.\"	$NetBSD: copy.9,v 1.2 1996/01/09 03:23:04 thorpej Exp $
.\"
.\" Copyright (c) 1996 Jason R. Thorpe.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed by Kenneth Stailey.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed for the NetBSD Project
.\"	by Jason R. Thorpe.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: releng/12.2/share/man/man9/copy.9 332654 2018-04-17 17:20:04Z brooks $
.\"
.Dd June 15, 2017
.Dt COPY 9
.Os
.Sh NAME
.Nm copy ,
.Nm copyin ,
.Nm copyin_nofault ,
.Nm copyout ,
.Nm copyout_nofault ,
.Nm copystr ,
.Nm copyinstr
.Nd kernel copy functions
.Sh SYNOPSIS
.In sys/types.h
.In sys/systm.h
.Ft int
.Fn copyin "const void *uaddr" "void *kaddr" "size_t len"
.Ft int
.Fn copyin_nofault "const void *uaddr" "void *kaddr" "size_t len"
.Ft int
.Fn copyout "const void *kaddr" "void *uaddr" "size_t len"
.Ft int
.Fn copyout_nofault "const void *kaddr" "void *uaddr" "size_t len"
.Ft int
.Fn copystr "const void *kfaddr" "void *kdaddr" "size_t len" "size_t *done"
.Ft int
.Fn copyinstr "const void *uaddr" "void *kaddr" "size_t len" "size_t *done"
.Sh DESCRIPTION
The
.Nm
functions are designed to copy contiguous data from one address
to another.
All but
.Fn copystr
copy data from user-space to kernel-space or vice-versa.
.Pp
The
.Fn copyin
and
.Fn copyin_nofault
functions copy
.Fa len
bytes of data from the user-space address
.Fa uaddr
to the kernel-space address
.Fa kaddr .
.Pp
The
.Fn copyout
and
.Fn copyout_nofault
functions copy
.Fa len
bytes of data from the kernel-space address
.Fa kaddr
to the user-space address
.Fa uaddr .
.Pp
The
.Fn copyin_nofault
and
.Fn copyout_nofault
functions require that the kernel-space and user-space data be
accessible without incurring a page fault.
The source and destination addresses must be physically mapped for
read and write access, respectively, and neither the source nor
destination addresses may be pageable.
.Pp
The
.Fn copystr
function copies a NUL-terminated string, at most
.Fa len
bytes long, from kernel-space address
.Fa kfaddr
to kernel-space address
.Fa kdaddr .
The number of bytes actually copied, including the terminating
NUL, is returned in
.Fa *done
(if
.Fa done
is
.No non- Ns Dv NULL ) .
.Pp
The
.Fn copyinstr
function copies a NUL-terminated string, at most
.Fa len
bytes long, from user-space address
.Fa uaddr
to kernel-space address
.Fa kaddr .
The number of bytes actually copied, including the terminating
NUL, is returned in
.Fa *done
(if
.Fa done
is
.No non- Ns Dv NULL ) .
.Sh RETURN VALUES
The
.Nm
functions return 0 on success.
All but
.Fn copystr
return
.Er EFAULT
if a bad address is encountered.
The
.Fn copyin_nofault
and
.Fn copyout_nofault
functions return
.Er EFAULT
if a page fault occurs.
The
.Fn copystr
and
.Fn copyinstr
functions return
.Er ENAMETOOLONG
if the string is longer than
.Fa len
bytes.
.Sh SEE ALSO
.Xr fetch 9 ,
.Xr store 9