bzr commit into mysql-5.0-bugteam branch (luis.soares:2746) Bug#28796

[Luis Soares]

#At file:///stuff/workspace/mysql-server/bugfix/28796/5.0-bugteam/

 2746 Luis Soares	2008-12-20
      BUG#28796: CHANGE MASTER TO MASTER_HOST="" leads to invalid master.info
      
      This patch addresses the bug reported by checking wether 
      host argument is an empty string or not. If empty, an error is
      reported to the client, otherwise continue normally.
      
      This commit is based on the originally proposed patch and adds 
      a test case as requested during review.
added:
  mysql-test/r/rpl_empty_master_host.result
  mysql-test/t/rpl_empty_master_host.test
modified:
  sql/sql_repl.cc

=== added file 'mysql-test/r/rpl_empty_master_host.result'
--- a/mysql-test/r/rpl_empty_master_host.result	1970-01-01 00:00:00 +0000
+++ b/mysql-test/r/rpl_empty_master_host.result	2008-12-20 03:16:54 +0000
@@ -0,0 +1,24 @@
+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+STOP SLAVE;
+SHOW SLAVE STATUS;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+X	127.0.0.1	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X
+CHANGE MASTER TO MASTER_HOST="";
+ERROR HY000: Incorrect arguments to MASTER_HOST
+SHOW SLAVE STATUS;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+X	127.0.0.1	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X
+CHANGE MASTER TO MASTER_HOST="foo";
+SHOW SLAVE STATUS;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+X	foo	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X
+CHANGE MASTER TO MASTER_HOST="127.0.0.1";
+SHOW SLAVE STATUS;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+X	127.0.0.1	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X	X
+START SLAVE;

=== added file 'mysql-test/t/rpl_empty_master_host.test'
--- a/mysql-test/t/rpl_empty_master_host.test	1970-01-01 00:00:00 +0000
+++ b/mysql-test/t/rpl_empty_master_host.test	2008-12-20 03:16:54 +0000
@@ -0,0 +1,38 @@
+# tests error when setting empty master host 
+# Details in BUG#28796
+
+--source include/master-slave.inc
+
+connection slave;
+STOP SLAVE;
+--source include/wait_for_slave_to_stop.inc
+
+replace_column 1 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 X 13 X 14 X 15 X 16 X 17 X 18
X 19 X 20 X 21 X 22 X 23 X 24 X 25 X 26 X 27 X 28 X 29 X 30 X 31 X 32 X 33 X; 
+SHOW SLAVE STATUS;
+
+# attempt to change to an empty master host should 
+# result in error 1210: "Incorrect arguments to ..."
+
+--error 1210 
+CHANGE MASTER TO MASTER_HOST="";
+
+# show slave status still holds previous information
+replace_column 1 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 X 13 X 14 X 15 X 16 X 17 X 18
X 19 X 20 X 21 X 22 X 23 X 24 X 25 X 26 X 27 X 28 X 29 X 30 X 31 X 32 X 33 X; 
+SHOW SLAVE STATUS;
+
+# changing master to other than empty master host succeeds
+CHANGE MASTER TO MASTER_HOST="foo";
+
+# show slave status should hold "foo" as master host
+replace_column 1 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 X 13 X 14 X 15 X 16 X 17 X 18
X 19 X 20 X 21 X 22 X 23 X 24 X 25 X 26 X 27 X 28 X 29 X 30 X 31 X 32 X 33 X; 
+SHOW SLAVE STATUS;
+
+# changing back to localhost
+CHANGE MASTER TO MASTER_HOST="127.0.0.1";
+
+replace_column 1 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 X 13 X 14 X 15 X 16 X 17 X 18
X 19 X 20 X 21 X 22 X 23 X 24 X 25 X 26 X 27 X 28 X 29 X 30 X 31 X 32 X 33 X; 
+SHOW SLAVE STATUS;
+
+# start slave must succeed.
+START SLAVE;
+--source include/wait_for_slave_to_start.inc

=== modified file 'sql/sql_repl.cc'
--- a/sql/sql_repl.cc	2008-01-31 06:19:29 +0000
+++ b/sql/sql_repl.cc	2008-12-20 03:16:54 +0000
@@ -1080,6 +1080,15 @@ bool change_master(THD* thd, MASTER_INFO
 
   thd->proc_info = "Changing master";
   LEX_MASTER_INFO* lex_mi= &thd->lex->mi;
+
+  /* checks whether host argument is an empty string or not. */
+  if(lex_mi->host && strcmp(lex_mi->host, "") == 0) 
+  {
+    my_error(ER_WRONG_ARGUMENTS, MYF(0), "MASTER_HOST");
+    unlock_slave_threads(mi);
+    DBUG_RETURN(TRUE);
+  }
+
   // TODO: see if needs re-write
   if (init_master_info(mi, master_info_file, relay_log_info_file, 0,
 		       thread_mask))