* Cleared up a misconception in the notification mechanism. We already had

methods that used an "event mask" field. There was no need to introduce
  a "flags" field for the same purpose.
* Renamed protected DefaultNotificationService methods (removed "_" prefix).
* Adjusted the code providing a notification service accordingly.
* Changed the event message several notification services generated by renaming
  the "opcode" field to "event".
* Implemented the TEAM_ADDED event and also added a TEAM_EXEC event.
* Added notifications for threads and images.
* Added visitor-like iteration functions for teams, threads, and images.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30126 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/Notifications.h

@@ -118,7 +118,7 @@ private:
 struct default_listener : public DoublyLinkedListLinkImpl<default_listener> {
 	~default_listener();
 
-	uint32	flags;
+	uint32	eventMask;
 	team_id	team;
 	NotificationListener* listener;
 };
@@ -131,7 +131,7 @@ public:
 								DefaultNotificationService(const char* name);
 	virtual						~DefaultNotificationService();
 
-			void				Notify(const KMessage& event, uint32 flags);
+			void				Notify(const KMessage& event, uint32 eventMask);
 
 	virtual status_t			AddListener(const KMessage* eventSpecifier,
 									NotificationListener& listener);
@@ -143,10 +143,10 @@ public:
 	virtual const char*			Name() { return fName; }
 
 protected:
-	virtual status_t			_ToFlags(const KMessage& eventSpecifier,
+	virtual status_t			ToEventMask(const KMessage& eventSpecifier,
-									uint32& flags);
+									uint32& eventMask);
-	virtual	void				_FirstAdded();
+	virtual	void				FirstAdded();
-	virtual	void				_LastRemoved();
+	virtual	void				LastRemoved();
 
 			recursive_lock		fLock;
 			DefaultListenerList	fListeners;
@@ -168,7 +168,7 @@ public:
 									NotificationListener& listener);
 
 			status_t			RemoveUserListeners(port_id port, uint32 token);
-			status_t			UpdateUserListener(uint32 flags,
+			status_t			UpdateUserListener(uint32 eventMask,
 									port_id port, uint32 token);
 
 private:
@@ -176,7 +176,7 @@ private:
 									const KMessage* event);
 	virtual void				AllListenersNotified(
 									NotificationService& service);
-			status_t			_AddListener(uint32 flags,
+			status_t			_AddListener(uint32 eventMask,
 									NotificationListener& listener);
 
 			UserMessagingMessageSender fSender;

headers/private/kernel/kimage.h

@@ -5,12 +5,32 @@
 #ifndef _KERNEL_IMAGE_H
 #define _KERNEL_IMAGE_H
 
-
 #include <image.h>
 
 
+struct image;
 struct team;
 
+#ifdef __cplusplus
+
+#include <util/OpenHashTable.h>
+
+struct image {
+	struct image*			next;
+	struct image*			prev;
+	HashTableLink<image>	hash_link;
+	image_info				info;
+	team_id					team;
+};
+
+#endif	// __cplusplus
+
+// image notifications
+#define IMAGE_MONITOR	'_Im_'
+#define IMAGE_ADDED		0x01
+#define IMAGE_REMOVED	0x02
+
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -20,6 +40,10 @@ extern status_t unregister_image(struct team *team, image_id id);
 extern int32 count_images(struct team *team);
 extern status_t remove_images(struct team *team);
 
+typedef bool (*image_iterator_callback)(struct image* image, void* cookie);
+struct image* image_iterate_through_images(image_iterator_callback callback,
+					void* cookie);
+
 extern status_t image_debug_lookup_user_symbol_address(struct team *team,
 					addr_t address, addr_t *_baseAddress, const char **_symbolName,
 					const char **_imageName, bool *_exactMatch);

headers/private/kernel/port.h

@@ -24,8 +24,8 @@ enum {
 
 // port notifications
 #define PORT_MONITOR	'_Pm_'
-#define PORT_ADDED		1
+#define PORT_ADDED		0x01
-#define PORT_REMOVED	2
+#define PORT_REMOVED	0x02
 
 #ifdef __cplusplus
 extern "C" {

headers/private/kernel/team.h

@@ -9,10 +9,11 @@
 #include <thread_types.h>
 
 
-// Team notifications
+// team notifications
 #define TEAM_MONITOR	'_Tm_'
-#define TEAM_ADDED		1
+#define TEAM_ADDED		0x01
-#define TEAM_REMOVED	2
+#define TEAM_REMOVED	0x02
+#define TEAM_EXEC		0x04
 
 
 #ifdef __cplusplus
@@ -40,6 +41,10 @@ struct team *team_get_team_struct_locked(team_id id);
 int32 team_max_teams(void);
 int32 team_used_teams(void);
 
+typedef bool (*team_iterator_callback)(struct team* team, void* cookie);
+struct team* team_iterate_through_teams(team_iterator_callback callback,
+	void* cookie);
+
 thread_id load_image_etc(int32 argCount, const char* const* args,
 	const char* const* env, int32 priority, team_id parentID, uint32 flags);
 

headers/private/kernel/thread.h

@@ -23,6 +23,12 @@ struct select_info;
 struct thread_creation_attributes;
 
 
+// thread notifications
+#define THREAD_MONITOR	'_tm_'
+#define THREAD_ADDED	0x01
+#define THREAD_REMOVED	0x02
+
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -70,6 +76,10 @@ thread_is_idle_thread(struct thread *thread)
 	return thread->entry == NULL;
 }
 
+typedef bool (*thread_iterator_callback)(struct thread* thread, void* cookie);
+struct thread* thread_iterate_through_threads(thread_iterator_callback callback,
+	void* cookie);
+
 thread_id allocate_thread_id(void);
 thread_id peek_next_thread_id(void);
 

src/add-ons/kernel/network/notifications/notifications.cpp

@@ -27,10 +27,8 @@ public:
 			void			Notify(const KMessage& event);
 
 protected:
-	virtual	status_t		_ToFlags(const KMessage& eventSpecifier,
+	virtual	void			FirstAdded();
-								uint32& flags);
+	virtual	void			LastRemoved();
-	virtual	void			_FirstAdded();
-	virtual	void			_LastRemoved();
 };
 
 static NetNotificationService sNotificationService;
@@ -63,16 +61,8 @@ NetNotificationService::Notify(const KMessage& event)
 }
 
 
-status_t
-NetNotificationService::_ToFlags(const KMessage& eventSpecifier, uint32& flags)
-{
-	flags = eventSpecifier.GetInt32("flags", 0);
-	return B_OK;
-}
-
-
 void
-NetNotificationService::_FirstAdded()
+NetNotificationService::FirstAdded()
 {
 	// The reference counting doesn't work for us, as we'll have to
 	// ensure our module stays loaded.
@@ -82,7 +72,7 @@ NetNotificationService::_FirstAdded()
 
 
 void
-NetNotificationService::_LastRemoved()
+NetNotificationService::LastRemoved()
 {
 	// Give up the reference _AddListener()
 	put_module(NET_NOTIFICATIONS_MODULE_NAME);

src/system/kernel/Notifications.cpp

@@ -13,6 +13,9 @@
 #include <team.h>
 
 
+static const char* kEventMaskString = "event mask";
+
+
 NotificationManager NotificationManager::sManager;
 
 
@@ -158,22 +161,28 @@ DefaultNotificationService::~DefaultNotificationService()
 
 /*!	\brief Notifies all registered listeners.
 	\param event The message defining the event
-	\param flags The flags that must be set in listeners to receive this event
+	\param eventMask Only listeners with an event mask sharing at least one
+		common bit with this mask will receive the event.
 */
 void
-DefaultNotificationService::Notify(const KMessage& event, uint32 flags)
+DefaultNotificationService::Notify(const KMessage& event, uint32 eventMask)
 {
 	RecursiveLocker _(fLock);
 
+	// Note: The following iterations support that the listener removes itself
+	// in the hook method. That's a property of the DoublyLinkedList iterator.
+
+	// notify all listeners about the event
 	DefaultListenerList::Iterator iterator = fListeners.GetIterator();
 	while (default_listener* listener = iterator.Next()) {
-		if ((flags & listener->flags) != 0)
+		if ((eventMask & listener->eventMask) != 0)
 			listener->listener->EventOccured(*this, &event);
 	}
 
+	// notify all listeners that all listeners have been notified
 	iterator = fListeners.GetIterator();
 	while (default_listener* listener = iterator.Next()) {
-		if ((flags & listener->flags) != 0)
+		if ((eventMask & listener->eventMask) != 0)
 			listener->listener->AllListenersNotified(*this);
 	}
 }
@@ -186,8 +195,8 @@ DefaultNotificationService::AddListener(const KMessage* eventSpecifier,
 	if (eventSpecifier == NULL)
 		return B_BAD_VALUE;
 
-	uint32 flags;
+	uint32 eventMask;
-	status_t status = _ToFlags(*eventSpecifier, flags);
+	status_t status = ToEventMask(*eventSpecifier, eventMask);
 	if (status != B_OK)
 		return status;
 
@@ -195,13 +204,13 @@ DefaultNotificationService::AddListener(const KMessage* eventSpecifier,
 	if (listener == NULL)
 		return B_NO_MEMORY;
 
-	listener->flags = flags;
+	listener->eventMask = eventMask;
 	listener->team = -1;
 	listener->listener = &notificationListener;
 
 	RecursiveLocker _(fLock);
 	if (fListeners.IsEmpty())
-		_FirstAdded();
+		FirstAdded();
 	fListeners.Add(listener);
 
 	return B_OK;
@@ -227,9 +236,9 @@ DefaultNotificationService::RemoveListener(const KMessage* eventSpecifier,
 		if (listener->listener == &notificationListener) {
 			iterator.Remove();
 			delete listener;
-			
+
 			if (fListeners.IsEmpty())
-				_LastRemoved();
+				LastRemoved();
 			return B_OK;
 		}
 	}
@@ -239,21 +248,21 @@ DefaultNotificationService::RemoveListener(const KMessage* eventSpecifier,
 
 
 status_t
-DefaultNotificationService::_ToFlags(const KMessage& eventSpecifier,
+DefaultNotificationService::ToEventMask(const KMessage& eventSpecifier,
-	uint32& flags)
+	uint32& eventMask)
 {
-	return eventSpecifier.FindInt32("flags", (int32*)&flags);
+	return eventSpecifier.FindInt32("event mask", (int32*)&eventMask);
 }
 
 
 void
-DefaultNotificationService::_FirstAdded()
+DefaultNotificationService::FirstAdded()
 {
 }
 
 
 void
-DefaultNotificationService::_LastRemoved()
+DefaultNotificationService::LastRemoved()
 {
 }
 
@@ -281,9 +290,9 @@ DefaultUserNotificationService::AddListener(const KMessage* eventSpecifier,
 	if (eventSpecifier == NULL)
 		return B_BAD_VALUE;
 
-	uint32 flags = eventSpecifier->GetInt32("flags", 0);
+	uint32 eventMask = eventSpecifier->GetInt32(kEventMaskString, 0);
 
-	return _AddListener(flags, listener);
+	return _AddListener(eventMask, listener);
 }
 
 
@@ -294,18 +303,18 @@ DefaultUserNotificationService::UpdateListener(const KMessage* eventSpecifier,
 	if (eventSpecifier == NULL)
 		return B_BAD_VALUE;
 
-	uint32 flags = eventSpecifier->GetInt32("flags", 0);
+	uint32 eventMask = eventSpecifier->GetInt32(kEventMaskString, 0);
-	bool addFlags = eventSpecifier->GetBool("add flags", false);
+	bool addEvents = eventSpecifier->GetBool("add events", false);
 
 	RecursiveLocker _(fLock);
 
 	DefaultListenerList::Iterator iterator = fListeners.GetIterator();
 	while (default_listener* listener = iterator.Next()) {
 		if (*listener->listener == notificationListener) {
-			if (addFlags)
+			if (addEvents)
-				listener->flags |= flags;
+				listener->eventMask |= eventMask;
 			else
-				listener->flags = flags;
+				listener->eventMask = eventMask;
 			return B_OK;
 		}
 	}
@@ -345,9 +354,9 @@ DefaultUserNotificationService::RemoveUserListeners(port_id port, uint32 token)
 		if (*listener->listener == userListener) {
 			iterator.Remove();
 			delete listener;
-			
+
 			if (fListeners.IsEmpty())
-				_LastRemoved();
+				LastRemoved();
 			return B_OK;
 		}
 	}
@@ -357,8 +366,8 @@ DefaultUserNotificationService::RemoveUserListeners(port_id port, uint32 token)
 
 
 status_t
-DefaultUserNotificationService::UpdateUserListener(uint32 flags, port_id port,
+DefaultUserNotificationService::UpdateUserListener(uint32 eventMask,
-	uint32 token)
+	port_id port, uint32 token)
 {
 	UserMessagingListener userListener(fSender, port, token);
 
@@ -367,7 +376,7 @@ DefaultUserNotificationService::UpdateUserListener(uint32 flags, port_id port,
 	DefaultListenerList::Iterator iterator = fListeners.GetIterator();
 	while (default_listener* listener = iterator.Next()) {
 		if (*listener->listener == userListener) {
-			listener->flags |= flags;
+			listener->eventMask |= eventMask;
 			return B_OK;
 		}
 	}
@@ -377,7 +386,7 @@ DefaultUserNotificationService::UpdateUserListener(uint32 flags, port_id port,
 	if (copiedListener == NULL)
 		return B_NO_MEMORY;
 
-	status_t status = _AddListener(flags, *copiedListener);
+	status_t status = _AddListener(eventMask, *copiedListener);
 	if (status != B_OK)
 		delete copiedListener;
 
@@ -389,13 +398,13 @@ void
 DefaultUserNotificationService::EventOccured(NotificationService& service,
 	const KMessage* event)
 {
-	int32 opcode = event->GetInt32("opcode", -1);
+	int32 eventCode = event->GetInt32("event", -1);
 	team_id team = event->GetInt32("team", -1);
 
-	if (opcode == TEAM_REMOVED && team >= B_OK) {
+	if (eventCode == TEAM_REMOVED && team >= B_OK) {
 		// check if we have any listeners from that team, and remove them
 		RecursiveLocker _(fLock);
-	
+
 		DefaultListenerList::Iterator iterator = fListeners.GetIterator();
 		while (default_listener* listener = iterator.Next()) {
 			if (listener->team == team) {
@@ -415,20 +424,20 @@ DefaultUserNotificationService::AllListenersNotified(
 
 
 status_t
-DefaultUserNotificationService::_AddListener(uint32 flags,
+DefaultUserNotificationService::_AddListener(uint32 eventMask,
 	NotificationListener& notificationListener)
 {
 	default_listener* listener = new(std::nothrow) default_listener;
 	if (listener == NULL)
 		return B_NO_MEMORY;
 
-	listener->flags = flags;
+	listener->eventMask = eventMask;
 	listener->team = team_get_current_team_id();
 	listener->listener = &notificationListener;
 
 	RecursiveLocker _(fLock);
 	if (fListeners.IsEmpty())
-		_FirstAdded();
+		FirstAdded();
 	fListeners.Add(listener);
 
 	return B_OK;
@@ -511,7 +520,7 @@ NotificationManager::AddListener(const char* serviceName,
 	char buffer[96];
 	KMessage specifier;
 	specifier.SetTo(buffer, sizeof(buffer), 0);
-	specifier.AddInt32("event mask", eventMask);
+	specifier.AddInt32(kEventMaskString, eventMask);
 
 	return AddListener(serviceName, &specifier, listener);
 }
@@ -540,7 +549,7 @@ NotificationManager::UpdateListener(const char* serviceName,
 	char buffer[96];
 	KMessage specifier;
 	specifier.SetTo(buffer, sizeof(buffer), 0);
-	specifier.AddInt32("event mask", eventMask);
+	specifier.AddInt32(kEventMaskString, eventMask);
 
 	return UpdateListener(serviceName, &specifier, listener);
 }

src/system/kernel/disk_device_manager/KDiskDeviceManager.cpp

@@ -195,13 +195,6 @@ public:
 	virtual ~DiskNotifications()
 	{
 	}
-
-protected:
-	status_t _ToFlags(const KMessage& eventSpecifier, uint32& flags)
-	{
-		flags = eventSpecifier.GetInt32("flags", 0);
-		return B_OK;
-	}
 };
 
 

src/system/kernel/image.cpp

@@ -12,11 +12,12 @@
 #include <kimage.h>
 #include <kscheduler.h>
 #include <lock.h>
+#include <Notifications.h>
 #include <team.h>
 #include <thread.h>
 #include <thread_types.h>
 #include <user_debugger.h>
-#include <util/OpenHashTable.h>
+#include <util/AutoLock.h>
 
 #include <stdlib.h>
 #include <string.h>
@@ -31,14 +32,6 @@
 
 #define ADD_DEBUGGER_COMMANDS
 
-struct image {
-	struct image*			next;
-	struct image*			prev;
-	HashTableLink<image>	hash_link;
-	image_info				info;
-	team_id					team;
-};
-
 
 struct ImageTableDefinition {
 	typedef image_id		KeyType;
@@ -55,9 +48,31 @@ struct ImageTableDefinition {
 typedef OpenHashTable<ImageTableDefinition> ImageTable;
 
 
+class ImageNotificationService : public DefaultNotificationService {
+public:
+	ImageNotificationService()
+		: DefaultNotificationService("images")
+	{
+	}
+
+	void Notify(uint32 eventCode, struct image* image)
+	{
+		char eventBuffer[128];
+		KMessage event;
+		event.SetTo(eventBuffer, sizeof(eventBuffer), IMAGE_MONITOR);
+		event.AddInt32("event", eventCode);
+		event.AddInt32("image", image->info.id);
+		event.AddPointer("imageStruct", image);
+
+		DefaultNotificationService::Notify(event, eventCode);
+	}
+};
+
+
 static image_id sNextImageID = 1;
 static mutex sImageMutex = MUTEX_INITIALIZER("image");
 static ImageTable* sImageTable;
+static ImageNotificationService sNotificationService;
 
 
 /*!	Registers an image with the specified team.
@@ -87,6 +102,9 @@ register_image(struct team *team, image_info *_info, size_t size)
 		list_add_item(&team->image_list, image);
 	sImageTable->Insert(image);
 
+	// notify listeners
+	sNotificationService.Notify(IMAGE_ADDED, image);
+
 	mutex_unlock(&sImageMutex);
 
 	TRACE(("register_image(team = %p, image id = %ld, image = %p\n", team, id, image));
@@ -116,6 +134,9 @@ unregister_image(struct team *team, image_id id)
 		// notify the debugger
 		user_debug_image_deleted(&image->info);
 
+		// notify listeners
+		sNotificationService.Notify(IMAGE_REMOVED, image);
+
 		free(image);
 	}
 
@@ -263,6 +284,22 @@ dump_images_list(int argc, char **argv)
 #endif
 
 
+struct image*
+image_iterate_through_images(image_iterator_callback callback, void* cookie)
+{
+	MutexLocker locker(sImageMutex);
+
+	ImageTable::Iterator it = sImageTable->GetIterator();
+	struct image* image = NULL;
+	while ((image = it.Next()) != NULL) {
+		if (callback(image, cookie))
+			break;
+	}
+
+	return image;
+}
+
+
 status_t
 image_debug_lookup_user_symbol_address(struct team *team, addr_t address,
 	addr_t *_baseAddress, const char **_symbolName, const char **_imageName,
@@ -310,6 +347,8 @@ image_init(void)
 		return error;
 	}
 
+	new(&sNotificationService) ImageNotificationService();
+
 #ifdef ADD_DEBUGGER_COMMANDS
 	add_debugger_command("team_images", &dump_images_list, "Dump all registered images from the current team");
 #endif

src/system/kernel/port.cpp

@@ -65,10 +65,6 @@ public:
 							PortNotificationService();
 
 			void			Notify(uint32 opcode, port_id team);
-
-protected:
-	virtual	status_t		_ToFlags(const KMessage& eventSpecifier,
-								uint32& flags);
 };
 
 #define MAX_QUEUE_LENGTH 4096
@@ -109,18 +105,10 @@ PortNotificationService::Notify(uint32 opcode, port_id port)
 	char eventBuffer[64];
 	KMessage event;
 	event.SetTo(eventBuffer, sizeof(eventBuffer), PORT_MONITOR);
-	event.AddInt32("opcode", opcode);
+	event.AddInt32("event", opcode);
 	event.AddInt32("port", port);
 
-	DefaultNotificationService::Notify(event, ~0U);
+	DefaultNotificationService::Notify(event, opcode);
-}
-
-
-status_t
-PortNotificationService::_ToFlags(const KMessage& eventSpecifier, uint32& flags)
-{
-	flags = ~0U;
-	return B_OK;
 }
 
 

src/system/kernel/team.cpp

@@ -86,11 +86,7 @@ class TeamNotificationService : public DefaultNotificationService {
 public:
 							TeamNotificationService();
 
-			void			Notify(uint32 opcode, team_id team);
+			void			Notify(uint32 eventCode, struct team* team);
-
-protected:
-	virtual	status_t		_ToFlags(const KMessage& eventSpecifier,
-								uint32& flags);
 };
 
 
@@ -312,23 +308,16 @@ TeamNotificationService::TeamNotificationService()
 
 
 void
-TeamNotificationService::Notify(uint32 opcode, team_id team)
+TeamNotificationService::Notify(uint32 eventCode, struct team* team)
 {
-	char eventBuffer[64];
+	char eventBuffer[128];
 	KMessage event;
 	event.SetTo(eventBuffer, sizeof(eventBuffer), TEAM_MONITOR);
-	event.AddInt32("opcode", opcode);
+	event.AddInt32("event", eventCode);
-	event.AddInt32("team", team);
+	event.AddInt32("team", team->id);
+	event.AddPointer("teamStruct", team);
 
-	DefaultNotificationService::Notify(event, ~0U);
+	DefaultNotificationService::Notify(event, eventCode);
-}
-
-
-status_t
-TeamNotificationService::_ToFlags(const KMessage& eventSpecifier, uint32& flags)
-{
-	flags = ~0U;
-	return B_OK;
 }
 
 
@@ -1236,6 +1225,9 @@ load_image_internal(char**& _flatArgs, size_t flatArgsSize, int32 argCount,
 	if (status != B_OK)
 		goto err4;
 
+	// notify team listeners
+	sNotificationService.Notify(TEAM_ADDED, team);
+
 	// Create a kernel thread, but under the context of the new team
 	// The new thread will take over ownership of teamArgs
 	thread = spawn_kernel_thread_etc(team_create_thread_start, threadName,
@@ -1430,6 +1422,9 @@ exec_team(const char *path, char**& _flatArgs, size_t flatArgsSize,
 
 	user_debug_team_exec();
 
+	// notify team listeners
+	sNotificationService.Notify(TEAM_EXEC, team);
+
 	status = team_create_thread_start(teamArgs);
 		// this one usually doesn't return...
 
@@ -1603,6 +1598,9 @@ fork_team(void)
 			goto err5;
 	}
 
+	// notify team listeners
+	sNotificationService.Notify(TEAM_ADDED, team);
+
 	// create a kernel thread under the context of the new team
 	threadID = spawn_kernel_thread_etc(fork_team_thread_start,
 		parentThread->name, parentThread->priority, forkArgs,
@@ -2084,6 +2082,26 @@ team_used_teams(void)
 }
 
 
+/*!	Iterates through the list of teams. The team spinlock must be held.
+ */
+struct team*
+team_iterate_through_teams(team_iterator_callback callback, void* cookie)
+{
+	struct hash_iterator iterator;
+	hash_open(sTeamHash, &iterator);
+
+	struct team* team;
+	while ((team = (struct team*)hash_next(sTeamHash, &iterator)) != NULL) {
+		if (callback(team, cookie))
+			break;
+	}
+
+	hash_close(sTeamHash, &iterator, false);
+
+	return team;
+}
+
+
 /*! Fills the provided death entry if it's in the team.
 	You need to have the team lock held when calling this function.
 */
@@ -2420,7 +2438,7 @@ team_delete_team(struct team *team)
 		}
 	}
 
-	sNotificationService.Notify(TEAM_REMOVED, team->id);
+	sNotificationService.Notify(TEAM_REMOVED, team);
 
 	// free team resources
 

src/system/kernel/thread.cpp

@@ -30,6 +30,7 @@
 #include <kimage.h>
 #include <kscheduler.h>
 #include <ksignal.h>
+#include <Notifications.h>
 #include <real_time_clock.h>
 #include <smp.h>
 #include <syscalls.h>
@@ -86,8 +87,32 @@ struct UndertakerEntry : DoublyLinkedListLinkImpl<UndertakerEntry> {
 	}
 };
 
+
+class ThreadNotificationService : public DefaultNotificationService {
+public:
+	ThreadNotificationService()
+		: DefaultNotificationService("threads")
+	{
+	}
+
+	void Notify(uint32 eventCode, struct thread* thread)
+	{
+		char eventBuffer[128];
+		KMessage event;
+		event.SetTo(eventBuffer, sizeof(eventBuffer), THREAD_MONITOR);
+		event.AddInt32("event", eventCode);
+		event.AddInt32("thread", thread->id);
+		event.AddPointer("threadStruct", thread);
+
+		DefaultNotificationService::Notify(event, eventCode);
+	}
+};
+
+
 static DoublyLinkedList<UndertakerEntry> sUndertakerEntries;
 static ConditionVariable sUndertakerCondition;
+static ThreadNotificationService sNotificationService;
+
 
 // The dead queue is used as a pool from which to retrieve and reuse previously
 // allocated thread structs when creating a new thread. It should be gone once
@@ -504,6 +529,9 @@ create_thread(thread_creation_attributes& attributes, bool kernel)
 	thread->entry = attributes.entry;
 	status = thread->id;
 
+	// notify listeners
+	sNotificationService.Notify(THREAD_ADDED, thread);
+
 	if (kernel) {
 		// this sets up an initial kthread stack that runs the entry
 
@@ -1507,6 +1535,9 @@ thread_exit(void)
 		put_select_sync(sync);
 	}
 
+	// notify listeners
+	sNotificationService.Notify(THREAD_REMOVED, thread);
+
 	// shutdown the thread messaging
 
 	status = acquire_sem_etc(thread->msg.write_sem, 1, B_RELATIVE_TIMEOUT, 0);
@@ -1740,6 +1771,25 @@ thread_dequeue_id(struct thread_queue *q, thread_id id)
 }
 
 
+struct thread*
+thread_iterate_through_threads(thread_iterator_callback callback, void* cookie)
+{
+	struct hash_iterator iterator;
+	hash_open(sThreadHash, &iterator);
+
+	struct thread* thread;
+	while ((thread = (struct thread*)hash_next(sThreadHash, &iterator))
+			!= NULL) {
+		if (callback(thread, cookie))
+			break;
+	}
+
+	hash_close(sThreadHash, &iterator, false);
+
+	return thread;
+}
+
+
 thread_id
 allocate_thread_id(void)
 {
@@ -2099,6 +2149,9 @@ thread_init(kernel_args *args)
 	}
 	sUsedThreads = args->num_cpus;
 
+	// init the notification service
+	new(&sNotificationService) ThreadNotificationService();
+
 	// start the undertaker thread
 	new(&sUndertakerEntries) DoublyLinkedList<UndertakerEntry>();
 	sUndertakerCondition.Init(&sUndertakerEntries, "undertaker entries");