File : posix-memory_range_locking.adb


------------------------------------------------------------------------------
--                                                                          --
--            FLORIST (FSU Implementation of POSIX.5) COMPONENTS            --
--                                                                          --
--            P O S I X . M E M O R Y _ R A N G E _ L O C K I N G           --
--                                                                          --
--                                  B o d y                                 --
--                                                                          --
--                                                                          --
--  Copyright (c) 1996-1998                 Florida State University (FSU)  --
--  All Rights Reserved.                                                    --
--                                                                          --
--  This file is a component of FLORIST, an  implementation of an  Ada API  --
--  for the POSIX OS services, for use with  the  GNAT  Ada  compiler  and  --
--  the FSU Gnu Ada Runtime Library (GNARL).   The  interface  is intended  --
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--  1003.5b: 1996.                                                          --
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--  FLORIST is free software;  you can  redistribute  it and/or  modify it  --
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------------------------------------------------------------------------------
--  [$Revision: 1.1.1.1 $]

with POSIX.C,
     POSIX.Implementation;
package body POSIX.Memory_Range_Locking is

   use POSIX.C,
       POSIX.Implementation;

   ------------------
   --  Lock_Range  --
   ------------------

   procedure Lock_Range
     (First  : in System.Address;
      Length : in System.Storage_Elements.Storage_Offset) is
      function mlock (addr : access System.Address; len : size_t) return int;
      pragma Import (C, mlock, mlock_LINKNAME);
      Addr : aliased System.Address := First;
   begin
      --  .... Some OS (eg. Solaris) has non-standard mlock/munlock.
      --  For the reason if "mlock/munlock" fails with EINVAL,
      --  we speculate that the OS has non-standard form of the
      --  functions. So, try it again with a different form of the function.

      --  .... This is not a perfact solution and we feel that this kind of
      --  thing has to be resolved in the configuration management. It does its
      --  work for now....

      if (mlock (Addr'Unchecked_Access, size_t (Length)) = -1) and then
        (Fetch_Errno = Invalid_Argument) then
         declare
            function mlock (addr : System.Address; len : size_t) return int;
            pragma Import (C, mlock, mlock_LINKNAME);
         begin
            Check (mlock (Addr, size_t (Length)));
         end;
      else
         Check (mlock (Addr'Unchecked_Access, size_t (Length)));
      end if;
   end Lock_Range;

   --------------------
   --  UnLock_Range  --
   --------------------

   procedure Unlock_Range
     (First  : in System.Address;
      Length : in System.Storage_Elements.Storage_Offset) is
      function munlock (addr : access System.Address; len : size_t) return int;
      pragma Import (C, munlock, munlock_LINKNAME);
      Addr : aliased System.Address := First;
   begin
      if (munlock (Addr'Unchecked_Access, size_t (Length)) = -1) and then
        (Fetch_Errno = Invalid_Argument) then
         declare
            function munlock (addr : System.Address; len : size_t) return int;
            pragma Import (C, munlock, munlock_LINKNAME);
         begin
            Check (munlock (Addr, size_t (Length)));
         end;
      else
         Check (munlock (Addr'Unchecked_Access, size_t (Length)));
      end if;
   end Unlock_Range;

end POSIX.Memory_Range_Locking;