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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) 1992-2009, 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 3, or (at your option) any later ver- --
+-- sion. GNAT 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. --
+-- --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
+-- --
+-- GNARL was developed by the GNARL team at Florida State University. --
+-- Extensive contributions were provided by Ada Core Technologies, Inc. --
+-- --
+------------------------------------------------------------------------------
+
+-- This is the POSIX threads 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.
+
+-- 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 System.Task_Primitives;
+
+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 --
+ -----------------------
+
+ 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)
+
+ procedure Notify_Exception
+ (signo : Signal;
+ siginfo : System.Address;
+ ucontext : System.Address);
+ -- 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;
+ siginfo : System.Address;
+ ucontext : System.Address)
+ is
+ pragma Unreferenced (siginfo);
+
+ Result : Interfaces.C.int;
+
+ begin
+ -- With the __builtin_longjmp, the signal mask is not restored, so we
+ -- need to restore it explicitly.
+
+ Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
+ pragma Assert (Result = 0);
+
+ -- Perform the necessary context adjustments prior to a raise
+ -- from a signal handler.
+
+ Adjust_Context_For_Raise (signo, ucontext);
+
+ -- 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 --
+ ----------------
+
+ Initialized : Boolean := False;
+
+ procedure Initialize is
+ act : aliased struct_sigaction;
+ old_act : aliased struct_sigaction;
+ Result : System.OS_Interface.int;
+
+ Use_Alternate_Stack : constant Boolean :=
+ System.Task_Primitives.Alternate_Stack_Size /= 0;
+ -- Whether to use an alternate signal stack for stack overflows
+
+ begin
+ if Initialized then
+ return;
+ end if;
+
+ Initialized := True;
+
+ -- 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;
+
+ -- Setting SA_SIGINFO asks the kernel to pass more than just the signal
+ -- number argument to the handler when it is called. The set of extra
+ -- parameters includes a pointer to the interrupted context, which the
+ -- ZCX propagation scheme needs.
+
+ -- Most man pages for sigaction mention that sa_sigaction should be set
+ -- instead of sa_handler when SA_SIGINFO is on. In practice, the two
+ -- fields are actually union'ed and located at the same offset.
+
+ -- 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);
+
+ -- Add signals that map to Ada exceptions to the mask
+
+ for J in Exception_Interrupts'Range loop
+ if State (Exception_Interrupts (J)) /= Default then
+ Result :=
+ sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
+ pragma Assert (Result = 0);
+ end if;
+ end loop;
+
+ act.sa_mask := Signal_Mask;
+
+ pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
+ pragma Assert (Reserve = (Interrupt_ID'Range => False));
+
+ -- Process state of exception signals
+
+ 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
+ act.sa_flags := SA_SIGINFO;
+
+ if Use_Alternate_Stack
+ and then Exception_Interrupts (J) = SIGSEGV
+ then
+ act.sa_flags := act.sa_flags + SA_ONSTACK;
+ end if;
+
+ 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 is 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 really have Signal 0. We just use this value to identify
+ -- non-existent signals (see s-intnam.ads). Therefore, Signal should not
+ -- be used in all signal related operations hence mark it as reserved.
+
+ Reserve (0) := True;
+ end Initialize;
+
+end System.Interrupt_Management;