Add 3 second timeout when terminating server and sending print notify

messages. Stops build-up of large numbers of smbd's waiting to terminate
on large print throughput.
Jeremy.
(This used to be commit 07efebb984)

source3/lib/messages.c

@@ -160,8 +160,8 @@ static BOOL message_notify(pid_t pid)
  Send a message to a particular pid.
 ****************************************************************************/
 
-BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
+static BOOL message_send_pid_internal(pid_t pid, int msg_type, const void *buf, size_t len,
-		      BOOL duplicates_allowed)
+		      BOOL duplicates_allowed, unsigned int timeout)
 {
 	TDB_DATA kbuf;
 	TDB_DATA dbuf;
@@ -200,7 +200,17 @@ BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
 		/* If duplicates are allowed we can just append the message and return. */
 
 		/* lock the record for the destination */
-		tdb_chainlock(tdb, kbuf);
+		if (timeout) {
+			if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+				DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
+				return False;
+			}
+		} else {
+			if (tdb_chainlock(tdb, kbuf) == -1) {
+				DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
+				return False;
+			}
+		}	
 		tdb_append(tdb, kbuf, dbuf);
 		tdb_chainunlock(tdb, kbuf);
 
@@ -210,7 +220,18 @@ BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
 	}
 
 	/* lock the record for the destination */
-	tdb_chainlock(tdb, kbuf);
+	if (timeout) {
+		if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+			DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
+			return False;
+		}
+	} else {
+		if (tdb_chainlock(tdb, kbuf) == -1) {
+			DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
+			return False;
+		}
+	}	
+
 	old_dbuf = tdb_fetch(tdb, kbuf);
 
 	if (!old_dbuf.dptr) {
@@ -236,7 +257,7 @@ BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
 		if (!memcmp(ptr, &rec, sizeof(rec))) {
 			if (!len || (len && !memcmp( ptr + sizeof(rec), buf, len))) {
 				tdb_chainunlock(tdb, kbuf);
-				DEBUG(10,("message_send_pid: discarding duplicate message.\n"));
+				DEBUG(10,("message_send_pid_internal: discarding duplicate message.\n"));
 				SAFE_FREE(dbuf.dptr);
 				SAFE_FREE(old_dbuf.dptr);
 				return True;
@@ -258,6 +279,25 @@ BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
 	return message_notify(pid);
 }
 
+/****************************************************************************
+ Send a message to a particular pid - no timeout.
+****************************************************************************/
+
+BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len, BOOL duplicates_allowed)
+{
+	return message_send_pid_internal(pid, msg_type, buf, len, duplicates_allowed, 0);
+}
+
+/****************************************************************************
+ Send a message to a particular pid, with timeout in seconds.
+****************************************************************************/
+
+BOOL message_send_pid_with_timeout(pid_t pid, int msg_type, const void *buf, size_t len,
+		BOOL duplicates_allowed, unsigned int timeout)
+{
+	return message_send_pid_internal(pid, msg_type, buf, len, duplicates_allowed, timeout);
+}
+
 /****************************************************************************
  Retrieve all messages for the current process.
 ****************************************************************************/

source3/printing/notify.c

@@ -56,7 +56,7 @@ BOOL print_notify_messages_pending(void)
  Send the batched messages - on a per-printer basis.
 *******************************************************************/
 
-static void print_notify_send_messages_to_printer(const char *printer)
+static void print_notify_send_messages_to_printer(const char *printer, unsigned int timeout)
 {
 	char *buf;
 	struct notify_queue *pq, *pq_next;
@@ -109,14 +109,14 @@ static void print_notify_send_messages_to_printer(const char *printer)
 		return;
 
 	for (i = 0; i < num_pids; i++)
-		message_send_pid(pid_list[i], MSG_PRINTER_NOTIFY2, buf, offset, True);
+		message_send_pid_with_timeout(pid_list[i], MSG_PRINTER_NOTIFY2, buf, offset, True, timeout);
 }
 
 /*******************************************************************
  Actually send the batched messages.
 *******************************************************************/
 
-void print_notify_send_messages(void)
+void print_notify_send_messages(unsigned int timeout)
 {
 	if (!print_notify_messages_pending())
 		return;
@@ -125,7 +125,7 @@ void print_notify_send_messages(void)
 		return;
 
 	while (print_notify_messages_pending())
-		print_notify_send_messages_to_printer(notify_queue_head->printername);
+		print_notify_send_messages_to_printer(notify_queue_head->printername, timeout);
 
 	talloc_destroy_pool(send_ctx);
 }

source3/smbd/process.c

@@ -1228,7 +1228,7 @@ machine %s in domain %s.\n", global_myname(), lp_workgroup() ));
 
   /* Send any queued printer notify message to interested smbd's. */
 
-  print_notify_send_messages();
+  print_notify_send_messages(0);
 
   /*
    * Modify the select timeout depending upon

source3/smbd/server.c

@@ -550,7 +550,7 @@ void exit_server(const char *reason)
 
 	invalidate_all_vuids();
 
-	print_notify_send_messages();	
+	print_notify_send_messages(3); /* 3 second timeout. */
 
 	/* delete our entry in the connections database. */
 	yield_connection(NULL,"");

source3/tdb/tdbutil.c

@@ -51,7 +51,7 @@ static TDB_DATA make_tdb_data(const char *dptr, size_t dsize)
  Lock a chain with timeout (in seconds).
 ****************************************************************************/
 
-static int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
+static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
 {
 	/* Allow tdb_chainlock to be interrupted by an alarm. */
 	int ret;
@@ -72,7 +72,7 @@ static int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned
 		alarm(0);
 		CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
 		if (gotalarm) {
-			DEBUG(0,("tdb_chainlock_with_timeout: alarm (%u) timed out for key %s in tdb %s\n",
+			DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
 				timeout, key.dptr, tdb->name ));
 			/* TODO: If we time out waiting for a lock, it might
 			 * be nice to use F_GETLK to get the pid of the
@@ -85,6 +85,15 @@ static int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned
 	return ret;
 }
 
+/****************************************************************************
+ Write lock a chain. Return -1 if timeout or lock failed.
+****************************************************************************/
+
+int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
+{
+	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
+}
+
 /****************************************************************************
  Lock a chain by string. Return -1 if timeout or lock failed.
 ****************************************************************************/
@@ -93,7 +102,7 @@ int tdb_lock_bystring(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout
 {
 	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);
 	
-	return tdb_chainlock_with_timeout(tdb, key, timeout, F_WRLCK);
+	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
 }
 
 /****************************************************************************
@@ -115,7 +124,7 @@ int tdb_read_lock_bystring(TDB_CONTEXT *tdb, const char *keyval, unsigned int ti
 {
 	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);
 	
-	return tdb_chainlock_with_timeout(tdb, key, timeout, F_RDLCK);
+	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
 }
 
 /****************************************************************************

source3/utils/smbcontrol.c

@@ -644,7 +644,7 @@ static BOOL do_command(char *dest, char *msg_name, int iparams, char **params)
 	/* check if we have any pending print notify messages */
 
 	if ( check_notify_msgs )
-		print_notify_send_messages();
+		print_notify_send_messages(0);
 		
 	return (True);
 }