Re: Forth for Mac OS X Leopard (Intel) - what are the options?

On Apr 11, 11:27 pm, Josh Grams <j...@[EMAIL PROTECTED]
> wrote:

> I've looked at both and I think yours is reasonable...

Thanks very much. Do appreciate that.

So my understanding is correct. My little dance with the assembler to
get a blank .text, the code and predefined dict in the .data and
uninitialized stuff in .bss will actually get linked contiguously - at
least that's how I interpret the hex dump.

> That's BSD for you.  You are required to have .text and .data, so you
> might as well use them.  The other thing you could do (which might save
> a bit of space in the executable is to put everything in .text, have an
> empty .data, and then immediately mprotect() everything to rwx.  But
> your way seems fine to me.

Hmm... I'll have to look this syscall up and try it. This method is
probably more orthodox than my odd way of doing it, isn't it?

OR...

Hmm.. just put assemble the code to the text section instead of data
as you say, link it and _hack_ the binary - ie assuming the load bits
for the text segment are at the same location, for the sake of
illustrating my suggestion, put a 0x07 in byte 0x80 in the header. I
wonder if that would work.

But as you say this is BSD-ish. Will the assembler or linker still
expect a .data section I see it allocated 4k to it. I had actually
expected it to allocate nothing since there was nothing in it - kind
of hoped the linker would see nothing and not link it in. Oh well.

DAMN. I gotta learn to read the headers like you.

> Unfortunately for easy implementation of SAVE-SYSTEM, it looks like the
> linker puts stuff at the end of the file, and I'm not sure if it's
> important.  Is that a stripped binary?  If not, maybe you could e-mail
> me one?  If the stuff at the end isn't important, then you just need to
> zero out a few header fields, set the new size, and write it to a file,
> just like with ELF.

Ok, the executable was not stripped. I actually am not sure what the
linker put at the end yet.

I shall actually strip one and see whether anything remains at the
end.

Thanks for the hex dump. I think I see what you're trying to get at,
it may not be as complicated as I imagined it'd be.

I don't know what command 4, 5, 6, 8 do. I know I can't kill 7. that
much I know.

I'll see what I can come up with after some RTFMing and post some more
results when I get a chance. Really I see what you want to do is get
to the '_pagezero' to do the dirty work. Change permissions for it.
Write what you want. save the binary. I think I am beginning to see
some ways.

Thanks for your patience, I am actually beginning to see what you're
trying to say.

Robert Spykerman