CSE2410 Fall 2014 Bounce

// Copyright Joyent, Inc. and other Node contributors.

//

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

//

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

var EventEmitter = require('events').EventEmitter;

var net = require('net');

var Process = process.binding('process_wrap').Process;

var util = require('util');

var constants; // if (!constants) constants = process.binding('constants');

var handleWraps = {};

function handleWrapGetter(name, callback) {

  var cons;

  Object.defineProperty(handleWraps, name, {

    get: function() {

      if (cons !== undefined) return cons;

      return cons = callback();

    }

  });

}

handleWrapGetter('Pipe', function() {

  return process.binding('pipe_wrap').Pipe;

});

handleWrapGetter('TTY', function() {

  return process.binding('tty_wrap').TTY;

});

handleWrapGetter('TCP', function() {

  return process.binding('tcp_wrap').TCP;

});

handleWrapGetter('UDP', function() {

  return process.binding('udp_wrap').UDP;

});

// constructors for lazy loading

function createPipe(ipc) {

  return new handleWraps.Pipe(ipc);

}

function createSocket(pipe, readable) {

  var s = new net.Socket({ handle: pipe });

  if (readable) {

    s.writable = false;

    s.readable = true;

  } else {

    s.writable = true;

    s.readable = false;

  }

  return s;

}

// this object contain function to convert TCP objects to native handle objects

// and back again.

var handleConversion = {

  'net.Native': {

    simultaneousAccepts: true,

    send: function(message, handle) {

      return handle;

    },

    got: function(message, handle, emit) {

      emit(handle);

    }

  },

  'net.Server': {

    simultaneousAccepts: true,

    send: function(message, server) {

      return server._handle;

    },

    got: function(message, handle, emit) {

      var self = this;

      var server = new net.Server();

      server.listen(handle, function() {

        emit(server);

      });

    }

  },

  'net.Socket': {

    send: function(message, socket) {

      // if the socket was created by net.Server

      if (socket.server) {

        // the slave should keep track of the socket

        message.key = socket.server._connectionKey;

        var firstTime = !this._channel.sockets.send[message.key];

        var socketList = getSocketList('send', this, message.key);

        // the server should no longer expose a .connection property

        // and when asked to close it should query the socket status from

        // the slaves

        if (firstTime) socket.server._setupSlave(socketList);

        // Act like socket is detached

        socket.server._connections--;

      }

      // remove handle from socket object, it will be closed when the socket

      // will be sent

      var handle = socket._handle;

      handle.onread = function() {};

      socket._handle = null;

      return handle;

    },

    postSend: function(handle) {

      // Close the Socket handle after sending it

      handle.close();

    },

    got: function(message, handle, emit) {

      var socket = new net.Socket({handle: handle});

      socket.readable = socket.writable = true;

      // if the socket was created by net.Server we will track the socket

      if (message.key) {

        // add socket to connections list

        var socketList = getSocketList('got', this, message.key);

        socketList.add({

          socket: socket

        });

      }

      emit(socket);

    }

  }

};

// This object keep track of the socket there are sended

function SocketListSend(slave, key) {

  EventEmitter.call(this);

  var self = this;

  this.key = key;

  this.slave = slave;

}

util.inherits(SocketListSend, EventEmitter);

SocketListSend.prototype._request = function(msg, cmd, callback) {

  var self = this;

  if (!this.slave.connected) return onclose();

  this.slave.send(msg);

  function onclose() {

    self.slave.removeListener('internalMessage', onreply);

    callback(new Error('Slave closed before reply'));

  };

  function onreply(msg) {

    if (!(msg.cmd === cmd && msg.key === self.key)) return;

    self.slave.removeListener('disconnect', onclose);

    self.slave.removeListener('internalMessage', onreply);

    callback(null, msg);

  };

  this.slave.once('disconnect', onclose);

  this.slave.on('internalMessage', onreply);

};

SocketListSend.prototype.close = function close(callback) {

  this._request({

    cmd: 'NODE_SOCKET_NOTIFY_CLOSE',

    key: this.key

  }, 'NODE_SOCKET_ALL_CLOSED', callback);

};

SocketListSend.prototype.getConnections = function getConnections(callback) {

  this._request({

    cmd: 'NODE_SOCKET_GET_COUNT',

    key: this.key

  }, 'NODE_SOCKET_COUNT', function(err, msg) {

    if (err) return callback(err);

    callback(null, msg.count);

  });

};

// This object keep track of the socket there are received

function SocketListReceive(slave, key) {

  EventEmitter.call(this);

  var self = this;

  this.connections = 0;

  this.key = key;

  this.slave = slave;

  function onempty() {

    if (!self.slave.connected) return;

    self.slave.send({

      cmd: 'NODE_SOCKET_ALL_CLOSED',

      key: self.key

    });

  }

  this.slave.on('internalMessage', function(msg) {

    if (msg.key !== self.key) return;

    if (msg.cmd === 'NODE_SOCKET_NOTIFY_CLOSE') {

      // Already empty

      if (self.connections === 0) return onempty();

      // Wait for sockets to get closed

      self.once('empty', onempty);

    } else if (msg.cmd === 'NODE_SOCKET_GET_COUNT') {

      if (!self.slave.connected) return;

      self.slave.send({

        cmd: 'NODE_SOCKET_COUNT',

        key: self.key,

        count: self.connections

      });

    }

  });

}

util.inherits(SocketListReceive, EventEmitter);

SocketListReceive.prototype.add = function(obj) {

  var self = this;

  this.connections++;

  // Notify previous owner of socket about its state change

  obj.socket.once('close', function() {

    self.connections--;

    if (self.connections === 0) self.emit('empty');

  });

};

function getSocketList(type, slave, key) {

  var sockets = slave._channel.sockets[type];

  var socketList = sockets[key];

  if (!socketList) {

    var Construct = type === 'send' ? SocketListSend : SocketListReceive;

    socketList = sockets[key] = new Construct(slave, key);

  }

  return socketList;

}

function handleMessage(target, message, handle) {

  //Filter out internal messages

  //if cmd property begin with "_NODE"

  if (message !== null &&

      typeof message === 'object' &&

      typeof message.cmd === 'string' &&

      message.cmd.indexOf('NODE_') === 0) {

    target.emit('internalMessage', message, handle);

  }

  //Non-internal message

  else {

    target.emit('message', message, handle);

  }

}

function setupChannel(target, channel) {

  target._channel = channel;

  var jsonBuffer = '';

  channel.buffering = false;

  channel.onread = function(pool, offset, length, recvHandle) {

    if (pool) {

      jsonBuffer += pool.toString('ascii', offset, offset + length);

      var i, start = 0;

      //Linebreak is used as a message end sign

      while ((i = jsonBuffer.indexOf('\n', start)) >= 0) {

        var json = jsonBuffer.slice(start, i);

        var message = JSON.parse(json);

        handleMessage(target, message, recvHandle);

        start = i + 1;

      }

      jsonBuffer = jsonBuffer.slice(start);

      this.buffering = jsonBuffer.length !== 0;

    } else {

      this.buffering = false;

      target.disconnect();

      channel.onread = nop;

      channel.close();

      maybeClose(target);

    }

  };

  // object where socket lists will live

  channel.sockets = { got: {}, send: {} };

  // handlers will go through this

  target.on('internalMessage', function(message, handle) {

    if (message.cmd !== 'NODE_HANDLE') return;

    var obj = handleConversion[message.type];

    // Update simultaneous accepts on Windows

    if (process.platform === 'win32') {

      handle._simultaneousAccepts = false;

      net._setSimultaneousAccepts(handle);

    }

    // Convert handle object

    obj.got.call(this, message, handle, function(handle) {

      handleMessage(target, message.msg, handle);

    });

  });

  target.send = function(message, handle) {

    if (typeof message === 'undefined') {

      throw new TypeError('message cannot be undefined');

    }

    if (!this.connected) {

      this.emit('error', new Error('channel closed'));

      return;

    }

    // package messages with a handle object

    if (handle) {

      // this message will be handled by an internalMessage event handler

      message = {

        cmd: 'NODE_HANDLE',

        type: 'net.',

        msg: message

      };

      switch (handle.constructor.name) {

        case 'Socket':

          message.type += 'Socket'; break;

        case 'Server':

          message.type += 'Server'; break;

        case 'Pipe':

        case 'TCP':

          message.type += 'Native'; break;

      }

      var obj = handleConversion[message.type];

      // convert TCP object to native handle object

      handle = handleConversion[message.type].send.apply(target, arguments);

      // Update simultaneous accepts on Windows

      if (obj.simultaneousAccepts) {

        net._setSimultaneousAccepts(handle);

      }

    }

    var string = JSON.stringify(message) + '\n';

    var writeReq = channel.writeUtf8String(string, handle);

    if (!writeReq) {

      var er = errnoException(errno, 'write', 'cannot write to IPC channel.');

      this.emit('error', er);

    }

    if (obj && obj.postSend) {

      writeReq.oncomplete = obj.postSend.bind(null, handle);

    } else {

      writeReq.oncomplete = nop;

    }

    /* If the master is > 2 read() calls behind, please stop sending. */

    return channel.writeQueueSize < (65536 * 2);

  };

  target.connected = true;

  target.disconnect = function() {

    if (!this.connected) {

      this.emit('error', new Error('IPC channel is already disconnected'));

      return;

    }

    // do not allow messages to be written

    this.connected = false;

    this._channel = null;

    var fired = false;

    function finish() {

      if (fired) return;

      fired = true;

      channel.close();

      target.emit('disconnect');

    }

    // If a message is being read, then wait for it to complete.

    if (channel.buffering) {

      this.once('message', finish);

      this.once('internalMessage', finish);

      return;

    }

    finish();

  };

  channel.readStart();

}

function nop() { }

exports.fork = function(modulePath /*, args, options*/) {

  // Get options and args arguments.

  var options, args, execArgv;

  if (Array.isArray(arguments[1])) {

    args = arguments[1];

    options = util._extend({}, arguments[2]);

  } else {

    args = [];

    options = util._extend({}, arguments[1]);

  }

  // Prepare arguments for fork:

  execArgv = options.execArgv || process.execArgv;

  args = execArgv.concat([modulePath], args);

  // Leave stdin open for the IPC channel. stdout and stderr should be the

  // same as the parent's if silent isn't set.

  options.stdio = options.silent ? ['pipe', 'pipe', 'pipe', 'ipc'] :

      [0, 1, 2, 'ipc'];

  options.execPath = options.execPath || process.execPath;

  return spawn(options.execPath, args, options);

};

exports._forkChild = function(fd) {

  // set process.send()

  var p = createPipe(true);

  p.open(fd);

  p.unref();

  setupChannel(process, p);

  var refs = 0;

  process.on('newListener', function(name) {

    if (name !== 'message' && name !== 'disconnect') return;

    if (++refs === 1) p.ref();

  });

  process.on('removeListener', function(name) {

    if (name !== 'message' && name !== 'disconnect') return;

    if (--refs === 0) p.unref();

  });

};

exports.exec = function(command /*, options, callback */) {

  var file, args, options, callback;

  if (typeof arguments[1] === 'function') {

    options = undefined;

    callback = arguments[1];

  } else {

    options = arguments[1];

    callback = arguments[2];

  }

  if (process.platform === 'win32') {

    file = 'cmd.exe';

    args = ['/s', '/c', '"' + command + '"'];

    // Make a shallow copy before patching so we don't clobber the user's

    // options object.

    options = util._extend({}, options);

    options.windowsVerbatimArguments = true;

  } else {

    file = '/bin/sh';

    args = ['-c', command];

  }

  return exports.execFile(file, args, options, callback);

};

exports.execFile = function(file /* args, options, callback */) {

  var args, optionArg, callback;

  var options = {

    encoding: 'utf8',

    timeout: 0,

    maxBuffer: 200 * 1024,

    killSignal: 'SIGTERM',

    cwd: null,

    env: null

  };

  // Parse the parameters.

  if (typeof arguments[arguments.length - 1] === 'function') {

    callback = arguments[arguments.length - 1];

  }

  if (Array.isArray(arguments[1])) {

    args = arguments[1];

    options = util._extend(options, arguments[2]);

  } else {

    args = [];

    options = util._extend(options, arguments[1]);

  }

  var child = spawn(file, args, {

    cwd: options.cwd,

    env: options.env,

    windowsVerbatimArguments: !!options.windowsVerbatimArguments

  });

  var stdout = '';

  var stderr = '';

  var killed = false;

  var exited = false;

  var timeoutId;

  var err;

  function exithandler(code, signal) {

    if (exited) return;

    exited = true;

    if (timeoutId) {

      clearTimeout(timeoutId);

      timeoutId = null;

    }

    if (!callback) return;

    if (err) {

      callback(err, stdout, stderr);

    } else if (code === 0 && signal === null) {

      callback(null, stdout, stderr);

    } else {

      var e = new Error('Command failed: ' + stderr);

      e.killed = child.killed || killed;

      e.code = code;

      e.signal = signal;

      callback(e, stdout, stderr);

    }

  }

  function errorhandler(e) {

    err = e;

    child.stdout.destroy();

    child.stderr.destroy();

    exithandler();

  }

  function kill() {

    child.stdout.destroy();

    child.stderr.destroy();

    killed = true;

    try {

      child.kill(options.killSignal);

    } catch (e) {

      err = e;

      exithandler();

    }

  }

  if (options.timeout > 0) {

    timeoutId = setTimeout(function() {

      kill();

      timeoutId = null;

    }, options.timeout);

  }

  child.stdout.setEncoding(options.encoding);

  child.stderr.setEncoding(options.encoding);

  child.stdout.addListener('data', function(chunk) {

    stdout += chunk;

    if (stdout.length > options.maxBuffer) {

      err = new Error('stdout maxBuffer exceeded.');

      kill();

    }

  });

  child.stderr.addListener('data', function(chunk) {

    stderr += chunk;

    if (stderr.length > options.maxBuffer) {

      err = new Error('stderr maxBuffer exceeded.');

      kill();

    }

  });

  child.addListener('close', exithandler);

  child.addListener('error', errorhandler);

  return child;

};

var spawn = exports.spawn = function(file, args, options) {

  args = args ? args.slice(0) : [];

  args.unshift(file);

  var env = (options ? options.env : null) || process.env;

  var envPairs = [];

  for (var key in env) {

    envPairs.push(key + '=' + env[key]);

  }

  var child = new ChildProcess();

  if (options && options.customFds && !options.stdio) {

    options.stdio = options.customFds.map(function(fd) {

      return fd === -1 ? 'pipe' : fd;

    });

  }

  child.spawn({

    file: file,

    args: args,

    cwd: options ? options.cwd : null,

    windowsVerbatimArguments: !!(options && options.windowsVerbatimArguments),

    detached: !!(options && options.detached),

    envPairs: envPairs,

    stdio: options ? options.stdio : null,

    uid: options ? options.uid : null,

    gid: options ? options.gid : null

  });

  return child;

};

function maybeClose(subprocess) {

  subprocess._closesGot++;

  if (subprocess._closesGot == subprocess._closesNeeded) {

    subprocess.emit('close', subprocess.exitCode, subprocess.signalCode);

  }

}

function ChildProcess() {

  EventEmitter.call(this);

  // Initialize TCPWrap and PipeWrap

  process.binding('tcp_wrap');

  process.binding('pipe_wrap');

  var self = this;

  this._closesNeeded = 1;

  this._closesGot = 0;

  this.connected = false;

  this.signalCode = null;

  this.exitCode = null;

  this.killed = false;

  this._handle = new Process();

  this._handle.owner = this;

  this._handle.onexit = function(exitCode, signalCode) {

    //

    // follow 0.4.x behaviour:

    //

    // - normally terminated processes don't touch this.signalCode

    // - signaled processes don't touch this.exitCode

    //

    // new in 0.9.x:

    //

    // - spawn failures are reported with exitCode == -1

    //

    var err = (exitCode == -1) ? errnoException(errno, 'spawn') : null;

    if (signalCode) {

      self.signalCode = signalCode;

    } else {

      self.exitCode = exitCode;

    }

    if (self.stdin) {

      self.stdin.destroy();

    }

    self._handle.close();

    self._handle = null;

    if (exitCode == -1) {

      self.emit('error', err);

    } else {

      self.emit('exit', self.exitCode, self.signalCode);

    }

    // if any of the stdio streams have not been touched,

    // then pull all the data through so that it can get the

    // eof and emit a 'close' event.

    // Do it on nextTick so that the user has one last chance

    // to consume the output, if for example they only want to

    // start reading the data once the process exits.

    process.nextTick(function() {

      flushStdio(self);

    });

    maybeClose(self);

  };

}

util.inherits(ChildProcess, EventEmitter);

function flushStdio(subprocess) {

  subprocess.stdio.forEach(function(stream, fd, stdio) {

    if (!stream || !stream.readable || stream._consuming ||

        stream._readableState.flowing)

      return;

    stream.resume();

  });

}

function getHandleWrapType(stream) {

  if (stream instanceof handleWraps.Pipe) return 'pipe';

  if (stream instanceof handleWraps.TTY) return 'tty';

  if (stream instanceof handleWraps.TCP) return 'tcp';

  if (stream instanceof handleWraps.UDP) return 'udp';

  return false;

}

ChildProcess.prototype.spawn = function(options) {

  var self = this,

      ipc,

      ipcFd,

      // If no `stdio` option was given - use default

      stdio = options.stdio || 'pipe';

  // Replace shortcut with an array

  if (typeof stdio === 'string') {

    switch (stdio) {

      case 'ignore': stdio = ['ignore', 'ignore', 'ignore']; break;

      case 'pipe': stdio = ['pipe', 'pipe', 'pipe']; break;

      case 'inherit': stdio = [0, 1, 2]; break;

      default: throw new TypeError('Incorrect value of stdio option: ' + stdio);

    }

  } else if (!Array.isArray(stdio)) {

    throw new TypeError('Incorrect value of stdio option: ' + stdio);

  }

  // At least 3 stdio will be created

  // Don't concat() a new Array() because it would be sparse, and

  // stdio.reduce() would skip the sparse elements of stdio.

  // See http://stackoverflow.com/a/5501711/3561

  while (stdio.length < 3) stdio.push(undefined);

  // Translate stdio into C++-readable form

  // (i.e. PipeWraps or fds)

  stdio = stdio.reduce(function(acc, stdio, i) {

    function cleanup() {

      acc.filter(function(stdio) {

        return stdio.type === 'pipe' || stdio.type === 'ipc';

      }).forEach(function(stdio) {

        stdio.handle.close();

      });

    }

    // Defaults

    if (stdio === undefined || stdio === null) {

      stdio = i < 3 ? 'pipe' : 'ignore';

    }

    if (stdio === 'ignore') {

      acc.push({type: 'ignore'});

    } else if (stdio === 'pipe' || typeof stdio === 'number' && stdio < 0) {

      acc.push({type: 'pipe', handle: createPipe()});

    } else if (stdio === 'ipc') {

      if (ipc !== undefined) {

        // Cleanup previously created pipes

        cleanup();

        throw Error('Child process can have only one IPC pipe');

      }

      ipc = createPipe(true);

      ipcFd = i;

      acc.push({ type: 'pipe', handle: ipc, ipc: true });

    } else if (typeof stdio === 'number' || typeof stdio.fd === 'number') {

      acc.push({ type: 'fd', fd: stdio.fd || stdio });

    } else if (getHandleWrapType(stdio) || getHandleWrapType(stdio.handle) ||

               getHandleWrapType(stdio._handle)) {

      var handle = getHandleWrapType(stdio) ?

          stdio :

          getHandleWrapType(stdio.handle) ? stdio.handle : stdio._handle;

      acc.push({

        type: 'wrap',

        wrapType: getHandleWrapType(handle),

        handle: handle

      });

    } else {

      // Cleanup

      cleanup();

      throw new TypeError('Incorrect value for stdio stream: ' + stdio);

    }

    return acc;

  }, []);

  options.stdio = stdio;

  if (ipc !== undefined) {

    // Let child process know about opened IPC channel

    options.envPairs = options.envPairs || [];

    options.envPairs.push('NODE_CHANNEL_FD=' + ipcFd);

  }

  var r = this._handle.spawn(options);

  if (r) {

    // Close all opened fds on error

    stdio.forEach(function(stdio) {

      if (stdio.type === 'pipe') {

        stdio.handle.close();

      }

    });

    this._handle.close();

    this._handle = null;

    throw errnoException(errno, 'spawn');

  }

  this.pid = this._handle.pid;

  stdio.forEach(function(stdio, i) {

    if (stdio.type === 'ignore') return;

    if (stdio.ipc) {

      self._closesNeeded++;

      return;

    }

    if (stdio.handle) {

      // when i === 0 - we're dealing with stdin

      // (which is the only one writable pipe)

      stdio.socket = createSocket(stdio.handle, i > 0);

      if (i > 0) {

        self._closesNeeded++;

        stdio.socket.on('close', function() {

          maybeClose(self);

        });

      }

    }

  });

  this.stdin = stdio.length >= 1 && stdio[0].socket !== undefined ?

      stdio[0].socket : null;

  this.stdout = stdio.length >= 2 && stdio[1].socket !== undefined ?

      stdio[1].socket : null;

  this.stderr = stdio.length >= 3 && stdio[2].socket !== undefined ?

      stdio[2].socket : null;

  this.stdio = stdio.map(function(stdio) {

    return stdio.socket === undefined ? null : stdio.socket;

  });

  // Add .send() method and start listening for IPC data

  if (ipc !== undefined) setupChannel(this, ipc);

  return r;

};

function errnoException(errorno, syscall, errmsg) {

  // TODO make this more compatible with ErrnoException from src/node.cc

  // Once all of Node is using this function the ErrnoException from

  // src/node.cc should be removed.

  var message = syscall + ' ' + errorno;

  if (errmsg) {

    message += ' - ' + errmsg;

  }

  var e = new Error(message);

  e.errno = e.code = errorno;

  e.syscall = syscall;

  return e;

}

ChildProcess.prototype.kill = function(sig) {

  var signal;

  if (!constants) {

    constants = process.binding('constants');

  }

  if (sig === 0) {

    signal = 0;

  } else if (!sig) {

    signal = constants['SIGTERM'];

  } else {

    signal = constants[sig];

  }

  if (signal === undefined) {

    throw new Error('Unknown signal: ' + sig);

  }

  if (this._handle) {

    var r = this._handle.kill(signal);

    if (r == 0) {

      /* Success. */

      this.killed = true;

      return true;

    } else if (errno == 'ESRCH') {

      /* Already dead. */

    } else if (errno == 'EINVAL' || errno == 'ENOSYS') {

      /* The underlying platform doesn't support this signal. */

      throw errnoException(errno, 'kill');

    } else {

      /* Other error, almost certainly EPERM. */

      this.emit('error', errnoException(errno, 'kill'));

    }

  }

  /* Kill didn't succeed. */

  return false;

};

ChildProcess.prototype.ref = function() {

  if (this._handle) this._handle.ref();

};

ChildProcess.prototype.unref = function() {

  if (this._handle) this._handle.unref();

};