Bug #15775 "drop user" command does not refresh acl_check_hosts

 - Update patch for 5.0 
 - Added common function to be called when 'acl_users' has been modified


mysql-test/r/grant2.result:
  Use "create user" to avoid warnings about missing fields
mysql-test/t/grant2.test:
  Use "create user" to avoid warnings about missing fields
sql/sql_acl.cc:
  Add new function "rebuild_check_host" that is to be called when the 'acl_users'
  list has changed.
  Call function "rebuild_check_host" from mysql_drop_user, mysql_rename_user and acl_insert_user.
  Use "acl_user->host.hostname" as key when searching the acl_check_hosts in init_check_host.

mysql-test/r/grant2.result

@@ -107,14 +107,13 @@ delete from mysql.columns_priv where user like 'mysqltest\_%';
 flush privileges;
 drop database mysqltest;
 use test;
-insert into mysql.user (user, host) values
-('mysqltest_1', 'host1'),
-('mysqltest_2', 'host2'),
-('mysqltest_3', 'host3'),
-('mysqltest_4', 'host4'),
-('mysqltest_5', 'host5'),
-('mysqltest_6', 'host6'),
-('mysqltest_7', 'host7');
+create user mysqltest_1@host1;
+create user mysqltest_2@host2;
+create user mysqltest_3@host3;
+create user mysqltest_4@host4;
+create user mysqltest_5@host5;
+create user mysqltest_6@host6;
+create user mysqltest_7@host7;
 flush privileges;
 drop user mysqltest_3@host3;
 drop user mysqltest_1@host1, mysqltest_2@host2, mysqltest_4@host4,

mysql-test/t/grant2.test

@@ -161,14 +161,13 @@ use test;
 #
 
 # Create some test users
-insert into mysql.user (user, host) values
-	('mysqltest_1', 'host1'),
-	('mysqltest_2', 'host2'),
-	('mysqltest_3', 'host3'),
-	('mysqltest_4', 'host4'),
-	('mysqltest_5', 'host5'),
-	('mysqltest_6', 'host6'),
-	('mysqltest_7', 'host7');
+create user mysqltest_1@host1;
+create user mysqltest_2@host2;
+create user mysqltest_3@host3;
+create user mysqltest_4@host4;
+create user mysqltest_5@host5;
+create user mysqltest_6@host6;
+create user mysqltest_7@host7;
 flush privileges;
 
 # Drop one user

sql/sql_acl.cc

@@ -68,6 +68,7 @@ static ulong get_access(TABLE *form,uint fieldnr, uint *next_field=0);
 static int acl_compare(ACL_ACCESS *a,ACL_ACCESS *b);
 static ulong get_sort(uint count,...);
 static void init_check_host(void);
+static void rebuild_check_host(void);
 static ACL_USER *find_acl_user(const char *host, const char *user,
                                my_bool exact);
 static bool update_user_table(THD *thd, TABLE *table,
@@ -1095,10 +1096,8 @@ static void acl_insert_user(const char *user, const char *host,
   qsort((gptr) dynamic_element(&acl_users,0,ACL_USER*),acl_users.elements,
 	sizeof(ACL_USER),(qsort_cmp) acl_compare);
 
-  /* We must free acl_check_hosts as its memory is mapped to acl_user */
-  delete_dynamic(&acl_wild_hosts);
-  hash_free(&acl_check_hosts);
-  init_check_host();
+  /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
+  rebuild_check_host();
 }
 
 
@@ -1283,7 +1282,7 @@ static void init_check_host(void)
 	if (j == acl_wild_hosts.elements)	// If new
 	  (void) push_dynamic(&acl_wild_hosts,(char*) &acl_user->host);
       }
-      else if (!hash_search(&acl_check_hosts,(byte*) &acl_user->host,
+      else if (!hash_search(&acl_check_hosts,(byte*) acl_user->host.hostname,
 			    (uint) strlen(acl_user->host.hostname)))
       {
 	if (my_hash_insert(&acl_check_hosts,(byte*) acl_user))
@@ -1300,6 +1299,22 @@ static void init_check_host(void)
 }
 
 
+/*
+  Rebuild lists used for checking of allowed hosts
+
+  We need to rebuild 'acl_check_hosts' and 'acl_wild_hosts' after adding,
+  dropping or renaming user, since they contain pointers to elements of
+  'acl_user' array, which are invalidated by drop operation, and use
+  ACL_USER::host::hostname as a key, which is changed by rename.
+*/
+void rebuild_check_host(void)
+{
+  delete_dynamic(&acl_wild_hosts);
+  hash_free(&acl_check_hosts);
+  init_check_host();
+}
+
+
 /* Return true if there is no users that can match the given host */
 
 bool acl_check_host(const char *host, const char *ip)
@@ -5241,6 +5256,9 @@ bool mysql_drop_user(THD *thd, List <LEX_USER> &list)
     }
   }
 
+  /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
+  rebuild_check_host();
+
   VOID(pthread_mutex_unlock(&acl_cache->lock));
   rw_unlock(&LOCK_grant);
   close_thread_tables(thd);
@@ -5265,7 +5283,7 @@ bool mysql_drop_user(THD *thd, List <LEX_USER> &list)
 
 bool mysql_rename_user(THD *thd, List <LEX_USER> &list)
 {
-  int result= 0;
+  int result;
   String wrong_users;
   LEX_USER *user_from;
   LEX_USER *user_to;
@@ -5297,6 +5315,9 @@ bool mysql_rename_user(THD *thd, List <LEX_USER> &list)
     }
   }
 
+  /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
+  rebuild_check_host();
+
   VOID(pthread_mutex_unlock(&acl_cache->lock));
   rw_unlock(&LOCK_grant);
   close_thread_tables(thd);