C: add mem/safe_mem.*

c-programming/mem/safe_mem.test.c

@@ -0,0 +1,63 @@
+/*
+ * safe_mem.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] = STDERR_FILENO;
+	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;
+}