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------------------------------------------------------------------------------
-- --
-- GNU ADA 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 --
-- --
-- $Revision: 1.14 $
-- --
-- Copyright (C) 1991-2001, Florida State University --
-- --
-- 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, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, 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. It is --
-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
-- State University (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This is the default version of this package
-- This is a Sun OS (FSU THREADS) version of this package
-- PLEASE DO NOT add any dependences on other packages. ??? why not ???
-- This package is designed to work with or without tasking support.
-- See the other warnings in the package specification before making
-- any modifications to this file.
-- 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:
--
-- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows:
-- SIGPFE => Constraint_Error
-- SIGILL => Program_Error
-- SIGSEGV => Storage_Error
-- SIGBUS => Storage_Error
--
-- 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.
with Interfaces.C;
-- used for int and other types
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");
-----------------------
-- Local Subprograms --
-----------------------
procedure Notify_Exception (signo : Signal);
-- 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.
----------------------
-- Notify_Exception --
----------------------
Signal_Mask : aliased sigset_t;
-- The set of signals handled by Notify_Exception
procedure Notify_Exception (signo : Signal) is
Result : Interfaces.C.int;
begin
-- With the __builtin_longjmp, the signal mask is not restored, so we
-- need to restore it explicitely.
Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
pragma Assert (Result = 0);
-- 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 =>
raise Constraint_Error;
when SIGILL =>
raise Program_Error;
when SIGSEGV =>
raise Storage_Error;
when SIGBUS =>
raise Storage_Error;
when others =>
null;
end case;
end Notify_Exception;
---------------------------
-- Initialize_Interrupts --
---------------------------
-- Nothing needs to be done on this platform.
procedure Initialize_Interrupts is
begin
null;
end Initialize_Interrupts;
-------------------------
-- Package Elaboration --
-------------------------
begin
declare
act : aliased struct_sigaction;
old_act : aliased struct_sigaction;
Result : Interfaces.C.int;
begin
-- Need to call pthread_init very early because it is doing signal
-- initializations.
pthread_init;
Abort_Task_Interrupt := SIGADAABORT;
act.sa_handler := Notify_Exception'Address;
act.sa_flags := 0;
-- On some targets, we 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.
-- Since SA_NODEFER is obsolete, instead we reset explicitely
-- the mask in the exception handler.
Result := sigemptyset (Signal_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 := Signal_Mask;
Keep_Unmasked (Abort_Task_Interrupt) := True;
Keep_Unmasked (SIGXCPU) := True;
Keep_Unmasked (SIGFPE) := True;
Result :=
sigaction
(Signal (SIGFPE), act'Unchecked_Access,
old_act'Unchecked_Access);
pragma Assert (Result = 0);
-- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but at
-- the same time, disable the ability of handling this signal via
-- package Ada.Interrupts.
-- The pragma Unreserve_All_Interrupts let the user the ability to
-- change this behavior.
if Unreserve_All_Interrupts = 0 then
Keep_Unmasked (SIGINT) := True;
end if;
for J in
Exception_Interrupts'First + 1 .. Exception_Interrupts'Last
loop
Keep_Unmasked (Exception_Interrupts (J)) := True;
if Unreserve_All_Interrupts = 0 then
Result :=
sigaction
(Signal (Exception_Interrupts (J)), act'Unchecked_Access,
old_act'Unchecked_Access);
pragma Assert (Result = 0);
end if;
end loop;
for J in Unmasked'Range loop
Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
end loop;
Reserve := Keep_Unmasked or Keep_Masked;
for J in Reserved'Range loop
Reserve (Interrupt_ID (Reserved (J))) := True;
end loop;
-- We do not have Signal 0 in reality. We just use this value
-- to identify non-existent 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;
end System.Interrupt_Management;
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