DragonFlyBSD

Greetings.

First:
-c and -f aren't allowed to execute due to a wrong check in ktrace(1).
In FreeBSD it has been fixed:
http://svn.freebsd.org/viewvc/base?view=revision&revision=166679

Second:
ktrace_clear_callback(), which is applied on every process of the system,
doesn't check whether the X process is traced to a vnode. Therefore, if it isn't
traced, a NULL pointer dereference occurs when trying to access p->p_tracenode.

Patch in:
http://leaf.dragonflybsd.org/~beket/0001-Fix-ktrace-related-panic-with-c-f-flags.patch

Please review.

Best regards,
Stathis Kamperis