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 opera

tions 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 con

text 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