1 ------------------------------------------------------------------------------
3 -- GNU ADA 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) 1992-2005, 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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 -- PLEASE DO NOT add any dependences on other packages. ??? why not ???
37 -- This package is designed to work with or without tasking support.
39 -- See the other warnings in the package specification before making
40 -- any modifications to this file.
42 -- Make a careful study of all signals available under the OS, to see which
43 -- need to be reserved, kept always unmasked, or kept always unmasked. Be on
44 -- the lookout for special signals that may be used by the thread library.
46 -- Since this is a multi target file, the signal <-> exception mapping
47 -- is simple minded. If you need a more precise and target specific
48 -- signal handling, create a new s-intman.adb that will fit your needs.
50 -- This file assumes that:
52 -- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows:
53 -- SIGPFE => Constraint_Error
54 -- SIGILL => Program_Error
55 -- SIGSEGV => Storage_Error
56 -- SIGBUS => Storage_Error
58 -- SIGINT exists and will be kept unmasked unless the pragma
59 -- Unreserve_All_Interrupts is specified anywhere in the application.
61 -- System.OS_Interface contains the following:
62 -- SIGADAABORT: the signal that will be used to abort tasks.
63 -- Unmasked: the OS specific set of signals that should be unmasked in
64 -- all the threads. SIGADAABORT is unmasked by
66 -- Reserved: the OS specific set of signals that are reserved.
69 -- used for int and other types
71 with System.OS_Interface;
72 -- used for various Constants, Signal and types
74 package body System.Interrupt_Management is
77 use System.OS_Interface;
79 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
80 Exception_Interrupts : constant Interrupt_List :=
81 (SIGFPE, SIGILL, SIGSEGV, SIGBUS);
83 Unreserve_All_Interrupts : Interfaces.C.int;
85 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
87 -----------------------
88 -- Local Subprograms --
89 -----------------------
91 procedure Notify_Exception
93 siginfo : System.Address;
94 ucontext : System.Address);
95 -- This function identifies the Ada exception to be raised using
96 -- the information when the system received a synchronous signal.
97 -- Since this function is machine and OS dependent, different code
98 -- has to be provided for different target.
100 ----------------------
101 -- Notify_Exception --
102 ----------------------
104 Signal_Mask : aliased sigset_t;
105 -- The set of signals handled by Notify_Exception
107 procedure Notify_Exception
109 siginfo : System.Address;
110 ucontext : System.Address)
112 pragma Unreferenced (siginfo);
114 -- The GCC unwinder requires adjustments to the signal's machine
115 -- context to be able to properly unwind through the signal handler.
116 -- This is achieved by the target specific subprogram below, provided
117 -- by init.c to be usable by the non-tasking handler also.
119 procedure Adjust_Context_For_Raise
121 ucontext : System.Address);
123 (C, Adjust_Context_For_Raise, "__gnat_adjust_context_for_raise");
125 Result : Interfaces.C.int;
128 -- With the __builtin_longjmp, the signal mask is not restored, so we
129 -- need to restore it explicitely.
131 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
132 pragma Assert (Result = 0);
134 -- Perform the necessary context adjustments required by the GCC/ZCX
135 -- unwinder, harmless in the SJLJ case.
137 Adjust_Context_For_Raise (signo, ucontext);
139 -- Check that treatment of exception propagation here
140 -- is consistent with treatment of the abort signal in
141 -- System.Task_Primitives.Operations.
145 raise Constraint_Error;
155 end Notify_Exception;
157 ---------------------------
158 -- Initialize_Interrupts --
159 ---------------------------
161 -- Nothing needs to be done on this platform.
163 procedure Initialize_Interrupts is
166 end Initialize_Interrupts;
168 -------------------------
169 -- Package Elaboration --
170 -------------------------
174 act : aliased struct_sigaction;
175 old_act : aliased struct_sigaction;
176 Result : System.OS_Interface.int;
178 function State (Int : Interrupt_ID) return Character;
179 pragma Import (C, State, "__gnat_get_interrupt_state");
180 -- Get interrupt state. Defined in a-init.c
181 -- The input argument is the interrupt number,
182 -- and the result is one of the following:
184 User : constant Character := 'u';
185 Runtime : constant Character := 'r';
186 Default : constant Character := 's';
187 -- 'n' this interrupt not set by any Interrupt_State pragma
188 -- 'u' Interrupt_State pragma set state to User
189 -- 'r' Interrupt_State pragma set state to Runtime
190 -- 's' Interrupt_State pragma set state to System (use "default"
194 -- Need to call pthread_init very early because it is doing signal
199 Abort_Task_Interrupt := SIGADAABORT;
201 act.sa_handler := Notify_Exception'Address;
203 act.sa_flags := SA_SIGINFO;
205 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal
206 -- number argument to the handler when it is called. The set of extra
207 -- parameters includes a pointer to the interrupted context, which the
208 -- ZCX propagation scheme needs.
210 -- Most man pages for sigaction mention that sa_sigaction should be set
211 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two
212 -- fields are actually union'ed and located at the same offset.
214 -- On some targets, we set sa_flags to SA_NODEFER so that during the
215 -- handler execution we do not change the Signal_Mask to be masked for
218 -- This is a temporary fix to the problem that the Signal_Mask is
219 -- not restored after the exception (longjmp) from the handler.
220 -- The right fix should be made in sigsetjmp so that we save
221 -- the Signal_Set and restore it after a longjmp.
223 -- Since SA_NODEFER is obsolete, instead we reset explicitely
224 -- the mask in the exception handler.
226 Result := sigemptyset (Signal_Mask'Access);
227 pragma Assert (Result = 0);
229 -- Add signals that map to Ada exceptions to the mask.
230 for J in Exception_Interrupts'Range loop
231 if State (Exception_Interrupts (J)) /= Default then
233 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
234 pragma Assert (Result = 0);
238 act.sa_mask := Signal_Mask;
240 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
241 pragma Assert (Reserve = (Interrupt_ID'Range => False));
243 -- Process state of exception signals
244 for J in Exception_Interrupts'Range loop
245 if State (Exception_Interrupts (J)) /= User then
246 Keep_Unmasked (Exception_Interrupts (J)) := True;
247 Reserve (Exception_Interrupts (J)) := True;
249 if State (Exception_Interrupts (J)) /= Default then
252 (Signal (Exception_Interrupts (J)), act'Unchecked_Access,
253 old_act'Unchecked_Access);
254 pragma Assert (Result = 0);
259 if State (Abort_Task_Interrupt) /= User then
260 Keep_Unmasked (Abort_Task_Interrupt) := True;
261 Reserve (Abort_Task_Interrupt) := True;
264 -- Set SIGINT to unmasked state as long as it is not in "User"
265 -- state. Check for Unreserve_All_Interrupts last
267 if State (SIGINT) /= User then
268 Keep_Unmasked (SIGINT) := True;
269 Reserve (SIGINT) := True;
272 -- Check all signals for state that requires keeping them
273 -- unmasked and reserved
275 for J in Interrupt_ID'Range loop
276 if State (J) = Default or else State (J) = Runtime then
277 Keep_Unmasked (J) := True;
282 -- Add the set of signals that must always be unmasked for this target
284 for J in Unmasked'Range loop
285 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
286 Reserve (Interrupt_ID (Unmasked (J))) := True;
289 -- Add target-specific reserved signals
291 for J in Reserved'Range loop
292 Reserve (Interrupt_ID (Reserved (J))) := True;
295 -- Process pragma Unreserve_All_Interrupts. This overrides any
296 -- settings due to pragma Interrupt_State:
298 if Unreserve_All_Interrupts /= 0 then
299 Keep_Unmasked (SIGINT) := False;
300 Reserve (SIGINT) := False;
303 -- We do not have Signal 0 in reality. We just use this value
304 -- to identify non-existent signals (see s-intnam.ads). Therefore,
305 -- Signal 0 should not be used in all signal related operations hence
306 -- mark it as reserved.
310 end System.Interrupt_Management;