Re: read/write arbitrary files

[Michael Snyder <msnyder@vmware.com>]

Bjorn Helgaas wrote:
> On Monday 25 August 2008 11:23:10 am Michael Snyder wrote:
>> Bjorn Helgaas wrote:
>>> I'd like to use gdb to examine and update arbitrary files.  In
>>> particular, I'd like to disassemble and patch files like /dev/mem
>>> that are not in executable or core formats.
>>>
>>> Is there already a way to do this?  If not, could there be?  This
>>> was a very useful feature of adb.
>> It's not really what gdb is good for.
>> Arbitrary files such as /dev/mem have no symbols and no types.
>> It should be easy to either use an existing hex editor, or
>> write one to do this sort of patching.  This tool could be
>> orders of magnitude less complicated than gdb.
> 
> The hex editor part is easy.  I know how to do that already.
> 
> The disassembly part is much harder, and this is the part
> I'm looking for.  It'd be very handy to use all the
> disassemblers and the well-known user interface of gdb.
> 
> Another useful feature of gdb is its knowledge of types.  It
> would be convenient to be able to read type information from
> an executable, then use that information to format structures
> from /dev/mem.

I see.

Well, if it were me, I think I would write a little
proxy program that could read /dev/mem, and then serve
memory packets to gdb using a socket and the gdb remote
protocol, after the fashion of gdbserver.