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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) 1992-2009, 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 the SuSV3 threads 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.

--  Since this is a multi target file, the signal <-> exception mapping

--  is simple minded. If you need a more precise and target specific

--  signal handling, create a new s-intman.adb that will fit your needs.

--  This file assumes that:

--    SIGINT exists and will be kept unmasked unless the pragma

--     Unreserve_All_Interrupts is specified anywhere in the application.

--    System.OS_Interface contains the following:

--      SIGADAABORT: the signal that will be used to abort tasks.

--      Unmasked: the OS specific set of signals that should be unmasked in

--                all the threads. SIGADAABORT is unmasked by

--                default

--      Reserved: the OS specific set of signals that are reserved.

package body System.Interrupt_Management is

   use Interfaces.C;

   use System.OS_Interface;

   Unreserve_All_Interrupts : Interfaces.C.int;

   pragma Import

     (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");

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

   -- 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:

   User    : constant Character := 'u';

   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)

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

   -- Initialize --

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

   Initialized : Boolean := False;

   procedure Initialize is

   begin

      if Initialized then

         return;

      end if;

      Initialized := True;

      --  Need to call pthread_init very early because it is doing signal

      --  initializations.

      pthread_init;

      Abort_Task_Interrupt := SIGADAABORT;

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

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

      --  Process state of exception signals

      for J in Exception_Signals'Range loop

         declare

            Sig : constant Signal := Exception_Signals (J);

            Id : constant Interrupt_ID := Interrupt_ID (Sig);

         begin

            if State (Id) /= User then

               Keep_Unmasked (Id) := True;

               Reserve (Id) := True;

            end if;

         end;

      end loop;

      if State (Abort_Task_Interrupt) /= User then

         Keep_Unmasked (Abort_Task_Interrupt) := True;

         Reserve (Abort_Task_Interrupt) := True;

      end if;

      --  Set SIGINT to unmasked state as long as it is not in "User" state.

      --  Check for Unreserve_All_Interrupts last.

      if State (SIGINT) /= User then

         Keep_Unmasked (SIGINT) := True;

         Reserve (SIGINT) := True;

      end if;

      --  Check all signals for state that requires keeping them unmasked and

      --  reserved.

      for J in Interrupt_ID'Range loop

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

            Keep_Unmasked (J) := True;

            Reserve (J) := True;

         end if;

      end loop;

      --  Add the set of signals that must always be unmasked for this target

      for J in Unmasked'Range loop

         Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;

         Reserve (Interrupt_ID (Unmasked (J))) := True;

      end loop;

      --  Add target-specific reserved signals

      for J in Reserved'Range loop

         Reserve (Interrupt_ID (Reserved (J))) := True;

      end loop;

      --  Process pragma Unreserve_All_Interrupts. This overrides any settings

      --  due to pragma Interrupt_State:

      if Unreserve_All_Interrupts /= 0 then

         Keep_Unmasked (SIGINT) := False;

         Reserve (SIGINT) := False;

      end if;

      --  We do not really have Signal 0. We just use this value to identify

      --  non-existent signals (see s-intnam.ads). Therefore, Signal should not

      --  be used in all signal related operations hence mark it as reserved.

      Reserve (0) := True;

   end Initialize;

end System.Interrupt_Management;