gcc/ada/s-interr.ads

   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 S                    --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005 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- --
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  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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, 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 --  Note: the compiler generates direct calls to this interface, via Rtsfind.
  35 --  Any changes to this interface may require corresponding compiler changes.
  36
  37 --  This package encapsulates the implementation of interrupt or signal
  38 --  handlers.  It is logically an extension of the body of Ada.Interrupts.
  39 --  It is made a child of System to allow visibility of various
  40 --  runtime system internal data and operations.
  41
  42 --  See System.Interrupt_Management for core interrupt/signal interfaces
  43
  44 --  These two packages are separated in order to allow
  45 --  System.Interrupt_Management to be used without requiring the whole
  46 --  tasking implementation to be linked and elaborated.
  47
  48 with System.Tasking;
  49 --  used for Task_Id
  50
  51 with System.Tasking.Protected_Objects.Entries;
  52 --  used for Protection_Entries
  53
  54 with System.OS_Interface;
  55 --  used for Max_Interrupt
  56
  57 package System.Interrupts is
  58
  59    pragma Elaborate_Body;
  60    --  Comment needed on why this is here ???
  61
  62    -------------------------
  63    -- Constants and types --
  64    -------------------------
  65
  66    Default_Interrupt_Priority : constant System.Interrupt_Priority :=
  67      System.Interrupt_Priority'Last;
  68    --  Default value used when a pragma Interrupt_Handler or Attach_Handler is
  69    --  specified without an Interrupt_Priority pragma, see D.3(10).
  70
  71    type Ada_Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
  72    --  Avoid inheritance by Ada.Interrupts.Interrupt_ID of unwanted operations
  73
  74    type Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
  75
  76    --  The following renaming is introduced so that the type is accessible
  77    --  through rtsfind, otherwise the name clashes with its homonym in
  78    --  ada.interrupts.
  79
  80    subtype System_Interrupt_Id is Interrupt_ID;
  81
  82    type Parameterless_Handler is access protected procedure;
  83
  84    ----------------------
  85    -- General services --
  86    ----------------------
  87
  88    --  Attempt to attach a Handler to an Interrupt to which an Entry is
  89    --  already bound will raise a Program_Error.
  90
  91    function Is_Reserved (Interrupt : Interrupt_ID) return Boolean;
  92
  93    function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean;
  94
  95    function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean;
  96
  97    function Current_Handler
  98      (Interrupt : Interrupt_ID) return Parameterless_Handler;
  99
 100    --  Calling the following procedures with New_Handler = null
 101    --  and Static = true means that we want to modify the current handler
 102    --  regardless of the previous handler's binding status.
 103    --  (i.e. we do not care whether it is a dynamic or static handler)
 104
 105    procedure Attach_Handler
 106      (New_Handler : Parameterless_Handler;
 107       Interrupt   : Interrupt_ID;
 108       Static      : Boolean := False);
 109
 110    procedure Exchange_Handler
 111      (Old_Handler : out Parameterless_Handler;
 112       New_Handler : Parameterless_Handler;
 113       Interrupt   : Interrupt_ID;
 114       Static      : Boolean := False);
 115
 116    procedure Detach_Handler
 117      (Interrupt : Interrupt_ID;
 118       Static    : Boolean := False);
 119
 120    function Reference
 121      (Interrupt : Interrupt_ID) return System.Address;
 122
 123    --------------------------------
 124    -- Interrupt Entries Services --
 125    --------------------------------
 126
 127    --  Routines needed for Interrupt Entries
 128
 129    procedure Bind_Interrupt_To_Entry
 130      (T       : System.Tasking.Task_Id;
 131       E       : System.Tasking.Task_Entry_Index;
 132       Int_Ref : System.Address);
 133    --  Bind the given interrupt to the given entry. If the interrupt is
 134    --  already bound to another entry, Program_Error will be raised.
 135
 136    procedure Detach_Interrupt_Entries (T : System.Tasking.Task_Id);
 137    --  This procedure detaches all the Interrupt Entries bound to a task.
 138
 139    ------------------------------
 140    -- POSIX.5 Signals Services --
 141    ------------------------------
 142
 143    --  Routines needed for POSIX dot5 POSIX_Signals
 144
 145    procedure Block_Interrupt (Interrupt : Interrupt_ID);
 146    --  Block the Interrupt on the process level
 147
 148    procedure Unblock_Interrupt (Interrupt : Interrupt_ID);
 149
 150    function Unblocked_By
 151      (Interrupt : Interrupt_ID) return System.Tasking.Task_Id;
 152    --  It returns the ID of the last Task which Unblocked this Interrupt.
 153    --  It returns Null_Task if no tasks have ever requested the
 154    --  Unblocking operation or the Interrupt is currently Blocked.
 155
 156    function Is_Blocked (Interrupt : Interrupt_ID) return Boolean;
 157    --  Comment needed ???
 158
 159    procedure Ignore_Interrupt (Interrupt : Interrupt_ID);
 160    --  Set the sigacion for the interrupt to SIG_IGN.
 161
 162    procedure Unignore_Interrupt (Interrupt : Interrupt_ID);
 163    --  Comment needed ???
 164
 165    function Is_Ignored (Interrupt : Interrupt_ID) return Boolean;
 166    --  Comment needed ???
 167
 168    --  Note : Direct calls to sigaction, sigprocmask, thr_sigsetmask or any
 169    --  other low-level interface that changes the signal action or signal mask
 170    --  needs a careful thought.
 171
 172    --  One may acheive the effect of system calls first making RTS blocked
 173    --  (by calling Block_Interrupt) for the signal under consideration.
 174    --  This will make all the tasks in RTS blocked for the Interrupt.
 175
 176    ----------------------
 177    -- Protection Types --
 178    ----------------------
 179
 180    --  Routines and types needed to implement Interrupt_Handler and
 181    --  Attach_Handler.
 182
 183    --  There are two kinds of protected objects that deal with interrupts:
 184
 185    --  (1) Only Interrupt_Handler pragmas are used. We need to be able to tell
 186    --  if an Interrupt_Handler applies to a given procedure, so
 187    --  Register_Interrupt_Handler has to be called for all the potential
 188    --  handlers, it should be done by calling Register_Interrupt_Handler with
 189    --  the handler code address. On finalization, which can happen only has
 190    --  part of library level finalization since PO with Interrupt_Handler
 191    --  pragmas can only be declared at library level, nothing special needs to
 192    --  be done since the default handlers have been restored as part of task
 193    --  completion which is done just before global finalization.
 194    --  Dynamic_Interrupt_Protection should be used in this case.
 195
 196    --  (2) Attach_Handler pragmas are used, and possibly Interrupt_Handler
 197    --  pragma. We need to attach the handlers to the given interrupts when the
 198    --  objet is elaborated. This should be done by constructing an array of
 199    --  pairs (interrupt, handler) from the pragmas and calling Install_Handlers
 200    --  with it (types to be used are New_Handler_Item and New_Handler_Array).
 201    --  On finalization, we need to restore the handlers that were installed
 202    --  before the elaboration of the PO, so we need to store these previous
 203    --  handlers. This is also done by Install_Handlers, the room for these
 204    --  informations is provided by adding a discriminant which is the number
 205    --  of Attach_Handler pragmas and an array of this size in the protection
 206    --  type, Static_Interrupt_Protection.
 207
 208    procedure Register_Interrupt_Handler
 209      (Handler_Addr : System.Address);
 210    --  This routine should be called by the compiler to allow the handler be
 211    --  used as an Interrupt Handler. That means call this procedure for each
 212    --  pragma Interrup_Handler providing the address of the handler (not
 213    --  including the pointer to the actual PO, this way this routine is called
 214    --  only once for each type definition of PO).
 215
 216    type Static_Handler_Index is range 0 .. Integer'Last;
 217    subtype Positive_Static_Handler_Index is
 218      Static_Handler_Index range 1 .. Static_Handler_Index'Last;
 219    --  Comment needed ???
 220
 221    type Previous_Handler_Item is record
 222       Interrupt : Interrupt_ID;
 223       Handler   : Parameterless_Handler;
 224       Static    : Boolean;
 225    end record;
 226    --  Contains all the information needed to restore a previous handler
 227
 228    type Previous_Handler_Array is array
 229      (Positive_Static_Handler_Index range <>) of Previous_Handler_Item;
 230
 231    type New_Handler_Item is record
 232       Interrupt : Interrupt_ID;
 233       Handler   : Parameterless_Handler;
 234    end record;
 235    --  Contains all the information from an Attach_Handler pragma
 236
 237    type New_Handler_Array is
 238      array (Positive_Static_Handler_Index range <>) of New_Handler_Item;
 239    --  Comment needed ???
 240
 241    --  Case (1)
 242
 243    type Dynamic_Interrupt_Protection is new
 244      Tasking.Protected_Objects.Entries.Protection_Entries with null record;
 245
 246    --  ??? Finalize is not overloaded since we currently have no
 247    --  way to detach the handlers during library level finalization.
 248
 249    function Has_Interrupt_Or_Attach_Handler
 250      (Object : access Dynamic_Interrupt_Protection) return Boolean;
 251    --  Returns True
 252
 253    --  Case (2)
 254
 255    type Static_Interrupt_Protection
 256      (Num_Entries        : Tasking.Protected_Objects.Protected_Entry_Index;
 257       Num_Attach_Handler : Static_Handler_Index)
 258    is new
 259      Tasking.Protected_Objects.Entries.Protection_Entries (Num_Entries) with
 260      record
 261        Previous_Handlers : Previous_Handler_Array (1 .. Num_Attach_Handler);
 262      end record;
 263
 264    function Has_Interrupt_Or_Attach_Handler
 265      (Object : access Static_Interrupt_Protection) return Boolean;
 266    --  Returns True
 267
 268    procedure Finalize (Object : in out Static_Interrupt_Protection);
 269    --  Restore previous handlers as required by C.3.1(12) then call
 270    --  Finalize (Protection).
 271
 272    procedure Install_Handlers
 273      (Object       : access Static_Interrupt_Protection;
 274       New_Handlers : New_Handler_Array);
 275    --  Store the old handlers in Object.Previous_Handlers and install
 276    --  the new static handlers.
 277
 278 end System.Interrupts;