linux call_usermodehelper equivalent in freebsd?

James Thomason james at
Tue Apr 19 22:07:37 PDT 2005

>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?


It depends on what your user mode helper program is intended to do, 
but the traditional approach is to create a user mode program that 
blocks on a custom system call waiting for an event.  See the 
following 2001 freebsd-hackers thread from Terry Lambert, titled 
"Invoking a userland function from kernel" for further details and 
design considerations:


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