1 .\" $NetBSD: fetch.9,v 1.2 1996/01/09 21:59:24 perry Exp $
3 .\" Copyright (c) 1996 Jason R. Thorpe.
4 .\" All rights reserved.
6 .\" This code is derived from software contributed by Kenneth Stailey.
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9 .\" modification, are permitted provided that the following conditions
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18 .\" This product includes software developed for the NetBSD Project
19 .\" by Jason R. Thorpe.
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50 .Nd fetch data from user-space
55 .Fn fubyte "volatile const void *base"
57 .Fn fuword "volatile const void *base"
59 .Fn fuword16 "volatile const void *base"
61 .Fn fuword32 "volatile const void *base"
63 .Fn fuword64 "volatile const void *base"
65 .Fn fueword "volatile const void *base" "long *val"
67 .Fn fueword32 "volatile const void *base" "int32_t *val"
69 .Fn fueword64 "volatile const void *base" "int64_t *val"
73 functions are designed to copy small amounts of data from user-space
74 of the current process.
75 If the user address is naturally aligned, then the operation will be
77 Otherwise it may fail or be performed non-atomically, depending on
82 routines provide the following functionality:
83 .Bl -tag -width "fueword32()"
85 Fetches a byte of data from the user-space address
87 The byte read is zero-extended into the results variable.
89 Fetches a word of data (long) from the user-space address
92 Fetches 16 bits of data from the user-space address
94 The half-word read is zero-extended into the results variable.
96 Fetches 32 bits of data from the user-space address
99 Fetches 64 bits of data from the user-space address
102 Fetches a word of data (long) from the user-space address
104 and stores the result in the variable pointed by
107 Fetches 32 bits of data from the user-space address
109 and stores the result in the variable pointed by
112 Fetches 64 bits of data from the user-space address
114 and stores the result in the variable pointed by
123 functions cannot distinguish between -1 read from
124 userspace and function failure.
133 functions return the data fetched or -1 on failure.
139 functions return 0 on success and -1 on failure.