testA.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>

#include "elf_hook.h"

#define LIBFUNC_PATH "./libfunc.so" //position dependent code

char* wrapfunc(char* A, char* B, uint32_t length);
char* hook(char* A, char* B, uint32_t length);

void set_hook(void * handle) {
  void *base = NULL;
  if (NULL == handle) {
    fprintf(stderr, "Failed to open \"%s\"! %s\n", LIBFUNC_PATH, dlerror()); exit(1);
  }
  if(get_module_base_address(LIBFUNC_PATH, handle, &base)) {
    fprintf(stderr, "Failed to get module base addresses\n");
    exit(1);
  }
  printf("base: %p\n", base);
  void *orig = elf_hook(LIBFUNC_PATH, base, "func", hook);
  if (NULL == orig) {
    fprintf(stderr, "Redirection failed!\n");
    exit(1);
  }
}

int main() {
  uint32_t length = 3;
  char *A = malloc(length*sizeof(int32_t));
  char *B = malloc(length*sizeof(int32_t));

  int i;
  for ( i=0; i<length; i++ ) {
    ((int32_t*)A)[i]= rand() % 100;
    ((int32_t*)B)[i] = rand() % 100;
  }

  wrapfunc(A, B, length);

  void *handle = dlopen(LIBFUNC_PATH, RTLD_LAZY);
  printf("----\n");
  set_hook(handle);
  printf("----\n");

  wrapfunc(A, B, length);

  dlclose(handle);

  return 0;
}