qemu: Completely rewrite QMP client from scratch

It sucked. The new one is using Sans I/O principles, so it does not
directly do I/O or talk to a net.Socket directly (instead, QemuVM implements
the layer to do I/O). This means in the future this library could actually
be tested, but for now, I'm not bothering with that.

There's also some other cleanups that were bothering me.

cvmts/src/CollabVMServer.ts

@@ -119,21 +119,22 @@ export default class CollabVMServer {
 		this.VM = vm;
 
 		// hack but whatever (TODO: less rickity)
+		let self = this;
 		if (config.vm.type == 'qemu') {
 			(vm as QemuVM).on('statechange', (newState: VMState) => {
 				if(newState == VMState.Started) {
-					this.logger.Info("started!!");
+					//self.logger.Info("started!!");
 
 					// well aware this sucks but whatever
-					this.VM.GetDisplay().on('resize', (size: Size) => this.OnDisplayResized(size));
+					self.VM.GetDisplay().on('resize', (size: Size) => self.OnDisplayResized(size));
-					this.VM.GetDisplay().on('rect', (rect: Rect) => this.OnDisplayRectangle(rect));
+					self.VM.GetDisplay().on('rect', (rect: Rect) => self.OnDisplayRectangle(rect));
 				}
 
 				if (newState == VMState.Stopped) {
-					this.logger.Info('stopped ?');
+					//self.logger.Info('stopped ?');
 					setTimeout(async () => {
-						this.logger.Info('restarting VM');
+						self.logger.Info('restarting VM');
-						await this.VM.Start();
+						await self.VM.Start();
 					}, kRestartTimeout);
 				}
 			});

package.json

@@ -12,7 +12,7 @@
 		"@parcel/packager-ts": "2.12.0",
 		"@parcel/transformer-sass": "2.12.0",
 		"@parcel/transformer-typescript-types": "2.12.0",
-		"@types/node": "^20.12.5",
+		"@types/node": "^20.14.10",
 		"just-install": "^2.0.1",
 		"parcel": "^2.12.0",
 		"prettier": "^3.2.5",

qemu/package.json

@@ -21,11 +21,9 @@
 	"dependencies": {
 		"@computernewb/nodejs-rfb": "*",
 		"@cvmts/shared": "*",
-		"execa": "^8.0.1",
+		"execa": "^8.0.1"
-		"split": "^1.0.1"
 	},
 	"devDependencies": {
-		"@types/split": "^1.0.5",
 		"parcel": "^2.12.0"
 	}
 }

qemu/src/QemuDisplay.ts

@@ -114,6 +114,10 @@ export class QemuDisplay extends EventEmitter {
 	Disconnect() {
 		this.vncShouldReconnect = false;
 		this.displayVnc.disconnect();
+
+		// bye bye!
+		this.displayVnc.removeAllListeners();
+		this.removeAllListeners();
 	}
 
 	Connected() {

qemu/src/QemuVM.ts

@@ -1,10 +1,11 @@
 import { execa, execaCommand, ExecaChildProcess } from 'execa';
 import { EventEmitter } from 'events';
-import QmpClient from './QmpClient.js';
+import { QmpClient, IQmpClientWriter, QmpEvent } from './QmpClient.js';
 import { QemuDisplay } from './QemuDisplay.js';
 import { unlink } from 'node:fs/promises';
 
 import * as Shared from '@cvmts/shared';
+import { Socket, connect } from 'net';
 
 export enum VMState {
 	Stopped,
@@ -28,10 +29,31 @@ const kVmTmpPathBase = `/tmp`;
 /// the VM is forcefully stopped.
 const kMaxFailCount = 5;
 
+// writer implementation for net.Socket
+class SocketWriter implements IQmpClientWriter {
+	socket;
+	client;
+  
+	constructor(socket: Socket, client: QmpClient) {
+	  this.socket = socket;
+	  this.client = client;
+  
+	  this.socket.on('data', (data) => {
+		this.client.feed(data);
+	  });
+	}
+  
+	writeSome(buffer: Buffer) {
+	  this.socket.write(buffer);
+	}
+  }
+  
+
 export class QemuVM extends EventEmitter {
 	private state = VMState.Stopped;
 
-	private qmpInstance: QmpClient | null = null;
+	private qmpInstance: QmpClient = new QmpClient();
+	private qmpSocket: Socket | null = null;
 	private qmpConnected = false;
 	private qmpFailCount = 0;
 
@@ -49,6 +71,30 @@ export class QemuVM extends EventEmitter {
 		this.logger = new Shared.Logger(`CVMTS.QEMU.QemuVM/${this.definition.id}`);
 
 		this.display = new QemuDisplay(this.GetVncPath());
+
+
+		let self = this;
+
+		// Handle the STOP event sent when using -no-shutdown
+		this.qmpInstance.on(QmpEvent.Stop, async () => {
+			await self.qmpInstance.execute('system_reset');
+		})
+
+		this.qmpInstance.on(QmpEvent.Reset, async () => {
+			await self.qmpInstance.execute('cont');
+		});
+
+		this.qmpInstance.on('connected', async () => {
+			self.VMLog().Info('QMP ready');
+
+			this.display = new QemuDisplay(this.GetVncPath());
+			self.display?.Connect();
+
+			// QMP has been connected so the VM is ready to be considered started
+			self.qmpFailCount = 0;
+			self.qmpConnected = true;
+			self.SetState(VMState.Started);
+		});
 	}
 
 	async Start() {
@@ -110,7 +156,7 @@ export class QemuVM extends EventEmitter {
 	}
 
 	async QmpCommand(command: string, args: any | null): Promise<any> {
-		return await this.qmpInstance?.Execute(command, args);
+		return await this.qmpInstance?.execute(command, args);
 	}
 
 	async MonitorCommand(command: string) {
@@ -191,7 +237,6 @@ export class QemuVM extends EventEmitter {
 		this.qemuProcess.on('exit', async (code) => {
 			self.VMLog().Info("QEMU process exited");
 
-
 			// this should be being done anways but it's very clearly not sometimes so
 			// fuck it, let's just force it here
 			try {
@@ -209,7 +254,6 @@ export class QemuVM extends EventEmitter {
 
 			await self.DisconnectDisplay();
 
-
 			if (self.state != VMState.Stopping) {
 				if (code == 0) {
 					// Wait a bit and restart QEMU.
@@ -237,62 +281,43 @@ export class QemuVM extends EventEmitter {
 		let self = this;
 
 		if (!this.qmpConnected) {
-			self.qmpInstance = new QmpClient();
-
-			let onQmpError = async () => {
-				if(self.qmpConnected) {
-					self.qmpConnected = false;
-
-					// If we aren't stopping, then we should care QMP disconnected
-					if (self.state != VMState.Stopping) {
-						if (self.qmpFailCount++ < kMaxFailCount) {
-							self.VMLog().Error(`Failed to connect to QMP ${self.qmpFailCount} times.`);
-							await Shared.Sleep(500);
-							await self.ConnectQmp();
-						} else {
-							self.VMLog().Error(`Reached max retries, giving up.`);
-							await self.Stop();
-						}
-					}
-				}
-			};
-
-			self.qmpInstance.on('close', onQmpError);
-			self.qmpInstance.on('error', (e: Error) => {
-				self.VMLog().Error("QMP Error: {0}", e.message);
-				onQmpError();
-			});
-
-			self.qmpInstance.on('event', async (ev) => {
-				switch (ev.event) {
-					// Handle the STOP event sent when using -no-shutdown
-					case 'STOP':
-						await self.qmpInstance?.Execute('system_reset');
-						break;
-					case 'RESET':
-						await self.qmpInstance?.Execute('cont');
-						break;
-				}
-			});
-
-			self.qmpInstance.on('qmp-ready', async (hadError) => {
-				self.VMLog().Info('QMP ready');
-
-				self.display?.Connect();
-
-				// QMP has been connected so the VM is ready to be considered started
-				self.qmpFailCount = 0;
-				self.qmpConnected = true;
-				self.SetState(VMState.Started);
-			});
-
 			try {
 				await Shared.Sleep(500);
-				this.qmpInstance?.ConnectUNIX(this.GetQmpPath());
+				this.qmpSocket = connect(this.GetQmpPath());
+
+				let onQmpClose = async () => {
+					if(self.qmpConnected) {
+						self.qmpConnected = false;
+						self.qmpSocket = null;
+	
+						// If we aren't stopping, then we should care QMP disconnected
+						if (self.state != VMState.Stopping) {
+							if (self.qmpFailCount++ < kMaxFailCount) {
+								self.VMLog().Error(`Failed to connect to QMP ${self.qmpFailCount} times.`);
+								await Shared.Sleep(500);
+								await self.ConnectQmp();
+							} else {
+								self.VMLog().Error(`Reached max retries, giving up.`);
+								await self.Stop();
+							}
+						}
+					}
+				};
+	
+				this.qmpSocket.on('close', onQmpClose);
+
+				this.qmpSocket.on('error', (e: Error) => {
+					self.VMLog().Error("QMP Error: {0}", e.message);
+				});
+
+				// Setup the QMP client.
+				let writer = new SocketWriter(this.qmpSocket, this.qmpInstance);
+				this.qmpInstance.reset();
+				this.qmpInstance.setWriter(writer);
 			} catch (err) {
 				// just try again
-				await Shared.Sleep(500);
+				//await Shared.Sleep(500);
-				await this.ConnectQmp();
+				//await this.ConnectQmp();
 			}
 		}
 	}
@@ -300,9 +325,7 @@ export class QemuVM extends EventEmitter {
 	private async DisconnectDisplay() {
 		try {
 			this.display?.Disconnect();
-
+			this.display = null;
-			// create a new display (and gc the old one)
-			this.display = new QemuDisplay(this.GetVncPath());
 		} catch (err) {
 			// oh well lol
 		}
@@ -310,11 +333,11 @@ export class QemuVM extends EventEmitter {
 
 	private async DisconnectQmp() {
 		if (this.qmpConnected) return;
-		if (this.qmpInstance == null) return;
+		if (this.qmpSocket == null) return;
 
 		this.qmpConnected = false;
-		this.qmpInstance.end();
+		this.qmpSocket?.end();
-		this.qmpInstance = null;
+
 		try {
 			await unlink(this.GetQmpPath());
 		} catch (err) {}

qemu/src/QmpClient.ts

@@ -1,130 +1,139 @@
-// This was originally based off the contents of the node-qemu-qmp package,
+import { EventEmitter } from "node:events";
-// but I've modified it possibly to the point where it could be treated as my own creation.
 
-import split from 'split';
+enum QmpClientState {
+    Handshaking,
+    Connected
+}
 
-import { Socket } from 'net';
+function qmpStringify(obj: any) {
+    return JSON.stringify(obj) + '\r\n';
+}
 
-export type QmpCallback = (err: Error | null, res: any | null) => void;
+// this writer interface is used to poll back to a higher level
+// I/O layer that we want to write some data.
+export interface IQmpClientWriter {
+    writeSome(data: Buffer) : void;
+}
 
-type QmpCommandEntry = {
+export type QmpClientCallback = (err: Error | null, res: any | null) => void;
-	callback: QmpCallback | null;
+
-	id: number;
+type QmpClientCallbackEntry = {
+    id: number,
+    callback: QmpClientCallback | null
 };
 
-// TODO: Instead of the client "Is-A"ing a Socket, this should instead contain/store a Socket,
+export enum QmpEvent {
-// (preferrably) passed by the user, to use for QMP communications.
+    BlockIOError = 'BLOCK_IO_ERROR',
-// The client shouldn't have to know or care about the protocol, and it effectively hackily uses the fact
+    Reset = 'RESET',
-// Socket extends EventEmitter.
+    Resume = 'RESUME',
+    RtcChange = 'RTC_CHANGE',
+    Shutdown = 'SHUTDOWN',
+    Stop = 'STOP',
+    VncConnected = 'VNC_CONNECTED',
+    VncDisconnected = 'VNC_DISCONNECTED',
+    VncInitalized = 'VNC_INITALIZED',
+    Watchdog = 'WATCHDOG'
+};
 
-export default class QmpClient extends Socket {
-	public qmpHandshakeData: any;
-	private commandEntries: QmpCommandEntry[] = [];
-	private lastID = 0;
 
-	constructor() {
+// A QMP client
-		super();
+export class QmpClient extends EventEmitter {
+    private state = QmpClientState.Handshaking;
+    private capabilities = "";
+    private writer: IQmpClientWriter | null = null;
 
-		this.assignHandlers();
+    private lastID = 0;
-	}
+    private callbacks = new Array<QmpClientCallbackEntry>();
 
-	private ExecuteSync(command: string, args: any | null, callback: QmpCallback | null) {
+    constructor() {
-		let cmd: QmpCommandEntry = {
+        super();
-			callback: callback,
+    }
-			id: ++this.lastID
-		};
 
-		let qmpOut: any = {
+    setWriter(writer: IQmpClientWriter) {
-			execute: command,
+        this.writer = writer;
-			id: cmd.id
+    }
-		};
 
-		if (args) qmpOut['arguments'] = args;
+    feed(data: Buffer) : void {
+        let str = data.toString();
 
-		// Add stuff
+   /* I don't think this is needed but if it is i'm keeping this for now
-		this.commandEntries.push(cmd);
+        if(!str.endsWith('\r\n')) {
-		this.write(JSON.stringify(qmpOut));
+            console.log("incomplete message!");
-	}
+            return;
+        }
+    */
 
-	// TODO: Make this function a bit more ergonomic?
+        let obj = JSON.parse(str);
-	async Execute(command: string, args: any | null = null): Promise<any> {
-		return new Promise((res, rej) => {
-			this.ExecuteSync(command, args, (err, result) => {
-				if (err) rej(err);
-				res(result);
-			});
-		});
-	}
 
-	private Handshake(callback: () => void) {
+        switch(this.state) {
-		this.write(
+            case QmpClientState.Handshaking:
-			JSON.stringify({
+                if(obj["return"] != undefined) {
-				execute: 'qmp_capabilities'
+                    this.state = QmpClientState.Connected;
-			})
+                    this.emit('connected');
-		);
+                    return;
+                }
 
-		this.once('data', (data) => {
+                let capabilities = qmpStringify({
-			// Once QEMU replies to us, the handshake is done.
+                    execute: "qmp_capabilities"
-			// We do not negotiate anything special.
+                });
-			callback();
-		});
-	}
 
-	// this can probably be made async
+                this.writer?.writeSome(Buffer.from(capabilities, 'utf8'));
-	private assignHandlers() {
+                break;
-		let self = this;
 
-		this.on('connect', () => {
+            case QmpClientState.Connected:
-			// this should be more correct?
+                if(obj["return"] != undefined || obj['error'] != undefined) {
-			this.once('data', (data) => {
+                    if(obj['id'] == null)
-				// Handshake QMP with the server.
+                        return;
-				self.qmpHandshakeData = JSON.parse(data.toString('utf8')).QMP;
-				self.Handshake(() => {
-					// Now ready to parse QMP responses/events.
-					self.pipe(split(JSON.parse))
-						.on('data', (json: any) => {
-							if (json == null) return self.end();
 
-							if (json.return || json.error) {
+                    let cb = this.callbacks.find((v) => v.id == obj['id']);
-								// Our handshake has a spurious return because we never assign it an ID,
+                    if(cb == undefined)
-								// and it is gathered by this pipe for some reason I'm not quite sure about.
+                        return;
-								// So, just for safety's sake, don't process any return objects which don't have an ID attached to them.
-								if (json.id == null) return;
 
-								let callbackEntry = this.commandEntries.find((entry) => entry.id === json.id);
+                    let error: Error | null = obj.error ? new Error(obj.error.desc) : null;
-								let error: Error | null = json.error ? new Error(json.error.desc) : null;
 
-								// we somehow didn't find a callback entry for this response.
+                    if(cb.callback)
-								// I don't know how. Techinically not an error..., but I guess you're not getting a reponse to whatever causes this to happen
+                        cb.callback(error, obj.return);
-								if (callbackEntry == null) return;
 
-								if (callbackEntry?.callback) callbackEntry.callback(error, json.return);
+                    this.callbacks.slice(this.callbacks.indexOf(cb));
+                } else if (obj['event']) {
+                    this.emit(obj.event, {
+                        timestamp: obj.timestamp,
+                        data: obj.data
+                    });
+                }
+                break;
+        }
+    }
 
-								// Remove the completed callback entry.
+    executeSync(command: string, args: any | undefined, callback: QmpClientCallback | null) {
-								this.commandEntries.slice(this.commandEntries.indexOf(callbackEntry));
+        let entry = {
-							} else if (json.event) {
+            callback: callback,
-								this.emit('event', json);
+            id: ++this.lastID
-							}
+        };
-						})
-						.on('error', () => {
-							// Give up.
-							return self.end();
-						});
-					this.emit('qmp-ready');
-				});
-			});
-		});
 
-		this.on('close', () => {
+        let qmpOut: any = {
-			this.end();
+            execute: command,
-		});
+            id: entry.id
-	}
+        };
 
-	Connect(host: string, port: number) {
+        if(args !== undefined)
-		super.connect(port, host);
+                qmpOut['arguments'] = args;
-	}
 
-	ConnectUNIX(path: string) {
+        this.callbacks.push(entry);
-		super.connect(path);
+        this.writer?.writeSome(Buffer.from(qmpStringify(qmpOut), 'utf8'));
-	}
+    }
+
+    async execute(command: string, args: any | undefined = undefined) : Promise<any> {
+        return new Promise((res, rej) => {
+            this.executeSync(command, args, (err, result) => {
+                if(err)
+                    rej(err);
+                res(result);
+            });
+        });
+    }
+
+    reset() {
+        this.state = QmpClientState.Handshaking;
+    }
 }

qemu/src/index.ts

@@ -1,3 +1,5 @@
+/// <reference types="../node_modules/@types/node">
+
 export * from './QemuDisplay.js';
 export * from './QemuUtil.js';
 export * from './QemuVM.js';

tsconfig.json

@@ -4,6 +4,7 @@
       "target": "ES2022",
       "module": "ES2022",
       "moduleResolution": "Node",
+	  "types": ["node"],
       "allowSyntheticDefaultImports": true,
       "strict": true,
     }

yarn.lock

@@ -92,10 +92,8 @@ __metadata:
   dependencies:
     "@computernewb/nodejs-rfb": "npm:*"
     "@cvmts/shared": "npm:*"
-    "@types/split": "npm:^1.0.5"
     execa: "npm:^8.0.1"
     parcel: "npm:^2.12.0"
-    split: "npm:^1.0.1"
   languageName: unknown
   linkType: soft
 
@@ -1545,22 +1543,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/split@npm:^1.0.5":
+"@types/node@npm:^20.14.10":
-  version: 1.0.5
+  version: 20.14.10
-  resolution: "@types/split@npm:1.0.5"
+  resolution: "@types/node@npm:20.14.10"
   dependencies:
-    "@types/node": "npm:*"
+    undici-types: "npm:~5.26.4"
-    "@types/through": "npm:*"
+  checksum: 10c0/0b06cff14365c2d0085dc16cc8cbea5c40ec09cfc1fea966be9eeecf35562760bfde8f88e86de6edfaf394501236e229d9c1084fad04fb4dec472ae245d8ae69
-  checksum: 10c0/eb187a3b07e5064928e49bffd5c45ad1f1109135fee52344bb7623cdb55e2ebb16bd6ca009a30a0a6e2b262f7ebb7bf18030ff873819e80fafd4cbb51dba1a74
-  languageName: node
-  linkType: hard
-
-"@types/through@npm:*":
-  version: 0.0.33
-  resolution: "@types/through@npm:0.0.33"
-  dependencies:
-    "@types/node": "npm:*"
-  checksum: 10c0/6a8edd7f40cd7e197318e86310a40e568cddd380609dde59b30d5cc6c5f8276ddc698905eac4b3b429eb39f2e8ee326bc20dc6e95a2cdc41c4d3fc9a1ebd4929
   languageName: node
   linkType: hard
 
@@ -1998,7 +1986,7 @@ __metadata:
     "@parcel/packager-ts": "npm:2.12.0"
     "@parcel/transformer-sass": "npm:2.12.0"
     "@parcel/transformer-typescript-types": "npm:2.12.0"
-    "@types/node": "npm:^20.12.5"
+    "@types/node": "npm:^20.14.10"
     just-install: "npm:^2.0.1"
     parcel: "npm:^2.12.0"
     prettier: "npm:^3.2.5"
@@ -3713,15 +3701,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"split@npm:^1.0.1":
-  version: 1.0.1
-  resolution: "split@npm:1.0.1"
-  dependencies:
-    through: "npm:2"
-  checksum: 10c0/7f489e7ed5ff8a2e43295f30a5197ffcb2d6202c9cf99357f9690d645b19c812bccf0be3ff336fea5054cda17ac96b91d67147d95dbfc31fbb5804c61962af85
-  languageName: node
-  linkType: hard
-
 "sprintf-js@npm:^1.1.3":
   version: 1.1.3
   resolution: "sprintf-js@npm:1.1.3"
@@ -3855,13 +3834,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"through@npm:2":
-  version: 2.3.8
-  resolution: "through@npm:2.3.8"
-  checksum: 10c0/4b09f3774099de0d4df26d95c5821a62faee32c7e96fb1f4ebd54a2d7c11c57fe88b0a0d49cf375de5fee5ae6bf4eb56dbbf29d07366864e2ee805349970d3cc
-  languageName: node
-  linkType: hard
-
 "timsort@npm:^0.3.0":
   version: 0.3.0
   resolution: "timsort@npm:0.3.0"