A fix and test case for Bug#5315 "mysql_change_user() doesn't free

prepared statements."


include/hash.h:
  New declaration for hash_reset() function. The old version was not used.
libmysql/client_settings.h:
  Declaration for mysql_detach_stmt_list().
libmysql/libmysql.c:
  Fix for bug#5315 "mysql_change_user() doesn't free prepared statements":
  add call to mysql_detach_stmt_list(prepared statements) to
  mysql_change_user(): all statements are freed by server, so client
  counterparts need to be marked as not usable.
mysys/hash.c:
  Fix for bug#5315 "mysql_change_user() doesn't free prepared statements":
  implementation of hash_reset(), which frees all hash elements
  and prepares the hash for reuse.
sql-common/client.c:
  Fix for bug#5315 "mysql_change_user() doesn't free prepared statements":
  implementation of mysql_detach_stmt_list(): zero connection pointer
  in given statement list, thus marking given statements as not usable.
sql/sql_class.cc:
  Fix for bug#5315 "mysql_change_user() doesn't free prepared statements":
  reset prepared statements map in THD::change_user().
sql/sql_class.h:
  Fix for bug#5315 "mysql_change_user() doesn't free prepared statements":
  implementation of Statement_map::reset().
  A little cleanup of ~Statement_map(): first empty names_hash, as st_hash
  has a free function, which will delete statements.
tests/client_test.c:
  A test case for bug #5315 "mysql_change_user() doesn't free prepared
  statements".

1 files changed, 26 insertions, 0 deletions

diff --git a/mysys/hash.c b/mysys/hash.c
index ce25ae89b63..6f2788ddce7 100644
--- a/mysys/hash.c
+++ b/mysys/hash.c
@@ -88,6 +88,32 @@ void hash_free(HASH *hash)
   DBUG_VOID_RETURN;
 }
 
+
+/*
+  Delete all elements from the hash (the hash itself is to be reused).
+
+  SYNOPSIS
+    hash_reset()
+      hash   the hash to delete elements of
+*/
+
+void hash_reset(HASH *hash)
+{
+  DBUG_ENTER("hash_reset");
+  if (hash->free)
+  {
+    HASH_LINK *link= dynamic_element(&hash->array, 0, HASH_LINK*);
+    HASH_LINK *end= link + hash->records;
+    for (; link < end; ++link)
+      (*hash->free)(link->data);
+  }
+  reset_dynamic(&hash->array);
+  hash->records= 0;
+  hash->blength= 1;
+  hash->current_record= NO_RECORD;
+  DBUG_VOID_RETURN;
+}
+
 	/* some helper functions */
 
 /*