Fix for a user management system that resources can be reset to zero

with a GRANT statement.

sql/sql_acl.cc

@@ -652,11 +652,11 @@ static void acl_update_user(const char *user, const char *host,
 	  acl_user->host.hostname && !strcmp(host,acl_user->host.hostname))
       {
 	acl_user->access=privileges;
-	if (mqh->questions)
+	if (mqh->bits & 1)
 	  acl_user->user_resource.questions=mqh->questions;
-	if (mqh->updates)
+	if (mqh->bits & 2)
 	  acl_user->user_resource.updates=mqh->updates;
-	if (mqh->connections)
+	if (mqh->bits & 4)
 	  acl_user->user_resource.connections=mqh->connections;
 #ifdef HAVE_OPENSSL  
 	acl_user->ssl_type=ssl_type;
@@ -1300,11 +1300,11 @@ static int replace_user_table(THD *thd, TABLE *table, const LEX_USER &combo,
 #endif /* HAVE_OPENSSL */
 
     USER_RESOURCES mqh = thd->lex.mqh;
-    if (mqh.questions)
+    if (mqh.bits & 1)
       table->field[28]->store((longlong) mqh.questions);
-    if (mqh.updates)
+    if (mqh.bits & 2)
       table->field[29]->store((longlong) mqh.updates);
-    if (mqh.connections)
+    if (mqh.bits & 4)
       table->field[30]->store((longlong) mqh.connections);
     mqh_used = mqh_used || mqh.questions || mqh.updates || mqh.connections;
   }

sql/sql_parse.cc

@@ -392,7 +392,7 @@ static void reset_mqh(THD *thd, LEX_USER *lu, bool get_them=false)
   if (lu)  // for GRANT 
   {
     USER_CONN *uc;
-    volatile uint temp_len=lu->user.length+lu->host.length+2;
+    uint temp_len=lu->user.length+lu->host.length+2;
     char temp_user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];
 
     memcpy(temp_user,lu->user.str,lu->user.length);

sql/sql_yacc.yy

@@ -3669,14 +3669,17 @@ grant_option:
         | MAX_QUERIES_PER_HOUR ULONG_NUM
         {
 	  Lex->mqh.questions=$2;
+	  Lex->mqh.bits |= 1;
 	}
         | MAX_UPDATES_PER_HOUR ULONG_NUM
         {
 	  Lex->mqh.updates=$2;
+	  Lex->mqh.bits |= 2;
 	}
         | MAX_CONNECTIONS_PER_HOUR ULONG_NUM
         {
 	  Lex->mqh.connections=$2;
+	  Lex->mqh.bits |= 4;
 	};
 
 begin:

sql/structs.h

@@ -163,7 +163,7 @@ typedef struct	st_lex_user {
 
 
 typedef struct user_resources {
-  uint questions, updates, connections;
+  uint questions, updates, connections, bits;
 } USER_RESOURCES;
 
 typedef struct  user_conn {