Re: does numeric only name of jails not allowed (bug?)

On 8/9/25 11:10, Anthony Pankov wrote:
> Hello, Kyle.
> 
>>> 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.
> 
> For  me 47777 is a hexadecimal number (there is also a32b1 which works
> well).   I  want  it  to be the name of a jail (processed as a string)
> without any relation to jid.
> 
> But 47777 may  be recognized as a decimal number also and, consequently,
> will be used as a jid and a name.
> 

Consider posting your use-case to the freebsd-jail@ mailing list.  I 
don't know that a concession could be made here, the restriction is 
imposed at the kernel level and jail(8) is just the bearer of bad news. 
You would not have anymore luck trying to do this in C than you do with 
jail(8), unfortunately.


> 
> On 9 августа 2025 г., 16:30:32 you wrote:
> 
>> 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.
>>>
> 
>>>> 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.
>   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
>>>
>>>
>>>
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