manual merge

charged sql/sql_db.cc only
(
changed length in mysql_create_db to path_len
so as it was calculated in the first unpack_dirname
in my previous fix for Bug #4378
'"create database IF NOT EXISTS thing" returns an error'
)

sql/sql_db.cc

@@ -378,9 +378,9 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
   char	 path[FN_REFLEN+16];
   long result= 1;
   int error= 0;
-  uint length;
   MY_STAT stat_info;
   uint create_options= create_info ? create_info->options : 0;
+  uint path_len;
   DBUG_ENTER("mysql_create_db");
   
   VOID(pthread_mutex_lock(&LOCK_mysql_create_db));
@@ -394,7 +394,8 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
 
   /* Check directory */
   strxmov(path, mysql_data_home, "/", db, NullS);
-  unpack_dirname(path,path);			// Convert if not unix
+  path_len= unpack_dirname(path,path);    // Convert if not unix
+  path[path_len-1]= 0;                    // Remove last '/' from path
 
   if (my_stat(path,&stat_info,MYF(0)))
   {
@@ -413,7 +414,6 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
       my_error(EE_STAT, MYF(0),path,my_errno);
       goto exit;
     }
-    strend(path)[-1]=0;				// Remove last '/' from path
     if (my_mkdir(path,0777,MYF(0)) < 0)
     {
       my_error(ER_CANT_CREATE_DB,MYF(0),db,my_errno);
@@ -422,15 +422,15 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
     }
   }
 
-  length= unpack_dirname(path, path);
-  strmov(path+ length, MY_DB_OPT_FILE);
+  path[path_len-1]= FN_LIBCHAR;
+  strmake(path+path_len, MY_DB_OPT_FILE, sizeof(path)-path_len-1);
   if (write_db_opt(thd, path, create_info))
   {
     /*
       Could not create options file.
       Restore things to beginning.
     */
-    path[length]= 0;
+    path[path_len]= 0;
     if (rmdir(path) >= 0)
     {
       error= -1;