Date: Fri, 12 Jul 2002 00:29:39 +0200 From: Cyrille Lefevre <cyrille.lefevre@laposte.net> To: Juan Francisco Rodriguez Hervella <jrh@it.uc3m.es> Cc: freebsd-net@FreeBSD.ORG Subject: Re: sysctl inferface question Message-ID: <20020711222939.GE21234@gits.dyndns.org> In-Reply-To: <3D2D9D4E.74A1B6F4@it.uc3m.es> References: <3D2D9D4E.74A1B6F4@it.uc3m.es>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Jul 11, 2002 at 04:59:26PM +0200, Juan Francisco Rodriguez Hervella wrote:
>
> I'm very confused with the sysctl internals.
>
> For example, looking at the kernel source code of FreeBSD, I've realized
>
> of the following:
>
> netinet/in_proco.c:
> SYSCTL_NODE(_net_inet6, IPPROTO_DIVERT, divert,
> CTLFLAG_RW, 0, "DIVERT");
> netinet/ip_divert.c:
> SYSCTL_DECL(_net_inet_divert);
> netinet/ip_divert.c:
> SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD,
> 0, 0,
> div_pcblist, "S,xinpcb", "List of active divert sockets");
>
> Isn't this redundant ? I mean, if there is a "SYSCTL_NODE", there is
> *no* need for having
> "SYSCTL_DECL" in "ip_divert.c"... I am wrong ?
to define a node (pcblist here), you have to declare the node
(_net_inet_divert here) you want attach it before.
> Also, I don't undertand the meaning of the "fmt" field....what is it for
> ? What's the
> meaning of "S,xinpcb" in the above example ?
the format strings isn't used by the kernel but is by the sysctl(1) command.
take a look around lines 556-589 (show_var) in /usr/src/sbin/sysctl/sysctl.c :
case 'S':
i = 0;
if (strcmp(fmt, "S,clockinfo") == 0)
func = S_clockinfo;
else if (strcmp(fmt, "S,timeval") == 0)
func = S_timeval;
else if (strcmp(fmt, "S,loadavg") == 0)
func = S_loadavg;
else if (strcmp(fmt, "T,dev_t") == 0)
func = T_dev_t;
else
func = NULL;
if (func) {
if (!nflag)
printf("%s%s", name, sep);
return ((*func)(len, p));
}
/* FALL THROUGH */
default:
if (!oflag && !xflag)
return (1);
if (!nflag)
printf("%s%s", name, sep);
printf("Format:%s Length:%d Dump:0x", fmt, len);
while (len-- && (xflag || p < val + 16))
printf("%02x", *p++);
if (!xflag && len > 16)
printf("...");
return (0);
so, the "S" is required, but, IMHO, ",xinpcb" is just informative for now.
# sysctl net.inet.divert
# sysctl net.inet.divert.pcblist
# sysctl -A net.inet.divert
net.inet.divert.pcblist: Format:S,xinpcb Length:336 Dump:0x18000000010000000100000000000000...
# sysctl -A net.inet.divert.pcblist
(same)
Cyrille.
--
Cyrille Lefevre mailto:cyrille.lefevre@laposte.net
12, Rue de Bizerte 75017 Paris http://clefevre.fr.st
tel/fax: +33 (0)1 45 22 83 85 gsm: +33 (0)6 80 94 76 63
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020711222939.GE21234>