Date: Sat, 28 Feb 1998 12:07:43 -0800 (PST)
Message-Id: <199802282007.MAA15184@adit.ap.net>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
To: "Pieter van Ginkel" <pginkel AT westbrabant DOT net>, djgpp AT delorie DOT com
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: Using COFF files.
Precedence: bulk

At 10:10  2/27/1998 GMT, Pieter van Ginkel wrote:
>I want to create a library that dynamically loads routines from COFF files
>into memory and then returns the pointer to the routines in the COFF file to
>the program. I've been reading the COFF things from the Delorie DJGPP site
>and there are a few things I don't really understand. Can anybody help me?
>
>* First, How can I just load the whole COFF file into memory and let the
>whole thing run. Is that at all possible or is there more to be done before
>the file runs.

The best answer to this is probably to look at how DJGPP does it. Get the
`djlsr201.zip' package and see `src/stub/stub.asm'.

>* I suppose that the entries in the header files are converted to external
>symbols. Do I have to do something's with these?
>* Suppose I open the COFF file, locate a function, load that one into memory
>and that return the pointer to the begin of that function to the user. I
>don't think that's the right thing to do? If I use functions from the libc
>library, how do I ensure that the routine has access to these? Do I need to
>collect all the pointers to these routines that are already into memory (the
>loading program) and give them to the function? How do I do this.
>
>Could somebody give me some guidelines so I can get starting at my loader???

Be aware that you are re-inventing the wheel here. Several dynamic loaders
exist for DJGPP. Look in the `v2tk' directory of Simtelnet.

Even if you do want to write your own, these packages will probably help you
figure out what to do.

Nate Eldredge
eldredge AT ap DOT net