improve timezone detection

src/System.php

@@ -16,6 +16,8 @@ class System {
 
 	private $stdbuf;
 
+	private $date;
+
 	public static function getFD($num) {
 		$folders = [
 			'/proc/self/fd',
@@ -43,6 +45,13 @@ class System {
 		return $this->net;
 	}
 
+	public function getDatePath() {
+		if (!$this->date) {
+			$this->date = trim(`which date`);
+		}
+		return $this->date;
+	}
+
 	public function hasStdBuf() {
 		if (!$this->stdbuf) {
 			$result = null;

src/TimeZoneProvider.php

@@ -41,8 +41,14 @@ class TimeZoneProvider {
 					escapeshellarg($this->host)
 				);
 				$this->timeZone = exec($command);
-			} else { // fallback to server timezone
+			}
-				$this->timeZone = date_default_timezone_get();
+			if (!$this->timeZone) { // fallback to server timezone
+				$date = $this->system->getDatePath();
+				if ($date) {
+					$this->timeZone = exec($date . " +%z");
+				} else {
+					$this->timeZone = date_default_timezone_get();
+				}
 			}
 		}
 		return $this->timeZone;

tests/TimeZoneProviderTest.php

@@ -0,0 +1,72 @@
+<?php declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019 Robin Appelman <robin@icewind.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Icewind\SMB\Test;
+
+use Icewind\SMB\System;
+use Icewind\SMB\TimeZoneProvider;
+
+class TimeZoneProviderTest extends TestCase {
+	/** @var System|\PHPUnit_Framework_MockObject_MockObject */
+	private $system;
+	/** @var TimeZoneProvider */
+	private $provider;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->system = $this->createMock(System::class);
+	}
+
+	private function getDummyCommand($output) {
+		return "echo '$output' || false";
+	}
+
+	public function testFQDN() {
+		$this->system->method('getNetPath')
+			->willReturn($this->getDummyCommand("+800"));
+		$this->system->method('getDatePath')
+			->willReturn($this->getDummyCommand("+700"));
+		$this->provider = new TimeZoneProvider('foo.bar.com', $this->system);
+
+		$this->assertEquals('+800', $this->provider->get());
+	}
+
+	public function testNoNet() {
+		$this->system->method('getNetPath')
+			->willReturn(false);
+		$this->system->method('getDatePath')
+			->willReturn($this->getDummyCommand("+700"));
+		$this->provider = new TimeZoneProvider('foo.bar.com', $this->system);
+
+		$this->assertEquals('+700', $this->provider->get());
+	}
+
+	public function testNoNetNoDate() {
+		$this->system->method('getNetPath')
+			->willReturn(false);
+		$this->system->method('getDatePath')
+			->willReturn(false);
+		$this->provider = new TimeZoneProvider('foo.bar.com', $this->system);
+
+		$this->assertEquals(date_default_timezone_get(), $this->provider->get());
+	}
+}