.\"	$NetBSD: binpatch.8,v 1.8 2009/08/24 12:55:16 tsutsui Exp $
.\"
.\" Copyright (c) 1994 Christian E. Hopps
.\" 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 Christian E. Hopps.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.Dd August 20, 2009
.Dt BINPATCH 8 atari
.Os
.Sh NAME
.Nm binpatch
.Nd "examine and or modify initialized data in an executable binary"
.Sh SYNOPSIS
.Nm binpatch
.Op Fl b | Fl w | Fl l | Fl d
.Op Fl o Ar offset
.Op Fl T Ar saddr
.Fl s Ar symname
.Op Fl r Ar value
.Ar binfile
.Nm binpatch
.Op Fl b | Fl w | Fl l | Fl d
.Op Fl o Ar offset
.Op Fl T Ar saddr
.Fl a Ar addr
.Op Fl r Ar value
.Ar binfile
.Sh DESCRIPTION
.Nm
is used to modify or examine the data associated with a symbol in a binary
file
.Ar binfile .
.Pp
The flags
.Fl b ,
.Fl w ,
.Fl l ,
and
.Fl d
specify the size of the data to be modified or examined.
.Fl b
is for 8bit
.Pq Li int8_t ,
.Fl w
is for 16bit
.Pq Li int16_t ,
.Fl l
is for 32bit
.Pq Li int32_t ,
and
.Fl d
is for 64bit
.Pq Li int64_t
variables.
.Pp
The
.Ar binfile
is scanned in search of the symbol
.Ar symname
(specified with the
.Fl s
flag).
If the symbol is found the current data and address are printed.
.Pp
Next if the
.Fl r
flag has been given, the current data is replaced with that of
.Ar value .
.Pp
If the second form is used the address
.Ar addr
specified with the
.Fl a
flag is used as a direct address into the data section of the binary and
no symbol search is performed.
.Pp
The
.Fl o
flag specifies an offset in
.Li int8_t ,
.Li int16_t ,
.Li int32_t ,
and
.Li int64_t
.Fl ( b ,
.Fl w ,
.Fl l ,
or
.Fl d )
units from the given locator
.Fl ( s
or
.Fl a )
for
.Nm
to perform its described actions.
This might be useful to patch a member of array or structure.
.Pp
The
.Fl T
flag is used to specify the starting address of a.out binary text segment.
Ignored for other binary executable formats.
.Sh SEE ALSO
.Xr gdb 1 ,
.Xr mdsetimage 8
.Sh BUGS
The
.Nm
command doesn't check if size of specified symbol is the same as the
specified size by
.Fl b ,
.Fl w ,
.Fl l ,
or
.Fl d
flag.
.Pp
The
.Nm
command doesn't check if specified address or symbol is a patchable variable
and it might corrupt the specified executable binary.