Split code in several files for easier maintenance and testing

Author: piranna

lib/index.js

@@ -0,0 +1,222 @@
+const fs      = require('fs')
+const resolve = require('path').resolve
+
+const each   = require('async/each')
+const jocker = require('jocker')
+const prompt = require('prompt')
+const rimraf = require('rimraf').sync
+const utils  = require('nodeos-mount-utils')
+
+const jocker_root = require('./jocker_root')
+
+const flags     = utils.flags
+const MS_NODEV  = flags.MS_NODEV
+const MS_NOSUID = flags.MS_NOSUID
+
+
+const HOME = '/tmp'
+
+
+/**
+ * This error handler traces the error and starts a node.js repl
+ * @access private
+ * @param  {Error} error The error that gets traced
+ */
+function onerror(error)
+{
+  console.trace(error)
+  utils.startRepl('NodeOS-mount-filesystems')
+}
+
+/**
+ * Filter folders that are valid user `$HOME`
+ * @access private
+ * @param  {String}  user The name of the user
+ * @return {Boolean}      Returns true If the first char is not a dot
+ *                        and not `root` and not ´lost+found´
+ */
+function filterUser(user)
+{
+  return user[0] !== '.' && user !== 'root' && user !== 'lost+found'
+}
+
+/**
+ * This helper waits with a limit of tries until the path exists
+ * @access private
+ * @param  {String}   path     The path to check for
+ * @param  {Number}   tries    A limit of tries
+ * @param  {Function} callback The callback function
+ * @return {Function}          Returns the callback with either nothing
+ *                             or with a error
+ */
+function waitUntilExists(path, tries, callback)
+{
+  fs.exists(path, function(exists)
+  {
+    if(exists) return callback()
+
+    if(tries-- <= 0) return callback(new Error(path+' not exists'))
+
+    setTimeout(waitUntilExists, 1000, path, tries, callback)
+  })
+}
+
+/**
+ * Starts a prompt and asks for the location of the userfs
+ * @access private
+ * @param  {Error} error The error will be printed in the console
+ */
+function askLocation(error)
+{
+  console.warn('Could not find userfs:', error)
+
+  var self = this
+
+  prompt.start()
+  prompt.get('path to userfs', function(error, result)
+  {
+    if(error) console.warn(error)
+
+    self.root = result['path to userfs']
+    return mountUsersFS(self)
+  })
+}
+
+/**
+ * If the `single` key is set in the cmdline it starts a admin repl
+ * If not it just overlays the users filesystem
+ * @access private
+ * @param  {String} usersFolder The path to folder of the users
+ */
+function adminOrUsers(usersFolder)
+{
+  function done(error)
+  {
+    // Remove the modules from initramfs to free memory
+    // rimraf('/lib/node_modules')
+    rimraf('/lib/node_modules/jocker')
+
+    // Make '/usr' a opaque folder (OverlayFS feature)
+    rimraf('/usr')
+
+    if(error) onerror(error)
+  }
+
+  // Mount users directories and exec their init files
+  fs.readdir(usersFolder, function(error, users)
+  {
+    if(error) return done(error)
+
+    each(users.filter(filterUser), function(username, callback)
+    {
+      jocker.run(usersFolder+'/'+username, '/init', {PATH: '/bin'}, callback)
+    },
+    done)
+  })
+}
+
+/**
+ * Prepares the session and checks if the users filesystem has a root account,
+ * if not check if `/proc/cmdline` has the single key
+ * It deletes the `root`, `rootfstype` and `vga` environment variables
+ * and adds `NODE_PATH` to it.
+ * @access private
+ * @return {Repl} Returns either a repl or a error if the error contains
+ *                a `ENOENT` code
+ */
+function prepareSessions()
+{
+  // Update environment variables
+  var env = process.env
+
+  delete env['root']
+  delete env['rootfstype']
+  delete env['vga']
+
+  env['NODE_PATH'] = '/lib/node_modules'
+
+  const upperdir = HOME+'/root'
+
+  // Check if users filesystem has an administrator account
+  fs.readdir(upperdir, function(error)
+  {
+    if(error)
+    {
+      if(error.code !== 'ENOENT') return onerror(error)
+
+      return adminOrUsers(HOME)
+    }
+
+    // There's an administrator account, prepare it first
+    jocker_root.create(upperdir, function(error, newHome)
+    {
+      if(error) return onerror(error)
+
+      // Enter administrator mode
+      if(exports.single) return utils.startRepl('Administrator mode')
+
+      // Execute `root` user init in un-priviledged environment
+      jocker.exec(HOME, '/init', {PATH: '/bin'}, function(error)
+      {
+        if(error) console.warn(error)
+
+        adminOrUsers(newHome)
+      })
+    })
+  })
+}
+
+/**
+ * This function mounts the userfs
+ * if the root env variable contains `container` it prepares the session
+ * and if there is no root env var then it awaits the user device and
+ * then mounts the user device and then prepares the session
+ * @access private
+ * @param  {Object}       cmdline This objects holds key/value pairs from the
+ *                                `/proc/cmdline` file
+ * @return {Prompt|Error}         It returns either a prompt if the
+ *                                tries has reached its limit or a error
+ *                                if the `mkdirMount` fails to create the user
+ *                                device
+ */
+function mountUsersFS(cmdline)
+{
+  // Allow to override or disable `usersDev`
+  var usersDev = process.env.root
+  if(usersDev === undefined) usersDev = cmdline.root
+
+  // Running on a container (Docker, vagga), don't mount the users filesystem
+  if(usersDev === 'container') return prepareSessions()
+
+  // Running on real hardware or virtual machine, mount the users filesystem
+  if(usersDev)
+    waitUntilExists(usersDev, 5, function(error)
+    {
+      if(error) return askLocation.call(cmdline, error)
+
+      // Mount users filesystem
+      var type   = process.env.rootfstype || cmdline.rootfstype || 'auto'
+      var extras = {errors: 'remount-ro', devFile: resolve(usersDev)}
+
+      utils.mkdirMount(HOME, type, MS_NODEV | MS_NOSUID, extras, function(error)
+      {
+        if(error) return onerror(error)
+
+        prepareSessions()
+      })
+    })
+
+  // Users filesystem is not defined, launch a Node.js REPL
+  else
+    fs.readFile('resources/readonly_warning.txt', 'utf8', function(error, data)
+    {
+      if(error) return onerror(error)
+
+      console.warn(data)
+      utils.startRepl('NodeOS-mount-filesystems')
+    })
+}
+
+
+exports.mountUsersFS = mountUsersFS
+exports.single       = false