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