Add fix for patch #166 (this is a reasonably big one)

git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@5679 e03df62e-2008-0410-955e-edbf42e46eb7

7 files changed, 66 insertions, 17 deletions

diff --git a/include/dns.h b/include/dns.h
index 79b286233..4a1335cc7 100644
--- a/include/dns.h
+++ b/include/dns.h
@@ -48,6 +48,7 @@ using irc::sockets::insp_sockaddr;
 using irc::sockets::insp_inaddr;
 
 class InspIRCd;
+class Module;
 
 /**
  * Result status, used internally
@@ -69,7 +70,8 @@ enum ResolverError
 	RESOLVER_NXDOMAIN	=	2,
 	RESOLVER_NOTREADY	=	3,
 	RESOLVER_BADIP		=	4,
-	RESOLVER_TIMEOUT	=	5
+	RESOLVER_TIMEOUT	=	5,
+	RESLOVER_FORCEUNLOAD	=	6
 };
 
 /**
@@ -147,6 +149,10 @@ class Resolver : public Extensible
 	 */
 	InspIRCd* ServerInstance;
 	/**
+	 * Pointer to creator module (if any, or NULL)
+	 */
+	Module* Creator;
+	/**
 	 * The input data, either a host or an IP address
 	 */
 	std::string input;
@@ -193,8 +199,14 @@ class Resolver : public Extensible
 	 * event a lookup could not be allocated, or a similar hard error occurs such as
 	 * the network being down. This will also be thrown if an invalid IP address is
 	 * passed when resolving a 'PTR' record.
+	 *
+	 * NOTE: If you are instantiating your DNS lookup from a module, you should set the
+	 * value of creator to point at your Module class. This way if your module is unloaded
+	 * whilst lookups are in progress, they can be safely removed and your module will not
+	 * crash the server.
 	 */
-	Resolver(InspIRCd* Instance, const std::string &source, QueryType qt);
+	Resolver(InspIRCd* Instance, const std::string &source, QueryType qt, Module* creator = NULL);
+
 	/**
 	 * The default destructor does nothing.
 	 */
@@ -220,6 +232,11 @@ class Resolver : public Extensible
 	 * this method will return -1.
 	 */
 	int GetId();
+
+	/**
+	 * Returns the creator module, or NULL
+	 */
+	Module* GetCreator();
 };
 
 /** DNS is a singleton class used by the core to dispatch dns
@@ -364,6 +381,13 @@ class DNS : public EventHandler
 	 * Turn an in6_addr into a .ip6.arpa domain
 	 */
 	static void MakeIP6Int(char* query, const in6_addr *ip);
+
+	/**
+	 * Clean out all dns resolvers owned by a particular
+	 * module, to make unloading a module safe if there
+	 * are dns requests currently in progress.
+	 */
+	void CleanResolvers(Module* module);
 };
 
 #endif
diff --git a/src/dns.cpp b/src/dns.cpp
index 3381c18fa..23e1dfcab 100644
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -870,7 +870,7 @@ DNS::~DNS()
 }
 
 /** High level abstraction of dns used by application at large */
-Resolver::Resolver(InspIRCd* Instance, const std::string &source, QueryType qt) : ServerInstance(Instance), input(source), querytype(qt)
+Resolver::Resolver(InspIRCd* Instance, const std::string &source, QueryType qt, Module* creator) : ServerInstance(Instance), Creator(creator), input(source), querytype(qt)
 {
 	ServerInstance->Log(DEBUG,"Instance: %08x %08x",Instance, ServerInstance);
 
@@ -948,6 +948,11 @@ int Resolver::GetId()
 	return this->myid;
 }
 
+Module* Resolver::GetCreator()
+{
+	return this->Creator;
+}
+
 /** Process a socket read event */
 void DNS::HandleEvent(EventType et, int errornum)
 {
@@ -1025,6 +1030,22 @@ bool DNS::AddResolverClass(Resolver* r)
 	}
 }
 
+void DNS::CleanResolvers(Module* module)
+{
+	for (int i = 0; i < MAX_REQUEST_ID; i++)
+	{
+		if (Classes[i])
+		{
+			if (Classes[i]->GetCreator() == module)
+			{
+				Classes[i]->OnError(RESLOVER_FORCEUNLOAD, "Parent module is unloading");
+				delete Classes[i];
+				Classes[i] = NULL;
+			}
+		}
+	}
+}
+
 /** Generate pseudo-random number */
 unsigned long DNS::PRNG()
 {
diff --git a/src/inspircd.cpp b/src/inspircd.cpp
index 1b636bc87..9521f1b22 100644
--- a/src/inspircd.cpp
+++ b/src/inspircd.cpp
@@ -508,6 +508,9 @@ bool InspIRCd::UnloadModule(const char* filename)
 				modules[j]->OnCleanup(TYPE_USER,u->second);
 			}
 
+			/* Tidy up any dangling resolvers */
+			this->Res->CleanResolvers(modules[j]);
+
 			FOREACH_MOD_I(this,I_OnUnloadModule,OnUnloadModule(modules[j],Config->module_names[j]));
 
 			for(int t = 0; t < 255; t++)
diff --git a/src/modules/extra/m_pgsql.cpp b/src/modules/extra/m_pgsql.cpp
index 1bd19e964..f4392a4ed 100644
--- a/src/modules/extra/m_pgsql.cpp
+++ b/src/modules/extra/m_pgsql.cpp
@@ -96,7 +96,7 @@ class SQLresolver : public Resolver
 	ModulePgSQL* mod;
  public:
 	SQLresolver(ModulePgSQL* m, InspIRCd* Instance, const SQLhost& hi)
-	: Resolver(Instance, hi.host, DNS_QUERY_FORWARD), host(hi), mod(m)
+	: Resolver(Instance, hi.host, DNS_QUERY_FORWARD, (Module*)m), host(hi), mod(m)
 	{
 	}
 
diff --git a/src/modules/m_cgiirc.cpp b/src/modules/m_cgiirc.cpp
index a8d071e31..ec2ac6129 100644
--- a/src/modules/m_cgiirc.cpp
+++ b/src/modules/m_cgiirc.cpp
@@ -55,8 +55,8 @@ class CGIResolver : public Resolver
 	userrec* them;
 	bool notify;
  public:
-	CGIResolver(InspIRCd* ServerInstance, bool NotifyOpers, const std::string &source, bool forward, userrec* u, int userfd, const std::string &type)
-		: Resolver(ServerInstance, source, forward ? DNS_QUERY_FORWARD : DNS_QUERY_REVERSE), typ(type), theirfd(userfd), them(u), notify(NotifyOpers) { }
+	CGIResolver(Module* me, InspIRCd* ServerInstance, bool NotifyOpers, const std::string &source, bool forward, userrec* u, int userfd, const std::string &type)
+		: Resolver(ServerInstance, source, forward ? DNS_QUERY_FORWARD : DNS_QUERY_REVERSE, me), typ(type), theirfd(userfd), them(u), notify(NotifyOpers) { }
 
 	virtual void OnLookupComplete(const std::string &result)
 	{
@@ -263,7 +263,7 @@ public:
 
 				try
 				{
-					CGIResolver* r = new CGIResolver(ServerInstance, NotifyOpers, user->password, false, user, user->GetFd(), "PASS");
+					CGIResolver* r = new CGIResolver(this, ServerInstance, NotifyOpers, user->password, false, user, user->GetFd(), "PASS");
 					ServerInstance->AddResolver(r);
 				}
 				catch (ModuleException& e)
@@ -319,7 +319,7 @@ public:
 		try
 		{
 			ServerInstance->Log(DEBUG,"MAKE RESOLVER: %s %d %s",newip, user->GetFd(), "IDENT");
-			CGIResolver* r = new CGIResolver(ServerInstance, NotifyOpers, newip, false, user, user->GetFd(), "IDENT");
+			CGIResolver* r = new CGIResolver(this, ServerInstance, NotifyOpers, newip, false, user, user->GetFd(), "IDENT");
 			ServerInstance->AddResolver(r);
 		}
 		catch (ModuleException& e)
diff --git a/src/modules/m_spanningtree.cpp b/src/modules/m_spanningtree.cpp
index d9bb93e3e..92c95c525 100644
--- a/src/modules/m_spanningtree.cpp
+++ b/src/modules/m_spanningtree.cpp
@@ -3585,7 +3585,7 @@ class ServernameResolver : public Resolver
 	Link MyLink;
 	SpanningTreeUtilities* Utils;
  public: 
-	ServernameResolver(SpanningTreeUtilities* Util, InspIRCd* Instance, const std::string &hostname, Link x) : Resolver(Instance, hostname, DNS_QUERY_FORWARD), MyLink(x), Utils(Util)
+	ServernameResolver(Module* me, SpanningTreeUtilities* Util, InspIRCd* Instance, const std::string &hostname, Link x) : Resolver(Instance, hostname, DNS_QUERY_FORWARD, me), MyLink(x), Utils(Util)
 	{
 		/* Nothing in here, folks */
 	}
@@ -3630,7 +3630,7 @@ class SecurityIPResolver : public Resolver
 	Link MyLink;
 	SpanningTreeUtilities* Utils;
  public:
-	SecurityIPResolver(SpanningTreeUtilities* U, InspIRCd* Instance, const std::string &hostname, Link x) : Resolver(Instance, hostname, DNS_QUERY_FORWARD), MyLink(x), Utils(U)
+	SecurityIPResolver(Module* me, SpanningTreeUtilities* U, InspIRCd* Instance, const std::string &hostname, Link x) : Resolver(Instance, hostname, DNS_QUERY_FORWARD, me), MyLink(x), Utils(U)
 	{
 	}
 
@@ -3932,7 +3932,7 @@ void SpanningTreeUtilities::ReadConfiguration(bool rebind)
 				{
 					try
 					{
-						SecurityIPResolver* sr = new SecurityIPResolver(this, ServerInstance, L.IPAddr, L);
+						SecurityIPResolver* sr = new SecurityIPResolver((Module*)this->Creator, this, ServerInstance, L.IPAddr, L);
 						ServerInstance->AddResolver(sr);
 					}
 					catch (ModuleException& e)
@@ -4408,7 +4408,7 @@ class ModuleSpanningTree : public Module
 		{
 			try
 			{
-				ServernameResolver* snr = new ServernameResolver(Utils, ServerInstance,x->IPAddr, *x);
+				ServernameResolver* snr = new ServernameResolver((Module*)this, Utils, ServerInstance,x->IPAddr, *x);
 				ServerInstance->AddResolver(snr);
 			}
 			catch (ModuleException& e)
diff --git a/src/modules/m_testcommand.cpp b/src/modules/m_testcommand.cpp
index 9da6788cd..50853d4b3 100644
--- a/src/modules/m_testcommand.cpp
+++ b/src/modules/m_testcommand.cpp
@@ -31,7 +31,7 @@ class MyV6Resolver : public Resolver
 {
 	bool fw;
  public:
-	MyV6Resolver(const std::string &source, bool forward) : Resolver(ServerInstance, source, forward ? DNS_QUERY_AAAA : DNS_QUERY_PTR6)
+	MyV6Resolver(Module* me, const std::string &source, bool forward) : Resolver(ServerInstance, source, forward ? DNS_QUERY_AAAA : DNS_QUERY_PTR6, me)
 	{
 		fw = forward;
 	}
@@ -51,9 +51,10 @@ class MyV6Resolver : public Resolver
  */
 class cmd_woot : public command_t
 {
+	Module* Creator;
  public:
 	/* Command 'woot', takes no parameters and needs no special modes */
-	cmd_woot (InspIRCd* Instance) : command_t(Instance,"WOOT", 0, 0)
+	cmd_woot (InspIRCd* Instance, Module* maker) : command_t(Instance,"WOOT", 0, 0), Creator(maker)
 	{
 		this->source = "m_testcommand.so";
 	}
@@ -64,9 +65,9 @@ class cmd_woot : public command_t
 		 * do it for us as required.*/
 		try
 		{
-			MyV6Resolver* r = new MyV6Resolver("shake.stacken.kth.se", true);
+			MyV6Resolver* r = new MyV6Resolver(Creator, "shake.stacken.kth.se", true);
 			ServerInstance->AddResolver(r);
-			r = new MyV6Resolver("2001:6b0:1:ea:202:a5ff:fecd:13a6", false);
+			r = new MyV6Resolver(Creator, "2001:6b0:1:ea:202:a5ff:fecd:13a6", false);
 			ServerInstance->AddResolver(r);
 		}
 		catch (ModuleException& e)
@@ -87,7 +88,7 @@ class ModuleTestCommand : public Module
 	{
 		
 		// Create a new command
-		newcommand = new cmd_woot(ServerInstance);
+		newcommand = new cmd_woot(ServerInstance, this);
 		ServerInstance->AddCommand(newcommand);
 	}