test_allocator.c

#include "test_allocator.h"

#ifdef HAS_EXECINFO
#include <execinfo.h>
#endif

// How many alloc calls we expect
int alloc_calls_expected;
// How many alloc calls we got
int alloc_calls;
// Array of booleans indicating whether to return a block or fail with NULL
call_expectation *expectations;

void set_mock_malloc(int calls, ...) {
  va_list args;
  va_start(args, calls);
  alloc_calls_expected = calls;
  alloc_calls = 0;
  expectations = calloc(calls, sizeof(expectations));
  for (int i = 0; i < calls; i++) {
    // Promotable types, baby
    expectations[i] = va_arg(args, call_expectation);
  }
  va_end(args);
}

void finalize_mock_malloc(void) {
  assert_int_equal(alloc_calls, alloc_calls_expected);
  free(expectations);
}

void print_backtrace(void) {
#if HAS_EXECINFO
  void *buffer[128];
  int frames = backtrace(buffer, 128);
  char **symbols = backtrace_symbols(buffer, frames);
  // Skip this function and the caller
  for (int i = 2; i < frames; ++i) {
    printf("%s\n", symbols[i]);
  }
  free(symbols);
#endif
}

void *instrumented_malloc(size_t size) {
  if (alloc_calls >= alloc_calls_expected) {
    goto error;
  }

  if (expectations[alloc_calls] == MALLOC) {
    alloc_calls++;
    return malloc(size);
  } else if (expectations[alloc_calls] == MALLOC_FAIL) {
    alloc_calls++;
    return NULL;
  }

error:
  print_error(
      "Unexpected call to malloc(%zu) at position %d of %d; expected %d\n",
      size, alloc_calls, alloc_calls_expected,
      alloc_calls < alloc_calls_expected ? expectations[alloc_calls] : -1);
  print_backtrace();
  fail();
  return NULL;
}

void *instrumented_realloc(void *ptr, size_t size) {
  if (alloc_calls >= alloc_calls_expected) {
    goto error;
  }

  if (expectations[alloc_calls] == REALLOC) {
    alloc_calls++;
    return realloc(ptr, size);
  } else if (expectations[alloc_calls] == REALLOC_FAIL) {
    alloc_calls++;
    return NULL;
  }

error:
  print_error(
      "Unexpected call to realloc(%zu) at position %d of %d; expected %d\n",
      size, alloc_calls, alloc_calls_expected,
      alloc_calls < alloc_calls_expected ? expectations[alloc_calls] : -1);
  print_backtrace();
  fail();
  return NULL;
}