Date: Sun, 7 Jun 1998 14:30:10 +0200 (MET DST) From: Willem Jan Withagen <wjw@surf.IAEhv.nl> To: mike@smith.net.au Cc: current@FreeBSD.ORG Subject: Variant Link implementation (Was: Re: lorder problem: ....... ) Message-ID: <199806071230.OAA28150@surf.IAEhv.nl> In-Reply-To: <199806061759.KAA01286@antipodes.cdrom.com> References: <199806061827.OAA16010@khavrinen.lcs.mit.edu>
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In article <199806061759.KAA01286@antipodes.cdrom.com> you write: >> <<On Sat, 6 Jun 1998 15:23:58 +0200 (MET DST), Willem Jan Withagen <wjw@surf.IAEhv.nl> said: >> >> > I do not want to debate the actual implemented syntax. But comming from >> > Apollo Domain OS this "feature" was one the the first things I missed when >> > going to "real" Unix. So I would really find this an enhancement to FreeBSD. >> >> If we really wanted to get variant symlinks, I would suggest copying >> the already-fairly-well-known syntax of AFS, `@name_of_parameter'. As >> the metasyntactic variable suggests, these should be (a fairly small >> number of) parameters which hold system-wide. (Indeed, given the >> existence of the sysctlbyname interface in the kernel, one could >> simply kick them off in that direction.) > >Ok. I did actually look at how this could be implemented last time it >came up, and I think it would be *reasonably* straightforward. Can you come up with that scenario? I might be tempted to take a look at it and possibly try to implement it. But I need to make some time estimates if I ever will be able to finisch it. >Can you clarify the AFS syntax a little more? Is there a delimiter >around the 'name'? If not, are variant components only allowed to be >entire path entities? How do you put more than one entry based on a >single parameter into a given directory? Or are you forced to duplicate >information across more than one parameter? Syntax is in some ways a cosmetic issue. What we need next to syntax is the semantics of the variants. The easy way I once have thought of doing it, is in libc. (or atleast still in userspace) This way semantics are fairly easy and the sollution was doable. But I never got around to figuring out where it would kill things. (Dumb question: Does INIT have an environment which we can load?) Doing it thru sysctl-interogation has the advantage of the variables being global to all processes. It has the disadvantage that it is no longer local to one's process-space. --WjW -- Internet Access Eindhoven BV., voice: +31-40-2 393 393, data: +31-40-2 606 606 P.O. 928, 5600 AX Eindhoven, The Netherlands Full Internet connectivity for only fl 12.95 a month. Call now, and login as 'new'. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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