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gcc-8.2
author mir3636
date Thu, 25 Oct 2018 07:37:49 +0900
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
4 -- --
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 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
10 -- --
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 3, or (at your option) any later ver- --
14 -- sion. GNAT 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. --
17 -- --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This is the QNX/Neutrino threads version of this package
33
34 -- Make a careful study of all signals available under the OS, to see which
35 -- need to be reserved, kept always unmasked, or kept always unmasked. Be on
36 -- the lookout for special signals that may be used by the thread library.
37
38 -- Since this is a multi target file, the signal <-> exception mapping
39 -- is simple minded. If you need a more precise and target specific
40 -- signal handling, create a new s-intman.adb that will fit your needs.
41
42 -- This file assumes that:
43
44 -- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows:
45 -- SIGPFE => Constraint_Error
46 -- SIGILL => Program_Error
47 -- SIGSEGV => Storage_Error
48 -- SIGBUS => Storage_Error
49
50 -- SIGINT exists and will be kept unmasked unless the pragma
51 -- Unreserve_All_Interrupts is specified anywhere in the application.
52
53 -- System.OS_Interface contains the following:
54 -- SIGADAABORT: the signal that will be used to abort tasks.
55 -- Unmasked: the OS specific set of signals that should be unmasked in
56 -- all the threads. SIGADAABORT is unmasked by
57 -- default
58 -- Reserved: the OS specific set of signals that are reserved.
59
60 with System.Task_Primitives;
61
62 package body System.Interrupt_Management is
63
64 use Interfaces.C;
65 use System.OS_Interface;
66
67 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
68 Exception_Interrupts : constant Interrupt_List :=
69 (SIGFPE, SIGILL, SIGSEGV, SIGBUS);
70
71 Unreserve_All_Interrupts : Interfaces.C.int;
72 pragma Import
73 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
74
75 -----------------------
76 -- Local Subprograms --
77 -----------------------
78
79 procedure Signal_Trampoline
80 (signo : Signal;
81 siginfo : System.Address;
82 ucontext : System.Address;
83 handler : System.Address);
84 pragma Import (C, Signal_Trampoline, "__gnat_sigtramp");
85 -- Pass the real handler to a speical function that handles unwinding by
86 -- skipping over the kernel signal frame (which doesn't contain any unwind
87 -- information).
88
89 procedure Map_Signal
90 (signo : Signal;
91 siginfo : System.Address;
92 ucontext : System.Address);
93 pragma Import (C, Map_Signal, "__gnat_map_signal");
94
95 function State (Int : Interrupt_ID) return Character;
96 pragma Import (C, State, "__gnat_get_interrupt_state");
97 -- Get interrupt state. Defined in init.c The input argument is the
98 -- interrupt number, and the result is one of the following:
99
100 User : constant Character := 'u';
101 Runtime : constant Character := 'r';
102 Default : constant Character := 's';
103 -- 'n' this interrupt not set by any Interrupt_State pragma
104 -- 'u' Interrupt_State pragma set state to User
105 -- 'r' Interrupt_State pragma set state to Runtime
106 -- 's' Interrupt_State pragma set state to System (use "default"
107 -- system handler)
108
109 procedure Notify_Exception
110 (signo : Signal;
111 siginfo : System.Address;
112 ucontext : System.Address);
113 -- This function identifies the Ada exception to be raised using the
114 -- information when the system received a synchronous signal. Since this
115 -- function is machine and OS dependent, different code has to be provided
116 -- for different target.
117
118 ----------------------
119 -- Notify_Exception --
120 ----------------------
121
122 Signal_Mask : aliased sigset_t;
123 -- The set of signals handled by Notify_Exception
124
125 procedure Notify_Exception
126 (signo : Signal;
127 siginfo : System.Address;
128 ucontext : System.Address)
129 is
130 Result : Interfaces.C.int;
131
132 begin
133 -- With the __builtin_longjmp, the signal mask is not restored, so we
134 -- need to restore it explicitly.
135
136 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
137 pragma Assert (Result = 0);
138
139 -- Perform the necessary context adjustments prior to a raise
140 -- from a signal handler.
141
142 Adjust_Context_For_Raise (signo, ucontext);
143
144 -- Check that treatment of exception propagation here is consistent with
145 -- treatment of the abort signal in System.Task_Primitives.Operations.
146
147 Signal_Trampoline (signo, siginfo, ucontext, Map_Signal'Address);
148 end Notify_Exception;
149
150 ----------------
151 -- Initialize --
152 ----------------
153
154 Initialized : Boolean := False;
155
156 procedure Initialize is
157 act : aliased struct_sigaction;
158 old_act : aliased struct_sigaction;
159 Result : System.OS_Interface.int;
160
161 Use_Alternate_Stack : constant Boolean :=
162 System.Task_Primitives.Alternate_Stack_Size /= 0;
163 -- Whether to use an alternate signal stack for stack overflows
164
165 begin
166 if Initialized then
167 return;
168 end if;
169
170 Initialized := True;
171
172 -- Need to call pthread_init very early because it is doing signal
173 -- initializations.
174
175 pthread_init;
176
177 Abort_Task_Interrupt := SIGADAABORT;
178
179 act.sa_handler := Notify_Exception'Address;
180
181 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal
182 -- number argument to the handler when it is called. The set of extra
183 -- parameters includes a pointer to the interrupted context, which the
184 -- ZCX propagation scheme needs.
185
186 -- Most man pages for sigaction mention that sa_sigaction should be set
187 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two
188 -- fields are actually union'ed and located at the same offset.
189
190 -- On some targets, we set sa_flags to SA_NODEFER so that during the
191 -- handler execution we do not change the Signal_Mask to be masked for
192 -- the Signal.
193
194 -- This is a temporary fix to the problem that the Signal_Mask is not
195 -- restored after the exception (longjmp) from the handler. The right
196 -- fix should be made in sigsetjmp so that we save the Signal_Set and
197 -- restore it after a longjmp.
198
199 -- Since SA_NODEFER is obsolete, instead we reset explicitly the mask
200 -- in the exception handler.
201
202 Result := sigemptyset (Signal_Mask'Access);
203 pragma Assert (Result = 0);
204
205 -- Add signals that map to Ada exceptions to the mask
206
207 for J in Exception_Interrupts'Range loop
208 if State (Exception_Interrupts (J)) /= Default then
209 Result :=
210 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
211 pragma Assert (Result = 0);
212 end if;
213 end loop;
214
215 act.sa_mask := Signal_Mask;
216
217 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
218 pragma Assert (Reserve = (Interrupt_ID'Range => False));
219
220 -- Process state of exception signals
221
222 for J in Exception_Interrupts'Range loop
223 if State (Exception_Interrupts (J)) /= User then
224 Keep_Unmasked (Exception_Interrupts (J)) := True;
225 Reserve (Exception_Interrupts (J)) := True;
226
227 if State (Exception_Interrupts (J)) /= Default then
228 act.sa_flags := SA_SIGINFO;
229
230 if Use_Alternate_Stack
231 and then Exception_Interrupts (J) = SIGSEGV
232 then
233 act.sa_flags := act.sa_flags + SA_ONSTACK;
234 end if;
235
236 Result :=
237 sigaction
238 (Signal (Exception_Interrupts (J)), act'Unchecked_Access,
239 old_act'Unchecked_Access);
240 pragma Assert (Result = 0);
241 end if;
242 end if;
243 end loop;
244
245 if State (Abort_Task_Interrupt) /= User then
246 Keep_Unmasked (Abort_Task_Interrupt) := True;
247 Reserve (Abort_Task_Interrupt) := True;
248 end if;
249
250 -- Set SIGINT to unmasked state as long as it is not in "User" state.
251 -- Check for Unreserve_All_Interrupts last.
252
253 if State (SIGINT) /= User then
254 Keep_Unmasked (SIGINT) := True;
255 Reserve (SIGINT) := True;
256 end if;
257
258 -- Check all signals for state that requires keeping them unmasked and
259 -- reserved.
260
261 for J in Interrupt_ID'Range loop
262 if State (J) = Default or else State (J) = Runtime then
263 Keep_Unmasked (J) := True;
264 Reserve (J) := True;
265 end if;
266 end loop;
267
268 -- Add the set of signals that must always be unmasked for this target
269
270 for J in Unmasked'Range loop
271 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
272 Reserve (Interrupt_ID (Unmasked (J))) := True;
273 end loop;
274
275 -- Add target-specific reserved signals
276
277 if Reserved'Length > 0 then
278 for J in Reserved'Range loop
279 Reserve (Interrupt_ID (Reserved (J))) := True;
280 end loop;
281 end if;
282
283 -- Process pragma Unreserve_All_Interrupts. This overrides any settings
284 -- due to pragma Interrupt_State:
285
286 if Unreserve_All_Interrupts /= 0 then
287 Keep_Unmasked (SIGINT) := False;
288 Reserve (SIGINT) := False;
289 end if;
290
291 -- We do not really have Signal 0. We just use this value to identify
292 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not
293 -- be used in all signal related operations hence mark it as reserved.
294
295 Reserve (0) := True;
296 end Initialize;
297
298 end System.Interrupt_Management;