| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- |
| -- -- |
| -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2003, 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 2, or (at your option) any later ver- -- |
| -- sion. GNARL 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. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNARL; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- |
| -- MA 02111-1307, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- unit, or you link this unit with other files to produce an executable, -- |
| -- this unit does not by itself cause the resulting executable to be -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- GNARL was developed by the GNARL team at Florida State University. -- |
| -- Extensive contributions were provided by Ada Core Technologies, Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This is a NT (native) version of this package |
| |
| -- This package contains all the GNULL primitives that interface directly |
| -- with the underlying OS. |
| |
| 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. |
| |
| with System.Tasking.Debug; |
| -- used for Known_Tasks |
| |
| with Interfaces.C; |
| -- used for int |
| -- size_t |
| |
| with Interfaces.C.Strings; |
| -- used for Null_Ptr |
| |
| with System.OS_Interface; |
| -- used for various type, constant, and operations |
| |
| with System.Parameters; |
| -- used for Size_Type |
| |
| with System.Tasking; |
| -- used for Ada_Task_Control_Block |
| -- Task_ID |
| |
| with System.Soft_Links; |
| -- used for Defer/Undefer_Abort |
| -- to initialize TSD for a C thread, in function Self |
| |
| -- Note that we do not use System.Tasking.Initialization directly since |
| -- this is a higher level package that we shouldn't depend on. For example |
| -- when using the restricted run time, it is replaced by |
| -- System.Tasking.Restricted.Initialization |
| |
| with System.OS_Primitives; |
| -- used for Delay_Modes |
| |
| with System.Task_Info; |
| -- used for Unspecified_Task_Info |
| |
| with Unchecked_Conversion; |
| with Unchecked_Deallocation; |
| |
| package body System.Task_Primitives.Operations is |
| |
| use System.Tasking.Debug; |
| use System.Tasking; |
| use Interfaces.C; |
| use Interfaces.C.Strings; |
| use System.OS_Interface; |
| use System.Parameters; |
| use System.OS_Primitives; |
| |
| pragma Link_With ("-Xlinker --stack=0x800000,0x1000"); |
| -- Change the stack size (8 MB) for tasking programs on Windows. This |
| -- permit to have more than 30 tasks running at the same time. Note that |
| -- we set the stack size for non tasking programs on System unit. |
| |
| package SSL renames System.Soft_Links; |
| |
| ---------------- |
| -- Local Data -- |
| ---------------- |
| |
| Environment_Task_ID : Task_ID; |
| -- A variable to hold Task_ID for the environment task. |
| |
| Single_RTS_Lock : aliased RTS_Lock; |
| -- This is a lock to allow only one thread of control in the RTS at |
| -- a time; it is used to execute in mutual exclusion from all other tasks. |
| -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List |
| |
| Time_Slice_Val : Integer; |
| pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); |
| |
| Dispatching_Policy : Character; |
| pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy"); |
| |
| FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F'; |
| -- Indicates whether FIFO_Within_Priorities is set. |
| |
| Foreign_Task_Elaborated : aliased Boolean := True; |
| -- Used to identified fake tasks (i.e., non-Ada Threads). |
| |
| ------------------------------------ |
| -- The thread local storage index -- |
| ------------------------------------ |
| |
| TlsIndex : DWORD; |
| pragma Export (Ada, TlsIndex); |
| -- To ensure that this variable won't be local to this package, since |
| -- in some cases, inlining forces this variable to be global anyway. |
| |
| -------------------- |
| -- Local Packages -- |
| -------------------- |
| |
| package Specific is |
| |
| function Is_Valid_Task return Boolean; |
| pragma Inline (Is_Valid_Task); |
| -- Does executing thread have a TCB? |
| |
| procedure Set (Self_Id : Task_ID); |
| pragma Inline (Set); |
| -- Set the self id for the current task. |
| |
| end Specific; |
| |
| package body Specific is |
| |
| function Is_Valid_Task return Boolean is |
| begin |
| return TlsGetValue (TlsIndex) /= System.Null_Address; |
| end Is_Valid_Task; |
| |
| procedure Set (Self_Id : Task_ID) is |
| Succeeded : BOOL; |
| begin |
| Succeeded := TlsSetValue (TlsIndex, To_Address (Self_Id)); |
| pragma Assert (Succeeded = True); |
| end Set; |
| |
| end Specific; |
| |
| --------------------------------- |
| -- Support for foreign threads -- |
| --------------------------------- |
| |
| function Register_Foreign_Thread (Thread : Thread_Id) return Task_ID; |
| -- Allocate and Initialize a new ATCB for the current Thread. |
| |
| function Register_Foreign_Thread |
| (Thread : Thread_Id) return Task_ID is separate; |
| |
| ---------------------------------- |
| -- Utility Conversion Functions -- |
| ---------------------------------- |
| |
| function To_Task_Id is new Unchecked_Conversion (System.Address, Task_ID); |
| |
| function To_Address is new Unchecked_Conversion (Task_ID, System.Address); |
| |
| ---------------------------------- |
| -- Condition Variable Functions -- |
| ---------------------------------- |
| |
| procedure Initialize_Cond (Cond : access Condition_Variable); |
| -- Initialize given condition variable Cond |
| |
| procedure Finalize_Cond (Cond : access Condition_Variable); |
| -- Finalize given condition variable Cond. |
| |
| procedure Cond_Signal (Cond : access Condition_Variable); |
| -- Signal condition variable Cond |
| |
| procedure Cond_Wait |
| (Cond : access Condition_Variable; |
| L : access RTS_Lock); |
| -- Wait on conditional variable Cond, using lock L |
| |
| procedure Cond_Timed_Wait |
| (Cond : access Condition_Variable; |
| L : access RTS_Lock; |
| Rel_Time : Duration; |
| Timed_Out : out Boolean; |
| Status : out Integer); |
| -- Do timed wait on condition variable Cond using lock L. The duration |
| -- of the timed wait is given by Rel_Time. When the condition is |
| -- signalled, Timed_Out shows whether or not a time out occurred. |
| -- Status is only valid if Timed_Out is False, in which case it |
| -- shows whether Cond_Timed_Wait completed successfully. |
| |
| --------------------- |
| -- Initialize_Cond -- |
| --------------------- |
| |
| procedure Initialize_Cond (Cond : access Condition_Variable) is |
| hEvent : HANDLE; |
| |
| begin |
| hEvent := CreateEvent (null, True, False, Null_Ptr); |
| pragma Assert (hEvent /= 0); |
| Cond.all := Condition_Variable (hEvent); |
| end Initialize_Cond; |
| |
| ------------------- |
| -- Finalize_Cond -- |
| ------------------- |
| |
| -- No such problem here, DosCloseEventSem has been derived. |
| -- What does such refer to in above comment??? |
| |
| procedure Finalize_Cond (Cond : access Condition_Variable) is |
| Result : BOOL; |
| begin |
| Result := CloseHandle (HANDLE (Cond.all)); |
| pragma Assert (Result = True); |
| end Finalize_Cond; |
| |
| ----------------- |
| -- Cond_Signal -- |
| ----------------- |
| |
| procedure Cond_Signal (Cond : access Condition_Variable) is |
| Result : BOOL; |
| begin |
| Result := SetEvent (HANDLE (Cond.all)); |
| pragma Assert (Result = True); |
| end Cond_Signal; |
| |
| --------------- |
| -- Cond_Wait -- |
| --------------- |
| |
| -- Pre-assertion: Cond is posted |
| -- L is locked. |
| |
| -- Post-assertion: Cond is posted |
| -- L is locked. |
| |
| procedure Cond_Wait |
| (Cond : access Condition_Variable; |
| L : access RTS_Lock) |
| is |
| Result : DWORD; |
| Result_Bool : BOOL; |
| |
| begin |
| -- Must reset Cond BEFORE L is unlocked. |
| |
| Result_Bool := ResetEvent (HANDLE (Cond.all)); |
| pragma Assert (Result_Bool = True); |
| Unlock (L); |
| |
| -- No problem if we are interrupted here: if the condition is signaled, |
| -- WaitForSingleObject will simply not block |
| |
| Result := WaitForSingleObject (HANDLE (Cond.all), Wait_Infinite); |
| pragma Assert (Result = 0); |
| |
| Write_Lock (L); |
| end Cond_Wait; |
| |
| --------------------- |
| -- Cond_Timed_Wait -- |
| --------------------- |
| |
| -- Pre-assertion: Cond is posted |
| -- L is locked. |
| |
| -- Post-assertion: Cond is posted |
| -- L is locked. |
| |
| procedure Cond_Timed_Wait |
| (Cond : access Condition_Variable; |
| L : access RTS_Lock; |
| Rel_Time : Duration; |
| Timed_Out : out Boolean; |
| Status : out Integer) |
| is |
| Time_Out_Max : constant DWORD := 16#FFFF0000#; |
| -- NT 4 cannot handle timeout values that are too large, |
| -- e.g. DWORD'Last - 1 |
| |
| Time_Out : DWORD; |
| Result : BOOL; |
| Wait_Result : DWORD; |
| |
| begin |
| -- Must reset Cond BEFORE L is unlocked. |
| |
| Result := ResetEvent (HANDLE (Cond.all)); |
| pragma Assert (Result = True); |
| Unlock (L); |
| |
| -- No problem if we are interrupted here: if the condition is signaled, |
| -- WaitForSingleObject will simply not block |
| |
| if Rel_Time <= 0.0 then |
| Timed_Out := True; |
| Wait_Result := 0; |
| |
| else |
| if Rel_Time >= Duration (Time_Out_Max) / 1000 then |
| Time_Out := Time_Out_Max; |
| else |
| Time_Out := DWORD (Rel_Time * 1000); |
| end if; |
| |
| Wait_Result := WaitForSingleObject (HANDLE (Cond.all), Time_Out); |
| |
| if Wait_Result = WAIT_TIMEOUT then |
| Timed_Out := True; |
| Wait_Result := 0; |
| else |
| Timed_Out := False; |
| end if; |
| end if; |
| |
| Write_Lock (L); |
| |
| -- Ensure post-condition |
| |
| if Timed_Out then |
| Result := SetEvent (HANDLE (Cond.all)); |
| pragma Assert (Result = True); |
| end if; |
| |
| Status := Integer (Wait_Result); |
| end Cond_Timed_Wait; |
| |
| ------------------ |
| -- Stack_Guard -- |
| ------------------ |
| |
| -- The underlying thread system sets a guard page at the |
| -- bottom of a thread stack, so nothing is needed. |
| -- ??? Check the comment above |
| |
| procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is |
| pragma Warnings (Off, T); |
| pragma Warnings (Off, On); |
| |
| begin |
| null; |
| end Stack_Guard; |
| |
| -------------------- |
| -- Get_Thread_Id -- |
| -------------------- |
| |
| function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is |
| begin |
| return T.Common.LL.Thread; |
| end Get_Thread_Id; |
| |
| ---------- |
| -- Self -- |
| ---------- |
| |
| function Self return Task_ID is |
| Self_Id : constant Task_ID := To_Task_Id (TlsGetValue (TlsIndex)); |
| |
| begin |
| if Self_Id = null then |
| return Register_Foreign_Thread (GetCurrentThread); |
| else |
| return Self_Id; |
| end if; |
| end Self; |
| |
| --------------------- |
| -- Initialize_Lock -- |
| --------------------- |
| |
| -- Note: mutexes and cond_variables needed per-task basis are |
| -- initialized in Intialize_TCB and the Storage_Error is handled. |
| -- Other mutexes (such as RTS_Lock, Memory_Lock...) used in |
| -- the RTS is initialized before any status change of RTS. |
| -- Therefore raising Storage_Error in the following routines |
| -- should be able to be handled safely. |
| |
| procedure Initialize_Lock |
| (Prio : System.Any_Priority; |
| L : access Lock) |
| is |
| begin |
| InitializeCriticalSection (L.Mutex'Access); |
| L.Owner_Priority := 0; |
| L.Priority := Prio; |
| end Initialize_Lock; |
| |
| procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is |
| pragma Unreferenced (Level); |
| |
| begin |
| InitializeCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access); |
| end Initialize_Lock; |
| |
| ------------------- |
| -- Finalize_Lock -- |
| ------------------- |
| |
| procedure Finalize_Lock (L : access Lock) is |
| begin |
| DeleteCriticalSection (L.Mutex'Access); |
| end Finalize_Lock; |
| |
| procedure Finalize_Lock (L : access RTS_Lock) is |
| begin |
| DeleteCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access); |
| end Finalize_Lock; |
| |
| ---------------- |
| -- Write_Lock -- |
| ---------------- |
| |
| procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is |
| begin |
| L.Owner_Priority := Get_Priority (Self); |
| |
| if L.Priority < L.Owner_Priority then |
| Ceiling_Violation := True; |
| return; |
| end if; |
| |
| EnterCriticalSection (L.Mutex'Access); |
| |
| Ceiling_Violation := False; |
| end Write_Lock; |
| |
| procedure Write_Lock |
| (L : access RTS_Lock; |
| Global_Lock : Boolean := False) |
| is |
| begin |
| if not Single_Lock or else Global_Lock then |
| EnterCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access); |
| end if; |
| end Write_Lock; |
| |
| procedure Write_Lock (T : Task_ID) is |
| begin |
| if not Single_Lock then |
| EnterCriticalSection |
| (CRITICAL_SECTION (T.Common.LL.L)'Unrestricted_Access); |
| end if; |
| end Write_Lock; |
| |
| --------------- |
| -- Read_Lock -- |
| --------------- |
| |
| procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is |
| begin |
| Write_Lock (L, Ceiling_Violation); |
| end Read_Lock; |
| |
| ------------ |
| -- Unlock -- |
| ------------ |
| |
| procedure Unlock (L : access Lock) is |
| begin |
| LeaveCriticalSection (L.Mutex'Access); |
| end Unlock; |
| |
| procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is |
| begin |
| if not Single_Lock or else Global_Lock then |
| LeaveCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access); |
| end if; |
| end Unlock; |
| |
| procedure Unlock (T : Task_ID) is |
| begin |
| if not Single_Lock then |
| LeaveCriticalSection |
| (CRITICAL_SECTION (T.Common.LL.L)'Unrestricted_Access); |
| end if; |
| end Unlock; |
| |
| ----------- |
| -- Sleep -- |
| ----------- |
| |
| procedure Sleep |
| (Self_ID : Task_ID; |
| Reason : System.Tasking.Task_States) |
| is |
| pragma Unreferenced (Reason); |
| |
| begin |
| pragma Assert (Self_ID = Self); |
| |
| if Single_Lock then |
| Cond_Wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access); |
| else |
| Cond_Wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access); |
| end if; |
| |
| if Self_ID.Deferral_Level = 0 |
| and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level |
| then |
| Unlock (Self_ID); |
| raise Standard'Abort_Signal; |
| end if; |
| end Sleep; |
| |
| ----------------- |
| -- Timed_Sleep -- |
| ----------------- |
| |
| -- This is for use within the run-time system, so abort is |
| -- assumed to be already deferred, and the caller should be |
| -- holding its own ATCB lock. |
| |
| procedure Timed_Sleep |
| (Self_ID : Task_ID; |
| Time : Duration; |
| Mode : ST.Delay_Modes; |
| Reason : System.Tasking.Task_States; |
| Timedout : out Boolean; |
| Yielded : out Boolean) |
| is |
| pragma Unreferenced (Reason); |
| Check_Time : Duration := Monotonic_Clock; |
| Rel_Time : Duration; |
| Abs_Time : Duration; |
| Result : Integer; |
| |
| Local_Timedout : Boolean; |
| |
| begin |
| Timedout := True; |
| Yielded := False; |
| |
| if Mode = Relative then |
| Rel_Time := Time; |
| Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time; |
| else |
| Rel_Time := Time - Check_Time; |
| Abs_Time := Time; |
| end if; |
| |
| if Rel_Time > 0.0 then |
| loop |
| exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level |
| or else Self_ID.Pending_Priority_Change; |
| |
| if Single_Lock then |
| Cond_Timed_Wait (Self_ID.Common.LL.CV'Access, |
| Single_RTS_Lock'Access, Rel_Time, Local_Timedout, Result); |
| else |
| Cond_Timed_Wait (Self_ID.Common.LL.CV'Access, |
| Self_ID.Common.LL.L'Access, Rel_Time, Local_Timedout, Result); |
| end if; |
| |
| Check_Time := Monotonic_Clock; |
| exit when Abs_Time <= Check_Time; |
| |
| if not Local_Timedout then |
| |
| -- Somebody may have called Wakeup for us |
| |
| Timedout := False; |
| exit; |
| end if; |
| |
| Rel_Time := Abs_Time - Check_Time; |
| end loop; |
| end if; |
| end Timed_Sleep; |
| |
| ----------------- |
| -- Timed_Delay -- |
| ----------------- |
| |
| procedure Timed_Delay |
| (Self_ID : Task_ID; |
| Time : Duration; |
| Mode : ST.Delay_Modes) |
| is |
| Check_Time : Duration := Monotonic_Clock; |
| Rel_Time : Duration; |
| Abs_Time : Duration; |
| Result : Integer; |
| Timedout : Boolean; |
| |
| begin |
| -- Only the little window between deferring abort and |
| -- locking Self_ID is the reason we need to |
| -- check for pending abort and priority change below! |
| |
| SSL.Abort_Defer.all; |
| |
| if Single_Lock then |
| Lock_RTS; |
| end if; |
| |
| Write_Lock (Self_ID); |
| |
| if Mode = Relative then |
| Rel_Time := Time; |
| Abs_Time := Time + Check_Time; |
| else |
| Rel_Time := Time - Check_Time; |
| Abs_Time := Time; |
| end if; |
| |
| if Rel_Time > 0.0 then |
| Self_ID.Common.State := Delay_Sleep; |
| |
| loop |
| if Self_ID.Pending_Priority_Change then |
| Self_ID.Pending_Priority_Change := False; |
| Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority; |
| Set_Priority (Self_ID, Self_ID.Common.Base_Priority); |
| end if; |
| |
| exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; |
| |
| if Single_Lock then |
| Cond_Timed_Wait (Self_ID.Common.LL.CV'Access, |
| Single_RTS_Lock'Access, Rel_Time, Timedout, Result); |
| else |
| Cond_Timed_Wait (Self_ID.Common.LL.CV'Access, |
| Self_ID.Common.LL.L'Access, Rel_Time, Timedout, Result); |
| end if; |
| |
| Check_Time := Monotonic_Clock; |
| exit when Abs_Time <= Check_Time; |
| |
| Rel_Time := Abs_Time - Check_Time; |
| end loop; |
| |
| Self_ID.Common.State := Runnable; |
| end if; |
| |
| Unlock (Self_ID); |
| |
| if Single_Lock then |
| Unlock_RTS; |
| end if; |
| |
| Yield; |
| SSL.Abort_Undefer.all; |
| end Timed_Delay; |
| |
| ------------ |
| -- Wakeup -- |
| ------------ |
| |
| procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is |
| pragma Unreferenced (Reason); |
| |
| begin |
| Cond_Signal (T.Common.LL.CV'Access); |
| end Wakeup; |
| |
| ----------- |
| -- Yield -- |
| ----------- |
| |
| procedure Yield (Do_Yield : Boolean := True) is |
| begin |
| if Do_Yield then |
| Sleep (0); |
| end if; |
| end Yield; |
| |
| ------------------ |
| -- Set_Priority -- |
| ------------------ |
| |
| type Prio_Array_Type is array (System.Any_Priority) of Integer; |
| pragma Atomic_Components (Prio_Array_Type); |
| |
| Prio_Array : Prio_Array_Type; |
| -- Global array containing the id of the currently running task for |
| -- each priority. |
| -- |
| -- Note: we assume that we are on a single processor with run-til-blocked |
| -- scheduling. |
| |
| procedure Set_Priority |
| (T : Task_ID; |
| Prio : System.Any_Priority; |
| Loss_Of_Inheritance : Boolean := False) |
| is |
| Res : BOOL; |
| Array_Item : Integer; |
| |
| begin |
| Res := SetThreadPriority |
| (T.Common.LL.Thread, Interfaces.C.int (Underlying_Priorities (Prio))); |
| pragma Assert (Res = True); |
| |
| if FIFO_Within_Priorities then |
| |
| -- Annex D requirement [RM D.2.2 par. 9]: |
| -- If the task drops its priority due to the loss of inherited |
| -- priority, it is added at the head of the ready queue for its |
| -- new active priority. |
| |
| if Loss_Of_Inheritance |
| and then Prio < T.Common.Current_Priority |
| then |
| Array_Item := Prio_Array (T.Common.Base_Priority) + 1; |
| Prio_Array (T.Common.Base_Priority) := Array_Item; |
| |
| loop |
| -- Let some processes a chance to arrive |
| |
| Yield; |
| |
| -- Then wait for our turn to proceed |
| |
| exit when Array_Item = Prio_Array (T.Common.Base_Priority) |
| or else Prio_Array (T.Common.Base_Priority) = 1; |
| end loop; |
| |
| Prio_Array (T.Common.Base_Priority) := |
| Prio_Array (T.Common.Base_Priority) - 1; |
| end if; |
| end if; |
| |
| T.Common.Current_Priority := Prio; |
| end Set_Priority; |
| |
| ------------------ |
| -- Get_Priority -- |
| ------------------ |
| |
| function Get_Priority (T : Task_ID) return System.Any_Priority is |
| begin |
| return T.Common.Current_Priority; |
| end Get_Priority; |
| |
| ---------------- |
| -- Enter_Task -- |
| ---------------- |
| |
| -- There were two paths were we needed to call Enter_Task : |
| -- 1) from System.Task_Primitives.Operations.Initialize |
| -- 2) from System.Tasking.Stages.Task_Wrapper |
| -- |
| -- The thread initialisation has to be done only for the first case. |
| -- |
| -- This is because the GetCurrentThread NT call does not return the |
| -- real thread handler but only a "pseudo" one. It is not possible to |
| -- release the thread handle and free the system ressources from this |
| -- "pseudo" handle. So we really want to keep the real thread handle |
| -- set in System.Task_Primitives.Operations.Create_Task during the |
| -- thread creation. |
| |
| procedure Enter_Task (Self_ID : Task_ID) is |
| procedure Init_Float; |
| pragma Import (C, Init_Float, "__gnat_init_float"); |
| -- Properly initializes the FPU for x86 systems. |
| |
| begin |
| Specific.Set (Self_ID); |
| Init_Float; |
| |
| Self_ID.Common.LL.Thread_Id := GetCurrentThreadId; |
| |
| Lock_RTS; |
| |
| for J in Known_Tasks'Range loop |
| if Known_Tasks (J) = null then |
| Known_Tasks (J) := Self_ID; |
| Self_ID.Known_Tasks_Index := J; |
| exit; |
| end if; |
| end loop; |
| |
| Unlock_RTS; |
| end Enter_Task; |
| |
| -------------- |
| -- New_ATCB -- |
| -------------- |
| |
| function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is |
| begin |
| return new Ada_Task_Control_Block (Entry_Num); |
| end New_ATCB; |
| |
| ------------------- |
| -- Is_Valid_Task -- |
| ------------------- |
| |
| function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task; |
| |
| ----------------------------- |
| -- Register_Foreign_Thread -- |
| ----------------------------- |
| |
| function Register_Foreign_Thread return Task_ID is |
| begin |
| if Is_Valid_Task then |
| return Self; |
| else |
| return Register_Foreign_Thread (GetCurrentThread); |
| end if; |
| end Register_Foreign_Thread; |
| |
| -------------------- |
| -- Initialize_TCB -- |
| -------------------- |
| |
| procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is |
| begin |
| -- Initialize thread ID to 0, this is needed to detect threads that |
| -- are not yet activated. |
| |
| Self_ID.Common.LL.Thread := 0; |
| |
| Initialize_Cond (Self_ID.Common.LL.CV'Access); |
| |
| if not Single_Lock then |
| Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level); |
| end if; |
| |
| Succeeded := True; |
| end Initialize_TCB; |
| |
| ----------------- |
| -- Create_Task -- |
| ----------------- |
| |
| procedure Create_Task |
| (T : Task_ID; |
| Wrapper : System.Address; |
| Stack_Size : System.Parameters.Size_Type; |
| Priority : System.Any_Priority; |
| Succeeded : out Boolean) |
| is |
| hTask : HANDLE; |
| TaskId : aliased DWORD; |
| pTaskParameter : System.OS_Interface.PVOID; |
| dwStackSize : DWORD; |
| Result : DWORD; |
| Entry_Point : PTHREAD_START_ROUTINE; |
| |
| function To_PTHREAD_START_ROUTINE is new |
| Unchecked_Conversion (System.Address, PTHREAD_START_ROUTINE); |
| |
| begin |
| pTaskParameter := To_Address (T); |
| |
| if Stack_Size = Unspecified_Size then |
| dwStackSize := DWORD (Default_Stack_Size); |
| |
| elsif Stack_Size < Minimum_Stack_Size then |
| dwStackSize := DWORD (Minimum_Stack_Size); |
| |
| else |
| dwStackSize := DWORD (Stack_Size); |
| end if; |
| |
| Entry_Point := To_PTHREAD_START_ROUTINE (Wrapper); |
| |
| hTask := CreateThread |
| (null, |
| dwStackSize, |
| Entry_Point, |
| pTaskParameter, |
| DWORD (Create_Suspended), |
| TaskId'Unchecked_Access); |
| |
| -- Step 1: Create the thread in blocked mode |
| |
| if hTask = 0 then |
| raise Storage_Error; |
| end if; |
| |
| -- Step 2: set its TCB |
| |
| T.Common.LL.Thread := hTask; |
| |
| -- Step 3: set its priority (child has inherited priority from parent) |
| |
| Set_Priority (T, Priority); |
| |
| if Time_Slice_Val = 0 or else FIFO_Within_Priorities then |
| -- Here we need Annex E semantics so we disable the NT priority |
| -- boost. A priority boost is temporarily given by the system to a |
| -- thread when it is taken out of a wait state. |
| |
| SetThreadPriorityBoost (hTask, DisablePriorityBoost => True); |
| end if; |
| |
| -- Step 4: Now, start it for good: |
| |
| Result := ResumeThread (hTask); |
| pragma Assert (Result = 1); |
| |
| Succeeded := Result = 1; |
| end Create_Task; |
| |
| ------------------ |
| -- Finalize_TCB -- |
| ------------------ |
| |
| procedure Finalize_TCB (T : Task_ID) is |
| Self_ID : Task_ID := T; |
| Result : DWORD; |
| Succeeded : BOOL; |
| Is_Self : constant Boolean := T = Self; |
| |
| procedure Free is new |
| Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID); |
| |
| begin |
| if not Single_Lock then |
| Finalize_Lock (T.Common.LL.L'Access); |
| end if; |
| |
| Finalize_Cond (T.Common.LL.CV'Access); |
| |
| if T.Known_Tasks_Index /= -1 then |
| Known_Tasks (T.Known_Tasks_Index) := null; |
| end if; |
| |
| if Self_ID.Common.LL.Thread /= 0 then |
| |
| -- This task has been activated. Wait for the thread to terminate |
| -- then close it. this is needed to release system ressources. |
| |
| Result := WaitForSingleObject (T.Common.LL.Thread, Wait_Infinite); |
| pragma Assert (Result /= WAIT_FAILED); |
| Succeeded := CloseHandle (T.Common.LL.Thread); |
| pragma Assert (Succeeded = True); |
| end if; |
| |
| Free (Self_ID); |
| |
| if Is_Self then |
| Succeeded := TlsSetValue (TlsIndex, System.Null_Address); |
| pragma Assert (Succeeded = True); |
| end if; |
| end Finalize_TCB; |
| |
| --------------- |
| -- Exit_Task -- |
| --------------- |
| |
| procedure Exit_Task is |
| begin |
| Specific.Set (null); |
| end Exit_Task; |
| |
| ---------------- |
| -- Abort_Task -- |
| ---------------- |
| |
| procedure Abort_Task (T : Task_ID) is |
| pragma Unreferenced (T); |
| begin |
| null; |
| end Abort_Task; |
| |
| ---------------------- |
| -- Environment_Task -- |
| ---------------------- |
| |
| function Environment_Task return Task_ID is |
| begin |
| return Environment_Task_ID; |
| end Environment_Task; |
| |
| -------------- |
| -- Lock_RTS -- |
| -------------- |
| |
| procedure Lock_RTS is |
| begin |
| Write_Lock (Single_RTS_Lock'Access, Global_Lock => True); |
| end Lock_RTS; |
| |
| ---------------- |
| -- Unlock_RTS -- |
| ---------------- |
| |
| procedure Unlock_RTS is |
| begin |
| Unlock (Single_RTS_Lock'Access, Global_Lock => True); |
| end Unlock_RTS; |
| |
| ---------------- |
| -- Initialize -- |
| ---------------- |
| |
| procedure Initialize (Environment_Task : Task_ID) is |
| Discard : BOOL; |
| pragma Unreferenced (Discard); |
| |
| begin |
| Environment_Task_ID := Environment_Task; |
| |
| if Time_Slice_Val = 0 or else FIFO_Within_Priorities then |
| |
| -- Here we need Annex E semantics, switch the current process to the |
| -- High_Priority_Class. |
| |
| Discard := |
| OS_Interface.SetPriorityClass |
| (GetCurrentProcess, High_Priority_Class); |
| |
| -- ??? In theory it should be possible to use the priority class |
| -- Realtime_Prioriry_Class but we suspect a bug in the NT scheduler |
| -- which prevents (in some obscure cases) a thread to get on top of |
| -- the running queue by another thread of lower priority. For |
| -- example cxd8002 ACATS test freeze. |
| end if; |
| |
| TlsIndex := TlsAlloc; |
| |
| -- Initialize the lock used to synchronize chain of all ATCBs. |
| |
| Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); |
| |
| Environment_Task.Common.LL.Thread := GetCurrentThread; |
| Enter_Task (Environment_Task); |
| end Initialize; |
| |
| --------------------- |
| -- Monotonic_Clock -- |
| --------------------- |
| |
| function Monotonic_Clock return Duration |
| renames System.OS_Primitives.Monotonic_Clock; |
| |
| ------------------- |
| -- RT_Resolution -- |
| ------------------- |
| |
| function RT_Resolution return Duration is |
| begin |
| return 0.000_001; -- 1 micro-second |
| end RT_Resolution; |
| |
| ---------------- |
| -- Check_Exit -- |
| ---------------- |
| |
| -- Dummy versions. The only currently working versions is for solaris |
| -- (native). |
| |
| function Check_Exit (Self_ID : ST.Task_ID) return Boolean is |
| pragma Unreferenced (Self_ID); |
| |
| begin |
| return True; |
| end Check_Exit; |
| |
| -------------------- |
| -- Check_No_Locks -- |
| -------------------- |
| |
| function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is |
| pragma Unreferenced (Self_ID); |
| |
| begin |
| return True; |
| end Check_No_Locks; |
| |
| ------------------ |
| -- Suspend_Task -- |
| ------------------ |
| |
| function Suspend_Task |
| (T : ST.Task_ID; |
| Thread_Self : Thread_Id) |
| return Boolean |
| is |
| begin |
| if T.Common.LL.Thread /= Thread_Self then |
| return SuspendThread (T.Common.LL.Thread) = NO_ERROR; |
| else |
| return True; |
| end if; |
| end Suspend_Task; |
| |
| ----------------- |
| -- Resume_Task -- |
| ----------------- |
| |
| function Resume_Task |
| (T : ST.Task_ID; |
| Thread_Self : Thread_Id) |
| return Boolean |
| is |
| begin |
| if T.Common.LL.Thread /= Thread_Self then |
| return ResumeThread (T.Common.LL.Thread) = NO_ERROR; |
| else |
| return True; |
| end if; |
| end Resume_Task; |
| |
| end System.Task_Primitives.Operations; |
