1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNARL is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 -- This is the POSIX threads version of this package
36 -- Make a careful study of all signals available under the OS, to see which
37 -- need to be reserved, kept always unmasked, or kept always unmasked. Be on
38 -- the lookout for special signals that may be used by the thread library.
40 -- Since this is a multi target file, the signal <-> exception mapping
41 -- is simple minded. If you need a more precise and target specific
42 -- signal handling, create a new s-intman.adb that will fit your needs.
44 -- This file assumes that:
46 -- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows:
47 -- SIGPFE => Constraint_Error
48 -- SIGILL => Program_Error
49 -- SIGSEGV => Storage_Error
50 -- SIGBUS => Storage_Error
52 -- SIGINT exists and will be kept unmasked unless the pragma
53 -- Unreserve_All_Interrupts is specified anywhere in the application.
55 -- System.OS_Interface contains the following:
56 -- SIGADAABORT: the signal that will be used to abort tasks.
57 -- Unmasked: the OS specific set of signals that should be unmasked in
58 -- all the threads. SIGADAABORT is unmasked by
60 -- Reserved: the OS specific set of signals that are reserved.
62 package body System.Interrupt_Management is
65 use System.OS_Interface;
67 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
68 Exception_Interrupts : constant Interrupt_List :=
69 (SIGFPE, SIGILL, SIGSEGV, SIGBUS);
71 Unreserve_All_Interrupts : Interfaces.C.int;
73 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
75 -----------------------
76 -- Local Subprograms --
77 -----------------------
79 function State (Int : Interrupt_ID) return Character;
80 pragma Import (C, State, "__gnat_get_interrupt_state");
81 -- Get interrupt state. Defined in init.c The input argument is the
82 -- interrupt number, and the result is one of the following:
84 User : constant Character := 'u';
85 Runtime : constant Character := 'r';
86 Default : constant Character := 's';
87 -- 'n' this interrupt not set by any Interrupt_State pragma
88 -- 'u' Interrupt_State pragma set state to User
89 -- 'r' Interrupt_State pragma set state to Runtime
90 -- 's' Interrupt_State pragma set state to System (use "default"
93 procedure Notify_Exception
95 siginfo : System.Address;
96 ucontext : System.Address);
97 -- This function identifies the Ada exception to be raised using the
98 -- information when the system received a synchronous signal. Since this
99 -- function is machine and OS dependent, different code has to be provided
100 -- for different target.
102 ----------------------
103 -- Notify_Exception --
104 ----------------------
106 Signal_Mask : aliased sigset_t;
107 -- The set of signals handled by Notify_Exception
109 procedure Notify_Exception
111 siginfo : System.Address;
112 ucontext : System.Address)
114 pragma Unreferenced (siginfo);
116 Result : Interfaces.C.int;
119 -- With the __builtin_longjmp, the signal mask is not restored, so we
120 -- need to restore it explicitely.
122 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
123 pragma Assert (Result = 0);
125 -- Perform the necessary context adjustments prior to a raise
126 -- from a signal handler.
128 Adjust_Context_For_Raise (signo, ucontext);
130 -- Check that treatment of exception propagation here is consistent with
131 -- treatment of the abort signal in System.Task_Primitives.Operations.
135 raise Constraint_Error;
145 end Notify_Exception;
151 Initialized : Boolean := False;
153 procedure Initialize is
154 act : aliased struct_sigaction;
155 old_act : aliased struct_sigaction;
156 Result : System.OS_Interface.int;
165 -- Need to call pthread_init very early because it is doing signal
170 Abort_Task_Interrupt := SIGADAABORT;
172 act.sa_handler := Notify_Exception'Address;
174 act.sa_flags := SA_SIGINFO;
176 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal
177 -- number argument to the handler when it is called. The set of extra
178 -- parameters includes a pointer to the interrupted context, which the
179 -- ZCX propagation scheme needs.
181 -- Most man pages for sigaction mention that sa_sigaction should be set
182 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two
183 -- fields are actually union'ed and located at the same offset.
185 -- On some targets, we set sa_flags to SA_NODEFER so that during the
186 -- handler execution we do not change the Signal_Mask to be masked for
189 -- This is a temporary fix to the problem that the Signal_Mask is not
190 -- restored after the exception (longjmp) from the handler. The right
191 -- fix should be made in sigsetjmp so that we save the Signal_Set and
192 -- restore it after a longjmp.
194 -- Since SA_NODEFER is obsolete, instead we reset explicitely the mask
195 -- in the exception handler.
197 Result := sigemptyset (Signal_Mask'Access);
198 pragma Assert (Result = 0);
200 -- Add signals that map to Ada exceptions to the mask
202 for J in Exception_Interrupts'Range loop
203 if State (Exception_Interrupts (J)) /= Default then
205 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
206 pragma Assert (Result = 0);
210 act.sa_mask := Signal_Mask;
212 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
213 pragma Assert (Reserve = (Interrupt_ID'Range => False));
215 -- Process state of exception signals
217 for J in Exception_Interrupts'Range loop
218 if State (Exception_Interrupts (J)) /= User then
219 Keep_Unmasked (Exception_Interrupts (J)) := True;
220 Reserve (Exception_Interrupts (J)) := True;
222 if State (Exception_Interrupts (J)) /= Default then
225 (Signal (Exception_Interrupts (J)), act'Unchecked_Access,
226 old_act'Unchecked_Access);
227 pragma Assert (Result = 0);
232 if State (Abort_Task_Interrupt) /= User then
233 Keep_Unmasked (Abort_Task_Interrupt) := True;
234 Reserve (Abort_Task_Interrupt) := True;
237 -- Set SIGINT to unmasked state as long as it is not in "User" state.
238 -- Check for Unreserve_All_Interrupts last
240 if State (SIGINT) /= User then
241 Keep_Unmasked (SIGINT) := True;
242 Reserve (SIGINT) := True;
245 -- Check all signals for state that requires keeping them unmasked and
248 for J in Interrupt_ID'Range loop
249 if State (J) = Default or else State (J) = Runtime then
250 Keep_Unmasked (J) := True;
255 -- Add the set of signals that must always be unmasked for this target
257 for J in Unmasked'Range loop
258 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
259 Reserve (Interrupt_ID (Unmasked (J))) := True;
262 -- Add target-specific reserved signals
264 for J in Reserved'Range loop
265 Reserve (Interrupt_ID (Reserved (J))) := True;
268 -- Process pragma Unreserve_All_Interrupts. This overrides any settings
269 -- due to pragma Interrupt_State:
271 if Unreserve_All_Interrupts /= 0 then
272 Keep_Unmasked (SIGINT) := False;
273 Reserve (SIGINT) := False;
276 -- We do not really have Signal 0. We just use this value to identify
277 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not
278 -- be used in all signal related operations hence mark it as reserved.
283 end System.Interrupt_Management;