electron/lib/asar/fs-wrapper.ts

import { Buffer } from 'buffer';
import * as path from 'path';
import * as util from 'util';

const asar = process._linkedBinding('electron_common_asar');
const v8Util = process._linkedBinding('electron_common_v8_util');

const Module = require('module');

const Promise: PromiseConstructor = global.Promise;

const envNoAsar = process.env.ELECTRON_NO_ASAR &&
    process.type !== 'browser' &&
    process.type !== 'renderer';
const isAsarDisabled = () => process.noAsar || envNoAsar;

const internalBinding = process.internalBinding!;
delete process.internalBinding;

const nextTick = (functionToCall: Function, args: any[] = []) => {
  process.nextTick(() => functionToCall(...args));
};

// Cache asar archive objects.
const cachedArchives = new Map<string, NodeJS.AsarArchive>();

const getOrCreateArchive = (archivePath: string) => {
  const isCached = cachedArchives.has(archivePath);
  if (isCached) {
    return cachedArchives.get(archivePath);
  }

  const newArchive = asar.createArchive(archivePath);
  if (!newArchive) return null;

  cachedArchives.set(archivePath, newArchive);
  return newArchive;
};

// Separate asar package's path from full path.
const splitPath = (archivePathOrBuffer: string | Buffer) => {
  // Shortcut for disabled asar.
  if (isAsarDisabled()) return { isAsar: <const>false };

  // Check for a bad argument type.
  let archivePath = archivePathOrBuffer;
  if (Buffer.isBuffer(archivePathOrBuffer)) {
    archivePath = archivePathOrBuffer.toString();
  }
  if (typeof archivePath !== 'string') return { isAsar: <const>false };

  return asar.splitPath(path.normalize(archivePath));
};

// Convert asar archive's Stats object to fs's Stats object.
let nextInode = 0;

const uid = process.getuid != null ? process.getuid() : 0;
const gid = process.getgid != null ? process.getgid() : 0;

const fakeTime = new Date();

const asarStatsToFsStats = function (stats: NodeJS.AsarFileStat) {
  const { Stats, constants } = require('fs');

  let mode = constants.S_IROTH ^ constants.S_IRGRP ^ constants.S_IRUSR ^ constants.S_IWUSR;

  if (stats.isFile) {
    mode ^= constants.S_IFREG;
  } else if (stats.isDirectory) {
    mode ^= constants.S_IFDIR;
  } else if (stats.isLink) {
    mode ^= constants.S_IFLNK;
  }

  return new Stats(
    1, // dev
    mode, // mode
    1, // nlink
    uid,
    gid,
    0, // rdev
    undefined, // blksize
    ++nextInode, // ino
    stats.size,
    undefined, // blocks,
    fakeTime.getTime(), // atim_msec
    fakeTime.getTime(), // mtim_msec
    fakeTime.getTime(), // ctim_msec
    fakeTime.getTime() // birthtim_msec
  );
};

const enum AsarError {
  NOT_FOUND = 'NOT_FOUND',
  NOT_DIR = 'NOT_DIR',
  NO_ACCESS = 'NO_ACCESS',
  INVALID_ARCHIVE = 'INVALID_ARCHIVE'
}

type AsarErrorObject = Error & { code?: string, errno?: number };

const createError = (errorType: AsarError, { asarPath, filePath }: { asarPath?: string, filePath?: string } = {}) => {
  let error: AsarErrorObject;
  switch (errorType) {
    case AsarError.NOT_FOUND:
      error = new Error(`ENOENT, ${filePath} not found in ${asarPath}`);
      error.code = 'ENOENT';
      error.errno = -2;
      break;
    case AsarError.NOT_DIR:
      error = new Error('ENOTDIR, not a directory');
      error.code = 'ENOTDIR';
      error.errno = -20;
      break;
    case AsarError.NO_ACCESS:
      error = new Error(`EACCES: permission denied, access '${filePath}'`);
      error.code = 'EACCES';
      error.errno = -13;
      break;
    case AsarError.INVALID_ARCHIVE:
      error = new Error(`Invalid package ${asarPath}`);
      break;
    default:
      throw new Error(`Invalid error type "${errorType}" passed to createError.`);
  }
  return error;
};

const overrideAPISync = function (module: Record<string, any>, name: string, pathArgumentIndex?: number | null, fromAsync: boolean = false) {
  if (pathArgumentIndex == null) pathArgumentIndex = 0;
  const old = module[name];
  const func = function (this: any, ...args: any[]) {
    const pathArgument = args[pathArgumentIndex!];
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return old.apply(this, args);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) throw createError(AsarError.INVALID_ARCHIVE, { asarPath });

    const newPath = archive.copyFileOut(filePath);
    if (!newPath) throw createError(AsarError.NOT_FOUND, { asarPath, filePath });

    args[pathArgumentIndex!] = newPath;
    return old.apply(this, args);
  };
  if (fromAsync) {
    return func;
  }
  module[name] = func;
};

const overrideAPI = function (module: Record<string, any>, name: string, pathArgumentIndex?: number | null) {
  if (pathArgumentIndex == null) pathArgumentIndex = 0;
  const old = module[name];
  module[name] = function (this: any, ...args: any[]) {
    const pathArgument = args[pathArgumentIndex!];
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return old.apply(this, args);
    const { asarPath, filePath } = pathInfo;

    const callback = args[args.length - 1];
    if (typeof callback !== 'function') {
      return overrideAPISync(module, name, pathArgumentIndex!, true)!.apply(this, args);
    }

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback, [error]);
      return;
    }

    const newPath = archive.copyFileOut(filePath);
    if (!newPath) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    args[pathArgumentIndex!] = newPath;
    return old.apply(this, args);
  };

  if (old[util.promisify.custom]) {
    module[name][util.promisify.custom] = makePromiseFunction(old[util.promisify.custom], pathArgumentIndex);
  }

  if (module.promises && module.promises[name]) {
    module.promises[name] = makePromiseFunction(module.promises[name], pathArgumentIndex);
  }
};

const makePromiseFunction = function (orig: Function, pathArgumentIndex: number) {
  return function (this: any, ...args: any[]) {
    const pathArgument = args[pathArgumentIndex];
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return orig.apply(this, args);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      return Promise.reject(createError(AsarError.INVALID_ARCHIVE, { asarPath }));
    }

    const newPath = archive.copyFileOut(filePath);
    if (!newPath) {
      return Promise.reject(createError(AsarError.NOT_FOUND, { asarPath, filePath }));
    }

    args[pathArgumentIndex] = newPath;
    return orig.apply(this, args);
  };
};

// Override fs APIs.
export const wrapFsWithAsar = (fs: Record<string, any>) => {
  const logFDs = new Map<string, number>();
  const logASARAccess = (asarPath: string, filePath: string, offset: number) => {
    if (!process.env.ELECTRON_LOG_ASAR_READS) return;
    if (!logFDs.has(asarPath)) {
      const path = require('path');
      const logFilename = `${path.basename(asarPath, '.asar')}-access-log.txt`;
      const logPath = path.join(require('os').tmpdir(), logFilename);
      logFDs.set(asarPath, fs.openSync(logPath, 'a'));
    }
    fs.writeSync(logFDs.get(asarPath), `${offset}: ${filePath}\n`);
  };

  const { lstatSync } = fs;
  fs.lstatSync = (pathArgument: string, options: any) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return lstatSync(pathArgument, options);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) throw createError(AsarError.INVALID_ARCHIVE, { asarPath });

    const stats = archive.stat(filePath);
    if (!stats) throw createError(AsarError.NOT_FOUND, { asarPath, filePath });

    return asarStatsToFsStats(stats);
  };

  const { lstat } = fs;
  fs.lstat = function (pathArgument: string, options: any, callback: any) {
    const pathInfo = splitPath(pathArgument);
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
    if (!pathInfo.isAsar) return lstat(pathArgument, options, callback);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback, [error]);
      return;
    }

    const stats = archive.stat(filePath);
    if (!stats) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    const fsStats = asarStatsToFsStats(stats);
    nextTick(callback, [null, fsStats]);
  };

  fs.promises.lstat = util.promisify(fs.lstat);

  const { statSync } = fs;
  fs.statSync = (pathArgument: string, options: any) => {
    const { isAsar } = splitPath(pathArgument);
    if (!isAsar) return statSync(pathArgument, options);

    // Do not distinguish links for now.
    return fs.lstatSync(pathArgument, options);
  };

  const { stat } = fs;
  fs.stat = (pathArgument: string, options: any, callback: any) => {
    const { isAsar } = splitPath(pathArgument);
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
    if (!isAsar) return stat(pathArgument, options, callback);

    // Do not distinguish links for now.
    process.nextTick(() => fs.lstat(pathArgument, options, callback));
  };

  fs.promises.stat = util.promisify(fs.stat);

  const wrapRealpathSync = function (realpathSync: Function) {
    return function (this: any, pathArgument: string, options: any) {
      const pathInfo = splitPath(pathArgument);
      if (!pathInfo.isAsar) return realpathSync.apply(this, arguments);
      const { asarPath, filePath } = pathInfo;

      const archive = getOrCreateArchive(asarPath);
      if (!archive) {
        throw createError(AsarError.INVALID_ARCHIVE, { asarPath });
      }

      const fileRealPath = archive.realpath(filePath);
      if (fileRealPath === false) {
        throw createError(AsarError.NOT_FOUND, { asarPath, filePath });
      }

      return path.join(realpathSync(asarPath, options), fileRealPath);
    };
  };

  const { realpathSync } = fs;
  fs.realpathSync = wrapRealpathSync(realpathSync);
  fs.realpathSync.native = wrapRealpathSync(realpathSync.native);

  const wrapRealpath = function (realpath: Function) {
    return function (this: any, pathArgument: string, options: any, callback: any) {
      const pathInfo = splitPath(pathArgument);
      if (!pathInfo.isAsar) return realpath.apply(this, arguments);
      const { asarPath, filePath } = pathInfo;

      if (arguments.length < 3) {
        callback = options;
        options = {};
      }

      const archive = getOrCreateArchive(asarPath);
      if (!archive) {
        const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
        nextTick(callback, [error]);
        return;
      }

      const fileRealPath = archive.realpath(filePath);
      if (fileRealPath === false) {
        const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
        nextTick(callback, [error]);
        return;
      }

      realpath(asarPath, options, (error: Error | null, archiveRealPath: string) => {
        if (error === null) {
          const fullPath = path.join(archiveRealPath, fileRealPath);
          callback(null, fullPath);
        } else {
          callback(error);
        }
      });
    };
  };

  const { realpath } = fs;
  fs.realpath = wrapRealpath(realpath);
  fs.realpath.native = wrapRealpath(realpath.native);

  fs.promises.realpath = util.promisify(fs.realpath.native);

  const { exists } = fs;
  fs.exists = (pathArgument: string, callback: any) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return exists(pathArgument, callback);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback, [error]);
      return;
    }

    const pathExists = (archive.stat(filePath) !== false);
    nextTick(callback, [pathExists]);
  };

  fs.exists[util.promisify.custom] = (pathArgument: string) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return exists[util.promisify.custom](pathArgument);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      return Promise.reject(error);
    }

    return Promise.resolve(archive.stat(filePath) !== false);
  };

  const { existsSync } = fs;
  fs.existsSync = (pathArgument: string) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return existsSync(pathArgument);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) return false;

    return archive.stat(filePath) !== false;
  };

  const { access } = fs;
  fs.access = function (pathArgument: string, mode: any, callback: any) {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return access.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    if (typeof mode === 'function') {
      callback = mode;
      mode = fs.constants.F_OK;
    }

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback, [error]);
      return;
    }

    const info = archive.getFileInfo(filePath);
    if (!info) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    if (info.unpacked) {
      const realPath = archive.copyFileOut(filePath);
      return fs.access(realPath, mode, callback);
    }

    const stats = archive.stat(filePath);
    if (!stats) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    if (mode & fs.constants.W_OK) {
      const error = createError(AsarError.NO_ACCESS, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    nextTick(callback);
  };

  fs.promises.access = util.promisify(fs.access);

  const { accessSync } = fs;
  fs.accessSync = function (pathArgument: string, mode: any) {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return accessSync.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    if (mode == null) mode = fs.constants.F_OK;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      throw createError(AsarError.INVALID_ARCHIVE, { asarPath });
    }

    const info = archive.getFileInfo(filePath);
    if (!info) {
      throw createError(AsarError.NOT_FOUND, { asarPath, filePath });
    }

    if (info.unpacked) {
      const realPath = archive.copyFileOut(filePath);
      return fs.accessSync(realPath, mode);
    }

    const stats = archive.stat(filePath);
    if (!stats) {
      throw createError(AsarError.NOT_FOUND, { asarPath, filePath });
    }

    if (mode & fs.constants.W_OK) {
      throw createError(AsarError.NO_ACCESS, { asarPath, filePath });
    }
  };

  const { readFile } = fs;
  fs.readFile = function (pathArgument: string, options: any, callback: any) {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return readFile.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    if (typeof options === 'function') {
      callback = options;
      options = { encoding: null };
    } else if (typeof options === 'string') {
      options = { encoding: options };
    } else if (options === null || options === undefined) {
      options = { encoding: null };
    } else if (typeof options !== 'object') {
      throw new TypeError('Bad arguments');
    }

    const { encoding } = options;
    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback, [error]);
      return;
    }

    const info = archive.getFileInfo(filePath);
    if (!info) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback, [error]);
      return;
    }

    if (info.size === 0) {
      nextTick(callback, [null, encoding ? '' : Buffer.alloc(0)]);
      return;
    }

    if (info.unpacked) {
      const realPath = archive.copyFileOut(filePath);
      return fs.readFile(realPath, options, callback);
    }

    logASARAccess(asarPath, filePath, info.offset);
    archive.read(info.offset, info.size).then((buf) => {
      const buffer = Buffer.from(buf);
      callback(null, encoding ? buffer.toString(encoding) : buffer);
    }, (err) => {
      const error: AsarErrorObject = new Error(`EINVAL, ${err.message} while reading ${filePath} in ${asarPath}`);
      error.code = 'EINVAL';
      error.errno = -22;
      callback(error);
    });
  };

  fs.promises.readFile = util.promisify(fs.readFile);

  const { readFileSync } = fs;
  fs.readFileSync = function (pathArgument: string, options: any) {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return readFileSync.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) throw createError(AsarError.INVALID_ARCHIVE, { asarPath });

    const info = archive.getFileInfo(filePath);
    if (!info) throw createError(AsarError.NOT_FOUND, { asarPath, filePath });

    if (info.size === 0) return (options) ? '' : Buffer.alloc(0);
    if (info.unpacked) {
      const realPath = archive.copyFileOut(filePath);
      return fs.readFileSync(realPath, options);
    }

    if (!options) {
      options = { encoding: null };
    } else if (typeof options === 'string') {
      options = { encoding: options };
    } else if (typeof options !== 'object') {
      throw new TypeError('Bad arguments');
    }

    const { encoding } = options;

    logASARAccess(asarPath, filePath, info.offset);
    let arrayBuffer: ArrayBuffer;
    try {
      arrayBuffer = archive.readSync(info.offset, info.size);
    } catch (err) {
      const error: AsarErrorObject = new Error(`EINVAL, ${err.message} while reading ${filePath} in ${asarPath}`);
      error.code = 'EINVAL';
      error.errno = -22;
      throw error;
    }
    const buffer = Buffer.from(arrayBuffer);
    return encoding ? buffer.toString(encoding) : buffer;
  };

  const { readdir } = fs;
  fs.readdir = function (pathArgument: string, options: { encoding?: string | null; withFileTypes?: boolean } = {}, callback?: Function) {
    const pathInfo = splitPath(pathArgument);
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
    if (!pathInfo.isAsar) return readdir.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      const error = createError(AsarError.INVALID_ARCHIVE, { asarPath });
      nextTick(callback!, [error]);
      return;
    }

    const files = archive.readdir(filePath);
    if (!files) {
      const error = createError(AsarError.NOT_FOUND, { asarPath, filePath });
      nextTick(callback!, [error]);
      return;
    }

    if (options.withFileTypes) {
      const dirents = [];
      for (const file of files) {
        const stats = archive.stat(file);
        if (!stats) {
          const error = createError(AsarError.NOT_FOUND, { asarPath, filePath: file });
          nextTick(callback!, [error]);
          return;
        }
        if (stats.isFile) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_FILE));
        } else if (stats.isDirectory) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_DIR));
        } else if (stats.isLink) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_LINK));
        }
      }
      nextTick(callback!, [null, dirents]);
      return;
    }

    nextTick(callback!, [null, files]);
  };

  fs.promises.readdir = util.promisify(fs.readdir);

  const { readdirSync } = fs;
  fs.readdirSync = function (pathArgument: string, options: { encoding: BufferEncoding | null; withFileTypes?: false } | BufferEncoding | null) {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return readdirSync.apply(this, arguments);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) {
      throw createError(AsarError.INVALID_ARCHIVE, { asarPath });
    }

    const files = archive.readdir(filePath);
    if (!files) {
      throw createError(AsarError.NOT_FOUND, { asarPath, filePath });
    }

    if (options && (options as any).withFileTypes) {
      const dirents = [];
      for (const file of files) {
        const stats = archive.stat(file);
        if (!stats) {
          throw createError(AsarError.NOT_FOUND, { asarPath, filePath: file });
        }
        if (stats.isFile) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_FILE));
        } else if (stats.isDirectory) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_DIR));
        } else if (stats.isLink) {
          dirents.push(new fs.Dirent(file, fs.constants.UV_DIRENT_LINK));
        }
      }
      return dirents;
    }

    return files;
  };

  const { internalModuleReadJSON } = internalBinding('fs');
  internalBinding('fs').internalModuleReadJSON = (pathArgument: string) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return internalModuleReadJSON(pathArgument);
    const { asarPath, filePath } = pathInfo;

    const archive = getOrCreateArchive(asarPath);
    if (!archive) return [];

    const info = archive.getFileInfo(filePath);
    if (!info) return [];
    if (info.size === 0) return ['', false];
    if (info.unpacked) {
      const realPath = archive.copyFileOut(filePath);
      return fs.readFileSync(realPath, { encoding: 'utf8' });
    }

    logASARAccess(asarPath, filePath, info.offset);
    let arrayBuffer: ArrayBuffer;
    try {
      arrayBuffer = archive.readSync(info.offset, info.size);
    } catch (err) {
      const error: AsarErrorObject = new Error(`EINVAL, ${err.message} while reading ${filePath} in ${asarPath}`);
      error.code = 'EINVAL';
      error.errno = -22;
      throw error;
    }
    const buffer = Buffer.from(arrayBuffer);
    const str = buffer.toString('utf8');
    return [str, str.length > 0];
  };

  const { internalModuleStat } = internalBinding('fs');
  internalBinding('fs').internalModuleStat = (pathArgument: string) => {
    const pathInfo = splitPath(pathArgument);
    if (!pathInfo.isAsar) return internalModuleStat(pathArgument);
    const { asarPath, filePath } = pathInfo;

    // -ENOENT
    const archive = getOrCreateArchive(asarPath);
    if (!archive) return -34;

    // -ENOENT
    const stats = archive.stat(filePath);
    if (!stats) return -34;

    return (stats.isDirectory) ? 1 : 0;
  };

  // Calling mkdir for directory inside asar archive should throw ENOTDIR
  // error, but on Windows it throws ENOENT.
  if (process.platform === 'win32') {
    const { mkdir } = fs;
    fs.mkdir = (pathArgument: string, options: any, callback: any) => {
      if (typeof options === 'function') {
        callback = options;
        options = {};
      }

      const pathInfo = splitPath(pathArgument);
      if (pathInfo.isAsar && pathInfo.filePath.length > 0) {
        const error = createError(AsarError.NOT_DIR);
        nextTick(callback, [error]);
        return;
      }

      mkdir(pathArgument, options, callback);
    };

    fs.promises.mkdir = util.promisify(fs.mkdir);

    const { mkdirSync } = fs;
    fs.mkdirSync = function (pathArgument: string, options: any) {
      const pathInfo = splitPath(pathArgument);
      if (pathInfo.isAsar && pathInfo.filePath.length) throw createError(AsarError.NOT_DIR);
      return mkdirSync(pathArgument, options);
    };
  }

  function invokeWithNoAsar (func: Function) {
    return function (this: any) {
      const processNoAsarOriginalValue = process.noAsar;
      process.noAsar = true;
      try {
        return func.apply(this, arguments);
      } finally {
        process.noAsar = processNoAsarOriginalValue;
      }
    };
  }

  // Strictly implementing the flags of fs.copyFile is hard, just do a simple
  // implementation for now. Doing 2 copies won't spend much time more as OS
  // has filesystem caching.
  overrideAPI(fs, 'copyFile');
  overrideAPISync(fs, 'copyFileSync');

  overrideAPI(fs, 'open');
  overrideAPISync(process, 'dlopen', 1);
  overrideAPISync(Module._extensions, '.node', 1);
  overrideAPISync(fs, 'openSync');

  const overrideChildProcess = (childProcess: Record<string, any>) => {
    // Executing a command string containing a path to an asar archive
    // confuses `childProcess.execFile`, which is internally called by
    // `childProcess.{exec,execSync}`, causing Electron to consider the full
    // command as a single path to an archive.
    const { exec, execSync } = childProcess;
    childProcess.exec = invokeWithNoAsar(exec);
    childProcess.exec[util.promisify.custom] = invokeWithNoAsar(exec[util.promisify.custom]);
    childProcess.execSync = invokeWithNoAsar(execSync);

    overrideAPI(childProcess, 'execFile');
    overrideAPISync(childProcess, 'execFileSync');
  };

  // Lazily override the child_process APIs only when child_process is
  // fetched the first time.  We will eagerly override the child_process APIs
  // when this env var is set so that stack traces generated inside node unit
  // tests will match. This env var will only slow things down in users apps
  // and should not be used.
  if (process.env.ELECTRON_EAGER_ASAR_HOOK_FOR_TESTING) {
    overrideChildProcess(require('child_process'));
  } else {
    const originalModuleLoad = Module._load;
    Module._load = (request: string, ...args: any[]) => {
      const loadResult = originalModuleLoad(request, ...args);
      if (request === 'child_process') {
        if (!v8Util.getHiddenValue(loadResult, 'asar-ready')) {
          v8Util.setHiddenValue(loadResult, 'asar-ready', true);
          // Just to make it obvious what we are dealing with here
          const childProcess = loadResult;

          overrideChildProcess(childProcess);
        }
      }
      return loadResult;
    };
  }
};