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 HP-UX DCE threads 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.Interrupt_Management;
52 -- used for Keep_Unmasked
53 -- Abort_Task_Interrupt
56 with System.Interrupt_Management.Operations;
57 -- used for Set_Interrupt_Mask
59 pragma Elaborate_All (System.Interrupt_Management.Operations);
61 with System.Parameters;
64 with System.Task_Primitives.Interrupt_Operations;
65 -- used for Get_Interrupt_ID
68 -- used for Ada_Task_Control_Block
71 with System.Soft_Links;
72 -- used for Defer/Undefer_Abort
74 -- Note that we do not use System.Tasking.Initialization directly since
75 -- this is a higher level package that we shouldn't depend on. For example
76 -- when using the restricted run time, it is replaced by
77 -- System.Tasking.Restricted.Initialization
79 with System.OS_Primitives;
80 -- used for Delay_Modes
82 with Unchecked_Conversion;
83 with Unchecked_Deallocation;
85 package body System.Task_Primitives.Operations is
87 use System.Tasking.Debug;
90 use System.OS_Interface;
91 use System.Parameters;
92 use System.OS_Primitives;
94 package PIO renames System.Task_Primitives.Interrupt_Operations;
95 package SSL renames System.Soft_Links;
101 -- The followings are logically constants, but need to be initialized
104 ATCB_Key : aliased pthread_key_t;
105 -- Key used to find the Ada Task_ID associated with a thread
107 Single_RTS_Lock : aliased RTS_Lock;
108 -- This is a lock to allow only one thread of control in the RTS at
109 -- a time; it is used to execute in mutual exclusion from all other tasks.
110 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
112 Environment_Task_ID : Task_ID;
113 -- A variable to hold Task_ID for the environment task.
115 Unblocked_Signal_Mask : aliased sigset_t;
116 -- The set of signals that should unblocked in all tasks
118 Time_Slice_Val : Integer;
119 pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
121 Locking_Policy : Character;
122 pragma Import (C, Locking_Policy, "__gl_locking_policy");
124 Dispatching_Policy : Character;
125 pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
127 FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
128 -- Indicates whether FIFO_Within_Priorities is set.
130 -- The followings are internal configuration constants needed.
132 -----------------------
133 -- Local Subprograms --
134 -----------------------
136 procedure Abort_Handler (Sig : Signal);
138 function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
140 function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
146 procedure Abort_Handler (Sig : Signal) is
147 Self_Id : constant Task_ID := Self;
148 Result : Interfaces.C.int;
149 Old_Set : aliased sigset_t;
152 if Self_Id.Deferral_Level = 0
153 and then Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level and then
156 Self_Id.Aborting := True;
158 -- Make sure signals used for RTS internal purpose are unmasked
160 Result := pthread_sigmask (SIG_UNBLOCK,
161 Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
162 pragma Assert (Result = 0);
164 raise Standard'Abort_Signal;
172 -- The underlying thread system sets a guard page at the
173 -- bottom of a thread stack, so nothing is needed.
174 -- ??? Check the comment above
176 procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
185 function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
187 return T.Common.LL.Thread;
194 function Self return Task_ID is
195 Result : System.Address;
197 Result := pthread_getspecific (ATCB_Key);
198 pragma Assert (Result /= System.Null_Address);
199 return To_Task_ID (Result);
202 ---------------------
203 -- Initialize_Lock --
204 ---------------------
206 -- Note: mutexes and cond_variables needed per-task basis are
207 -- initialized in Initialize_TCB and the Storage_Error is
208 -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
209 -- used in RTS is initialized before any status change of RTS.
210 -- Therefore rasing Storage_Error in the following routines
211 -- should be able to be handled safely.
213 procedure Initialize_Lock
214 (Prio : System.Any_Priority;
217 Attributes : aliased pthread_mutexattr_t;
218 Result : Interfaces.C.int;
221 Result := pthread_mutexattr_init (Attributes'Access);
222 pragma Assert (Result = 0 or else Result = ENOMEM);
224 if Result = ENOMEM then
230 Result := pthread_mutex_init (L.L'Access, 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);
241 procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
242 Attributes : aliased pthread_mutexattr_t;
243 Result : Interfaces.C.int;
246 Result := pthread_mutexattr_init (Attributes'Access);
247 pragma Assert (Result = 0 or else Result = ENOMEM);
249 if Result = ENOMEM then
253 Result := pthread_mutex_init (L, Attributes'Access);
255 pragma Assert (Result = 0 or else Result = ENOMEM);
257 if Result = ENOMEM then
261 Result := pthread_mutexattr_destroy (Attributes'Access);
262 pragma Assert (Result = 0);
269 procedure Finalize_Lock (L : access Lock) is
270 Result : Interfaces.C.int;
272 Result := pthread_mutex_destroy (L.L'Access);
273 pragma Assert (Result = 0);
276 procedure Finalize_Lock (L : access RTS_Lock) is
277 Result : Interfaces.C.int;
279 Result := pthread_mutex_destroy (L);
280 pragma Assert (Result = 0);
287 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
288 Result : Interfaces.C.int;
290 L.Owner_Priority := Get_Priority (Self);
292 if L.Priority < L.Owner_Priority then
293 Ceiling_Violation := True;
297 Result := pthread_mutex_lock (L.L'Access);
298 pragma Assert (Result = 0);
299 Ceiling_Violation := False;
303 (L : access RTS_Lock; Global_Lock : Boolean := False)
305 Result : Interfaces.C.int;
307 if not Single_Lock or else Global_Lock then
308 Result := pthread_mutex_lock (L);
309 pragma Assert (Result = 0);
313 procedure Write_Lock (T : Task_ID) is
314 Result : Interfaces.C.int;
316 if not Single_Lock then
317 Result := pthread_mutex_lock (T.Common.LL.L'Access);
318 pragma Assert (Result = 0);
326 procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
328 Write_Lock (L, Ceiling_Violation);
335 procedure Unlock (L : access Lock) is
336 Result : Interfaces.C.int;
338 Result := pthread_mutex_unlock (L.L'Access);
339 pragma Assert (Result = 0);
342 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
343 Result : Interfaces.C.int;
345 if not Single_Lock or else Global_Lock then
346 Result := pthread_mutex_unlock (L);
347 pragma Assert (Result = 0);
351 procedure Unlock (T : Task_ID) is
352 Result : Interfaces.C.int;
354 if not Single_Lock then
355 Result := pthread_mutex_unlock (T.Common.LL.L'Access);
356 pragma Assert (Result = 0);
366 Reason : System.Tasking.Task_States)
368 Result : Interfaces.C.int;
371 Result := pthread_cond_wait
372 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
374 Result := pthread_cond_wait
375 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
378 -- EINTR is not considered a failure.
379 pragma Assert (Result = 0 or else Result = EINTR);
386 procedure Timed_Sleep
389 Mode : ST.Delay_Modes;
390 Reason : System.Tasking.Task_States;
391 Timedout : out Boolean;
392 Yielded : out Boolean)
394 Check_Time : constant Duration := Monotonic_Clock;
396 Request : aliased timespec;
397 Result : Interfaces.C.int;
403 if Mode = Relative then
404 Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
406 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
409 if Abs_Time > Check_Time then
410 Request := To_Timespec (Abs_Time);
413 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
414 or else Self_ID.Pending_Priority_Change;
417 Result := pthread_cond_timedwait
418 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
422 Result := pthread_cond_timedwait
423 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
427 exit when Abs_Time <= Monotonic_Clock;
429 if Result = 0 or Result = EINTR then
430 -- somebody may have called Wakeup for us
435 pragma Assert (Result = ETIMEDOUT);
444 procedure Timed_Delay
447 Mode : ST.Delay_Modes)
449 Check_Time : constant Duration := Monotonic_Clock;
451 Request : aliased timespec;
452 Result : Interfaces.C.int;
455 -- Only the little window between deferring abort and
456 -- locking Self_ID is the reason we need to
457 -- check for pending abort and priority change below! :(
465 Write_Lock (Self_ID);
467 if Mode = Relative then
468 Abs_Time := Time + Check_Time;
470 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
473 if Abs_Time > Check_Time then
474 Request := To_Timespec (Abs_Time);
475 Self_ID.Common.State := Delay_Sleep;
478 if Self_ID.Pending_Priority_Change then
479 Self_ID.Pending_Priority_Change := False;
480 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
481 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
484 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
487 Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
488 Single_RTS_Lock'Access, Request'Access);
490 Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
491 Self_ID.Common.LL.L'Access, Request'Access);
494 exit when Abs_Time <= Monotonic_Clock;
496 pragma Assert (Result = 0 or else
497 Result = ETIMEDOUT or else
501 Self_ID.Common.State := Runnable;
510 Result := sched_yield;
511 SSL.Abort_Undefer.all;
514 ---------------------
515 -- Monotonic_Clock --
516 ---------------------
518 function Monotonic_Clock return Duration is
519 TS : aliased timespec;
520 Result : Interfaces.C.int;
523 Result := Clock_Gettime (CLOCK_REALTIME, TS'Unchecked_Access);
524 pragma Assert (Result = 0);
525 return To_Duration (TS);
532 function RT_Resolution return Duration is
541 procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is
542 Result : Interfaces.C.int;
544 Result := pthread_cond_signal (T.Common.LL.CV'Access);
545 pragma Assert (Result = 0);
552 procedure Yield (Do_Yield : Boolean := True) is
553 Result : Interfaces.C.int;
556 Result := sched_yield;
564 type Prio_Array_Type is array (System.Any_Priority) of Integer;
565 pragma Atomic_Components (Prio_Array_Type);
567 Prio_Array : Prio_Array_Type;
568 -- Global array containing the id of the currently running task for
571 -- Note: we assume that we are on a single processor with run-til-blocked
574 procedure Set_Priority
576 Prio : System.Any_Priority;
577 Loss_Of_Inheritance : Boolean := False)
579 Result : Interfaces.C.int;
580 Array_Item : Integer;
581 Param : aliased struct_sched_param;
584 Param.sched_priority := Interfaces.C.int (Underlying_Priorities (Prio));
586 if Time_Slice_Val > 0 then
587 Result := pthread_setschedparam
588 (T.Common.LL.Thread, SCHED_RR, Param'Access);
590 elsif FIFO_Within_Priorities or else Time_Slice_Val = 0 then
591 Result := pthread_setschedparam
592 (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
595 Result := pthread_setschedparam
596 (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
599 pragma Assert (Result = 0);
601 if FIFO_Within_Priorities then
603 -- Annex D requirement [RM D.2.2 par. 9]:
604 -- If the task drops its priority due to the loss of inherited
605 -- priority, it is added at the head of the ready queue for its
606 -- new active priority.
608 if Loss_Of_Inheritance
609 and then Prio < T.Common.Current_Priority
611 Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
612 Prio_Array (T.Common.Base_Priority) := Array_Item;
615 -- Let some processes a chance to arrive
619 -- Then wait for our turn to proceed
621 exit when Array_Item = Prio_Array (T.Common.Base_Priority)
622 or else Prio_Array (T.Common.Base_Priority) = 1;
625 Prio_Array (T.Common.Base_Priority) :=
626 Prio_Array (T.Common.Base_Priority) - 1;
630 T.Common.Current_Priority := Prio;
637 function Get_Priority (T : Task_ID) return System.Any_Priority is
639 return T.Common.Current_Priority;
646 procedure Enter_Task (Self_ID : Task_ID) is
647 Result : Interfaces.C.int;
650 Self_ID.Common.LL.Thread := pthread_self;
652 Result := pthread_setspecific (ATCB_Key, To_Address (Self_ID));
653 pragma Assert (Result = 0);
657 for J in Known_Tasks'Range loop
658 if Known_Tasks (J) = null then
659 Known_Tasks (J) := Self_ID;
660 Self_ID.Known_Tasks_Index := J;
672 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
674 return new Ada_Task_Control_Block (Entry_Num);
681 procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
682 Mutex_Attr : aliased pthread_mutexattr_t;
683 Result : Interfaces.C.int;
684 Cond_Attr : aliased pthread_condattr_t;
687 if not Single_Lock then
688 Result := pthread_mutexattr_init (Mutex_Attr'Access);
689 pragma Assert (Result = 0 or else Result = ENOMEM);
692 Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
694 pragma Assert (Result = 0 or else Result = ENOMEM);
702 Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
703 pragma Assert (Result = 0);
706 Result := pthread_condattr_init (Cond_Attr'Access);
707 pragma Assert (Result = 0 or else Result = ENOMEM);
710 Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
712 pragma Assert (Result = 0 or else Result = ENOMEM);
718 if not Single_Lock then
719 Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
720 pragma Assert (Result = 0);
726 Result := pthread_condattr_destroy (Cond_Attr'Access);
727 pragma Assert (Result = 0);
734 procedure Create_Task
736 Wrapper : System.Address;
737 Stack_Size : System.Parameters.Size_Type;
738 Priority : System.Any_Priority;
739 Succeeded : out Boolean)
741 Attributes : aliased pthread_attr_t;
742 Adjusted_Stack_Size : Interfaces.C.size_t;
743 Result : Interfaces.C.int;
745 function Thread_Body_Access is new
746 Unchecked_Conversion (System.Address, Thread_Body);
749 if Stack_Size = Unspecified_Size then
750 Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
752 elsif Stack_Size < Minimum_Stack_Size then
753 Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
756 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
759 Result := pthread_attr_init (Attributes'Access);
760 pragma Assert (Result = 0 or else Result = ENOMEM);
767 Result := pthread_attr_setstacksize
768 (Attributes'Access, Adjusted_Stack_Size);
769 pragma Assert (Result = 0);
771 -- Since the initial signal mask of a thread is inherited from the
772 -- creator, and the Environment task has all its signals masked, we
773 -- do not need to manipulate caller's signal mask at this point.
774 -- All tasks in RTS will have All_Tasks_Mask initially.
776 Result := pthread_create
777 (T.Common.LL.Thread'Access,
779 Thread_Body_Access (Wrapper),
781 pragma Assert (Result = 0 or else Result = EAGAIN);
783 Succeeded := Result = 0;
785 pthread_detach (T.Common.LL.Thread'Access);
786 -- Detach the thread using pthread_detach, sinc DCE threads do not have
787 -- pthread_attr_set_detachstate.
789 Result := pthread_attr_destroy (Attributes'Access);
790 pragma Assert (Result = 0);
792 Set_Priority (T, Priority);
799 procedure Finalize_TCB (T : Task_ID) is
800 Result : Interfaces.C.int;
803 procedure Free is new
804 Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
807 if not Single_Lock then
808 Result := pthread_mutex_destroy (T.Common.LL.L'Access);
809 pragma Assert (Result = 0);
812 Result := pthread_cond_destroy (T.Common.LL.CV'Access);
813 pragma Assert (Result = 0);
815 if T.Known_Tasks_Index /= -1 then
816 Known_Tasks (T.Known_Tasks_Index) := null;
826 procedure Exit_Task is
828 pthread_exit (System.Null_Address);
835 procedure Abort_Task (T : Task_ID) is
838 -- Interrupt Server_Tasks may be waiting on an "event" flag (signal)
840 if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
841 System.Interrupt_Management.Operations.Interrupt_Self_Process
842 (System.Interrupt_Management.Interrupt_ID
843 (PIO.Get_Interrupt_ID (T)));
851 -- Dummy versions. The only currently working versions is for solaris
854 function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
863 function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
868 ----------------------
869 -- Environment_Task --
870 ----------------------
872 function Environment_Task return Task_ID is
874 return Environment_Task_ID;
875 end Environment_Task;
881 procedure Lock_RTS is
883 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
890 procedure Unlock_RTS is
892 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
899 function Suspend_Task
901 Thread_Self : Thread_Id) return Boolean is
912 Thread_Self : Thread_Id) return Boolean is
921 procedure Initialize (Environment_Task : Task_ID) is
922 act : aliased struct_sigaction;
923 old_act : aliased struct_sigaction;
924 Tmp_Set : aliased sigset_t;
925 Result : Interfaces.C.int;
929 Environment_Task_ID := Environment_Task;
931 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
932 -- Initialize the lock used to synchronize chain of all ATCBs.
934 Enter_Task (Environment_Task);
936 -- Install the abort-signal handler
939 act.sa_handler := Abort_Handler'Address;
941 Result := sigemptyset (Tmp_Set'Access);
942 pragma Assert (Result = 0);
943 act.sa_mask := Tmp_Set;
947 Signal (System.Interrupt_Management.Abort_Task_Interrupt),
948 act'Unchecked_Access,
949 old_act'Unchecked_Access);
950 pragma Assert (Result = 0);
953 procedure do_nothing (arg : System.Address);
955 procedure do_nothing (arg : System.Address) is
962 Result : Interfaces.C.int;
964 -- NOTE: Unlike other pthread implementations, we do *not* mask all
965 -- signals here since we handle signals using the process-wide primitive
966 -- signal, rather than using sigthreadmask and sigwait. The reason of
967 -- this difference is that sigwait doesn't work when some critical
968 -- signals (SIGABRT, SIGPIPE) are masked.
970 Result := pthread_key_create (ATCB_Key'Access, do_nothing'Access);
971 pragma Assert (Result = 0);
973 end System.Task_Primitives.Operations;