51ed9ec971
Use misc methods of avoiding unnecesary header includes. Replace int typedefs with int##_t from stdint.h. Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h. Normalize QT_VERSION ifs where possible. Resolve some indirect dependencies as direct ones. Remove extern declarations from .cpp files.
255 lines
8.8 KiB
C++
255 lines
8.8 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
|
|
// Copyright (c) 2009-2013 The Bitcoin developers
|
|
// Distributed under the MIT/X11 software license, see the accompanying
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
#ifndef BITCOIN_ALLOCATORS_H
|
|
#define BITCOIN_ALLOCATORS_H
|
|
|
|
#include <map>
|
|
#include <string>
|
|
#include <string.h>
|
|
|
|
#include <boost/thread/mutex.hpp>
|
|
#include <boost/thread/once.hpp>
|
|
#include <openssl/crypto.h> // for OPENSSL_cleanse()
|
|
|
|
/**
|
|
* Thread-safe class to keep track of locked (ie, non-swappable) memory pages.
|
|
*
|
|
* Memory locks do not stack, that is, pages which have been locked several times by calls to mlock()
|
|
* will be unlocked by a single call to munlock(). This can result in keying material ending up in swap when
|
|
* those functions are used naively. This class simulates stacking memory locks by keeping a counter per page.
|
|
*
|
|
* @note By using a map from each page base address to lock count, this class is optimized for
|
|
* small objects that span up to a few pages, mostly smaller than a page. To support large allocations,
|
|
* something like an interval tree would be the preferred data structure.
|
|
*/
|
|
template <class Locker> class LockedPageManagerBase
|
|
{
|
|
public:
|
|
LockedPageManagerBase(size_t page_size):
|
|
page_size(page_size)
|
|
{
|
|
// Determine bitmask for extracting page from address
|
|
assert(!(page_size & (page_size-1))); // size must be power of two
|
|
page_mask = ~(page_size - 1);
|
|
}
|
|
|
|
~LockedPageManagerBase()
|
|
{
|
|
assert(this->GetLockedPageCount() == 0);
|
|
}
|
|
|
|
|
|
// For all pages in affected range, increase lock count
|
|
void LockRange(void *p, size_t size)
|
|
{
|
|
boost::mutex::scoped_lock lock(mutex);
|
|
if(!size) return;
|
|
const size_t base_addr = reinterpret_cast<size_t>(p);
|
|
const size_t start_page = base_addr & page_mask;
|
|
const size_t end_page = (base_addr + size - 1) & page_mask;
|
|
for(size_t page = start_page; page <= end_page; page += page_size)
|
|
{
|
|
Histogram::iterator it = histogram.find(page);
|
|
if(it == histogram.end()) // Newly locked page
|
|
{
|
|
locker.Lock(reinterpret_cast<void*>(page), page_size);
|
|
histogram.insert(std::make_pair(page, 1));
|
|
}
|
|
else // Page was already locked; increase counter
|
|
{
|
|
it->second += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
// For all pages in affected range, decrease lock count
|
|
void UnlockRange(void *p, size_t size)
|
|
{
|
|
boost::mutex::scoped_lock lock(mutex);
|
|
if(!size) return;
|
|
const size_t base_addr = reinterpret_cast<size_t>(p);
|
|
const size_t start_page = base_addr & page_mask;
|
|
const size_t end_page = (base_addr + size - 1) & page_mask;
|
|
for(size_t page = start_page; page <= end_page; page += page_size)
|
|
{
|
|
Histogram::iterator it = histogram.find(page);
|
|
assert(it != histogram.end()); // Cannot unlock an area that was not locked
|
|
// Decrease counter for page, when it is zero, the page will be unlocked
|
|
it->second -= 1;
|
|
if(it->second == 0) // Nothing on the page anymore that keeps it locked
|
|
{
|
|
// Unlock page and remove the count from histogram
|
|
locker.Unlock(reinterpret_cast<void*>(page), page_size);
|
|
histogram.erase(it);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Get number of locked pages for diagnostics
|
|
int GetLockedPageCount()
|
|
{
|
|
boost::mutex::scoped_lock lock(mutex);
|
|
return histogram.size();
|
|
}
|
|
|
|
private:
|
|
Locker locker;
|
|
boost::mutex mutex;
|
|
size_t page_size, page_mask;
|
|
// map of page base address to lock count
|
|
typedef std::map<size_t,int> Histogram;
|
|
Histogram histogram;
|
|
};
|
|
|
|
|
|
/**
|
|
* OS-dependent memory page locking/unlocking.
|
|
* Defined as policy class to make stubbing for test possible.
|
|
*/
|
|
class MemoryPageLocker
|
|
{
|
|
public:
|
|
/** Lock memory pages.
|
|
* addr and len must be a multiple of the system page size
|
|
*/
|
|
bool Lock(const void *addr, size_t len);
|
|
/** Unlock memory pages.
|
|
* addr and len must be a multiple of the system page size
|
|
*/
|
|
bool Unlock(const void *addr, size_t len);
|
|
};
|
|
|
|
/**
|
|
* Singleton class to keep track of locked (ie, non-swappable) memory pages, for use in
|
|
* std::allocator templates.
|
|
*
|
|
* Some implementations of the STL allocate memory in some constructors (i.e., see
|
|
* MSVC's vector<T> implementation where it allocates 1 byte of memory in the allocator.)
|
|
* Due to the unpredictable order of static initializers, we have to make sure the
|
|
* LockedPageManager instance exists before any other STL-based objects that use
|
|
* secure_allocator are created. So instead of having LockedPageManager also be
|
|
* static-intialized, it is created on demand.
|
|
*/
|
|
class LockedPageManager: public LockedPageManagerBase<MemoryPageLocker>
|
|
{
|
|
public:
|
|
static LockedPageManager& Instance()
|
|
{
|
|
boost::call_once(LockedPageManager::CreateInstance, LockedPageManager::init_flag);
|
|
return *LockedPageManager::_instance;
|
|
}
|
|
|
|
private:
|
|
LockedPageManager();
|
|
|
|
static void CreateInstance()
|
|
{
|
|
// Using a local static instance guarantees that the object is initialized
|
|
// when it's first needed and also deinitialized after all objects that use
|
|
// it are done with it. I can think of one unlikely scenario where we may
|
|
// have a static deinitialization order/problem, but the check in
|
|
// LockedPageManagerBase's destructor helps us detect if that ever happens.
|
|
static LockedPageManager instance;
|
|
LockedPageManager::_instance = &instance;
|
|
}
|
|
|
|
static LockedPageManager* _instance;
|
|
static boost::once_flag init_flag;
|
|
};
|
|
|
|
//
|
|
// Functions for directly locking/unlocking memory objects.
|
|
// Intended for non-dynamically allocated structures.
|
|
//
|
|
template<typename T> void LockObject(const T &t) {
|
|
LockedPageManager::Instance().LockRange((void*)(&t), sizeof(T));
|
|
}
|
|
|
|
template<typename T> void UnlockObject(const T &t) {
|
|
OPENSSL_cleanse((void*)(&t), sizeof(T));
|
|
LockedPageManager::Instance().UnlockRange((void*)(&t), sizeof(T));
|
|
}
|
|
|
|
//
|
|
// Allocator that locks its contents from being paged
|
|
// out of memory and clears its contents before deletion.
|
|
//
|
|
template<typename T>
|
|
struct secure_allocator : public std::allocator<T>
|
|
{
|
|
// MSVC8 default copy constructor is broken
|
|
typedef std::allocator<T> base;
|
|
typedef typename base::size_type size_type;
|
|
typedef typename base::difference_type difference_type;
|
|
typedef typename base::pointer pointer;
|
|
typedef typename base::const_pointer const_pointer;
|
|
typedef typename base::reference reference;
|
|
typedef typename base::const_reference const_reference;
|
|
typedef typename base::value_type value_type;
|
|
secure_allocator() throw() {}
|
|
secure_allocator(const secure_allocator& a) throw() : base(a) {}
|
|
template <typename U>
|
|
secure_allocator(const secure_allocator<U>& a) throw() : base(a) {}
|
|
~secure_allocator() throw() {}
|
|
template<typename _Other> struct rebind
|
|
{ typedef secure_allocator<_Other> other; };
|
|
|
|
T* allocate(std::size_t n, const void *hint = 0)
|
|
{
|
|
T *p;
|
|
p = std::allocator<T>::allocate(n, hint);
|
|
if (p != NULL)
|
|
LockedPageManager::Instance().LockRange(p, sizeof(T) * n);
|
|
return p;
|
|
}
|
|
|
|
void deallocate(T* p, std::size_t n)
|
|
{
|
|
if (p != NULL)
|
|
{
|
|
OPENSSL_cleanse(p, sizeof(T) * n);
|
|
LockedPageManager::Instance().UnlockRange(p, sizeof(T) * n);
|
|
}
|
|
std::allocator<T>::deallocate(p, n);
|
|
}
|
|
};
|
|
|
|
|
|
//
|
|
// Allocator that clears its contents before deletion.
|
|
//
|
|
template<typename T>
|
|
struct zero_after_free_allocator : public std::allocator<T>
|
|
{
|
|
// MSVC8 default copy constructor is broken
|
|
typedef std::allocator<T> base;
|
|
typedef typename base::size_type size_type;
|
|
typedef typename base::difference_type difference_type;
|
|
typedef typename base::pointer pointer;
|
|
typedef typename base::const_pointer const_pointer;
|
|
typedef typename base::reference reference;
|
|
typedef typename base::const_reference const_reference;
|
|
typedef typename base::value_type value_type;
|
|
zero_after_free_allocator() throw() {}
|
|
zero_after_free_allocator(const zero_after_free_allocator& a) throw() : base(a) {}
|
|
template <typename U>
|
|
zero_after_free_allocator(const zero_after_free_allocator<U>& a) throw() : base(a) {}
|
|
~zero_after_free_allocator() throw() {}
|
|
template<typename _Other> struct rebind
|
|
{ typedef zero_after_free_allocator<_Other> other; };
|
|
|
|
void deallocate(T* p, std::size_t n)
|
|
{
|
|
if (p != NULL)
|
|
OPENSSL_cleanse(p, sizeof(T) * n);
|
|
std::allocator<T>::deallocate(p, n);
|
|
}
|
|
};
|
|
|
|
// This is exactly like std::string, but with a custom allocator.
|
|
typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
|
|
|
|
#endif
|