cluster: add cwd to cluster.settings

This commit allows cluster workers to be created with
configurable working directories.

Fixes: nodejs#16388
PR-URL: nodejs#18399
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/cluster.md

@@ -711,6 +711,8 @@ changes:
   * `exec` {string} File path to worker file. **Default:** `process.argv[1]`
   * `args` {Array} String arguments passed to worker.
     **Default:** `process.argv.slice(2)`
+  * `cwd` {string} Current working directory of the worker process. **Default:**
+    `undefined` (inherits from parent process)
   * `silent` {boolean} Whether or not to send output to parent's stdio.
     **Default:** `false`
   * `stdio` {Array} Configures the stdio of forked processes. Because the

lib/internal/cluster/master.js

@@ -126,6 +126,7 @@ function createWorkerProcess(id, env) {
   }
 
   return fork(cluster.settings.exec, cluster.settings.args, {
+    cwd: cluster.settings.cwd,
     env: workerEnv,
     silent: cluster.settings.silent,
     windowsHide: cluster.settings.windowsHide,

test/parallel/test-cluster-cwd.js

@@ -0,0 +1,22 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+
+if (cluster.isMaster) {
+  common.refreshTmpDir();
+
+  assert.strictEqual(cluster.settings.cwd, undefined);
+  cluster.fork().on('message', common.mustCall((msg) => {
+    assert.strictEqual(msg, process.cwd());
+  }));
+
+  cluster.setupMaster({ cwd: common.tmpDir });
+  assert.strictEqual(cluster.settings.cwd, common.tmpDir);
+  cluster.fork().on('message', common.mustCall((msg) => {
+    assert.strictEqual(msg, common.tmpDir);
+  }));
+} else {
+  process.send(process.cwd());
+  process.disconnect();
+}