5.1 version of fix for:

  Bug #23667 "CREATE TABLE LIKE is not isolated from alteration
              by other connections"
  Bug #18950 "CREATE TABLE LIKE does not obtain LOCK_open"
As well as:
  Bug #25578 "CREATE TABLE LIKE does not require any privileges
              on source table".

The first and the second bugs resulted in various errors and wrong
binary log order when one tried to execute concurrently CREATE TABLE LIKE
statement and DDL statements on source table or DML/DDL statements on its
target table.

The problem was caused by incomplete protection/table-locking against
concurrent statements implemented in mysql_create_like_table() routine.
We solve it by simply implementing such protection in proper way.
Most of actual work for 5.1 was already done by fix for bug 20662 and
preliminary patch changing locking in ALTER TABLE.

The third bug allowed user who didn't have any privileges on table create
its copy and therefore circumvent privilege check for SHOW CREATE TABLE.

This patch solves this problem by adding privilege check, which was missing.

Finally it also removes some duplicated code from mysql_create_like_table()
and thus fixes bug #26869 "TABLE_LIST::table_name_length inconsistent with
TABLE_LIST::table_name".


mysql-test/r/create-big.result:
  Added test coverage for concurrency-related issues with CREATE TABLE LIKE.
mysql-test/r/create.result:
  Adjusted error-code in the test case after refactoring code that
  implements CREATE TABLE ... LIKE.
mysql-test/r/grant2.result:
  Added test for bug#25578 "CREATE TABLE LIKE does not require any privileges
  on source table".
mysql-test/t/create-big.test:
  Added test coverage for concurrency-related issues with CREATE TABLE LIKE.
mysql-test/t/create.test:
  Adjusted error-code in the test case after refactoring code that
  implements CREATE TABLE ... LIKE.
mysql-test/t/disabled.def:
  Recent code changes ensured that CREATE TABLE LIKE statement is properly
  isolated against other statements, so synchronization.test should no
  longer fail (see fix for bug 20662 and preliminary patch for bug 23667
  changing ALTER TABLE locking).
mysql-test/t/grant2.test:
  Added test for bug#25578 "CREATE TABLE LIKE does not require any privileges
  on source table".
sql/handler.h:
  Introduced new flag for HA_CREATE_INFO::options in order to be able to
  distinguish CREATE TABLE ... LIKE from other types of CREATE TABLE.
sql/mysql_priv.h:
  mysql_create_like_table() now takes source table name not as a
  Table_ident object but as regular table list element.
sql/sql_lex.h:
  Removed LEX::like_name member. Now we use special flag in
  LEX::create_info::options for distinguishing CREATE TABLE ... LIKE
  from other types of CREATE TABLE and store name of source table as
  regular element in statement's table list.
sql/sql_parse.cc:
  CREATE TABLE ... LIKE implementation now uses statement's table list
  for storing information about the source table. We also use flag
  in LEX::create_info.options for distinguishing it from other types
  of CREATE TABLE.
  Finally CREATE TABLE ... LIKE now requires the same privileges on
  the source tables as SHOW CREATE TABLE. Moved this privilege check
  to check_show_create_table_access() function.
sql/sql_partition.cc:
  Now we use special flag in LEX::create_info::options for distinguishing
  CREATE TABLE ... LIKE from other types of CREATE TABLE and store name
  of source table as regular element in statement's table list.
sql/sql_table.cc:
  mysql_create_like_table():  
   - Commented and cleaned-up a bit code which is responsible for achieving
     isolation from concurrent statements. Most of actual work was done by
     fix for bug 20662 and preliminary patch changing locking locking in
     ALTER TABLE, so here we do minor things like relaxing locking on
     source table (we don't need lock on it, to have it open is enough) and
     adjusting code to make it more friendly against code implementing I_S.
   - Get rid of duplicated code related to source database/table name
     handling. All these operations are already done in
     st_select_lex::add_table_to_list(), so we achieve the same effect
     by including source table into the statement's table list.
sql/sql_yacc.yy:
  Now we use special flag in LEX::create_info::options for distinguishing
  CREATE TABLE ... LIKE from other types of CREATE TABLE and store name
  of source table as regular element in statement's table list.

1 files changed, 45 insertions, 92 deletions

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 149c746a1de..2727b014db0 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -4665,114 +4665,51 @@ bool mysql_preload_keys(THD* thd, TABLE_LIST* tables)
   SYNOPSIS
     mysql_create_like_table()
     thd		Thread object
-    table	Table list (one table only)
+    table       Table list element for target table
+    src_table   Table list element for source table
     create_info Create info
-    table_ident Src table_ident
 
   RETURN VALUES
     FALSE OK
     TRUE  error
 */
 
-bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
-                             HA_CREATE_INFO *lex_create_info,
-                             Table_ident *table_ident)
+bool mysql_create_like_table(THD* thd, TABLE_LIST* table, TABLE_LIST* src_table,
+                             HA_CREATE_INFO *lex_create_info)
 {
-  TABLE *tmp_table, *name_lock= 0;
+  TABLE *name_lock= 0;
   char src_path[FN_REFLEN], dst_path[FN_REFLEN];
-  char src_table_name_buff[FN_REFLEN], src_db_name_buff[FN_REFLEN];
   uint dst_path_length;
   char *db= table->db;
   char *table_name= table->table_name;
-  char *src_db;
-  char *src_table= table_ident->table.str;
   int  err;
   bool res= TRUE;
-  enum legacy_db_type not_used;
+  uint not_used;
   HA_CREATE_INFO *create_info;
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   char tmp_path[FN_REFLEN];
 #endif
   char ts_name[FN_LEN];
-  TABLE_LIST src_tables_list;
   DBUG_ENTER("mysql_create_like_table");
 
   if (!(create_info= copy_create_info(lex_create_info)))
   {
     DBUG_RETURN(TRUE);
   }
-  DBUG_ASSERT(table_ident->db.str); /* Must be set in the parser */
-  src_db= table_ident->db.str;
+
+  /* CREATE TABLE ... LIKE is not allowed for views. */
+  src_table->required_type= FRMTYPE_TABLE;
 
   /*
-    Validate the source table
+    By opening source table we guarantee that it exists and no concurrent
+    DDL operation will mess with it. Later we also take an exclusive
+    name-lock on target table name, which makes copying of .frm file,
+    call to ha_create_table() and binlogging atomic against concurrent DML
+    and DDL operations on target table. Thus by holding both these "locks"
+    we ensure that our statement is properly isolated from all concurrent
+    operations which matter.
   */
-  if (check_string_char_length(&table_ident->table, "", NAME_CHAR_LEN,
-                               system_charset_info, 1) ||
-      (table_ident->table.length &&
-       check_table_name(src_table,table_ident->table.length)))
-  {
-    my_error(ER_WRONG_TABLE_NAME, MYF(0), src_table);
-    DBUG_RETURN(TRUE);
-  }
-  if (!src_db || check_db_name(&table_ident->db))
-  {
-    my_error(ER_WRONG_DB_NAME, MYF(0), src_db ? src_db : "NULL");
-    DBUG_RETURN(-1);
-  }
-
-  if ((tmp_table= find_temporary_table(thd, src_db, src_table)))
-    strxmov(src_path, tmp_table->s->path.str, reg_ext, NullS);
-  else
-  {
-    build_table_filename(src_path, sizeof(src_path),
-                         src_db, src_table, reg_ext, 0);
-    /* Resolve symlinks (for windows) */
-    unpack_filename(src_path, src_path);
-    if (lower_case_table_names)
-      my_casedn_str(files_charset_info, src_path);
-    if (access(src_path, F_OK))
-    {
-      my_error(ER_BAD_TABLE_ERROR, MYF(0), src_table);
-      goto err;
-    }
-  }
-
-  /* 
-     create like should be not allowed for Views, Triggers, ... 
-  */
-  if (mysql_frm_type(thd, src_path, &not_used) != FRMTYPE_TABLE)
-  {
-    my_error(ER_WRONG_OBJECT, MYF(0), src_db, src_table, "BASE TABLE");
-    goto err;
-  }
-
-  if (lower_case_table_names)
-  {
-    if (src_db)
-    {
-      strmake(src_db_name_buff, src_db,
-              min(sizeof(src_db_name_buff) - 1, table_ident->db.length));
-      my_casedn_str(files_charset_info, src_db_name_buff);
-      src_db= src_db_name_buff;
-    }
-    if (src_table)
-    {
-      strmake(src_table_name_buff, src_table,
-              min(sizeof(src_table_name_buff) - 1, table_ident->table.length));
-      my_casedn_str(files_charset_info, src_table_name_buff);
-      src_table= src_table_name_buff;
-    }
-  }
-
-  bzero((gptr)&src_tables_list, sizeof(src_tables_list));
-  src_tables_list.db= src_db;
-  src_tables_list.db_length= table_ident->db.length;
-  src_tables_list.lock_type= TL_READ;
-  src_tables_list.table_name= src_table;
-  src_tables_list.alias= src_table;
-
-  if (simple_open_n_lock_tables(thd, &src_tables_list))
+  if (open_tables(thd, &src_table, &not_used, 0))
     DBUG_RETURN(TRUE);
 
   /*
@@ -4781,17 +4718,19 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
     Add something to get possible tablespace info from src table,
     it can get valid tablespace name only for disk-base ndb table
   */
-  if ((src_tables_list.table->file->get_tablespace_name(thd, ts_name, FN_LEN)))
+  if ((src_table->table->file->get_tablespace_name(thd, ts_name, FN_LEN)))
   {
     create_info->tablespace= ts_name;
     create_info->storage_media= HA_SM_DISK;
   }
 
-  /*
-    Validate the destination table
+  strxmov(src_path, src_table->table->s->path.str, reg_ext, NullS);
 
-    skip the destination table name checking as this is already
-    validated.
+  DBUG_EXECUTE_IF("sleep_create_like_before_check_if_exists", my_sleep(6000000););
+
+  /*
+    Check that destination tables does not exist. Note that its name
+    was already checked when it was added to the table list.
   */
   if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
   {
@@ -4812,15 +4751,29 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
       goto table_exists;
   }
 
+  DBUG_EXECUTE_IF("sleep_create_like_before_copy", my_sleep(6000000););
+
   /*
     Create a new table by copying from source table
+
+    Altough exclusive name-lock on target table protects us from concurrent
+    DML and DDL operations on it we still want to wrap .FRM creation and call
+    to ha_create_table() in critical section protected by LOCK_open in order
+    to provide minimal atomicity against operations which disregard name-locks,
+    like I_S implementation, for example. This is a temporary and should not
+    be copied. Instead we should fix our code to always honor name-locks.
+
+    Also some engines (e.g. NDB cluster) require that LOCK_open should be held
+    during the call to ha_create_table(). See bug #28614 for more info.
   */
+  VOID(pthread_mutex_lock(&LOCK_open));
   if (my_copy(src_path, dst_path, MYF(MY_DONT_OVERWRITE_FILE)))
   {
     if (my_errno == ENOENT)
       my_error(ER_BAD_DB_ERROR,MYF(0),db);
     else
       my_error(ER_CANT_CREATE_FILE,MYF(0),dst_path,my_errno);
+    VOID(pthread_mutex_unlock(&LOCK_open));
     goto err;
   }
 
@@ -4842,10 +4795,12 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
   strmov(src_path, tmp_path);
   my_copy(src_path, dst_path, MYF(MY_DONT_OVERWRITE_FILE));
 #endif
+
+  DBUG_EXECUTE_IF("sleep_create_like_before_ha_create", my_sleep(6000000););
+
   dst_path[dst_path_length - reg_ext_length]= '\0';  // Remove .frm
-  pthread_mutex_lock(&LOCK_open);  
   err= ha_create_table(thd, dst_path, db, table_name, create_info, 1);
-  pthread_mutex_unlock(&LOCK_open);
+  VOID(pthread_mutex_unlock(&LOCK_open));
   if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
   {
     if (err || !open_temporary_table(thd, dst_path, db, table_name, 1))
@@ -4862,6 +4817,8 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
     goto err;	    /* purecov: inspected */
   }
 
+  DBUG_EXECUTE_IF("sleep_create_like_before_binlogging", my_sleep(6000000););
+
   /*
     We have to write the query before we unlock the tables.
   */
@@ -4881,14 +4838,10 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
            3    temporary    normal Nothing
            4    temporary temporary Nothing
            ==== ========= ========= ==============================
-
-       The variable 'tmp_table' below is used to see if the source
-       table is a temporary table: if it is set, then the source table
-       was a temporary table and we can take apropriate actions.
     */
     if (!(create_info->options & HA_LEX_CREATE_TMP_TABLE))
     {
-      if (tmp_table)                            // Case 2
+      if (src_table->table->s->tmp_table)               // Case 2
       {
         char buf[2048];
         String query(buf, sizeof(buf), system_charset_info);