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Date: Thu, 18 Nov 2004 11:28:41 +0100 (MET)
From: Jan Engelhardt <jengelh@linux01.gwdg.de>
To: Valdis.Kletnieks@vt.edu
cc: A M <alim1993@yahoo.com>, linux-kernel@vger.kernel.org
Subject: Re: Accessing program counter registers from within C or Aseembler.
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>> Does anybody know how to access the address of the
>> current executing instruction in C while the program
>> is executing?
>
>In other words, are you trying to answer "Where in memory am *I*?"
>or "Where in memory is <that very recent code I want to look at>?"
>
>(Hint - for the former, you can probably get very good approximations
>by just looking at the entry point address for the function:
>
>	(void *) where = &__FUNCTION__;

Well, that's only the function in which you are (i.e. it's an approximation to
EIP)

>> Also, is there a method to load a program image from
>> memory not a file (an exec that works with a memory
>> address)? Mainly I am looking for a method that brings
>> a program image into memory modify parts of it and
>> start the in-memory modified version.
>
>In user space, you probably want either mmap() or dlopen(), depending what it
>is you're trying to do, most likely...

Those pages will probably have NX set then, for archs which support it.




Jan Engelhardt
-- 
Gesellschaft für Wissenschaftliche Datenverarbeitung
Am Fassberg, 37077 Göttingen, www.gwdg.de
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