WL#1366: Use the schema (db) associated with an SP.

Phase 3: Made qualified names work for functions as well.


mysql-test/r/sp-security.result:
  New testcases for functions with qualified names.
mysql-test/t/sp-security.test:
  New testcases for functions with qualified names.
sql/item_func.cc:
  Added error handling for stored function, if it doesn't exist.
sql/item_func.h:
  Set null_value if execution of a stored function fails.
sql/mysql_priv.h:
  Reverted previous change: No optional args for mysql_change_db().
  (SPs use a specially tailored function instead.)
sql/sp.cc:
  Copied mysql_change_db() from sql_db.cc and modified specially for SPs.
sql/sp_head.cc:
  Fixed error handling for errors in functions during query/statement execution.
sql/sql_db.cc:
  Reverted previous change: No optional args for mysql_change_db().
  (SPs use a specially tailored function instead.)
sql/sql_yacc.yy:
  Reworked the stored function/UDF invokation parsing and added qualified names
  for stored functions. UDFs now have precedence over stored functions (whith
  unqualified name). When using an unqualified name, only IDENT_sys is allowed
  (i.e. no unreserved keywords), since we get unresolvable reduce/reduce conflicts
  otherwise.

sql/sp.cc

@@ -16,6 +16,7 @@
 
 
 #include "mysql_priv.h"
+#include "sql_acl.h"
 #include "sp.h"
 #include "sp_head.h"
 #include "sp_cache.h"
@@ -960,19 +961,104 @@ sp_use_new_db(THD *thd, char *newdb, char *olddb, uint olddblen,
   }
 }
 
+/*
+  Change database.
+
+  SYNOPSIS
+    sp_change_db()
+    thd		    Thread handler
+    name	    Database name
+    empty_is_ok     True= it's ok with "" as name
+    no_access_check True= don't do access check
+
+  DESCRIPTION
+    This is the same as mysql_change_db(), but with some extra
+    arguments for Stored Procedure usage; doing implicit "use" 
+    when executing an SP in a different database.
+    We also use different error routines, since this might be
+    invoked from a function when executing a query or statement.
+    Note: We would have prefered to reuse mysql_change_db(), but
+      the error handling in particular made that too awkward, so
+      we (reluctantly) have a "copy" here.
+
+  RETURN VALUES
+    0	ok
+    1	error
+*/
+
 int
-sp_change_db(THD *thd, char *db, bool no_access_check)
+sp_change_db(THD *thd, char *name, bool no_access_check)
 {
-  int ret;
-  ulong dbaccess= thd->db_access; /* mysql_change_db() changes this */ 
-  my_bool nsok= thd->net.no_send_ok; /* mysql_change_db() does send_ok() */
-  thd->net.no_send_ok= TRUE;
+  int length, db_length;
+  char *dbname=my_strdup((char*) name,MYF(MY_WME));
+  char	path[FN_REFLEN];
+  ulong db_access;
+  HA_CREATE_INFO create;
   DBUG_ENTER("sp_change_db");
-  DBUG_PRINT("enter", ("db: %s, no_access_check: %d", db, no_access_check));
+  DBUG_PRINT("enter", ("db: %s, no_access_check: %d", name, no_access_check));
 
-  ret= mysql_change_db(thd, db, 1, no_access_check);
+  db_length= (!dbname ? 0 : strip_sp(dbname));
+  if (dbname && db_length)
+  {
+    if ((db_length > NAME_LEN) || check_db_name(dbname))
+    {
+      my_printf_error(ER_WRONG_DB_NAME, ER(ER_WRONG_DB_NAME), MYF(0), dbname);
+      x_free(dbname);
+      DBUG_RETURN(1);
+    }
+  }
 
-  thd->net.no_send_ok= nsok;
-  thd->db_access= dbaccess;
-  DBUG_RETURN(ret);
+  if (dbname && db_length)
+  {
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+    if (! no_access_check)
+    {
+      if (test_all_bits(thd->master_access,DB_ACLS))
+	db_access=DB_ACLS;
+      else
+	db_access= (acl_get(thd->host,thd->ip, thd->priv_user,dbname,0) |
+		    thd->master_access);  
+      if (!(db_access & DB_ACLS) &&
+	  (!grant_option || check_grant_db(thd,dbname)))
+      {
+	my_printf_error(ER_DBACCESS_DENIED_ERROR, ER(ER_DBACCESS_DENIED_ERROR),
+			MYF(0),
+			thd->priv_user,
+			thd->priv_host,
+			dbname);
+	mysql_log.write(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),
+			thd->priv_user,
+			thd->priv_host,
+			dbname);
+	my_free(dbname,MYF(0));
+	DBUG_RETURN(1);
+      }
+    }
+#endif
+    (void) sprintf(path,"%s/%s",mysql_data_home,dbname);
+    length=unpack_dirname(path,path);		// Convert if not unix
+    if (length && path[length-1] == FN_LIBCHAR)
+      path[length-1]=0;				// remove ending '\'
+    if (access(path,F_OK))
+    {
+      my_printf_error(ER_BAD_DB_ERROR, ER(ER_BAD_DB_ERROR), MYF(0), dbname);
+      my_free(dbname,MYF(0));
+      DBUG_RETURN(1);
+    }
+  }
+
+  x_free(thd->db);
+  thd->db=dbname;				// THD::~THD will free this
+  thd->db_length=db_length;
+
+  if (dbname && db_length)
+  {
+    strmov(path+unpack_dirname(path,path), MY_DB_OPT_FILE);
+    load_db_opt(thd, path, &create);
+    thd->db_charset= create.default_table_charset ?
+      create.default_table_charset :
+      thd->variables.collation_server;
+    thd->variables.collation_database= thd->db_charset;
+  }
+  DBUG_RETURN(0);
 }