Atmosphere/libraries/libstratosphere/source/fssystem/fssystem_key_slot_cache.hpp

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/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <stratosphere.hpp>
namespace ams::fssystem {
class KeySlotCacheAccessor : public ::ams::fs::impl::Newable {
NON_COPYABLE(KeySlotCacheAccessor);
NON_MOVEABLE(KeySlotCacheAccessor);
private:
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util::unique_lock<os::SdkMutex> m_lk;
const s32 m_slot_index;
public:
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KeySlotCacheAccessor(s32 idx, util::unique_lock<os::SdkMutex> &&l) : m_lk(std::move(l)), m_slot_index(idx) { /* ... */ }
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s32 GetKeySlotIndex() const { return m_slot_index; }
};
class KeySlotCacheEntry : public util::IntrusiveListBaseNode<KeySlotCacheEntry> {
NON_COPYABLE(KeySlotCacheEntry);
NON_MOVEABLE(KeySlotCacheEntry);
public:
static constexpr size_t KeySize = crypto::AesDecryptor128::KeySize;
private:
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const s32 m_slot_index;
u8 m_key1[KeySize];
s32 m_key2;
public:
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explicit KeySlotCacheEntry(s32 idx) : m_slot_index(idx), m_key2(-1) {
std::memset(m_key1, 0, sizeof(m_key1));
}
bool Contains(const void *key, size_t key_size, s32 key2) const {
AMS_ASSERT(key_size == KeySize);
AMS_UNUSED(key_size);
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return key2 == m_key2 && std::memcmp(m_key1, key, KeySize) == 0;
}
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s32 GetKeySlotIndex() const { return m_slot_index; }
void SetKey(const void *key, size_t key_size, s32 key2) {
AMS_ASSERT(key_size == KeySize);
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std::memcpy(m_key1, key, key_size);
m_key2 = key2;
}
};
class KeySlotCache {
NON_COPYABLE(KeySlotCache);
NON_MOVEABLE(KeySlotCache);
private:
using KeySlotCacheEntryList = util::IntrusiveListBaseTraits<KeySlotCacheEntry>::ListType;
private:
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os::SdkMutex m_mutex;
KeySlotCacheEntryList m_high_priority_mru_list;
KeySlotCacheEntryList m_low_priority_mru_list;
public:
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constexpr KeySlotCache() : m_mutex(), m_high_priority_mru_list(), m_low_priority_mru_list() { /* ... */ }
Result AllocateHighPriority(std::unique_ptr<KeySlotCacheAccessor> *out, const void *key, size_t key_size, s32 key2) {
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return this->AllocateFromLru(out, m_high_priority_mru_list, key, key_size, key2);
}
Result AllocateLowPriority(std::unique_ptr<KeySlotCacheAccessor> *out, const void *key, size_t key_size, s32 key2) {
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return this->AllocateFromLru(out, m_high_priority_mru_list, key, key_size, key2);
}
Result Find(std::unique_ptr<KeySlotCacheAccessor> *out, const void *key, size_t key_size, s32 key2) {
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util::unique_lock lk(m_mutex);
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KeySlotCacheEntryList *lists[2] = { std::addressof(m_high_priority_mru_list), std::addressof(m_low_priority_mru_list) };
for (auto list : lists) {
for (auto it = list->begin(); it != list->end(); ++it) {
if (it->Contains(key, key_size, key2)) {
std::unique_ptr accessor = std::make_unique<KeySlotCacheAccessor>(it->GetKeySlotIndex(), std::move(lk));
R_UNLESS(accessor != nullptr, fs::ResultAllocationFailure());
*out = std::move(accessor);
this->UpdateMru(list, it);
return ResultSuccess();
}
}
}
return fs::ResultTargetNotFound();
}
void AddEntry(KeySlotCacheEntry *entry) {
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util::unique_lock lk(m_mutex);
m_low_priority_mru_list.push_front(*entry);
}
private:
Result AllocateFromLru(std::unique_ptr<KeySlotCacheAccessor> *out, KeySlotCacheEntryList &dst_list, const void *key, size_t key_size, s32 key2) {
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util::unique_lock lk(m_mutex);
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KeySlotCacheEntryList &src_list = m_low_priority_mru_list.empty() ? m_high_priority_mru_list : m_low_priority_mru_list;
AMS_ASSERT(!src_list.empty());
auto it = src_list.rbegin();
std::unique_ptr accessor = std::make_unique<KeySlotCacheAccessor>(it->GetKeySlotIndex(), std::move(lk));
*out = std::move(accessor);
it->SetKey(key, key_size, key2);
auto *entry = std::addressof(*it);
src_list.pop_back();
dst_list.push_front(*entry);
return ResultSuccess();
}
void UpdateMru(KeySlotCacheEntryList *list, KeySlotCacheEntryList::iterator it) {
auto *entry = std::addressof(*it);
list->erase(it);
list->push_front(*entry);
}
};
}