141 lines
3.6 KiB
TypeScript
141 lines
3.6 KiB
TypeScript
import { Hook } from "./types.ts";
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import { EventEmitter } from "./event.ts";
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import type { SandboxFactory } from "./sandbox.ts";
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import { Plug } from "./plug.ts";
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export interface SysCallMapping {
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[key: string]: (ctx: SyscallContext, ...args: any) => Promise<any> | any;
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}
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export type SystemEvents<HookT> = {
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plugLoaded: (plug: Plug<HookT>) => void | Promise<void>;
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plugUnloaded: (name: string) => void | Promise<void>;
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};
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// Passed to every syscall, allows to pass in additional context that the syscall may use
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export type SyscallContext = {
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plug: Plug<any>;
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};
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type SyscallSignature = (
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ctx: SyscallContext,
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...args: any[]
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) => Promise<any> | any;
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type Syscall = {
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requiredPermissions: string[];
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callback: SyscallSignature;
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};
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export class System<HookT> extends EventEmitter<SystemEvents<HookT>> {
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protected plugs = new Map<string, Plug<HookT>>();
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protected registeredSyscalls = new Map<string, Syscall>();
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protected enabledHooks = new Set<Hook<HookT>>();
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constructor(readonly env?: string) {
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super();
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}
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get loadedPlugs(): Map<string, Plug<HookT>> {
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return this.plugs;
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}
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addHook(feature: Hook<HookT>) {
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this.enabledHooks.add(feature);
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feature.apply(this);
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}
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registerSyscalls(
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requiredCapabilities: string[],
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...registrationObjects: SysCallMapping[]
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) {
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for (const registrationObject of registrationObjects) {
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for (const [name, callback] of Object.entries(registrationObject)) {
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this.registeredSyscalls.set(name, {
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requiredPermissions: requiredCapabilities,
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callback,
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});
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}
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}
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}
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syscallWithContext(
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ctx: SyscallContext,
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name: string,
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args: any[],
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): Promise<any> {
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const syscall = this.registeredSyscalls.get(name);
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if (!syscall) {
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throw Error(`Unregistered syscall ${name}`);
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}
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for (const permission of syscall.requiredPermissions) {
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if (!ctx.plug) {
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throw Error(`Syscall ${name} requires permission and no plug is set`);
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}
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if (!ctx.plug.grantedPermissions.includes(permission)) {
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throw Error(`Missing permission '${permission}' for syscall ${name}`);
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}
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}
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return Promise.resolve(syscall.callback(ctx, ...args));
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}
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localSyscall(
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contextPlugName: string,
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syscallName: string,
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args: any[],
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): Promise<any> {
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return this.syscallWithContext(
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// Mock the plug
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{ plug: { name: contextPlugName } as any },
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syscallName,
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args,
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);
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}
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async load(
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workerUrl: URL,
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sandboxFactory: SandboxFactory<HookT>,
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): Promise<Plug<HookT>> {
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const plug = new Plug(this, workerUrl, sandboxFactory);
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// Wait for worker to boot, and pass back its manifest
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await plug.ready;
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// and there it is!
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const manifest = plug.manifest!;
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// Validate the manifest
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let errors: string[] = [];
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for (const feature of this.enabledHooks) {
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errors = [...errors, ...feature.validateManifest(plug.manifest!)];
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}
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if (errors.length > 0) {
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throw new Error(`Invalid manifest: ${errors.join(", ")}`);
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}
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if (this.plugs.has(manifest.name)) {
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this.unload(manifest.name);
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}
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console.log("Loaded plug", manifest.name);
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this.plugs.set(manifest.name, plug);
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await this.emit("plugLoaded", plug);
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return plug;
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}
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unload(name: string) {
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// console.log("Unloading", name);
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const plug = this.plugs.get(name);
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if (!plug) {
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return;
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}
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plug.stop();
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this.emit("plugUnloaded", name);
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this.plugs.delete(name);
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}
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unloadAll(): Promise<void[]> {
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return Promise.all(
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Array.from(this.plugs.keys()).map(this.unload.bind(this)),
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);
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}
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}
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