Date: Sat, 9 Aug 2025 08:30:32 -0500 From: Kyle Evans <kevans@FreeBSD.org> To: Anthony Pankov <anthony.pankov@yahoo.com>, freebsd-hackers@freebsd.org Subject: Re: does numeric only name of jails not allowed (bug?) Message-ID: <6f9509c7-d5df-47ee-9e98-db002bb5f84f@FreeBSD.org> In-Reply-To: <134128104.20250809140118@yahoo.com> References: <924624238.20250806173736@yahoo.com> <f7263091-4a3a-4aba-b168-74d75d77da0f@FreeBSD.org> <134128104.20250809140118@yahoo.com>
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On 8/9/25 06:01, Anthony Pankov wrote: > Hello Kyle, > >> This is an artifact of how numeric names work. When you use a purely numeric name, it's taken as both the jid and the name. jail(8) has some logic up-front that will set one or the other variable based on the name, but it omits the other. > > I think to prevent ambiguity there must be a possibility or requirement to quote jail name to force interpretation as a string. > Using "47777" instead of 47777 doesn't help for now. > What ambiguity are you referring to here? In context it's pretty unambiguous, the name is the thing that appears before an opening brace. >> When you use a purely numeric name, it's taken as both the jid > I've never hear about this feature. But I'm in doubt how to guarantee jail startup with jid=name=10 along system functioning. If non-numeric jail occupied jid 10 then jail 10 will not start? This is not new, jails have operated this way for 15+ years (since numeric names were first allowed). Indeed, if it's already occupied then the jail already exists and it will not start. > However, thinking of jid uniqueness in a wider area than localhost definitely leads us to use a bigger numbers. In such a case using hexadecimal format seems to be beneficial. Then there will be some code to interpret numeric names in decimal/hexadecimal format. So there will be some not so small branch of code for numeric jail name. And, again, to split this branch from pure string names I suggest to use name quotation to enforce string interpretation. > The kernel and jail(8) only do this for base 10 numbers; hex does not get resolved to base 10, and you end up with a jail that has a hex name and a jid allocated in the usual way. I'm not sure what else you're writing about here, because it's really not that complicated: if it coerces to a number in base 10 it's the jid, otherwise it's the name. Jails without a name use the jid as their name. This review will fix the bug I noted in my previous e-mail: https://reviews.freebsd.org/D51831 Thanks, Kyle Evans > > Friday, August 8, 2025, 8:24:32 PM, you wrote: > >> On 8/6/25 09:37, Anthony Pankov wrote: >>> Dear freebsd-hackers. >>>> It seems there is no sign that numeric only name is prohibited: >>>> " >>> The jail name. This is an arbitrary string that identifies a >>> jail (except it may not contain a ďż˝.ďż˝). >>> " >>>> But >>> # head jail-47777.conf >>> ... >>> 47777 { >>> host.hostname = "${name}"; >>> ... >>>> # jail -c 47777 >>> jail: 47777: host.hostname: variable "name" not found >>>> If I add letter prefix, say w47777, it worked. >>>> Because of strange error "variable "name" not found" it seems like a bug. Does it? >>> >> This is an artifact of how numeric names work. When you use a purely numeric name, it's taken as both the jid and the name. jail(8) has some logic up-front that will set one or the other variable based on the name, but it omits the other. > >> I have this almost fixed in 15.0, but trying your example I've found a bug in it -- setting the name, we need to use the string_param() of the KP_JID param as the `value`; the current use of KP_JID's cfparam for `p` to add_param() will adopt the name of KP_JID, which is a peculiarity that I wasn't aware of. > >> Thanks, > >> Kyle Evans > > >help
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