linux call_usermodehelper equivalent in freebsd?

[Andrew Tappert]

I tried asking about this on freebsd-questions, but I didn't get a 
response and I gather this is a more appropriate forum.

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

Is there an equivalent in FreeBSD to the Linux kernel 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 (i.e., exec's a 
usermode program from the kernel), so I may see how it's properly done? 
  In what context is it ok just to do the exec?  How do I set it up?

Thanks,
Andrew