monero/src/common/aligned.c
2019-03-05 22:05:34 +01:00

140 lines
3.9 KiB
C

// Copyright (c) 2017-2019, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include "aligned.h"
static inline int is_power_of_2(size_t n) { return n && (n & (n-1)) == 0; }
#define MAGIC 0xaa0817161500ff81
#define MAGIC_FREED 0xaa0817161500ff82
static void local_abort(const char *msg)
{
fprintf(stderr, "%s\n", msg);
#ifdef NDEBUG
_exit(1);
#else
abort();
#endif
}
typedef struct
{
uint64_t magic;
void *raw;
size_t bytes;
size_t align;
} control;
void *aligned_malloc(size_t bytes, size_t align)
{
void *raw, *ptr;
control *ctrl;
if (!is_power_of_2(align))
return NULL;
if (bytes > (size_t)-1 - align)
return NULL;
if (bytes + align > (size_t)-1 - sizeof(control))
return NULL;
raw = malloc(bytes + sizeof(control) + align);
if (!raw)
return NULL;
ptr = (void*)(((uintptr_t)raw + align + sizeof(control) - 1) & ~(align-1));
ctrl = ((control*)ptr) - 1;
ctrl->magic = MAGIC;
ctrl->raw = raw;
ctrl->bytes = bytes;
ctrl->align = align;
return ptr;
}
void *aligned_realloc(void *ptr, size_t bytes, size_t align)
{
void *raw, *ptr2;
control *ctrl, *ctrl2;
if (!ptr)
return aligned_malloc(bytes, align);
if (!bytes)
{
aligned_free(ptr);
return NULL;
}
if (!is_power_of_2(align))
return NULL;
ctrl = ((control*)ptr) - 1;
if (ctrl->magic == MAGIC_FREED)
local_abort("Double free detected");
if (ctrl->magic != MAGIC)
local_abort("Freeing unallocated memory");
if (ctrl->align != align)
return NULL;
if (ctrl->bytes >= bytes)
return ptr;
if (ctrl->bytes > (size_t)-1 - ctrl->align)
return NULL;
if (ctrl->bytes + ctrl->align > (size_t)-1 - sizeof(control))
return NULL;
raw = malloc(bytes + sizeof(control) + ctrl->align);
if (!raw)
return NULL;
ptr2 = (void*)(((uintptr_t)raw + ctrl->align + sizeof(control) - 1) & ~(ctrl->align-1));
memcpy(ptr2, ptr, ctrl->bytes);
ctrl2 = ((control*)ptr2) - 1;
ctrl2->magic = MAGIC;
ctrl2->raw = raw;
ctrl2->bytes = bytes;
ctrl2->align = ctrl->align;
ctrl->magic = MAGIC_FREED;
free(ctrl->raw);
return ptr2;
}
void aligned_free(void *ptr)
{
if (!ptr)
return;
control *ctrl = ((control*)ptr) - 1;
if (ctrl->magic == MAGIC_FREED)
local_abort("Double free detected");
if (ctrl->magic != MAGIC)
local_abort("Freeing unallocated memory");
ctrl->magic = MAGIC_FREED;
free(ctrl->raw);
}