6ff5135521
We've had the old kernel capability parser from Citra, however, this is unused code and doesn't actually map to how the kernel on the Switch does it. This introduces the basic functional skeleton for parsing process capabilities.
116 lines
4.4 KiB
C++
116 lines
4.4 KiB
C++
// Copyright 2014 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <array>
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#include <cstddef>
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#include "common/common_types.h"
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#include "core/hle/kernel/object.h"
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#include "core/hle/result.h"
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namespace Kernel {
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enum KernelHandle : Handle {
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InvalidHandle = 0,
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CurrentThread = 0xFFFF8000,
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CurrentProcess = 0xFFFF8001,
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};
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/**
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* This class allows the creation of Handles, which are references to objects that can be tested
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* for validity and looked up. Here they are used to pass references to kernel objects to/from the
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* emulated process. it has been designed so that it follows the same handle format and has
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* approximately the same restrictions as the handle manager in the CTR-OS.
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*
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* Handles contain two sub-fields: a slot index (bits 31:15) and a generation value (bits 14:0).
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* The slot index is used to index into the arrays in this class to access the data corresponding
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* to the Handle.
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*
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* To prevent accidental use of a freed Handle whose slot has already been reused, a global counter
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* is kept and incremented every time a Handle is created. This is the Handle's "generation". The
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* value of the counter is stored into the Handle as well as in the handle table (in the
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* "generations" array). When looking up a handle, the Handle's generation must match with the
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* value stored on the class, otherwise the Handle is considered invalid.
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*
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* To find free slots when allocating a Handle without needing to scan the entire object array, the
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* generations field of unallocated slots is re-purposed as a linked list of indices to free slots.
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* When a Handle is created, an index is popped off the list and used for the new Handle. When it
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* is destroyed, it is again pushed onto the list to be re-used by the next allocation. It is
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* likely that this allocation strategy differs from the one used in CTR-OS, but this hasn't been
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* verified and isn't likely to cause any problems.
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*/
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class HandleTable final : NonCopyable {
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public:
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/// This is the maximum limit of handles allowed per process in Horizon
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static constexpr std::size_t MAX_COUNT = 1024;
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HandleTable();
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~HandleTable();
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/**
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* Allocates a handle for the given object.
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* @return The created Handle or one of the following errors:
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* - `ERR_HANDLE_TABLE_FULL`: the maximum number of handles has been exceeded.
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*/
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ResultVal<Handle> Create(SharedPtr<Object> obj);
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/**
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* Returns a new handle that points to the same object as the passed in handle.
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* @return The duplicated Handle or one of the following errors:
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* - `ERR_INVALID_HANDLE`: an invalid handle was passed in.
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* - Any errors returned by `Create()`.
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*/
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ResultVal<Handle> Duplicate(Handle handle);
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/**
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* Closes a handle, removing it from the table and decreasing the object's ref-count.
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* @return `RESULT_SUCCESS` or one of the following errors:
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* - `ERR_INVALID_HANDLE`: an invalid handle was passed in.
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*/
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ResultCode Close(Handle handle);
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/// Checks if a handle is valid and points to an existing object.
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bool IsValid(Handle handle) const;
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/**
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* Looks up a handle.
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* @return Pointer to the looked-up object, or `nullptr` if the handle is not valid.
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*/
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SharedPtr<Object> GetGeneric(Handle handle) const;
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/**
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* Looks up a handle while verifying its type.
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* @return Pointer to the looked-up object, or `nullptr` if the handle is not valid or its
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* type differs from the requested one.
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*/
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template <class T>
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SharedPtr<T> Get(Handle handle) const {
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return DynamicObjectCast<T>(GetGeneric(handle));
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}
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/// Closes all handles held in this table.
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void Clear();
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private:
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/// Stores the Object referenced by the handle or null if the slot is empty.
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std::array<SharedPtr<Object>, MAX_COUNT> objects;
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/**
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* The value of `next_generation` when the handle was created, used to check for validity. For
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* empty slots, contains the index of the next free slot in the list.
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*/
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std::array<u16, MAX_COUNT> generations;
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/**
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* Global counter of the number of created handles. Stored in `generations` when a handle is
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* created, and wraps around to 1 when it hits 0x8000.
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*/
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u16 next_generation;
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/// Head of the free slots linked list.
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u16 next_free_slot;
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};
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} // namespace Kernel
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