PDFBOX-6185: warn if permission setting didn't work

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1932730 13f79535-47bb-0310-9956-ffa450edef68

Author: Maruan Sahyoun

io/src/main/java/org/apache/pdfbox/io/IOUtils.java

@@ -384,9 +384,15 @@ private static void applyOwnerOnlyPermissions(Path dir) throws IOException
             if (aclView == null)
             {
                 File tempDir = dir.toFile();
-                tempDir.setReadable(true, true);
-                tempDir.setWritable(true, true);
-                tempDir.setExecutable(true, true);
+                boolean isReadable = tempDir.setReadable(true, true);
+                boolean isWritable = tempDir.setWritable(true, true);
+                boolean isExecutable = tempDir.setExecutable(true, true);
+                if (!isReadable || !isWritable || !isExecutable)
+                {
+                    LOG.warn("Unable to set owner-only permissions on temporary directory: {}. " +
+                            "Please ensure that the temporary directory is protected against unauthorized access.",
+                            dir);
+                }
                 return;
             }