kern/45706: rnd ioctl changes break old userlands

[Taylor R Campbell <campbell+netbsd%mumble.net@localhost>]

>Number:         45706
>Category:       kern
>Synopsis:       rnd ioctl changes break old userlands
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Dec 10 22:35:00 +0000 2011
>Originator:     Taylor R Campbell <campbell+netbsd%mumble.net@localhost>
>Release:        NetBSD 5.99.56
>Organization:
>Environment:
System: NetBSD oberon.local 5.99.56 NetBSD 5.99.56 (RIAMONOHACK) #0: Sun Oct 16 
07:50:03 UTC 2011 
root@oberon.local:/home/riastradh/netbsd/current/obj/sys/arch/i386/compile/RIAMONOHACK
 i386
Architecture: i386
Machine: i386
>Description:

        The recent changes to the rnd(4) ioctls cause rndctl from old
        userlands to fail.  That means I can't upgrade to a new kernel
        without concurrently upgrading (partially) to a new userland
        and hosing my old kernel.

        I know this issue is mentioned in UPDATING, but really the
        issue shouldn't arise at all.

>How-To-Repeat:

        Try to boot from a new kernel.  Watch in horror as the cgd
        configuration at boot hangs.

>Fix:

        Add new rnd(4) ioctl commands instead of changing the semantics
        of the existing ones.