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/*
* Copyright (C) 2008-2014 Tobias Brunner
* Copyright (C) 2008 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup memory_i memory
* @{ @ingroup utils_i
*/
#ifndef MEMORY_H_
#define MEMORY_H_
/**
* Helper function that compares two binary blobs for equality
*/
static inline bool memeq(const void *x, const void *y, size_t len)
{
return memcmp(x, y, len) == 0;
}
/**
* Same as memeq(), but with a constant runtime, safe for cryptographic use.
*/
bool memeq_const(const void *x, const void *y, size_t len);
/**
* Calling memcpy() with NULL pointers, even with n == 0, results in undefined
* behavior according to the C standard. This version is guaranteed to not
* access the pointers if n is 0.
*/
static inline void *memcpy_noop(void *dst, const void *src, size_t n)
{
return n ? memcpy(dst, src, n) : dst;
}
#ifdef memcpy
# undef memcpy
#endif
#define memcpy(d,s,n) memcpy_noop(d,s,n)
/**
* Calling memmove() with NULL pointers, even with n == 0, results in undefined
* behavior according to the C standard. This version is guaranteed to not
* access the pointers if n is 0.
*/
static inline void *memmove_noop(void *dst, const void *src, size_t n)
{
return n ? memmove(dst, src, n) : dst;
}
#ifdef memmove
# undef memmove
#endif
#define memmove(d,s,n) memmove_noop(d,s,n)
/**
* Calling memset() with a NULL pointer, even with n == 0, results in undefined
* behavior according to the C standard. This version is guaranteed to not
* access the pointer if n is 0.
*/
static inline void *memset_noop(void *s, int c, size_t n)
{
return n ? memset(s, c, n) : s;
}
#ifdef memset
# undef memset
#endif
#define memset(s,c,n) memset_noop(s,c,n)
/**
* Same as memcpy, but XORs src into dst instead of copy
*/
void memxor(u_int8_t dest[], u_int8_t src[], size_t n);
/**
* Safely overwrite n bytes of memory at ptr with zero, non-inlining variant.
*/
void memwipe_noinline(void *ptr, size_t n);
/**
* Safely overwrite n bytes of memory at ptr with zero, inlining variant.
*/
static inline void memwipe_inline(void *ptr, size_t n)
{
volatile char *c = (volatile char*)ptr;
size_t m, i;
/* byte wise until long aligned */
for (i = 0; (uintptr_t)&c[i] % sizeof(long) && i < n; i++)
{
c[i] = 0;
}
/* word wise */
if (n >= sizeof(long))
{
for (m = n - sizeof(long); i <= m; i += sizeof(long))
{
*(volatile long*)&c[i] = 0;
}
}
/* byte wise of the rest */
for (; i < n; i++)
{
c[i] = 0;
}
}
/**
* Safely overwrite n bytes of memory at ptr with zero, auto-inlining variant.
*/
static inline void memwipe(void *ptr, size_t n)
{
if (!ptr)
{
return;
}
if (__builtin_constant_p(n))
{
memwipe_inline(ptr, n);
}
else
{
memwipe_noinline(ptr, n);
}
}
/**
* A variant of strstr with the characteristics of memchr, where haystack is not
* a null-terminated string but simply a memory area of length n.
*/
void *memstr(const void *haystack, const char *needle, size_t n);
/**
* Replacement for memrchr(3) if it is not provided by the C library.
*
* @param s start of the memory area to search
* @param c character to search
* @param n length of memory area to search
* @return pointer to the found character or NULL
*/
void *utils_memrchr(const void *s, int c, size_t n);
#ifndef HAVE_MEMRCHR
#define memrchr(s,c,n) utils_memrchr(s,c,n)
#endif
#ifndef HAVE_FMEMOPEN
# ifdef HAVE_FUNOPEN
# define HAVE_FMEMOPEN
# define HAVE_FMEMOPEN_FALLBACK
# include <stdio.h>
/**
* fmemopen(3) fallback using BSD funopen.
*
* We could also provide one using fopencookie(), but should we have it we
* most likely have fmemopen().
*
* fseek() is currently not supported.
*/
FILE *fmemopen(void *buf, size_t size, const char *mode);
# endif /* FUNOPEN */
#endif /* FMEMOPEN */
/**
* printf hook for memory areas.
*
* Arguments are:
* u_char *ptr, u_int len
*/
int mem_printf_hook(printf_hook_data_t *data, printf_hook_spec_t *spec,
const void *const *args);
#endif /** MEMORY_H_ @} */
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