call_usermodehelper equivalent?

[Andrew Tappert]

This is a question about FreeBSD kernel (module) programming.

Is there an equivalent in FreeBSD to the Linux function 
'call_usermodehelper' which wraps execve to do as its name suggests, 
call a user mode helper program?  If there is, what is it?  If not, can 
some kind person please point me to some code in the kernel--if there is 
any--which does something similar, so I may see how it's properly done? 
  My searching thus far has been to no avail.

Thanks,
Andrew