\" $NetBSD: kvm_read.3,v 1.9 2016/01/23 00:43:43 dholland Exp $

\" $NetBSD: kvm_read.3,v 1.9 2016/01/23 00:43:43 dholland Exp $
\"
\" Copyright (c) 1992, 1993
\" The Regents of the University of California. All rights reserved.
\"
\" This code is derived from software developed by the Computer Systems
\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract
\" BG 91-66 and contributed to Berkeley.
\"
\" Redistribution and use in source and binary forms, with or without
\" modification, are permitted provided that the following conditions
\" are met:
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\" 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
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\" 3. Neither the name of the University nor the names of its contributors
\" may be used to endorse or promote products derived from this software
\" without specific prior written permission.
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\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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\" @(#)kvm_read.3 8.1 (Berkeley) 6/4/93
\"
Dd June 4, 1993
Dt KVM_READ 3
Os
Sh NAME
Nm kvm_read ,
Nm kvm_write
Nd read or write kernel virtual memory
Sh LIBRARY
Lb libkvm
Sh SYNOPSIS
In kvm.h
Ft ssize_t
Fn kvm_read "kvm_t *kd" "unsigned long addr" "void *buf" "size_t nbytes"
Ft ssize_t
Fn kvm_write "kvm_t *kd" "unsigned long addr" "const void *buf" "size_t nbytes"
Sh DESCRIPTION
The
Fn kvm_read
and
Fn kvm_write
functions are used to read and write kernel virtual memory (or a crash
dump file).
See
Fn kvm_open 3
or
Fn kvm_openfiles 3
for information regarding opening kernel virtual memory and crash dumps.
Pp
The
Fn kvm_read
function transfers
Fa nbytes
bytes of data from
the kernel space address
Fa addr
to
Fa buf .
Conversely,
Fn kvm_write
transfers data from
Fa buf
to
Fa addr .
Unlike their SunOS counterparts, these functions cannot be used to
read or write process address spaces.
Sh RETURN VALUES
Upon success, the number of bytes actually transferred is returned.
Otherwise, -1 is returned.
Sh SEE ALSO
Xr kvm 3 ,
Xr kvm_close 3 ,
Xr kvm_getargv 3 ,
Xr kvm_getenvv 3 ,
Xr kvm_geterr 3 ,
Xr kvm_getprocs 3 ,
Xr kvm_nlist 3 ,
Xr kvm_open 3 ,
Xr kvm_openfiles 3