gists/c-programming/mem/safe_mem.test.c

/*
 * safe_mem.test.c
 *
 * Author: Intel A80486DX2-66
 * License: Creative Commons Zero 1.0 Universal
 */

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

#include "safe_mem.h"

#undef SAFE_FREE_ERROR_HOOK
#define SAFE_FREE_ERROR_HOOK do {                                             \
    fprintf(stderr, "Double freeing detected!\n");                            \
    exit(EXIT_FAILURE);                                                       \
} while (0)

#define PRINT_POINTER(caption, ptr)                                           \
    printf(caption " = %p\n", (void*) ptr);
#define DUMP_INT_ARRAY(caption, ptr, count) do {                              \
    printf("%s: [", caption);                                                 \
    for (size_t i = 0; i < count; i++) {                                      \
        printf("%d", ptr[i]);                                                 \
        if (i != (count - 1))                                                 \
            printf(", ");                                                     \
    }                                                                         \
    printf("]\n");                                                            \
} while (0)

int main(void) {
#define COUNT 4
	int* integers = precise_malloc(COUNT, sizeof(int));
	PRINT_POINTER("int* integers (before freeing)", integers);

	integers[0] = 0;
	integers[1] = EOF;
	integers[2] = 2;
	integers[3] = 1;
	DUMP_INT_ARRAY("int* integers (before secure erasure)", integers, COUNT);
	printf("Secure erasure is "
#if NO_SECURE_ERASE_WARRANTY
		"not guaranteed!"
#else
		"guaranteed: %s"
#endif
		"\n"
#if !NO_SECURE_ERASE_WARRANTY
		, SECURE_ERASE_WARRANTY
#endif
		);

	secure_erase(integers, COUNT * sizeof(int));
	DUMP_INT_ARRAY("int* integers (after secure erasure)", integers, COUNT);

	safe_free(integers);
	PRINT_POINTER("int* integers (after freeing)", integers);
	fflush(stdout);
	safe_free(integers);
	PRINT_POINTER("int* integers (after two free() calls)", integers);

	return EXIT_SUCCESS;
}