Re: dlopening the C runtime library

[Sam Varshavchik]

Howard Chu writes:

> > Running something in the configure script would work for me. Has anyone ever
> > did something like this? Such as, determining that lt_dlopenext() ends up
> > really opening "libc.so.6", so that's what I really need to open?
>
> None of this guesswork should be needed. Since the main program already 
> depends on libc, you should be able to lt_dlopen(NULL) and reference the main 
> program to find libc's symbols.

My use case is intercepting a main application's calls to library 
functions. I set LD_PRELOAD to preload my own shared library which provides 
replacement symbols for socket(), connect(), etc…

My wrapper needs to find the real socket() and connect(). I haven't checked 
this yet, but I suspect that since my shared library was loaded ahead of 
libc, after lt_dlopen(NULL), using lt_dlsym() will simply return a pointer 
to my own symbols, rather than libc's.

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