222 lines
9.1 KiB
Ada
222 lines
9.1 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNU ADA RUNTIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- 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 --
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-- --
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-- B o d y --
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-- (Version for new GNARL) --
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-- --
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-- $Revision: 1.3 $ --
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-- --
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-- Copyright (C) 1991,1992,1993,1994,1995,1996 Florida State University --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNARL; see file COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. It is --
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-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
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-- State University (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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-- This is the FreeBSD PTHREADS version of this package
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-- This is only a first approximation.
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-- It should be autogenerated by the m4 macro processor.
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-- Contributed by Peter Burwood (gnat@arcangel.dircon.co.uk).
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-- This file performs the system-dependent translation between machine
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-- exceptions and the Ada exceptions, if any, that should be raised when
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-- they occur. This version works for FreeBSD. Contributed by
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-- Daniel M. Eischen (eischen@vigrid.com).
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-- PLEASE DO NOT add any dependences on other packages.
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-- This package is designed to work with or without tasking support.
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-- See the other warnings in the package specification before making
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-- any modifications to this file.
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-- Make a careful study of all signals available under the OS,
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-- to see which need to be reserved, kept always unmasked,
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-- or kept always unmasked.
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-- Be on the lookout for special signals that
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-- may be used by the thread library.
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with Interfaces.C;
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-- used for int and other types
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with System.OS_Interface;
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-- used for various Constants, Signal and types
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package body System.Interrupt_Management is
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use Interfaces.C;
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use System.OS_Interface;
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type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
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Exception_Interrupts : constant Interrupt_List :=
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(SIGFPE, SIGILL, SIGSEGV, SIGBUS);
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Unreserve_All_Interrupts : Interfaces.C.int;
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pragma Import
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(C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
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----------------------
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-- Notify_Exception --
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----------------------
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Signal_Mask : aliased sigset_t;
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-- The set of signals handled by Notify_Exception
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-- This function identifies the Ada exception to be raised using
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-- the information when the system received a synchronous signal.
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-- Since this function is machine and OS dependent, different code
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-- has to be provided for different target.
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-- Language specs say signal handlers take exactly one arg, even
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-- though FreeBSD actually supplies three. Ugh!
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procedure Notify_Exception
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(signo : Signal;
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code : Interfaces.C.int;
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context : access struct_sigcontext);
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procedure Notify_Exception
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(signo : Signal;
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code : Interfaces.C.int;
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context : access struct_sigcontext) is
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begin
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-- As long as we are using a longjmp to return control to the
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-- exception handler on the runtime stack, we are safe. The original
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-- signal mask (the one we had before coming into this signal catching
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-- function) will be restored by the longjmp. Therefore, raising
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-- an exception in this handler should be a safe operation.
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-- Check that treatment of exception propagation here
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-- is consistent with treatment of the abort signal in
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-- System.Task_Primitives.Operations.
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case signo is
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when SIGFPE =>
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raise Constraint_Error;
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when SIGILL =>
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raise Constraint_Error;
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when SIGSEGV =>
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raise Storage_Error;
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when SIGBUS =>
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raise Storage_Error;
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when others =>
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pragma Assert (False);
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null;
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end case;
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end Notify_Exception;
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---------------------------
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-- Initialize_Interrupts --
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---------------------------
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-- Nothing needs to be done on this platform.
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procedure Initialize_Interrupts is
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begin
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null;
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end Initialize_Interrupts;
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begin
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declare
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act : aliased struct_sigaction;
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old_act : aliased struct_sigaction;
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Result : Interfaces.C.int;
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begin
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Abort_Task_Interrupt := SIGABRT;
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-- Change this if you want to use another signal for task abort.
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-- SIGTERM might be a good one.
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act.sa_handler := Notify_Exception'Address;
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act.sa_flags := 16#010#;
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-- Set sa_flags to SA_NODEFER so that during the handler execution
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-- we do not change the Signal_Mask to be masked for the Signal.
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-- This is a temporary fix to the problem that the Signal_Mask is
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-- not restored after the exception (longjmp) from the handler.
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-- The right fix should be made in sigsetjmp so that we save
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-- the Signal_Set and restore it after a longjmp.
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-- In that case, this field should be changed back to 0. ???
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Result := sigemptyset (Signal_Mask'Access);
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pragma Assert (Result = 0);
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for I in Exception_Interrupts'Range loop
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Result :=
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sigaddset
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(Signal_Mask'Access, Signal (Exception_Interrupts (I)));
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pragma Assert (Result = 0);
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end loop;
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act.sa_mask := Signal_Mask;
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for I in Exception_Interrupts'Range loop
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Keep_Unmasked (Exception_Interrupts (I)) := True;
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Result :=
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sigaction
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(Signal (Exception_Interrupts (I)), act'Unchecked_Access,
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old_act'Unchecked_Access);
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pragma Assert (Result = 0);
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end loop;
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Keep_Unmasked (Abort_Task_Interrupt) := True;
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Keep_Unmasked (SIGSTOP) := True;
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Keep_Unmasked (SIGKILL) := True;
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-- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but in the
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-- same time, disable the ability of handling this signal
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-- via Ada.Interrupts.
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-- The pragma Unreserve_All_Interrupts let the user the ability to
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-- change this behavior.
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if Unreserve_All_Interrupts = 0 then
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Keep_Unmasked (SIGINT) := True;
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else
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Keep_Unmasked (SIGINT) := False;
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end if;
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-- FreeBSD uses SIGINFO to dump thread status to stdout. If
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-- the user really wants to attach his own handler, let him.
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-- FreeBSD pthreads uses setitimer/getitimer for thread scheduling.
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-- Specifically, it uses timer ITIMER_PROF which generates SIGPROF.
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-- FreeBSD pthreads also needs SIGCHLD. The FreeBSD threads library
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-- also uses SIGINFO for debugging, but it's not required so we'll
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-- let an Ada application use it.
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Keep_Unmasked (SIGCHLD) := True;
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Keep_Unmasked (SIGPROF) := True;
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Reserve := Reserve or Keep_Unmasked or Keep_Masked;
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Reserve (0) := true;
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-- We do not have Signal 0 in reality. We just use this value
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-- to identify non-existent signals (see s-intnam.ads). Therefore,
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-- Signal 0 should not be used in all signal related operations hence
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-- mark it as reserved.
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end;
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end System.Interrupt_Management;
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