cvs commit: src/usr.sbin/jexec jexec.8 jexec.c

Alexander Leidinger Alexander at
Tue May 27 14:56:46 UTC 2008

Quoting Frank Behrens <frank at> (from Mon, 26 May 2008  
20:48:23 +0200):

> The rc.conf jail framework also requires unique hostnames for jails,  
> because the jail-ids are
> write to /var/run.

On a related note: JIDs are not known in advance, so doing some rc.d  
stuff which associates a specific X with a jail is not easy. So for  
example the zfs feature to  assign a zfs filesystem to a jail is  
practiaclly useless at the moment for stuff which shall be available  
after a reboot without admin intervention (it is not guaranteed that  
the jails get the same JID again on reboot).

In I have a  
patch which also uses the hostname of a jail to allow access to  
/dev/io in the jail (if the admin of the host made it visible in the  
jail). If ZFS would use the hostname, it would make it more useful  
(but maybe we would need some magic in the jail code to notify ZFS  
about a new jail, I haven't checked how ZFS is working in this regard).

So basically we need some unique value which is handed out by the  
admin and doesn't change after a reboot. For me the hostname is a good  
approximation for this (my hostnames are unique, and I have full  
control over them).


	Fear of men.    Alexander @ PGP ID = B0063FE7       netchild @  : PGP ID = 72077137

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