Add new table called emulab_locks, which is a table of name,value

pairs. Used only by the pool daemon, to control concurrency between
the pool daemon and mapper.

db/dbboot.in

@@ -2,7 +2,7 @@
 
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2000-2002, 2004 University of Utah and the Flux Group.
+# Copyright (c) 2000-2010 University of Utah and the Flux Group.
 # All rights reserved.
 #
 use English;
@@ -69,6 +69,11 @@ DBQueryFatal("update experiments set event_sched_pid=0");
 #
 DBQueryFatal("delete from login");
 
+#
+# Clear the pool daemon lock.
+#
+DBQueryFatal("replace into emulab_locks set name='pool_daemon',value='0'");
+
 #
 # Check for experiments stuck in transition.
 #

sql/database-create.sql

@@ -463,6 +463,17 @@ CREATE TABLE `emulab_indicies` (
   PRIMARY KEY  (`name`)
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1;
 
+--
+-- Table structure for table `emulab_locks`
+--
+
+DROP TABLE IF EXISTS `emulab_locks`;
+CREATE TABLE `emulab_locks` (
+  `name` varchar(64) NOT NULL default '',
+  `value` int(10) unsigned NOT NULL default '0',
+  PRIMARY KEY  (`name`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1;
+
 --
 -- Table structure for table `emulab_pubs`
 --

sql/database-fill-supplemental.sql

@@ -20,3 +20,4 @@ INSERT IGNORE INTO os_boot_cmd VALUES ('Linux','9.0','linkdelay','linkdelay');
 
 INSERT IGNORE INTO emulab_indicies (name,idx) VALUES ('cur_log_seq', 1);
 INSERT IGNORE INTO emulab_indicies (name,idx) VALUES ('next_osid', 10000);
+INSERT IGNORE INTO emulab_locks (name,value) VALUES ('pool_daemon', 0);

sql/updates/4/213

+#
+# Add a locks table, for the pool_daemon.
+#
+use strict;
+use libdb;
+
+sub DoUpdate($$$)
+{
+    if (!DBTableExists("emulab_locks")) {
+	DBQueryFatal("CREATE TABLE `emulab_locks` ( ".
+		     " `name` varchar(64) NOT NULL default '', ".
+		     " `value` int(10) unsigned NOT NULL default '0', ".
+		     " PRIMARY KEY  (`name`) ".
+		     ") ENGINE=MyISAM DEFAULT CHARSET=latin1");
+    }
+    DBQueryFatal("lock tables emulab_locks write");
+    my $query_result =
+	DBQueryFatal("select * from emulab_locks where name='pool_daemon'");
+    if (!$query_result->numrows) {
+	DBQueryFatal("insert into emulab_locks values ('pool_daemon', 0)");
+    }
+    DBQueryFatal("unlock tables");
+    return 0;
+}
+1;