From 8ce93bbd64a38514de82e73fade36ba703ada5dd Mon Sep 17 00:00:00 2001
From: Michael Widenius <monty@askmonty.org>
Date: Tue, 16 Aug 2011 12:32:06 +0300
Subject: Fixed bug that MAX_USER_CONNECTIONS was not working properly in all
 situations (which could cause aborted connects) thd->user_connect is now
 handled in thd->clenup() which will ensure that it works in all context
 (including slaves). I added also some DBUG_ASSERT() to ensure that things are
 working correctly.

sql/sql_acl.cc:
  Reset thd->user_connect on failed check_for_max_user_connections() to ensure we don't decrement value twice.
  Removed not needed call to decrease_user_connections() as thd->cleanup() will now do it.
sql/sql_class.cc:
  Call decrease_user_connections() in thd->cleanup()
sql/sql_connect.cc:
  Ensure we don't allocate thd->user_connect twice.
  Simplify check_for_max_user_connections().
sql/sql_parse.cc:
  Ensure that thd->user_connect is handled properly in for 'change_user' command.
---
 sql/sql_connect.cc | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

(limited to 'sql/sql_connect.cc')

diff --git a/sql/sql_connect.cc b/sql/sql_connect.cc
index def0c8dd951..be53c60e8ca 100644
--- a/sql/sql_connect.cc
+++ b/sql/sql_connect.cc
@@ -49,6 +49,7 @@ int get_or_create_user_conn(THD *thd, const char *user,
 
   DBUG_ASSERT(user != 0);
   DBUG_ASSERT(host != 0);
+  DBUG_ASSERT(thd->user_connect == 0);
 
   user_len= strlen(user);
   temp_len= (strmov(strmov(temp_user, user)+1, host) - temp_user)+1;
@@ -108,7 +109,7 @@ end:
 
 int check_for_max_user_connections(THD *thd, USER_CONN *uc)
 {
-  int error=0;
+  int error= 1;
   DBUG_ENTER("check_for_max_user_connections");
 
   (void) pthread_mutex_lock(&LOCK_user_conn);
@@ -116,7 +117,6 @@ int check_for_max_user_connections(THD *thd, USER_CONN *uc)
       max_user_connections < (uint) uc->connections)
   {
     my_error(ER_TOO_MANY_USER_CONNECTIONS, MYF(0), uc->user);
-    error=1;
     goto end;
   }
   time_out_user_resource_limits(thd, uc);
@@ -126,7 +126,6 @@ int check_for_max_user_connections(THD *thd, USER_CONN *uc)
     my_error(ER_USER_LIMIT_REACHED, MYF(0), uc->user,
              "max_user_connections",
              (long) uc->user_resources.user_conn);
-    error= 1;
     goto end;
   }
   if (uc->user_resources.conn_per_hour &&
@@ -135,10 +134,10 @@ int check_for_max_user_connections(THD *thd, USER_CONN *uc)
     my_error(ER_USER_LIMIT_REACHED, MYF(0), uc->user,
              "max_connections_per_hour",
              (long) uc->user_resources.conn_per_hour);
-    error=1;
     goto end;
   }
   uc->conn_per_hour++;
+  error= 0;
 
 end:
   if (error)
@@ -1027,8 +1026,17 @@ void end_connection(THD *thd)
 {
   NET *net= &thd->net;
   plugin_thdvar_cleanup(thd);
+
   if (thd->user_connect)
+  {
+    /*
+      We decrease this variable early to make it easy to log again quickly.
+      This code is not critical as we will in any case do this test
+      again in thd->cleanup()
+    */
     decrease_user_connections(thd->user_connect);
+    thd->user_connect= 0;
+  }
 
   if (thd->killed || (net->error && net->vio != 0))
   {
-- 
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