gcc/ada/s-intman-susv3.adb

   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) 1992-2009, 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 SuSV3 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 --    SIGINT exists and will be kept unmasked unless the pragma
  45 --     Unreserve_All_Interrupts is specified anywhere in the application.
  46
  47 --    System.OS_Interface contains the following:
  48 --      SIGADAABORT: the signal that will be used to abort tasks.
  49 --      Unmasked: the OS specific set of signals that should be unmasked in
  50 --                all the threads. SIGADAABORT is unmasked by
  51 --                default
  52 --      Reserved: the OS specific set of signals that are reserved.
  53
  54 package body System.Interrupt_Management is
  55
  56    use Interfaces.C;
  57    use System.OS_Interface;
  58
  59    Unreserve_All_Interrupts : Interfaces.C.int;
  60    pragma Import
  61      (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
  62
  63    -----------------------
  64    -- Local Subprograms --
  65    -----------------------
  66
  67    function State (Int : Interrupt_ID) return Character;
  68    pragma Import (C, State, "__gnat_get_interrupt_state");
  69    --  Get interrupt state. Defined in init.c The input argument is the
  70    --  interrupt number, and the result is one of the following:
  71
  72    User    : constant Character := 'u';
  73    Runtime : constant Character := 'r';
  74    Default : constant Character := 's';
  75    --    'n'   this interrupt not set by any Interrupt_State pragma
  76    --    'u'   Interrupt_State pragma set state to User
  77    --    'r'   Interrupt_State pragma set state to Runtime
  78    --    's'   Interrupt_State pragma set state to System (use "default"
  79    --           system handler)
  80
  81    ----------------
  82    -- Initialize --
  83    ----------------
  84
  85    Initialized : Boolean := False;
  86
  87    procedure Initialize is
  88    begin
  89       if Initialized then
  90          return;
  91       end if;
  92
  93       Initialized := True;
  94
  95       --  Need to call pthread_init very early because it is doing signal
  96       --  initializations.
  97
  98       pthread_init;
  99
 100       Abort_Task_Interrupt := SIGADAABORT;
 101
 102       pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
 103       pragma Assert (Reserve = (Interrupt_ID'Range => False));
 104
 105       --  Process state of exception signals
 106
 107       for J in Exception_Signals'Range loop
 108          declare
 109             Sig : constant Signal := Exception_Signals (J);
 110             Id : constant Interrupt_ID := Interrupt_ID (Sig);
 111          begin
 112             if State (Id) /= User then
 113                Keep_Unmasked (Id) := True;
 114                Reserve (Id) := True;
 115             end if;
 116          end;
 117       end loop;
 118
 119       if State (Abort_Task_Interrupt) /= User then
 120          Keep_Unmasked (Abort_Task_Interrupt) := True;
 121          Reserve (Abort_Task_Interrupt) := True;
 122       end if;
 123
 124       --  Set SIGINT to unmasked state as long as it is not in "User" state.
 125       --  Check for Unreserve_All_Interrupts last.
 126
 127       if State (SIGINT) /= User then
 128          Keep_Unmasked (SIGINT) := True;
 129          Reserve (SIGINT) := True;
 130       end if;
 131
 132       --  Check all signals for state that requires keeping them unmasked and
 133       --  reserved.
 134
 135       for J in Interrupt_ID'Range loop
 136          if State (J) = Default or else State (J) = Runtime then
 137             Keep_Unmasked (J) := True;
 138             Reserve (J) := True;
 139          end if;
 140       end loop;
 141
 142       --  Add the set of signals that must always be unmasked for this target
 143
 144       for J in Unmasked'Range loop
 145          Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
 146          Reserve (Interrupt_ID (Unmasked (J))) := True;
 147       end loop;
 148
 149       --  Add target-specific reserved signals
 150
 151       for J in Reserved'Range loop
 152          Reserve (Interrupt_ID (Reserved (J))) := True;
 153       end loop;
 154
 155       --  Process pragma Unreserve_All_Interrupts. This overrides any settings
 156       --  due to pragma Interrupt_State:
 157
 158       if Unreserve_All_Interrupts /= 0 then
 159          Keep_Unmasked (SIGINT) := False;
 160          Reserve (SIGINT) := False;
 161       end if;
 162
 163       --  We do not really have Signal 0. We just use this value to identify
 164       --  non-existent signals (see s-intnam.ads). Therefore, Signal should not
 165       --  be used in all signal related operations hence mark it as reserved.
 166
 167       Reserve (0) := True;
 168    end Initialize;
 169
 170 end System.Interrupt_Management;