From e742ae2157d2b41861975fa35d8de5483210a801 Mon Sep 17 00:00:00 2001
From: Yumin Qi <yumin.qi@oracle.com>
Date: Fri, 22 Jun 2012 15:39:16 -0700
Subject: [PATCH] 7177128: SA cannot get correct system properties after
 7126277

Bug fix of 7126277 changed hashing algorithm and also changed key as final field, this led SA unable to set correct value for key. Solution by reading key/value and insert them into the new table.

Reviewed-by: dholmes, mikael
---
 .../jvm/hotspot/utilities/ObjectReader.java   | 128 ++++++++++++++++--
 1 file changed, 118 insertions(+), 10 deletions(-)

diff --git a/hotspot/agent/src/share/classes/sun/jvm/hotspot/utilities/ObjectReader.java b/hotspot/agent/src/share/classes/sun/jvm/hotspot/utilities/ObjectReader.java
index 55cb2995621..1f17a7fdb63 100644
--- a/hotspot/agent/src/share/classes/sun/jvm/hotspot/utilities/ObjectReader.java
+++ b/hotspot/agent/src/share/classes/sun/jvm/hotspot/utilities/ObjectReader.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2007, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -85,6 +85,21 @@ public class ObjectReader {
       this(new ProcImageClassLoader());
    }
 
+   static void debugPrintln(String msg) {
+      if (DEBUG) {
+         System.err.println("DEBUG>" + msg);
+      }
+   }
+
+   static void debugPrintStackTrace(Exception exp) {
+      if (DEBUG) {
+         StackTraceElement[] els = exp.getStackTrace();
+         for (int i = 0; i < els.length; i++) {
+            System.err.println("DEBUG>" + els[i].toString());
+         }
+      }
+   }
+
    public Object readObject(Oop oop) throws ClassNotFoundException {
       if (oop instanceof Instance) {
          return readInstance((Instance) oop);
@@ -120,13 +135,96 @@ public class ObjectReader {
    }
 
    protected Symbol javaLangString;
+   protected Symbol javaUtilHashtableEntry;
+   protected Symbol javaUtilHashtable;
+   protected Symbol javaUtilProperties;
+
+   protected Symbol getVMSymbol(String name) {
+      return VM.getVM().getSymbolTable().probe(name);
+   }
+
    protected Symbol javaLangString() {
       if (javaLangString == null) {
-         javaLangString = VM.getVM().getSymbolTable().probe("java/lang/String");
+         javaLangString = getVMSymbol("java/lang/String");
       }
       return javaLangString;
    }
 
+   protected Symbol javaUtilHashtableEntry() {
+      if (javaUtilHashtableEntry == null) {
+         javaUtilHashtableEntry = getVMSymbol("java/util/Hashtable$Entry");
+      }
+      return javaUtilHashtableEntry;
+   }
+
+   protected Symbol javaUtilHashtable() {
+      if (javaUtilHashtable == null) {
+         javaUtilHashtable = getVMSymbol("java/util/Hashtable");
+      }
+      return javaUtilHashtable;
+   }
+
+   protected Symbol javaUtilProperties() {
+      if (javaUtilProperties == null) {
+         javaUtilProperties = getVMSymbol("java/util/Properties");
+      }
+      return javaUtilProperties;
+   }
+
+   private void setHashtableEntry(java.util.Hashtable p, Oop oop) {
+      InstanceKlass ik = (InstanceKlass)oop.getKlass();
+      OopField keyField = (OopField)ik.findField("key", "Ljava/lang/Object;");
+      OopField valueField = (OopField)ik.findField("value", "Ljava/lang/Object;");
+      OopField nextField = (OopField)ik.findField("next", "Ljava/util/Hashtable$Entry;");
+      if (DEBUG) {
+         if (Assert.ASSERTS_ENABLED) {
+            Assert.that(ik.getName().equals(javaUtilHashtableEntry()), "Not a Hashtable$Entry?");
+            Assert.that(keyField != null && valueField != null && nextField != null, "Invalid fields!");
+         }
+      }
+
+      Object key = null;
+      Object value = null;
+      Oop next = null;
+      try {
+         key = readObject(keyField.getValue(oop));
+         value = readObject(valueField.getValue(oop));
+         next =  (Oop)nextField.getValue(oop);
+         // For Properties, should use setProperty(k, v). Since it only runs in SA
+         // using put(k, v) should be OK.
+         p.put(key, value);
+         if (next != null) {
+            setHashtableEntry(p, next);
+         }
+      } catch (ClassNotFoundException ce) {
+         if( DEBUG) {
+            debugPrintln("Class not found " + ce);
+            debugPrintStackTrace(ce);
+         }
+      }
+   }
+
+   protected Object getHashtable(Instance oop, boolean isProperties) {
+      InstanceKlass k = (InstanceKlass)oop.getKlass();
+      OopField tableField = (OopField)k.findField("table", "[Ljava/util/Hashtable$Entry;");
+      if (tableField == null) {
+         debugPrintln("Could not find field of [Ljava/util/Hashtable$Entry;");
+         return null;
+      }
+      java.util.Hashtable table = (isProperties) ? new java.util.Properties()
+                                                 : new java.util.Hashtable();
+      ObjArray kvs = (ObjArray)tableField.getValue(oop);
+      long size = kvs.getLength();
+      debugPrintln("Hashtable$Entry Size = " + size);
+      for (long i=0; i<size; i++) {
+         Oop entry = kvs.getObjAt(i);
+         if (entry != null && entry.isInstance()) {
+            setHashtableEntry(table, entry);
+         }
+      }
+      return table;
+   }
+
    public Object readInstance(Instance oop) throws ClassNotFoundException {
       Object result = getFromObjTable(oop);
       if (result == null) {
@@ -134,11 +232,21 @@ public class ObjectReader {
          // Handle java.lang.String instances differently. As part of JSR-133, fields of immutable
          // classes have been made final. The algorithm below will not be able to read Strings from
          // debuggee (can't use reflection to set final fields). But, need to read Strings is very
-         // important. FIXME: need a framework to handle many other special cases.
+         // important.
+         // Same for Hashtable, key and hash are final, could not be set in the algorithm too.
+         // FIXME: need a framework to handle many other special cases.
          if (kls.getName().equals(javaLangString())) {
             return OopUtilities.stringOopToString(oop);
          }
 
+         if (kls.getName().equals(javaUtilHashtable())) {
+            return getHashtable(oop, false);
+         }
+
+         if (kls.getName().equals(javaUtilProperties())) {
+            return getHashtable(oop, true);
+         }
+
          Class clz = readClass(kls);
          try {
             result = clz.newInstance();
@@ -164,8 +272,8 @@ public class ObjectReader {
                   break;
                } catch (Exception exp) {
                   if (DEBUG) {
-                     System.err.println("Can't create object using " + c);
-                     exp.printStackTrace();
+                     debugPrintln("Can't create object using " + c);
+                     debugPrintStackTrace(exp);
                   }
                }
             }
@@ -329,8 +437,8 @@ public class ObjectReader {
                                      arrayObj[ifd.getIndex()] = readObject(field.getValue(getObj()));
                                   } catch (Exception e) {
                                      if (DEBUG) {
-                                        System.err.println("Array element set failed for " + ifd);
-                                        e.printStackTrace();
+                                        debugPrintln("Array element set failed for " + ifd);
+                                        debugPrintStackTrace(e);
                                      }
                                   }
                                }
@@ -348,8 +456,8 @@ public class ObjectReader {
 
       private void printFieldSetError(java.lang.reflect.Field f, Exception ex) {
          if (DEBUG) {
-            if (f != null) System.err.println("Field set failed for " + f);
-            ex.printStackTrace();
+            if (f != null) debugPrintln("Field set failed for " + f);
+            debugPrintStackTrace(ex);
          }
       }
 
@@ -601,7 +709,7 @@ public class ObjectReader {
             return Class.forName(className, true, cl);
          } catch (Exception e) {
             if (DEBUG) {
-               System.err.println("Can't load class " + className);
+               debugPrintln("Can't load class " + className);
             }
             throw new RuntimeException(e);
          }