How to prevent a specific dynamic library from being loaded

There is a utility called patchelf that should allow you to remove DSO dependencies from executables.

Here's an example to remove dependencies libpthreadfrom a dummy executable :

echo 'int main(){}' | 
    gcc -x c - -Wl,--no-as-needed -lpthread && 
    ldd a.out &&
    patchelf --remove-needed libpthread.so.0 a.out && 
    echo ====== && 
    ldd a.out

my output:

    linux-vdso.so.1 =>  (0x00007ffeced67000)
    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f21560f1000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2155d28000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f215630f000)
======
    linux-vdso.so.1 =>  (0x00007fffac536000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f6235c0d000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f6235fd6000)

renew:

If using libtxc_dxtn.soload dlopen, you can preload( LD_PRELOAD) a tiny library that provides an dlopenoverride that will return NULLif its filename argument is "libtxc_dxtn.so"( ltraceshould help you find the actual filename argument you need to guard against). It's just like:

#define _GNU_SOURCE
#include <dlfcn.h>
#include <string.h>

void *dlopen(char const *Fnm, int Flg)
{
    void *(*real_dlopen)(char const *,  int);
    *(void**)(&real_dlopen) = dlsym(RTLD_NEXT, "dlopen");
    if(0==strcmp("libtxc_dxtn.so", Fnm)){
        return NULL;
    }else{
        return real_dlopen(Fnm, Flg);   
    }

}