| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 1992-2022, 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 : constant 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; |
