man/sysusers.d.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!--
   5   This file is part of systemd.
   6
   7   Copyright 2014 Lennart Poettering
   8
   9   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
  11   the Free Software Foundation; either version 2.1 of the License, or
  12   (at your option) any later version.
  13
  14   systemd is distributed in the hope that it will be useful, but
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  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   Lesser General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  21 -->
  22 <refentry id="sysusers.d">
  23
  24         <refentryinfo>
  25                 <title>sysusers.d</title>
  26                 <productname>systemd</productname>
  27
  28                 <authorgroup>
  29                         <author>
  30                                 <contrib>Developer</contrib>
  31                                 <firstname>Lennart</firstname>
  32                                 <surname>Poettering</surname>
  33                                 <email>lennart@poettering.net</email>
  34                         </author>
  35                 </authorgroup>
  36         </refentryinfo>
  37
  38         <refmeta>
  39                 <refentrytitle>sysusers.d</refentrytitle>
  40                 <manvolnum>5</manvolnum>
  41         </refmeta>
  42
  43         <refnamediv>
  44                 <refname>sysusers.d</refname>
  45                 <refpurpose>Declarative allocation of system users and groups</refpurpose>
  46         </refnamediv>
  47
  48         <refsynopsisdiv>
  49                 <para><filename>/usr/lib/sysusers.d/*.conf</filename></para>
  50         </refsynopsisdiv>
  51
  52         <refsect1>
  53                 <title>Description</title>
  54
  55                 <para><command>systemd-sysusers</command> uses the
  56                 files from <filename>/usr/lib/sysusers.d/</filename>
  57                 to create system users and groups at package
  58                 installation or boot time. This tool may be used for
  59                 allocating system users and groups only, it is not
  60                 useful for creating non-system users and groups, as it
  61                 accessed <filename>/etc/passwd</filename> and
  62                 <filename>/etc/group</filename> directly, bypassing
  63                 any more complex user database, for example any
  64                 database involving NIS or LDAP.</para>
  65
  66         </refsect1>
  67
  68         <refsect1>
  69                 <title>File Format</title>
  70
  71                 <para>Each file shall be named in the style of
  72                 <filename><replaceable>package</replaceable>.conf</filename>.</para>
  73
  74                 <para>All files are sorted by their filename in
  75                 lexicographic order, regardless of which of the
  76                 directories they reside in. If multiple files specify
  77                 the same user or group, the entry in the file with the
  78                 lexicographically earliest name will be applied, all
  79                 all other conflicting entries will be logged as
  80                 errors. Users and groups are
  81                 processed in the order they are listed.</para>
  82
  83                 <para>The file format is one line per user or group
  84                 containing name, ID and GECOS field description:</para>
  85
  86                 <programlisting># Type Name ID GECOS
  87 u httpd 440 "HTTP User"
  88 u authd /usr/bin/authd "Authorization user"
  89 g input - -
  90 m authd input</programlisting>
  91
  92                 <refsect2>
  93                         <title>Type</title>
  94
  95                         <para>The type consists of a single
  96                         letter. The following line types are
  97                         understood:</para>
  98
  99                         <variablelist>
 100                                 <varlistentry>
 101                                         <term><varname>u</varname></term>
 102                                         <listitem><para>Create a
 103                                         system user and group of the
 104                                         specified name should they not
 105                                         exist yet. The user's primary
 106                                         group will be set to the group
 107                                         bearing the same name. The
 108                                         user's shell will be set to
 109                                         <filename>/sbin/login</filename>,
 110                                         the home directory to
 111                                         <filename>/</filename>. The
 112                                         account will be created
 113                                         disabled, so that logins are
 114                                         not allowed.</para></listitem>
 115                                 </varlistentry>
 116
 117                                 <varlistentry>
 118                                         <term><varname>g</varname></term>
 119                                         <listitem><para>Create a
 120                                         system group of the specified
 121                                         name should it not exist
 122                                         yet. Note that
 123                                         <varname>u</varname>
 124                                         implicitly create a matching
 125                                         group. The group will be
 126                                         created with no password
 127                                         set.</para></listitem>
 128                                 </varlistentry>
 129
 130                                 <varlistentry>
 131                                         <term><varname>m</varname></term>
 132                                         <listitem><para>Add a user to
 133                                         a group. If the user or group
 134                                         are not existing yet, they
 135                                         will be implicitly
 136                                         created.</para></listitem>
 137                                 </varlistentry>
 138                         </variablelist>
 139                 </refsect2>
 140
 141                 <refsect2>
 142                         <title>Name</title>
 143
 144                         <para>The name field specifies the user or
 145                         group name. It should be be shorter than 31
 146                         characters and avoid any non-ASCII characters,
 147                         and not begin with a numeric character. It is
 148                         strongly recommended to pick user and group
 149                         names that are unlikely to clash with normal
 150                         users created by the administrator. A good
 151                         scheme to guarantee this is by prefixing all
 152                         system and group names with the underscore,
 153                         and avoiding too generic names.</para>
 154
 155                         <para>For <varname>m</varname> lines this
 156                         field should contain the user name to add to a
 157                         group.</para>
 158                 </refsect2>
 159
 160                 <refsect2>
 161                         <title>ID</title>
 162
 163                         <para>For <varname>u</varname> and
 164                         <varname>g</varname> the numeric 32bit UID or
 165                         GID of the user/group. Do not use IDs 65535 or
 166                         4294967295, as they have special placeholder
 167                         meanings. Specify "-" for automatic UID/GID
 168                         allocation for the user or
 169                         group. Alternatively, specify an absolute path
 170                         in the file system. In this case the UID/GID
 171                         is read from the path's owner/group. This is
 172                         useful to create users whose UID/GID match the
 173                         owners of pre-existing files (such as SUID or
 174                         SGID binaries).</para>
 175
 176                         <para>For <varname>m</varname> lines this
 177                         field should contain the group name to add to
 178                         a user to.</para>
 179                 </refsect2>
 180
 181                 <refsect2>
 182                         <title>GECOS</title>
 183
 184                         <para>A short, descriptive string for users to
 185                         be created, enclosed in quotation marks. Note
 186                         that this field may not contain colons.</para>
 187
 188                         <para>Only applies to lines of type
 189                         <varname>u</varname> and should otherwise be
 190                         left unset.</para>
 191                 </refsect2>
 192
 193         </refsect1>
 194
 195         <refsect1>
 196                 <title>See Also</title>
 197                 <para>
 198                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 199                         <citerefentry><refentrytitle>systemd-sysusers</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 200                 </para>
 201         </refsect1>
 202
 203 </refentry>