gcc/ada/5gintman.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) 1991-1994, Florida State University            --
  10 --             Copyright (C) 1995-2003, Ada Core Technologies               --
  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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  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  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 --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  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.       --
  31 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This is an Irix (old pthread library) version of this package.
  36
  37 --  PLEASE DO NOT add any dependences on other packages.
  38 --  This package is designed to work with or without tasking support.
  39
  40 --  Make a careful study of all signals available under the OS,
  41 --  to see which need to be reserved, kept always unmasked,
  42 --  or kept always unmasked.
  43
  44 --  Be on the lookout for special signals that
  45 --  may be used by the thread library.
  46
  47 with System.OS_Interface;
  48 --  used for various Constants, Signal and types
  49
  50 with Interfaces.C;
  51 --  used for "int"
  52 package body System.Interrupt_Management is
  53
  54    use System.OS_Interface;
  55
  56    type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
  57
  58    Exception_Interrupts : constant Interrupt_List :=
  59      (SIGILL,
  60       SIGABRT,
  61       SIGFPE,
  62       SIGSEGV,
  63       SIGBUS);
  64
  65    Reserved_Interrupts : constant Interrupt_List :=
  66      (0,
  67       SIGTRAP,
  68       SIGKILL,
  69       SIGSYS,
  70       SIGALRM,
  71       SIGSTOP,
  72       SIGPTINTR,
  73       SIGPTRESCHED);
  74
  75    Abort_Signal : constant := 48;
  76    --
  77    --  Serious MOJO:  The SGI pthreads library only supports the
  78    --                 unnamed signal number 48 for pthread_kill!
  79    --
  80
  81    Unreserve_All_Interrupts : Interfaces.C.int;
  82    pragma Import
  83      (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
  84
  85    ----------------------
  86    -- Notify_Exception --
  87    ----------------------
  88
  89    --  This function identifies the Ada exception to be raised using the
  90    --  information when the system received a synchronous signal.
  91    --  Since this function is machine and OS dependent, different code has to
  92    --  be provided for different target.
  93    --  On SGI, the signal handling is done is a-init.c, even when tasking is
  94    --  involved.
  95
  96    ---------------------------
  97    -- Initialize_Interrupts --
  98    ---------------------------
  99
 100    --  Nothing needs to be done on this platform.
 101
 102    procedure Initialize_Interrupts is
 103    begin
 104       null;
 105    end Initialize_Interrupts;
 106
 107 begin
 108    declare
 109       function State (Int : Interrupt_ID) return Character;
 110       pragma Import (C, State, "__gnat_get_interrupt_state");
 111       --  Get interrupt state.  Defined in a-init.c
 112       --  The input argument is the interrupt number,
 113       --  and the result is one of the following:
 114
 115       User    : constant Character := 'u';
 116       Runtime : constant Character := 'r';
 117       Default : constant Character := 's';
 118       --    'n'   this interrupt not set by any Interrupt_State pragma
 119       --    'u'   Interrupt_State pragma set state to User
 120       --    'r'   Interrupt_State pragma set state to Runtime
 121       --    's'   Interrupt_State pragma set state to System (use "default"
 122       --           system handler)
 123
 124       use Interfaces.C;
 125
 126    begin
 127       Abort_Task_Interrupt := Abort_Signal;
 128
 129       pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False));
 130       pragma Assert (Reserve = (Interrupt_ID'Range => False));
 131
 132       --  Process state of exception signals
 133
 134       for J in Exception_Interrupts'Range loop
 135          if State (Exception_Interrupts (J)) /= User then
 136             Keep_Unmasked (Exception_Interrupts (J)) := True;
 137             Reserve (Exception_Interrupts (J)) := True;
 138          end if;
 139       end loop;
 140
 141       if State (Abort_Task_Interrupt) /= User then
 142          Keep_Unmasked (Abort_Task_Interrupt) := True;
 143          Reserve (Abort_Task_Interrupt) := True;
 144       end if;
 145
 146       --  Set SIGINT to unmasked state as long as it's
 147       --  not in "User" state.  Check for Unreserve_All_Interrupts last
 148
 149       if State (SIGINT) /= User then
 150          Keep_Unmasked (SIGINT) := True;
 151       end if;
 152
 153       --  Check all signals for state that requires keeping them
 154       --  unmasked and reserved
 155
 156       for J in Interrupt_ID'Range loop
 157          if State (J) = Default or else State (J) = Runtime then
 158             Keep_Unmasked (J) := True;
 159             Reserve (J) := True;
 160          end if;
 161       end loop;
 162
 163       --  Add target-specific reserved signals
 164
 165       for J in Reserved_Interrupts'Range loop
 166          Reserve (Interrupt_ID (Reserved_Interrupts (J))) := True;
 167       end loop;
 168
 169       --  Process pragma Unreserve_All_Interrupts. This overrides any
 170       --  settings due to pragma Interrupt_State:
 171
 172       if Unreserve_All_Interrupts /= 0 then
 173          Keep_Unmasked (SIGINT) := False;
 174          Reserve (SIGINT) := False;
 175       end if;
 176
 177       --  We do not have Signal 0 in reality. We just use this value
 178       --  to identify not existing signals (see s-intnam.ads). Therefore,
 179       --  Signal 0 should not be used in all signal related operations hence
 180       --  mark it as reserved.
 181
 182       Reserve (0) := True;
 183    end;
 184 end System.Interrupt_Management;