Re: LD_PRELOAD

[Geoff Keating <geoffk@ozemail.com.au>]

> Mailing-List: contact libc-alpha-help@sourceware.cygnus.com; run by ezmlm
> From: "Karl-Andre' Skevik" <karls@kosmo.inet.no>
> Date: 20 May 1999 15:37:54 +0200
> 
> Hello,
> 	are there any significant differences between the
> dlopen/LD_PRELOAD interface in glibc2.1 and other implementations?
> There have been several reports that both NEC socks and dante (which
> both use the interface to wrap several i/o functions) doesn't work
> with glibc2.1.

The dlopen and LD_PRELOAD interface have not changed, but glibc 2.1
has.  

I believe your problems are caused by the introduction of symbol
versioning and the related changes.

Such techniques (overriding routines in the libc) have always been
implementation-dependent.  You will probably need to do various
special things to make it work with glibc 2.1, if this is possible at
all.

Without more information on what problems you are experiencing and
what functions you are trying to override, I can't be more specific.

Have you considered implementing your functionality in the kernel
instead?  Or building a custom version of libc with the changes you
want to make included?

-- 
Geoffrey Keating <geoffk@ozemail.com.au>