1.\" $NetBSD: fetch.9,v 1.2 1996/01/09 21:59:24 perry Exp $ 2.\" 3.\" Copyright (c) 1996 Jason R. Thorpe. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed by Kenneth Stailey. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed for the NetBSD Project 19.\" by Jason R. Thorpe. 20.\" 4. The name of the author may not be used to endorse or promote products 21.\" derived from this software without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 30.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" $FreeBSD$ 36.\" 37.Dd October 29, 2014 38.Dt FETCH 9 39.Os 40.Sh NAME 41.Nm fetch , 42.Nm fubyte , 43.Nm fuswintr , 44.Nm fuword , 45.Nm fuword16 , 46.Nm fuword32 , 47.Nm fuword64 , 48.Nm fueword , 49.Nm fueword32 , 50.Nm fueword64 51.Nd fetch data from user-space 52.Sh SYNOPSIS 53.In sys/types.h 54.In sys/systm.h 55.Ft int 56.Fn fubyte "volatile const void *base" 57.Ft long 58.Fn fuword "volatile const void *base" 59.Ft int 60.Fn fuword16 "volatile const void *base" 61.Ft int32_t 62.Fn fuword32 "volatile const void *base" 63.Ft int64_t 64.Fn fuword64 "volatile const void *base" 65.Ft long 66.Fn fueword "volatile const void *base" "long *val" 67.Ft int32_t 68.Fn fueword32 "volatile const void *base" "int32_t *val" 69.Ft int64_t 70.Fn fueword64 "volatile const void *base" "int64_t *val" 71.In sys/resourcevar.h 72.Ft int 73.Fn fuswintr "void *base" 74.Sh DESCRIPTION 75The 76.Nm 77functions are designed to copy small amounts of data from user-space 78of the current process. 79If read is successful, it is performed atomically. 80The data read must be naturally aligned. 81.Pp 82The 83.Nm 84routines provide the following functionality: 85.Bl -tag -width "fueword32()" 86.It Fn fubyte 87Fetches a byte of data from the user-space address 88.Pa base . 89The byte read is zero-extended into the results variable. 90.It Fn fuword 91Fetches a word of data (long) from the user-space address 92.Pa base . 93.It Fn fuword16 94Fetches 16 bits of data from the user-space address 95.Pa base . 96The half-word read is zero-extended into the results variable. 97.It Fn fuword32 98Fetches 32 bits of data from the user-space address 99.Pa base . 100.It Fn fuword64 101Fetches 64 bits of data from the user-space address 102.Pa base . 103.It Fn fuswintr 104Fetches a short word of data from the user-space address 105.Pa base . 106This function is safe to call during an interrupt context. 107.It Fn fueword 108Fetches a word of data (long) from the user-space address 109.Pa base 110and stores the result in the variable pointed by 111.Pa val . 112.It Fn fueword32 113Fetches 32 bits of data from the user-space address 114.Pa base 115and stores the result in the variable pointed by 116.Pa val . 117.It Fn fueword64 118Fetches 64 bits of data from the user-space address 119.Pa base 120and stores the result in the variable pointed by 121.Pa val . 122.El 123.Pp 124The callers of 125.Fn fuword , 126.Fn fuword32 127and 128.Fn fuword64 129functions cannot distinguish between -1 read from 130userspace and function failure. 131.Sh RETURN VALUES 132The 133.Fn fubyte , 134.Fn fuword , 135.Fn fuword16 , 136.Fn fuword32 , 137.Fn fuword64 , 138and 139.Fn fuswintr 140functions return the data fetched or -1 on failure. 141The 142.Fn fueword , 143.Fn fueword32 144and 145.Fn fueword64 146functions return 0 on success and -1 on failure. 147.Sh SEE ALSO 148.Xr copy 9 , 149.Xr store 9 150