.\" Title: limits.conf
.\" Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.74.0
.\" Date: 10/27/2010
.\" Manual: Linux-PAM Manual
.\" Source: Linux-PAM Manual
.\" Language: English
.\"
.TH "LIMITS\&.CONF" "5" "10/27/2010" "Linux-PAM Manual" "Linux\-PAM Manual"
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..
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.\" * MAIN CONTENT STARTS HERE *
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.SH "Name"
limits.conf \- configuration file for the pam_limits module
.SH "DESCRIPTION"
.PP
The syntax of the lines is as follows:
.PP
\fI\fR
\fI\fR
\fI- \fR
\fI\fR
.PP
The fields listed above should be filled as follows:
.PP
\fB\fR
.RS 4
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
a username
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
a groupname, with
\fB@group\fR
syntax\&. This should not be confused with netgroups\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
the wildcard
\fB*\fR, for default entry\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
the wildcard
\fB%\fR, for maxlogins limit only, can also be used with
\fI%group\fR
syntax\&.
.RE
.RE
.PP
\fB\fR
.RS 4
.PP
\fBhard\fR
.RS 4
for enforcing
\fBhard\fR
resource limits\&. These limits are set by the superuser and enforced by the Kernel\&. The user cannot raise his requirement of system resources above such values\&.
.RE
.PP
\fBsoft\fR
.RS 4
for enforcing
\fBsoft\fR
resource limits\&. These limits are ones that the user can move up or down within the permitted range by any pre\-existing
\fBhard\fR
limits\&. The values specified with this token can be thought of as
\fIdefault\fR
values, for normal system usage\&.
.RE
.PP
\fB\-\fR
.RS 4
for enforcing both
\fBsoft\fR
and
\fBhard\fR
resource limits together\&.
.sp
Note, if you specify a type of \'\-\' but neglect to supply the item and value fields then the module will never enforce any limits on the specified user/group etc\&. \&.
.RE
.RE
.PP
\fB
- \fR
.RS 4
.PP
\fBcore\fR
.RS 4
limits the core file size (KB)
.RE
.PP
\fBdata\fR
.RS 4
maximum data size (KB)
.RE
.PP
\fBfsize\fR
.RS 4
maximum filesize (KB)
.RE
.PP
\fBmemlock\fR
.RS 4
maximum locked\-in\-memory address space (KB)
.RE
.PP
\fBnofile\fR
.RS 4
maximum number of open files
.RE
.PP
\fBrss\fR
.RS 4
maximum resident set size (KB) (Ignored in Linux 2\&.4\&.30 and higher)
.RE
.PP
\fBstack\fR
.RS 4
maximum stack size (KB)
.RE
.PP
\fBcpu\fR
.RS 4
maximum CPU time (minutes)
.RE
.PP
\fBnproc\fR
.RS 4
maximum number of processes
.RE
.PP
\fBas\fR
.RS 4
address space limit (KB)
.RE
.PP
\fBmaxlogins\fR
.RS 4
maximum number of logins for this user except for this with
\fIuid=0\fR
.RE
.PP
\fBmaxsyslogins\fR
.RS 4
maximum number of logins on system
.RE
.PP
\fBpriority\fR
.RS 4
the priority to run user process with (negative values boost process priority)
.RE
.PP
\fBlocks\fR
.RS 4
maximum locked files (Linux 2\&.4 and higher)
.RE
.PP
\fBsigpending\fR
.RS 4
maximum number of pending signals (Linux 2\&.6 and higher)
.RE
.PP
\fBmsqqueue\fR
.RS 4
maximum memory used by POSIX message queues (bytes) (Linux 2\&.6 and higher)
.RE
.PP
\fBnice\fR
.RS 4
maximum nice priority allowed to raise to (Linux 2\&.6\&.12 and higher) values: [\-20,19]
.RE
.PP
\fBrtprio\fR
.RS 4
maximum realtime priority allowed for non\-privileged processes (Linux 2\&.6\&.12 and higher)
.RE
.RE
.PP
All items support the values
\fI\-1\fR,
\fIunlimited\fR
or
\fIinfinity\fR
indicating no limit, except for
\fBpriority\fR
and
\fBnice\fR\&.
.PP
If a hard limit or soft limit of a resource is set to a valid value, but outside of the supported range of the local system, the system may reject the new limit or unexpected behavior may occur\&. If the control value
\fIrequired\fR
is used, the module will reject the login if a limit could not be set\&.
.PP
In general, individual limits have priority over group limits, so if you impose no limits for
\fIadmin\fR
group, but one of the members in this group have a limits line, the user will have its limits set according to this line\&.
.PP
Also, please note that all limit settings are set
\fIper login\fR\&. They are not global, nor are they permanent; existing only for the duration of the session\&.
.PP
In the
\fIlimits\fR
configuration file, the \'\fB#\fR\' character introduces a comment \- after which the rest of the line is ignored\&.
.PP
The pam_limits module does report configuration problems found in its configuration file and errors via
\fBsyslog\fR(3)\&.
.SH "EXAMPLES"
.PP
These are some example lines which might be specified in
\FC/etc/security/limits\&.conf\F[]\&.
.sp
.if n \{\
.RS 4
.\}
.fam C
.ps -1
.nf
.if t \{\
.sp -1
.\}
.BB lightgray adjust-for-leading-newline
.sp -1
* soft core 0
* hard rss 10000
@student hard nproc 20
@faculty soft nproc 20
@faculty hard nproc 50
ftp hard nproc 0
@student \- maxlogins 4
.EB lightgray adjust-for-leading-newline
.if t \{\
.sp 1
.\}
.fi
.fam
.ps +1
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.PP
\fBpam_limits\fR(8),
\fBpam.d\fR(5),
\fBpam\fR(8),
\fBgetrlimit\fR(2)
\fBgetrlimit\fR(3p)
.SH "AUTHOR"
.PP
pam_limits was initially written by Cristian Gafton