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Devin Teske
b4a465e566
Reviewed by: ziaee, kfv Differential Revision: https://reviews.freebsd.org/D59746
146 lines
3.3 KiB
Plaintext
146 lines
3.3 KiB
Plaintext
.\" Copyright (c) 2013-2026 Devin Teske <[email protected]>
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.\" Copyright (c) 2021-2026 Faraz Vahedi <[email protected]>
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.\"
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.\" SPDX-License-Identifier: BSD-2-Clause
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.\"
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.Dd August 2, 2026
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.Dt SYSCONF-SYSCTL 8
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.Os
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.Sh NAME
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.Nm "sysconf sysctl"
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.Nd configure boot-time sysctl.conf directives
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.Sh SYNOPSIS
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.Nm sysconf
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.Cm sysctl
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.Op Fl AcDeFinNqvVx
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.Op Fl j Ar jail | Fl R Ar dir
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.Op Fl f Ar file | Fl k Ar module
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.Ar name Ns Op Ns Oo +|- Oc Ns = Ns Ar value
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.Ar ...
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.Nm sysconf
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.Cm sysctl
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.Op Fl ADeFnNqvV
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.Op Fl f Ar file | Fl k Ar module
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.Fl a
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.Nm sysconf
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.Cm sysctl
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.Op Fl AaDinNq
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.Fl d
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.Op Ar name ...
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.Nm sysconf
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.Cm sysctl
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.Op Fl E
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.Op Fl k Ar module
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.Fl l | L
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.Sh DESCRIPTION
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The
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.Cm sysctl
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target of
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.Xr sysconf 8
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reads and modifies
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.Xr sysctl.conf 5
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configuration.
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Shared assignment syntax and options are documented in
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.Xr sysconf 8 ;
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multi-file write policy in
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.Xr sysconf-targets 8 .
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.Pp
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The stock file list is
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.Pa /etc/sysctl.conf ,
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.Pa /etc/sysctl.conf.local ,
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then
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.Pa /etc/sysctl.kld.d/ Ns Ar module Ns Pa .conf
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when
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.Fl k Ar module
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is given
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.Pq applied by Xr rc.subr 8 when the module loads .
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.Pp
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Values are quoted on write only when the value requires it
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.Pq embedded whitespace .
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.Pp
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When writing to the running system,
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each
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.Ar name Ns = Ns Ar value
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is validated against the kernel's sysctl tree first.
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An OID that cannot be set at run time
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.Pq non-leaf, read-only, or loader-only tunable
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is reported and skipped,
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while the remaining assignments are still applied.
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In particular,
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a loader-only tunable is reported as requiring the
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.Cm loader
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target instead
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.Pq see Xr sysconf-loader 8 .
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Numeric values are also checked against the OID's
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.Dv CTLTYPE
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.Po
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.Dv CTLTYPE_INT ,
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.Dv CTLTYPE_U64 ,
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and the other integer widths
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.Pc
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so an overflowing or non-numeric assignment cannot land in
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.Xr sysctl.conf 5
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and fail
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.Pq or apply truncated
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when
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.Xr sysctl 8
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loads the file at boot.
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.Pp
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An unknown OID
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.Pq often from a module that is not yet loaded
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is reported with a warning but still written,
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matching how
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.Xr init 8
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treats such lines in
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.Xr sysctl.conf 5 ;
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.Fl i
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and
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.Fl q
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suppress that warning.
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Validation is skipped entirely under
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.Fl R ,
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where the target system's kernel is not the running kernel.
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.Pp
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.Fl d
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descriptions for this target come from the running kernel
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.Pq as with Xr sysctl 8 Fl d ,
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not from a defaults file.
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.Sh FILES
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.Bl -tag -width "/etc/sysctl.conf.local" -compact
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.It Pa /etc/sysctl.conf
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Write target for new directives.
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.It Pa /etc/sysctl.conf.local
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Site-local overrides.
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.It Pa /etc/sysctl.kld.d/
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Module-specific drop-ins
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.Pq see Fl k .
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.El
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.Sh EXAMPLES
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.Dl sysconf sysctl kern.maxfiles=65536
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.Dl sysconf sysctl -F vfs.usermount
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.Dl sysconf sysctl -d kern.maxfiles
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.Dl sysconf sysctl -L
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.Dl sysconf sysctl -LE
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.Dl sysconf sysctl -k ipfw net.inet.ip.fw.verbose=1
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.Dl sysconf -x sysctl vfs.usermount
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.Dl sysconf -j www sysctl kern.ipc.somaxconn=1024
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.Pp
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An overflowing assignment is refused before the file is touched
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.Pq here an integer OID given a value beyond INT_MAX :
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.Pp
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.Dl sysconf sysctl security.bsd.see_other_uids=99999999999
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.Sh SEE ALSO
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.Xr sysctl.conf 5 ,
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.Xr sysconf 8 ,
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.Xr sysconf-loader 8 ,
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.Xr sysconf-targets 8 ,
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nm sysconf
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utility first appeared in
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.Fx 16.0 .
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.Sh AUTHORS
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.An Devin Teske Aq Mt [email protected]
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.An Faraz Vahedi Aq Mt [email protected]
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