Date: Fri, 24 Jul 1998 16:07:04 -0700 From: Mike Smith <mike@smith.net.au> To: wjw@IAEhv.nl Cc: dfr@nlsystems.com (Doug Rabson), hackers@FreeBSD.ORG Subject: Re: SYSCTL ....... Message-ID: <199807242307.QAA00758@dingo.cdrom.com> In-Reply-To: Your message of "Fri, 24 Jul 1998 01:16:39 %2B0200." <199807232316.BAA06524@surf.IAE.nl>
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> => Last time I was daydreaming about sysctl, I thought that using SYSINIT > => functions to build the tree would be a good idea. This would have the > => benefit of trivially adding in sysctl variables in kernel modules loaded > => using KLD since it runs SYSINITs in the loaded modules. To support > => unloading modules, a method of automatically disconnecting variables > => defined by the module is needed. > > Intresting point. > I haven't thought about this point. I considered that once submitted OID's > are there for ever. But evaporating LKM's would case some access trouble. Correct. We should incorporate the simple structure reference counting implementation that Terry published a little while back (Terry, why is this not on your webpage?). When registering a node, it should be possible to supply an object against which a reference will be taken. In the case of an LKM, the module may not be unloaded without its reference count being zero. > The main issue here is that the data-structure is fully dynamical. And > follows the MIB idea: which has identifiers: > N^n or S^n > where N is either a number or S a string. Given a certain prefix: > a.b.c.d > of the sequence a.b.c.d.e then the element N_e and S_e have a fixed > matching relation. (Call each level a layer of hierachy in the nameing > space, or more compiler like: scope) > However if the sequence is: > w.x.y.z.e' > then again N_e' and S_e' are a matching pair. But there is no relation > between S_e and S_e', although N_e and N_e' can have the same value. > this disjunct relation also hold for all other relation which are part of > the OIDnodes e and e'. Save yourself some grief, and eliminate numeric OIDs. > The numeric sequences are more/most important entry for the structure. > This due to the idea have on SNMP-mib's. No, and very bad. Numeric OIDs should be supported for *legacy* nodes only. > Given the fact that one of the most common operators on a MIB-tree will be > get_next, I'm considering adding a UP-relation as well. This will make it > possible to get back to the one-higher node in the same tree. The ability to traverse, and also to best-guess restart a traversal from a node that no longer exists, is critical. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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