196 lines
6.4 KiB
XML
196 lines
6.4 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!--
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SPDX-FileCopyrightText: 1997 , Luca Berra
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SPDX-FileCopyrightText: 2001 - 2007, Tomasz Kłoczko
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SPDX-FileCopyrightText: 2005 - 2006, Yuri Kozlov
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SPDX-FileCopyrightText: 2005 - 2008, Nicolas François
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SPDX-License-Identifier: BSD-3-Clause
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-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!-- SHADOW-CONFIG-HERE -->
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]>
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<refentry id='limits.5'>
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<!-- $Id$ -->
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<refentryinfo>
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<author>
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<firstname>Luca</firstname>
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<surname>Berra</surname>
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<contrib>Creation, 1997</contrib>
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</author>
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<author>
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<firstname>Thomas</firstname>
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<surname>Kłoczko</surname>
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<email>kloczek@pld.org.pl</email>
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<contrib>shadow-utils maintainer, 2000 - 2007</contrib>
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</author>
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<author>
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<firstname>Nicolas</firstname>
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<surname>François</surname>
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<email>nicolas.francois@centraliens.net</email>
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<contrib>shadow-utils maintainer, 2007 - now</contrib>
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</author>
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</refentryinfo>
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<refmeta>
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<refentrytitle>limits</refentrytitle>
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<manvolnum>5</manvolnum>
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<refmiscinfo class="sectdesc">File Formats and Configuration Files</refmiscinfo>
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<refmiscinfo class="source">shadow-utils</refmiscinfo>
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<refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
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</refmeta>
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<refnamediv id='name'>
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<refname>limits</refname>
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<refpurpose>resource limits definition</refpurpose>
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</refnamediv>
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<!-- body begins here -->
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<refsect1 id='description'>
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<title>DESCRIPTION</title>
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<para>
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The <emphasis remap='I'>limits</emphasis> file
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(<filename>/etc/limits</filename> by default
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or LIMITS_FILE defined <filename>config.h</filename>) describes
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the resource limits you wish to impose. It should be owned by
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root and readable by root account only.
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</para>
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<para>
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By default no quota is imposed on 'root'. In fact, there is no way to
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impose limits via this procedure to root-equiv accounts (accounts with
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UID 0).
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</para>
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<para>Each line describes a limit for a user in the form:</para>
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<para>
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<emphasis remap='I'>user LIMITS_STRING</emphasis>
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</para>
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<para>or in the form:</para>
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<para>
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<emphasis remap='I'>@group LIMITS_STRING</emphasis>
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</para>
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<para>
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The <emphasis>LIMITS_STRING</emphasis> is a string of a concatenated
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list of resource limits. Each limit consists of a letter identifier
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followed by a numerical limit.
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</para>
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<para>The valid identifiers are:</para>
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<itemizedlist>
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<listitem><para>A: max address space (KB)</para></listitem>
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<listitem><para>C: max core file size (KB)</para></listitem>
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<listitem><para>D: max data size (KB)</para></listitem>
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<listitem><para>F: maximum file size (KB)</para></listitem>
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<listitem><para>K: file creation mask, set by
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<citerefentry>
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<refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum>
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</citerefentry>.</para>
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</listitem>
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<listitem><para>I: max nice value (0..39 which translates to
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20..-19)</para></listitem>
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<listitem><para>L: max number of logins for this user</para></listitem>
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<listitem><para>M: max locked-in-memory address space (KB)</para></listitem>
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<listitem><para>N: max number of open files</para></listitem>
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<listitem><para>O: max real time priority</para></listitem>
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<listitem><para>P: process priority, set by
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<citerefentry>
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<refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum>
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</citerefentry>.</para>
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</listitem>
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<listitem><para>R: max resident set size (KB)</para></listitem>
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<listitem><para>S: max stack size (KB)</para></listitem>
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<listitem><para>T: max CPU time (MIN)</para></listitem>
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<listitem><para>U: max number of processes</para></listitem>
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</itemizedlist>
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<para>
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For example, <emphasis remap='I'>L2D2048N5</emphasis> is a valid
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<emphasis>LIMITS_STRING</emphasis>. For reading convenience, the
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following entries are equivalent:
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</para>
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<programlisting>
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username L2D2048N5
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username L2 D2048 N5
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</programlisting>
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<para>
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Be aware that after <emphasis remap='I'>username</emphasis> the rest
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of the line is considered a limit string, thus comments are not
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allowed. An invalid limits string will be rejected (not considered) by
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the <command>login</command> program.
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</para>
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<para>
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The default entry is denoted by username "<emphasis>*</emphasis>". If
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you have multiple <emphasis remap='I'>default</emphasis> entries in
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your <emphasis>LIMITS_FILE</emphasis>, then the last one will be used
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as the default entry.
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</para>
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<para>
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The limits specified in the form "<replaceable>@group</replaceable>"
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apply to the members of the specified
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<replaceable>group</replaceable>.
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</para>
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<para>
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If more than one line with limits for a user exist, only the first line for
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this user will be considered.
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</para>
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<para>
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If no lines are specified for a user, the last
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<replaceable>@group</replaceable> line matching a group whose the
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user is a member of will be considered, or the last line with
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default limits if no groups contain the user.
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</para>
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<para>
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To completely disable limits for a user, a single dash
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"<emphasis>-</emphasis>" will do.
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</para>
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<para>
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To disable a limit for a user, a single dash
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"<replaceable>-</replaceable>" can be used instead of the numerical
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value for this limit.
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</para>
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<para>
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Also, please note that all limit settings are set PER LOGIN. They are
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not global, nor are they permanent. Perhaps global limits will come,
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but for now this will have to do ;)
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</para>
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</refsect1>
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<refsect1 id='files'>
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<title>FILES</title>
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<variablelist>
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<varlistentry>
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<term><filename>/etc/limits</filename></term>
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<listitem><para></para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id='see_also'>
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<title>SEE ALSO</title>
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<para>
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<citerefentry>
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<refentrytitle>login</refentrytitle><manvolnum>1</manvolnum>
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</citerefentry>,
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<citerefentry>
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<refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum>
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</citerefentry>,
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<citerefentry>
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<refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum>
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</citerefentry>.
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</para>
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</refsect1>
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</refentry>
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