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------------------------------------------------------------------------------

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--           S Y S T E M . I N T E R R U P T _ M A N A G E M E N T          --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--          Copyright (C) 1992-2005 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 2,  or (at your option) any later ver- --

-- sion. GNARL 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.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNARL; see file COPYING.  If not, write --

-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --

-- Boston, MA 02110-1301, USA.                                              --

--                                                                          --

-- As a special exception,  if other files  instantiate  generics from this --

-- unit, or you link  this unit with other files  to produce an executable, --

-- this  unit  does not  by itself cause  the resulting  executable  to  be --

-- covered  by the  GNU  General  Public  License.  This exception does not --

-- however invalidate  any other reasons why  the executable file  might be --

-- covered by the  GNU Public License.                                      --

--                                                                          --

-- GNARL was developed by the GNARL team at Florida State University.       --

-- Extensive contributions were provided by Ada Core Technologies, Inc.     --

--                                                                          --

------------------------------------------------------------------------------

--  This is the VxWorks version of this package.

--  Make a careful study of all signals available under the OS,

--  to see which need to be reserved, kept always unmasked,

--  or kept always unmasked.

--  Be on the lookout for special signals that

--  may be used by the thread library.

with Interfaces.C;

with System.OS_Interface;

--  used for various Constants, Signal and types

package body System.Interrupt_Management is

   use System.OS_Interface;

   use type Interfaces.C.int;

   type Signal_List is array (Signal_ID range <>) of Signal_ID;

   Exception_Signals : constant Signal_List (1 .. 4) :=

                         (SIGFPE, SIGILL, SIGSEGV, SIGBUS);

   Exception_Action : aliased struct_sigaction;

   --  Keep this variable global so that it is initialized only once

   procedure Map_And_Raise_Exception (signo : Signal);

   pragma Import (C, Map_And_Raise_Exception, "__gnat_map_signal");

   --  Map signal to Ada exception and raise it.  Different versions

   --  of VxWorks need different mappings.

   -----------------------

   -- Local Subprograms --

   -----------------------

   function State (Int : Interrupt_ID) return Character;

   pragma Import (C, State, "__gnat_get_interrupt_state");

   --  Get interrupt state.  Defined in init.c

   --  The input argument is the interrupt number,

   --  and the result is one of the following:

   Runtime : constant Character := 'r';

   Default : constant Character := 's';

   --    'n'   this interrupt not set by any Interrupt_State pragma

   --    'u'   Interrupt_State pragma set state to User

   --    'r'   Interrupt_State pragma set state to Runtime

   --    's'   Interrupt_State pragma set state to System (use "default"

   --           system handler)

   procedure Notify_Exception (signo : Signal);

   --  Identify the Ada exception to be raised using

   --  the information when the system received a synchronous signal.

   ----------------------

   -- Notify_Exception --

   ----------------------

   procedure Notify_Exception (signo : Signal) is

      Mask   : aliased sigset_t;

      Result : int;

      pragma Unreferenced (Result);

   begin

      Result := pthread_sigmask (SIG_SETMASK, null, Mask'Unchecked_Access);

      Result := sigdelset (Mask'Access, signo);

      Result := pthread_sigmask (SIG_SETMASK, Mask'Unchecked_Access, null);

      Map_And_Raise_Exception (signo);

   end Notify_Exception;

   ---------------------------

   -- Initialize_Interrupts --

   ---------------------------

   --  Since there is no signal inheritance between VxWorks tasks, we need

   --  to initialize signal handling in each task.

   procedure Initialize_Interrupts is

      Result  : int;

      old_act : aliased struct_sigaction;

   begin

      for J in Exception_Signals'Range loop

         Result :=

           sigaction

             (Signal (Exception_Signals (J)), Exception_Action'Access,

              old_act'Unchecked_Access);

         pragma Assert (Result = 0);

      end loop;

   end Initialize_Interrupts;

   ----------------

   -- Initialize --

   ----------------

   Initialized : Boolean := False;

   procedure Initialize is

      mask   : aliased sigset_t;

      Result : int;

   begin

      if Initialized then

         return;

      end if;

      Initialized := True;

      --  Change this if you want to use another signal for task abort.

      --  SIGTERM might be a good one.

      Abort_Task_Signal := SIGABRT;

      Exception_Action.sa_handler := Notify_Exception'Address;

      Exception_Action.sa_flags := SA_ONSTACK;

      Result := sigemptyset (mask'Access);

      pragma Assert (Result = 0);

      for J in Exception_Signals'Range loop

         Result := sigaddset (mask'Access, Signal (Exception_Signals (J)));

         pragma Assert (Result = 0);

      end loop;

      Exception_Action.sa_mask := mask;

      --  Initialize hardware interrupt handling

      pragma Assert (Reserve = (Interrupt_ID'Range => False));

      --  Check all interrupts for state that requires keeping them reserved

      for J in Interrupt_ID'Range loop

         if State (J) = Default or else State (J) = Runtime then

            Reserve (J) := True;

         end if;

      end loop;

      --  Add exception signals to the set of unmasked signals

      for J in Exception_Signals'Range loop

         Keep_Unmasked (Exception_Signals (J)) := True;

      end loop;

      --  The abort signal must also be unmasked

      Keep_Unmasked (Abort_Task_Signal) := True;

   end Initialize;

end System.Interrupt_Management;