Problems with LD_PRELOAD and calloc() interposition for certain executables

Question

Relating to a previous question of mine

I\'ve successfully interposed malloc, but calloc seems to be more problematic.

That is with ce

Answer 1

You can get away with a preliminary poor calloc that simply returns NULL. This actually works on Linux, YMMV.

static void* poor_calloc(size_t nmemb, size_t size)
{
    // So dlsym uses calloc internally, which will lead to infinite recursion, since our calloc calls dlsym.
    // Apparently dlsym can cope with slightly wrong calloc, see for further explanation:
    // http://blog.bigpixel.ro/2010/09/interposing-calloc-on-linux
    return NULL; // This is a poor implementation of calloc!
}