink to this headline" href="#Idempotence"></a></h2><p>Note that <span class="command"><strong>systemd-sysusers</strong></span> will do
nothing if the specified users or groups already exist, so
normally there no reason to override
<code class="filename">sysusers.d</code> vendor configuration, except to
block certain users or groups from being created.</p></div><div class="refsect1"><a name="idm140640894681232"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="systemd-sysusers.html"><span class="citerefentry"><span class="refentrytitle">systemd-sysusers</span>(8)</span></a>
</p></div></div></body></html>