encfs/cipher/MemoryPool.cpp
2016-09-10 12:51:20 +02:00

131 lines
3.2 KiB
C++

/*****************************************************************************
* Author: Valient Gough <vgough@pobox.com>
*
*****************************************************************************
* Copyright (c) 2003, Valient Gough
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "MemoryPool.h"
#include <cstring>
#include <openssl/ossl_typ.h>
#include <pthread.h>
#ifdef HAVE_VALGRIND_MEMCHECK_H
#include <valgrind/memcheck.h>
#else
#define VALGRIND_MAKE_MEM_NOACCESS(a, b)
#define VALGRIND_MAKE_MEM_UNDEFINED(a, b)
#endif
#include <openssl/buffer.h>
#define BLOCKDATA(BLOCK) (unsigned char *)BLOCK->data->data
namespace encfs {
struct BlockList {
BlockList *next;
int size;
BUF_MEM *data;
};
static BlockList *allocBlock(int size) {
BlockList *block = new BlockList;
block->size = size;
block->data = BUF_MEM_new();
BUF_MEM_grow(block->data, size);
VALGRIND_MAKE_MEM_NOACCESS(block->data->data, block->data->max);
return block;
}
static void freeBlock(BlockList *el) {
VALGRIND_MAKE_MEM_UNDEFINED(el->data->data, el->data->max);
BUF_MEM_free(el->data);
delete el;
}
static pthread_mutex_t gMPoolMutex = PTHREAD_MUTEX_INITIALIZER;
static BlockList *gMemPool = NULL;
MemBlock MemoryPool::allocate(int size) {
pthread_mutex_lock(&gMPoolMutex);
BlockList *parent = NULL;
BlockList *block = gMemPool;
// check if we already have a large enough block available..
while (block != NULL && block->size < size) {
parent = block;
block = block->next;
}
// unlink block from list
if (block) {
if (!parent)
gMemPool = block->next;
else
parent->next = block->next;
}
pthread_mutex_unlock(&gMPoolMutex);
if (!block) block = allocBlock(size);
block->next = NULL;
MemBlock result;
result.data = BLOCKDATA(block);
result.internalData = block;
VALGRIND_MAKE_MEM_UNDEFINED(result.data, size);
return result;
}
void MemoryPool::release(const MemBlock &mb) {
pthread_mutex_lock(&gMPoolMutex);
BlockList *block = (BlockList *)mb.internalData;
// just to be sure there's nothing important left in buffers..
VALGRIND_MAKE_MEM_UNDEFINED(block->data->data, block->size);
memset(BLOCKDATA(block), 0, block->size);
VALGRIND_MAKE_MEM_NOACCESS(block->data->data, block->data->max);
block->next = gMemPool;
gMemPool = block;
pthread_mutex_unlock(&gMPoolMutex);
}
void MemoryPool::destroyAll() {
pthread_mutex_lock(&gMPoolMutex);
BlockList *block = gMemPool;
gMemPool = NULL;
pthread_mutex_unlock(&gMPoolMutex);
while (block != NULL) {
BlockList *next = block->next;
freeBlock(block);
block = next;
}
}
} // namespace encfs