104 lines
3.3 KiB
Groff
104 lines
3.3 KiB
Groff
.\" $OpenBSD: kvm_dump.3,v 1.13 2023/01/04 10:59:34 jsg Exp $
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.\" $NetBSD: kvm_dump.3,v 1.1 1996/03/18 21:11:12 leo Exp $
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.\"
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.\" Copyright (c) 1996 Leo Weppelman
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\"
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.Dd $Mdocdate: January 4 2023 $
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.Dt KVM_DUMP_MKHEADER 3
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.Os
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.Sh NAME
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.Nm kvm_dump_mkheader ,
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.Nm kvm_dump_wrtheader ,
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.Nm kvm_dump_inval
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.Nd crash dump support functions
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.Sh SYNOPSIS
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.In kvm.h
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.Ft int
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.Fn kvm_dump_mkheader "kvm_t *kd" "off_t dump_off"
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.Ft int
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.Fn kvm_dump_wrtheader "kvm_t *kd" "FILE *fp" "int dumpsize"
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.Ft int
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.Fn kvm_dump_inval "kvm_t *kd"
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.Sh DESCRIPTION
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First note that the functions described here were designed to be used by
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.Xr savecore 8 .
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.Pp
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The function
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.Fn kvm_dump_mkheader
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checks if the physical memory file associated with
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.Fa kd
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contains a valid crash dump header as generated by a dumping kernel.
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When a valid header is found,
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.Fn kvm_dump_mkheader
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initializes the internal kvm data structures as if a crash dump generated by
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the
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.Xr savecore 8
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program was opened.
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This has the intentional side effect of enabling the
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address translation machinery.
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.Pp
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A call to
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.Fn kvm_dump_mkheader
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will most likely be followed by a call to
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.Fn kvm_dump_wrtheader .
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This function takes care of generating the generic header, the
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.Dv CORE_CPU
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section and the section header of the
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.Dv CORE_DATA
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section.
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The data is written to the file pointed at by
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.Fa fp .
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The
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.Fa dumpsize
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argument is only used to properly set the segment size of the
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.Dv CORE_DATA
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section.
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Note that this function assumes that
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.Fa fp
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is positioned at file location 0.
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This function will not seek and therefore allows
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.Fa fp
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to be a file pointer obtained by
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.Fn zopen .
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.Pp
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The
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.Fn kvm_dump_inval
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function clears the magic number in the physical memory file associated with
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.Fa kd .
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The address translations must be enabled for this to work (thus assuming
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that
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.Fn kvm_dump_mkheader
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was called earlier in the sequence).
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.Sh RETURN VALUES
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All functions return 0 on success, \-1 on failure.
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In the case of failure,
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.Xr kvm_geterr 3
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can be used to retrieve the cause of the error.
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.Sh SEE ALSO
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.Xr kvm 3
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.Sh HISTORY
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These functions first appeared in
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.Nx 1.1a .
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