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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: 1.2 $
-- --
-- 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 GNU/Linux version of this package
-- This file performs the system-dependent translation between machine
-- exceptions and the Ada exceptions, if any, that should be raised when they
-- occur. This version works for the x86 running linux.
-- 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.
-- The definitions of "reserved" differ slightly between the ARM and POSIX.
-- Here is the ARM definition of reserved interrupt:
-- The set of reserved interrupts is implementation defined. A reserved
-- interrupt is either an interrupt for which user-defined handlers are not
-- supported, or one which already has an attached handler by some other
-- implementation-defined means. Program units can be connected to
-- non-reserved interrupts.
-- POSIX.5b/.5c specifies further:
-- Signals which the application cannot accept, and for which the application
-- cannot modify the signal action or masking, because the signals are
-- reserved for use by the Ada language implementation. The reserved signals
-- defined by this standard are Signal_Abort, Signal_Alarm,
-- Signal_Floating_Point_Error, Signal_Illegal_Instruction,
-- Signal_Segmentation_Violation, Signal_Bus_Error. If the implementation
-- supports any signals besides those defined by this standard, the
-- implementation may also reserve some of those.
-- The signals defined by POSIX.5b/.5c that are not specified as being
-- reserved are SIGHUP, SIGINT, SIGPIPE, SIGQUIT, SIGTERM, SIGUSR1, SIGUSR2,
-- SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGIO SIGURG, and all
-- the real-time signals.
-- Beware of reserving signals that POSIX.5b/.5c require to be available for
-- users. POSIX.5b/.5c say:
-- An implementation shall not impose restrictions on the ability of an
-- application to send, accept, block, or ignore the signals defined by this
-- standard, except as specified in this standard.
-- Here are some other relevant requirements from POSIX.5b/.5c:
-- For the environment task, the initial signal mask is that specified for
-- the process...
-- It is anticipated that the paragraph above may be modified by a future
-- revision of this standard, to require that the realtime signals always be
-- initially masked for a process that is an Ada active partition.
-- For all other tasks, the initial signal mask shall include all the signals
-- that are not reserved signals and are not bound to entries of the task.
with Interfaces.C;
-- used for int and other types
with System.Error_Reporting;
-- used for Shutdown
with System.OS_Interface;
-- used for various Constants, Signal and types
with Ada.Exceptions;
-- used for Exception_Id
-- Raise_From_Signal_Handler
with System.Soft_Links;
-- used for Get_Machine_State_Addr
with Unchecked_Conversion;
package body System.Interrupt_Management is
use Interfaces.C;
use System.Error_Reporting;
use System.OS_Interface;
package TSL renames System.Soft_Links;
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");
subtype int is Interfaces.C.int;
subtype unsigned_short is Interfaces.C.unsigned_short;
subtype unsigned_long is Interfaces.C.unsigned_long;
----------------------
-- Notify_Exception --
----------------------
Signal_Mask : aliased sigset_t;
-- The set of signals handled by 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;
gs : unsigned_short;
fs : unsigned_short;
es : unsigned_short;
ds : unsigned_short;
edi : unsigned_long;
esi : unsigned_long;
ebp : unsigned_long;
esp : unsigned_long;
ebx : unsigned_long;
edx : unsigned_long;
ecx : unsigned_long;
eax : unsigned_long;
trapno : unsigned_long;
err : unsigned_long;
eip : unsigned_long;
cs : unsigned_short;
eflags : unsigned_long;
esp_at_signal : unsigned_long;
ss : unsigned_short;
fpstate : System.Address;
oldmask : unsigned_long;
cr2 : unsigned_long);
procedure Notify_Exception
(signo : Signal;
gs : unsigned_short;
fs : unsigned_short;
es : unsigned_short;
ds : unsigned_short;
edi : unsigned_long;
esi : unsigned_long;
ebp : unsigned_long;
esp : unsigned_long;
ebx : unsigned_long;
edx : unsigned_long;
ecx : unsigned_long;
eax : unsigned_long;
trapno : unsigned_long;
err : unsigned_long;
eip : unsigned_long;
cs : unsigned_short;
eflags : unsigned_long;
esp_at_signal : unsigned_long;
ss : unsigned_short;
fpstate : System.Address;
oldmask : unsigned_long;
cr2 : unsigned_long)
is
function To_Machine_State_Ptr is new
Unchecked_Conversion (Address, Machine_State_Ptr);
-- These are not directly visible
procedure Raise_From_Signal_Handler
(E : Ada.Exceptions.Exception_Id;
M : System.Address);
pragma Import
(Ada, Raise_From_Signal_Handler,
"ada__exceptions__raise_from_signal_handler");
pragma No_Return (Raise_From_Signal_Handler);
mstate : Machine_State_Ptr;
message : aliased constant String := "" & ASCII.Nul;
-- a null terminated String.
Result : int;
begin
-- Raise_From_Signal_Handler makes sure that the exception is raised
-- safely from this signal handler.
-- ??? The original signal mask (the one we had before coming into this
-- signal catching function) should be restored by
-- Raise_From_Signal_Handler. For now, restore it explicitly
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.
mstate := To_Machine_State_Ptr (TSL.Get_Machine_State_Addr.all);
mstate.eip := eip;
mstate.ebx := ebx;
mstate.esp := esp_at_signal;
mstate.ebp := ebp;
mstate.esi := esi;
mstate.edi := edi;
case signo is
when SIGFPE =>
Raise_From_Signal_Handler
(Constraint_Error'Identity, message'Address);
when SIGILL =>
Raise_From_Signal_Handler
(Constraint_Error'Identity, message'Address);
when SIGSEGV =>
Raise_From_Signal_Handler
(Storage_Error'Identity, message'Address);
when others =>
if Shutdown ("Unexpected signal") then
null;
end if;
end case;
end Notify_Exception;
---------------------------
-- Initialize_Interrupts --
---------------------------
-- Nothing needs to be done on this platform.
procedure Initialize_Interrupts is
begin
null;
end Initialize_Interrupts;
begin
declare
act : aliased struct_sigaction;
old_act : aliased struct_sigaction;
Result : 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 explicitly
-- the mask in the exception handler.
Result := sigemptyset (Signal_Mask'Access);
pragma Assert (Result = 0);
for J in Exception_Interrupts'Range loop
Result :=
sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
pragma Assert (Result = 0);
end loop;
act.sa_mask := Signal_Mask;
Result :=
sigaction
(Signal (SIGFPE), act'Unchecked_Access,
old_act'Unchecked_Access);
pragma Assert (Result = 0);
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;
Keep_Unmasked (Abort_Task_Interrupt) := True;
Keep_Unmasked (SIGXCPU) := True;
Keep_Unmasked (SIGBUS) := True;
Keep_Unmasked (SIGFPE) := True;
-- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but in the
-- same time, disable the ability of handling this signal
-- via 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 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;
Reserve (0) := True;
-- 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.
end;
end System.Interrupt_Management;