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: src/share/man/man9/kernacc.9,v 1.7.2.4 2001/12/17 11:30:18 ru Exp $ 38.\" $DragonFly: src/share/man/man9/kernacc.9,v 1.2 2003/06/17 04:37:01 dillon Exp $ 39.\" 40.Dd June 16, 1996 41.Dt KERNACC 9 42.Os 43.Sh NAME 44.Nm kernacc , 45.Nm useracc 46.Nd check memory regions for accessibility 47.Sh SYNOPSIS 48.In sys/types.h 49.In vm/vm.h 50.In vm/vm_extern.h 51.Ft int 52.Fn kernacc "caddr_t addr" "int len" "int rw" 53.Ft int 54.Fn useracc "caddr_t addr" "int len" "int rw" 55.Sh DESCRIPTION 56The 57.Fn kernacc 58and 59.Fn useracc 60functions check whether operations of the type specified in 61.Fa rw 62are permitted in the range of virtual addresses given by 63.Fa addr 64and 65.Fa len . 66The possible values of 67.Fa rw 68are any bitwise combination of 69.Dv VM_PROT_READ , 70.Dv VM_PROT_WRITE 71and 72.Dv VM_PROT_EXECUTE . 73.Fn kernacc 74checks addresses in the kernel address space, while 75.Fn useracc 76considers 77.Fa addr 78to represent an user space address. 79The process context to use for this 80operation is taken from the global variable 81.Va curproc . 82.Sh RETURN VALUES 83Both functions return boolean true if the type of access specified 84by 85.Fa rw 86is permitted. 87Otherwise boolean false is returned. 88.Sh BUGS 89The process pointer should be passed in as an argument to 90.Fn useracc . 91