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Diffstat (limited to 'man/subgid.5.xml')
| -rw-r--r-- | man/subgid.5.xml | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/man/subgid.5.xml b/man/subgid.5.xml new file mode 100644 index 0000000..70c561c --- /dev/null +++ b/man/subgid.5.xml @@ -0,0 +1,146 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!-- + Copyright (c) 2013 Eric W. Biederman + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + 3. The name of the copyright holders or contributors may not be used to + endorse or promote products derived from this software without + specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ +<!-- SHADOW-CONFIG-HERE --> +]> +<refentry id='subgid.5'> + <refentryinfo> + <author> + <firstname>Eric</firstname> + <surname>Biederman</surname> + <contrib>Creation, 2013</contrib> + </author> + </refentryinfo> + <refmeta> + <refentrytitle>subgid</refentrytitle> + <manvolnum>5</manvolnum> + <refmiscinfo class="sectdesc">File Formats and Conversions</refmiscinfo> + <refmiscinfo class="source">shadow-utils</refmiscinfo> + <refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo> + </refmeta> + <refnamediv id='name'> + <refname>subgid</refname> + <refpurpose>the subordinate gid file</refpurpose> + </refnamediv> + + <refsect1 id='description'> + <title>DESCRIPTION</title> + <para> + Each line in <filename>/etc/subgid</filename> contains + a user name and a range of subordinate group ids that user + is allowed to use. + + This is specified with three fields delimited by colons + (<quote>:</quote>). + These fields are: + </para> + <itemizedlist mark='bullet'> + <listitem> + <para>login name or UID</para> + </listitem> + <listitem> + <para>numerical subordinate group ID</para> + </listitem> + <listitem> + <para>numerical subordinate group ID count</para> + </listitem> + </itemizedlist> + + <para> + This file specifies the group IDs that ordinary users can use, with + the <command>newgidmap</command> command, to configure gid mapping + in a user namespace. + </para> + + <para> + Multiple ranges may be specified per user. + </para> + + <para> + When large number of entries (10000-100000 or more) are defined in + <filename>/etc/subgid</filename>, parsing performance penalty will + become noticeable. In this case it is recommended to use UIDs + instead of login names. Benchmarks have shown speed-ups up to 20x. + </para> + + </refsect1> + + <refsect1 id='files'> + <title>FILES</title> + <variablelist> + <varlistentry> + <term><filename>/etc/subgid</filename></term> + <listitem> + <para>Per user subordinate group IDs.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><filename>/etc/subgid-</filename></term> + <listitem> + <para>Backup file for /etc/subgid.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1 id='see_also'> + <title>SEE ALSO</title> + <para> + <citerefentry> + <refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>newgidmap</refentrytitle><manvolnum>1</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>newuidmap</refentrytitle><manvolnum>1</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>newusers</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>subuid</refentrytitle><manvolnum>5</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>useradd</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>userdel</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>usermod</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum> + </citerefentry>. + </para> + </refsect1> +</refentry> |