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 --
11 -- Copyright (C) 1991-2001 Florida State University --
13 -- GNARL is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNARL; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNARL was developed by the GNARL team at Florida State University. It is --
32 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
33 -- State University (http://www.gnat.com). --
35 ------------------------------------------------------------------------------
37 -- This is the GNU/Linux version of this package
39 -- This file performs the system-dependent translation between machine
40 -- exceptions and the Ada exceptions, if any, that should be raised when they
41 -- occur. This version works for the x86 running linux.
43 -- This is a Sun OS (FSU THREADS) version of this package
45 -- PLEASE DO NOT add any dependences on other packages. ??? why not ???
46 -- This package is designed to work with or without tasking support.
48 -- Make a careful study of all signals available under the OS, to see which
49 -- need to be reserved, kept always unmasked, or kept always unmasked. Be on
50 -- the lookout for special signals that may be used by the thread library.
52 -- The definitions of "reserved" differ slightly between the ARM and POSIX.
53 -- Here is the ARM definition of reserved interrupt:
55 -- The set of reserved interrupts is implementation defined. A reserved
56 -- interrupt is either an interrupt for which user-defined handlers are not
57 -- supported, or one which already has an attached handler by some other
58 -- implementation-defined means. Program units can be connected to
59 -- non-reserved interrupts.
61 -- POSIX.5b/.5c specifies further:
63 -- Signals which the application cannot accept, and for which the application
64 -- cannot modify the signal action or masking, because the signals are
65 -- reserved for use by the Ada language implementation. The reserved signals
66 -- defined by this standard are Signal_Abort, Signal_Alarm,
67 -- Signal_Floating_Point_Error, Signal_Illegal_Instruction,
68 -- Signal_Segmentation_Violation, Signal_Bus_Error. If the implementation
69 -- supports any signals besides those defined by this standard, the
70 -- implementation may also reserve some of those.
72 -- The signals defined by POSIX.5b/.5c that are not specified as being
73 -- reserved are SIGHUP, SIGINT, SIGPIPE, SIGQUIT, SIGTERM, SIGUSR1, SIGUSR2,
74 -- SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGIO SIGURG, and all
75 -- the real-time signals.
77 -- Beware of reserving signals that POSIX.5b/.5c require to be available for
78 -- users. POSIX.5b/.5c say:
80 -- An implementation shall not impose restrictions on the ability of an
81 -- application to send, accept, block, or ignore the signals defined by this
82 -- standard, except as specified in this standard.
84 -- Here are some other relevant requirements from POSIX.5b/.5c:
86 -- For the environment task, the initial signal mask is that specified for
89 -- It is anticipated that the paragraph above may be modified by a future
90 -- revision of this standard, to require that the realtime signals always be
91 -- initially masked for a process that is an Ada active partition.
93 -- For all other tasks, the initial signal mask shall include all the signals
94 -- that are not reserved signals and are not bound to entries of the task.
97 -- used for int and other types
99 with System.Error_Reporting;
102 with System.OS_Interface;
103 -- used for various Constants, Signal and types
106 -- used for Exception_Id
107 -- Raise_From_Signal_Handler
109 with System.Soft_Links;
110 -- used for Get_Machine_State_Addr
112 with Unchecked_Conversion;
114 package body System.Interrupt_Management is
117 use System.Error_Reporting;
118 use System.OS_Interface;
120 package TSL renames System.Soft_Links;
122 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
123 Exception_Interrupts : constant Interrupt_List :=
124 (SIGFPE, SIGILL, SIGSEGV);
126 Unreserve_All_Interrupts : Interfaces.C.int;
128 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
130 subtype int is Interfaces.C.int;
131 subtype unsigned_short is Interfaces.C.unsigned_short;
132 subtype unsigned_long is Interfaces.C.unsigned_long;
134 ----------------------
135 -- Notify_Exception --
136 ----------------------
138 Signal_Mask : aliased sigset_t;
139 -- The set of signals handled by Notify_Exception
141 -- This function identifies the Ada exception to be raised using
142 -- the information when the system received a synchronous signal.
143 -- Since this function is machine and OS dependent, different code
144 -- has to be provided for different target.
146 procedure Notify_Exception
160 trapno : unsigned_long;
164 eflags : unsigned_long;
165 esp_at_signal : unsigned_long;
167 fpstate : System.Address;
168 oldmask : unsigned_long;
169 cr2 : unsigned_long);
171 procedure Notify_Exception
185 trapno : unsigned_long;
189 eflags : unsigned_long;
190 esp_at_signal : unsigned_long;
192 fpstate : System.Address;
193 oldmask : unsigned_long;
197 function To_Machine_State_Ptr is new
198 Unchecked_Conversion (Address, Machine_State_Ptr);
200 -- These are not directly visible
202 procedure Raise_From_Signal_Handler
203 (E : Ada.Exceptions.Exception_Id;
206 (Ada, Raise_From_Signal_Handler,
207 "ada__exceptions__raise_from_signal_handler");
208 pragma No_Return (Raise_From_Signal_Handler);
210 mstate : Machine_State_Ptr;
211 message : aliased constant String := "" & ASCII.Nul;
212 -- a null terminated String.
218 -- Raise_From_Signal_Handler makes sure that the exception is raised
219 -- safely from this signal handler.
221 -- ??? The original signal mask (the one we had before coming into this
222 -- signal catching function) should be restored by
223 -- Raise_From_Signal_Handler. For now, restore it explicitly
225 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
226 pragma Assert (Result = 0);
228 -- Check that treatment of exception propagation here
229 -- is consistent with treatment of the abort signal in
230 -- System.Task_Primitives.Operations.
232 mstate := To_Machine_State_Ptr (TSL.Get_Machine_State_Addr.all);
235 mstate.esp := esp_at_signal;
242 Raise_From_Signal_Handler
243 (Constraint_Error'Identity, message'Address);
245 Raise_From_Signal_Handler
246 (Constraint_Error'Identity, message'Address);
248 Raise_From_Signal_Handler
249 (Storage_Error'Identity, message'Address);
251 if Shutdown ("Unexpected signal") then
255 end Notify_Exception;
257 ---------------------------
258 -- Initialize_Interrupts --
259 ---------------------------
261 -- Nothing needs to be done on this platform.
263 procedure Initialize_Interrupts is
266 end Initialize_Interrupts;
270 act : aliased struct_sigaction;
271 old_act : aliased struct_sigaction;
276 -- Need to call pthread_init very early because it is doing signal
281 Abort_Task_Interrupt := SIGADAABORT;
283 act.sa_handler := Notify_Exception'Address;
286 -- On some targets, we set sa_flags to SA_NODEFER so that during the
287 -- handler execution we do not change the Signal_Mask to be masked for
289 -- This is a temporary fix to the problem that the Signal_Mask is
290 -- not restored after the exception (longjmp) from the handler.
291 -- The right fix should be made in sigsetjmp so that we save
292 -- the Signal_Set and restore it after a longjmp.
293 -- Since SA_NODEFER is obsolete, instead we reset explicitly
294 -- the mask in the exception handler.
296 Result := sigemptyset (Signal_Mask'Access);
297 pragma Assert (Result = 0);
299 for J in Exception_Interrupts'Range loop
301 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J)));
302 pragma Assert (Result = 0);
305 act.sa_mask := Signal_Mask;
309 (Signal (SIGFPE), act'Unchecked_Access,
310 old_act'Unchecked_Access);
311 pragma Assert (Result = 0);
313 for J in Exception_Interrupts'First + 1 .. Exception_Interrupts'Last loop
314 Keep_Unmasked (Exception_Interrupts (J)) := True;
315 if Unreserve_All_Interrupts = 0 then
318 (Signal (Exception_Interrupts (J)),
319 act'Unchecked_Access,
320 old_act'Unchecked_Access);
321 pragma Assert (Result = 0);
325 Keep_Unmasked (Abort_Task_Interrupt) := True;
326 Keep_Unmasked (SIGXCPU) := True;
327 Keep_Unmasked (SIGBUS) := True;
328 Keep_Unmasked (SIGFPE) := True;
330 -- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but in the
331 -- same time, disable the ability of handling this signal
332 -- via Ada.Interrupts.
333 -- The pragma Unreserve_All_Interrupts let the user the ability to
334 -- change this behavior.
336 if Unreserve_All_Interrupts = 0 then
337 Keep_Unmasked (SIGINT) := True;
340 for J in Unmasked'Range loop
341 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
344 Reserve := Keep_Unmasked or Keep_Masked;
346 for J in Reserved'Range loop
347 Reserve (Interrupt_ID (Reserved (J))) := True;
351 -- We do not have Signal 0 in reality. We just use this value
352 -- to identify non-existent signals (see s-intnam.ads). Therefore,
353 -- Signal 0 should not be used in all signal related operations hence
354 -- mark it as reserved.
357 end System.Interrupt_Management;