mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-23 11:18:54 +00:00
313 lines
9.0 KiB
Groff
313 lines
9.0 KiB
Groff
.\" Copyright (c) 1993
|
|
.\" The Regents of the University of California. 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.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
|
|
.\"
|
|
.\" From: @(#)sysctl.8 8.1 (Berkeley) 6/6/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 10, 2002
|
|
.Dt SYSCTL 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm sysctl
|
|
.Nd get or set kernel state
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl bdehNnox
|
|
.Ar name Ns Op = Ns Ar value
|
|
.Ar ...
|
|
.Nm
|
|
.Op Fl bdehNnox
|
|
.Fl a
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility retrieves kernel state and allows processes with appropriate
|
|
privilege to set kernel state.
|
|
The state to be retrieved or set is described using a
|
|
.Dq Management Information Base
|
|
.Pq Dq MIB
|
|
style name, described as a dotted set of
|
|
components.
|
|
.Pp
|
|
The following options are available:
|
|
.Bl -tag -width indent
|
|
.It Fl A
|
|
Equivalent to
|
|
.Fl o a
|
|
(for compatibility).
|
|
.It Fl a
|
|
List all the currently available non-opaque values.
|
|
This option is ignored if one or more variable names are specified on
|
|
the command line.
|
|
.It Fl b
|
|
Force the value of the variable(s) to be output in raw, binary format.
|
|
No names are printed and no terminating newlines are output.
|
|
This is mostly useful with a single variable.
|
|
.It Fl d
|
|
Print the description of the variable instead of its value.
|
|
.It Fl e
|
|
Separate the name and the value of the variable(s) with
|
|
.Ql = .
|
|
This is useful for producing output which can be fed back to the
|
|
.Nm
|
|
utility.
|
|
This option is ignored if either
|
|
.Fl N
|
|
or
|
|
.Fl n
|
|
is specified, or a variable is being set.
|
|
.It Fl h
|
|
Format output for human, rather than machine, readability.
|
|
.It Fl N
|
|
Show only variable names, not their values.
|
|
This is particularly useful with shells that offer programmable
|
|
completion.
|
|
To enable completion of variable names in
|
|
.Xr zsh 1 ,
|
|
use the following code:
|
|
.Bd -literal -offset indent
|
|
listsysctls () { set -A reply $(sysctl -AN ${1%.*}) }
|
|
compctl -K listsysctls sysctl
|
|
.Ed
|
|
.Pp
|
|
To enable completion of variable names in
|
|
.Xr tcsh 1 ,
|
|
use:
|
|
.Pp
|
|
.Dl "complete sysctl 'n/*/`sysctl -Na`/'"
|
|
.It Fl n
|
|
Show only variable values, not their names.
|
|
This option is useful for setting shell variables.
|
|
For instance, to save the pagesize in variable
|
|
.Va psize ,
|
|
use:
|
|
.Pp
|
|
.Dl "set psize=`sysctl -n hw.pagesize`"
|
|
.It Fl o
|
|
Show opaque variables (which are normally suppressed).
|
|
The format and length are printed, as well as a hex dump of the first
|
|
sixteen bytes of the value.
|
|
.It Fl X
|
|
Equivalent to
|
|
.Fl x a
|
|
(for compatibility).
|
|
.It Fl x
|
|
As
|
|
.Fl o ,
|
|
but prints a hex dump of the entire value instead of just the first
|
|
few bytes.
|
|
.El
|
|
.Pp
|
|
The information available from
|
|
.Nm
|
|
consists of integers, strings, devices
|
|
.Pq Vt dev_t ,
|
|
and opaque types.
|
|
The
|
|
.Nm
|
|
utility
|
|
only knows about a couple of opaque types, and will resort to hexdumps
|
|
for the rest.
|
|
The opaque information is much more useful if retrieved by special
|
|
purpose programs such as
|
|
.Xr ps 1 ,
|
|
.Xr systat 1 ,
|
|
and
|
|
.Xr netstat 1 .
|
|
.Pp
|
|
Some of the variables which cannot be modified during normal system
|
|
operation can be initialized via
|
|
.Xr loader 8
|
|
tunables.
|
|
This can for example be done by setting them in
|
|
.Xr loader.conf 5 .
|
|
Please refer to
|
|
.Xr loader.conf 5
|
|
for more information on which tunables are available and how to set them.
|
|
.Pp
|
|
The string and integer information is summarized below.
|
|
For a detailed description of these variable see
|
|
.Xr sysctl 3 .
|
|
.Pp
|
|
The changeable column indicates whether a process with appropriate
|
|
privilege can change the value.
|
|
String, integer, and devices values can be set using
|
|
.Nm .
|
|
For device values,
|
|
.Ar value
|
|
can be specified as a character device special file name.
|
|
Special values
|
|
.Cm off
|
|
and
|
|
.Cm none
|
|
denote
|
|
.Dq no device .
|
|
.Bl -column security.bsd.unprivileged_read_msgbuf integerxxx
|
|
.It Sy "Name Type Changeable
|
|
.It "kern.ostype string no
|
|
.It "kern.osrelease string no
|
|
.It "kern.osrevision integer no
|
|
.It "kern.version string no
|
|
.It "kern.maxvnodes integer yes
|
|
.It "kern.maxproc integer no
|
|
.It "kern.maxprocperuid integer yes
|
|
.It "kern.maxfiles integer yes
|
|
.It "kern.maxfilesperproc integer yes
|
|
.It "kern.argmax integer no
|
|
.It "kern.securelevel integer raise only
|
|
.It "kern.hostname string yes
|
|
.It "kern.hostid integer yes
|
|
.It "kern.clockrate struct no
|
|
.It "kern.posix1version integer no
|
|
.It "kern.ngroups integer no
|
|
.It "kern.job_control integer no
|
|
.It "kern.saved_ids integer no
|
|
.It "kern.boottime struct no
|
|
.It "kern.domainname string yes
|
|
.It "kern.filedelay integer yes
|
|
.It "kern.dirdelay integer yes
|
|
.It "kern.metadelay integer yes
|
|
.It "kern.osreldate string no
|
|
.It "kern.bootfile string yes
|
|
.It "kern.corefile string yes
|
|
.It "kern.dumpdev dev_t yes
|
|
.It "kern.logsigexit integer yes
|
|
.It "security.bsd.suser_enabled integer yes
|
|
.It "security.bsd.see_other_uids integer yes
|
|
.It "security.bsd.unprivileged_proc_debug integer yes
|
|
.It "security.bsd.unprivileged_read_msgbuf integer yes
|
|
.It "vm.loadavg struct no
|
|
.It "hw.machine string no
|
|
.It "hw.model string no
|
|
.It "hw.ncpu integer no
|
|
.It "hw.byteorder integer no
|
|
.It "hw.physmem integer no
|
|
.It "hw.usermem integer no
|
|
.It "hw.pagesize integer no
|
|
.It "hw.floatingpoint integer no
|
|
.It "hw.machine_arch string no
|
|
.It "machdep.console_device dev_t no
|
|
.It "machdep.adjkerntz integer yes
|
|
.It "machdep.disable_rtc_set integer yes
|
|
.It "machdep.guessed_bootdev string no
|
|
.It "user.cs_path string no
|
|
.It "user.bc_base_max integer no
|
|
.It "user.bc_dim_max integer no
|
|
.It "user.bc_scale_max integer no
|
|
.It "user.bc_string_max integer no
|
|
.It "user.coll_weights_max integer no
|
|
.It "user.expr_nest_max integer no
|
|
.It "user.line_max integer no
|
|
.It "user.re_dup_max integer no
|
|
.It "user.posix2_version integer no
|
|
.It "user.posix2_c_bind integer no
|
|
.It "user.posix2_c_dev integer no
|
|
.It "user.posix2_char_term integer no
|
|
.It "user.posix2_fort_dev integer no
|
|
.It "user.posix2_fort_run integer no
|
|
.It "user.posix2_localedef integer no
|
|
.It "user.posix2_sw_dev integer no
|
|
.It "user.posix2_upe integer no
|
|
.It "user.stream_max integer no
|
|
.It "user.tzname_max integer no
|
|
.El
|
|
.Sh FILES
|
|
.Bl -tag -width ".In netinet/icmp_var.h" -compact
|
|
.It In sys/sysctl.h
|
|
definitions for top level identifiers, second level kernel and hardware
|
|
identifiers, and user level identifiers
|
|
.It In sys/socket.h
|
|
definitions for second level network identifiers
|
|
.It In sys/gmon.h
|
|
definitions for third level profiling identifiers
|
|
.It In vm/vm_param.h
|
|
definitions for second level virtual memory identifiers
|
|
.It In netinet/in.h
|
|
definitions for third level Internet identifiers and
|
|
fourth level IP identifiers
|
|
.It In netinet/icmp_var.h
|
|
definitions for fourth level ICMP identifiers
|
|
.It In netinet/udp_var.h
|
|
definitions for fourth level UDP identifiers
|
|
.El
|
|
.Sh EXAMPLES
|
|
For example, to retrieve the maximum number of processes allowed
|
|
in the system, one would use the following request:
|
|
.Pp
|
|
.Dl "sysctl kern.maxproc"
|
|
.Pp
|
|
To set the maximum number of processes allowed
|
|
per uid to 1000, one would use the following request:
|
|
.Pp
|
|
.Dl "sysctl kern.maxprocperuid=1000"
|
|
.Pp
|
|
The device used for crash dumps can be specified using:
|
|
.Pp
|
|
.Dl "sysctl kern.dumpdev=/dev/somedev"
|
|
.Pp
|
|
which is equivalent to
|
|
.Pp
|
|
.Dl "dumpon /dev/somedev"
|
|
.Pp
|
|
Information about the system clock rate may be obtained with:
|
|
.Pp
|
|
.Dl "sysctl kern.clockrate"
|
|
.Pp
|
|
Information about the load average history may be obtained with:
|
|
.Pp
|
|
.Dl "sysctl vm.loadavg"
|
|
.Pp
|
|
More variables than these exist, and the best and likely only place
|
|
to search for their deeper meaning is undoubtedly the source where
|
|
they are defined.
|
|
.Sh COMPATIBILITY
|
|
The
|
|
.Fl w
|
|
option has been deprecated and is silently ignored.
|
|
.Sh SEE ALSO
|
|
.Xr sysctl 3 ,
|
|
.Xr loader.conf 5 ,
|
|
.Xr sysctl.conf 5 ,
|
|
.Xr loader 8
|
|
.Sh HISTORY
|
|
A
|
|
.Nm
|
|
utility first appeared in
|
|
.Bx 4.4 .
|
|
.Pp
|
|
In
|
|
.Fx 2.2 ,
|
|
.Nm
|
|
was significantly remodeled.
|
|
.Sh BUGS
|
|
The
|
|
.Nm
|
|
utility presently exploits an undocumented interface to the kernel
|
|
sysctl facility to traverse the sysctl tree and to retrieve format
|
|
and name information.
|
|
This correct interface is being thought about for the time being.
|