mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
123 lines
3.2 KiB
Groff
123 lines
3.2 KiB
Groff
.\"
|
|
.\" Copyright (c) 2004-2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 16, 2004
|
|
.Dt G_DATA 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm g_read_data ,
|
|
.Nm g_write_data
|
|
.Nd "read/write data from/to GEOM consumer"
|
|
.Sh SYNOPSIS
|
|
.In geom/geom.h
|
|
.Ft "void *"
|
|
.Fo g_read_data
|
|
.Fa "struct g_consumer *cp" "off_t offset" "off_t length" "int *error"
|
|
.Fc
|
|
.Ft int
|
|
.Fo g_write_data
|
|
.Fa "struct g_consumer *cp" "off_t offset" "void *ptr" "off_t length"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn g_read_data
|
|
function reads
|
|
.Fa length
|
|
bytes of data from the provider attached to consumer
|
|
.Fa cp ,
|
|
starting at offset
|
|
.Fa offset .
|
|
The buffer returned from
|
|
.Fn g_read_data
|
|
is allocated with
|
|
.Fn g_malloc ,
|
|
so it should be freed by the caller with
|
|
.Fn g_free
|
|
after use.
|
|
If the operation fails, an error value will be stored in the
|
|
.Fa error
|
|
argument if it is not
|
|
.Dv NULL .
|
|
.Pp
|
|
The
|
|
.Fn g_write_data
|
|
function writes
|
|
.Fa length
|
|
bytes of data from the buffer pointed to by
|
|
.Fa ptr
|
|
to the provider attached to consumer
|
|
.Fa cp ,
|
|
starting at offset
|
|
.Fa offset .
|
|
.Sh RESTRICTIONS/CONDITIONS
|
|
The
|
|
.Fa length
|
|
argument
|
|
should be a multiple of the provider's sectorsize
|
|
and less than or equal to
|
|
.Dv DFLTPHYS
|
|
.Dv ( DFLTPHYS
|
|
is defined in
|
|
.In sys/param.h ) .
|
|
.Pp
|
|
The topology lock must not be held.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn g_read_data
|
|
function returns a pointer to a data buffer or
|
|
.Dv NULL
|
|
if an error occurred.
|
|
In that case an error value is stored in the
|
|
.Fa error
|
|
argument unless it is
|
|
.Dv NULL .
|
|
.Pp
|
|
The
|
|
.Fn g_write_data
|
|
function returns 0 if successful; otherwise an error code is returned.
|
|
.Sh ERRORS
|
|
Possible errors:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to the consumer.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr geom 4 ,
|
|
.Xr DECLARE_GEOM_CLASS 9 ,
|
|
.Xr g_access 9 ,
|
|
.Xr g_attach 9 ,
|
|
.Xr g_bio 9 ,
|
|
.Xr g_consumer 9 ,
|
|
.Xr g_event 9 ,
|
|
.Xr g_geom 9 ,
|
|
.Xr g_provider 9 ,
|
|
.Xr g_provider_by_name 9 ,
|
|
.Xr g_wither_geom 9
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
This manual page was written by
|
|
.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .
|