Better use a wrapper

boot.php

@@ -1399,7 +1399,7 @@ function get_temppath() {
 
 	if (($temppath != "") && App::directory_usable($temppath)) {
 		// We have a temp path and it is usable
-		return realpath($temppath);
+		return App::realpath($temppath);
 	}
 
 	// We don't have a working preconfigured temp path, so we take the system path.
@@ -1408,7 +1408,7 @@ function get_temppath() {
 	// Check if it is usable
 	if (($temppath != "") && App::directory_usable($temppath)) {
 		// Always store the real path, not the path through symlinks
-		$temppath = realpath($temppath);
+		$temppath = App::realpath($temppath);
 
 		// To avoid any interferences with other systems we create our own directory
 		$new_temppath = $temppath . "/" . $a->get_hostname();
@@ -1498,7 +1498,7 @@ function get_itemcachepath() {
 
 	$itemcache = get_config('system', 'itemcache');
 	if (($itemcache != "") && App::directory_usable($itemcache)) {
-		return realpath($itemcache);
+		return App::realpath($itemcache);
 	}
 
 	$temppath = get_temppath();

mod/admin.php

@@ -975,7 +975,7 @@ function admin_page_site_post(App $a) {
 	set_config('system', 'hide_help', $hide_help);
 
 	if ($itemcache != '') {
-		$itemcache = realpath($itemcache);
+		$itemcache = App::realpath($itemcache);
 	}
 
 	set_config('system', 'itemcache', $itemcache);
@@ -983,13 +983,13 @@ function admin_page_site_post(App $a) {
 	set_config('system', 'max_comments', $max_comments);
 
 	if ($temppath != '') {
-		$temppath = realpath($temppath);
+		$temppath = App::realpath($temppath);
 	}
 
 	set_config('system', 'temppath', $temppath);
 
 	if ($basepath != '') {
-		$basepath = realpath($basepath);
+		$basepath = App::realpath($basepath);
 	}
 
 	set_config('system', 'basepath', $basepath);

src/App.php

@@ -327,7 +327,27 @@ class App {
 			$basepath = $_SERVER['PWD'];
 		}
 
-		return $basepath;
+		return self::realpath($basepath);
+	}
+
+	/**
+	 * @brief Returns a normalized file path
+	 *
+	 * This is a wrapper for the "realpath" function.
+	 * That function cannot detect the real path when some folders aren't readable.
+	 * Since this could happen with some hosters we need to handle this.
+	 *
+	 * @param string $path The path that is about to be normalized
+	 * @return string normalized path - when possible
+	 */
+	public static function realpath($path) {
+		$normalized = realpath($path);
+
+		if (!is_bool($normalized)) {
+			return $normalized;
+		} else {
+			return $path;
+		}
 	}
 
 	function get_scheme() {