Re: A copy/save command ...

[Michael Snyder <msnyder at redhat dot com>]

Andrew Cagney wrote:
> 
> Hello,
> 
> To toss out an idea.  One of those oft mentioned missing features is a
> command to read/write binary data to/from GDB's target memory.  There is
> the load command, but that works on object files (readable via BFD).
> 
> Anyway, I've two vague thoughts on the syntax/semantics:
> 
> 1. (gdb) copy <expression> <file>
> 
> The result of <expression> is written to the raw file.  This expoits the
> fact that GDB stores an expression in target form in host memory.
> Consequently, the copy command just writes that raw data to the file.
> 
> 2. (gdb) copy <address> <length> <file>
> or (gdb) copy/<length> <address> <file>
> 
> or similar.  A more traditional <address>/<length> approach.
> ``copy/<length>'' comes from ``x/<length>''.
> 
> better suggestions welcome.

How about (gdb) unload <filename> <?offsets?>
Not sure what options you might want, but load has offsets, so
unload might want them as well.   Maybe an option to specify 
file format (srec?)

I once wrote a "reload" command that was an optimized version of "load":
it would iterate thru the object file sections, ignore the read-only
ones, 
and for each writeable section it would do a CRC and compare what was 
in target memory.  Only if they differed, it would download that
section.

You might do something similar (assuming you had an object file):
iterate thru the sections, take the memory ranges for the writeable
ones, and copy those ranges to your output file (perhaps in a 
format such as srec which GDB already knows how to reload later).