From 38ea1419f60d2b8176dba4931748f1f0e52ca84e Mon Sep 17 00:00:00 2001
From: Jason Lowe <jlowe@apache.org>
Date: Mon, 1 Dec 2014 22:29:05 +0000
Subject: [PATCH] YARN-2905. AggregatedLogsBlock page can infinitely loop if
 the aggregated log file is corrupted. Contributed by Varun Saxena (cherry
 picked from commit 0f9528b99addbb0fd9a19d84db22a8c8e934b05f)

---
 hadoop-yarn-project/CHANGES.txt                        |  3 +++
 .../yarn/logaggregation/AggregatedLogFormat.java       |  4 ++++
 .../hadoop/yarn/webapp/log/AggregatedLogsBlock.java    | 10 ++++++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index f9ec5eda4b5..a570a0ffde4 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -128,6 +128,9 @@ Release 2.7.0 - UNRELEASED
     YARN-2906. CapacitySchedulerPage shows HTML tags for a queue's Active Users.
     (Jason Lowe via jianhe)
 
+    YARN-2905. AggregatedLogsBlock page can infinitely loop if the aggregated
+    log file is corrupted (Varun Saxena via jlowe)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/logaggregation/AggregatedLogFormat.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/logaggregation/AggregatedLogFormat.java
index a434ef59a6d..7eebcb334ff 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/logaggregation/AggregatedLogFormat.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/logaggregation/AggregatedLogFormat.java
@@ -801,6 +801,10 @@ public class AggregatedLogFormat {
       return currentLogData.skip(n);
     }
 
+    public int read() throws IOException {
+      return currentLogData.read();
+    }
+
     public int read(byte[] buf, int off, int len) throws IOException {
       return currentLogData.read(buf, off, len);
     }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/log/AggregatedLogsBlock.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/log/AggregatedLogsBlock.java
index 3e9f7a24758..620d097bdb5 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/log/AggregatedLogsBlock.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/log/AggregatedLogsBlock.java
@@ -231,8 +231,14 @@ public class AggregatedLogsBlock extends HtmlBlock {
         long totalSkipped = 0;
         while (totalSkipped < start) {
           long ret = logReader.skip(start - totalSkipped);
-          if (ret < 0) {
-            throw new IOException( "Premature EOF from container log");
+          if (ret == 0) {
+            //Read one byte
+            int nextByte = logReader.read();
+            // Check if we have reached EOF
+            if (nextByte == -1) {
+              throw new IOException( "Premature EOF from container log");
+            }
+            ret = 1;
           }
           totalSkipped += ret;
         }