From e1a72f0e2e4fa668d73657c55ed399f674af6ec0 Mon Sep 17 00:00:00 2001
From: isaacs <i@izs.me>
Date: Tue, 29 Mar 2011 14:54:49 -0700
Subject: [PATCH] Closes GH-535 Immediate pause/resume race condition

Calling resume() immediately after calling pause() would trigger
a race condition where it would try to read() from a file
descriptor that was already being read from, causing an EBADF
---
 lib/fs.js                          | 5 ++++-
 test/simple/test-fs-read-stream.js | 7 ++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/fs.js b/lib/fs.js
index 5329290f2a0..0f2318d5845 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -838,7 +838,9 @@ ReadStream.prototype.setEncoding = function(encoding) {
 
 ReadStream.prototype._read = function() {
   var self = this;
-  if (!self.readable || self.paused) return;
+  if (!self.readable || self.paused || self.reading) return;
+
+  self.reading = true;
 
   if (!pool || pool.length - pool.used < kMinPoolSpace) {
     // discard the old pool. Can't add to the free list because
@@ -864,6 +866,7 @@ ReadStream.prototype._read = function() {
   }
 
   function afterRead(err, bytesRead) {
+    self.reading = false;
     if (err) {
       self.emit('error', err);
       self.readable = false;
diff --git a/test/simple/test-fs-read-stream.js b/test/simple/test-fs-read-stream.js
index 8b821c01d8f..188c95d52db 100644
--- a/test/simple/test-fs-read-stream.js
+++ b/test/simple/test-fs-read-stream.js
@@ -42,8 +42,13 @@ file.addListener('open', function(fd) {
   callbacks.open++;
   assert.equal('number', typeof fd);
   assert.ok(file.readable);
-});
 
+  // GH-535
+  file.pause();
+  file.resume();
+  file.pause();
+  file.resume();
+});
 
 file.addListener('data', function(data) {
   assert.ok(data instanceof Buffer);