Fixing DNS memory leaks.

Some of the changes only clean up at termination to make perftools
happt, but there were some "real" leaks as well.

This fixes all DNS leaks I could reproducem, including most likely
what's reported in #534. Closing #534.

I'm also adding a new btest subdir core/leaks with tests requiring
perftools support. These don't compare against base lines but abort
whenever perftools reports a leak (with stack information to track it
down). Right now, these are passing.

src/DNS_Mgr.cc

@@ -592,6 +592,8 @@ void DNS_Mgr::Resolve()
 				}
 			else
 				--num_pending;
+
+			delete dr;
 			}
 		}
 
@@ -847,6 +849,7 @@ const char* DNS_Mgr::LookupAddrInCache(dns_mgr_addr_type addr)
 	if ( d->Expired() )
 		{
 		dns_mgr->addr_mappings.Remove(&h);
+		delete d;
 		return 0;
 		}
 
@@ -866,6 +869,7 @@ TableVal* DNS_Mgr::LookupNameInCache(string name)
 		{
 		HashKey h(name.c_str());
 		dns_mgr->host_mappings.Remove(&h);
+		delete d;
 		return 0;
 		}
 
@@ -1038,14 +1042,29 @@ void DNS_Mgr::CheckAsyncHostRequest(const char* host, bool timeout)
 		}
 	}
 
+void DNS_Mgr::Flush()
+	{
+	DoProcess(false);
+
+	IterCookie* cookie = addr_mappings.InitForIteration();
+	DNS_Mapping* dm;
+
+	host_mappings.Clear();
+	addr_mappings.Clear();
+	}
+
 void DNS_Mgr::Process()
 	{
+	DoProcess(false);
+	}
 
+void DNS_Mgr::DoProcess(bool flush)
+	{
 	while ( asyncs_timeouts.size() > 0 )
 		{
 		AsyncRequest* req = asyncs_timeouts.top();
 
-		if ( req->time + DNS_TIMEOUT > current_time() )
+		if ( req->time + DNS_TIMEOUT > current_time() || flush )
 			break;
 
 		if ( req->IsAddrReq() )
@@ -1086,6 +1105,8 @@ void  DNS_Mgr::Process()
 			CheckAsyncHostRequest(dr->ReqHost(), true);
 
 		IssueAsyncRequests();
+
+		delete dr;
 		}
 	}
 

src/DNS_Mgr.h

@@ -49,6 +49,7 @@ public:
 	virtual ~DNS_Mgr();
 
 	bool Init();
+	void Flush();
 
 	// Looks up the address or addresses of the given host, and returns
 	// a set of addr.
@@ -111,6 +112,9 @@ protected:
 	void CheckAsyncAddrRequest(dns_mgr_addr_type addr, bool timeout);
 	void CheckAsyncHostRequest(const char* host, bool timeout);
 
+	// Process outstanding requests.
+	void DoProcess(bool flush);
+
 	// IOSource interface.
 	virtual void GetFds(int* read, int* write, int* except);
 	virtual double NextTimestamp(double* network_time);

src/Dict.cc

@@ -67,6 +67,19 @@ Dictionary::Dictionary(dict_order ordering, int initial_size)
 	}
 
 Dictionary::~Dictionary()
+	{
+	DeInit();
+	delete order;
+	}
+
+void Dictionary::Clear()
+	{
+	DeInit();
+	Init(2);
+	tbl2 = 0;
+	}
+
+void Dictionary::DeInit()
 	{
 	for ( int i = 0; i < num_buckets; ++i )
 		if ( tbl[i] )
@@ -84,7 +97,6 @@ Dictionary::~Dictionary()
 			}
 
 	delete [] tbl;
-	delete order;
 
 	if ( tbl2 == 0 )
 		return;
@@ -103,7 +115,9 @@ Dictionary::~Dictionary()
 
 			delete chain;
 			}
+
 	delete [] tbl2;
+	tbl2 = 0;
 	}
 
 void* Dictionary::Lookup(const void* key, int key_size, hash_t hash) const

src/Dict.h

@@ -118,11 +118,15 @@ public:
 	void MakeRobustCookie(IterCookie* cookie)
 		{ cookies.append(cookie); }
 
+	// Remove all entries.
+	void Clear();
+
 	unsigned int MemoryAllocation() const;
 
 private:
 	void Init(int size);
 	void Init2(int size);	// initialize second table for resizing
+	void DeInit();
 
 	// Internal version of Insert().
 	void* Insert(DictEntry* entry, int copy_key);

src/Val.cc

@@ -1463,6 +1463,7 @@ TableVal* ListVal::ConvertToSet() const
 	loop_over_list(vals, i)
 		t->Assign(vals[i], 0);
 
+	Unref(s);
 	return t;
 	}
 
@@ -1582,6 +1583,7 @@ TableVal::TableVal(TableType* t, Attributes* a) : MutableVal(t)
 
 void TableVal::Init(TableType* t)
 	{
+	::Ref(t);
 	table_type = t;
 	expire_expr = 0;
 	expire_time = 0;
@@ -1604,6 +1606,7 @@ TableVal::~TableVal()
 	if ( timer )
 		timer_mgr->Cancel(timer);
 
+	Unref(table_type);
 	delete table_hash;
 	delete AsTable();
 	delete subnets;

src/Val.h

@@ -869,7 +869,7 @@ protected:
 
 	DECLARE_SERIAL(TableVal);
 
-	const TableType* table_type;
+	TableType* table_type;
 	CompositeHash* table_hash;
 	Attributes* attrs;
 	double expire_time;

src/bro.bif

@@ -2828,13 +2828,15 @@ public:
 	// Overridden from DNS_Mgr:Lookup:Callback.
 	virtual void Resolved(const char* name)
 		{
-		trigger->Cache(call, new StringVal(name));
+		Val* result = new StringVal(name);
+		trigger->Cache(call, result);
+		Unref(result);
 		trigger->Release();
 		}
 
 	virtual void Resolved(TableVal* addrs)
 		{
-		Ref(addrs);
+		// No Ref() for addrs.
 		trigger->Cache(call, addrs);
 		trigger->Release();
 		}
@@ -2842,12 +2844,19 @@ public:
 	virtual void Timeout()
 		{
 		if ( lookup_name )
-			trigger->Cache(call, new StringVal("<\?\?\?>"));
+			{
+			Val* result = new StringVal("<\?\?\?>");
+			trigger->Cache(call, result);
+			Unref(result);
+			}
+
 		else
 			{
 			ListVal* lv = new ListVal(TYPE_ADDR);
 			lv->Append(new AddrVal("0.0.0.0"));
-			trigger->Cache(call, lv->ConvertToSet());
+			Val* result = lv->ConvertToSet();
+			trigger->Cache(call, result);
+			Unref(result);
 			Unref(lv);
 			}
 

src/main.cc

@@ -229,6 +229,8 @@ void done_with_network()
 
 	dpm->Done();
 	timer_mgr->Expire();
+	dns_mgr->Flush();
+	mgr.Drain();
 	mgr.Drain();
 
 	if ( remote_serializer )

testing/btest/core/leaks/dns.bro

@@ -0,0 +1,48 @@
+# Needs perftools support.
+#
+# @TEST-REQUIRES: bro  --help 2>&1 | grep -q mem-leaks
+#
+# @TEST-EXEC: HEAP_CHECK_DUMP_DIRECTORY=. HEAPCHECK=local bro -m -r $TRACES/wikipedia.trace %INPUT
+
+# Add the state tracking information variable to the connection record
+
+event connection_established(c: connection)
+	{
+	when ( local addrs = lookup_hostname("localhost") )
+		{
+		print "1a", c$id$resp_h, addrs;
+		}
+	timeout 100secs
+		{
+		print "1b", c$id$resp_h;
+		}
+
+	when ( local addrs2 = lookup_hostname("qq.ww.ee.rrrrr") )
+		{
+		print "2a", c$id$resp_h, addrs2;
+		}
+	timeout 100secs
+		{
+		print "2b", c$id$resp_h;
+		}
+
+	when ( local a = lookup_addr(c$id$resp_h) )
+		{
+		print "3a", c$id$resp_h, a;
+		}
+	timeout 100secs
+		{
+		print "3b", c$id$resp_h;
+		}
+
+	when ( local a2 = lookup_addr(1.2.3.4) )
+		{
+		print "4a", c$id$resp_h, a2;
+		}
+	timeout 100secs
+		{
+		print "4b", c$id$resp_h;
+		}
+		
+	}
+