| // Licensed to the Software Freedom Conservancy (SFC) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The SFC licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License. |
| |
| 'use strict'; |
| |
| var exec = require('child_process').exec, |
| fs = require('fs'), |
| net = require('net'); |
| |
| |
| /** |
| * The IANA suggested ephemeral port range. |
| * @type {{min: number, max: number}} |
| * @const |
| * @see http://en.wikipedia.org/wiki/Ephemeral_ports |
| */ |
| const DEFAULT_IANA_RANGE = {min: 49152, max: 65535}; |
| |
| |
| /** |
| * The epheremal port range for the current system. Lazily computed on first |
| * access. |
| * @type {Promise.<{min: number, max: number}>} |
| */ |
| var systemRange = null; |
| |
| |
| /** |
| * Computes the ephemeral port range for the current system. This is based on |
| * http://stackoverflow.com/a/924337. |
| * @return {!Promise<{min: number, max: number}>} A promise that will resolve to |
| * the ephemeral port range of the current system. |
| */ |
| function findSystemPortRange() { |
| if (systemRange) { |
| return systemRange; |
| } |
| var range = process.platform === 'win32' ? |
| findWindowsPortRange() : findUnixPortRange(); |
| return systemRange = range.catch(function() { |
| return DEFAULT_IANA_RANGE; |
| }); |
| } |
| |
| |
| /** |
| * Executes a command and returns its output if it succeeds. |
| * @param {string} cmd The command to execute. |
| * @return {!Promise<string>} A promise that will resolve with the command's |
| * stdout data. |
| */ |
| function execute(cmd) { |
| return new Promise((resolve, reject) => { |
| exec(cmd, function(err, stdout) { |
| if (err) { |
| reject(err); |
| } else { |
| resolve(stdout); |
| } |
| }); |
| }); |
| } |
| |
| |
| /** |
| * Computes the ephemeral port range for a Unix-like system. |
| * @return {!Promise<{min: number, max: number}>} A promise that will resolve |
| * with the ephemeral port range on the current system. |
| */ |
| function findUnixPortRange() { |
| var cmd; |
| if (process.platform === 'sunos') { |
| cmd = |
| '/usr/sbin/ndd /dev/tcp tcp_smallest_anon_port tcp_largest_anon_port'; |
| } else if (fs.existsSync('/proc/sys/net/ipv4/ip_local_port_range')) { |
| // Linux |
| cmd = 'cat /proc/sys/net/ipv4/ip_local_port_range'; |
| } else { |
| cmd = 'sysctl net.inet.ip.portrange.first net.inet.ip.portrange.last' + |
| ' | sed -e "s/.*:\\s*//"'; |
| } |
| |
| return execute(cmd).then(function(stdout) { |
| if (!stdout || !stdout.length) return DEFAULT_IANA_RANGE; |
| var range = stdout.trim().split(/\s+/).map(Number); |
| if (range.some(isNaN)) return DEFAULT_IANA_RANGE; |
| return {min: range[0], max: range[1]}; |
| }); |
| } |
| |
| |
| /** |
| * Computes the ephemeral port range for a Windows system. |
| * @return {!Promise<{min: number, max: number}>} A promise that will resolve |
| * with the ephemeral port range on the current system. |
| */ |
| function findWindowsPortRange() { |
| // First, check if we're running on XP. If this initial command fails, |
| // we just fallback on the default IANA range. |
| return execute('cmd.exe /c ver').then(function(stdout) { |
| if (/Windows XP/.test(stdout)) { |
| // TODO: Try to read these values from the registry. |
| return {min: 1025, max: 5000}; |
| } else { |
| return execute('netsh int ipv4 show dynamicport tcp'). |
| then(function(stdout) { |
| /* > netsh int ipv4 show dynamicport tcp |
| Protocol tcp Dynamic Port Range |
| --------------------------------- |
| Start Port : 49152 |
| Number of Ports : 16384 |
| */ |
| var range = stdout.split(/\n/).filter(function(line) { |
| return /.*:\s*\d+/.test(line); |
| }).map(function(line) { |
| return Number(line.split(/:\s*/)[1]); |
| }); |
| |
| return { |
| min: range[0], |
| max: range[0] + range[1] |
| }; |
| }); |
| } |
| }); |
| } |
| |
| |
| /** |
| * Tests if a port is free. |
| * @param {number} port The port to test. |
| * @param {string=} opt_host The bound host to test the {@code port} against. |
| * Defaults to {@code INADDR_ANY}. |
| * @return {!Promise<boolean>} A promise that will resolve with whether the port |
| * is free. |
| */ |
| function isFree(port, opt_host) { |
| return new Promise((resolve, reject) => { |
| let server = net.createServer().on('error', function(e) { |
| if (e.code === 'EADDRINUSE') { |
| resolve(false); |
| } else { |
| reject(e); |
| } |
| }); |
| |
| server.listen(port, opt_host, function() { |
| server.close(() => resolve(true)); |
| }); |
| }); |
| } |
| |
| |
| /** |
| * @param {string=} opt_host The bound host to test the {@code port} against. |
| * Defaults to {@code INADDR_ANY}. |
| * @return {!Promise<number>} A promise that will resolve to a free port. If a |
| * port cannot be found, the promise will be rejected. |
| */ |
| function findFreePort(opt_host) { |
| return findSystemPortRange().then(function(range) { |
| var attempts = 0; |
| return new Promise((resolve, reject) => { |
| findPort(); |
| |
| function findPort() { |
| attempts += 1; |
| if (attempts > 10) { |
| reject(Error('Unable to find a free port')); |
| } |
| |
| var port = Math.floor( |
| Math.random() * (range.max - range.min) + range.min); |
| isFree(port, opt_host).then(function(isFree) { |
| if (isFree) { |
| resolve(port); |
| } else { |
| findPort(); |
| } |
| }, findPort); |
| } |
| }); |
| }); |
| } |
| |
| |
| // PUBLIC API |
| |
| |
| exports.findFreePort = findFreePort; |
| exports.isFree = isFree; |