.\"	$OpenBSD: kvm_dump.3,v 1.1 1996/05/05 14:56:55 deraadt Exp $
.\"	$NetBSD: kvm_dump.3,v 1.1 1996/03/18 21:11:12 leo Exp $
.\"
.\" Copyright (c) 1996 Leo Weppelman
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by Leo Weppelman.
.\" 4. 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.
.\"
.\" 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.
.\"
.\"
.Dd March 17, 1996
.Dt KVM_DUMP 3
.Os
.Sh NAME
.Nm kvm_dump_mkheader ,
.Nm kvm_dump_wrtheader ,
.Nm kvm_dump_inval
.Nd crash-dump support functions
.Sh SYNOPSIS
.Fd #include <kvm.h>
.br
.Ft int
.Fn kvm_dump_mkheader "kvm_t *kd" "off_t dump_off"
.Ft int
.Fn kvm_dump_wrtheader "kvm_t *kd" "FILE *fp" "int dumpsize"
.Ft int
.Fn kvm_dump_inval "kvm_t *kd"
.Sh DESCRIPTION
First note that the functions described here were designed to be used by
.Xr savecore 8 .
.Pp
The function
.Fn kvm_dump_mkheader
checks if the physical memory file associated with 
.Fa kd
contains a valid crash-dump header as generated by a dumping kernel. When a
valid header is found, 
.Fn kvm_dump_mkheader
initializes the internal kvm data structures as if a crash-dump generated by
the
.Xr savecore 8
program was opened. This has the intentional side effect of enabling the
address translation machinery.
.Pp
A call to
.Fn kvm_dump_mkheader
will most likely be followed by a call to
.Fn kvm_dump_wrtheader .
This function takes care of generating the generic header, the CORE_CPU
section and the section header of the CORE_DATA section. The data is written
to the file pointed at by
.Fa fp .
The
.Fa dumpsize
argument is only used to properly the set the segment size of the CORE_DATA
section. Note that this function assumes that
.Fa fp
is positioned at file location 0. This function will not seek and therefore
allows
.Fa fp
to be a file pointer obtained by
.Fn zopen .
.Pp
The
.Fn kvm_dump_inval
function clears the magic number in the physical memory file associated with
.Fa kd .
The address translations must be enabled for this to work (thus assuming
that
.Fn kvm_dum_mkheader
was called earlier in the sequence).
.Sh RETURN VALUES
All functions return 0 on success, -1 on failure. In the case of failure,
.Xr kvm_geterr 3
can be used to retrieve the cause of the error.
.Sh HISTORY
These functions first appeared in NetBSD 1.1A.
.Sh BUGS
There probably are...
.Sh SEE ALSO
.Xr kvm 3