r23055: Rewrite messages.c to use auto-generated marshalling in the tdb. I'm

doing this because for the clustering the marshalling is needed in more
than one place, so I wanted a decent routine to marshall a message_rec
struct which was not there before.

Tridge, this seems about the same speed as it used to be before, the
librpc/ndr overhead in my tests was under the noise.

Volker
(This used to be commit eaefd00563173dfabb7716c5695ac0a2f7139bb6)

1 files changed, 267 insertions, 330 deletions

diff --git a/source3/lib/messages.c b/source3/lib/messages.c
index 95f4aba4e7..6932369b21 100644
--- a/source3/lib/messages.c
+++ b/source3/lib/messages.c
@@ -47,54 +47,30 @@
 */
 
 #include "includes.h"
+#include "librpc/gen_ndr/messaging.h"
+#include "librpc/gen_ndr/ndr_messaging.h"
 
 /* the locking database handle */
-static TDB_CONTEXT *tdb;
 static int received_signal;
 
 /* change the message version with any incompatible changes in the protocol */
-#define MESSAGE_VERSION 1
+#define MESSAGE_VERSION 2
 
-struct message_rec {
-	int msg_version;
-	int msg_type;
-	struct server_id dest;
-	struct server_id src;
-	size_t len;
-};
-
-/* we have a linked list of dispatch handlers */
-static struct dispatch_fns {
-	struct dispatch_fns *next, *prev;
-	int msg_type;
-	void (*fn)(int msg_type, struct server_id pid, void *buf, size_t len,
-		   void *private_data);
+struct messaging_callback {
+	struct messaging_callback *prev, *next;
+	uint32 msg_type;
+	void (*fn)(struct messaging_context *msg, void *private_data, 
+		   uint32_t msg_type, 
+		   struct server_id server_id, DATA_BLOB *data);
 	void *private_data;
-} *dispatch_fns;
-
-static void message_register(int msg_type, 
-			     void (*fn)(int msg_type, struct server_id pid,
-					void *buf, size_t len,
-					void *private_data),
-			     void *private_data);
-
-/****************************************************************************
- Free global objects.
-****************************************************************************/
+};
 
-void gfree_messages(void)
-{
-	struct dispatch_fns *dfn, *next;
-
-	/* delete the dispatch_fns list */
-	dfn = dispatch_fns;
-	while( dfn ) {
-		next = dfn->next;
-		DLIST_REMOVE(dispatch_fns, dfn);
-		SAFE_FREE(dfn);
-		dfn = next;
-	}
-}
+struct messaging_context {
+	TDB_CONTEXT *tdb;
+	struct server_id id;
+	struct event_context *event_ctx;
+	struct messaging_callback *callbacks;
+};
 
 /****************************************************************************
  Notifications come in as signals.
@@ -106,21 +82,25 @@ static void sig_usr1(void)
 	sys_select_signal(SIGUSR1);
 }
 
-static NTSTATUS message_send_pid(struct server_id pid, int msg_type,
-				 const void *buf, size_t len);
+static NTSTATUS messaging_tdb_send(TDB_CONTEXT *msg_tdb,
+				   struct server_id pid, int msg_type,
+				   const void *buf, size_t len);
 
 /****************************************************************************
  A useful function for testing the message system.
 ****************************************************************************/
 
-static void ping_message(int msg_type, struct server_id src,
-			 void *buf, size_t len, void *private_data)
+static void ping_message(struct messaging_context *msg_ctx,
+			 void *private_data,
+			 uint32_t msg_type,
+			 struct server_id src,
+			 DATA_BLOB *data)
 {
-	const char *msg = buf ? (const char *)buf : "none";
+	const char *msg = data->data ? (const char *)data->data : "none";
 
 	DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
 		 procid_str_static(&src), msg));
-	message_send_pid(src, MSG_PONG, buf, len);
+	messaging_send(msg_ctx, src, MSG_PONG, data);
 }
 
 /****************************************************************************
@@ -131,24 +111,21 @@ static BOOL message_init(struct messaging_context *msg_ctx)
 {
 	sec_init();
 
-	if (tdb)
-		return True;
-
-	tdb = tdb_open_log(lock_path("messages.tdb"), 
-		       0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
-		       O_RDWR|O_CREAT,0600);
+	msg_ctx->tdb = tdb_open_log(lock_path("messages.tdb"), 
+				    0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
+				    O_RDWR|O_CREAT,0600);
 
-	if (!tdb) {
+	if (!msg_ctx->tdb) {
 		DEBUG(0,("ERROR: Failed to initialise messages database\n"));
 		return False;
 	}
 
 	/* Activate the per-hashchain freelist */
-	tdb_set_max_dead(tdb, 5);
+	tdb_set_max_dead(msg_ctx->tdb, 5);
 
 	CatchSignal(SIGUSR1, SIGNAL_CAST sig_usr1);
 
-	message_register(MSG_PING, ping_message, NULL);
+	messaging_register(msg_ctx, NULL, MSG_PING, ping_message);
 
 	/* Register some debugging related messages */
 
@@ -175,6 +152,99 @@ static TDB_DATA message_key_pid(struct server_id pid)
 	return kbuf;
 }
 
+/*
+  Fetch the messaging array for a process
+ */
+
+static NTSTATUS messaging_tdb_fetch(TDB_CONTEXT *msg_tdb,
+				    TDB_DATA key,
+				    TALLOC_CTX *mem_ctx,
+				    struct messaging_array **presult)
+{
+	struct messaging_array *result;
+	TDB_DATA data;
+	DATA_BLOB blob;
+	NTSTATUS status;
+
+	if (!(result = TALLOC_ZERO_P(mem_ctx, struct messaging_array))) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	data = tdb_fetch(msg_tdb, key);
+
+	if (data.dptr == NULL) {
+		*presult = result;
+		return NT_STATUS_OK;
+	}
+
+	blob = data_blob_const(data.dptr, data.dsize);
+
+	status = ndr_pull_struct_blob(
+		&blob, result, result,
+		(ndr_pull_flags_fn_t)ndr_pull_messaging_array);
+
+	SAFE_FREE(data.dptr);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(result);
+		return status;
+	}
+
+	if (DEBUGLEVEL >= 10) {
+		DEBUG(10, ("messaging_tdb_fetch:\n"));
+		NDR_PRINT_DEBUG(messaging_array, result);
+	}
+
+	*presult = result;
+	return NT_STATUS_OK;
+}
+
+/*
+  Store a messaging array for a pid
+*/
+
+static NTSTATUS messaging_tdb_store(TDB_CONTEXT *msg_tdb,
+				    TDB_DATA key,
+				    struct messaging_array *array)
+{
+	TDB_DATA data;
+	DATA_BLOB blob;
+	NTSTATUS status;
+	TALLOC_CTX *mem_ctx;
+	int ret;
+
+	if (array->num_messages == 0) {
+		tdb_delete(msg_tdb, key);
+		return NT_STATUS_OK;
+	}
+
+	if (!(mem_ctx = talloc_new(array))) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	status = ndr_push_struct_blob(
+		&blob, mem_ctx, array,
+		(ndr_push_flags_fn_t)ndr_push_messaging_array);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(mem_ctx);
+		return status;
+	}
+
+	if (DEBUGLEVEL >= 10) {
+		DEBUG(10, ("messaging_tdb_store:\n"));
+		NDR_PRINT_DEBUG(messaging_array, array);
+	}
+
+	data.dptr = blob.data;
+	data.dsize = blob.length;
+
+	ret = tdb_store(msg_tdb, key, data, TDB_REPLACE);
+	TALLOC_FREE(mem_ctx);
+
+	return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION;
+}
+
 /****************************************************************************
  Notify a process that it has a message. If the process doesn't exist 
  then delete its record in the database.
@@ -216,17 +286,6 @@ static NTSTATUS message_notify(struct server_id procid)
 	 * Something has gone wrong
 	 */
 
-	if (errno == ESRCH) {
-		DEBUG(2,("pid %d doesn't exist - deleting messages record\n",
-			 (int)pid));
-		tdb_delete(tdb, message_key_pid(procid));
-
-		/*
-		 * INVALID_HANDLE is the closest I can think of -- vl
-		 */
-		return NT_STATUS_INVALID_HANDLE;
-	}
-
 	DEBUG(2,("message to process %d failed - %s\n", (int)pid,
 		 strerror(errno)));
 
@@ -235,6 +294,7 @@ static NTSTATUS message_notify(struct server_id procid)
 	 * errormap.o into lots of utils.
 	 */
 
+	if (errno == ESRCH)  return NT_STATUS_INVALID_HANDLE;
 	if (errno == EINVAL) return NT_STATUS_INVALID_PARAMETER;
 	if (errno == EPERM)  return NT_STATUS_ACCESS_DENIED;
 	return NT_STATUS_UNSUCCESSFUL;
@@ -244,12 +304,15 @@ static NTSTATUS message_notify(struct server_id procid)
  Send a message to a particular pid.
 ****************************************************************************/
 
-static NTSTATUS message_send_pid(struct server_id pid, int msg_type,
-				 const void *buf, size_t len)
+static NTSTATUS messaging_tdb_send(TDB_CONTEXT *msg_tdb,
+				   struct server_id pid, int msg_type,
+				   const void *buf, size_t len)
 {
-	TDB_DATA dbuf;
-	struct message_rec rec;
-	int ret;
+	struct messaging_array *msg_array;
+	struct messaging_rec *rec;
+	TALLOC_CTX *mem_ctx;
+	NTSTATUS status;
+	TDB_DATA key = message_key_pid(pid);
 
 	/* NULL pointer means implicit length zero. */
 	if (!buf) {
@@ -263,138 +326,129 @@ static NTSTATUS message_send_pid(struct server_id pid, int msg_type,
 
 	SMB_ASSERT(procid_to_pid(&pid) > 0);
 
-	rec.msg_version = MESSAGE_VERSION;
-	rec.msg_type = msg_type;
-	rec.dest = pid;
-	rec.src = procid_self();
-	rec.len = buf ? len : 0;
+	if (!(mem_ctx = talloc_init("message_send_pid"))) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (tdb_chainlock(msg_tdb, key) == -1) {
+		return NT_STATUS_LOCK_NOT_GRANTED;
+	}
+
+	status = messaging_tdb_fetch(msg_tdb, key, mem_ctx, &msg_array);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		tdb_chainunlock(msg_tdb, key);
+		TALLOC_FREE(mem_ctx);
+		return status;
+	}
 
-	dbuf.dptr = (uint8 *)SMB_MALLOC(len + sizeof(rec));
-	if (!dbuf.dptr) {
+	if (!(rec = TALLOC_REALLOC_ARRAY(mem_ctx, msg_array->messages,
+					 struct messaging_rec,
+					 msg_array->num_messages+1))) {
+		tdb_chainunlock(msg_tdb, key);
+		TALLOC_FREE(mem_ctx);
 		return NT_STATUS_NO_MEMORY;
 	}
 
-	memcpy(dbuf.dptr, &rec, sizeof(rec));
-	if (len > 0 && buf)
-		memcpy((void *)((char*)dbuf.dptr+sizeof(rec)), buf, len);
+	rec[msg_array->num_messages].msg_version = MESSAGE_VERSION;
+	rec[msg_array->num_messages].msg_type = msg_type;
+	rec[msg_array->num_messages].dest = pid;
+	rec[msg_array->num_messages].src = procid_self();
+	rec[msg_array->num_messages].buf = data_blob_const(buf, len);
 
-	dbuf.dsize = len + sizeof(rec);
+	msg_array->messages = rec;
+	msg_array->num_messages += 1;
 
-	ret = tdb_append(tdb, message_key_pid(pid), dbuf);
+	status = messaging_tdb_store(msg_tdb, key, msg_array);
 
-	SAFE_FREE(dbuf.dptr);
+	tdb_chainunlock(msg_tdb, key);
+	TALLOC_FREE(mem_ctx);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+	
+	status = message_notify(pid);
 
-	if (ret == -1) {
-		return NT_STATUS_INTERNAL_ERROR;
+	if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
+		DEBUG(2, ("pid %s doesn't exist - deleting messages record\n",
+			  procid_str_static(&pid)));
+		tdb_delete(msg_tdb, message_key_pid(pid));
 	}
 
-	errno = 0;                    /* paranoia */
-	return message_notify(pid);
+	return status;
 }
 
 /****************************************************************************
  Count the messages pending for a particular pid. Expensive....
 ****************************************************************************/
 
-unsigned int messages_pending_for_pid(struct server_id pid)
+unsigned int messages_pending_for_pid(struct messaging_context *msg_ctx,
+				      struct server_id pid)
 {
-	TDB_DATA dbuf;
-	uint8 *buf;
-	unsigned int message_count = 0;
+	struct messaging_array *msg_array;
+	unsigned int result;
 
-	dbuf = tdb_fetch(tdb, message_key_pid(pid));
-	if (dbuf.dptr == NULL || dbuf.dsize == 0) {
-		SAFE_FREE(dbuf.dptr);
+	if (!NT_STATUS_IS_OK(messaging_tdb_fetch(msg_ctx->tdb,
+						 message_key_pid(pid), NULL,
+						 &msg_array))) {
+		DEBUG(10, ("messaging_tdb_fetch failed\n"));
 		return 0;
 	}
 
-	for (buf = dbuf.dptr; dbuf.dsize > sizeof(struct message_rec);) {
-		struct message_rec rec;
-		memcpy(&rec, buf, sizeof(rec));
-		buf += (sizeof(rec) + rec.len);
-		dbuf.dsize -= (sizeof(rec) + rec.len);
-		message_count++;
-	}
-
-	SAFE_FREE(dbuf.dptr);
-	return message_count;
-}
+	result = msg_array->num_messages;
+	TALLOC_FREE(msg_array);
+	return result;
+}	
 
 /****************************************************************************
  Retrieve all messages for the current process.
 ****************************************************************************/
 
-static BOOL retrieve_all_messages(char **msgs_buf, size_t *total_len)
+static NTSTATUS retrieve_all_messages(TDB_CONTEXT *msg_tdb,
+				      TALLOC_CTX *mem_ctx,
+				      struct messaging_array **presult)
 {
-	TDB_DATA kbuf;
-	TDB_DATA dbuf;
-	TDB_DATA null_dbuf;
-
-	ZERO_STRUCT(null_dbuf);
-
-	*msgs_buf = NULL;
-	*total_len = 0;
+	struct messaging_array *result;
+	TDB_DATA key = message_key_pid(procid_self());
+	NTSTATUS status;
 
-	kbuf = message_key_pid(procid_self());
+	if (tdb_chainlock(msg_tdb, key) == -1) {
+		return NT_STATUS_LOCK_NOT_GRANTED;
+	}
 
-	if (tdb_chainlock(tdb, kbuf) == -1)
-		return False;
+	status = messaging_tdb_fetch(msg_tdb, key, mem_ctx, &result);
 
-	dbuf = tdb_fetch(tdb, kbuf);
 	/*
-	 * Replace with an empty record to keep the allocated
-	 * space in the tdb.
+	 * We delete the record here, tdb_set_max_dead keeps it around
 	 */
-	tdb_store(tdb, kbuf, null_dbuf, TDB_REPLACE);
-	tdb_chainunlock(tdb, kbuf);
+	tdb_delete(msg_tdb, key);
+	tdb_chainunlock(msg_tdb, key);
 
-	if (dbuf.dptr == NULL || dbuf.dsize == 0) {
-		SAFE_FREE(dbuf.dptr);
-		return False;
+	if (NT_STATUS_IS_OK(status)) {
+		*presult = result;
 	}
 
-	*msgs_buf = (char *)dbuf.dptr;
-	*total_len = dbuf.dsize;
-
-	return True;
+	return status;
 }
 
-/****************************************************************************
- Parse out the next message for the current process.
-****************************************************************************/
-
-static BOOL message_recv(char *msgs_buf, size_t total_len, int *msg_type,
-			 struct server_id *src, char **buf, size_t *len)
+/*
+  Dispatch one messsaging_rec
+*/
+static void messaging_dispatch_rec(struct messaging_context *msg_ctx,
+				   struct messaging_rec *rec)
 {
-	struct message_rec rec;
-	char *ret_buf = *buf;
-
-	*buf = NULL;
-	*len = 0;
-
-	if (total_len - (ret_buf - msgs_buf) < sizeof(rec))
-		return False;
-
-	memcpy(&rec, ret_buf, sizeof(rec));
-	ret_buf += sizeof(rec);
-
-	if (rec.msg_version != MESSAGE_VERSION) {
-		DEBUG(0,("message version %d received (expected %d)\n",
-			 rec.msg_version, MESSAGE_VERSION));
-		return False;
-	}
+	struct messaging_callback *cb, *next;
 
-	if (rec.len > 0) {
-		if (total_len - (ret_buf - msgs_buf) < rec.len)
-			return False;
+	for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
+		next = cb->next;
+		if (cb->msg_type == rec->msg_type) {
+			cb->fn(msg_ctx, cb->private_data, rec->msg_type,
+			       rec->src, &rec->buf);
+			return;
+		}
 	}
-
-	*len = rec.len;
-	*msg_type = rec.msg_type;
-	*src = rec.src;
-	*buf = ret_buf;
-
-	return True;
+	return;
 }
 
 /****************************************************************************
@@ -404,14 +458,10 @@ static BOOL message_recv(char *msgs_buf, size_t total_len, int *msg_type,
  messages on an *odd* byte boundary.
 ****************************************************************************/
 
-void message_dispatch(void)
+void message_dispatch(struct messaging_context *msg_ctx)
 {
-	int msg_type;
-	struct server_id src;
-	char *buf;
-	char *msgs_buf;
-	size_t len, total_len;
-	int n_handled;
+	struct messaging_array *msg_array = NULL;
+	uint32 i;
 
 	if (!received_signal)
 		return;
@@ -421,37 +471,16 @@ void message_dispatch(void)
 
 	received_signal = 0;
 
-	if (!retrieve_all_messages(&msgs_buf, &total_len))
+	if (!NT_STATUS_IS_OK(retrieve_all_messages(msg_ctx->tdb, NULL,
+						   &msg_array))) {
 		return;
+	}
 
-	for (buf = msgs_buf;
-	     message_recv(msgs_buf, total_len, &msg_type, &src, &buf, &len);
-	     buf += len) {
-		struct dispatch_fns *dfn;
-
-		DEBUG(10,("message_dispatch: received msg_type=%d "
-			  "src_pid=%u\n", msg_type,
-			  (unsigned int) procid_to_pid(&src)));
-
-		n_handled = 0;
-		for (dfn = dispatch_fns; dfn; dfn = dfn->next) {
-			if (dfn->msg_type == msg_type) {
-				DEBUG(10,("message_dispatch: processing "
-					  "message of type %d.\n", msg_type));
-				dfn->fn(msg_type, src,
-					len ? (void *)buf : NULL, len,
-					dfn->private_data);
-				n_handled++;
-				break;
-			}
-		}
-		if (!n_handled) {
-			DEBUG(5,("message_dispatch: warning: no handler "
-				 "registed for msg_type %d in pid %u\n",
-				 msg_type, (unsigned int)sys_getpid()));
-		}
+	for (i=0; i<msg_array->num_messages; i++) {
+		messaging_dispatch_rec(msg_ctx, &msg_array->messages[i]);
 	}
-	SAFE_FREE(msgs_buf);
+
+	TALLOC_FREE(msg_array);
 }
 
 /****************************************************************************
@@ -461,60 +490,12 @@ void message_dispatch(void)
  messages on an *odd* byte boundary.
 ****************************************************************************/
 
-static void message_register(int msg_type, 
-			     void (*fn)(int msg_type, struct server_id pid,
-					void *buf, size_t len,
-					void *private_data),
-			     void *private_data)
-{
-	struct dispatch_fns *dfn;
-
-	for (dfn = dispatch_fns; dfn; dfn = dfn->next) {
-		if (dfn->msg_type == msg_type) {
-			dfn->fn = fn;
-			return;
-		}
-	}
-
-	if (!(dfn = SMB_MALLOC_P(struct dispatch_fns))) {
-		DEBUG(0,("message_register: Not enough memory. malloc "
-			 "failed!\n"));
-		return;
-	}
-
-	ZERO_STRUCTPN(dfn);
-
-	dfn->msg_type = msg_type;
-	dfn->fn = fn;
-	dfn->private_data = private_data;
-
-	DLIST_ADD(dispatch_fns, dfn);
-}
-
-/****************************************************************************
- De-register the function for a particular message type.
-****************************************************************************/
-
-static void message_deregister(int msg_type)
-{
-	struct dispatch_fns *dfn, *next;
-
-	for (dfn = dispatch_fns; dfn; dfn = next) {
-		next = dfn->next;
-		if (dfn->msg_type == msg_type) {
-			DLIST_REMOVE(dispatch_fns, dfn);
-			SAFE_FREE(dfn);
-			return;
-		}
-	}	
-}
-
 struct msg_all {
+	struct messaging_context *msg_ctx;
 	int msg_type;
 	uint32 msg_flag;
 	const void *buf;
 	size_t len;
-	BOOL duplicates;
 	int n_sent;
 };
 
@@ -522,41 +503,44 @@ struct msg_all {
  Send one of the messages for the broadcast.
 ****************************************************************************/
 
-static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf,
-		       void *state)
+static int traverse_fn(TDB_CONTEXT *the_tdb,
+		       const struct connections_key *ckey,
+		       const struct connections_data *crec,
+		       void *private_data)
 {
-	struct connections_data crec;
-	struct msg_all *msg_all = (struct msg_all *)state;
+	struct msg_all *msg_all = (struct msg_all *)private_data;
 	NTSTATUS status;
 
-	if (dbuf.dsize != sizeof(crec))
-		return 0;
-
-	memcpy(&crec, dbuf.dptr, sizeof(crec));
-
-	if (crec.cnum != -1)
+	if (crec->cnum != -1)
 		return 0;
 
 	/* Don't send if the receiver hasn't registered an interest. */
 
-	if(!(crec.bcast_msg_flags & msg_all->msg_flag))
+	if(!(crec->bcast_msg_flags & msg_all->msg_flag))
 		return 0;
 
 	/* If the msg send fails because the pid was not found (i.e. smbd died), 
 	 * the msg has already been deleted from the messages.tdb.*/
 
-	status = message_send_pid(crec.pid, msg_all->msg_type,
-				  msg_all->buf, msg_all->len);
+	status = messaging_send_buf(msg_all->msg_ctx,
+				    crec->pid, msg_all->msg_type,
+				    (uint8 *)msg_all->buf, msg_all->len);
 
 	if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
+
+		TDB_DATA key;
 		
 		/* If the pid was not found delete the entry from
 		 * connections.tdb */
 
 		DEBUG(2,("pid %s doesn't exist - deleting connections "
-			 "%d [%s]\n", procid_str_static(&crec.pid), crec.cnum,
-			 crec.servicename));
-		tdb_delete(the_tdb, kbuf);
+			 "%d [%s]\n", procid_str_static(&crec->pid),
+			 crec->cnum, crec->servicename));
+
+		key.dptr = (uint8 *)ckey;
+		key.dsize = sizeof(*ckey);
+
+		tdb_delete(the_tdb, key);
 	}
 	msg_all->n_sent++;
 	return 0;
@@ -577,7 +561,6 @@ static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf,
 BOOL message_send_all(struct messaging_context *msg_ctx,
 		      int msg_type,
 		      const void *buf, size_t len,
-		      BOOL duplicates_allowed,
 		      int *n_sent)
 {
 	struct msg_all msg_all;
@@ -598,10 +581,10 @@ BOOL message_send_all(struct messaging_context *msg_ctx,
 
 	msg_all.buf = buf;
 	msg_all.len = len;
-	msg_all.duplicates = duplicates_allowed;
 	msg_all.n_sent = 0;
+	msg_all.msg_ctx = msg_ctx;
 
-	connections_traverse(traverse_fn, &msg_all);
+	connections_forall(traverse_fn, &msg_all);
 	if (n_sent)
 		*n_sent = msg_all.n_sent;
 	return True;
@@ -622,40 +605,6 @@ void message_unblock(void)
 	BlockSignals(False, SIGUSR1);
 }
 
-/*
- * Samba4 API wrapper around the Samba3 implementation. Yes, I know, we could
- * import the whole Samba4 thing, but I want notify.c from Samba4 in first.
- */
-
-struct messaging_callback {
-	struct messaging_callback *prev, *next;
-	uint32 msg_type;
-	void (*fn)(struct messaging_context *msg, void *private_data, 
-		   uint32_t msg_type, 
-		   struct server_id server_id, DATA_BLOB *data);
-	void *private_data;
-};
-
-struct messaging_context {
-	struct server_id id;
-	struct event_context *event_ctx;
-	struct messaging_callback *callbacks;
-};
-
-static int messaging_context_destructor(struct messaging_context *ctx)
-{
-	struct messaging_callback *cb;
-
-	for (cb = ctx->callbacks; cb; cb = cb->next) {
-		/*
-		 * We unconditionally remove all instances of our callback
-		 * from the tdb basis.
-		 */
-		message_deregister(cb->msg_type);
-	}
-	return 0;
-}
-
 struct event_context *messaging_event_context(struct messaging_context *msg_ctx)
 {
 	return msg_ctx->event_ctx;
@@ -673,7 +622,6 @@ struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
 
 	ctx->id = server_id;
 	ctx->event_ctx = ev;
-	talloc_set_destructor(ctx, messaging_context_destructor);
 
 	if (!message_init(ctx)) {
 		DEBUG(0, ("message_init failed: %s\n", strerror(errno)));
@@ -683,35 +631,12 @@ struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
 	return ctx;
 }
 
-static void messaging_callback(int msg_type, struct server_id pid,
-			       void *buf, size_t len, void *private_data)
-{
-	struct messaging_context *ctx =	talloc_get_type_abort(
-		private_data, struct messaging_context);
-	struct messaging_callback *cb, *next;
-
-	for (cb = ctx->callbacks; cb; cb = next) {
-		/*
-		 * Allow a callback to remove itself
-		 */
-		next = cb->next;
-
-		if (msg_type == cb->msg_type) {
-			DATA_BLOB blob;
-
-			blob.data = (uint8 *)buf;
-			blob.length = len;
-
-			cb->fn(ctx, cb->private_data, msg_type, pid, &blob);
-		}
-	}
-}
-
 /*
  * Register a dispatch function for a particular message type. Allow multiple
  * registrants
 */
-NTSTATUS messaging_register(struct messaging_context *ctx, void *private_data,
+NTSTATUS messaging_register(struct messaging_context *msg_ctx,
+			    void *private_data,
 			    uint32_t msg_type,
 			    void (*fn)(struct messaging_context *msg,
 				       void *private_data, 
@@ -721,7 +646,19 @@ NTSTATUS messaging_register(struct messaging_context *ctx, void *private_data,
 {
 	struct messaging_callback *cb;
 
-	if (!(cb = talloc(ctx, struct messaging_callback))) {
+	/*
+	 * Only one callback per type
+	 */
+
+	for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
+		if (cb->msg_type == msg_type) {
+			cb->fn = fn;
+			cb->private_data = private_data;
+			return NT_STATUS_OK;
+		}
+	}
+
+	if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
 		return NT_STATUS_NO_MEMORY;
 	}
 
@@ -729,8 +666,7 @@ NTSTATUS messaging_register(struct messaging_context *ctx, void *private_data,
 	cb->fn = fn;
 	cb->private_data = private_data;
 
-	DLIST_ADD(ctx->callbacks, cb);
-	message_register(msg_type, messaging_callback, ctx);
+	DLIST_ADD(msg_ctx->callbacks, cb);
 	return NT_STATUS_OK;
 }
 
@@ -759,7 +695,8 @@ NTSTATUS messaging_send(struct messaging_context *msg_ctx,
 			struct server_id server, 
 			uint32_t msg_type, const DATA_BLOB *data)
 {
-	return message_send_pid(server, msg_type, data->data, data->length);
+	return messaging_tdb_send(msg_ctx->tdb, server, msg_type,
+				  data->data, data->length);
 }
 
 NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,