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Atmosphere/libraries/libmesosphere/include/mesosphere/kern_k_handle_table.hpp
2022-03-23 09:10:50 -07:00

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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 <mesosphere/kern_common.hpp>
#include <mesosphere/kern_k_auto_object.hpp>
#include <mesosphere/kern_k_spin_lock.hpp>
#include <mesosphere/kern_k_thread.hpp>
#include <mesosphere/kern_k_interrupt_event.hpp>
namespace ams::kern {
constexpr ALWAYS_INLINE util::BitPack32 GetHandleBitPack(ams::svc::Handle handle) {
return util::BitPack32{handle};
}
class KProcess;
class KThread;
class KHandleTable {
NON_COPYABLE(KHandleTable);
NON_MOVEABLE(KHandleTable);
public:
static constexpr size_t MaxTableSize = 1024;
private:
using HandleRawValue = util::BitPack32::Field<0, BITSIZEOF(u32), u32>;
using HandleEncoded = util::BitPack32::Field<0, BITSIZEOF(ams::svc::Handle), ams::svc::Handle>;
using HandleIndex = util::BitPack32::Field<0, 15, u16>;
using HandleLinearId = util::BitPack32::Field<HandleIndex::Next, 15, u16>;
using HandleReserved = util::BitPack32::Field<HandleLinearId::Next, 2, u32>;
static constexpr u16 MinLinearId = 1;
static constexpr u16 MaxLinearId = util::BitPack32{std::numeric_limits<u32>::max()}.Get<HandleLinearId>();
static constexpr ALWAYS_INLINE ams::svc::Handle EncodeHandle(u16 index, u16 linear_id) {
util::BitPack32 pack = {0};
pack.Set<HandleIndex>(index);
pack.Set<HandleLinearId>(linear_id);
pack.Set<HandleReserved>(0);
return pack.Get<HandleEncoded>();
}
union EntryInfo {
u16 linear_id;
s16 next_free_index;
constexpr ALWAYS_INLINE u16 GetLinearId() const { return linear_id; }
constexpr ALWAYS_INLINE s32 GetNextFreeIndex() const { return next_free_index; }
};
private:
EntryInfo m_entry_infos[MaxTableSize];
KAutoObject *m_objects[MaxTableSize];
mutable KSpinLock m_lock;
s32 m_free_head_index;
u16 m_table_size;
u16 m_max_count;
u16 m_next_linear_id;
u16 m_count;
public:
constexpr explicit KHandleTable(util::ConstantInitializeTag) : m_entry_infos(), m_objects(), m_lock(), m_free_head_index(-1), m_table_size(), m_max_count(), m_next_linear_id(MinLinearId), m_count() { /* ... */ }
explicit KHandleTable() : m_lock(), m_free_head_index(-1), m_count() { MESOSPHERE_ASSERT_THIS(); }
constexpr MESOSPHERE_NOINLINE_IF_DEBUG Result Initialize(s32 size) {
MESOSPHERE_ASSERT_THIS();
R_UNLESS(size <= static_cast<s32>(MaxTableSize), svc::ResultOutOfMemory());
/* Initialize all fields. */
m_max_count = 0;
m_table_size = (size <= 0) ? MaxTableSize : size;
m_next_linear_id = MinLinearId;
m_count = 0;
m_free_head_index = -1;
/* Free all entries. */
for (s32 i = 0; i < static_cast<s32>(m_table_size); ++i) {
m_objects[i] = nullptr;
m_entry_infos[i].next_free_index = i - 1;
m_free_head_index = i;
}
R_SUCCEED();
}
constexpr ALWAYS_INLINE size_t GetTableSize() const { return m_table_size; }
constexpr ALWAYS_INLINE size_t GetCount() const { return m_count; }
constexpr ALWAYS_INLINE size_t GetMaxCount() const { return m_max_count; }
MESOSPHERE_NOINLINE_IF_DEBUG Result Finalize();
MESOSPHERE_NOINLINE_IF_DEBUG bool Remove(ams::svc::Handle handle);
template<typename T = KAutoObject>
ALWAYS_INLINE KScopedAutoObject<T> GetObjectWithoutPseudoHandle(ams::svc::Handle handle) const {
/* Lock and look up in table. */
KScopedDisableDispatch dd;
KScopedSpinLock lk(m_lock);
if constexpr (std::is_same<T, KAutoObject>::value) {
return this->GetObjectImpl(handle);
} else {
if (auto *obj = this->GetObjectImpl(handle); AMS_LIKELY(obj != nullptr)) {
return obj->DynamicCast<T*>();
} else {
return nullptr;
}
}
}
template<typename T = KAutoObject>
ALWAYS_INLINE KScopedAutoObject<T> GetObject(ams::svc::Handle handle) const {
MESOSPHERE_ASSERT_THIS();
/* Handle pseudo-handles. */
if constexpr (std::derived_from<KProcess, T>) {
if (handle == ams::svc::PseudoHandle::CurrentProcess) {
auto * const cur_process = GetCurrentProcessPointer();
AMS_ASSUME(cur_process != nullptr);
return cur_process;
}
} else if constexpr (std::derived_from<KThread, T>) {
if (handle == ams::svc::PseudoHandle::CurrentThread) {
auto * const cur_thread = GetCurrentThreadPointer();
AMS_ASSUME(cur_thread != nullptr);
return cur_thread;
}
}
return this->template GetObjectWithoutPseudoHandle<T>(handle);
}
KScopedAutoObject<KAutoObject> GetObjectForIpcWithoutPseudoHandle(ams::svc::Handle handle) const {
/* Lock and look up in table. */
KScopedDisableDispatch dd;
KScopedSpinLock lk(m_lock);
KAutoObject *obj = this->GetObjectImpl(handle);
if (AMS_LIKELY(obj != nullptr)) {
if (AMS_UNLIKELY(obj->DynamicCast<KInterruptEvent *>() != nullptr)) {
return nullptr;
}
}
return obj;
}
ALWAYS_INLINE KScopedAutoObject<KAutoObject> GetObjectForIpc(ams::svc::Handle handle, KThread *cur_thread) const {
/* Handle pseudo-handles. */
AMS_ASSUME(cur_thread != nullptr);
if (handle == ams::svc::PseudoHandle::CurrentProcess) {
auto * const cur_process = static_cast<KAutoObject *>(static_cast<void *>(cur_thread->GetOwnerProcess()));
AMS_ASSUME(cur_process != nullptr);
return cur_process;
}
if (handle == ams::svc::PseudoHandle::CurrentThread) {
return static_cast<KAutoObject *>(cur_thread);
}
return GetObjectForIpcWithoutPseudoHandle(handle);
}
ALWAYS_INLINE KScopedAutoObject<KAutoObject> GetObjectByIndex(ams::svc::Handle *out_handle, size_t index) const {
MESOSPHERE_ASSERT_THIS();
KScopedDisableDispatch dd;
KScopedSpinLock lk(m_lock);
return this->GetObjectByIndexImpl(out_handle, index);
}
MESOSPHERE_NOINLINE_IF_DEBUG Result Reserve(ams::svc::Handle *out_handle);
MESOSPHERE_NOINLINE_IF_DEBUG void Unreserve(ams::svc::Handle handle);
MESOSPHERE_NOINLINE_IF_DEBUG Result Add(ams::svc::Handle *out_handle, KAutoObject *obj);
MESOSPHERE_NOINLINE_IF_DEBUG void Register(ams::svc::Handle handle, KAutoObject *obj);
template<typename T>
ALWAYS_INLINE bool GetMultipleObjects(T **out, const ams::svc::Handle *handles, size_t num_handles) const {
/* Try to convert and open all the handles. */
size_t num_opened;
{
/* Lock the table. */
KScopedDisableDispatch dd;
KScopedSpinLock lk(m_lock);
for (num_opened = 0; num_opened < num_handles; num_opened++) {
/* Get the current handle. */
const auto cur_handle = handles[num_opened];
/* Get the object for the current handle. */
KAutoObject *cur_object = this->GetObjectImpl(cur_handle);
if (AMS_UNLIKELY(cur_object == nullptr)) {
break;
}
/* Cast the current object to the desired type. */
T *cur_t = cur_object->DynamicCast<T*>();
if (AMS_UNLIKELY(cur_t == nullptr)) {
break;
}
/* Open a reference to the current object. */
cur_t->Open();
out[num_opened] = cur_t;
}
}
/* If we converted every object, succeed. */
if (AMS_LIKELY(num_opened == num_handles)) {
return true;
}
/* If we didn't convert entry object, close the ones we opened. */
for (size_t i = 0; i < num_opened; i++) {
out[i]->Close();
}
return false;
}
private:
constexpr ALWAYS_INLINE s32 AllocateEntry() {
MESOSPHERE_ASSERT_THIS();
MESOSPHERE_ASSERT(m_count < m_table_size);
const auto index = m_free_head_index;
m_free_head_index = m_entry_infos[index].GetNextFreeIndex();
m_max_count = std::max(m_max_count, ++m_count);
return index;
}
constexpr ALWAYS_INLINE void FreeEntry(s32 index) {
MESOSPHERE_ASSERT_THIS();
MESOSPHERE_ASSERT(m_count > 0);
m_objects[index] = nullptr;
m_entry_infos[index].next_free_index = m_free_head_index;
m_free_head_index = index;
--m_count;
}
constexpr ALWAYS_INLINE u16 AllocateLinearId() {
const u16 id = m_next_linear_id++;
if (m_next_linear_id > MaxLinearId) {
m_next_linear_id = MinLinearId;
}
return id;
}
constexpr ALWAYS_INLINE bool IsValidHandle(ams::svc::Handle handle) const {
MESOSPHERE_ASSERT_THIS();
/* Unpack the handle. */
const auto handle_pack = GetHandleBitPack(handle);
const auto raw_value = handle_pack.Get<HandleRawValue>();
const auto index = handle_pack.Get<HandleIndex>();
const auto linear_id = handle_pack.Get<HandleLinearId>();
const auto reserved = handle_pack.Get<HandleReserved>();
MESOSPHERE_ASSERT(reserved == 0);
MESOSPHERE_UNUSED(reserved);
/* Validate our indexing information. */
if (AMS_UNLIKELY(raw_value == 0)) {
return false;
}
if (AMS_UNLIKELY(linear_id == 0)) {
return false;
}
if (AMS_UNLIKELY(index >= m_table_size)) {
return false;
}
/* Check that there's an object, and our serial id is correct. */
if (AMS_UNLIKELY(m_objects[index] == nullptr)) {
return false;
}
if (AMS_UNLIKELY(m_entry_infos[index].GetLinearId() != linear_id)) {
return false;
}
return true;
}
constexpr MESOSPHERE_NOINLINE_IF_DEBUG KAutoObject *GetObjectImpl(ams::svc::Handle handle) const {
MESOSPHERE_ASSERT_THIS();
/* Handles must not have reserved bits set. */
const auto handle_pack = GetHandleBitPack(handle);
if (AMS_UNLIKELY(handle_pack.Get<HandleReserved>() != 0)) {
return nullptr;
}
if (AMS_LIKELY(this->IsValidHandle(handle))) {
return m_objects[handle_pack.Get<HandleIndex>()];
} else {
return nullptr;
}
}
constexpr ALWAYS_INLINE KAutoObject *GetObjectByIndexImpl(ams::svc::Handle *out_handle, size_t index) const {
MESOSPHERE_ASSERT_THIS();
/* Index must be in bounds. */
if (AMS_UNLIKELY(index >= m_table_size)) {
return nullptr;
}
/* Ensure entry has an object. */
if (KAutoObject *obj = m_objects[index]; obj != nullptr) {
*out_handle = EncodeHandle(index, m_entry_infos[index].GetLinearId());
return obj;
} else {
return nullptr;
}
}
};
}