-- --
-- B o d y --
-- --
--- Copyright (C) 1999-2006 Free Software Foundation, Inc. --
+-- Copyright (C) 1999-2006, 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- --
package body System.Stack_Checking.Operations is
- -- In order to have stack checking working appropriately on
- -- VxWorks we need to extract the stack size information from the
- -- VxWorks kernel itself. It means that the library for showing
- -- task-related information needs to be linked into the VxWorks
- -- system, when using stack checking. The TaskShow library can be
- -- linked into the VxWorks system by either:
+ -- In order to have stack checking working appropriately on VxWorks we need
+ -- to extract the stack size information from the VxWorks kernel itself. It
+ -- means that the library for showing task-related information needs to be
+ -- linked into the VxWorks system, when using stack checking. The TaskShow
+ -- library can be linked into the VxWorks system by either:
+
-- * defining INCLUDE_SHOW_ROUTINES in config.h when using
-- configuration header files, or
+
-- * selecting INCLUDE_TASK_SHOW when using the Tornado project
-- facility.
- function Set_Stack_Info (Stack : access Stack_Access) return Stack_Access;
+ function Set_Stack_Info
+ (Stack : not null access Stack_Access) return Stack_Access;
- -- The function Set_Stack_Info is the actual function that updates
- -- the cache containing a pointer to the Stack_Info. It may also
- -- be used for detecting asynchronous abort in combination with
- -- Invalidate_Self_Cache.
+ -- The function Set_Stack_Info is the actual function that updates the
+ -- cache containing a pointer to the Stack_Info. It may also be used for
+ -- detecting asynchronous abort in combination with Invalidate_Self_Cache.
-- Set_Stack_Info should do the following things in order:
-- 1) Get the Stack_Access value for the current task
-- 2) Set Stack.all to the value obtained in 1)
-- 3) Optionally Poll to check for asynchronous abort
- -- This order is important because if at any time a write to
- -- the stack cache is pending, that write should be followed
- -- by a Poll to prevent loosing signals.
+ -- This order is important because if at any time a write to the stack
+ -- cache is pending, that write should be followed by a Poll to prevent
+ -- loosing signals.
-- Note: This function must be compiled with Polling turned off
-- Note: on systems like VxWorks and OS/2 with real thread-local storage,
-- Set_Stack_Info should return an access value for such local
-- storage. In those cases the cache will always be up-to-date.
+ -- Fix examples??? Linux???
-- The following constants should be imported from some system-specific
-- constants package. The constants must be static for performance reasons.
--------------------
function Set_Stack_Info
- (Stack : access Stack_Access) return Stack_Access
+ (Stack : not null access Stack_Access) return Stack_Access
is
-
-- Task descriptor that is handled internally by the VxWorks kernel
type Td_Events_Storage is array (1 .. 4) of Interfaces.C.int;
-- This VxWorks procedure fills in a specified task descriptor
-- for a specified task.
- procedure TaskInfoGet (T_Id : System.OS_Interface.t_id;
- Task_Desc : access Task_Descriptor);
+ procedure TaskInfoGet
+ (T_Id : System.OS_Interface.t_id;
+ Task_Desc : not null access Task_Descriptor);
pragma Import (C, TaskInfoGet, "taskInfoGet");
My_Stack : Stack_Access;
if My_Stack.Base = Null_Address then
- -- First invocation. Ask the VxWorks kernel about stack
- -- values.
+ -- First invocation. Ask the VxWorks kernel about stack values
+
TaskInfoGet (System.OS_Interface.taskIdSelf, Task_Desc'Access);
- My_Stack.Size := System.Storage_Elements.Storage_Offset
- (Task_Desc.Td_StackSize);
+ My_Stack.Size :=
+ System.Storage_Elements.Storage_Offset (Task_Desc.Td_StackSize);
My_Stack.Base := Task_Desc.Td_PStackBase;
My_Stack.Limit := Task_Desc.Td_PStackLimit;
raise Standard'Abort_Signal;
end if;
- return My_Stack; -- Never trust the cached value, but return local copy!
+ -- Never trust the cached value, return local copy!
+
+ return My_Stack;
end Set_Stack_Info;
-----------------
(Stack_Address : System.Address) return Stack_Access
is
type Frame_Marker is null record;
+
Marker : Frame_Marker;
Cached_Stack : constant Stack_Access := Cache;
Frame_Address : constant System.Address := Marker'Address;
begin
- -- This function first does a "cheap" check which is correct
- -- if it succeeds. In case of failure, the full check is done.
- -- Ideally the cheap check should be done in an optimized manner,
- -- or be inlined.
-
- if (Stack_Grows_Down and then
- (Frame_Address <= Cached_Stack.Base
- and
- Stack_Address > Cached_Stack.Limit))
- or else
- (not Stack_Grows_Down and then
- (Frame_Address >= Cached_Stack.Base
- and
- Stack_Address < Cached_Stack.Limit))
+ -- The parameter may have wrapped around in System.Address arithmetics.
+ -- In that case, we have no other choices than raising the exception.
+
+ if (Stack_Grows_Down and then Stack_Address > Frame_Address)
+ or else (not Stack_Grows_Down and then Stack_Address < Frame_Address)
+ then
+ Ada.Exceptions.Raise_Exception
+ (E => Storage_Error'Identity,
+ Message => "stack overflow detected");
+ end if;
+
+ -- This function first does a "cheap" check which is correct if it
+ -- succeeds. In case of failure, the full check is done. Ideally the
+ -- cheap check should be done in an optimized manner, or be inlined.
+
+ if (Stack_Grows_Down
+ and then Frame_Address <= Cached_Stack.Base
+ and then Stack_Address > Cached_Stack.Limit)
+ or else (not Stack_Grows_Down
+ and then Frame_Address >= Cached_Stack.Base
+ and then Stack_Address < Cached_Stack.Limit)
then
-- Cached_Stack is valid as it passed the stack check
+
return Cached_Stack;
end if;
Full_Check :
declare
My_Stack : constant Stack_Access := Set_Stack_Info (Cache'Access);
- -- At this point Stack.all might already be invalid, so
- -- it is essential to use our local copy of Stack!
+ -- At this point Stack.all might already be invalid, so it is
+ -- essential to use our local copy of Stack!
begin
- if (Stack_Grows_Down and then
- Stack_Address < My_Stack.Limit)
- or else
- (not Stack_Grows_Down and then
- Stack_Address > My_Stack.Limit)
+ if (Stack_Grows_Down
+ and then Stack_Address < My_Stack.Limit)
+ or else (not Stack_Grows_Down
+ and then Stack_Address > My_Stack.Limit)
then
Ada.Exceptions.Raise_Exception
(E => Storage_Error'Identity,
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