#include <stdlib.h>
#include <dlfcn.h>
#include <errno.h>

void *malloc(size_t size) {
    // before call to malloc
    void *(*_malloc)(size_t);
    if ((_malloc = dlsym(RTLD_NEXT, "malloc")) == NULL) {
        errno = ENOSYS;
        return NULL;
    }
    void *ret = _malloc(size);
    // after call to malloc
    return ret;
}