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Posted to dev@tomcat.apache.org by ma...@apache.org on 2009/12/21 17:38:30 UTC

svn commit: r892872 - in /tomcat/tc6.0.x/trunk: ./ STATUS.txt java/org/apache/catalina/session/PersistentManagerBase.java webapps/docs/changelog.xml

Author: markt
Date: Mon Dec 21 16:38:29 2009
New Revision: 892872

URL: http://svn.apache.org/viewvc?rev=892872&view=rev
Log:
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=47930
Prevent parallel requests for the same session causing the PersistentManager to create multiple session objects for a single session
  

Modified:
    tomcat/tc6.0.x/trunk/   (props changed)
    tomcat/tc6.0.x/trunk/STATUS.txt
    tomcat/tc6.0.x/trunk/java/org/apache/catalina/session/PersistentManagerBase.java
    tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml

Propchange: tomcat/tc6.0.x/trunk/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon Dec 21 16:38:29 2009
@@ -1,2 +1,2 @@
 /tomcat:883362
-/tomcat/trunk:601180,606992,612607,630314,640888,652744,653247,666232,673796,673820,677910,683969,683982,684001,684081,684234,684269-684270,685177,687503,687645,689402,690781,691392,691805,692748,693378,694992,695053,695311,696780,696782,698012,698227,698236,698613,699427,699634,701355,709294,709811,709816,710063,710066,710125,710205,711126,711600,712461,712467,713953,714002,718360,719119,719124,719602,719626,719628,720046,720069,721040,721286,721708,721886,723404,723738,726052,727303,728032,728768,728947,729057,729567,729569,729571,729681,729809,729815,729934,730250,730590,731651,732859,732863,734734,740675,740684,742677,742697,742714,744160,744238,746321,746384,746425,747834,747863,748344,750258,750291,750921,751286-751287,751289,751295,753039,757335,757774,758249,758365,758596,758616,758664,759074,761601,762868,762929,762936-762937,763166,763183,763193,763228,763262,763298,763302,763325,763599,763611,763654,763681,763706,764985,764997,765662,768335,769979,770716,770809,77
 0876,772872,776921,776924,776935,776945,777464,777466,777576,777625,778379,778523-778524,781528,781779,782145,782791,783316,783696,783724,783756,783762,783766,783863,783934,784453,784602,784614,785381,785688,785768,785859,786468,786487,786490,786496,786667,787627,787770,787985,789389,790405,791041,791184,791194,791224,791243,791326,791328,791789,792740,793372,793757,793882,793981,794082,794673,794822,795043,795152,795210,795457,795466,797168,797425,797596,797607,802727,802940,804462,804544,804734,805153,809131,809603,810916,810977,812125,812137,812432,813001,813013,813866,814180,814708,814876,815972,816252,817442,817822,819339,819361,820110,820132,820874,820954,821397,828196,828201,828210,828225,828759,830378-830379,830999,831106,831774,831785,831828,831850,831860,832214,832218,833121,833545,834047,835036,835336,836405,881396,881412,883130,883134,883146,883165,883177,883362,883565,884341,885038,885991,886019,888072,889363,889606,889716,890139,890265,890349-890350,890417,8911
 85-891187,891583,892198,892415,892464,892555
+/tomcat/trunk:601180,606992,612607,630314,640888,652744,653247,666232,673796,673820,677910,683969,683982,684001,684081,684234,684269-684270,685177,687503,687645,689402,690781,691392,691805,692748,693378,694992,695053,695311,696780,696782,698012,698227,698236,698613,699427,699634,701355,709294,709811,709816,710063,710066,710125,710205,711126,711600,712461,712467,713953,714002,718360,719119,719124,719602,719626,719628,720046,720069,721040,721286,721708,721886,723404,723738,726052,727303,728032,728768,728947,729057,729567,729569,729571,729681,729809,729815,729934,730250,730590,731651,732859,732863,734734,740675,740684,742677,742697,742714,744160,744238,746321,746384,746425,747834,747863,748344,750258,750291,750921,751286-751287,751289,751295,753039,757335,757774,758249,758365,758596,758616,758664,759074,761601,762868,762929,762936-762937,763166,763183,763193,763228,763262,763298,763302,763325,763599,763611,763654,763681,763706,764985,764997,765662,768335,769979,770716,770809,77
 0876,772872,776921,776924,776935,776945,777464,777466,777576,777625,778379,778523-778524,781528,781779,782145,782791,783316,783696,783724,783756,783762,783766,783863,783934,784453,784602,784614,785381,785688,785768,785859,786468,786487,786490,786496,786667,787627,787770,787985,789389,790405,791041,791184,791194,791224,791243,791326,791328,791789,792740,793372,793757,793882,793981,794082,794673,794822,795043,795152,795210,795457,795466,797168,797425,797596,797607,802727,802940,804462,804544,804734,805153,809131,809603,810916,810977,812125,812137,812432,813001,813013,813866,814180,814708,814876,815972,816252,817442,817822,819339,819361,820110,820132,820874,820954,821397,828196,828201,828210,828225,828759,830378-830379,830999,831106,831774,831785,831828,831850,831860,832214,832218,833121,833545,834047,835036,835336,836405,881396,881412,883130,883134,883146,883165,883177,883362,883565,884341,885038,885991,886019,888072,889363,889606,889716,890139,890265,890349-890350,890417,8911
 85-891187,891583,892198,892341,892415,892464,892555,892814,892817

Modified: tomcat/tc6.0.x/trunk/STATUS.txt
URL: http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/STATUS.txt?rev=892872&r1=892871&r2=892872&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/STATUS.txt (original)
+++ tomcat/tc6.0.x/trunk/STATUS.txt Mon Dec 21 16:38:29 2009
@@ -302,20 +302,6 @@
 
          I won't oppose the patch. I have to think a bit more about it.
 
-* Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=47930
-  Prevent parallel requests for the same session causing the PersistentManager
-  to create multiple session objects for a single session
-  http://svn.apache.org/viewvc?rev=892341&view=rev
-  +1: markt, rjung, jim
-  +1: kkolinko: I am OK to commit r892341 as is, though r892817 proposed
-    below adds slight improvements
-  -1: 
-  Additional patches:
-  http://svn.apache.org/viewvc?rev=892814&view=rev (tabs replaced by spaces, no functional change)
-  http://svn.apache.org/viewvc?rev=892817&view=rev (sebb's/kkolinko's comments)
-  +1: kkolinko, markt, rjung, jim
-  -1:
-
 * Remove unneeded line from the method that normalizes decodedURI.
   http://svn.apache.org/viewvc?rev=892812&view=rev
   +1: kkolinko, markt, rjung, jim

Modified: tomcat/tc6.0.x/trunk/java/org/apache/catalina/session/PersistentManagerBase.java
URL: http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/java/org/apache/catalina/session/PersistentManagerBase.java?rev=892872&r1=892871&r2=892872&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/java/org/apache/catalina/session/PersistentManagerBase.java (original)
+++ tomcat/tc6.0.x/trunk/java/org/apache/catalina/session/PersistentManagerBase.java Mon Dec 21 16:38:29 2009
@@ -24,6 +24,9 @@
 import java.security.AccessController;
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
+import java.util.HashMap;
+import java.util.Map;
+
 import org.apache.catalina.Container;
 import org.apache.catalina.Context;
 import org.apache.catalina.Lifecycle;
@@ -205,6 +208,13 @@
     protected long processingTime = 0;
 
 
+    /**
+     * Sessions currently being swapped in and the associated locks
+     */
+    private final Map<String,Object> sessionSwapInLocks =
+    	new HashMap<String,Object>();
+
+
     // ------------------------------------------------------------- Properties
 
     
@@ -771,53 +781,88 @@
         if (store == null)
             return null;
 
+        Object swapInLock = null;
+
+        /*
+         * The purpose of this sync and these locks is to make sure that a
+         * session is only loaded once. It doesn't matter if the lock is removed
+         * and then another thread enters this method and tries to load the same
+         * session. That thread will re-create a swapIn lock for that session,
+         * quickly find that the session is already in sessions, use it and
+         * carry on.
+         */
+        synchronized (this) {
+            swapInLock = sessionSwapInLocks.get(id);
+            if (swapInLock == null) {
+                swapInLock = new Object();
+                sessionSwapInLocks.put(id, swapInLock);
+            }
+        }
+
         Session session = null;
-        try {
-            if (SecurityUtil.isPackageProtectionEnabled()){
-                try{
-                    session = (Session) 
-                      AccessController.doPrivileged(new PrivilegedStoreLoad(id));
-                }catch(PrivilegedActionException ex){
-                    Exception exception = ex.getException();
-                    log.error("Exception in the Store during swapIn: "
-                              + exception);
-                    if (exception instanceof IOException){
-                        throw (IOException)exception;
-                    } else if (exception instanceof ClassNotFoundException) {
-                        throw (ClassNotFoundException)exception;
+
+        synchronized (swapInLock) {
+            // First check to see if another thread has loaded the session into
+            // the manager
+            session = sessions.get(id);
+
+            if (session == null) {
+                try {
+                    if (SecurityUtil.isPackageProtectionEnabled()){
+                        try {
+                            session = (Session) AccessController.doPrivileged(
+                                    new PrivilegedStoreLoad(id));
+                        } catch (PrivilegedActionException ex) {
+                            Exception e = ex.getException();
+                            log.error(sm.getString(
+                                    "persistentManager.swapInException", id),
+                                    e);
+                            if (e instanceof IOException){
+                                throw (IOException)e;
+                            } else if (e instanceof ClassNotFoundException) {
+                                throw (ClassNotFoundException)e;
+                            }
+                        }
+                    } else {
+                         session = store.load(id);
                     }
+                } catch (ClassNotFoundException e) {
+                    String msg = sm.getString(
+                            "persistentManager.deserializeError", id);
+                    log.error(msg, e);
+                    throw new IllegalStateException(msg, e);
                 }
-            } else {
-                 session = store.load(id);
-            }   
-        } catch (ClassNotFoundException e) {
-            log.error(sm.getString("persistentManager.deserializeError", id, e));
-            throw new IllegalStateException
-                (sm.getString("persistentManager.deserializeError", id, e));
-        }
 
-        if (session == null)
-            return (null);
-
-        if (!session.isValid()) {
-            log.error("session swapped in is invalid or expired");
-            session.expire();
-            removeSession(id);
-            return (null);
-        }
+                if (session != null && !session.isValid()) {
+                    log.error(sm.getString(
+                            "persistentManager.swapInInvalid", id));
+                    session.expire();
+                    removeSession(id);
+                    session = null;
+                }
 
-        if(log.isDebugEnabled())
-            log.debug(sm.getString("persistentManager.swapIn", id));
+                if (session != null) {
+                    if(log.isDebugEnabled())
+                        log.debug(sm.getString("persistentManager.swapIn", id));
 
-        session.setManager(this);
-        // make sure the listeners know about it.
-        ((StandardSession)session).tellNew();
-        add(session);
-        ((StandardSession)session).activate();
-        // endAccess() to ensure timeouts happen correctly.
-        // access() to keep access count correct or it will end up negative
-        session.access();
-        session.endAccess();
+                    session.setManager(this);
+                    // make sure the listeners know about it.
+                    ((StandardSession)session).tellNew();
+                    add(session);
+                    ((StandardSession)session).activate();
+                    // endAccess() to ensure timeouts happen correctly.
+                    // access() to keep access count correct or it will end up
+                    // negative
+                    session.access();
+                    session.endAccess();
+                }
+            }
+        }
+
+        // Make sure the lock is removed
+        synchronized (this) {
+            sessionSwapInLocks.remove(id);
+        }
 
         return (session);
 

Modified: tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml
URL: http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml?rev=892872&r1=892871&r2=892872&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml Mon Dec 21 16:38:29 2009
@@ -205,6 +205,10 @@
         provided by Uwe Günther. (markt)
       </fix>
       <fix>
+        <bug>47930</bug>: Fix thread safety issues on session swap-in in the
+        persistent session manager. (markt/kkolinko)
+      </fix>
+      <fix>
         <bug>47976</bug>: Correct usage message and Javadoc for
         <code>org.apache.catalina.startup.Catalina</code>. (markt)
       </fix>



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