1.\" $NetBSD: access.9,v 1.1 1996/06/16 10:38:35 pk Exp $ 2.\" 3.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Paul Kranenburg. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 29.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.\" $FreeBSD$ 38.\" 39.Dd June 16, 1996 40.Dt KERNACC 9 41.Os 42.Sh NAME 43.Nm kernacc , 44.Nm useracc 45.Nd check memory regions for accessibility 46.Sh SYNOPSIS 47.In sys/types.h 48.In vm/vm.h 49.In vm/vm_extern.h 50.Ft int 51.Fn kernacc "caddr_t addr" "int len" "int rw" 52.Ft int 53.Fn useracc "caddr_t addr" "int len" "int rw" 54.Sh DESCRIPTION 55The 56.Fn kernacc 57and 58.Fn useracc 59functions check whether operations of the type specified in 60.Fa rw 61are permitted in the range of virtual addresses given by 62.Fa addr 63and 64.Fa len . 65The possible values of 66.Fa rw 67are any bitwise combination of 68.Dv VM_PROT_READ , 69.Dv VM_PROT_WRITE 70and 71.Dv VM_PROT_EXECUTE . 72.Fn kernacc 73checks addresses in the kernel address space, while 74.Fn useracc 75considers 76.Fa addr 77to represent an user space address. 78The process context to use for this 79operation is taken from the global variable 80.Va curproc . 81.Sh RETURN VALUES 82Both functions return boolean true if the type of access specified 83by 84.Fa rw 85is permitted. 86Otherwise boolean false is returned. 87.Sh BUGS 88The process pointer should be passed in as an argument to 89.Fn useracc . 90