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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- SYSTEM.TASK_PRIMITIVES.OPERATIONS.SPECIFIC --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2019, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This is a VxWorks version of this package where foreign threads are
-- recognized. The implementation is based on VxWorks taskVarLib.
separate (System.Task_Primitives.Operations)
package body Specific is
ATCB_Key : aliased System.Address := System.Null_Address;
-- Key used to find the Ada Task_Id associated with a thread
ATCB_Key_Addr : System.Address := ATCB_Key'Address;
pragma Export (Ada, ATCB_Key_Addr, "__gnat_ATCB_key_addr");
-- Exported to support the temporary AE653 task registration
-- implementation. This mechanism is used to minimize impact on other
-- targets.
Stack_Limit : aliased System.Address;
pragma Import (C, Stack_Limit, "__gnat_stack_limit");
type Set_Stack_Limit_Proc_Acc is access procedure;
pragma Convention (C, Set_Stack_Limit_Proc_Acc);
Set_Stack_Limit_Hook : Set_Stack_Limit_Proc_Acc;
pragma Import (C, Set_Stack_Limit_Hook, "__gnat_set_stack_limit_hook");
-- Procedure to be called when a task is created to set stack limit if
-- limit checking is used.
----------------
-- Initialize --
----------------
procedure Initialize is
begin
null;
end Initialize;
-------------------
-- Is_Valid_Task --
-------------------
function Is_Valid_Task return Boolean is
begin
return taskVarGet (taskIdSelf, ATCB_Key'Access) /= ERROR;
end Is_Valid_Task;
---------
-- Set --
---------
procedure Set (Self_Id : Task_Id) is
Result : STATUS;
begin
-- If argument is null, destroy task specific data, to make API
-- consistent with other platforms, and thus compatible with the
-- shared version of s-tpoaal.adb.
if Self_Id = null then
Result := taskVarDelete (taskIdSelf, ATCB_Key'Access);
pragma Assert (Result /= ERROR);
return;
end if;
if not Is_Valid_Task then
Result := taskVarAdd (Self_Id.Common.LL.Thread, ATCB_Key'Access);
pragma Assert (Result = OK);
if Stack_Check_Limits
and then Result /= ERROR
and then Set_Stack_Limit_Hook /= null
then
-- This will be initialized from taskInfoGet() once the task is
-- is running.
Result :=
taskVarAdd (Self_Id.Common.LL.Thread, Stack_Limit'Access);
pragma Assert (Result /= ERROR);
end if;
end if;
Result :=
taskVarSet
(Self_Id.Common.LL.Thread,
ATCB_Key'Access,
To_Address (Self_Id));
pragma Assert (Result /= ERROR);
end Set;
----------
-- Self --
----------
-- To make Ada tasks and C threads interoperate better, we have added some
-- functionality to Self. Suppose a C main program (with threads) calls an
-- Ada procedure and the Ada procedure calls the tasking runtime system.
-- Eventually, a call will be made to self. Since the call is not coming
-- from an Ada task, there will be no corresponding ATCB.
-- What we do in Self is to catch references that do not come from
-- recognized Ada tasks, and create an ATCB for the calling thread.
-- The new ATCB will be "detached" from the normal Ada task master
-- hierarchy, much like the existing implicitly created signal-server
-- tasks.
function Self return Task_Id is
Result : constant Task_Id := To_Task_Id (ATCB_Key);
begin
if Result /= null then
return Result;
else
-- If the value is Null then it is a non-Ada task
return Register_Foreign_Thread;
end if;
end Self;
end Specific;
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