src: tolerate EPERM returned from tcsetattr

macOS app sandbox makes tcsetattr return EPERM. The CHECK_EQ(0, err)
here would fail when a sandboxed Node.js process is exiting. This commit
fixes this issue.

* test: add test for running in macOS app sandbox

Bare-bone command-line executables cannot run directly in the app sandbox.
To test that Node.js is able to run in the sandbox (and to test the fix in
317621b), this commit creates a typical
Cocoa app bundle, puts the node executable in it and calles Apple's codesign
command to enable sandbox.

* test: use process.execPath to get path of testing node

PR-URL: #33944
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node.cc

@@ -737,7 +737,10 @@ void ResetStdio() {
         err = tcsetattr(fd, TCSANOW, &s.termios);
       while (err == -1 && errno == EINTR);  // NOLINT
       CHECK_EQ(0, pthread_sigmask(SIG_UNBLOCK, &sa, nullptr));
-      CHECK_EQ(0, err);
+
+      // Normally we expect err == 0. But if macOS App Sandbox is enabled,
+      // tcsetattr will fail with err == -1 and errno == EPERM.
+      CHECK_IMPLIES(err != 0, err == -1 && errno == EPERM);
     }
   }
 #endif  // __POSIX__

test/fixtures/macos-app-sandbox/Info.plist

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleExecutable</key>
+	<string>node</string>
+	<key>CFBundleIdentifier</key>
+	<string>org.nodejs.test.node_sandboxed</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>node_sandboxed</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleSupportedPlatforms</key>
+	<array>
+		<string>MacOSX</string>
+	</array>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+</dict>
+</plist>

test/fixtures/macos-app-sandbox/node_sandboxed.entitlements

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+</dict>
+</plist>

test/parallel/test-macos-app-sandbox.js

@@ -0,0 +1,65 @@
+'use strict';
+const common = require('../common');
+if (process.platform !== 'darwin')
+  common.skip('App Sandbox is only avaliable on Darwin');
+
+const fixtures = require('../common/fixtures');
+const tmpdir = require('../common/tmpdir');
+const assert = require('assert');
+const child_process = require('child_process');
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+const nodeBinary = process.execPath;
+
+tmpdir.refresh();
+
+const appBundlePath = path.join(tmpdir.path, 'node_sandboxed.app');
+const appBundleContentPath = path.join(appBundlePath, 'Contents');
+const appExecutablePath = path.join(
+  appBundleContentPath, 'MacOS', 'node');
+
+// Construct the app bundle and put the node executable in it:
+// node_sandboxed.app/
+// └── Contents
+//     ├── Info.plist
+//     ├── MacOS
+//     │   └── node
+fs.mkdirSync(appBundlePath);
+fs.mkdirSync(appBundleContentPath);
+fs.mkdirSync(path.join(appBundleContentPath, 'MacOS'));
+fs.copyFileSync(
+  fixtures.path('macos-app-sandbox', 'Info.plist'),
+  path.join(appBundleContentPath, 'Info.plist'));
+fs.copyFileSync(
+  nodeBinary,
+  appExecutablePath);
+
+
+// Sign the app bundle with sandbox entitlements:
+assert.strictEqual(
+  child_process.spawnSync('/usr/bin/codesign', [
+    '--entitlements', fixtures.path(
+      'macos-app-sandbox', 'node_sandboxed.entitlements'),
+    '-s', '-',
+    appBundlePath
+  ]).status,
+  0);
+
+// Sandboxed app shouldn't be able to read the home dir
+assert.notStrictEqual(
+  child_process.spawnSync(appExecutablePath, [
+    '-e', 'fs.readdirSync(process.argv[1])', os.homedir()
+  ]).status,
+  0);
+
+if (process.stdin.isTTY) {
+  // Run the sandboxed node instance with inherited tty stdin
+  const spawnResult = child_process.spawnSync(
+    appExecutablePath, ['-e', ''],
+    { stdio: 'inherit' }
+  );
+
+  assert.strictEqual(spawnResult.signal, null);
+}