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.

1 files changed, 3 insertions, 0 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index c930eb0824a..0fdc0b1690c 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -1138,12 +1138,15 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
 
     /* Ensure we don't free security_ctx->user in case we have to revert */
     thd->security_ctx->user= 0;
+    thd->user_connect= 0;
 
     if (acl_authenticate(thd, 0, packet_length))
     {
       /* Free user if allocated by acl_authenticate */
       x_free(thd->security_ctx->user);
       *thd->security_ctx= save_security_ctx;
+      if (thd->user_connect)
+	decrease_user_connections(thd->user_connect);
       thd->user_connect= save_user_connect;
       thd->reset_db(save_db, save_db_length);
       thd->variables.character_set_client= save_character_set_client;