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nodejs/lib/internal/child_process.js

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'use strict';
const errors = require('internal/errors');
const StringDecoder = require('string_decoder').StringDecoder;
const EventEmitter = require('events');
const net = require('net');
const dgram = require('dgram');
const util = require('util');
const assert = require('assert');
const Process = process.binding('process_wrap').Process;
const WriteWrap = process.binding('stream_wrap').WriteWrap;
const uv = process.binding('uv');
const Pipe = process.binding('pipe_wrap').Pipe;
const TTY = process.binding('tty_wrap').TTY;
const TCP = process.binding('tcp_wrap').TCP;
const UDP = process.binding('udp_wrap').UDP;
const SocketList = require('internal/socket_list');
const { isUint8Array } = process.binding('util');
const { convertToValidSignal } = require('internal/util');
const spawn_sync = process.binding('spawn_sync');
const errnoException = util._errnoException;
const SocketListSend = SocketList.SocketListSend;
const SocketListReceive = SocketList.SocketListReceive;
// this object contain function to convert TCP objects to native handle objects
// and back again.
const handleConversion = {
'net.Native': {
simultaneousAccepts: true,
send: function(message, handle, options) {
return handle;
},
got: function(message, handle, emit) {
emit(handle);
}
},
'net.Server': {
simultaneousAccepts: true,
send: function(message, server, options) {
return server._handle;
},
got: function(message, handle, emit) {
var server = new net.Server();
server.listen(handle, function() {
emit(server);
});
}
},
'net.Socket': {
send: function(message, socket, options) {
if (!socket._handle)
return;
// 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
if (!options.keepOpen)
socket.server._connections--;
}
var handle = socket._handle;
// remove handle from socket object, it will be closed when the socket
// will be sent
if (!options.keepOpen) {
handle.onread = nop;
socket._handle = null;
}
return handle;
},
postSend: function(handle, options, target) {
// Store the handle after successfully sending it, so it can be closed
// when the NODE_HANDLE_ACK is received. If the handle could not be sent,
// just close it.
if (handle && !options.keepOpen) {
if (target) {
// There can only be one _pendingHandle as passing handles are
// processed one at a time: handles are stored in _handleQueue while
// waiting for the NODE_HANDLE_ACK of the current passing handle.
assert(!target._pendingHandle);
target._pendingHandle = handle;
} else {
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);
}
},
'dgram.Native': {
simultaneousAccepts: false,
send: function(message, handle, options) {
return handle;
},
got: function(message, handle, emit) {
emit(handle);
}
},
'dgram.Socket': {
simultaneousAccepts: false,
send: function(message, socket, options) {
message.dgramType = socket.type;
return socket._handle;
},
got: function(message, handle, emit) {
var socket = new dgram.Socket(message.dgramType);
socket.bind(handle, function() {
emit(socket);
});
}
}
};
function ChildProcess() {
EventEmitter.call(this);
this._closesNeeded = 1;
this._closesGot = 0;
this.connected = false;
this.signalCode = null;
this.exitCode = null;
this.killed = false;
this.spawnfile = null;
this._handle = new Process();
this._handle.owner = this;
this._handle.onexit = (exitCode, signalCode) => {
if (signalCode) {
this.signalCode = signalCode;
} else {
this.exitCode = exitCode;
}
if (this.stdin) {
this.stdin.destroy();
}
this._handle.close();
this._handle = null;
if (exitCode < 0) {
var syscall = this.spawnfile ? 'spawn ' + this.spawnfile : 'spawn';
const err = errnoException(exitCode, syscall);
if (this.spawnfile)
err.path = this.spawnfile;
err.spawnargs = this.spawnargs.slice(1);
this.emit('error', err);
} else {
this.emit('exit', this.exitCode, this.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(flushStdio, this);
maybeClose(this);
};
}
util.inherits(ChildProcess, EventEmitter);
function flushStdio(subprocess) {
const stdio = subprocess.stdio;
if (stdio == null) return;
for (var i = 0; i < stdio.length; i++) {
const stream = stdio[i];
if (!stream || !stream.readable || stream._readableState.readableListening)
continue;
stream.resume();
}
}
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;
}
function getHandleWrapType(stream) {
if (stream instanceof Pipe) return 'pipe';
if (stream instanceof TTY) return 'tty';
if (stream instanceof TCP) return 'tcp';
if (stream instanceof UDP) return 'udp';
return false;
}
ChildProcess.prototype.spawn = function(options) {
var ipc;
var ipcFd;
var i;
if (options === null || typeof options !== 'object')
throw new TypeError('"options" must be an object');
// If no `stdio` option was given - use default
var stdio = options.stdio || 'pipe';
stdio = _validateStdio(stdio, false);
ipc = stdio.ipc;
ipcFd = stdio.ipcFd;
stdio = options.stdio = stdio.stdio;
if (ipc !== undefined) {
// Let child process know about opened IPC channel
if (options.envPairs === undefined)
options.envPairs = [];
else if (!Array.isArray(options.envPairs))
throw new TypeError('"envPairs" must be an array');
options.envPairs.push('NODE_CHANNEL_FD=' + ipcFd);
}
if (typeof options.file === 'string')
this.spawnfile = options.file;
else
throw new TypeError('"file" must be a string');
if (Array.isArray(options.args))
this.spawnargs = options.args;
else if (options.args === undefined)
this.spawnargs = [];
else
throw new TypeError('"args" must be an array');
var err = this._handle.spawn(options);
// Run-time errors should emit an error, not throw an exception.
if (err === uv.UV_EAGAIN ||
err === uv.UV_EMFILE ||
err === uv.UV_ENFILE ||
err === uv.UV_ENOENT) {
process.nextTick(onErrorNT, this, err);
// There is no point in continuing when we've hit EMFILE or ENFILE
// because we won't be able to set up the stdio file descriptors.
// It's kind of silly that the de facto spec for ENOENT (the test suite)
// mandates that stdio _is_ set up, even if there is no process on the
// receiving end, but it is what it is.
if (err !== uv.UV_ENOENT) return err;
} else if (err) {
// Close all opened fds on error
for (i = 0; i < stdio.length; i++) {
const stream = stdio[i];
if (stream.type === 'pipe') {
stream.handle.close();
}
}
this._handle.close();
this._handle = null;
throw errnoException(err, 'spawn');
}
this.pid = this._handle.pid;
for (i = 0; i < stdio.length; i++) {
const stream = stdio[i];
if (stream.type === 'ignore') continue;
if (stream.ipc) {
this._closesNeeded++;
continue;
}
if (stream.handle) {
// when i === 0 - we're dealing with stdin
// (which is the only one writable pipe)
stream.socket = createSocket(this.pid !== 0 ?
stream.handle : null, i > 0);
if (i > 0 && this.pid !== 0) {
this._closesNeeded++;
stream.socket.on('close', () => {
maybeClose(this);
});
}
}
}
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 = [];
for (i = 0; i < stdio.length; i++)
this.stdio.push(stdio[i].socket === undefined ? null : stdio[i].socket);
// Add .send() method and start listening for IPC data
if (ipc !== undefined) setupChannel(this, ipc);
return err;
};
function onErrorNT(self, err) {
self._handle.onexit(err);
}
ChildProcess.prototype.kill = function(sig) {
const signal = sig === 0 ? sig :
convertToValidSignal(sig === undefined ? 'SIGTERM' : sig);
if (this._handle) {
var err = this._handle.kill(signal);
if (err === 0) {
/* Success. */
this.killed = true;
return true;
}
if (err === uv.UV_ESRCH) {
/* Already dead. */
} else if (err === uv.UV_EINVAL || err === uv.UV_ENOSYS) {
/* The underlying platform doesn't support this signal. */
throw errnoException(err, 'kill');
} else {
/* Other error, almost certainly EPERM. */
this.emit('error', errnoException(err, '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();
};
class Control extends EventEmitter {
constructor(channel) {
super();
this.channel = channel;
this.refs = 0;
}
ref() {
if (++this.refs === 1) {
this.channel.ref();
}
}
unref() {
if (--this.refs === 0) {
this.channel.unref();
this.emit('unref');
}
}
}
function setupChannel(target, channel) {
target.channel = channel;
// _channel can be deprecated in version 8
Object.defineProperty(target, '_channel', {
get() { return target.channel; },
set(val) { target.channel = val; },
enumerable: true
});
target._handleQueue = null;
target._pendingHandle = null;
const control = new Control(channel);
var decoder = new StringDecoder('utf8');
var jsonBuffer = '';
channel.buffering = false;
channel.onread = function(nread, pool, recvHandle) {
// TODO(bnoordhuis) Check that nread > 0.
if (pool) {
// Linebreak is used as a message end sign
var chunks = decoder.write(pool).split('\n');
var numCompleteChunks = chunks.length - 1;
// Last line does not have trailing linebreak
var incompleteChunk = chunks[numCompleteChunks];
if (numCompleteChunks === 0) {
jsonBuffer += incompleteChunk;
this.buffering = jsonBuffer.length !== 0;
return;
}
chunks[0] = jsonBuffer + chunks[0];
var nextTick = false;
for (var i = 0; i < numCompleteChunks; i++) {
var message = JSON.parse(chunks[i]);
// There will be at most one NODE_HANDLE message in every chunk we
// read because SCM_RIGHTS messages don't get coalesced. Make sure
// that we deliver the handle with the right message however.
if (isInternal(message)) {
if (message.cmd === 'NODE_HANDLE')
handleMessage(message, recvHandle, true, false);
else
handleMessage(message, undefined, true, false);
} else {
handleMessage(message, undefined, false, nextTick);
nextTick = true;
}
}
jsonBuffer = incompleteChunk;
this.buffering = jsonBuffer.length !== 0;
} else {
this.buffering = false;
target.disconnect();
channel.onread = nop;
channel.close();
target.channel = null;
maybeClose(target);
}
};
// object where socket lists will live
channel.sockets = { got: {}, send: {} };
// handlers will go through this
target.on('internalMessage', function(message, handle) {
// Once acknowledged - continue sending handles.
if (message.cmd === 'NODE_HANDLE_ACK') {
if (target._pendingHandle) {
target._pendingHandle.close();
target._pendingHandle = null;
}
assert(Array.isArray(target._handleQueue));
var queue = target._handleQueue;
target._handleQueue = null;
for (var i = 0; i < queue.length; i++) {
var args = queue[i];
target._send(args.message, args.handle, args.options, args.callback);
}
// Process a pending disconnect (if any).
if (!target.connected && target.channel && !target._handleQueue)
target._disconnect();
return;
}
if (message.cmd !== 'NODE_HANDLE') return;
// Acknowledge handle receival. Don't emit error events (for example if
// the other side has disconnected) because this call to send() is not
// initiated by the user and it shouldn't be fatal to be unable to ACK
// a message.
target._send({ cmd: 'NODE_HANDLE_ACK' }, null, true);
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(message.msg, handle, isInternal(message.msg), false);
});
});
target.send = function(message, handle, options, callback) {
if (typeof handle === 'function') {
callback = handle;
handle = undefined;
options = undefined;
} else if (typeof options === 'function') {
callback = options;
options = undefined;
} else if (options !== undefined &&
(options === null || typeof options !== 'object')) {
throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'options', 'Object');
}
options = Object.assign({swallowErrors: false}, options);
if (this.connected) {
return this._send(message, handle, options, callback);
}
const ex = new errors.Error('ERR_IPC_CHANNEL_CLOSED');
if (typeof callback === 'function') {
process.nextTick(callback, ex);
} else {
this.emit('error', ex); // FIXME(bnoordhuis) Defer to next tick.
}
return false;
};
target._send = function(message, handle, options, callback) {
assert(this.connected || this.channel);
if (message === undefined)
throw new errors.TypeError('ERR_MISSING_ARGS', 'message');
// Support legacy function signature
if (typeof options === 'boolean') {
options = {swallowErrors: options};
}
// package messages with a handle object
if (handle) {
// this message will be handled by an internalMessage event handler
message = {
cmd: 'NODE_HANDLE',
type: null,
msg: message
};
if (handle instanceof net.Socket) {
message.type = 'net.Socket';
} else if (handle instanceof net.Server) {
message.type = 'net.Server';
} else if (handle instanceof TCP || handle instanceof Pipe) {
message.type = 'net.Native';
} else if (handle instanceof dgram.Socket) {
message.type = 'dgram.Socket';
} else if (handle instanceof UDP) {
message.type = 'dgram.Native';
} else {
throw new errors.TypeError('ERR_INVALID_HANDLE_TYPE');
}
// Queue-up message and handle if we haven't received ACK yet.
if (this._handleQueue) {
this._handleQueue.push({
callback: callback,
handle: handle,
options: options,
message: message.msg,
});
return this._handleQueue.length === 1;
}
var obj = handleConversion[message.type];
// convert TCP object to native handle object
handle = handleConversion[message.type].send.call(target,
message,
handle,
options);
// If handle was sent twice, or it is impossible to get native handle
// out of it - just send a text without the handle.
if (!handle)
message = message.msg;
// Update simultaneous accepts on Windows
if (obj.simultaneousAccepts) {
net._setSimultaneousAccepts(handle);
}
} else if (this._handleQueue &&
!(message && message.cmd === 'NODE_HANDLE_ACK')) {
// Queue request anyway to avoid out-of-order messages.
this._handleQueue.push({
callback: callback,
handle: null,
options: options,
message: message,
});
return this._handleQueue.length === 1;
}
var req = new WriteWrap();
req.async = false;
var string = JSON.stringify(message) + '\n';
var err = channel.writeUtf8String(req, string, handle);
if (err === 0) {
if (handle) {
if (!this._handleQueue)
this._handleQueue = [];
if (obj && obj.postSend)
obj.postSend(handle, options, target);
}
if (req.async) {
req.oncomplete = function() {
control.unref();
if (typeof callback === 'function')
callback(null);
};
control.ref();
} else if (typeof callback === 'function') {
process.nextTick(callback, null);
}
} else {
// Cleanup handle on error
if (obj && obj.postSend)
obj.postSend(handle, options);
if (!options.swallowErrors) {
const ex = errnoException(err, 'write');
if (typeof callback === 'function') {
process.nextTick(callback, ex);
} else {
this.emit('error', ex); // FIXME(bnoordhuis) Defer to next tick.
}
}
}
/* If the master is > 2 read() calls behind, please stop sending. */
return channel.writeQueueSize < (65536 * 2);
};
// connected will be set to false immediately when a disconnect() is
// requested, even though the channel might still be alive internally to
// process queued messages. The three states are distinguished as follows:
// - disconnect() never requested: channel is not null and connected
// is true
// - disconnect() requested, messages in the queue: channel is not null
// and connected is false
// - disconnect() requested, channel actually disconnected: channel is
// null and connected is false
target.connected = true;
target.disconnect = function() {
if (!this.connected) {
this.emit('error', new errors.Error('ERR_IPC_DISCONNECTED'));
return;
}
// Do not allow any new messages to be written.
this.connected = false;
// If there are no queued messages, disconnect immediately. Otherwise,
// postpone the disconnect so that it happens internally after the
// queue is flushed.
if (!this._handleQueue)
this._disconnect();
};
target._disconnect = function() {
assert(this.channel);
// This marks the fact that the channel is actually disconnected.
this.channel = null;
if (this._pendingHandle) {
this._pendingHandle.close();
this._pendingHandle = 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;
}
process.nextTick(finish);
};
function emit(event, message, handle) {
target.emit(event, message, handle);
}
function handleMessage(message, handle, internal, nextTick) {
if (!target.channel)
return;
var eventName = (internal ? 'internalMessage' : 'message');
if (nextTick)
process.nextTick(emit, eventName, message, handle);
else
target.emit(eventName, message, handle);
}
channel.readStart();
return control;
}
const INTERNAL_PREFIX = 'NODE_';
function isInternal(message) {
return (message !== null &&
typeof message === 'object' &&
typeof message.cmd === 'string' &&
message.cmd.length > INTERNAL_PREFIX.length &&
message.cmd.slice(0, INTERNAL_PREFIX.length) === INTERNAL_PREFIX);
}
function nop() { }
function _validateStdio(stdio, sync) {
var ipc;
var ipcFd;
// 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 errors.TypeError('ERR_INVALID_OPT_VALUE', 'stdio', stdio);
}
} else if (!Array.isArray(stdio)) {
throw new errors.TypeError('ERR_INVALID_OPT_VALUE',
'stdio', util.inspect(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() {
for (var i = 0; i < acc.length; i++) {
if ((acc[i].type === 'pipe' || acc[i].type === 'ipc') && acc[i].handle)
acc[i].handle.close();
}
}
// Defaults
if (stdio == null) {
stdio = i < 3 ? 'pipe' : 'ignore';
}
if (stdio === 'ignore') {
acc.push({type: 'ignore'});
} else if (stdio === 'pipe' || typeof stdio === 'number' && stdio < 0) {
var a = {
type: 'pipe',
readable: i === 0,
writable: i !== 0
};
if (!sync)
a.handle = new Pipe();
acc.push(a);
} else if (stdio === 'ipc') {
if (sync || ipc !== undefined) {
// Cleanup previously created pipes
cleanup();
if (!sync)
throw new errors.Error('ERR_IPC_ONE_PIPE');
else
throw new errors.Error('ERR_IPC_SYNC_FORK');
}
ipc = new Pipe(true);
ipcFd = i;
acc.push({
type: 'pipe',
handle: ipc,
ipc: true
});
} else if (stdio === 'inherit') {
acc.push({
type: 'inherit',
fd: i
});
} else if (typeof stdio === 'number' || typeof stdio.fd === 'number') {
acc.push({
type: 'fd',
fd: typeof stdio === 'number' ? stdio : stdio.fd
});
} 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 if (isUint8Array(stdio) || typeof stdio === 'string') {
if (!sync) {
cleanup();
throw new errors.TypeError('ERR_INVALID_SYNC_FORK_INPUT',
util.inspect(stdio));
}
} else {
// Cleanup
cleanup();
throw new errors.TypeError('ERR_INVALID_OPT_VALUE', 'stdio',
util.inspect(stdio));
}
return acc;
}, []);
return { stdio, ipc, ipcFd };
}
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 maybeClose(subprocess) {
subprocess._closesGot++;
if (subprocess._closesGot === subprocess._closesNeeded) {
subprocess.emit('close', subprocess.exitCode, subprocess.signalCode);
}
}
function spawnSync(opts) {
var options = opts.options;
var result = spawn_sync.spawn(options);
if (result.output && options.encoding && options.encoding !== 'buffer') {
for (var i = 0; i < result.output.length; i++) {
if (!result.output[i])
continue;
result.output[i] = result.output[i].toString(options.encoding);
}
}
result.stdout = result.output && result.output[1];
result.stderr = result.output && result.output[2];
if (result.error) {
result.error = errnoException(result.error, 'spawnSync ' + opts.file);
result.error.path = opts.file;
result.error.spawnargs = opts.args.slice(1);
}
return result;
}
module.exports = {
ChildProcess,
setupChannel,
_validateStdio,
getSocketList,
spawnSync
};