From f25a807da3be09beff4d6fdca1e700242b33779c Mon Sep 17 00:00:00 2001
From: Sujith H <sharidasan@owncloud.com>
Date: Mon, 12 Feb 2018 20:52:34 +0530
Subject: [PATCH] [stable10] Check exec and stat method before using it

Before using exec and stat method in 32 bit
machines, a check is required if they are
available or not. Else fallback to the
filemtime(path);

Signed-off-by: Sujith H <sharidasan@owncloud.com>
---
 lib/private/Files/Storage/Local.php | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/lib/private/Files/Storage/Local.php b/lib/private/Files/Storage/Local.php
index 5c278de6b410..44a67d7238a2 100644
--- a/lib/private/Files/Storage/Local.php
+++ b/lib/private/Files/Storage/Local.php
@@ -180,12 +180,26 @@ public function filemtime($path) {
 			return false;
 		}
 		if (PHP_INT_SIZE === 4) {
-			if (\OC_Util::runningOn('linux')) {
-				return (int) exec ('stat -c %Y '. escapeshellarg ($fullPath));
-			} else if (\OC_Util::runningOn('bsd') || \OC_Util::runningOn('mac')) {
-				return (int) exec ('stat -f %m '. escapeshellarg ($fullPath));
+			/**
+			 * Check if exec is available to use before calling it.
+			 */
+			if (function_exists('exec') === true) {
+				$result = 0;
+				$returnVar = 0;
+				if (\OC_Util::runningOn('linux')) {
+					$result = (int)exec('stat -c %Y ' . escapeshellarg($fullPath), $output, $returnVar);
+				} else if (\OC_Util::runningOn('bsd') || \OC_Util::runningOn('mac')) {
+					$result = (int)exec('stat -f %m ' . escapeshellarg($fullPath), $output, $returnVar);
+				}
+
+				/**
+				 * If the result is zero, then stat is missing.
+				 * Additionally check the return status from the shell.
+				 */
+				if ($returnVar === 0) {
+					return $result;
+				}
 			}
-			return false;
 		}
 		return filemtime($fullPath);
 	}