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------------------------------------------------------------------------------
--                                                                          --
--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
--                                                                          --
--                   S Y S T E M . O S _ I N T E R F A C E                  --
--                                                                          --
--                                  B o d y                                 --
--                                                                          --
--          Copyright (C) 1997-2009, Free Software Foundation, Inc.         --
--                                                                          --
-- GNARL is free software; you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNARL was developed by the GNARL team at Florida State University.       --
-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
--                                                                          --
------------------------------------------------------------------------------
 
--  This is a AIX (Native) version of this package
 
pragma Polling (Off);
--  Turn off polling, we do not want ATC polling to take place during tasking
--  operations. It causes infinite loops and other problems.
 
package body System.OS_Interface is
 
   use Interfaces.C;
 
   -----------------
   -- To_Duration --
   -----------------
 
   function To_Duration (TS : timespec) return Duration is
   begin
      return Duration (TS.tv_sec) + Duration (TS.tv_nsec) / 10#1#E9;
   end To_Duration;
 
   ------------------------
   -- To_Target_Priority --
   ------------------------
 
   function To_Target_Priority
     (Prio : System.Any_Priority) return Interfaces.C.int
   is
      Dispatching_Policy : Character;
      pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 
      Time_Slice_Val : Integer;
      pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 
   begin
      --  For the case SCHED_OTHER the only valid priority across all supported
      --  versions of AIX is 1 (note that the scheduling policy can be set
      --  with the pragma Task_Dispatching_Policy or setting the time slice
      --  value). Otherwise, for SCHED_RR and SCHED_FIFO, the system defines
      --  priorities in the range 1 .. 127. This means that we must map
      --  System.Any_Priority in the range 0 .. 126 to 1 .. 127.
 
      if Dispatching_Policy = ' ' and then Time_Slice_Val < 0 then
         return 1;
      else
         return Interfaces.C.int (Prio) + 1;
      end if;
   end To_Target_Priority;
 
   -----------------
   -- To_Timespec --
   -----------------
 
   function To_Timespec (D : Duration) return timespec is
      S : time_t;
      F : Duration;
 
   begin
      S := time_t (Long_Long_Integer (D));
      F := D - Duration (S);
 
      --  If F is negative due to a round-up, adjust for positive F value
 
      if F < 0.0 then
         S := S - 1;
         F := F + 1.0;
      end if;
 
      return timespec'(tv_sec => S,
                       tv_nsec => long (Long_Long_Integer (F * 10#1#E9)));
   end To_Timespec;
 
   -------------------
   -- clock_gettime --
   -------------------
 
   function clock_gettime
     (clock_id : clockid_t;
      tp       : access timespec)
      return     int
   is
      pragma Unreferenced (clock_id);
 
      --  Older AIX don't have clock_gettime, so use gettimeofday
 
      use Interfaces;
 
      type timeval is array (1 .. 2) of C.long;
 
      procedure timeval_to_duration
        (T    : not null access timeval;
         sec  : not null access C.long;
         usec : not null access C.long);
      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
 
      Micro  : constant := 10**6;
      sec    : aliased C.long;
      usec   : aliased C.long;
      TV     : aliased timeval;
      Result : int;
 
      function gettimeofday
        (Tv : access timeval;
         Tz : System.Address := System.Null_Address) return int;
      pragma Import (C, gettimeofday, "gettimeofday");
 
   begin
      Result := gettimeofday (TV'Access, System.Null_Address);
      pragma Assert (Result = 0);
      timeval_to_duration (TV'Access, sec'Access, usec'Access);
      tp.all := To_Timespec (Duration (sec) + Duration (usec) / Micro);
      return Result;
   end clock_gettime;
 
   -----------------
   -- sched_yield --
   -----------------
 
   --  AIX Thread does not have sched_yield;
 
   function sched_yield return int is
      procedure pthread_yield;
      pragma Import (C, pthread_yield, "sched_yield");
   begin
      pthread_yield;
      return 0;
   end sched_yield;
 
   --------------------
   -- Get_Stack_Base --
   --------------------
 
   function Get_Stack_Base (thread : pthread_t) return Address is
      pragma Warnings (Off, thread);
   begin
      return Null_Address;
   end Get_Stack_Base;
 
   --------------------------
   -- PTHREAD_PRIO_INHERIT --
   --------------------------
 
   AIX_Version : Integer := 0;
   --  AIX version in the form xy for AIX version x.y (0 means not set)
 
   SYS_NMLN : constant := 32;
   --  AIX system constant used to define utsname, see sys/utsname.h
 
   subtype String_NMLN is String (1 .. SYS_NMLN);
 
   type utsname is record
      sysname    : String_NMLN;
      nodename   : String_NMLN;
      release    : String_NMLN;
      version    : String_NMLN;
      machine    : String_NMLN;
      procserial : String_NMLN;
   end record;
   pragma Convention (C, utsname);
 
   procedure uname (name : out utsname);
   pragma Import (C, uname);
 
   function PTHREAD_PRIO_INHERIT return int is
      name : utsname;
 
      function Val (C : Character) return Integer;
      --  Transform a numeric character ('0' .. '9') to an integer
 
      ---------
      -- Val --
      ---------
 
      function Val (C : Character) return Integer is
      begin
         return Character'Pos (C) - Character'Pos ('0');
      end Val;
 
   --  Start of processing for PTHREAD_PRIO_INHERIT
 
   begin
      if AIX_Version = 0 then
 
         --  Set AIX_Version
 
         uname (name);
         AIX_Version := Val (name.version (1)) * 10 + Val (name.release (1));
      end if;
 
      if AIX_Version < 53 then
 
         --  Under AIX < 5.3, PTHREAD_PRIO_INHERIT is defined as 0 in pthread.h
 
         return 0;
 
      else
         --  Under AIX >= 5.3, PTHREAD_PRIO_INHERIT is defined as 3
 
         return 3;
      end if;
   end PTHREAD_PRIO_INHERIT;
 
end System.OS_Interface;