------------------------------------------------------------------------------ -- -- -- 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 -- -- -- -- Copyright (C) 1992-2003, 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 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. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is the POSIX 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 : System.OS_Interface.int; function State (Int : Interrupt_ID) return Character; pragma Import (C, State, "__gnat_get_interrupt_state"); -- Get interrupt state. Defined in a-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) 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 := SA_SIGINFO; -- 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 typically includes a pointer to a structure describing -- the interrupted context. Although the Notify_Exception handler does -- not use this information, it is actually required for the GCC/ZCX -- exception propagation scheme because on some targets (at least -- alpha-tru64), the structure contents are not even filled when this -- flag is not set. -- 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); -- 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 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 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;