From 8b98096c921f8a210b05aed64e0b2f1440667a7c Mon Sep 17 00:00:00 2001
From: Jackson Tian <puling.tyq@alibaba-inc.com>
Date: Mon, 19 Jan 2015 18:12:16 +0800
Subject: [PATCH] fs: make fs.access() flags read only

These flags were defined as constants, but could be
overwritten when exported from fs. This commit exports
the flags as read only properties of fs.

PR-URL: https://github.com/iojs/io.js/pull/507
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 lib/fs.js | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/lib/fs.js b/lib/fs.js
index 726d5065412e0a..5466ab9cadbd64 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -27,10 +27,6 @@ const O_RDWR = constants.O_RDWR || 0;
 const O_SYNC = constants.O_SYNC || 0;
 const O_TRUNC = constants.O_TRUNC || 0;
 const O_WRONLY = constants.O_WRONLY || 0;
-const F_OK = constants.F_OK || 0;
-const R_OK = constants.R_OK || 0;
-const W_OK = constants.W_OK || 0;
-const X_OK = constants.X_OK || 0;
 
 const isWindows = process.platform === 'win32';
 
@@ -164,10 +160,12 @@ fs.Stats.prototype.isSocket = function() {
   return this._checkModeProperty(constants.S_IFSOCK);
 };
 
-fs.F_OK = F_OK;
-fs.R_OK = R_OK;
-fs.W_OK = W_OK;
-fs.X_OK = X_OK;
+// Don't allow mode to accidentally be overwritten.
+['F_OK', 'R_OK', 'W_OK', 'X_OK'].forEach(function(key) {
+  Object.defineProperty(fs, key, {
+    enumerable: true, value: constants[key] || 0, writable: false
+  });
+});
 
 fs.access = function(path, mode, callback) {
   if (!nullCheck(path, callback))
@@ -175,7 +173,7 @@ fs.access = function(path, mode, callback) {
 
   if (typeof mode === 'function') {
     callback = mode;
-    mode = F_OK;
+    mode = fs.F_OK;
   } else if (typeof callback !== 'function') {
     throw new TypeError('callback must be a function');
   }
@@ -190,7 +188,7 @@ fs.accessSync = function(path, mode) {
   nullCheck(path);
 
   if (mode === undefined)
-    mode = F_OK;
+    mode = fs.F_OK;
   else
     mode = mode | 0;