way for determine VIMAGE feature

[Bjoern A. Zeeb]

On Sun, 9 Jan 2011, Brandon Gooch wrote:

> On Sun, Jan 9, 2011 at 9:17 AM, Subbsd <subbsd at gmail.com> wrote:
>> Hi
>>
>> is there any mechanism to find out from userland  is supports the
>> current kernel VIMAGE or not? something like 'sysctl
>> kern.features.vnet=1' ?
>> Thanks
>
> I've not been able to determine this either, but as it requires kernel
> re-configuration, I usually just know. In my scripts, I make sure and
> fail if the call to create a vnet jail fails:
>
> sh -c 'TEST=$(sudo jail -c vnet name=test host.hostname=test path=/) ;
> if [ $? = "1" ]; then echo "VIMAGE NOT AVAILABLE" ; exit 1 ; fi'

I would just go with jail -c vnet command=/usr/bin/true or something
along these liens for the pure test.  Otherwise you might end up with
a running jail, that you may not want unless you test it with the
complete command line.


> ...or something like that.
>
> There may be a better way, or perhaps there should be.

Or there will be if there isn't yet.  I remember I added a FEATURE()
macro somehere.  At least my dev machine already has it...

# sysctl -a kern.features
kern.features.compat_freebsd7: 1
kern.features.compat_freebsd6: 1
kern.features.compat_freebsd5: 1
kern.features.compat_freebsd4: 1
kern.features.vimage: 1			<<<
kern.features.posix_shm: 1
kern.features.ipsec_natt: 1
kern.features.ipsec: 1

/bz

-- 
Bjoern A. Zeeb                                 You have to have visions!
         <ks> Going to jail sucks -- <bz> All my daemons like it!
   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/jails.html