way for determine VIMAGE feature

[Bjoern A. Zeeb]

On Sun, 9 Jan 2011, Bjoern A. Zeeb wrote:

> 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

------------------------------------------------------------------------
Author: bz
Date: Sun Jan  9 20:40:21 2011
New Revision: 217203
URL: http://svn.freebsd.org/changeset/base/217203

Log:
   MfP4 CH=185246 [1]:

     Add FEATURE() to announce optional VIMAGE.

   MFC after:    3 days
   [1] for the moment put it in vnet.c.

Modified:
   head/sys/net/vnet.c

Modified: head/sys/net/vnet.c
==============================================================================
--- head/sys/net/vnet.c Sun Jan  9 17:40:04 2011        (r217202)
+++ head/sys/net/vnet.c Sun Jan  9 20:40:21 2011        (r217203)
@@ -80,6 +80,8 @@ __FBSDID("$FreeBSD$");
   *   stack instance.
   */

+FEATURE(vimage, "VIMAGE kernel virtualization");
+
  MALLOC_DEFINE(M_VNET, "vnet", "network stack control block");

  /*
------------------------------------------------------------------------

-- 
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