freebsd man page for kernacc

KERNACC(9)						   BSD Kernel Developer's Manual						KERNACC(9)

NAME
     kernacc, useracc -- check memory regions for accessibility

SYNOPSIS
     #include <sys/param.h>
     #include <sys/proc.h>
     #include <vm/vm.h>
     #include <vm/vm_extern.h>

     int
     kernacc(void *addr, int len, int rw);

     int
     useracc(void *addr, int len, int rw);

DESCRIPTION
     The kernacc() and useracc() functions check whether operations of the type specified in rw are permitted in the range of virtual addresses
     given by addr and len.  The possible values of rw are any bitwise combination of VM_PROT_READ, VM_PROT_WRITE and VM_PROT_EXECUTE.	kernacc()
     checks addresses in the kernel address space, while useracc() considers addr to represent an user space address.  The process context to use
     for this operation is taken from the global variable curproc.

RETURN VALUES
     Both functions return boolean true if the type of access specified by rw is permitted.  Otherwise boolean false is returned.

BUGS
     The process pointer should be passed in as an argument to useracc().

BSD
								   June 16, 1996							       BSD