Date: Fri, 5 Aug 2005 16:44:17 +0000 From: "Thordur I. Bjornsson" <thib@mi.is> To: freebsd-hackers@freebsd.org Subject: Re: Checking sysctl values from within the kernel. Message-ID: <20050805164417.32edf853.thib@mi.is> In-Reply-To: <200508051101.33927.jhb@FreeBSD.org> References: <20050805005543.5bd947f2.thib@mi.is> <20050805145046.GB78669@dan.emsphone.com> <200508051101.33927.jhb@FreeBSD.org>
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On Fri, 5 Aug 2005 11:01:32 -0400 John Baldwin <jhb@FreeBSD.org> wrote: > On Friday 05 August 2005 10:50 am, Dan Nelson wrote: > > In the last episode (Aug 05), Thordur I. Bjornsson said: > > > If I want to check a sysctl value from within the kernel (e.g. an > > > KLD), should I use the system calls described in sysctl(3) ? > > > > > > If not, what is the propper way to do so ? > > > > Since most sysctls are direct mappings onto integer variables in the > > kernel, just check the variable directly. > > There's also a kernel_sysctl() function available in the kernel for > in-kernel access to sysctls. You might have to lookup the OID for a > given name yourself though. Actually, there's a > kernel_sysctlbyname() as well. > > -- > John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ > "Power Users Use the Power to Serve" = http://www.FreeBSD.org Ahh. Cool This is not in any manpage ... I'm trying to understand the first argument to kernel_systcl(), kernel_sysctl(struct thread *td, ... ) This thread, that it takes as an argument is this something that I need to worry about when writing KLD's or could I just pass a NULL pointer ? The proplem is that I do not know/understand how threading works in the kernel. I'll be lookin into that (although pointers are more then welcome ;) -- Thordur I. <bzthib@gmail.com> Humppa!
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