ARMSX2/pcsx2/PINE.cpp

// SPDX-FileCopyrightText: 2002-2026 PCSX2 Dev Team
// SPDX-License-Identifier: GPL-3.0+

#include "BuildVersion.h"
#include "Common.h"
#include "Host.h"
#include "Elfheader.h"
#include "GS.h"
#include "GS/GSPerfMon.h"
#include "GS/Renderers/Common/GSDevice.h"
#include "MTGS.h"
#include "PerformanceMetrics.h"
#include "SaveState.h"
#include "PINE.h"
#include "VMManager.h"
#include "vtlb.h"
#include "common/Error.h"
#include "common/SettingsInterface.h"
#include "common/Threading.h"

#include <atomic>
#include <cstdio>
#include <cstdlib>
#include <span>
#include <sys/types.h>
#include <thread>

#include "fmt/format.h"

#if defined(_WIN32)
#define read_portable(a, b, c) (recv(a, (char*)b, c, 0))
#define write_portable(a, b, c) (send(a, (const char*)b, c, 0))
#define safe_close_portable(a) \
	do \
	{ \
		if ((a) >= 0) \
		{ \
			closesocket((a)); \
			(a) = INVALID_SOCKET; \
		} \
	} while (0)
#include "common/RedtapeWindows.h"
#include <WinSock2.h>
#elif defined(__linux__) || defined(__FreeBSD__)
#define read_portable(a, b, c) (read(a, b, c))
#define write_portable(a, b, c) (send(a, b, c, MSG_NOSIGNAL))
#define safe_close_portable(a) \
	do \
	{ \
		if ((a) >= 0) \
		{ \
			close((a)); \
			(a) = -1; \
		} \
	} while (0)
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#else
#define read_portable(a, b, c) (read(a, b, c))
#define write_portable(a, b, c) (write(a, b, c))
#define safe_close_portable(a) \
	do \
	{ \
		if ((a) >= 0) \
		{ \
			close((a)); \
			(a) = -1; \
		} \
	} while (0)
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#endif

#define PINE_EMULATOR_NAME "pcsx2"

#ifdef _WIN32

static bool InitializeWinsock()
{
	static bool initialized = false;
	if (initialized)
		return true;

	WSADATA wsa = {};
	if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
		return false;

	initialized = true;
	std::atexit([]() { WSACleanup(); });
	return true;
}

#endif

namespace PINEServer
{
	static std::thread s_thread;
	static int s_slot;

#ifdef _WIN32
	// windows claim to have support for AF_UNIX sockets but that is a blatant lie,
	// their SDK won't even run their own examples, so we go on TCP sockets.
	static SOCKET s_sock = INVALID_SOCKET;
	// the message socket used in thread's accept().
	static SOCKET s_msgsock = INVALID_SOCKET;
#else
	// absolute path of the socket. Stored in XDG_RUNTIME_DIR, if unset /tmp
	static std::string s_socket_name;
	static int s_sock = -1;
	// the message socket used in thread's accept().
	static int s_msgsock = -1;
#endif

	// Whether the socket processing thread should stop executing/is stopped.
	static std::atomic_bool s_end{true};

	/**
	 * Maximum memory used by an IPC message request.
	 * Equivalent to 50,000 Write64 requests.
	 */
#define MAX_IPC_SIZE 650000

	/**
	 * Maximum memory used by an IPC message reply.
	 * Equivalent to 50,000 Read64 replies.
	 */
#define MAX_IPC_RETURN_SIZE 450000

	/**
	 * IPC return buffer.
	 * A preallocated buffer used to store all IPC replies.
	 * to the size of 50.000 MsgWrite64 IPC calls.
	 */
	static std::vector<u8> s_ret_buffer;

	/**
	 * IPC messages buffer.
	 * A preallocated buffer used to store all IPC messages.
	 */
	static std::vector<u8> s_ipc_buffer;

	/**
	 * IPC Command messages opcodes.
	 * A list of possible operations possible by the IPC.
	 * Each one of them is what we call an "opcode" and is the first
	 * byte sent by the IPC to differentiate between commands.
	 */
	enum IPCCommand : unsigned char
	{
		MsgRead8 = 0, /**< Read 8 bit value to memory. */
		MsgRead16 = 1, /**< Read 16 bit value to memory. */
		MsgRead32 = 2, /**< Read 32 bit value to memory. */
		MsgRead64 = 3, /**< Read 64 bit value to memory. */
		MsgWrite8 = 4, /**< Write 8 bit value to memory. */
		MsgWrite16 = 5, /**< Write 16 bit value to memory. */
		MsgWrite32 = 6, /**< Write 32 bit value to memory. */
		MsgWrite64 = 7, /**< Write 64 bit value to memory. */
		MsgVersion = 8, /**< Returns ARMSX2 version. */
		MsgSaveState = 9, /**< Saves a savestate. */
		MsgLoadState = 0xA, /**< Loads a savestate. */
		MsgTitle = 0xB, /**< Returns the game title. */
		MsgID = 0xC, /**< Returns the game ID. */
		MsgUUID = 0xD, /**< Returns the game UUID. */
		MsgGameVersion = 0xE, /**< Returns the game verion. */
		MsgStatus = 0xF, /**< Returns the emulator status. */

		// ARMSX2-local extensions. Upstream PINE stops at 0xF; these are private to
		// this fork, so a generic PINE client will simply never send them.
		MsgGetStats = 0x10, /**< Returns host-side performance statistics as JSON. */
		MsgGetSetting = 0x11, /**< Reads a setting by section/key. */
		MsgSetSetting = 0x12, /**< Writes a setting by section/key and applies it. */
		MsgFrameAdvance = 0x13, /**< Advances a paused VM by one frame. */
		MsgGSDump = 0x14, /**< Records a GS dump of the next N frames. */

		MsgUnimplemented = 0xFF /**< Unimplemented IPC message. */
	};

	/**
	 * Emulator status enum.
	 * A list of possible emulator statuses.
	 */
	enum EmuStatus : uint32_t
	{
		Running = 0, /**< Game is running */
		Paused = 1, /**< Game is paused */
		Shutdown = 2 /**< Game is shutdown */
	};

	/**
	 * IPC message buffer.
	 * A list of all needed fields to store an IPC message.
	 */
	struct IPCBuffer
	{
		int size; /**< Size of the buffer. */
		std::vector<u8> buffer; /**< Buffer. */
	};

	/**
	 * IPC result codes.
	 * A list of possible result codes the IPC can send back.
	 * Each one of them is what we call an "opcode" or "tag" and is the
	 * first byte sent by the IPC to differentiate between results.
	 */
	enum IPCResult : unsigned char
	{
		IPC_OK = 0, /**< IPC command successfully completed. */
		IPC_FAIL = 0xFF /**< IPC command failed to complete. */
	};

	// Thread used to relay IPC commands.
	void MainLoop();
	void ClientLoop();

	/**
	 * Internal function, Parses an IPC command.
	 * buf: buffer containing the IPC command.
	 * buf_size: size of the buffer announced.
	 * ret_buffer: buffer that will be used to send the reply.
	 * return value: IPCBuffer containing a buffer with the result
	 *               of the command and its size.
	 */
	static IPCBuffer ParseCommand(std::span<u8> buf, std::vector<u8>& ret_buffer, u32 buf_size);

	/**
	 * Formats an IPC buffer
	 * ret_buffer: return buffer to use.
	 * size: size of the IPC buffer.
	 * return value: buffer containing the status code allocated of size
	 */
	static std::vector<u8>& MakeOkIPC(std::vector<u8>& ret_buffer, uint32_t size);
	static std::vector<u8>& MakeFailIPC(std::vector<u8>& ret_buffer, uint32_t size);

	/**
	 * Initializes an open socket for IPC communication.
	 */
	bool AcceptClient();

	/**
	 * Converts a primitive value to bytes in little endian
	 * res_vector: the vector to modify
	 * res: the value to convert
	 * i: where to insert it into the vector
	 * NB: implicitely inlined
	 */
	template <typename T>
	static void ToResultVector(std::vector<u8>& res_vector, T res, int i)
	{
		memcpy(&res_vector[i], (char*)&res, sizeof(T));
	}

	/**
	 * Converts bytes in little endian to a primitive value
	 * span: the span to convert
	 * i: where to load it from the span
	 * return value: the converted value
	 * NB: implicitely inlined
	 */
	template <typename T>
	static T FromSpan(std::span<u8> span, int i)
	{
		return *(T*)(&span[i]);
	}

	/**
	 * Ensures an IPC message isn't too big.
	 * return value: false if checks failed, true otherwise.
	 */
	static inline bool SafetyChecks(u32 command_len, int command_size, u32 reply_len, int reply_size = 0, u32 buf_size = MAX_IPC_SIZE - 1)
	{
		return !((command_len + command_size) > buf_size ||
				 (reply_len + reply_size) >= MAX_IPC_RETURN_SIZE);
	}

	/**
	 * Reads a length-prefixed ([u32 len][len bytes], no NUL) string argument, advancing
	 * buf_cnt past it. Returns false if the declared length runs off the end of the
	 * request, in which case the caller must fail the command.
	 */
	static bool ReadLengthPrefixedString(std::span<u8> buf, u32& buf_cnt, u32 buf_size, std::string* out)
	{
		if ((buf_cnt + 4) > buf_size)
			return false;

		const u32 len = FromSpan<u32>(buf, buf_cnt);
		buf_cnt += 4;

		// Bound the allocation by what the request could actually contain.
		if (len > buf_size || (buf_cnt + len) > buf_size)
			return false;

		out->assign(reinterpret_cast<const char*>(&buf[buf_cnt]), len);
		buf_cnt += len;
		return true;
	}

	/**
	 * Builds the host-side statistics document. Called on the PINE thread.
	 *
	 * PerformanceMetrics and g_perfmon are plain scalar reads -- racy against the GS
	 * thread but benign, since every field is an independently-meaningful number and a
	 * torn sample only costs one stale stat. GSgetStats/GSgetMemoryStats are NOT safe
	 * here: they dereference g_texture_cache and g_gs_device, which are GS-thread
	 * owned, so the texture-cache memory figures are gathered via RunOnGSThread.
	 */
	static std::string BuildStatsJson()
	{
		SmallString gs_memory;
		// Device identity is the axis nearly every mobile GPU bug turns on, so a stats
		// blob without it is not attributable to a driver. Adreno tiers run drivers
		// (Mesa Turnip vs Qualcomm proprietary) that behave oppositely for fbfetch and
		// push descriptors, so the driver string matters more than the device name.
		std::string device_name, driver_info;
		if (MTGS::IsOpen())
		{
			// The MTGS ring is single-producer: m_WritePos is owned by the EE/CPU
			// thread, so only it may push packets. RunOnGSThread pushes a packet, and
			// WaitGS drains the ring -- calling them from the PINE thread makes a second
			// producer that races the EE thread's own ring writes, desyncing the
			// pending-packet count. That lost-wakeup-deadlocks the EE thread (parked in
			// WaitGS waiting for empty) against the GS thread (asleep in WaitForWork on
			// no work). Marshal onto the CPU thread first -- the legitimate producer --
			// and block until the GS-owned sample has been gathered.
			Host::RunOnCPUThread(
				[&gs_memory, &device_name, &driver_info]() {
					MTGS::RunOnGSThread([&gs_memory, &device_name, &driver_info]() {
						GSgetMemoryStats(gs_memory);
						if (g_gs_device)
						{
							device_name = g_gs_device->GetName();
							driver_info = g_gs_device->GetDriverInfo();
						}
					});
					MTGS::WaitGS(false);
				},
				true);
		}
		// Newlines and quotes would break the JSON; GetDriverInfo() is multi-line on Vulkan.
		const auto sanitize = [](std::string& s) {
			for (char& c : s)
			{
				if (c == '\n' || c == '\r' || c == '\t')
					c = ' ';
				else if (c == '"' || c == '\\')
					c = '\'';
			}
		};
		sanitize(device_name);
		sanitize(driver_info);

		const auto counter = [](GSPerfMon::counter_t c) { return g_perfmon.Get(c); };

		return fmt::format(
			"{{"
			"\"fps\":{:.3f},\"internal_fps\":{:.3f},\"speed\":{:.3f},"
			"\"frame_ms_avg\":{:.3f},\"frame_ms_min\":{:.3f},\"frame_ms_max\":{:.3f},"
			"\"cpu_thread_pct\":{:.3f},\"cpu_thread_ms\":{:.3f},"
			"\"gs_thread_pct\":{:.3f},\"gs_thread_ms\":{:.3f},"
			"\"gs_back_thread_pct\":{:.3f},\"gs_back_thread_ms\":{:.3f},"
			"\"vu_thread_pct\":{:.3f},\"vu_thread_ms\":{:.3f},"
			"\"gpu_pct\":{:.3f},\"gpu_ms_avg\":{:.3f},\"gpu_ms_last\":{:.3f},"
			"\"gpu_vs_invocations\":{:.0f},\"gpu_ps_invocations\":{:.0f},"
			"\"prims\":{:.1f},\"draws\":{:.1f},\"draw_calls\":{:.1f},"
			"\"render_passes\":{:.1f},\"barriers\":{:.1f},\"readbacks\":{:.1f},"
			"\"texture_copies\":{:.1f},\"texture_uploads\":{:.1f},"
			"\"draw_calls_rov\":{:.1f},\"barriers_rov\":{:.1f},\"texture_copies_rov\":{:.1f},"
			"\"tc_source_hit\":{:.1f},\"tc_source_miss\":{:.1f},"
			"\"tc_target_hit\":{:.1f},\"tc_target_miss\":{:.1f},"
			"\"hash_cache_hit\":{:.1f},\"hash_cache_miss\":{:.1f},"
			"\"gs_memory\":\"{}\",\"frame_number\":{},\"gs_front_parser\":{},"
			"\"renderer\":\"{}\",\"device_name\":\"{}\",\"driver_info\":\"{}\""
			"}}",
			PerformanceMetrics::GetFPS(), PerformanceMetrics::GetInternalFPS(), PerformanceMetrics::GetSpeed(),
			PerformanceMetrics::GetAverageFrameTime(), PerformanceMetrics::GetMinimumFrameTime(),
			PerformanceMetrics::GetMaximumFrameTime(),
			PerformanceMetrics::GetCPUThreadUsage(), PerformanceMetrics::GetCPUThreadAverageTime(),
			PerformanceMetrics::GetGSThreadUsage(), PerformanceMetrics::GetGSThreadAverageTime(),
			// Zero unless GSBackThreadMode >= Lockstep. gs_thread_* is the MTGS thread only,
			// so under the split the two have to be read together to see the GS cost.
			PerformanceMetrics::GetGSBackThreadUsage(), PerformanceMetrics::GetGSBackThreadAverageTime(),
			PerformanceMetrics::GetVUThreadUsage(), PerformanceMetrics::GetVUThreadAverageTime(),
			PerformanceMetrics::GetGPUUsage(), PerformanceMetrics::GetGPUAverageTime(),
			PerformanceMetrics::GetLastGPUTime(),
			PerformanceMetrics::GetGPUAverageVSInvocations(), PerformanceMetrics::GetGPUAveragePSInvocations(),
			counter(GSPerfMon::Prim), counter(GSPerfMon::Draw), counter(GSPerfMon::DrawCalls),
			counter(GSPerfMon::RenderPasses), counter(GSPerfMon::Barriers), counter(GSPerfMon::Readbacks),
			counter(GSPerfMon::TextureCopies), counter(GSPerfMon::TextureUploads),
			counter(GSPerfMon::DrawCallsROV), counter(GSPerfMon::BarriersROV), counter(GSPerfMon::TextureCopiesROV),
			counter(GSPerfMon::TCSourceHit), counter(GSPerfMon::TCSourceMiss),
			counter(GSPerfMon::TCTargetHit), counter(GSPerfMon::TCTargetMiss),
			counter(GSPerfMon::HashCacheHit), counter(GSPerfMon::HashCacheMiss),
			// Whether the two-object split actually engaged, which the BackThreadMode setting
			// alone does not tell you -- it downgrades to lockstep on an unsupported config.
			// True is also what makes gs_back_thread_* worth reading next to gs_thread_*.
			gs_memory.view(), PerformanceMetrics::GetFrameNumber(), GSHasFrontParser() ? "true" : "false",
			Pcsx2Config::GSOptions::GetRendererName(EmuConfig.GS.Renderer), device_name, driver_info);
	}

	/**
	 * Escapes a string for embedding in a JSON string literal. Only paths go through this
	 * -- a Windows path is full of backslashes, which would otherwise leave the reply
	 * unparseable. BuildStatsJson's sanitizer is a different job: it flattens driver blurb
	 * that is allowed to lose fidelity, whereas a path the client is about to open is not.
	 */
	static std::string JsonEscape(const std::string_view str)
	{
		std::string out;
		out.reserve(str.size());
		for (const char c : str)
		{
			if (c == '"' || c == '\\')
				out.push_back('\\');
			out.push_back(c);
		}
		return out;
	}

	/**
	 * Queues a GS dump of the next `frames` frames, or stops a dump already recording when
	 * `frames` is zero -- the same pair of actions the GSDumpMultiFrame hotkey binds to press
	 * and release. `path` may be empty for the usual auto-named file under the snapshots
	 * folder. Returns false only if there is no GS to dump, which fails the command.
	 *
	 * Marshalled the same way as BuildStatsJson and for the same reason: the MTGS ring is
	 * single-producer and the PINE thread is not that producer, so pushing a packet from
	 * here races the EE thread's own writes and can deadlock the two of them. Hop to the CPU
	 * thread, push from there, and block until the GS thread has taken the request.
	 *
	 * The reply describes the request, not a finished file. The dump is opened on the next
	 * VSync and a multi-frame dump is closed some frames after that, so a client that waits
	 * for the file has to keep the VM running or step it with MsgFrameAdvance -- a paused VM
	 * never reaches the VSync that writes anything. A screenshot lands next to the dump too;
	 * that is inherent to the snapshot path, not something this command adds.
	 *
	 * `queued` false carries a `reason`, because both ways a request can be turned away are
	 * served commands that quietly did nothing rather than socket-level failures. The reasons
	 * are not symmetric: "snapshot pending" is a request that arrived between another one and
	 * the VSync servicing it, and retrying a frame later works. "already recording" is a
	 * refusal -- the snapshot path creates a dump only when none exists, so a second request
	 * would take a screenshot, write no dump, and overwrite the frame counter of the dump
	 * already running, cutting it short. Handing back a path for a file that will never appear
	 * is the worst of the available answers, so stop the running dump first if you mean to.
	 */
	static bool QueueGSDump(u32 frames, std::string path, std::string* reply)
	{
		if (!MTGS::IsOpen())
			return false;

		// QueueSnapshot honours a caller-supplied path only when it ends in .png, which it
		// strips to get the base name shared by the screenshot and the dump; anything else is
		// silently discarded in favour of an auto-named file in the snapshots folder. Silence
		// is the wrong failure for a scripted client -- it writes somewhere the script never
		// looks -- so meet that contract here instead. Drop a dump or image suffix if the
		// caller spelled one out, so naming the file you want does not earn you a doubled
		// extension, and let what is left be the base name.
		if (!path.empty())
		{
			for (const std::string_view suffix : {".gs.zst", ".gs.xz", ".gs", ".png"})
			{
				if (StringUtil::EndsWithNoCase(path, suffix))
				{
					path.erase(path.size() - suffix.size());
					break;
				}
			}
		}

		bool queued = false, stopped = false;
		std::string base;
		const char* dump_ext = "";
		const char* reason = "";

		Host::RunOnCPUThread(
			[&]() {
				MTGS::RunOnGSThread([&]() {
					if (frames == 0)
					{
						GSStopGSDump();
						stopped = true;
						return;
					}

					if (GSIsDumpRecording())
					{
						reason = "already recording";
						return;
					}

					// Resolve the auto-name here rather than leaving it to QueueSnapshot, so the
					// reply can name the exact file the client is about to wait for.
					base = path.empty() ? GSGetBaseSnapshotFilename() : path;
					queued = GSQueueSnapshot(base + ".png", frames);
					if (!queued)
					{
						reason = "snapshot pending";
						return;
					}

					// GSConfig is the GS thread's copy of the config, so read the compression
					// method here -- it decides the extension the dump writer will append.
					switch (GSConfig.GSDumpCompression)
					{
						case GSDumpCompressionMethod::Uncompressed:
							dump_ext = ".gs";
							break;
						case GSDumpCompressionMethod::LZMA:
							dump_ext = ".gs.xz";
							break;
						default:
							dump_ext = ".gs.zst";
							break;
					}
				});
				MTGS::WaitGS(false);
			},
			true);

		*reply = fmt::format(
			"{{\"queued\":{},\"stopped\":{},\"frames\":{},\"path\":\"{}\",\"reason\":\"{}\"}}",
			queued ? "true" : "false", stopped ? "true" : "false", frames,
			queued ? JsonEscape(base + dump_ext) : std::string(), reason);
		return true;
	}
} // namespace PINEServer

bool PINEServer::Initialize(int slot)
{
	s_end.store(false, std::memory_order_release);
	s_slot = slot;

#ifdef _WIN32
	if (!InitializeWinsock())
	{
		Console.WriteLn(Color_Red, "PINE: Cannot initialize winsock! Shutting down...");
		Deinitialize();
		return false;
	}

	s_sock = socket(AF_INET, SOCK_STREAM, 0);
	if ((s_sock == INVALID_SOCKET) || slot > 65536)
	{
		Console.WriteLn(Color_Red, "PINE: Cannot open socket! Shutting down...");
		Deinitialize();
		return false;
	}

	sockaddr_in server = {};
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = htonl(INADDR_LOOPBACK); // localhost only
	server.sin_port = htons(slot);

	if (bind(s_sock, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR)
	{
		Console.WriteLn(Color_Red, "PINE: Error while binding to socket! Shutting down...");
		Deinitialize();
		return false;
	}

#else
	char* runtime_dir = nullptr;
#ifdef __APPLE__
	runtime_dir = std::getenv("TMPDIR");
#else
	runtime_dir = std::getenv("XDG_RUNTIME_DIR");
#endif
	// fallback in case macOS or other OSes don't implement the XDG base
	// spec
	if (runtime_dir == nullptr)
		s_socket_name = "/tmp/" PINE_EMULATOR_NAME ".sock";
	else
	{
		s_socket_name = runtime_dir;
		s_socket_name += "/" PINE_EMULATOR_NAME ".sock";
	}

	if (slot != PINE_DEFAULT_SLOT)
		s_socket_name += "." + std::to_string(slot);

	struct sockaddr_un server;

	s_sock = socket(AF_UNIX, SOCK_STREAM, 0);
	if (s_sock < 0)
	{
		Console.WriteLn(Color_Red, "PINE: Cannot open socket! Shutting down...");
		Deinitialize();
		return false;
	}
	server.sun_family = AF_UNIX;
	StringUtil::Strlcpy(server.sun_path, s_socket_name, sizeof(server.sun_path));

	// we unlink the socket so that when releasing this thread the socket gets
	// freed even if we didn't close correctly the loop
	unlink(s_socket_name.c_str());
	if (bind(s_sock, (struct sockaddr*)&server, sizeof(struct sockaddr_un)))
	{
		Console.WriteLn(Color_Red, "PINE: Error while binding to socket! Shutting down...");
		Deinitialize();
		return false;
	}
#endif

	// maximum queue of 4096 commands before refusing, approximated to the
	// nearest legal value. We do not use SOMAXCONN as windows have this idea
	// that a "reasonable" value is 5, which is not.
	if (listen(s_sock, 4096))
	{
		Console.WriteLn(Color_Red, "PINE: Cannot listen for connections! Shutting down...");
		Deinitialize();
		return false;
	}

	// we allocate once buffers to not have to do mallocs for each IPC
	// request, as malloc is expansive when we optimize for µs.
	s_ret_buffer.resize(MAX_IPC_RETURN_SIZE);
	s_ipc_buffer.resize(MAX_IPC_SIZE);

	// we start the thread
	s_thread = std::thread(&PINEServer::MainLoop);

	return true;
}

bool PINEServer::IsInitialized()
{
	return !s_end.load(std::memory_order_acquire);
}

int PINEServer::GetSlot()
{
	return s_slot;
}

std::vector<u8>& PINEServer::MakeOkIPC(std::vector<u8>& ret_buffer, uint32_t size = 5)
{
	ToResultVector<uint32_t>(ret_buffer, size, 0);
	ret_buffer[4] = IPC_OK;
	return ret_buffer;
}

std::vector<u8>& PINEServer::MakeFailIPC(std::vector<u8>& ret_buffer, uint32_t size = 5)
{
	ToResultVector<uint32_t>(ret_buffer, size, 0);
	ret_buffer[4] = IPC_FAIL;
	return ret_buffer;
}

bool PINEServer::AcceptClient()
{
	s_msgsock = accept(s_sock, 0, 0);
	if (s_msgsock < 0)
	{
		// everything else is non recoverable in our scope
		// we also mark as recoverable socket errors where it would block a
		// non blocking socket, even though our socket is blocking, in case
		// we ever have to implement a non blocking socket.
#ifdef _WIN32
		const int errno_w = WSAGetLastError();
		if (!(errno_w == WSAECONNRESET || errno_w == WSAEINTR || errno_w == WSAEINPROGRESS || errno_w == WSAEMFILE || errno_w == WSAEWOULDBLOCK) && s_sock != INVALID_SOCKET)
			Console.Error("PINE: accept() returned error %d", errno_w);
#else
		if (!(errno == ECONNABORTED || errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) && s_sock >= 0)
			Console.Error("PINE: accept() returned error %d", errno);
#endif

		return false;
	}

#ifdef __APPLE__
	int nosigpipe = 1;
	setsockopt(s_msgsock, SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe, sizeof(nosigpipe));
#endif

	// Gross C-style cast, but SOCKET is a handle on Windows.
	Console.WriteLn("PINE: New client with FD %d connected.", (int)s_msgsock);
	return true;
}

void PINEServer::MainLoop()
{
	Threading::SetNameOfCurrentThread("PINE Server");

	while (!s_end.load(std::memory_order_acquire))
	{
		if (!AcceptClient())
			continue;

		ClientLoop();

		Console.WriteLn("PINE: Client disconnected.");
		safe_close_portable(s_msgsock);
	}
}

void PINEServer::ClientLoop()
{
	while (!s_end.load(std::memory_order_acquire))
	{
		// either int or ssize_t depending on the platform, so we have to
		// use a bunch of auto
		auto receive_length = 0;
		auto end_length = 4;
		const std::span<u8> ipc_buffer_span(s_ipc_buffer);

		// while we haven't received the entire packet, maybe due to
		// socket datagram splittage, we continue to read
		while (receive_length < end_length)
		{
			const auto tmp_length = read_portable(s_msgsock, &ipc_buffer_span[receive_length], MAX_IPC_SIZE - receive_length);

			// we recreate the socket if an error happens
			if (tmp_length <= 0)
				return;

			receive_length += tmp_length;

			// if we got at least the final size then update
			if (end_length == 4 && receive_length >= 4)
			{
				end_length = FromSpan<u32>(ipc_buffer_span, 0);
				// we'd like to avoid a client trying to do OOB
				if (end_length > MAX_IPC_SIZE || end_length < 4)
				{
					receive_length = 0;
					break;
				}
			}
		}
		PINEServer::IPCBuffer res;

		// we remove 4 bytes to get the message size out of the IPC command
		// size in ParseCommand.
		// also, if we got a failed command, let's reset the state so we don't
		// end up deadlocking by getting out of sync, eg when a client
		// disconnects
		if (receive_length != 0)
		{
			res = ParseCommand(ipc_buffer_span.subspan(4), s_ret_buffer, (u32)end_length - 4);

			// if we cannot send back our answer restart the socket
			if (write_portable(s_msgsock, res.buffer.data(), res.size) < 0)
				return;
		}
	}
}

void PINEServer::Deinitialize()
{
	s_end.store(true, std::memory_order_release);

#ifndef _WIN32
	if (!s_socket_name.empty())
	{
		unlink(s_socket_name.c_str());
		s_socket_name = {};
	}
#endif

	// shutdown() is needed, otherwise accept() will still block.
#ifdef _WIN32
	if (s_sock != INVALID_SOCKET)
		shutdown(s_sock, SD_BOTH);
#else
	if (s_sock >= 0)
		shutdown(s_sock, SHUT_RDWR);
#endif

	safe_close_portable(s_sock);
	safe_close_portable(s_msgsock);

	if (s_thread.joinable())
		s_thread.join();
}

PINEServer::IPCBuffer PINEServer::ParseCommand(std::span<u8> buf, std::vector<u8>& ret_buffer, u32 buf_size)
{
	u32 ret_cnt = 5;
	u32 buf_cnt = 0;

	while (buf_cnt < buf_size)
	{
		if (!SafetyChecks(buf_cnt, 1, ret_cnt, 0, buf_size)) [[unlikely]]
			return IPCBuffer{5, MakeFailIPC(ret_buffer)};
		buf_cnt++;
		// example IPC messages: MsgRead/Write
		// refer to the client doc for more info on the format
		//         IPC Message event (1 byte)
		//         |  Memory address (4 byte)
		//         |  |           argument (VLE)
		//         |  |           |
		// format: XX YY YY YY YY ZZ ZZ ZZ ZZ
		//        reply code: 00 = OK, FF = NOT OK
		//        |  return value (VLE)
		//        |  |
		// reply: XX ZZ ZZ ZZ ZZ
		switch ((IPCCommand)buf[buf_cnt - 1])
		{
			case MsgRead8:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4, ret_cnt, 1, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				const u8 res = vtlb_ramRead<mem8_t>(a);
				ToResultVector(ret_buffer, res, ret_cnt);
				ret_cnt += 1;
				buf_cnt += 4;
				break;
			}
			case MsgRead16:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4, ret_cnt, 2, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				const u16 res = vtlb_ramRead<mem16_t>(a);
				ToResultVector(ret_buffer, res, ret_cnt);
				ret_cnt += 2;
				buf_cnt += 4;
				break;
			}
			case MsgRead32:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4, ret_cnt, 4, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				const u32 res = vtlb_ramRead<mem32_t>(a);
				ToResultVector(ret_buffer, res, ret_cnt);
				ret_cnt += 4;
				buf_cnt += 4;
				break;
			}
			case MsgRead64:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4, ret_cnt, 8, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				const u64 res = vtlb_ramRead<mem64_t>(a);
				ToResultVector(ret_buffer, res, ret_cnt);
				ret_cnt += 8;
				buf_cnt += 4;
				break;
			}
			case MsgWrite8:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 1 + 4, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				vtlb_ramWrite<mem8_t>(a, FromSpan<u8>(buf, buf_cnt + 4));
				buf_cnt += 5;
				break;
			}
			case MsgWrite16:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 2 + 4, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				vtlb_ramWrite<mem16_t>(a, FromSpan<u16>(buf, buf_cnt + 4));
				buf_cnt += 6;
				break;
			}
			case MsgWrite32:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4 + 4, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				vtlb_ramWrite<mem32_t>(a, FromSpan<u32>(buf, buf_cnt + 4));
				buf_cnt += 8;
				break;
			}
			case MsgWrite64:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 8 + 4, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				const u32 a = FromSpan<u32>(buf, buf_cnt);
				vtlb_ramWrite<mem64_t>(a, FromSpan<u64>(buf, buf_cnt + 4));
				buf_cnt += 12;
				break;
			}
			case MsgVersion:
			{
				u32 size = strlen(BuildVersion::GitRev) + 8;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				snprintf(reinterpret_cast<char*>(&ret_buffer[ret_cnt]), size, "ARMSX2 %s", BuildVersion::GitRev);
				ret_cnt += size;
				break;
			}
			case MsgSaveState:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 1, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				Host::RunOnCPUThread([slot = FromSpan<u8>(buf, buf_cnt)] {
					VMManager::SaveStateToSlot(slot, true, [slot](const std::string& error) {
						SaveState_ReportSaveErrorOSD(error, slot);
					});
				});
				buf_cnt += 1;
				break;
			}
			case MsgLoadState:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 1, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				Host::RunOnCPUThread([slot = FromSpan<u8>(buf, buf_cnt)] {
					Error state_error;
					if (!VMManager::LoadStateFromSlot(slot, false, &state_error))
						SaveState_ReportLoadErrorOSD(state_error.GetDescription(), slot, false);
				});
				buf_cnt += 1;
				break;
			}
			case MsgTitle:
			{
				if (!VMManager::HasValidVM())
					goto error;
				const std::string gameName = VMManager::GetTitle(false);
				const u32 size = gameName.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], gameName.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgID:
			{
				if (!VMManager::HasValidVM())
					goto error;
				const std::string gameSerial = VMManager::GetDiscSerial();
				const u32 size = gameSerial.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], gameSerial.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgUUID:
			{
				if (!VMManager::HasValidVM())
					goto error;
				const std::string crc = fmt::format("{:08x}", VMManager::GetDiscCRC());
				const u32 size = crc.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], crc.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgGameVersion:
			{
				if (!VMManager::HasValidVM())
					goto error;

				const std::string ElfVersion = VMManager::GetDiscVersion();
				const u32 size = ElfVersion.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], ElfVersion.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgStatus:
			{
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, 4, buf_size)) [[unlikely]]
					goto error;
				EmuStatus status;

				switch (VMManager::GetState())
				{
					case VMState::Running:
						status = EmuStatus::Running;
						break;
					case VMState::Paused:
						status = EmuStatus::Paused;
						break;
					default:
						status = EmuStatus::Shutdown;
						break;
				}

				ToResultVector(ret_buffer, status, ret_cnt);
				ret_cnt += 4;
				break;
			}
			case MsgGetStats:
			{
				const std::string stats = BuildStatsJson();
				const u32 size = stats.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], stats.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgGetSetting:
			{
				std::string section, key;
				if (!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &section) ||
					!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &key)) [[unlikely]]
					goto error;

				std::string value;
				{
					auto lock = Host::GetSettingsLock();
					value = Host::GetSettingsInterface()->GetStringValue(section.c_str(), key.c_str(), "");
				}

				const u32 size = value.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], value.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgSetSetting:
			{
				std::string section, key, value;
				if (!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &section) ||
					!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &key) ||
					!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &value)) [[unlikely]]
					goto error;

				// Whether this change tears down the GS device, so the caller knows
				// whether it just paid for a reopen. Everything outside this set is
				// applied in place by GSUpdateConfig.
				const bool restart_required = Pcsx2Config::GSOptions::IsRestartOption(key.c_str());

				// Write the persisted key rather than poking EmuConfig directly: a direct
				// poke is silently reverted by the next ApplySettings, which re-derives
				// EmuConfig from the INI layer stack.
				Host::SetBaseStringSettingValue(section.c_str(), key.c_str(), value.c_str());
				Host::CommitBaseSettingChanges();
				Host::RunOnCPUThread([]() { VMManager::ApplySettings(); });

				const std::string reply = fmt::format("{{\"restart_required\":{}}}", restart_required ? "true" : "false");
				const u32 size = reply.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], reply.c_str(), size);
				ret_cnt += size;
				break;
			}
			case MsgFrameAdvance:
			{
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;
				Host::RunOnCPUThread([]() { VMManager::FrameAdvance(1); });
				break;
			}
			case MsgGSDump:
			{
				// [u32 frames][u32 path_len][path_len bytes]. frames == 0 stops a dump that is
				// already recording; UINT32_MAX records until something stops it.
				if (!VMManager::HasValidVM())
					goto error;
				if (!SafetyChecks(buf_cnt, 4, ret_cnt, 0, buf_size)) [[unlikely]]
					goto error;

				const u32 frames = FromSpan<u32>(buf, buf_cnt);
				buf_cnt += 4;

				std::string path;
				if (!ReadLengthPrefixedString(buf, buf_cnt, buf_size, &path)) [[unlikely]]
					goto error;

				std::string reply;
				if (!QueueGSDump(frames, std::move(path), &reply)) [[unlikely]]
					goto error;

				const u32 size = reply.size() + 1;
				if (!SafetyChecks(buf_cnt, 0, ret_cnt, size + 4, buf_size)) [[unlikely]]
					goto error;
				ToResultVector(ret_buffer, size, ret_cnt);
				ret_cnt += 4;
				memcpy(&ret_buffer[ret_cnt], reply.c_str(), size);
				ret_cnt += size;
				break;
			}
			default:
			{
			error:
				return IPCBuffer{5, MakeFailIPC(ret_buffer)};
			}
		}
	}
	return IPCBuffer{(int)ret_cnt, MakeOkIPC(ret_buffer, ret_cnt)};
}