windows-user-space-emulator/src/windows_emulator/syscalls.cpp

#include "std_include.hpp"
#include "syscalls.hpp"
#include "context_frame.hpp"

struct syscall_context
{
	x64_emulator& emu;
	process_context& proc;
	mutable bool write_status;
};

namespace
{
	uint64_t get_syscall_argument(x64_emulator& emu, const size_t index)
	{
		switch (index)
		{
		case 0:
			return emu.reg(x64_register::r10);
		case 1:
			return emu.reg(x64_register::rdx);
		case 2:
			return emu.reg(x64_register::r8);
		case 3:
			return emu.reg(x64_register::r9);
		default:
			return emu.read_stack(index + 1);
		}
	}

	bool is_uppercase(const char character)
	{
		return toupper(character) == character;
	}

	bool is_syscall(const std::string_view name)
	{
		return name.starts_with("Nt") && name.size() > 3 && is_uppercase(name[2]);
	}

	std::vector<std::string> find_syscalls(const exported_symbols& exports)
	{
		// Makes use of the fact that order of Nt* function addresses
		// is equal to the order of syscall IDs.
		// So first Nt* function is the first syscall with ID 0

		std::map<uint64_t, size_t> reference_count{};
		std::map<uint64_t, std::string> ordered_syscalls{};

		for (const auto& symbol : exports)
		{
			if (is_syscall(symbol.name))
			{
				++reference_count[symbol.address];
				ordered_syscalls[symbol.address] = symbol.name;
			}
		}

		std::vector<std::string> syscalls{};
		syscalls.reserve(ordered_syscalls.size());

		for (auto& syscall : ordered_syscalls)
		{
			if (reference_count[syscall.first] == 1)
			{
				syscalls.push_back(std::move(syscall.second));
			}
			else
			{
				printf("Skipping %s\n", syscall.second.c_str());
			}
		}

		return syscalls;
	}

	uint64_t get_syscall_id(const std::vector<std::string>& ntdll_syscalls,
	                        const std::vector<std::string>& win32u_syscalls, const std::string_view name)
	{
		for (size_t i = 0; i < ntdll_syscalls.size(); ++i)
		{
			if (ntdll_syscalls[i] == name)
			{
				return i;
			}
		}

		for (size_t i = 0; i < win32u_syscalls.size(); ++i)
		{
			if (win32u_syscalls[i] == name)
			{
				return i + 0x1000;
			}
		}

		throw std::runtime_error("Unable to determine syscall id: " + std::string(name));
	}

	std::wstring read_unicode_string(emulator& emu, const emulator_object<UNICODE_STRING> uc_string)
	{
		static_assert(offsetof(UNICODE_STRING, Length) == 0);
		static_assert(offsetof(UNICODE_STRING, MaximumLength) == 2);
		static_assert(offsetof(UNICODE_STRING, Buffer) == 8);
		static_assert(sizeof(UNICODE_STRING) == 16);

		const auto ucs = uc_string.read();

		std::wstring result{};
		result.resize(ucs.Length / 2);

		emu.read_memory(reinterpret_cast<uint64_t>(ucs.Buffer), result.data(), ucs.Length);

		return result;
	}

	std::wstring read_unicode_string(emulator& emu, const PUNICODE_STRING uc_string)
	{
		return read_unicode_string(emu, emulator_object<UNICODE_STRING>{emu, uc_string});
	}

	template <typename T>
		requires(std::is_integral_v<T> || std::is_enum_v<T>)
	T resolve_argument(x64_emulator& emu, const size_t index)
	{
		const auto arg = get_syscall_argument(emu, index);
		return static_cast<T>(arg);
	}

	template <typename T>
		requires(std::is_same_v<T, emulator_object<typename T::value_type>>)
	T resolve_argument(x64_emulator& emu, const size_t index)
	{
		const auto arg = get_syscall_argument(emu, index);
		return T(emu, arg);
	}

	template <typename T>
	T resolve_indexed_argument(x64_emulator& emu, size_t& index)
	{
		return resolve_argument<T>(emu, index++);
	}

	void write_status(const syscall_context& c, const NTSTATUS status, const uint64_t initial_ip)
	{
		if (c.write_status)
		{
			c.emu.reg<uint64_t>(x64_register::rax, static_cast<uint64_t>(status));
		}

		const auto new_ip = c.emu.read_instruction_pointer();
		if (initial_ip != new_ip)
		{
			c.emu.reg(x64_register::rip, new_ip - 2);
		}
	}

	void forward(const syscall_context& c, NTSTATUS (*handler)())
	{
		const auto ip = c.emu.read_instruction_pointer();

		const auto ret = handler();
		write_status(c, ret, ip);
	}

	template <typename... Args>
	void forward(const syscall_context& c, NTSTATUS (*handler)(const syscall_context&, Args...))
	{
		const auto ip = c.emu.read_instruction_pointer();

		size_t index = 0;
		std::tuple<const syscall_context&, Args...> func_args
		{
			c,
			resolve_indexed_argument<std::remove_cv_t<std::remove_reference_t<Args>>>(c.emu, index)...
		};

		const auto ret = std::apply(handler, std::move(func_args));
		write_status(c, ret, ip);
	}

	NTSTATUS handle_NtQueryPerformanceCounter(const syscall_context&,
	                                          const emulator_object<LARGE_INTEGER> performance_counter,
	                                          const emulator_object<LARGE_INTEGER> performance_frequency)
	{
		try
		{
			if (performance_counter)
			{
				performance_counter.access([](LARGE_INTEGER& value)
				{
					QueryPerformanceCounter(&value);
				});
			}

			if (performance_frequency)
			{
				performance_frequency.access([](LARGE_INTEGER& value)
				{
					QueryPerformanceFrequency(&value);
				});
			}

			return STATUS_SUCCESS;
		}
		catch (...)
		{
			return STATUS_ACCESS_VIOLATION;
		}
	}

	NTSTATUS handle_NtManageHotPatch()
	{
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtCreateWorkerFactory()
	{
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtOpenKey()
	{
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtSetInformationThread(const syscall_context& c, const uint64_t /*thread_handle*/,
	                                       const THREADINFOCLASS info_class,
	                                       const uint64_t /*thread_information*/,
	                                       const uint32_t /*thread_information_length*/)
	{
		if (info_class == ThreadSchedulerSharedDataSlot)
		{
			return STATUS_SUCCESS;
		}

		printf("Unsupported thread info class: %X\n", info_class);
		c.emu.stop();
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtSetEvent(const syscall_context& c, const uint64_t handle,
	                           const emulator_object<LONG> previous_state)
	{
		const auto entry = c.proc.events.get(handle);
		if (!entry)
		{
			return STATUS_INVALID_HANDLE;
		}

		if (previous_state.value())
		{
			previous_state.write(entry->signaled ? 1ULL : 0ULL);
		}

		entry->signaled = true;
		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtClose(const syscall_context& c, const uint64_t handle)
	{
		const auto value = get_handle_value(handle);
		if (value.is_pseudo)
		{
			return STATUS_SUCCESS;
		}

		if (value.type == handle_types::event && c.proc.events.erase(handle))
		{
			return STATUS_SUCCESS;
		}

		if (value.type == handle_types::file && c.proc.files.erase(handle))
		{
			return STATUS_SUCCESS;
		}

		if (value.type == handle_types::semaphore && c.proc.semaphores.erase(handle))
		{
			return STATUS_SUCCESS;
		}

		return STATUS_INVALID_HANDLE;
	}

	NTSTATUS handle_NtTraceEvent()
	{
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtOpenThreadToken()
	{
		return STATUS_NO_TOKEN;
	}

	NTSTATUS handle_NtCreateEvent(const syscall_context& c, const emulator_object<uint64_t> event_handle,
	                              const ACCESS_MASK /*desired_access*/, const uint64_t object_attributes,
	                              const EVENT_TYPE event_type, const BOOLEAN initial_state)
	{
		if (object_attributes)
		{
			puts("Unsupported object attributes");
			c.emu.stop();
			return STATUS_NOT_SUPPORTED;
		}

		event e{initial_state != FALSE, event_type};
		const auto handle = c.proc.events.store(std::move(e));
		event_handle.write(handle.bits);

		static_assert(sizeof(EVENT_TYPE) == sizeof(uint32_t));
		static_assert(sizeof(ACCESS_MASK) == sizeof(uint32_t));

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtQueryVolumeInformationFile(const syscall_context& c, uint64_t /*file_handle*/,
	                                             uint64_t /*io_status_block*/, uint64_t fs_information,
	                                             ULONG /*length*/,
	                                             FS_INFORMATION_CLASS fs_information_class)
	{
		if (fs_information_class != FileFsDeviceInformation)
		{
			printf("Unsupported fs info class: %X\n", fs_information_class);
			c.emu.stop();
			return STATUS_NOT_SUPPORTED;
		}

		const emulator_object<FILE_FS_DEVICE_INFORMATION> info_obj{c.emu, fs_information};
		info_obj.access([&](FILE_FS_DEVICE_INFORMATION& info)
		{
			info.DeviceType = FILE_DEVICE_DISK;
			info.Characteristics = 0x20020;
		});

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtOpenFile(const syscall_context& c,
	                           const emulator_object<uint64_t> file_handle,
	                           const ACCESS_MASK desired_access,
	                           const emulator_object<OBJECT_ATTRIBUTES> object_attributes,
	                           const emulator_object<IO_STATUS_BLOCK> /*io_status_block*/,
	                           const ULONG share_access,
	                           const ULONG open_options)
	{
		file f{};
		const auto attributes = object_attributes.read();
		f.name = read_unicode_string(c.emu, attributes.ObjectName);

		UNICODE_STRING string{};
		string.Buffer = f.name.data();
		string.Length = static_cast<uint16_t>(f.name.size() * 2);
		string.MaximumLength = string.Length;

		OBJECT_ATTRIBUTES new_attributes{};
		new_attributes.ObjectName = &string;
		new_attributes.Length = sizeof(new_attributes);

		HANDLE h{};
		IO_STATUS_BLOCK status_block{};

		const auto res = NtOpenFile(&h, desired_access, &new_attributes, &status_block, share_access, open_options);
		if (res != STATUS_SUCCESS)
		{
			return res;
		}

		f.handle = h;

		const auto handle = c.proc.files.store(std::move(f));
		file_handle.write(handle.bits);

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtOpenSection(const syscall_context& c, const emulator_object<uint64_t> section_handle,
	                              const ACCESS_MASK /*desired_access*/,
	                              const emulator_object<OBJECT_ATTRIBUTES> object_attributes)
	{
		const auto attributes = object_attributes.read();

		auto filename = read_unicode_string(c.emu, attributes.ObjectName);
		printf("Open section: %S\n", filename.c_str());

		if (filename == L"\\Windows\\SharedSection")
		{
			section_handle.write(SHARED_SECTION.bits);
			return STATUS_SUCCESS;
		}

		if (reinterpret_cast<uint64_t>(attributes.RootDirectory) != KNOWN_DLLS_DIRECTORY)
		{
			puts("Unsupported section");
			c.emu.stop();
			return STATUS_NOT_SUPPORTED;
		}

		if (filename.starts_with(L"api-ms-"))
		{
			filename = L"C:\\WINDOWS\\System32\\downlevel\\" + filename;
		}
		else
		{
			filename = L"C:\\WINDOWS\\System32\\" + filename;
		}

		if (!std::filesystem::exists(filename))
		{
			return STATUS_FILE_INVALID;
		}

		const auto handle = c.proc.files.store(file{{}, std::move(filename)});
		section_handle.write(handle.bits);

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtMapViewOfSection(const syscall_context& c, uint64_t section_handle, uint64_t process_handle,
	                                   emulator_object<uint64_t> base_address, ULONG_PTR /*zero_bits*/,
	                                   SIZE_T /*commit_size*/,
	                                   const emulator_object<LARGE_INTEGER> /*section_offset*/,
	                                   const emulator_object<SIZE_T> view_size, SECTION_INHERIT /*inherit_disposition*/,
	                                   ULONG /*allocation_type*/, ULONG /*win32_protect*/)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_INVALID_HANDLE;
		}

		const auto section_entry = c.proc.files.get(section_handle);
		if (!section_entry)
		{
			return STATUS_INVALID_HANDLE;
		}

		const auto binary = c.proc.module_manager.map_module(section_entry->name);
		if (!binary)
		{
			return STATUS_FILE_INVALID;
		}

		if (view_size.value())
		{
			view_size.write(binary->size_of_image);
		}

		base_address.write(binary->image_base);

		return STATUS_SUCCESS;
	}


	NTSTATUS handle_NtCreateIoCompletion(const syscall_context& c, const emulator_object<uint64_t> event_handle,
	                                     const ACCESS_MASK desired_access, const uint64_t object_attributes,
	                                     uint32_t /*number_of_concurrent_threads*/)
	{
		return handle_NtCreateEvent(c, event_handle, desired_access, object_attributes, NotificationEvent, FALSE);
	}

	NTSTATUS handle_NtCreateWaitCompletionPacket(const syscall_context& c, const emulator_object<uint64_t> event_handle,
	                                             const ACCESS_MASK desired_access, const uint64_t object_attributes)
	{
		return handle_NtCreateEvent(c, event_handle, desired_access, object_attributes, NotificationEvent, FALSE);
	}

	NTSTATUS handle_NtQueryVirtualMemory(const syscall_context& c, const uint64_t process_handle,
	                                     const uint64_t base_address, const uint32_t info_class,
	                                     const uint64_t memory_information, const uint32_t memory_information_length,
	                                     const emulator_object<uint32_t> return_length)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == MemoryWorkingSetExInformation
			|| info_class == MemoryImageExtensionInformation)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == MemoryBasicInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(MEMORY_BASIC_INFORMATION));
			}

			if (memory_information_length != sizeof(MEMORY_BASIC_INFORMATION))
			{
				return STATUS_BUFFER_OVERFLOW;
			}

			const emulator_object<MEMORY_BASIC_INFORMATION> info{c.emu, memory_information};

			info.access([&](MEMORY_BASIC_INFORMATION& image_info)
			{
				const auto region_info = c.emu.get_region_info(base_address);

				assert(!region_info.is_committed || region_info.is_reserved);

				image_info.BaseAddress = reinterpret_cast<void*>(region_info.start);
				image_info.AllocationBase = reinterpret_cast<void*>(region_info.allocation_base);
				image_info.AllocationProtect = 0;
				image_info.PartitionId = 0;
				image_info.RegionSize = region_info.length;
				image_info.State = region_info.is_committed
					                   ? MEM_COMMIT
					                   : (region_info.is_reserved
						                      ? MEM_RESERVE
						                      : MEM_FREE);
				image_info.Protect = map_emulator_to_nt_protection(region_info.pemissions);
				image_info.Type = MEM_PRIVATE;
			});

			return STATUS_SUCCESS;
		}

		if (info_class == MemoryImageInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(MEMORY_IMAGE_INFORMATION));
			}

			if (memory_information_length != sizeof(MEMORY_IMAGE_INFORMATION))
			{
				return STATUS_BUFFER_OVERFLOW;
			}

			const auto mod = c.proc.module_manager.find_by_address(base_address);
			if (!mod)
			{
				printf("Bad address for memory image request: %llX\n", base_address);
				return STATUS_INVALID_ADDRESS;
			}

			const emulator_object<MEMORY_IMAGE_INFORMATION> info{c.emu, memory_information};

			info.access([&](MEMORY_IMAGE_INFORMATION& image_info)
			{
				image_info.ImageBase = reinterpret_cast<void*>(mod->image_base);
				image_info.SizeOfImage = mod->size_of_image;
			});

			return STATUS_SUCCESS;
		}

		printf("Unsupported memory info class: %X\n", info_class);
		c.emu.stop();
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtQuerySystemInformation(const syscall_context& c, const uint32_t info_class,
	                                         const uint64_t system_information,
	                                         const uint32_t system_information_length,
	                                         const emulator_object<uint32_t> return_length)
	{
		if (info_class == SystemFlushInformation
			|| info_class == SystemHypervisorSharedPageInformation
		)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == SystemTimeOfDayInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(SYSTEM_TIMEOFDAY_INFORMATION));
			}

			if (system_information_length != sizeof(SYSTEM_TIMEOFDAY_INFORMATION))
			{
				return STATUS_BUFFER_TOO_SMALL;
			}

			const emulator_object<SYSTEM_TIMEOFDAY_INFORMATION> info_obj{c.emu, system_information};

			info_obj.access([&](SYSTEM_TIMEOFDAY_INFORMATION& info)
			{
				info.BootTime.QuadPart = 0;
				// TODO: Fill
			});

			return STATUS_SUCCESS;
		}

		if (info_class == SystemRangeStartInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(SYSTEM_RANGE_START_INFORMATION));
			}

			if (system_information_length != sizeof(SYSTEM_RANGE_START_INFORMATION))
			{
				return STATUS_BUFFER_TOO_SMALL;
			}

			const emulator_object<SYSTEM_RANGE_START_INFORMATION> info_obj{c.emu, system_information};

			info_obj.access([&](SYSTEM_RANGE_START_INFORMATION& info)
			{
				info.SystemRangeStart = 0xFFFF800000000000;
			});

			return STATUS_SUCCESS;
		}

		if (info_class == SystemProcessorInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(SYSTEM_PROCESSOR_INFORMATION));
			}

			if (system_information_length != sizeof(SYSTEM_PROCESSOR_INFORMATION))
			{
				return STATUS_BUFFER_TOO_SMALL;
			}

			const emulator_object<SYSTEM_PROCESSOR_INFORMATION> info_obj{c.emu, system_information};

			info_obj.access([&](SYSTEM_PROCESSOR_INFORMATION& info)
			{
				memset(&info, 0, sizeof(info));
				info.MaximumProcessors = 2;
				info.ProcessorArchitecture = PROCESSOR_ARCHITECTURE_AMD64;
			});

			return STATUS_SUCCESS;
		}

		if (info_class == SystemNumaProcessorMap)
		{
			if (return_length)
			{
				return_length.write(sizeof(SYSTEM_NUMA_INFORMATION));
			}

			if (system_information_length != sizeof(SYSTEM_NUMA_INFORMATION))
			{
				return STATUS_BUFFER_TOO_SMALL;
			}

			const emulator_object<SYSTEM_NUMA_INFORMATION> info_obj{c.emu, system_information};

			info_obj.access([&](SYSTEM_NUMA_INFORMATION& info)
			{
				memset(&info, 0, sizeof(info));
				info.ActiveProcessorsGroupAffinity->Mask = 0xFFF;
				info.AvailableMemory[0] = 0xFFF;
				info.Pad[0] = 0xFFF;
			});

			return STATUS_SUCCESS;
		}

		if (info_class != SystemBasicInformation && info_class != SystemEmulationBasicInformation)
		{
			printf("Unsupported system info class: %X\n", info_class);
			c.emu.stop();
			return STATUS_NOT_SUPPORTED;
		}

		if (return_length)
		{
			return_length.write(sizeof(SYSTEM_BASIC_INFORMATION));
		}

		if (system_information_length != sizeof(SYSTEM_BASIC_INFORMATION))
		{
			return STATUS_BUFFER_TOO_SMALL;
		}

		const emulator_object<SYSTEM_BASIC_INFORMATION> info{c.emu, system_information};

		info.access([&](SYSTEM_BASIC_INFORMATION& basic_info)
		{
			basic_info.Reserved = 0;
			basic_info.TimerResolution = 0x0002625a;
			basic_info.PageSize = 0x1000;
			basic_info.LowestPhysicalPageNumber = 0x00000001;
			basic_info.HighestPhysicalPageNumber = 0x00c9c7ff;
			basic_info.AllocationGranularity = 0x10000;
			basic_info.MinimumUserModeAddress = 0x0000000000010000;
			basic_info.MaximumUserModeAddress = 0x00007ffffffeffff;
			basic_info.ActiveProcessorsAffinityMask = 0x0000000000000fff;
			basic_info.NumberOfProcessors = 1;
		});

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtQuerySystemInformationEx(const syscall_context& c, const uint32_t info_class,
	                                           const uint64_t input_buffer,
	                                           const uint32_t input_buffer_length,
	                                           const uint64_t system_information,
	                                           const uint32_t system_information_length,
	                                           const emulator_object<uint32_t> return_length)
	{
		if (info_class == SystemFlushInformation
			|| info_class == SystemFeatureConfigurationInformation
			|| info_class == SystemFeatureConfigurationSectionInformation)
		{
			printf("Unsupported, but allowed system info class: %X\n", info_class);
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == SystemLogicalProcessorAndGroupInformation)
		{
			void* buffer = calloc(1, input_buffer_length);
			void* res_buff = calloc(1, system_information_length);
			c.emu.read_memory(input_buffer, buffer, input_buffer_length);

			NTSTATUS code = STATUS_SUCCESS;

			return_length.access([&](uint32_t& len)
			{
				code = NtQuerySystemInformationEx(static_cast<SYSTEM_INFORMATION_CLASS>(info_class), buffer,
				                                  input_buffer_length,
				                                  res_buff,
				                                  system_information_length, reinterpret_cast<ULONG*>(&len));
			});

			if (code == 0)
			{
				c.emu.write_memory(system_information, res_buff, return_length.read());
			}

			free(buffer);
			free(res_buff);

			return code;
		}

		if (info_class != SystemBasicInformation && info_class != SystemEmulationBasicInformation)
		{
			printf("Unsupported system info ex class: %X\n", info_class);
			c.emu.stop();
			return STATUS_NOT_SUPPORTED;
		}

		if (return_length)
		{
			return_length.write(sizeof(SYSTEM_BASIC_INFORMATION));
		}

		if (system_information_length != sizeof(SYSTEM_BASIC_INFORMATION))
		{
			return STATUS_BUFFER_TOO_SMALL;
		}

		const emulator_object<SYSTEM_BASIC_INFORMATION> info{c.emu, system_information};

		info.access([&](SYSTEM_BASIC_INFORMATION& basic_info)
		{
			basic_info.Reserved = 0;
			basic_info.TimerResolution = 0x0002625a;
			basic_info.PageSize = 0x1000;
			basic_info.LowestPhysicalPageNumber = 0x00000001;
			basic_info.HighestPhysicalPageNumber = 0x00c9c7ff;
			basic_info.AllocationGranularity = 0x10000;
			basic_info.MinimumUserModeAddress = 0x0000000000010000;
			basic_info.MaximumUserModeAddress = 0x00007ffffffeffff;
			basic_info.ActiveProcessorsAffinityMask = 0x0000000000000fff;
			basic_info.NumberOfProcessors = 1;
		});

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtQueryInformationProcess(const syscall_context& c, const uint64_t process_handle,
	                                          const uint32_t info_class, const uint64_t process_information,
	                                          const uint32_t process_information_length,
	                                          const emulator_object<uint32_t> return_length)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == ProcessCookie)
		{
			if (return_length)
			{
				return_length.write(sizeof(uint32_t));
			}

			if (process_information_length != sizeof(uint32_t))
			{
				return STATUS_BUFFER_OVERFLOW;
			}

			const emulator_object<uint32_t> info{c.emu, process_information};
			info.write(0x01234567);

			return STATUS_SUCCESS;
		}

		if (info_class == ProcessDebugPort)
		{
			if (return_length)
			{
				return_length.write(sizeof(DWORD_PTR));
			}

			if (process_information_length != sizeof(DWORD_PTR))
			{
				return STATUS_BUFFER_OVERFLOW;
			}

			const emulator_object<DWORD_PTR> info{c.emu, process_information};
			info.write(0);

			return STATUS_SUCCESS;
		}

		if (info_class == ProcessEnclaveInformation)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == ProcessBasicInformation)
		{
			if (return_length)
			{
				return_length.write(sizeof(PROCESS_BASIC_INFORMATION));
			}

			if (process_information_length != sizeof(PROCESS_BASIC_INFORMATION))
			{
				return STATUS_BUFFER_OVERFLOW;
			}

			const emulator_object<PROCESS_BASIC_INFORMATION> info{c.emu, process_information};
			info.access([&](PROCESS_BASIC_INFORMATION& basic_info)
			{
				basic_info.PebBaseAddress = c.proc.peb.ptr();
				basic_info.UniqueProcessId = reinterpret_cast<HANDLE>(1);
			});

			return STATUS_SUCCESS;
		}

		printf("Unsupported process info class: %X\n", info_class);
		c.emu.stop();

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtSetInformationProcess(const syscall_context& c, const uint64_t process_handle,
	                                        const uint32_t info_class, const uint64_t /*process_information*/,
	                                        const uint32_t /*process_information_length*/)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		if (info_class == ProcessSchedulerSharedData
			|| info_class == ProcessTlsInformation
			|| info_class == ProcessConsoleHostProcess
			|| info_class == ProcessRaiseUMExceptionOnInvalidHandleClose)
		{
			return STATUS_SUCCESS;
		}

		printf("Unsupported info process class: %X\n", info_class);
		c.emu.stop();

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtApphelpCacheControl()
	{
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtProtectVirtualMemory(const syscall_context& c, const uint64_t process_handle,
	                                       const emulator_object<uint64_t> base_address,
	                                       const emulator_object<uint32_t> bytes_to_protect,
	                                       const uint32_t protection,
	                                       const emulator_object<uint32_t> old_protection)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		const auto orig_start = base_address.read();
		const auto orig_length = bytes_to_protect.read();

		const auto aligned_start = page_align_down(orig_start);
		const auto aligned_length = page_align_up(orig_start + orig_length) - aligned_start;

		base_address.write(aligned_start);
		bytes_to_protect.write(static_cast<uint32_t>(aligned_length));

		const auto requested_protection = map_nt_to_emulator_protection(protection);

		printf("Changing protection at %llX-%llX to %s\n", aligned_start, aligned_start + aligned_length,
		       get_permission_string(requested_protection).c_str());

		memory_permission old_protection_value{};
		c.emu.protect_memory(aligned_start, aligned_length, requested_protection, &old_protection_value);

		const auto current_protection = map_emulator_to_nt_protection(old_protection_value);
		old_protection.write(current_protection);

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtOpenDirectoryObject(const syscall_context& c,
	                                      const emulator_object<uint64_t> directory_handle,
	                                      const ACCESS_MASK /*desired_access*/,
	                                      const emulator_object<OBJECT_ATTRIBUTES> object_attributes)
	{
		const auto attributes = object_attributes.read();
		const auto object_name = read_unicode_string(c.emu, attributes.ObjectName);

		if (object_name == L"\\KnownDlls")
		{
			directory_handle.write(KNOWN_DLLS_DIRECTORY.bits);
			return STATUS_SUCCESS;
		}

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtOpenSymbolicLinkObject(const syscall_context& c, const emulator_object<uint64_t> link_handle,
	                                         ACCESS_MASK /*desired_access*/,
	                                         const emulator_object<OBJECT_ATTRIBUTES> object_attributes)
	{
		const auto attributes = object_attributes.read();
		const auto object_name = read_unicode_string(c.emu, attributes.ObjectName);

		if (object_name == L"KnownDllPath")
		{
			link_handle.write(KNOWN_DLLS_SYMLINK.bits);
			return STATUS_SUCCESS;
		}

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS WINAPI handle_NtQuerySymbolicLinkObject(const syscall_context& c, const uint64_t link_handle,
	                                                 const emulator_object<UNICODE_STRING> link_target,
	                                                 const emulator_object<ULONG> returned_length)
	{
		if (link_handle == KNOWN_DLLS_SYMLINK)
		{
			constexpr std::wstring_view system32 = L"C:\\WINDOWS\\System32";
			constexpr auto str_length = system32.size() * 2;
			constexpr auto max_length = str_length + 2;

			returned_length.write(max_length);

			bool too_small = false;
			link_target.access([&](UNICODE_STRING& str)
			{
				if (str.MaximumLength < max_length)
				{
					too_small = true;
					return;
				}

				str.Length = str_length;
				c.emu.write_memory(reinterpret_cast<uint64_t>(str.Buffer), system32.data(), max_length);
			});

			return too_small
				       ? STATUS_BUFFER_TOO_SMALL
				       : STATUS_SUCCESS;
		}

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtAllocateVirtualMemoryEx(const syscall_context& c, const uint64_t process_handle,
	                                          const emulator_object<uint64_t> base_address,
	                                          const emulator_object<uint64_t> bytes_to_allocate,
	                                          const uint32_t allocation_type,
	                                          const uint32_t page_protection)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		const auto allocation_bytes = bytes_to_allocate.read();

		const auto protection = map_nt_to_emulator_protection(page_protection);

		auto potential_base = base_address.read();
		if (!potential_base)
		{
			potential_base = c.emu.find_free_allocation_base(allocation_bytes);
		}

		if (!potential_base)
		{
			return STATUS_MEMORY_NOT_ALLOCATED;
		}

		base_address.write(potential_base);

		const bool reserve = allocation_type & MEM_RESERVE;
		const bool commit = allocation_type & MEM_COMMIT;

		if ((allocation_type & ~(MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN)) || (!commit && !reserve))
		{
			throw std::runtime_error("Unsupported allocation type!");
		}

		if (commit && !reserve)
		{
			return c.emu.commit_memory(potential_base, allocation_bytes, protection)
				       ? STATUS_SUCCESS
				       : STATUS_MEMORY_NOT_ALLOCATED;
		}

		return c.emu.allocate_memory(potential_base, allocation_bytes, protection, !commit)
			       ? STATUS_SUCCESS
			       : STATUS_MEMORY_NOT_ALLOCATED;
	}

	NTSTATUS handle_NtAllocateVirtualMemory(const syscall_context& c, const uint64_t process_handle,
	                                        const emulator_object<uint64_t> base_address,
	                                        uint64_t /*zero_bits*/,
	                                        const emulator_object<uint64_t> bytes_to_allocate,
	                                        const uint32_t allocation_type, const uint32_t page_protection)
	{
		return handle_NtAllocateVirtualMemoryEx(c, process_handle, base_address, bytes_to_allocate, allocation_type,
		                                        page_protection);
	}

	NTSTATUS handle_NtFreeVirtualMemory(const syscall_context& c, const uint64_t process_handle,
	                                    const emulator_object<uint64_t> base_address,
	                                    const emulator_object<uint64_t> bytes_to_allocate, uint32_t free_type)
	{
		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		const auto allocation_base = base_address.read();
		const auto allocation_size = bytes_to_allocate.read();

		if (free_type & MEM_RELEASE)
		{
			return c.emu.release_memory(allocation_base, allocation_size)
				       ? STATUS_SUCCESS
				       : STATUS_MEMORY_NOT_ALLOCATED;
		}

		if (free_type & MEM_DECOMMIT)
		{
			return c.emu.decommit_memory(allocation_base, allocation_size)
				       ? STATUS_SUCCESS
				       : STATUS_MEMORY_NOT_ALLOCATED;
		}

		throw std::runtime_error("Bad free type");
	}

	NTSTATUS handle_NtCreateSection(const syscall_context& /*c*/, const emulator_object<uint64_t> /*section_handle*/,
	                                const ACCESS_MASK /*desired_access*/,
	                                const emulator_object<OBJECT_ATTRIBUTES> /*object_attributes*/,
	                                const emulator_object<ULARGE_INTEGER> /*maximum_size*/,
	                                const ULONG /*section_page_protection*/, const ULONG /*allocation_attributes*/,
	                                const uint64_t /*file_handle*/)
	{
		puts("NtCreateSection not supported");
		//c.emu.stop();
		//const auto attributes = object_attributes.read();
		//const auto object_name = read_unicode_string(c.emu, attributes.ObjectName);

		/*section_handle.write(SHARED_SECTION.bits);

		maximum_size.access([](ULARGE_INTEGER& large_int)
		{
			large_int.QuadPart = page_align_up(large_int.QuadPart);
		});*/

		//return STATUS_SUCCESS;
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtConnectPort(const syscall_context& /*c*/)
	{
		puts("NtConnectPort not supported");
		//c.emu.stop();

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtReadVirtualMemory(const syscall_context& c, uint64_t process_handle, uint64_t base_address,
	                                    uint64_t buffer, ULONG number_of_bytes_to_read,
	                                    const emulator_object<ULONG> number_of_bytes_read)
	{
		number_of_bytes_read.write(0);

		if (process_handle != ~0ULL)
		{
			return STATUS_NOT_SUPPORTED;
		}

		std::vector<uint8_t> memory{};
		memory.resize(number_of_bytes_read);

		if (!c.emu.try_read_memory(base_address, memory.data(), memory.size()))
		{
			return STATUS_INVALID_ADDRESS;
		}

		c.emu.write_memory(buffer, memory.data(), memory.size());
		number_of_bytes_read.write(number_of_bytes_to_read);
		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtDeviceIoControlFile()
	{
		puts("NtDeviceIoControlFile not supported");
		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtQueryWnfStateData()
	{
		puts("NtQueryWnfStateData not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtOpenProcessToken()
	{
		puts("NtOpenProcessToken not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtQuerySecurityAttributesToken()
	{
		puts("NtQuerySecurityAttributesToken not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtQueryLicenseValue()
	{
		puts("NtQueryLicenseValue not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtTestAlert()
	{
		puts("NtTestAlert not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtQueryInformationToken()
	{
		puts("NtQueryInformationToken not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtDxgkIsFeatureEnabled()
	{
		puts("NtDxgkIsFeatureEnabled not supported");
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtContinue(const syscall_context& c, const emulator_object<CONTEXT> thread_context,
	                           const BOOLEAN /*raise_alert*/)
	{
		c.write_status = false;

		const auto context = thread_context.read();
		context_frame::restore(c.emu, context);

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtTerminateProcess(const syscall_context& c, const uint64_t process_handle,
	                                   NTSTATUS /*exit_status*/)
	{
		if (process_handle == 0)
		{
			return STATUS_SUCCESS;
		}

		if (process_handle == ~0ULL)
		{
			c.emu.stop();
			return STATUS_SUCCESS;
		}

		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtWriteFile(const syscall_context& c, const uint64_t file_handle, const uint64_t /*event*/,
	                            const uint64_t /*apc_routine*/,
	                            const uint64_t /*apc_context*/,
	                            const emulator_object<IO_STATUS_BLOCK> /*io_status_block*/,
	                            uint64_t buffer, const ULONG length,
	                            const emulator_object<LARGE_INTEGER> /*byte_offset*/,
	                            const emulator_object<ULONG> /*key*/)
	{
		if (file_handle == STDOUT_HANDLE)
		{
			std::string temp_buffer{};
			temp_buffer.resize(length);
			c.emu.read_memory(buffer, temp_buffer.data(), temp_buffer.size());

			(void)fwrite(temp_buffer.data(), 1, temp_buffer.size(), stdout);
			(void)fflush(stdout);

			return STATUS_SUCCESS;
		}

		puts("NtWriteFile not supported");
		c.emu.stop();
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtCreateFile(const syscall_context& c, const emulator_object<uint64_t> file_handle,
	                             ACCESS_MASK /*desired_access*/,
	                             const emulator_object<OBJECT_ATTRIBUTES> object_attributes)
	{
		const auto attributes = object_attributes.read();
		const auto filename = read_unicode_string(c.emu, attributes.ObjectName);

		if (filename == L"\\Device\\ConDrv\\Server")
		{
			file_handle.write(CONSOLE_SERVER.bits);
			return STATUS_SUCCESS;
		}

		handle root_handle{};
		root_handle.bits = reinterpret_cast<uint64_t>(attributes.RootDirectory);
		if (root_handle.value.is_pseudo && (filename == L"\\Reference" || filename == L"\\Connect"))
		{
			file_handle.write(root_handle.bits);
			return STATUS_SUCCESS;
		}

		printf("Unsupported file: %S\n", filename.c_str());
		return STATUS_NOT_SUPPORTED;
	}

	NTSTATUS handle_NtRaiseHardError(const syscall_context& c, const NTSTATUS error_status,
	                                 const ULONG /*number_of_parameters*/,
	                                 const emulator_object<UNICODE_STRING> /*unicode_string_parameter_mask*/,
	                                 const emulator_object<DWORD> /*parameters*/,
	                                 const HARDERROR_RESPONSE_OPTION /*valid_response_option*/,
	                                 const emulator_object<HARDERROR_RESPONSE> response)
	{
		if (response)
		{
			response.write(ResponseAbort);
		}

		printf("Hard error: %X\n", static_cast<uint32_t>(error_status));
		c.emu.stop();
		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtCreateSemaphore(const syscall_context& c, const emulator_object<uint64_t> semaphore_handle,
	                                  const ACCESS_MASK /*desired_access*/,
	                                  const emulator_object<OBJECT_ATTRIBUTES> object_attributes,
	                                  const ULONG initial_count, const ULONG maximum_count)
	{
		semaphore s{};
		s.current_count = initial_count;
		s.max_count = maximum_count;

		if (object_attributes)
		{
			const auto attributes = object_attributes.read();
			if (attributes.ObjectName)
			{
				s.name = read_unicode_string(c.emu, attributes.ObjectName);
			}
		}

		const auto handle = c.proc.semaphores.store(std::move(s));
		semaphore_handle.write(handle.bits);

		return STATUS_SUCCESS;
	}

	NTSTATUS handle_NtAddAtomEx(const syscall_context& c, const uint64_t atom_name, const ULONG length,
	                            const emulator_object<RTL_ATOM> atom, const ULONG /*flags*/)
	{
		std::wstring name{};
		name.resize(length / 2);

		c.emu.read_memory(atom_name, name.data(), length);

		uint16_t index = 0;
		if (!c.proc.atoms.empty())
		{
			auto i = c.proc.atoms.end();
			--i;
			index = i->first + 1;
		}

		std::optional<uint16_t> last_entry{};
		for (auto& entry : c.proc.atoms)
		{
			if (entry.second == name)
			{
				if (atom)
				{
					atom.write(entry.first);
					return STATUS_SUCCESS;
				}
			}

			if (entry.first > 0)
			{
				if (!last_entry)
				{
					index = 0;
				}
				else
				{
					const auto diff = entry.first - *last_entry;
					if (diff > 1)
					{
						index = *last_entry + 1;
					}
				}
			}

			last_entry = entry.first;
		}

		c.proc.atoms[index] = std::move(name);
		atom.write(index);
		return STATUS_SUCCESS;
	}
}

syscall_dispatcher::syscall_dispatcher(const exported_symbols& ntdll_exports, const exported_symbols& win32u_exports)
{
	const auto ntdll_syscalls = find_syscalls(ntdll_exports);
	const auto win32u_syscalls = find_syscalls(win32u_exports);

#define add_handler(syscall) do                                                \
	{                                                                          \
		std::string name = #syscall;                                           \
		const auto id = get_syscall_id(ntdll_syscalls, win32u_syscalls, name); \
		auto handler = +[](const syscall_context& c)                           \
		{                                                                      \
			forward(c, handle_ ## syscall);                                    \
		};                                                                     \
		                                                                       \
		syscall_handler_entry entry{};                                         \
		entry.handler = handler;                                               \
		entry.name = std::move(name);                                          \
		this->handlers_[id] = std::move(entry);                                \
	} while(0)

	add_handler(NtSetInformationThread);
	add_handler(NtSetEvent);
	add_handler(NtClose);
	add_handler(NtOpenKey);
	add_handler(NtAllocateVirtualMemory);
	add_handler(NtQueryInformationProcess);
	add_handler(NtSetInformationProcess);
	add_handler(NtFreeVirtualMemory);
	add_handler(NtQueryVirtualMemory);
	add_handler(NtOpenThreadToken);
	add_handler(NtQueryPerformanceCounter);
	add_handler(NtQuerySystemInformation);
	add_handler(NtCreateEvent);
	add_handler(NtProtectVirtualMemory);
	add_handler(NtOpenDirectoryObject);
	add_handler(NtTraceEvent);
	add_handler(NtAllocateVirtualMemoryEx);
	add_handler(NtCreateIoCompletion);
	add_handler(NtCreateWaitCompletionPacket);
	add_handler(NtCreateWorkerFactory);
	add_handler(NtManageHotPatch);
	add_handler(NtOpenSection);
	add_handler(NtMapViewOfSection);
	add_handler(NtOpenSymbolicLinkObject);
	add_handler(NtQuerySymbolicLinkObject);
	add_handler(NtQuerySystemInformationEx);
	add_handler(NtOpenFile);
	add_handler(NtQueryVolumeInformationFile);
	add_handler(NtApphelpCacheControl);
	add_handler(NtCreateSection);
	add_handler(NtConnectPort);
	add_handler(NtCreateFile);
	add_handler(NtDeviceIoControlFile);
	add_handler(NtQueryWnfStateData);
	add_handler(NtOpenProcessToken);
	add_handler(NtQuerySecurityAttributesToken);
	add_handler(NtQueryLicenseValue);
	add_handler(NtTestAlert);
	add_handler(NtContinue);
	add_handler(NtTerminateProcess);
	add_handler(NtWriteFile);
	add_handler(NtRaiseHardError);
	add_handler(NtCreateSemaphore);
	add_handler(NtReadVirtualMemory);
	add_handler(NtQueryInformationToken);
	add_handler(NtDxgkIsFeatureEnabled);
	add_handler(NtAddAtomEx);

#undef add_handler
}

void syscall_dispatcher::dispatch(x64_emulator& emu, process_context& context)
{
	const auto address = emu.read_instruction_pointer();
	const auto syscall_id = emu.reg<uint32_t>(x64_register::eax);


	const syscall_context c{emu, context, true};

	try
	{
		const auto entry = this->handlers_.find(syscall_id);
		if (entry == this->handlers_.end())
		{
			printf("Unhandled syscall: %X\n", syscall_id);
			c.emu.reg<uint64_t>(x64_register::rax, STATUS_NOT_SUPPORTED);
			c.emu.stop();
		}
		else
		{
			printf("Handling syscall: %s with id %X at %llX \n", entry->second.name.c_str(), syscall_id, address);
			entry->second.handler(c);
		}
	}
	catch (std::exception& e)
	{
		printf("Syscall threw an exception: %X (%llX) - %s\n", syscall_id, address, e.what());
		emu.reg<uint64_t>(x64_register::rax, STATUS_UNSUCCESSFUL);
		emu.stop();
	}
	catch (...)
	{
		printf("Syscall threw an unknown exception: %X (%llX)\n", syscall_id, address);
		emu.reg<uint64_t>(x64_register::rax, STATUS_UNSUCCESSFUL);
		emu.stop();
	}
}