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 --
9 -- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
11 -- GNARL is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. It is --
30 -- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com). --
32 ------------------------------------------------------------------------------
34 -- This is a OpenVMS/Alpha version of this package
36 -- This package contains all the GNULL primitives that interface directly
37 -- with the underlying OS.
40 -- Turn off polling, we do not want ATC polling to take place during
41 -- tasking operations. It causes infinite loops and other problems.
43 with System.Tasking.Debug;
44 -- used for Known_Tasks
50 with System.Parameters;
54 -- used for Ada_Task_Control_Block
57 with System.Soft_Links;
58 -- used for Defer/Undefer_Abort
61 -- Note that we do not use System.Tasking.Initialization directly since
62 -- this is a higher level package that we shouldn't depend on. For example
63 -- when using the restricted run time, it is replaced by
64 -- System.Tasking.Restricted.Initialization
66 with System.OS_Primitives;
67 -- used for Delay_Modes
69 with Unchecked_Conversion;
70 with Unchecked_Deallocation;
72 package body System.Task_Primitives.Operations is
74 use System.Tasking.Debug;
77 use System.OS_Interface;
78 use System.Parameters;
79 use System.OS_Primitives;
80 use type System.OS_Primitives.OS_Time;
82 package SSL renames System.Soft_Links;
88 -- The followings are logically constants, but need to be initialized
91 ATCB_Key : aliased pthread_key_t;
92 -- Key used to find the Ada Task_ID associated with a thread
94 Single_RTS_Lock : aliased RTS_Lock;
95 -- This is a lock to allow only one thread of control in the RTS at
96 -- a time; it is used to execute in mutual exclusion from all other tasks.
97 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
99 Environment_Task_ID : Task_ID;
100 -- A variable to hold Task_ID for the environment task.
102 Time_Slice_Val : Integer;
103 pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
105 Dispatching_Policy : Character;
106 pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
108 FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
109 -- Indicates whether FIFO_Within_Priorities is set.
111 -----------------------
112 -- Local Subprograms --
113 -----------------------
115 function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
117 function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
119 procedure Timer_Sleep_AST (ID : Address);
120 -- Signal the condition variable when AST fires.
122 procedure Timer_Sleep_AST (ID : Address) is
123 Result : Interfaces.C.int;
124 Self_ID : Task_ID := To_Task_ID (ID);
127 Self_ID.Common.LL.AST_Pending := False;
128 Result := pthread_cond_signal_int_np (Self_ID.Common.LL.CV'Access);
135 -- The underlying thread system sets a guard page at the
136 -- bottom of a thread stack, so nothing is needed.
137 -- ??? Check the comment above
139 procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
148 function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
150 return T.Common.LL.Thread;
157 function Self return Task_ID is
158 Result : System.Address;
161 Result := pthread_getspecific (ATCB_Key);
162 pragma Assert (Result /= System.Null_Address);
163 return To_Task_ID (Result);
166 ---------------------
167 -- Initialize_Lock --
168 ---------------------
170 -- Note: mutexes and cond_variables needed per-task basis are
171 -- initialized in Initialize_TCB and the Storage_Error is
172 -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
173 -- used in RTS is initialized before any status change of RTS.
174 -- Therefore rasing Storage_Error in the following routines
175 -- should be able to be handled safely.
177 procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is
178 Attributes : aliased pthread_mutexattr_t;
179 Result : Interfaces.C.int;
182 Result := pthread_mutexattr_init (Attributes'Access);
183 pragma Assert (Result = 0 or else Result = ENOMEM);
185 if Result = ENOMEM then
190 L.Prio := Interfaces.C.int (Prio);
192 Result := pthread_mutex_init (L.L'Access, Attributes'Access);
193 pragma Assert (Result = 0 or else Result = ENOMEM);
195 if Result = ENOMEM then
199 Result := pthread_mutexattr_destroy (Attributes'Access);
200 pragma Assert (Result = 0);
203 procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
204 Attributes : aliased pthread_mutexattr_t;
205 Result : Interfaces.C.int;
208 Result := pthread_mutexattr_init (Attributes'Access);
209 pragma Assert (Result = 0 or else Result = ENOMEM);
211 if Result = ENOMEM then
215 -- Don't use, see comment in s-osinte.ads about ERRORCHECK mutexes.
216 -- Result := pthread_mutexattr_settype_np
217 -- (Attributes'Access, PTHREAD_MUTEX_ERRORCHECK_NP);
218 -- pragma Assert (Result = 0);
220 -- Result := pthread_mutexattr_setprotocol
221 -- (Attributes'Access, PTHREAD_PRIO_PROTECT);
222 -- pragma Assert (Result = 0);
224 -- Result := pthread_mutexattr_setprioceiling
225 -- (Attributes'Access, Interfaces.C.int (System.Any_Priority'Last));
226 -- pragma Assert (Result = 0);
228 Result := pthread_mutex_init (L, Attributes'Access);
230 pragma Assert (Result = 0 or else Result = ENOMEM);
232 if Result = ENOMEM then
236 Result := pthread_mutexattr_destroy (Attributes'Access);
237 pragma Assert (Result = 0);
244 procedure Finalize_Lock (L : access Lock) is
245 Result : Interfaces.C.int;
247 Result := pthread_mutex_destroy (L.L'Access);
248 pragma Assert (Result = 0);
251 procedure Finalize_Lock (L : access RTS_Lock) is
252 Result : Interfaces.C.int;
254 Result := pthread_mutex_destroy (L);
255 pragma Assert (Result = 0);
262 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
263 Self_ID : constant Task_ID := Self;
264 All_Tasks_Link : constant Task_ID := Self.Common.All_Tasks_Link;
265 Current_Prio : System.Any_Priority;
266 Result : Interfaces.C.int;
269 Current_Prio := Get_Priority (Self_ID);
271 -- If there is no other tasks, no need to check priorities.
273 if All_Tasks_Link /= Null_Task
274 and then L.Prio < Interfaces.C.int (Current_Prio)
276 Ceiling_Violation := True;
280 Result := pthread_mutex_lock (L.L'Access);
281 pragma Assert (Result = 0);
283 Ceiling_Violation := False;
284 -- Why is this commented out ???
285 -- L.Prio_Save := Interfaces.C.int (Current_Prio);
286 -- Set_Priority (Self_ID, System.Any_Priority (L.Prio));
290 (L : access RTS_Lock; Global_Lock : Boolean := False)
292 Result : Interfaces.C.int;
294 if not Single_Lock or else Global_Lock then
295 Result := pthread_mutex_lock (L);
296 pragma Assert (Result = 0);
300 procedure Write_Lock (T : Task_ID) is
301 Result : Interfaces.C.int;
303 if not Single_Lock then
304 Result := pthread_mutex_lock (T.Common.LL.L'Access);
305 pragma Assert (Result = 0);
313 procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
315 Write_Lock (L, Ceiling_Violation);
322 procedure Unlock (L : access Lock) is
323 Result : Interfaces.C.int;
325 Result := pthread_mutex_unlock (L.L'Access);
326 pragma Assert (Result = 0);
329 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
330 Result : Interfaces.C.int;
332 if not Single_Lock or else Global_Lock then
333 Result := pthread_mutex_unlock (L);
334 pragma Assert (Result = 0);
338 procedure Unlock (T : Task_ID) is
339 Result : Interfaces.C.int;
341 if not Single_Lock then
342 Result := pthread_mutex_unlock (T.Common.LL.L'Access);
343 pragma Assert (Result = 0);
353 Reason : System.Tasking.Task_States)
355 Result : Interfaces.C.int;
358 Result := pthread_cond_wait
359 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
361 Result := pthread_cond_wait
362 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
365 -- EINTR is not considered a failure.
366 pragma Assert (Result = 0 or else Result = EINTR);
368 if Self_ID.Deferral_Level = 0
369 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
372 raise Standard'Abort_Signal;
380 procedure Timed_Sleep
383 Mode : ST.Delay_Modes;
384 Reason : System.Tasking.Task_States;
385 Timedout : out Boolean;
386 Yielded : out Boolean)
388 Sleep_Time : OS_Time;
389 Result : Interfaces.C.int;
390 Status : Cond_Value_Type;
396 Sleep_Time := To_OS_Time (Time, Mode);
398 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
399 or else Self_ID.Pending_Priority_Change
404 Self_ID.Common.LL.AST_Pending := True;
407 (Status, 0, Sleep_Time,
408 Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
410 if (Status and 1) /= 1 then
415 Result := pthread_cond_wait
416 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
419 Result := pthread_cond_wait
420 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
425 if not Self_ID.Common.LL.AST_Pending then
428 Sys_Cantim (Status, To_Address (Self_ID), 0);
429 pragma Assert ((Status and 1) = 1);
437 procedure Timed_Delay
440 Mode : ST.Delay_Modes)
442 Sleep_Time : OS_Time;
443 Result : Interfaces.C.int;
444 Status : Cond_Value_Type;
445 Yielded : Boolean := False;
448 -- Only the little window between deferring abort and
449 -- locking Self_ID is the reason we need to
450 -- check for pending abort and priority change below!
457 Write_Lock (Self_ID);
459 if Time /= 0.0 or else Mode /= Relative then
460 Sleep_Time := To_OS_Time (Time, Mode);
462 if Mode = Relative or else OS_Clock < Sleep_Time then
463 Self_ID.Common.State := Delay_Sleep;
464 Self_ID.Common.LL.AST_Pending := True;
467 (Status, 0, Sleep_Time,
468 Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
470 if (Status and 1) /= 1 then
475 if Self_ID.Pending_Priority_Change then
476 Self_ID.Pending_Priority_Change := False;
477 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
478 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
481 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
482 Sys_Cantim (Status, To_Address (Self_ID), 0);
483 pragma Assert ((Status and 1) = 1);
488 Result := pthread_cond_wait
489 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
491 Result := pthread_cond_wait
492 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
497 exit when not Self_ID.Common.LL.AST_Pending;
500 Self_ID.Common.State := Runnable;
511 Result := sched_yield;
514 SSL.Abort_Undefer.all;
517 ---------------------
518 -- Monotonic_Clock --
519 ---------------------
521 function Monotonic_Clock return Duration
522 renames System.OS_Primitives.Monotonic_Clock;
528 function RT_Resolution return Duration is
537 procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is
538 Result : Interfaces.C.int;
540 Result := pthread_cond_signal (T.Common.LL.CV'Access);
541 pragma Assert (Result = 0);
548 procedure Yield (Do_Yield : Boolean := True) is
549 Result : Interfaces.C.int;
552 Result := sched_yield;
560 procedure Set_Priority
562 Prio : System.Any_Priority;
563 Loss_Of_Inheritance : Boolean := False)
565 Result : Interfaces.C.int;
566 Param : aliased struct_sched_param;
568 T.Common.Current_Priority := Prio;
569 Param.sched_priority := Interfaces.C.int (Underlying_Priorities (Prio));
571 if Time_Slice_Val > 0 then
572 Result := pthread_setschedparam
573 (T.Common.LL.Thread, SCHED_RR, Param'Access);
575 elsif FIFO_Within_Priorities or else Time_Slice_Val = 0 then
576 Result := pthread_setschedparam
577 (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
580 Result := pthread_setschedparam
581 (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
584 pragma Assert (Result = 0);
591 function Get_Priority (T : Task_ID) return System.Any_Priority is
593 return T.Common.Current_Priority;
600 procedure Enter_Task (Self_ID : Task_ID) is
601 Result : Interfaces.C.int;
603 Self_ID.Common.LL.Thread := pthread_self;
605 -- It is not safe for the new task accept signals until it
606 -- has bound its TCB pointer to the thread with pthread_setspecific (),
607 -- since the handler wrappers use the TCB pointer
608 -- to restore the stack limit.
610 Result := pthread_setspecific (ATCB_Key, To_Address (Self_ID));
611 pragma Assert (Result = 0);
615 for J in Known_Tasks'Range loop
616 if Known_Tasks (J) = null then
617 Known_Tasks (J) := Self_ID;
618 Self_ID.Known_Tasks_Index := J;
630 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
632 return new Ada_Task_Control_Block (Entry_Num);
635 ----------------------
637 ----------------------
639 procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
640 Mutex_Attr : aliased pthread_mutexattr_t;
641 Result : Interfaces.C.int;
642 Cond_Attr : aliased pthread_condattr_t;
645 if not Single_Lock then
646 Result := pthread_mutexattr_init (Mutex_Attr'Access);
647 pragma Assert (Result = 0 or else Result = ENOMEM);
650 Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
652 pragma Assert (Result = 0 or else Result = ENOMEM);
660 Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
661 pragma Assert (Result = 0);
664 Result := pthread_condattr_init (Cond_Attr'Access);
665 pragma Assert (Result = 0 or else Result = ENOMEM);
668 Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
670 pragma Assert (Result = 0 or else Result = ENOMEM);
675 Self_ID.Common.LL.Exc_Stack_Ptr := new Exc_Stack_T;
676 SSL.Set_Exc_Stack_Addr
677 (To_Address (Self_ID),
678 Self_ID.Common.LL.Exc_Stack_Ptr (Exc_Stack_T'Last)'Address);
681 if not Single_Lock then
682 Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
683 pragma Assert (Result = 0);
689 Result := pthread_condattr_destroy (Cond_Attr'Access);
690 pragma Assert (Result = 0);
697 procedure Create_Task
699 Wrapper : System.Address;
700 Stack_Size : System.Parameters.Size_Type;
701 Priority : System.Any_Priority;
702 Succeeded : out Boolean)
704 Attributes : aliased pthread_attr_t;
705 Adjusted_Stack_Size : Interfaces.C.size_t;
706 Result : Interfaces.C.int;
708 function Thread_Body_Access is new
709 Unchecked_Conversion (System.Address, Thread_Body);
712 if Stack_Size = Unspecified_Size then
713 Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
715 elsif Stack_Size < Minimum_Stack_Size then
716 Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
719 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
722 -- Since the initial signal mask of a thread is inherited from the
723 -- creator, we need to set our local signal mask mask all signals
724 -- during the creation operation, to make sure the new thread is
725 -- not disturbed by signals before it has set its own Task_ID.
727 Result := pthread_attr_init (Attributes'Access);
728 pragma Assert (Result = 0 or else Result = ENOMEM);
735 Result := pthread_attr_setdetachstate
736 (Attributes'Access, PTHREAD_CREATE_DETACHED);
737 pragma Assert (Result = 0);
739 Result := pthread_attr_setstacksize
740 (Attributes'Access, Adjusted_Stack_Size);
741 pragma Assert (Result = 0);
743 -- This call may be unnecessary, not sure. ???
745 Result := pthread_attr_setinheritsched
746 (Attributes'Access, PTHREAD_EXPLICIT_SCHED);
747 pragma Assert (Result = 0);
749 Result := pthread_create
750 (T.Common.LL.Thread'Access,
752 Thread_Body_Access (Wrapper),
755 -- ENOMEM is a valid run-time error. Don't shut down.
757 pragma Assert (Result = 0
758 or else Result = EAGAIN or else Result = ENOMEM);
760 Succeeded := Result = 0;
762 Result := pthread_attr_destroy (Attributes'Access);
763 pragma Assert (Result = 0);
766 Set_Priority (T, Priority);
774 procedure Finalize_TCB (T : Task_ID) is
775 Result : Interfaces.C.int;
778 procedure Free is new
779 Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
781 procedure Free is new Unchecked_Deallocation
782 (Exc_Stack_T, Exc_Stack_Ptr_T);
785 if not Single_Lock then
786 Result := pthread_mutex_destroy (T.Common.LL.L'Access);
787 pragma Assert (Result = 0);
790 Result := pthread_cond_destroy (T.Common.LL.CV'Access);
791 pragma Assert (Result = 0);
793 if T.Known_Tasks_Index /= -1 then
794 Known_Tasks (T.Known_Tasks_Index) := null;
797 Free (T.Common.LL.Exc_Stack_Ptr);
805 procedure Exit_Task is
807 pthread_exit (System.Null_Address);
814 procedure Abort_Task (T : Task_ID) is
818 -- Why is this commented out ???
819 -- if T = Self and then T.Deferral_Level = 0
820 -- and then T.Pending_ATC_Level < T.ATC_Nesting_Level
822 -- raise Standard'Abort_Signal;
826 -- Interrupt Server_Tasks may be waiting on an event flag
828 if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
829 Wakeup (T, Interrupt_Server_Blocked_On_Event_Flag);
838 -- Dummy versions. The only currently working versions is for solaris
841 function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
850 function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
855 ----------------------
856 -- Environment_Task --
857 ----------------------
859 function Environment_Task return Task_ID is
861 return Environment_Task_ID;
862 end Environment_Task;
868 procedure Lock_RTS is
870 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
877 procedure Unlock_RTS is
879 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
886 function Suspend_Task
888 Thread_Self : Thread_Id) return Boolean is
899 Thread_Self : Thread_Id) return Boolean is
908 procedure Initialize (Environment_Task : Task_ID) is
910 Environment_Task_ID := Environment_Task;
912 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
913 -- Initialize the lock used to synchronize chain of all ATCBs.
915 Enter_Task (Environment_Task);
920 Result : Interfaces.C.int;
922 Result := pthread_key_create (ATCB_Key'Access, null);
923 pragma Assert (Result = 0);
925 end System.Task_Primitives.Operations;