[stable26] Detect aborted connection in OC\Files\View and stop writing data to the output buffer

lib/composer/composer/autoload_classmap.php

@@ -271,6 +271,7 @@
     'OCP\\Files\\Config\\IMountProviderCollection' => $baseDir . '/lib/public/Files/Config/IMountProviderCollection.php',
     'OCP\\Files\\Config\\IRootMountProvider' => $baseDir . '/lib/public/Files/Config/IRootMountProvider.php',
     'OCP\\Files\\Config\\IUserMountCache' => $baseDir . '/lib/public/Files/Config/IUserMountCache.php',
+    'OCP\\Files\\ConnectionLostException' => $baseDir . '/lib/public/Files/ConnectionLostException.php',
     'OCP\\Files\\DavUtil' => $baseDir . '/lib/public/Files/DavUtil.php',
     'OCP\\Files\\EmptyFileNameException' => $baseDir . '/lib/public/Files/EmptyFileNameException.php',
     'OCP\\Files\\EntityTooLargeException' => $baseDir . '/lib/public/Files/EntityTooLargeException.php',

lib/composer/composer/autoload_static.php

@@ -304,6 +304,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Files\\Config\\IMountProviderCollection' => __DIR__ . '/../../..' . '/lib/public/Files/Config/IMountProviderCollection.php',
         'OCP\\Files\\Config\\IRootMountProvider' => __DIR__ . '/../../..' . '/lib/public/Files/Config/IRootMountProvider.php',
         'OCP\\Files\\Config\\IUserMountCache' => __DIR__ . '/../../..' . '/lib/public/Files/Config/IUserMountCache.php',
+        'OCP\\Files\\ConnectionLostException' => __DIR__ . '/../../..' . '/lib/public/Files/ConnectionLostException.php',
         'OCP\\Files\\DavUtil' => __DIR__ . '/../../..' . '/lib/public/Files/DavUtil.php',
         'OCP\\Files\\EmptyFileNameException' => __DIR__ . '/../../..' . '/lib/public/Files/EmptyFileNameException.php',
         'OCP\\Files\\EntityTooLargeException' => __DIR__ . '/../../..' . '/lib/public/Files/EntityTooLargeException.php',

lib/private/Files/View.php

@@ -55,6 +55,7 @@
 use OCA\Files_Sharing\SharedMount;
 use OCP\Constants;
 use OCP\Files\Cache\ICacheEntry;
+use OCP\Files\ConnectionLostException;
 use OCP\Files\EmptyFileNameException;
 use OCP\Files\FileNameTooLongException;
 use OCP\Files\InvalidCharacterInPathException;
@@ -427,10 +428,11 @@ public function readfile($path) {
 		}
 		$handle = $this->fopen($path, 'rb');
 		if ($handle) {
-			$chunkSize = 524288; // 512 kB chunks
+			$chunkSize = 524288; // 512 kiB chunks
 			while (!feof($handle)) {
 				echo fread($handle, $chunkSize);
 				flush();
+				$this->checkConnectionStatus();
 			}
 			fclose($handle);
 			return $this->filesize($path);
@@ -483,6 +485,7 @@ public function readfilePart($path, $from, $to) {
 					}
 					echo fread($handle, $len);
 					flush();
+					$this->checkConnectionStatus();
 				}
 				return ftell($handle) - $from;
 			}
@@ -492,6 +495,14 @@ public function readfilePart($path, $from, $to) {
 		return false;
 	}
 
+
+	private function checkConnectionStatus(): void {
+		$connectionStatus = \connection_status();
+		if ($connectionStatus !== CONNECTION_NORMAL) {
+			throw new ConnectionLostException("Connection lost. Status: $connectionStatus");
+		}
+	}
+
 	/**
 	 * @param string $path
 	 * @return mixed

lib/private/legacy/OC_Files.php

@@ -230,14 +230,15 @@ public static function get($dir, $files, $params = null) {
 			OC::$server->getLogger()->logException($ex);
 			$l = \OC::$server->getL10N('lib');
 			\OC_Template::printErrorPage($l->t('Cannot download file'), $ex->getMessage(), 200);
+		} catch (\OCP\Files\ConnectionLostException $ex) {
+			self::unlockAllTheFiles($dir, $files, $getType, $view, $filename);
+			OC::$server->getLogger()->logException($ex, ['level' => \OCP\ILogger::DEBUG]);
+			\OC_Template::printErrorPage('Connection lost', $ex->getMessage(), 200);
 		} catch (\Exception $ex) {
 			self::unlockAllTheFiles($dir, $files, $getType, $view, $filename);
 			OC::$server->getLogger()->logException($ex);
 			$l = \OC::$server->getL10N('lib');
 			$hint = method_exists($ex, 'getHint') ? $ex->getHint() : '';
-			if ($event && $event->getErrorMessage() !== null) {
-				$hint .= ' ' . $event->getErrorMessage();
-			}
 			\OC_Template::printErrorPage($l->t('Cannot download file'), $hint, 200);
 		}
 	}

lib/public/Files/ConnectionLostException.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ *
+ * @author Côme Chilliet <come.chilliet@nextcloud.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCP\Files;
+
+/**
+ * Exception for lost connection with the
+ * @since 25.0.11
+ */
+class ConnectionLostException extends \RuntimeException {
+}