Re: compiling libc with --disable-hidden-plt

[GOTO Masanori <gotom@sanori.org>]

At Thu, 23 Feb 2006 10:46:25 +0100,
Andrea Gasparini wrote:
> i'm at first post in this list, and i'm searching for a solution to one 
> problem, so excuse me if it's not pefectly in topic here...
> 
> So, this is the problem:
> i want to wrap almost all system call with LD_PRELOAD, and i would like to 
> write a minimal library (rewrite all libc is quite boring... :-P )
> I would prefer to write only write(), open()  and not having to rewrite 
> functions like fopen(), printf() and so on...
> 
> I found that with --disable-hidden-plt configure option i can build a 
> dynamic library that can be preloaded with my own library: something like
> $LD_PRELOAD="./libtest.so ./libc.nohidden.so" a.out
> 
> 
> but it doesn't work... or better: it works for write(),open() that i 
> directly write into "libtest.so", but printf doesn't call write, so i 
> can't intercept it...

Glibc internally handles system call directly.  It also sometimes uses
wrapper name prefixed with __ .

-- gotom