------------------------------------------------------------------------------ -- -- -- 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: 1.57 $ -- -- -- 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-proces 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;