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gists/c-programming/mem/safe_mem.h

66 lines
2.5 KiB
C

/*
* safe_mem.h
*
* A header-only library (macro collection) for safer memory management.
*
* Author: Intel A80486DX2-66
* License: Creative Commons Zero 1.0 Universal
*/
#ifndef _SAFE_MEM_H
#define _SAFE_MEM_H
#include <stdlib.h>
#define SAFE_FREE_ERROR_HOOK /* user-defined */
#define safe_free(ptr) do { \
/* prevents NULL-freeing and double freeing */ \
if (ptr != NULL) { \
free(ptr); \
ptr = NULL; \
} else { SAFE_FREE_ERROR_HOOK; } \
} while (0)
#define precise_malloc(nmemb, size) \
/* prevents incorrect casting */ \
malloc((size_t) nmemb * (size_t) size)
/* secure_erase(dest, count): erases memory explicitly */
#if defined(__FreeBSD__)
# define NO_SECURE_ERASE_WARRANTY 0
# define SECURE_ERASE_WARRANTY "OpenBSD/FreeBSD: explicit_bzero"
# include <strings.h>
# define secure_erase explicit_bzero
#elif defined(_WIN32)
# define NO_SECURE_ERASE_WARRANTY 0
# define SECURE_ERASE_WARRANTY "Microsoft Windows: SecureZeroMemory"
# include <windows.h>
# define secure_erase SecureZeroMemory
#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
# define NO_SECURE_ERASE_WARRANTY 0
# define SECURE_ERASE_WARRANTY "C11+: memset_s"
# define secure_erase(dest, count) memset_s(dest, count, 0, count)
#else
# define NO_SECURE_ERASE_WARRANTY 1
# define __observe__(ptr) do { \
if (*ptr == 0) { \
++(*ptr); \
fprintf(stderr, ""); \
} else \
--(*ptr); \
} while (0)
# define secure_erase(dest, count) do { \
memset(dest, 0, count); \
for (size_t i = 0; i < count; i++) \
__observe__(dest[i]); \
} while (0)
#endif
#endif /* _SAFE_MEM_H */