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().