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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 a Solaris 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;

--  used for int

with System.OS_Interface;

--  used for various Constants, Signal and types

package body System.Interrupt_Management is

   use Interfaces.C;

   use System.OS_Interface;

   type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;

   Exception_Interrupts : constant Interrupt_List :=

     (SIGFPE, SIGILL, SIGSEGV, SIGBUS);

   Unreserve_All_Interrupts : Interfaces.C.int;

   pragma Import

     (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");

   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)

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

   -- Notify_Exception --

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

   --  This function identifies the Ada exception to be raised using

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

   --  Since this function is machine and OS dependent, different code

   --  has to be provided for different target.

   procedure Notify_Exception

     (signo   : Signal;

      info    : access siginfo_t;

      context : access ucontext_t);

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

   -- Notify_Exception --

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

   procedure Notify_Exception

     (signo   : Signal;

      info    : access siginfo_t;

      context : access ucontext_t)

   is

      pragma Unreferenced (context);

   begin

      --  Check that treatment of exception propagation here

      --  is consistent with treatment of the abort signal in

      --  System.Task_Primitives.Operations.

      case signo is

         when SIGFPE =>

            case info.si_code is

               when  FPE_INTDIV |

                     FPE_INTOVF |

                     FPE_FLTDIV |

                     FPE_FLTOVF |

                     FPE_FLTUND |

                     FPE_FLTRES |

                     FPE_FLTINV |

                     FPE_FLTSUB =>

                  raise Constraint_Error;

               when others =>

                  pragma Assert (False);

                  null;

            end case;

         when SIGILL | SIGSEGV | SIGBUS  =>

            raise Storage_Error;

         when others =>

            pragma Assert (False);

            null;

      end case;

   end Notify_Exception;

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

   -- Initialize --

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

   Initialized : Boolean := False;

   procedure Initialize is

      act     : aliased struct_sigaction;

      old_act : aliased struct_sigaction;

      mask    : aliased sigset_t;

      Result  : Interfaces.C.int;

   begin

      if Initialized then

         return;

      end if;

      Initialized := True;

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

      --  initializations.

      pthread_init;

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

      --  SIGTERM might be a good one.

      Abort_Task_Interrupt := SIGABRT;

      act.sa_handler := Notify_Exception'Address;

      --  Set sa_flags to SA_NODEFER so that during the handler execution

      --  we do not change the Signal_Mask to be masked for the Signal.

      --  This is a temporary fix to the problem that the Signal_Mask is

      --  not restored after the exception (longjmp) from the handler.

      --  The right fix should be made in sigsetjmp so that we save

      --  the Signal_Set and restore it after a longjmp.

      --  In that case, this field should be changed back to 0. ??? (Dong-Ik)

      act.sa_flags := 16;

      Result := sigemptyset (mask'Access);

      pragma Assert (Result = 0);

      --  ??? For the same reason explained above, we can't mask these

      --  signals because otherwise we won't be able to catch more than

      --  one signal.

      act.sa_mask := mask;

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

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

      for J in Exception_Interrupts'Range loop

         if State (Exception_Interrupts (J)) /= User then

            Keep_Unmasked (Exception_Interrupts (J)) := True;

            Reserve (Exception_Interrupts (J)) := True;

            if State (Exception_Interrupts (J)) /= Default then

               Result :=

                 sigaction

                 (Signal (Exception_Interrupts (J)), act'Unchecked_Access,

                  old_act'Unchecked_Access);

               pragma Assert (Result = 0);

            end if;

         end if;

      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's

      --  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 have Signal 0 in reality. We just use this value

      --  to identify not existing signals (see s-intnam.ads). Therefore,

      --  Signal 0 should not be used in all signal related operations hence

      --  mark it as reserved.

      Reserve (0) := True;

   end Initialize;

end System.Interrupt_Management;