gcc/ada/5sintman.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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 --                                                                          --
  10 --          Copyright (C) 1992-2002 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
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  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
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  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  32 -- State University (http://www.gnat.com).                                  --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This is a Solaris version of this package.
  37
  38 --  PLEASE DO NOT add any dependences on other packages.
  39 --  This package is designed to work with or without tasking support.
  40
  41 --  Make a careful study of all signals available under the OS,
  42 --  to see which need to be reserved, kept always unmasked,
  43 --  or kept always unmasked.
  44
  45 --  Be on the lookout for special signals that
  46 --  may be used by the thread library.
  47
  48 with Interfaces.C;
  49 --  used for int
  50
  51 with System.OS_Interface;
  52 --  used for various Constants, Signal and types
  53
  54 package body System.Interrupt_Management is
  55
  56    use Interfaces.C;
  57    use System.OS_Interface;
  58
  59    type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
  60
  61    Exception_Interrupts : constant Interrupt_List :=
  62      (SIGFPE, SIGILL, SIGSEGV, SIGBUS);
  63
  64    Unreserve_All_Interrupts : Interfaces.C.int;
  65    pragma Import
  66      (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
  67
  68    ----------------------
  69    -- Notify_Exception --
  70    ----------------------
  71
  72    --  This function identifies the Ada exception to be raised using
  73    --  the information when the system received a synchronous signal.
  74    --  Since this function is machine and OS dependent, different code
  75    --  has to be provided for different target.
  76
  77    procedure Notify_Exception
  78      (signo   : Signal;
  79       info    : access siginfo_t;
  80       context : access ucontext_t);
  81
  82    procedure Notify_Exception
  83      (signo   : Signal;
  84       info    : access siginfo_t;
  85       context : access ucontext_t) is
  86    begin
  87       --  Check that treatment of exception propagation here
  88       --  is consistent with treatment of the abort signal in
  89       --  System.Task_Primitives.Operations.
  90
  91       case signo is
  92          when SIGFPE =>
  93             case info.si_code is
  94                when  FPE_INTDIV |
  95                      FPE_INTOVF |
  96                      FPE_FLTDIV |
  97                      FPE_FLTOVF |
  98                      FPE_FLTUND |
  99                      FPE_FLTRES |
 100                      FPE_FLTINV |
 101                      FPE_FLTSUB =>
 102
 103                   raise Constraint_Error;
 104
 105                when others =>
 106                   pragma Assert (False);
 107                   null;
 108             end case;
 109
 110          when SIGILL | SIGSEGV | SIGBUS  =>
 111             raise Storage_Error;
 112
 113          when others =>
 114             pragma Assert (False);
 115             null;
 116       end case;
 117    end Notify_Exception;
 118
 119    ---------------------------
 120    -- Initialize_Interrupts --
 121    ---------------------------
 122
 123    --  Nothing needs to be done on this platform.
 124
 125    procedure Initialize_Interrupts is
 126    begin
 127       null;
 128    end Initialize_Interrupts;
 129
 130 ----------------------------
 131 -- Package Initialization --
 132 ----------------------------
 133
 134 begin
 135    declare
 136       act     : aliased struct_sigaction;
 137       old_act : aliased struct_sigaction;
 138       mask    : aliased sigset_t;
 139       Result  : Interfaces.C.int;
 140
 141    begin
 142       --  Need to call pthread_init very early because it is doing signal
 143       --  initializations.
 144
 145       pthread_init;
 146
 147       --  Change this if you want to use another signal for task abort.
 148       --  SIGTERM might be a good one.
 149
 150       Abort_Task_Interrupt := SIGABRT;
 151
 152       act.sa_handler := Notify_Exception'Address;
 153
 154       --  Set sa_flags to SA_NODEFER so that during the handler execution
 155       --  we do not change the Signal_Mask to be masked for the Signal.
 156       --  This is a temporary fix to the problem that the Signal_Mask is
 157       --  not restored after the exception (longjmp) from the handler.
 158       --  The right fix should be made in sigsetjmp so that we save
 159       --  the Signal_Set and restore it after a longjmp.
 160
 161       --  In that case, this field should be changed back to 0. ??? (Dong-Ik)
 162
 163       act.sa_flags := 16;
 164
 165       Result := sigemptyset (mask'Access);
 166       pragma Assert (Result = 0);
 167
 168       --  ??? For the same reason explained above, we can't mask these
 169       --  signals because otherwise we won't be able to catch more than
 170       --  one signal.
 171
 172       act.sa_mask := mask;
 173
 174       Keep_Unmasked (Abort_Task_Interrupt) := True;
 175
 176       --  By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but in the
 177       --  same time, disable the ability of handling this signal
 178       --  via Ada.Interrupts.
 179       --  The pragma Unreserve_All_Interrupts let the user the ability to
 180       --  change this behavior.
 181
 182       if Unreserve_All_Interrupts = 0 then
 183          Keep_Unmasked (SIGINT) := True;
 184       end if;
 185
 186       for J in Exception_Interrupts'Range loop
 187          Keep_Unmasked (Exception_Interrupts (J)) := True;
 188          Result :=
 189            sigaction
 190            (Signal (Exception_Interrupts (J)), act'Unchecked_Access,
 191             old_act'Unchecked_Access);
 192          pragma Assert (Result = 0);
 193       end loop;
 194
 195       for J in Unmasked'Range loop
 196          Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
 197       end loop;
 198
 199       Reserve := Keep_Unmasked or Keep_Masked;
 200
 201       for J in Reserved'Range loop
 202          Reserve (Interrupt_ID (Reserved (J))) := True;
 203       end loop;
 204
 205       --  We do not have Signal 0 in reality. We just use this value
 206       --  to identify not existing signals (see s-intnam.ads). Therefore,
 207       --  Signal 0 should not be used in all signal related operations hence
 208       --  mark it as reserved.
 209
 210       Reserve (0) := True;
 211    end;
 212 end System.Interrupt_Management;