1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
10 -- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
12 -- GNARL is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. It is --
31 -- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com). --
33 ------------------------------------------------------------------------------
35 -- This is a OpenVMS/Alpha version of this package
37 -- This package contains all the GNULL primitives that interface directly
38 -- with the underlying OS.
41 -- Turn off polling, we do not want ATC polling to take place during
42 -- tasking operations. It causes infinite loops and other problems.
44 with System.Tasking.Debug;
45 -- used for Known_Tasks
51 with System.Parameters;
55 -- used for Ada_Task_Control_Block
58 with System.Soft_Links;
59 -- used for Defer/Undefer_Abort
62 -- Note that we do not use System.Tasking.Initialization directly since
63 -- this is a higher level package that we shouldn't depend on. For example
64 -- when using the restricted run time, it is replaced by
65 -- System.Tasking.Restricted.Initialization
67 with System.OS_Primitives;
68 -- used for Delay_Modes
70 with Unchecked_Conversion;
71 with Unchecked_Deallocation;
73 package body System.Task_Primitives.Operations is
75 use System.Tasking.Debug;
78 use System.OS_Interface;
79 use System.Parameters;
80 use System.OS_Primitives;
81 use type System.OS_Primitives.OS_Time;
83 package SSL renames System.Soft_Links;
89 -- The followings are logically constants, but need to be initialized
92 ATCB_Key : aliased pthread_key_t;
93 -- Key used to find the Ada Task_ID associated with a thread
95 Single_RTS_Lock : aliased RTS_Lock;
96 -- This is a lock to allow only one thread of control in the RTS at
97 -- a time; it is used to execute in mutual exclusion from all other tasks.
98 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
100 Environment_Task_ID : Task_ID;
101 -- A variable to hold Task_ID for the environment task.
103 Time_Slice_Val : Integer;
104 pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
106 Dispatching_Policy : Character;
107 pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
109 FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
110 -- Indicates whether FIFO_Within_Priorities is set.
112 -----------------------
113 -- Local Subprograms --
114 -----------------------
116 function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
118 function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
120 procedure Timer_Sleep_AST (ID : Address);
121 -- Signal the condition variable when AST fires.
123 procedure Timer_Sleep_AST (ID : Address) is
124 Result : Interfaces.C.int;
125 Self_ID : Task_ID := To_Task_ID (ID);
128 Self_ID.Common.LL.AST_Pending := False;
129 Result := pthread_cond_signal_int_np (Self_ID.Common.LL.CV'Access);
136 -- The underlying thread system sets a guard page at the
137 -- bottom of a thread stack, so nothing is needed.
138 -- ??? Check the comment above
140 procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
149 function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
151 return T.Common.LL.Thread;
158 function Self return Task_ID is
159 Result : System.Address;
162 Result := pthread_getspecific (ATCB_Key);
163 pragma Assert (Result /= System.Null_Address);
164 return To_Task_ID (Result);
167 ---------------------
168 -- Initialize_Lock --
169 ---------------------
171 -- Note: mutexes and cond_variables needed per-task basis are
172 -- initialized in Initialize_TCB and the Storage_Error is
173 -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
174 -- used in RTS is initialized before any status change of RTS.
175 -- Therefore rasing Storage_Error in the following routines
176 -- should be able to be handled safely.
178 procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is
179 Attributes : aliased pthread_mutexattr_t;
180 Result : Interfaces.C.int;
183 Result := pthread_mutexattr_init (Attributes'Access);
184 pragma Assert (Result = 0 or else Result = ENOMEM);
186 if Result = ENOMEM then
191 L.Prio := Interfaces.C.int (Prio);
193 Result := pthread_mutex_init (L.L'Access, Attributes'Access);
194 pragma Assert (Result = 0 or else Result = ENOMEM);
196 if Result = ENOMEM then
200 Result := pthread_mutexattr_destroy (Attributes'Access);
201 pragma Assert (Result = 0);
204 procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
205 Attributes : aliased pthread_mutexattr_t;
206 Result : Interfaces.C.int;
209 Result := pthread_mutexattr_init (Attributes'Access);
210 pragma Assert (Result = 0 or else Result = ENOMEM);
212 if Result = ENOMEM then
216 -- Don't use, see comment in s-osinte.ads about ERRORCHECK mutexes.
217 -- Result := pthread_mutexattr_settype_np
218 -- (Attributes'Access, PTHREAD_MUTEX_ERRORCHECK_NP);
219 -- pragma Assert (Result = 0);
221 -- Result := pthread_mutexattr_setprotocol
222 -- (Attributes'Access, PTHREAD_PRIO_PROTECT);
223 -- pragma Assert (Result = 0);
225 -- Result := pthread_mutexattr_setprioceiling
226 -- (Attributes'Access, Interfaces.C.int (System.Any_Priority'Last));
227 -- pragma Assert (Result = 0);
229 Result := pthread_mutex_init (L, Attributes'Access);
231 pragma Assert (Result = 0 or else Result = ENOMEM);
233 if Result = ENOMEM then
237 Result := pthread_mutexattr_destroy (Attributes'Access);
238 pragma Assert (Result = 0);
245 procedure Finalize_Lock (L : access Lock) is
246 Result : Interfaces.C.int;
248 Result := pthread_mutex_destroy (L.L'Access);
249 pragma Assert (Result = 0);
252 procedure Finalize_Lock (L : access RTS_Lock) is
253 Result : Interfaces.C.int;
255 Result := pthread_mutex_destroy (L);
256 pragma Assert (Result = 0);
263 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
264 Self_ID : constant Task_ID := Self;
265 All_Tasks_Link : constant Task_ID := Self.Common.All_Tasks_Link;
266 Current_Prio : System.Any_Priority;
267 Result : Interfaces.C.int;
270 Current_Prio := Get_Priority (Self_ID);
272 -- If there is no other tasks, no need to check priorities.
274 if All_Tasks_Link /= Null_Task
275 and then L.Prio < Interfaces.C.int (Current_Prio)
277 Ceiling_Violation := True;
281 Result := pthread_mutex_lock (L.L'Access);
282 pragma Assert (Result = 0);
284 Ceiling_Violation := False;
285 -- Why is this commented out ???
286 -- L.Prio_Save := Interfaces.C.int (Current_Prio);
287 -- Set_Priority (Self_ID, System.Any_Priority (L.Prio));
291 (L : access RTS_Lock; Global_Lock : Boolean := False)
293 Result : Interfaces.C.int;
295 if not Single_Lock or else Global_Lock then
296 Result := pthread_mutex_lock (L);
297 pragma Assert (Result = 0);
301 procedure Write_Lock (T : Task_ID) is
302 Result : Interfaces.C.int;
304 if not Single_Lock then
305 Result := pthread_mutex_lock (T.Common.LL.L'Access);
306 pragma Assert (Result = 0);
314 procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
316 Write_Lock (L, Ceiling_Violation);
323 procedure Unlock (L : access Lock) is
324 Result : Interfaces.C.int;
326 Result := pthread_mutex_unlock (L.L'Access);
327 pragma Assert (Result = 0);
330 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
331 Result : Interfaces.C.int;
333 if not Single_Lock or else Global_Lock then
334 Result := pthread_mutex_unlock (L);
335 pragma Assert (Result = 0);
339 procedure Unlock (T : Task_ID) is
340 Result : Interfaces.C.int;
342 if not Single_Lock then
343 Result := pthread_mutex_unlock (T.Common.LL.L'Access);
344 pragma Assert (Result = 0);
354 Reason : System.Tasking.Task_States)
356 Result : Interfaces.C.int;
359 Result := pthread_cond_wait
360 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
362 Result := pthread_cond_wait
363 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
366 -- EINTR is not considered a failure.
367 pragma Assert (Result = 0 or else Result = EINTR);
369 if Self_ID.Deferral_Level = 0
370 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
373 raise Standard'Abort_Signal;
381 procedure Timed_Sleep
384 Mode : ST.Delay_Modes;
385 Reason : System.Tasking.Task_States;
386 Timedout : out Boolean;
387 Yielded : out Boolean)
389 Sleep_Time : OS_Time;
390 Result : Interfaces.C.int;
391 Status : Cond_Value_Type;
397 Sleep_Time := To_OS_Time (Time, Mode);
399 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
400 or else Self_ID.Pending_Priority_Change
405 Self_ID.Common.LL.AST_Pending := True;
408 (Status, 0, Sleep_Time,
409 Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
411 if (Status and 1) /= 1 then
416 Result := pthread_cond_wait
417 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
420 Result := pthread_cond_wait
421 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
426 if not Self_ID.Common.LL.AST_Pending then
429 Sys_Cantim (Status, To_Address (Self_ID), 0);
430 pragma Assert ((Status and 1) = 1);
438 procedure Timed_Delay
441 Mode : ST.Delay_Modes)
443 Sleep_Time : OS_Time;
444 Result : Interfaces.C.int;
445 Status : Cond_Value_Type;
446 Yielded : Boolean := False;
449 -- Only the little window between deferring abort and
450 -- locking Self_ID is the reason we need to
451 -- check for pending abort and priority change below!
458 Write_Lock (Self_ID);
460 if Time /= 0.0 or else Mode /= Relative then
461 Sleep_Time := To_OS_Time (Time, Mode);
463 if Mode = Relative or else OS_Clock < Sleep_Time then
464 Self_ID.Common.State := Delay_Sleep;
465 Self_ID.Common.LL.AST_Pending := True;
468 (Status, 0, Sleep_Time,
469 Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
471 if (Status and 1) /= 1 then
476 if Self_ID.Pending_Priority_Change then
477 Self_ID.Pending_Priority_Change := False;
478 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
479 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
482 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
483 Sys_Cantim (Status, To_Address (Self_ID), 0);
484 pragma Assert ((Status and 1) = 1);
489 Result := pthread_cond_wait
490 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
492 Result := pthread_cond_wait
493 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
498 exit when not Self_ID.Common.LL.AST_Pending;
501 Self_ID.Common.State := Runnable;
512 Result := sched_yield;
515 SSL.Abort_Undefer.all;
518 ---------------------
519 -- Monotonic_Clock --
520 ---------------------
522 function Monotonic_Clock return Duration
523 renames System.OS_Primitives.Monotonic_Clock;
529 function RT_Resolution return Duration is
538 procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is
539 Result : Interfaces.C.int;
541 Result := pthread_cond_signal (T.Common.LL.CV'Access);
542 pragma Assert (Result = 0);
549 procedure Yield (Do_Yield : Boolean := True) is
550 Result : Interfaces.C.int;
553 Result := sched_yield;
561 procedure Set_Priority
563 Prio : System.Any_Priority;
564 Loss_Of_Inheritance : Boolean := False)
566 Result : Interfaces.C.int;
567 Param : aliased struct_sched_param;
569 T.Common.Current_Priority := Prio;
570 Param.sched_priority := Interfaces.C.int (Underlying_Priorities (Prio));
572 if Time_Slice_Val > 0 then
573 Result := pthread_setschedparam
574 (T.Common.LL.Thread, SCHED_RR, Param'Access);
576 elsif FIFO_Within_Priorities or else Time_Slice_Val = 0 then
577 Result := pthread_setschedparam
578 (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
581 Result := pthread_setschedparam
582 (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
585 pragma Assert (Result = 0);
592 function Get_Priority (T : Task_ID) return System.Any_Priority is
594 return T.Common.Current_Priority;
601 procedure Enter_Task (Self_ID : Task_ID) is
602 Result : Interfaces.C.int;
604 Self_ID.Common.LL.Thread := pthread_self;
606 -- It is not safe for the new task accept signals until it
607 -- has bound its TCB pointer to the thread with pthread_setspecific (),
608 -- since the handler wrappers use the TCB pointer
609 -- to restore the stack limit.
611 Result := pthread_setspecific (ATCB_Key, To_Address (Self_ID));
612 pragma Assert (Result = 0);
616 for J in Known_Tasks'Range loop
617 if Known_Tasks (J) = null then
618 Known_Tasks (J) := Self_ID;
619 Self_ID.Known_Tasks_Index := J;
631 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
633 return new Ada_Task_Control_Block (Entry_Num);
636 ----------------------
638 ----------------------
640 procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
641 Mutex_Attr : aliased pthread_mutexattr_t;
642 Result : Interfaces.C.int;
643 Cond_Attr : aliased pthread_condattr_t;
646 if not Single_Lock then
647 Result := pthread_mutexattr_init (Mutex_Attr'Access);
648 pragma Assert (Result = 0 or else Result = ENOMEM);
651 Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
653 pragma Assert (Result = 0 or else Result = ENOMEM);
661 Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
662 pragma Assert (Result = 0);
665 Result := pthread_condattr_init (Cond_Attr'Access);
666 pragma Assert (Result = 0 or else Result = ENOMEM);
669 Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
671 pragma Assert (Result = 0 or else Result = ENOMEM);
676 Self_ID.Common.LL.Exc_Stack_Ptr := new Exc_Stack_T;
677 SSL.Set_Exc_Stack_Addr
678 (To_Address (Self_ID),
679 Self_ID.Common.LL.Exc_Stack_Ptr (Exc_Stack_T'Last)'Address);
682 if not Single_Lock then
683 Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
684 pragma Assert (Result = 0);
690 Result := pthread_condattr_destroy (Cond_Attr'Access);
691 pragma Assert (Result = 0);
698 procedure Create_Task
700 Wrapper : System.Address;
701 Stack_Size : System.Parameters.Size_Type;
702 Priority : System.Any_Priority;
703 Succeeded : out Boolean)
705 Attributes : aliased pthread_attr_t;
706 Adjusted_Stack_Size : Interfaces.C.size_t;
707 Result : Interfaces.C.int;
709 function Thread_Body_Access is new
710 Unchecked_Conversion (System.Address, Thread_Body);
713 if Stack_Size = Unspecified_Size then
714 Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
716 elsif Stack_Size < Minimum_Stack_Size then
717 Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
720 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
723 -- Since the initial signal mask of a thread is inherited from the
724 -- creator, we need to set our local signal mask mask all signals
725 -- during the creation operation, to make sure the new thread is
726 -- not disturbed by signals before it has set its own Task_ID.
728 Result := pthread_attr_init (Attributes'Access);
729 pragma Assert (Result = 0 or else Result = ENOMEM);
736 Result := pthread_attr_setdetachstate
737 (Attributes'Access, PTHREAD_CREATE_DETACHED);
738 pragma Assert (Result = 0);
740 Result := pthread_attr_setstacksize
741 (Attributes'Access, Adjusted_Stack_Size);
742 pragma Assert (Result = 0);
744 -- This call may be unnecessary, not sure. ???
746 Result := pthread_attr_setinheritsched
747 (Attributes'Access, PTHREAD_EXPLICIT_SCHED);
748 pragma Assert (Result = 0);
750 Result := pthread_create
751 (T.Common.LL.Thread'Access,
753 Thread_Body_Access (Wrapper),
756 -- ENOMEM is a valid run-time error. Don't shut down.
758 pragma Assert (Result = 0
759 or else Result = EAGAIN or else Result = ENOMEM);
761 Succeeded := Result = 0;
763 Result := pthread_attr_destroy (Attributes'Access);
764 pragma Assert (Result = 0);
767 Set_Priority (T, Priority);
775 procedure Finalize_TCB (T : Task_ID) is
776 Result : Interfaces.C.int;
779 procedure Free is new
780 Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
782 procedure Free is new Unchecked_Deallocation
783 (Exc_Stack_T, Exc_Stack_Ptr_T);
786 if not Single_Lock then
787 Result := pthread_mutex_destroy (T.Common.LL.L'Access);
788 pragma Assert (Result = 0);
791 Result := pthread_cond_destroy (T.Common.LL.CV'Access);
792 pragma Assert (Result = 0);
794 if T.Known_Tasks_Index /= -1 then
795 Known_Tasks (T.Known_Tasks_Index) := null;
798 Free (T.Common.LL.Exc_Stack_Ptr);
806 procedure Exit_Task is
808 pthread_exit (System.Null_Address);
815 procedure Abort_Task (T : Task_ID) is
819 -- Why is this commented out ???
820 -- if T = Self and then T.Deferral_Level = 0
821 -- and then T.Pending_ATC_Level < T.ATC_Nesting_Level
823 -- raise Standard'Abort_Signal;
827 -- Interrupt Server_Tasks may be waiting on an event flag
829 if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
830 Wakeup (T, Interrupt_Server_Blocked_On_Event_Flag);
839 -- Dummy versions. The only currently working versions is for solaris
842 function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
851 function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
856 ----------------------
857 -- Environment_Task --
858 ----------------------
860 function Environment_Task return Task_ID is
862 return Environment_Task_ID;
863 end Environment_Task;
869 procedure Lock_RTS is
871 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
878 procedure Unlock_RTS is
880 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
887 function Suspend_Task
889 Thread_Self : Thread_Id) return Boolean is
900 Thread_Self : Thread_Id) return Boolean is
909 procedure Initialize (Environment_Task : Task_ID) is
911 Environment_Task_ID := Environment_Task;
913 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
914 -- Initialize the lock used to synchronize chain of all ATCBs.
916 Enter_Task (Environment_Task);
921 Result : Interfaces.C.int;
923 Result := pthread_key_create (ATCB_Key'Access, null);
924 pragma Assert (Result = 0);
926 end System.Task_Primitives.Operations;