1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
<?xml version="1.0" encoding="UTF-8"?>
<!--
SPDX-FileCopyrightText: 1997 , Luca Berra
SPDX-FileCopyrightText: 2001 - 2007, Tomasz Kłoczko
SPDX-FileCopyrightText: 2005 - 2006, Yuri Kozlov
SPDX-FileCopyrightText: 2005 - 2008, Nicolas François
SPDX-License-Identifier: BSD-3-Clause
-->
<!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='limits.5'>
<!-- $Id$ -->
<refentryinfo>
<author>
<firstname>Luca</firstname>
<surname>Berra</surname>
<contrib>Creation, 1997</contrib>
</author>
<author>
<firstname>Thomas</firstname>
<surname>Kłoczko</surname>
<email>kloczek@pld.org.pl</email>
<contrib>shadow-utils maintainer, 2000 - 2007</contrib>
</author>
<author>
<firstname>Nicolas</firstname>
<surname>François</surname>
<email>nicolas.francois@centraliens.net</email>
<contrib>shadow-utils maintainer, 2007 - now</contrib>
</author>
</refentryinfo>
<refmeta>
<refentrytitle>limits</refentrytitle>
<manvolnum>5</manvolnum>
<refmiscinfo class="sectdesc">File Formats and Configuration Files</refmiscinfo>
<refmiscinfo class="source">shadow-utils</refmiscinfo>
<refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
</refmeta>
<refnamediv id='name'>
<refname>limits</refname>
<refpurpose>resource limits definition</refpurpose>
</refnamediv>
<!-- body begins here -->
<refsect1 id='description'>
<title>DESCRIPTION</title>
<para>
The <emphasis remap='I'>limits</emphasis> file
(<filename>/etc/limits</filename> by default
or LIMITS_FILE defined <filename>config.h</filename>) describes
the resource limits you wish to impose. It should be owned by
root and readable by root account only.
</para>
<para>
By default no quota is imposed on 'root'. In fact, there is no way to
impose limits via this procedure to root-equiv accounts (accounts with
UID 0).
</para>
<para>Each line describes a limit for a user in the form:</para>
<para>
<emphasis remap='I'>user LIMITS_STRING</emphasis>
</para>
<para>or in the form:</para>
<para>
<emphasis remap='I'>@group LIMITS_STRING</emphasis>
</para>
<para>
The <emphasis>LIMITS_STRING</emphasis> is a string of a concatenated
list of resource limits. Each limit consists of a letter identifier
followed by a numerical limit.
</para>
<para>The valid identifiers are:</para>
<itemizedlist>
<listitem><para>A: max address space (KB)</para></listitem>
<listitem><para>C: max core file size (KB)</para></listitem>
<listitem><para>D: max data size (KB)</para></listitem>
<listitem><para>F: maximum file size (KB)</para></listitem>
<listitem><para>K: file creation mask, set by
<citerefentry>
<refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>.</para>
</listitem>
<listitem><para>I: max nice value (0..39 which translates to
20..-19)</para></listitem>
<listitem><para>L: max number of logins for this user</para></listitem>
<listitem><para>M: max locked-in-memory address space (KB)</para></listitem>
<listitem><para>N: max number of open files</para></listitem>
<listitem><para>O: max real time priority</para></listitem>
<listitem><para>P: process priority, set by
<citerefentry>
<refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>.</para>
</listitem>
<listitem><para>R: max resident set size (KB)</para></listitem>
<listitem><para>S: max stack size (KB)</para></listitem>
<listitem><para>T: max CPU time (MIN)</para></listitem>
<listitem><para>U: max number of processes</para></listitem>
</itemizedlist>
<para>
For example, <emphasis remap='I'>L2D2048N5</emphasis> is a valid
<emphasis>LIMITS_STRING</emphasis>. For reading convenience, the
following entries are equivalent:
</para>
<programlisting>
username L2D2048N5
username L2 D2048 N5
</programlisting>
<para>
Be aware that after <emphasis remap='I'>username</emphasis> the rest
of the line is considered a limit string, thus comments are not
allowed. An invalid limits string will be rejected (not considered) by
the <command>login</command> program.
</para>
<para>
The default entry is denoted by username "<emphasis>*</emphasis>". If
you have multiple <emphasis remap='I'>default</emphasis> entries in
your <emphasis>LIMITS_FILE</emphasis>, then the last one will be used
as the default entry.
</para>
<para>
The limits specified in the form "<replaceable>@group</replaceable>"
apply to the members of the specified
<replaceable>group</replaceable>.
</para>
<para>
If more than one line with limits for a user exist, only the first line for
this user will be considered.
</para>
<para>
If no lines are specified for a user, the last
<replaceable>@group</replaceable> line matching a group whose the
user is a member of will be considered, or the last line with
default limits if no groups contain the user.
</para>
<para>
To completely disable limits for a user, a single dash
"<emphasis>-</emphasis>" will do.
</para>
<para>
To disable a limit for a user, a single dash
"<replaceable>-</replaceable>" can be used instead of the numerical
value for this limit.
</para>
<para>
Also, please note that all limit settings are set PER LOGIN. They are
not global, nor are they permanent. Perhaps global limits will come,
but for now this will have to do ;)
</para>
</refsect1>
<refsect1 id='files'>
<title>FILES</title>
<variablelist>
<varlistentry>
<term><filename>/etc/limits</filename></term>
<listitem><para></para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>login</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>.
</para>
</refsect1>
</refentry>
|
