From owner-freebsd-hackers  Mon Jun 28 21:45:31 1999
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To: Amol Mohite <amol2@m-net.arbornet.org>
Cc: freebsd-hackers@FreeBSD.ORG
Subject: Re: environment strings 
In-reply-to: Your message of "Mon, 28 Jun 1999 23:32:59 -0400."
             <Pine.BSI.3.96.990628233126.24384A-100000@m-net.arbornet.org> 
Date: Tue, 29 Jun 1999 14:44:39 +1000
From: Patryk Zadarnowski <patrykz@mycenae.ilion.eu.org>
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> I know about envp.
> 
> What I want to know is the exact position of these variables on the stack.
> 
> and if anywhere I can find some data, on the exact compisoition of the
> stcak, then it will be very helpful.
> 
> references of books and websites wil be most helpful.

Basically, i386 BSD kernels (you're after i386, aren't you?) point ESP to
the following "struct" (which means that it will be dumped at the very
top of the address space)

 	struct kframe {
	    int   argc;		/* "argc" to be passed to main() */
	    char *argv[argc];	/* "argv" to be passed to main() */
	    char *null;		/* a NULL pointer terminating argv[] */
	    char **envp;	/* value to be assigned to "environ" */
	};
 
/usr/src/lib/csu/i386/crt0.c is probably the best reference you can get
your hands on ;)

Patryk.


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