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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: 1.15 $ --
-- --
-- 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 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.
-- 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.Error_Reporting;
-- used for Shutdown
with System.OS_Interface;
-- used for various Constants, Signal and types
package body System.Interrupt_Management is
use Interfaces.C;
use System.Error_Reporting;
use System.OS_Interface;
type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
Exception_Interrupts : constant Interrupt_List :=
(SIGFPE, SIGILL, SIGSEGV);
Unreserve_All_Interrupts : Interfaces.C.int;
pragma Import
(C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
-----------------------
-- Local Subprograms --
-----------------------
procedure Notify_Exception
(signo : Signal;
info : access siginfo_t;
context : access struct_sigcontext);
-- 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 --
----------------------
-- The following code is intended for SunOS on Sparcstation.
procedure Notify_Exception
(signo : Signal;
info : access siginfo_t;
context : access struct_sigcontext)
is
begin
-- As long as we are using a longjmp to return control to the
-- exception handler on the runtime stack, we are safe. The original
-- signal mask (the one we had before coming into this signal catching
-- function) will be restored by the longjmp. Therefore, raising
-- an exception in this handler should be a safe operation.
-- 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_INTOVF_TRAP |
FPE_STARTSIG_TRAP |
FPE_INTDIV_TRAP |
FPE_FLTDIV_TRAP |
FPE_FLTUND_TRAP |
FPE_FLTOPERR_TRAP |
FPE_FLTOVF_TRAP =>
raise Constraint_Error;
when others =>
pragma Assert (Shutdown ("Unexpected SIGFPE signal"));
null;
end case;
when SIGILL =>
case info.si_code is
when ILL_STACK |
ILL_ILLINSTR_FAULT |
ILL_PRIVINSTR_FAULT =>
raise Constraint_Error;
when others =>
pragma Assert (Shutdown ("Unexpected SIGILL signal"));
null;
end case;
when SIGSEGV =>
-- was caused by accessing a null pointer.
-- ???? Origin of this code is unclear, may be broken ???
if context.sc_o0 in 0 .. 16#2000# then
raise Constraint_Error;
else
raise Storage_Error;
end if;
when others =>
pragma Assert (Shutdown ("Unexpected signal"));
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;
mask : aliased sigset_t;
Result : Interfaces.C.int;
begin
-- Need to call pthread_init very early because it is doing signal
-- initializations.
pthread_init;
-- Change the following assignment to use another signal for task abort.
-- For example, SIGTERM might be a good one if SIGABRT is required for
-- use elsewhere.
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. ???
act.sa_flags := 16;
Result := sigemptyset (mask'Access);
pragma Assert (Result = 0);
for J in Exception_Interrupts'Range loop
Result := sigaddset (mask'Access, Signal (Exception_Interrupts (J)));
pragma Assert (Result = 0);
end loop;
act.sa_mask := mask;
for J in Exception_Interrupts'Range 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;
Keep_Unmasked (Abort_Task_Interrupt) := True;
Keep_Unmasked (SIGBUS) := True;
Keep_Unmasked (SIGFPE) := True;
Result :=
sigaction
(Signal (SIGFPE), act'Unchecked_Access,
old_act'Unchecked_Access);
Keep_Unmasked (SIGALRM) := True;
Keep_Unmasked (SIGSTOP) := True;
Keep_Unmasked (SIGKILL) := True;
Keep_Unmasked (SIGXCPU) := True;
-- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but at
-- the same time, disable the ability of handling this signal using
-- package Ada.Interrupts.
-- The pragma Unreserve_All_Interrupts allows the user the ability to
-- change this behavior.
if Unreserve_All_Interrupts = 0 then
Keep_Unmasked (SIGINT) := True;
end if;
-- Reserve this not to interfere with thread scheduling
-- ??? consider adding this to interrupt exceptions
-- Keep_Unmasked (SIGALRM) := True;
-- An earlier version had a comment about SIGALRM needing to be unmasked
-- in at least one thread for cond_timedwait to work.
-- It is unclear whether this is True for Solaris threads, FSU threads,
-- both, or maybe just an old version of FSU threads. ????
-- Following signals should not be disturbed. Found by experiment
Keep_Unmasked (SIGEMT) := True;
Keep_Unmasked (SIGCHLD) := True;
-- 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 := Reserve or Keep_Unmasked or Keep_Masked;
Reserve (0) := True;
end;
end System.Interrupt_Management;
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