Date: Wed, 22 May 2002 16:14:21 +0000 From: Phil Pennock <pdp@nl.demon.net> To: FreeBSD-gnats-submit@FreeBSD.org Subject: docs/38426: extra manpage .Xr to locate relevant sysctl information Message-ID: <E17AYkn-000Oxh-00@samhain.noc.nl.demon.net>
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>Number: 38426 >Category: docs >Synopsis: extra manpage .Xr to locate relevant sysctl information >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-doc >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Wed May 22 09:20:01 PDT 2002 >Closed-Date: >Last-Modified: >Originator: Phil Pennock >Release: FreeBSD 4.5-RELEASE-p2 i386 >Organization: Thus Plc / Demon Internet Netherlands >Environment: System: FreeBSD samhain.noc.nl.demon.net 4.5-RELEASE-p2 FreeBSD 4.5-RELEASE-p2 #3: Tue Apr 16 19:28:41 GMT 2002 root@samhain.noc.nl.demon.net:/usr/src/sys/compile/SAMHAIN i386 >Description: Some kernel values are available through sysctl(8), but are read-only. By reading the kernel source, it's possible to trace back to the fact that a variable such as kern.ipc.nmbclusters can be derived from the kernel's boot-time environment. More digging around in manual-pages points to loader(8) and possible Forth programming. More investigation finally reveals that a simple variable assignment in /boot/loader.conf does the trick (and even samples in /boot/defaults/loader.conf). >How-To-Repeat: Try, from first principles, to figure out how to change kern.ipc.nmbclusters without building a new kernel. >Fix: This patch for src/sbin/sysctl.8 improves the chances of finding the information quickly: --- sysctl.8.orig Wed May 22 18:02:19 2002 +++ sysctl.8 Wed May 22 18:06:28 2002 @@ -128,6 +128,10 @@ and .Nm netstat . .Pp +Some of the variables which can not be modified during normal system +operation can be initialised from the kernel run-time environment, +instead of modifying the kernel itself. +.Pp The string and integer information is summarized below. For a detailed description of these variable see .Xr sysctl 3 . @@ -244,7 +248,8 @@ option has been deprecated and is silently ignored. .Sh SEE ALSO .Xr sysctl 3 , -.Xr sysctl.conf 5 +.Xr sysctl.conf 5 , +.Xr loader.conf 5 .Sh BUGS .Nm Sysctl presently exploits an undocumented interface to the kernel >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message
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