| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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 -- |
| -- -- |
| -- $Revision: 1.1 $ |
| -- -- |
| -- Copyright (C) 1991-2001 Florida State University -- |
| -- -- |
| -- 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. It is -- |
| -- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- |
| -- State University (http://www.gnat.com). -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This is an OS/2 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 size_t |
| |
| with Interfaces.C.Strings; |
| -- used for Null_Ptr |
| |
| with Interfaces.OS2Lib.Errors; |
| with Interfaces.OS2Lib.Threads; |
| with Interfaces.OS2Lib.Synchronization; |
| |
| with System.Parameters; |
| -- used for Size_Type |
| |
| with System.Tasking; |
| -- used for Task_ID |
| |
| with System.Parameters; |
| -- used for Size_Type |
| |
| with System.Soft_Links; |
| -- used for Defer/Undefer_Abort |
| |
| -- 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 |
| -- Clock |
| |
| with Unchecked_Conversion; |
| with Unchecked_Deallocation; |
| |
| package body System.Task_Primitives.Operations is |
| |
| package IC renames Interfaces.C; |
| package ICS renames Interfaces.C.Strings; |
| package OSP renames System.OS_Primitives; |
| package SSL renames System.Soft_Links; |
| |
| use Interfaces.OS2Lib; |
| use Interfaces.OS2Lib.Errors; |
| use Interfaces.OS2Lib.Threads; |
| use Interfaces.OS2Lib.Synchronization; |
| use System.Tasking.Debug; |
| use System.Tasking; |
| use System.OS_Interface; |
| use Interfaces.C; |
| use System.OS_Primitives; |
| |
| ---------------------- |
| -- Local Constants -- |
| ---------------------- |
| |
| Max_Locks_Per_Task : constant := 100; |
| Suppress_Owner_Check : constant Boolean := False; |
| |
| ------------------ |
| -- Local Types -- |
| ------------------ |
| |
| type Microseconds is new IC.long; |
| subtype Lock_Range is Integer range 0 .. Max_Locks_Per_Task; |
| |
| ------------------ |
| -- Local Data -- |
| ------------------ |
| |
| -- The OS/2 DosAllocThreadLocalMemory API is used to allocate our TCB_Ptr. |
| |
| -- This API reserves a small range of virtual addresses that is backed |
| -- by different physical memory for each running thread. In this case we |
| -- create a pointer at a fixed address that points to the TCB_Ptr for the |
| -- running thread. So all threads will be able to query and update their |
| -- own TCB_Ptr without destroying the TCB_Ptr of other threads. |
| |
| type Thread_Local_Data is record |
| Self_ID : Task_ID; -- ID of the current thread |
| Lock_Prio_Level : Lock_Range; -- Nr of priority changes due to locks |
| |
| -- ... room for expansion here, if we decide to make access to |
| -- jump-buffer and exception stack more efficient in future |
| end record; |
| |
| type Access_Thread_Local_Data is access all Thread_Local_Data; |
| |
| -- Pointer to Thread Local Data |
| Thread_Local_Data_Ptr : aliased Access_Thread_Local_Data; |
| |
| type PPTLD is access all Access_Thread_Local_Data; |
| |
| All_Tasks_L : aliased System.Task_Primitives.RTS_Lock; |
| -- See comments on locking rules in System.Tasking (spec). |
| |
| Environment_Task_ID : Task_ID; |
| -- A variable to hold Task_ID for the environment task. |
| |
| ----------------------- |
| -- Local Subprograms -- |
| ----------------------- |
| |
| function To_PPVOID is new Unchecked_Conversion (PPTLD, PPVOID); |
| function To_Address is new Unchecked_Conversion (Task_ID, System.Address); |
| function To_PFNTHREAD is |
| new Unchecked_Conversion (System.Address, PFNTHREAD); |
| |
| function To_MS (D : Duration) return ULONG; |
| |
| procedure Set_Temporary_Priority |
| (T : in Task_ID; |
| New_Priority : in System.Any_Priority); |
| |
| ----------- |
| -- To_MS -- |
| ----------- |
| |
| function To_MS (D : Duration) return ULONG is |
| begin |
| return ULONG (D * 1_000); |
| end To_MS; |
| |
| ----------- |
| -- Clock -- |
| ----------- |
| |
| function Monotonic_Clock return Duration renames OSP.Monotonic_Clock; |
| |
| ------------------- |
| -- RT_Resolution -- |
| ------------------- |
| |
| function RT_Resolution return Duration is |
| begin |
| return 10#1.0#E-6; |
| end RT_Resolution; |
| |
| ------------------- |
| -- Abort_Handler -- |
| ------------------- |
| |
| -- OS/2 only has limited support for asynchronous signals. |
| -- It seems not to be possible to jump out of an exception |
| -- handler or to change the execution context of the thread. |
| -- So asynchonous transfer of control is not supported. |
| |
| ------------------- |
| -- 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 |
| begin |
| null; |
| end Stack_Guard; |
| |
| -------------------- |
| -- Get_Thread_Id -- |
| -------------------- |
| |
| function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is |
| begin |
| return OSI.Thread_Id (T.Common.LL.Thread); |
| end Get_Thread_Id; |
| |
| ---------- |
| -- Self -- |
| ---------- |
| |
| function Self return Task_ID is |
| Self_ID : Task_ID renames Thread_Local_Data_Ptr.Self_ID; |
| |
| begin |
| -- Check that the thread local data has been initialized. |
| |
| pragma Assert |
| ((Thread_Local_Data_Ptr /= null |
| and then Thread_Local_Data_Ptr.Self_ID /= null)); |
| |
| return Self_ID; |
| end Self; |
| |
| --------------------- |
| -- Initialize_Lock -- |
| --------------------- |
| |
| procedure Initialize_Lock |
| (Prio : System.Any_Priority; |
| L : access Lock) |
| is |
| begin |
| if DosCreateMutexSem |
| (ICS.Null_Ptr, L.Mutex'Unchecked_Access, 0, False32) /= NO_ERROR |
| then |
| raise Storage_Error; |
| end if; |
| |
| pragma Assert (L.Mutex /= 0, "Error creating Mutex"); |
| L.Priority := Prio; |
| L.Owner_ID := Null_Address; |
| end Initialize_Lock; |
| |
| procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is |
| begin |
| if DosCreateMutexSem |
| (ICS.Null_Ptr, L.Mutex'Unchecked_Access, 0, False32) /= NO_ERROR |
| then |
| raise Storage_Error; |
| end if; |
| |
| pragma Assert (L.Mutex /= 0, "Error creating Mutex"); |
| |
| L.Priority := System.Any_Priority'Last; |
| L.Owner_ID := Null_Address; |
| end Initialize_Lock; |
| |
| ------------------- |
| -- Finalize_Lock -- |
| ------------------- |
| |
| procedure Finalize_Lock (L : access Lock) is |
| begin |
| Must_Not_Fail (DosCloseMutexSem (L.Mutex)); |
| end Finalize_Lock; |
| |
| procedure Finalize_Lock (L : access RTS_Lock) is |
| begin |
| Must_Not_Fail (DosCloseMutexSem (L.Mutex)); |
| end Finalize_Lock; |
| |
| ---------------- |
| -- Write_Lock -- |
| ---------------- |
| |
| procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is |
| Self_ID : constant Task_ID := Thread_Local_Data_Ptr.Self_ID; |
| Old_Priority : constant Any_Priority := |
| Self_ID.Common.LL.Current_Priority; |
| |
| begin |
| if L.Priority < Old_Priority then |
| Ceiling_Violation := True; |
| return; |
| end if; |
| |
| Ceiling_Violation := False; |
| |
| -- Increase priority before getting the lock |
| -- to prevent priority inversion |
| |
| Thread_Local_Data_Ptr.Lock_Prio_Level := |
| Thread_Local_Data_Ptr.Lock_Prio_Level + 1; |
| if L.Priority > Old_Priority then |
| Set_Temporary_Priority (Self_ID, L.Priority); |
| end if; |
| |
| -- Request the lock and then update the lock owner data |
| |
| Must_Not_Fail (DosRequestMutexSem (L.Mutex, SEM_INDEFINITE_WAIT)); |
| L.Owner_Priority := Old_Priority; |
| L.Owner_ID := Self_ID.all'Address; |
| end Write_Lock; |
| |
| procedure Write_Lock (L : access RTS_Lock) is |
| Self_ID : constant Task_ID := Thread_Local_Data_Ptr.Self_ID; |
| Old_Priority : constant Any_Priority := |
| Self_ID.Common.LL.Current_Priority; |
| |
| begin |
| -- Increase priority before getting the lock |
| -- to prevent priority inversion |
| |
| Thread_Local_Data_Ptr.Lock_Prio_Level := |
| Thread_Local_Data_Ptr.Lock_Prio_Level + 1; |
| |
| if L.Priority > Old_Priority then |
| Set_Temporary_Priority (Self_ID, L.Priority); |
| end if; |
| |
| -- Request the lock and then update the lock owner data |
| |
| Must_Not_Fail (DosRequestMutexSem (L.Mutex, SEM_INDEFINITE_WAIT)); |
| L.Owner_Priority := Old_Priority; |
| L.Owner_ID := Self_ID.all'Address; |
| end Write_Lock; |
| |
| procedure Write_Lock (T : Task_ID) is |
| begin |
| -- Request the lock and then update the lock owner data |
| |
| Must_Not_Fail |
| (DosRequestMutexSem (T.Common.LL.L.Mutex, SEM_INDEFINITE_WAIT)); |
| T.Common.LL.L.Owner_ID := Null_Address; |
| end Write_Lock; |
| |
| --------------- |
| -- Read_Lock -- |
| --------------- |
| |
| procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) |
| renames Write_Lock; |
| |
| ------------ |
| -- Unlock -- |
| ------------ |
| |
| procedure Unlock (L : access Lock) is |
| Self_ID : constant Task_ID := Thread_Local_Data_Ptr.Self_ID; |
| Old_Priority : constant Any_Priority := L.Owner_Priority; |
| |
| begin |
| -- Check that this task holds the lock |
| |
| pragma Assert (Suppress_Owner_Check |
| or else L.Owner_ID = Self_ID.all'Address); |
| |
| -- Upate the owner data |
| |
| L.Owner_ID := Null_Address; |
| |
| -- Do the actual unlocking. No more references |
| -- to owner data of L after this point. |
| |
| Must_Not_Fail (DosReleaseMutexSem (L.Mutex)); |
| |
| -- Reset priority after unlocking to avoid priority inversion |
| |
| Thread_Local_Data_Ptr.Lock_Prio_Level := |
| Thread_Local_Data_Ptr.Lock_Prio_Level - 1; |
| if L.Priority /= Old_Priority then |
| Set_Temporary_Priority (Self_ID, Old_Priority); |
| end if; |
| end Unlock; |
| |
| procedure Unlock (L : access RTS_Lock) is |
| Self_ID : constant Task_ID := Thread_Local_Data_Ptr.Self_ID; |
| Old_Priority : constant Any_Priority := L.Owner_Priority; |
| |
| begin |
| -- Check that this task holds the lock |
| |
| pragma Assert (Suppress_Owner_Check |
| or else L.Owner_ID = Self_ID.all'Address); |
| |
| -- Upate the owner data |
| |
| L.Owner_ID := Null_Address; |
| |
| -- Do the actual unlocking. No more references |
| -- to owner data of L after this point. |
| |
| Must_Not_Fail (DosReleaseMutexSem (L.Mutex)); |
| |
| -- Reset priority after unlocking to avoid priority inversion |
| Thread_Local_Data_Ptr.Lock_Prio_Level := |
| Thread_Local_Data_Ptr.Lock_Prio_Level - 1; |
| |
| if L.Priority /= Old_Priority then |
| Set_Temporary_Priority (Self_ID, Old_Priority); |
| end if; |
| end Unlock; |
| |
| procedure Unlock (T : Task_ID) is |
| begin |
| -- Check the owner data |
| |
| pragma Assert (Suppress_Owner_Check |
| or else T.Common.LL.L.Owner_ID = Null_Address); |
| |
| -- Do the actual unlocking. No more references |
| -- to owner data of T.Common.LL.L after this point. |
| |
| Must_Not_Fail (DosReleaseMutexSem (T.Common.LL.L.Mutex)); |
| end Unlock; |
| |
| ----------- |
| -- Sleep -- |
| ----------- |
| |
| procedure Sleep (Self_ID : Task_ID; |
| Reason : System.Tasking.Task_States) is |
| Count : aliased ULONG; -- Used to store dummy result |
| |
| begin |
| -- Must reset Cond BEFORE L is unlocked. |
| |
| Sem_Must_Not_Fail |
| (DosResetEventSem (Self_ID.Common.LL.CV, Count'Unchecked_Access)); |
| Unlock (Self_ID); |
| |
| -- No problem if we are interrupted here. |
| -- If the condition is signaled, DosWaitEventSem will simply not block. |
| |
| Sem_Must_Not_Fail |
| (DosWaitEventSem (Self_ID.Common.LL.CV, SEM_INDEFINITE_WAIT)); |
| |
| -- Since L was previously accquired, lock operation should not fail. |
| |
| Write_Lock (Self_ID); |
| 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. |
| |
| -- Pre-assertion: Cond is posted |
| -- Self is locked. |
| |
| -- Post-assertion: Cond is posted |
| -- Self is locked. |
| |
| 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 |
| Check_Time : constant Duration := OSP.Monotonic_Clock; |
| Rel_Time : Duration; |
| Abs_Time : Duration; |
| Time_Out : ULONG; |
| Result : APIRET; |
| Count : aliased ULONG; -- Used to store dummy result |
| |
| begin |
| -- Must reset Cond BEFORE Self_ID is unlocked. |
| |
| Sem_Must_Not_Fail |
| (DosResetEventSem (Self_ID.Common.LL.CV, |
| Count'Unchecked_Access)); |
| Unlock (Self_ID); |
| |
| 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; |
| |
| Time_Out := To_MS (Rel_Time); |
| Result := DosWaitEventSem (Self_ID.Common.LL.CV, Time_Out); |
| pragma Assert |
| ((Result = NO_ERROR or Result = ERROR_TIMEOUT |
| or Result = ERROR_INTERRUPT)); |
| |
| -- ??? |
| -- What to do with error condition ERROR_NOT_ENOUGH_MEMORY? Can |
| -- we raise an exception here? And what about ERROR_INTERRUPT? |
| -- Should that be treated as a simple timeout? |
| -- For now, consider only ERROR_TIMEOUT to be a timeout. |
| |
| exit when Abs_Time <= OSP.Monotonic_Clock; |
| |
| if Result /= ERROR_TIMEOUT then |
| -- somebody may have called Wakeup for us |
| Timedout := False; |
| exit; |
| end if; |
| |
| Rel_Time := Abs_Time - OSP.Monotonic_Clock; |
| end loop; |
| end if; |
| |
| -- Ensure post-condition |
| |
| Write_Lock (Self_ID); |
| |
| if Timedout then |
| Sem_Must_Not_Fail (DosPostEventSem (Self_ID.Common.LL.CV)); |
| end if; |
| end Timed_Sleep; |
| |
| ----------------- |
| -- Timed_Delay -- |
| ----------------- |
| |
| procedure Timed_Delay |
| (Self_ID : Task_ID; |
| Time : Duration; |
| Mode : ST.Delay_Modes) |
| is |
| Check_Time : constant Duration := OSP.Monotonic_Clock; |
| Rel_Time : Duration; |
| Abs_Time : Duration; |
| Timedout : Boolean := True; |
| Time_Out : ULONG; |
| Result : APIRET; |
| Count : aliased ULONG; -- Used to store dummy result |
| |
| 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; |
| Write_Lock (Self_ID); |
| |
| -- Must reset Cond BEFORE Self_ID is unlocked. |
| |
| Sem_Must_Not_Fail |
| (DosResetEventSem (Self_ID.Common.LL.CV, |
| Count'Unchecked_Access)); |
| Unlock (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; |
| |
| Time_Out := To_MS (Rel_Time); |
| Result := DosWaitEventSem (Self_ID.Common.LL.CV, Time_Out); |
| |
| exit when Abs_Time <= OSP.Monotonic_Clock; |
| |
| Rel_Time := Abs_Time - OSP.Monotonic_Clock; |
| end loop; |
| |
| Self_ID.Common.State := Runnable; |
| Timedout := Result = ERROR_TIMEOUT; |
| end if; |
| |
| -- Ensure post-condition |
| |
| Write_Lock (Self_ID); |
| |
| if Timedout then |
| Sem_Must_Not_Fail (DosPostEventSem (Self_ID.Common.LL.CV)); |
| end if; |
| |
| Unlock (Self_ID); |
| System.OS_Interface.Yield; |
| SSL.Abort_Undefer.all; |
| end Timed_Delay; |
| |
| ------------ |
| -- Wakeup -- |
| ------------ |
| |
| procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is |
| begin |
| Sem_Must_Not_Fail (DosPostEventSem (T.Common.LL.CV)); |
| end Wakeup; |
| |
| ----------- |
| -- Yield -- |
| ----------- |
| |
| procedure Yield (Do_Yield : Boolean := True) is |
| begin |
| if Do_Yield then |
| System.OS_Interface.Yield; |
| end if; |
| end Yield; |
| |
| ---------------------------- |
| -- Set_Temporary_Priority -- |
| ---------------------------- |
| |
| procedure Set_Temporary_Priority |
| (T : Task_ID; |
| New_Priority : System.Any_Priority) |
| is |
| use Interfaces.C; |
| Delta_Priority : Integer; |
| |
| begin |
| -- When Lock_Prio_Level = 0, we always need to set the |
| -- Active_Priority. In this way we can make priority changes |
| -- due to locking independent of those caused by calling |
| -- Set_Priority. |
| |
| if Thread_Local_Data_Ptr.Lock_Prio_Level = 0 |
| or else New_Priority < T.Common.Current_Priority |
| then |
| Delta_Priority := T.Common.Current_Priority - |
| T.Common.LL.Current_Priority; |
| else |
| Delta_Priority := New_Priority - T.Common.LL.Current_Priority; |
| end if; |
| |
| if Delta_Priority /= 0 then |
| |
| -- ??? There is a race-condition here |
| -- The TCB is updated before the system call to make |
| -- pre-emption in the critical section less likely. |
| |
| T.Common.LL.Current_Priority := |
| T.Common.LL.Current_Priority + Delta_Priority; |
| Must_Not_Fail |
| (DosSetPriority (Scope => PRTYS_THREAD, |
| Class => PRTYC_NOCHANGE, |
| Delta_P => IC.long (Delta_Priority), |
| PorTid => T.Common.LL.Thread)); |
| end if; |
| end Set_Temporary_Priority; |
| |
| ------------------ |
| -- Set_Priority -- |
| ------------------ |
| |
| procedure Set_Priority |
| (T : Task_ID; |
| Prio : System.Any_Priority; |
| Loss_Of_Inheritance : Boolean := False) is |
| begin |
| T.Common.Current_Priority := Prio; |
| Set_Temporary_Priority (T, 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 -- |
| ---------------- |
| |
| procedure Enter_Task (Self_ID : Task_ID) is |
| begin |
| |
| -- Initialize thread local data. Must be done first. |
| |
| Thread_Local_Data_Ptr.Self_ID := Self_ID; |
| Thread_Local_Data_Ptr.Lock_Prio_Level := 0; |
| |
| Lock_All_Tasks_List; |
| for I in Known_Tasks'Range loop |
| if Known_Tasks (I) = null then |
| Known_Tasks (I) := Self_ID; |
| Self_ID.Known_Tasks_Index := I; |
| exit; |
| end if; |
| end loop; |
| Unlock_All_Tasks_List; |
| |
| -- For OS/2, we can set Self_ID.Common.LL.Thread in |
| -- Create_Task, since the thread is created suspended. |
| -- That is, there is no danger of the thread racing ahead |
| -- and trying to reference Self_ID.Common.LL.Thread before it |
| -- has been initialized. |
| |
| -- .... Do we need to do anything with signals for OS/2 ??? |
| null; |
| 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; |
| |
| ---------------------- |
| -- Initialize_TCB -- |
| ---------------------- |
| |
| procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is |
| begin |
| if DosCreateEventSem (ICS.Null_Ptr, |
| Self_ID.Common.LL.CV'Unchecked_Access, 0, True32) = NO_ERROR |
| then |
| if DosCreateMutexSem (ICS.Null_Ptr, |
| Self_ID.Common.LL.L.Mutex'Unchecked_Access, 0, False32) /= NO_ERROR |
| then |
| Succeeded := False; |
| Must_Not_Fail (DosCloseEventSem (Self_ID.Common.LL.CV)); |
| else |
| Succeeded := True; |
| end if; |
| |
| pragma Assert (Self_ID.Common.LL.L.Mutex /= 0); |
| |
| -- We now want to do the equivalent of: |
| |
| -- Initialize_Lock |
| -- (Self_ID.Common.LL.L'Unchecked_Access, ATCB_Level); |
| |
| -- But we avoid that because the Initialize_TCB routine has an |
| -- exception handler, and it is too early for us to deal with |
| -- installing handlers (see comment below), so we do our own |
| -- Initialize_Lock operation manually. |
| |
| Self_ID.Common.LL.L.Priority := System.Any_Priority'Last; |
| Self_ID.Common.LL.L.Owner_ID := Null_Address; |
| |
| else |
| Succeeded := False; |
| end if; |
| |
| -- Note: at one time we had anb exception handler here, whose code |
| -- was as follows: |
| |
| -- exception |
| |
| -- Assumes any failure must be due to insufficient resources |
| |
| -- when Storage_Error => |
| -- Must_Not_Fail (DosCloseEventSem (Self_ID.Common.LL.CV)); |
| -- Succeeded := False; |
| |
| -- but that won't work with the old exception scheme, since it would |
| -- result in messing with Jmpbuf values too early. If and when we get |
| -- switched entirely to the new zero-cost exception scheme, we could |
| -- put this handler back in! |
| |
| 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 |
| Result : aliased APIRET; |
| Adjusted_Stack_Size : System.Parameters.Size_Type; |
| use System.Parameters; |
| |
| begin |
| -- In OS/2 the allocated stack size should be based on the |
| -- amount of address space that should be reserved for the stack. |
| -- Actual memory will only be used when the stack is touched anyway. |
| |
| -- The new minimum size is 12 kB, although the EMX docs |
| -- recommend a minimum size of 32 kB. (The original was 4 kB) |
| -- Systems that use many tasks (say > 30) and require much |
| -- memory may run out of virtual address space, since OS/2 |
| -- has a per-process limit of 512 MB, of which max. 300 MB is |
| -- usable in practise. |
| |
| if Stack_Size = Unspecified_Size then |
| Adjusted_Stack_Size := Default_Stack_Size; |
| |
| elsif Stack_Size < Minimum_Stack_Size then |
| Adjusted_Stack_Size := Minimum_Stack_Size; |
| |
| else |
| Adjusted_Stack_Size := Stack_Size; |
| end if; |
| |
| -- GB970222: |
| -- Because DosCreateThread is called directly here, the |
| -- C RTL doesn't get initialized for the new thead. EMX by |
| -- default uses per-thread local heaps in addition to the |
| -- global heap. There might be other effects of by-passing the |
| -- C library here. |
| |
| -- When using _beginthread the newly created thread is not |
| -- blocked initially. Does this matter or can I create the |
| -- thread running anyway? The LL.Thread variable will be set |
| -- anyway because the variable is passed by reference to OS/2. |
| |
| T.Common.LL.Wrapper := To_PFNTHREAD (Wrapper); |
| |
| -- The OS implicitly gives the new task the priority of this task. |
| |
| T.Common.LL.Current_Priority := Self.Common.LL.Current_Priority; |
| |
| -- If task was locked before activator task was |
| -- initialized, assume it has OS standard priority |
| |
| if T.Common.LL.L.Owner_Priority not in Any_Priority'Range then |
| T.Common.LL.L.Owner_Priority := 1; |
| end if; |
| |
| -- Create the thread, in blocked mode |
| |
| Result := DosCreateThread |
| (F_ptid => T.Common.LL.Thread'Unchecked_Access, |
| pfn => T.Common.LL.Wrapper, |
| param => To_Address (T), |
| flag => Block_Child + Commit_Stack, |
| cbStack => ULONG (Adjusted_Stack_Size)); |
| |
| Succeeded := (Result = NO_ERROR); |
| |
| if not Succeeded then |
| return; |
| end if; |
| |
| -- Set the new thread's priority |
| -- (child has inherited priority from parent) |
| |
| Set_Priority (T, Priority); |
| |
| -- Start the thread executing |
| |
| Must_Not_Fail (DosResumeThread (T.Common.LL.Thread)); |
| |
| end Create_Task; |
| |
| ------------------ |
| -- Finalize_TCB -- |
| ------------------ |
| |
| procedure Finalize_TCB (T : Task_ID) is |
| Tmp : Task_ID := T; |
| |
| procedure Free is new |
| Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID); |
| begin |
| Must_Not_Fail (DosCloseEventSem (T.Common.LL.CV)); |
| Finalize_Lock (T.Common.LL.L'Unchecked_Access); |
| if T.Known_Tasks_Index /= -1 then |
| Known_Tasks (T.Known_Tasks_Index) := null; |
| end if; |
| Free (Tmp); |
| end Finalize_TCB; |
| |
| --------------- |
| -- Exit_Task -- |
| --------------- |
| |
| procedure Exit_Task is |
| begin |
| DosExit (EXIT_THREAD, 0); |
| |
| -- Do not finalize TCB here. |
| -- GNARL layer is responsible for that. |
| |
| end Exit_Task; |
| |
| ---------------- |
| -- Abort_Task -- |
| ---------------- |
| |
| procedure Abort_Task (T : Task_ID) is |
| begin |
| null; |
| |
| -- Task abortion not implemented yet. |
| -- Should perform other action ??? |
| |
| end Abort_Task; |
| |
| ---------------- |
| -- Check_Exit -- |
| ---------------- |
| |
| -- Dummy versions. The only currently working versions is for solaris |
| -- (native). |
| |
| function Check_Exit (Self_ID : ST.Task_ID) return Boolean is |
| begin |
| return Check_No_Locks (Self_ID); |
| end Check_Exit; |
| |
| -------------------- |
| -- Check_No_Locks -- |
| -------------------- |
| |
| function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is |
| TLD : constant Access_Thread_Local_Data := Thread_Local_Data_Ptr; |
| begin |
| return Self_ID = TLD.Self_ID |
| and then TLD.Lock_Prio_Level = 0; |
| end Check_No_Locks; |
| |
| ---------------------- |
| -- Environment_Task -- |
| ---------------------- |
| |
| function Environment_Task return Task_ID is |
| begin |
| return Environment_Task_ID; |
| end Environment_Task; |
| |
| ------------------------- |
| -- Lock_All_Tasks_List -- |
| ------------------------- |
| |
| procedure Lock_All_Tasks_List is |
| begin |
| Write_Lock (All_Tasks_L'Access); |
| end Lock_All_Tasks_List; |
| |
| --------------------------- |
| -- Unlock_All_Tasks_List -- |
| --------------------------- |
| |
| procedure Unlock_All_Tasks_List is |
| begin |
| Unlock (All_Tasks_L'Access); |
| end Unlock_All_Tasks_List; |
| |
| ------------------ |
| -- Suspend_Task -- |
| ------------------ |
| |
| function Suspend_Task |
| (T : ST.Task_ID; |
| Thread_Self : Thread_Id) return Boolean is |
| begin |
| if Thread_Id (T.Common.LL.Thread) /= Thread_Self then |
| return DosSuspendThread (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 Thread_Id (T.Common.LL.Thread) /= Thread_Self then |
| return DosResumeThread (T.Common.LL.Thread) = NO_ERROR; |
| else |
| return True; |
| end if; |
| end Resume_Task; |
| |
| ---------------- |
| -- Initialize -- |
| ---------------- |
| |
| procedure Initialize (Environment_Task : Task_ID) is |
| Succeeded : Boolean; |
| |
| begin |
| Environment_Task_ID := Environment_Task; |
| |
| Initialize_Lock (All_Tasks_L'Access, All_Tasks_Level); |
| -- Initialize the lock used to synchronize chain of all ATCBs. |
| |
| -- Set ID of environment task. |
| |
| Thread_Local_Data_Ptr.Self_ID := Environment_Task; |
| Environment_Task.Common.LL.Thread := 1; -- By definition |
| |
| -- This priority is unknown in fact. |
| -- If actual current priority is different, |
| -- it will get synchronized later on anyway. |
| |
| Environment_Task.Common.LL.Current_Priority := |
| Environment_Task.Common.Current_Priority; |
| |
| -- Initialize TCB for this task. |
| -- This includes all the normal task-external initialization. |
| -- This is also done by Initialize_ATCB, why ??? |
| |
| Initialize_TCB (Environment_Task, Succeeded); |
| |
| -- Consider raising Storage_Error, |
| -- if propagation can be tolerated ??? |
| |
| pragma Assert (Succeeded); |
| |
| -- Do normal task-internal initialization, |
| -- which depends on an initialized TCB. |
| |
| Enter_Task (Environment_Task); |
| |
| -- Insert here any other special |
| -- initialization needed for the environment task. |
| |
| end Initialize; |
| |
| begin |
| -- Initialize pointer to task local data. |
| -- This is done once, for all tasks. |
| |
| Must_Not_Fail (DosAllocThreadLocalMemory |
| ((Thread_Local_Data'Size + 31) / 32, -- nr of 32-bit words |
| To_PPVOID (Thread_Local_Data_Ptr'Access))); |
| |
| -- Initialize thread local data for main thread |
| |
| Thread_Local_Data_Ptr.Self_ID := null; |
| Thread_Local_Data_Ptr.Lock_Prio_Level := 0; |
| |
| end System.Task_Primitives.Operations; |
