overleaf/services/filestore/app/js/SafeExec.js

/* eslint-disable
    camelcase,
    handle-callback-err,
    no-return-assign,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
 * decaffeinate suggestions:
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
const _ = require('underscore')
const logger = require('logger-sharelatex')
const child_process = require('child_process')
const Settings = require('settings-sharelatex')

// execute a command in the same way as 'exec' but with a timeout that
// kills all child processes
//
// we spawn the command with 'detached:true' to make a new process
// group, then we can kill everything in that process group.

module.exports = function(command, options, callback) {
  if (callback == null) {
    callback = function(err, stdout, stderr) {}
  }
  if (!Settings.enableConversions) {
    const error = new Error('Image conversions are disabled')
    return callback(error)
  }

  // options are {timeout:  number-of-milliseconds, killSignal: signal-name}
  const [cmd, ...args] = Array.from(command)

  const child = child_process.spawn(cmd, args, { detached: true })
  let stdout = ''
  let stderr = ''

  const cleanup = _.once(function(err) {
    if (killTimer != null) {
      clearTimeout(killTimer)
    }
    return callback(err, stdout, stderr)
  })

  if (options.timeout != null) {
    var killTimer = setTimeout(function() {
      try {
        // use negative process id to kill process group
        return process.kill(-child.pid, options.killSignal || 'SIGTERM')
      } catch (error) {
        return logger.log(
          { process: child.pid, kill_error: error },
          'error killing process'
        )
      }
    }, options.timeout)
  }

  child.on('close', function(code, signal) {
    const err = code ? new Error(`exit status ${code}`) : signal
    return cleanup(err)
  })

  child.on('error', err => cleanup(err))

  child.stdout.on('data', chunk => (stdout += chunk))

  return child.stderr.on('data', chunk => (stderr += chunk))
}