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) 1992-2004, 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. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 -- This is a Solaris (native) 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
47 -- used for Raise_Exception
50 -- used for String_Access, Getenv
56 with System.Interrupt_Management;
57 -- used for Keep_Unmasked
58 -- Abort_Task_Interrupt
61 with System.Interrupt_Management.Operations;
62 -- used for Set_Interrupt_Mask
64 pragma Elaborate_All (System.Interrupt_Management.Operations);
66 with System.Parameters;
70 -- used for Ada_Task_Control_Block
72 -- ATCB components and types
74 with System.Task_Info;
75 -- to initialize Task_Info for a C thread, in function Self
77 with System.Soft_Links;
78 -- used for Defer/Undefer_Abort
79 -- to initialize TSD for a C thread, in function Self
81 -- Note that we do not use System.Tasking.Initialization directly since
82 -- this is a higher level package that we shouldn't depend on. For example
83 -- when using the restricted run time, it is replaced by
84 -- System.Tasking.Restricted.Stages.
86 with System.OS_Primitives;
87 -- used for Delay_Modes
89 with Unchecked_Deallocation;
91 package body System.Task_Primitives.Operations is
93 use System.Tasking.Debug;
96 use System.OS_Interface;
97 use System.Parameters;
99 use System.OS_Primitives;
101 package SSL renames System.Soft_Links;
107 -- The following are logically constants, but need to be initialized
110 Environment_Task_Id : Task_Id;
111 -- A variable to hold Task_Id for the environment task.
112 -- If we use this variable to get the Task_Id, we need the following
113 -- ATCB_Key only for non-Ada threads.
115 Unblocked_Signal_Mask : aliased sigset_t;
116 -- The set of signals that should unblocked in all tasks
118 ATCB_Key : aliased thread_key_t;
119 -- Key used to find the Ada Task_Id associated with a thread,
120 -- at least for C threads unknown to the Ada run-time system.
122 Single_RTS_Lock : aliased RTS_Lock;
123 -- This is a lock to allow only one thread of control in the RTS at
124 -- a time; it is used to execute in mutual exclusion from all other tasks.
125 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
127 Next_Serial_Number : Task_Serial_Number := 100;
128 -- We start at 100, to reserve some special values for
129 -- using in error checking.
130 -- The following are internal configuration constants needed.
132 ----------------------
133 -- Priority Support --
134 ----------------------
136 Priority_Ceiling_Emulation : constant Boolean := True;
137 -- controls whether we emulate priority ceiling locking
139 -- To get a scheduling close to annex D requirements, we use the real-time
140 -- class provided for LWP's and map each task/thread to a specific and
141 -- unique LWP (there is 1 thread per LWP, and 1 LWP per thread).
143 -- The real time class can only be set when the process has root
144 -- priviledges, so in the other cases, we use the normal thread scheduling
145 -- and priority handling.
147 Using_Real_Time_Class : Boolean := False;
148 -- indicates wether the real time class is being used (i.e the process
149 -- has root priviledges).
151 Prio_Param : aliased struct_pcparms;
152 -- Hold priority info (Real_Time) initialized during the package
155 -----------------------------------
156 -- External Configuration Values --
157 -----------------------------------
159 Time_Slice_Val : Interfaces.C.long;
160 pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
162 Locking_Policy : Character;
163 pragma Import (C, Locking_Policy, "__gl_locking_policy");
165 Dispatching_Policy : Character;
166 pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
168 Foreign_Task_Elaborated : aliased Boolean := True;
169 -- Used to identified fake tasks (i.e., non-Ada Threads).
171 -----------------------
172 -- Local Subprograms --
173 -----------------------
175 function sysconf (name : System.OS_Interface.int) return processorid_t;
176 pragma Import (C, sysconf, "sysconf");
178 SC_NPROCESSORS_CONF : constant System.OS_Interface.int := 14;
181 (name : System.OS_Interface.int := SC_NPROCESSORS_CONF)
182 return processorid_t renames sysconf;
184 procedure Abort_Handler
186 Code : access siginfo_t;
187 Context : access ucontext_t);
188 -- Target-dependent binding of inter-thread Abort signal to
189 -- the raising of the Abort_Signal exception.
190 -- See also comments in 7staprop.adb
196 function Check_Initialize_Lock
198 Level : Lock_Level) return Boolean;
199 pragma Inline (Check_Initialize_Lock);
201 function Check_Lock (L : Lock_Ptr) return Boolean;
202 pragma Inline (Check_Lock);
204 function Record_Lock (L : Lock_Ptr) return Boolean;
205 pragma Inline (Record_Lock);
207 function Check_Sleep (Reason : Task_States) return Boolean;
208 pragma Inline (Check_Sleep);
210 function Record_Wakeup
212 Reason : Task_States) return Boolean;
213 pragma Inline (Record_Wakeup);
215 function Check_Wakeup
217 Reason : Task_States) return Boolean;
218 pragma Inline (Check_Wakeup);
220 function Check_Unlock (L : Lock_Ptr) return Boolean;
221 pragma Inline (Check_Unlock);
223 function Check_Finalize_Lock (L : Lock_Ptr) return Boolean;
224 pragma Inline (Check_Finalize_Lock);
232 procedure Initialize (Environment_Task : Task_Id);
233 pragma Inline (Initialize);
234 -- Initialize various data needed by this package.
236 function Is_Valid_Task return Boolean;
237 pragma Inline (Is_Valid_Task);
238 -- Does executing thread have a TCB?
240 procedure Set (Self_Id : Task_Id);
242 -- Set the self id for the current task.
244 function Self return Task_Id;
245 pragma Inline (Self);
246 -- Return a pointer to the Ada Task Control Block of the calling task.
250 package body Specific is separate;
251 -- The body of this package is target specific.
253 ---------------------------------
254 -- Support for foreign threads --
255 ---------------------------------
257 function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
258 -- Allocate and Initialize a new ATCB for the current Thread.
260 function Register_Foreign_Thread
261 (Thread : Thread_Id) return Task_Id is separate;
267 Check_Count : Integer := 0;
268 Lock_Count : Integer := 0;
269 Unlock_Count : Integer := 0;
275 procedure Abort_Handler
277 Code : access siginfo_t;
278 Context : access ucontext_t)
280 pragma Unreferenced (Sig);
281 pragma Unreferenced (Code);
282 pragma Unreferenced (Context);
284 Self_ID : constant Task_Id := Self;
285 Old_Set : aliased sigset_t;
287 Result : Interfaces.C.int;
288 pragma Unreferenced (Result);
291 -- It is not safe to raise an exception when using ZCX and the GCC
292 -- exception handling mechanism.
294 if ZCX_By_Default and then GCC_ZCX_Support then
298 if Self_ID.Deferral_Level = 0
299 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
300 and then not Self_ID.Aborting
302 Self_ID.Aborting := True;
304 -- Make sure signals used for RTS internal purpose are unmasked
306 Result := thr_sigsetmask (SIG_UNBLOCK,
307 Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
308 pragma Assert (Result = 0);
310 raise Standard'Abort_Signal;
318 -- The underlying thread system sets a guard page at the
319 -- bottom of a thread stack, so nothing is needed.
321 procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
322 pragma Unreferenced (T);
323 pragma Unreferenced (On);
332 function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
334 return T.Common.LL.Thread;
341 procedure Initialize (Environment_Task : ST.Task_Id) is
342 act : aliased struct_sigaction;
343 old_act : aliased struct_sigaction;
344 Tmp_Set : aliased sigset_t;
345 Result : Interfaces.C.int;
347 procedure Configure_Processors;
348 -- Processors configuration
349 -- The user can specify a processor which the program should run
350 -- on to emulate a single-processor system. This can be easily
351 -- done by setting environment variable GNAT_PROCESSOR to one of
354 -- -2 : use the default configuration (run the program on all
355 -- available processors) - this is the same as having
356 -- GNAT_PROCESSOR unset
357 -- -1 : let the RTS choose one processor and run the program on
359 -- 0 .. Last_Proc : run the program on the specified processor
361 -- Last_Proc is equal to the value of the system variable
362 -- _SC_NPROCESSORS_CONF, minus one.
364 procedure Configure_Processors is
365 Proc_Acc : constant GNAT.OS_Lib.String_Access :=
366 GNAT.OS_Lib.Getenv ("GNAT_PROCESSOR");
367 Proc : aliased processorid_t; -- User processor #
368 Last_Proc : processorid_t; -- Last processor #
371 if Proc_Acc.all'Length /= 0 then
372 -- Environment variable is defined
374 Last_Proc := Num_Procs - 1;
376 if Last_Proc /= -1 then
377 Proc := processorid_t'Value (Proc_Acc.all);
379 if Proc <= -2 or else Proc > Last_Proc then
380 -- Use the default configuration
383 -- Choose a processor
387 while Proc < Last_Proc loop
389 Result := p_online (Proc, PR_STATUS);
390 exit when Result = PR_ONLINE;
393 pragma Assert (Result = PR_ONLINE);
394 Result := processor_bind (P_PID, P_MYID, Proc, null);
395 pragma Assert (Result = 0);
398 -- Use user processor
400 Result := processor_bind (P_PID, P_MYID, Proc, null);
401 pragma Assert (Result = 0);
407 when Constraint_Error =>
409 -- Illegal environment variable GNAT_PROCESSOR - ignored
412 end Configure_Processors;
415 (Int : System.Interrupt_Management.Interrupt_ID) return Character;
416 pragma Import (C, State, "__gnat_get_interrupt_state");
417 -- Get interrupt state. Defined in a-init.c
418 -- The input argument is the interrupt number,
419 -- and the result is one of the following:
421 Default : constant Character := 's';
422 -- 'n' this interrupt not set by any Interrupt_State pragma
423 -- 'u' Interrupt_State pragma set state to User
424 -- 'r' Interrupt_State pragma set state to Runtime
425 -- 's' Interrupt_State pragma set state to System (use "default"
428 -- Start of processing for Initialize
431 Environment_Task_Id := Environment_Task;
433 -- This is done in Enter_Task, but this is too late for the
434 -- Environment Task, since we need to call Self in Check_Locks when
435 -- the run time is compiled with assertions on.
437 Specific.Initialize (Environment_Task);
439 -- Initialize the lock used to synchronize chain of all ATCBs.
441 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
443 Enter_Task (Environment_Task);
445 -- Install the abort-signal handler
447 if State (System.Interrupt_Management.Abort_Task_Interrupt)
450 -- Set sa_flags to SA_NODEFER so that during the handler execution
451 -- we do not change the Signal_Mask to be masked for the Abort_Signal
452 -- This is a temporary fix to the problem that the Signal_Mask is
453 -- not restored after the exception (longjmp) from the handler.
454 -- The right fix should be made in sigsetjmp so that we save
455 -- the Signal_Set and restore it after a longjmp.
456 -- In that case, this field should be changed back to 0. ???
460 act.sa_handler := Abort_Handler'Address;
461 Result := sigemptyset (Tmp_Set'Access);
462 pragma Assert (Result = 0);
463 act.sa_mask := Tmp_Set;
467 Signal (System.Interrupt_Management.Abort_Task_Interrupt),
468 act'Unchecked_Access,
469 old_act'Unchecked_Access);
470 pragma Assert (Result = 0);
473 Configure_Processors;
476 ---------------------
477 -- Initialize_Lock --
478 ---------------------
480 -- Note: mutexes and cond_variables needed per-task basis are
481 -- initialized in Initialize_TCB and the Storage_Error is
482 -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
483 -- used in RTS is initialized before any status change of RTS.
484 -- Therefore rasing Storage_Error in the following routines
485 -- should be able to be handled safely.
487 procedure Initialize_Lock
488 (Prio : System.Any_Priority;
491 Result : Interfaces.C.int;
494 pragma Assert (Check_Initialize_Lock (Lock_Ptr (L), PO_Level));
496 if Priority_Ceiling_Emulation then
500 Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address);
501 pragma Assert (Result = 0 or else Result = ENOMEM);
503 if Result = ENOMEM then
504 Raise_Exception (Storage_Error'Identity, "Failed to allocate a lock");
508 procedure Initialize_Lock
509 (L : access RTS_Lock;
512 Result : Interfaces.C.int;
515 pragma Assert (Check_Initialize_Lock
516 (To_Lock_Ptr (RTS_Lock_Ptr (L)), Level));
517 Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address);
518 pragma Assert (Result = 0 or else Result = ENOMEM);
520 if Result = ENOMEM then
521 Raise_Exception (Storage_Error'Identity, "Failed to allocate a lock");
529 procedure Finalize_Lock (L : access Lock) is
530 Result : Interfaces.C.int;
533 pragma Assert (Check_Finalize_Lock (Lock_Ptr (L)));
534 Result := mutex_destroy (L.L'Access);
535 pragma Assert (Result = 0);
538 procedure Finalize_Lock (L : access RTS_Lock) is
539 Result : Interfaces.C.int;
542 pragma Assert (Check_Finalize_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
543 Result := mutex_destroy (L.L'Access);
544 pragma Assert (Result = 0);
551 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
552 Result : Interfaces.C.int;
555 pragma Assert (Check_Lock (Lock_Ptr (L)));
557 if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then
559 Self_Id : constant Task_Id := Self;
560 Saved_Priority : System.Any_Priority;
563 if Self_Id.Common.LL.Active_Priority > L.Ceiling then
564 Ceiling_Violation := True;
568 Saved_Priority := Self_Id.Common.LL.Active_Priority;
570 if Self_Id.Common.LL.Active_Priority < L.Ceiling then
571 Set_Priority (Self_Id, L.Ceiling);
574 Result := mutex_lock (L.L'Access);
575 pragma Assert (Result = 0);
576 Ceiling_Violation := False;
578 L.Saved_Priority := Saved_Priority;
582 Result := mutex_lock (L.L'Access);
583 pragma Assert (Result = 0);
584 Ceiling_Violation := False;
587 pragma Assert (Record_Lock (Lock_Ptr (L)));
591 (L : access RTS_Lock;
592 Global_Lock : Boolean := False)
594 Result : Interfaces.C.int;
597 if not Single_Lock or else Global_Lock then
598 pragma Assert (Check_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
599 Result := mutex_lock (L.L'Access);
600 pragma Assert (Result = 0);
601 pragma Assert (Record_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
605 procedure Write_Lock (T : Task_Id) is
606 Result : Interfaces.C.int;
609 if not Single_Lock then
610 pragma Assert (Check_Lock (To_Lock_Ptr (T.Common.LL.L'Access)));
611 Result := mutex_lock (T.Common.LL.L.L'Access);
612 pragma Assert (Result = 0);
613 pragma Assert (Record_Lock (To_Lock_Ptr (T.Common.LL.L'Access)));
621 procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
623 Write_Lock (L, Ceiling_Violation);
630 procedure Unlock (L : access Lock) is
631 Result : Interfaces.C.int;
634 pragma Assert (Check_Unlock (Lock_Ptr (L)));
636 if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then
638 Self_Id : constant Task_Id := Self;
641 Result := mutex_unlock (L.L'Access);
642 pragma Assert (Result = 0);
644 if Self_Id.Common.LL.Active_Priority > L.Saved_Priority then
645 Set_Priority (Self_Id, L.Saved_Priority);
649 Result := mutex_unlock (L.L'Access);
650 pragma Assert (Result = 0);
654 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
655 Result : Interfaces.C.int;
658 if not Single_Lock or else Global_Lock then
659 pragma Assert (Check_Unlock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
660 Result := mutex_unlock (L.L'Access);
661 pragma Assert (Result = 0);
665 procedure Unlock (T : Task_Id) is
666 Result : Interfaces.C.int;
669 if not Single_Lock then
670 pragma Assert (Check_Unlock (To_Lock_Ptr (T.Common.LL.L'Access)));
671 Result := mutex_unlock (T.Common.LL.L.L'Access);
672 pragma Assert (Result = 0);
676 -- For the time delay implementation, we need to make sure we
677 -- achieve following criteria:
679 -- 1) We have to delay at least for the amount requested.
680 -- 2) We have to give up CPU even though the actual delay does not
681 -- result in blocking.
682 -- 3) Except for restricted run-time systems that do not support
683 -- ATC or task abort, the delay must be interrupted by the
684 -- abort_task operation.
685 -- 4) The implementation has to be efficient so that the delay overhead
686 -- is relatively cheap.
687 -- (1)-(3) are Ada requirements. Even though (2) is an Annex-D
688 -- requirement we still want to provide the effect in all cases.
689 -- The reason is that users may want to use short delays to implement
690 -- their own scheduling effect in the absence of language provided
691 -- scheduling policies.
693 ---------------------
694 -- Monotonic_Clock --
695 ---------------------
697 function Monotonic_Clock return Duration is
698 TS : aliased timespec;
699 Result : Interfaces.C.int;
701 Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
702 pragma Assert (Result = 0);
703 return To_Duration (TS);
710 function RT_Resolution return Duration is
719 procedure Yield (Do_Yield : Boolean := True) is
722 System.OS_Interface.thr_yield;
730 function Self return Task_Id renames Specific.Self;
736 procedure Set_Priority
738 Prio : System.Any_Priority;
739 Loss_Of_Inheritance : Boolean := False)
741 pragma Unreferenced (Loss_Of_Inheritance);
743 Result : Interfaces.C.int;
744 pragma Unreferenced (Result);
746 Param : aliased struct_pcparms;
751 T.Common.Current_Priority := Prio;
753 if Priority_Ceiling_Emulation then
754 T.Common.LL.Active_Priority := Prio;
757 if Using_Real_Time_Class then
758 Param.pc_cid := Prio_Param.pc_cid;
759 Param.rt_pri := pri_t (Prio);
760 Param.rt_tqsecs := Prio_Param.rt_tqsecs;
761 Param.rt_tqnsecs := Prio_Param.rt_tqnsecs;
763 Result := Interfaces.C.int (
764 priocntl (PC_VERSION, P_LWPID, T.Common.LL.LWP, PC_SETPARMS,
768 if T.Common.Task_Info /= null
769 and then not T.Common.Task_Info.Bound_To_LWP
771 -- The task is not bound to a LWP, so use thr_setprio
774 thr_setprio (T.Common.LL.Thread, Interfaces.C.int (Prio));
778 -- The task is bound to a LWP, use priocntl
790 function Get_Priority (T : Task_Id) return System.Any_Priority is
792 return T.Common.Current_Priority;
799 procedure Enter_Task (Self_ID : Task_Id) is
800 Result : Interfaces.C.int;
801 Proc : processorid_t; -- User processor #
802 Last_Proc : processorid_t; -- Last processor #
804 use System.Task_Info;
806 Self_ID.Common.LL.Thread := thr_self;
808 Self_ID.Common.LL.LWP := lwp_self;
810 if Self_ID.Common.Task_Info /= null then
811 if Self_ID.Common.Task_Info.New_LWP
812 and then Self_ID.Common.Task_Info.CPU /= CPU_UNCHANGED
814 Last_Proc := Num_Procs - 1;
816 if Self_ID.Common.Task_Info.CPU = ANY_CPU then
820 while Proc < Last_Proc loop
821 Result := p_online (Proc, PR_STATUS);
822 exit when Result = PR_ONLINE;
826 Result := processor_bind (P_LWPID, P_MYID, Proc, null);
827 pragma Assert (Result = 0);
830 -- Use specified processor
832 if Self_ID.Common.Task_Info.CPU < 0
833 or else Self_ID.Common.Task_Info.CPU > Last_Proc
835 raise Invalid_CPU_Number;
838 Result := processor_bind
839 (P_LWPID, P_MYID, Self_ID.Common.Task_Info.CPU, null);
840 pragma Assert (Result = 0);
845 Specific.Set (Self_ID);
847 -- We need the above code even if we do direct fetch of Task_Id in Self
848 -- for the main task on Sun, x86 Solaris and for gcc 2.7.2.
852 for J in Known_Tasks'Range loop
853 if Known_Tasks (J) = null then
854 Known_Tasks (J) := Self_ID;
855 Self_ID.Known_Tasks_Index := J;
867 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
869 return new Ada_Task_Control_Block (Entry_Num);
876 function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
878 -----------------------------
879 -- Register_Foreign_Thread --
880 -----------------------------
882 function Register_Foreign_Thread return Task_Id is
884 if Is_Valid_Task then
887 return Register_Foreign_Thread (thr_self);
889 end Register_Foreign_Thread;
895 procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
896 Result : Interfaces.C.int := 0;
899 -- Give the task a unique serial number.
901 Self_ID.Serial_Number := Next_Serial_Number;
902 Next_Serial_Number := Next_Serial_Number + 1;
903 pragma Assert (Next_Serial_Number /= 0);
905 Self_ID.Common.LL.Thread := To_thread_t (-1);
907 if not Single_Lock then
909 (Self_ID.Common.LL.L.L'Access, USYNC_THREAD, System.Null_Address);
910 Self_ID.Common.LL.L.Level :=
911 Private_Task_Serial_Number (Self_ID.Serial_Number);
912 pragma Assert (Result = 0 or else Result = ENOMEM);
916 Result := cond_init (Self_ID.Common.LL.CV'Access, USYNC_THREAD, 0);
917 pragma Assert (Result = 0 or else Result = ENOMEM);
923 if not Single_Lock then
924 Result := mutex_destroy (Self_ID.Common.LL.L.L'Access);
925 pragma Assert (Result = 0);
936 procedure Create_Task
938 Wrapper : System.Address;
939 Stack_Size : System.Parameters.Size_Type;
940 Priority : System.Any_Priority;
941 Succeeded : out Boolean)
943 pragma Unreferenced (Priority);
945 Result : Interfaces.C.int;
946 Adjusted_Stack_Size : Interfaces.C.size_t;
947 Opts : Interfaces.C.int := THR_DETACHED;
949 Page_Size : constant System.Parameters.Size_Type := 4096;
950 -- This constant is for reserving extra space at the
951 -- end of the stack, which can be used by the stack
952 -- checking as guard page. The idea is that we need
953 -- to have at least Stack_Size bytes available for
956 use System.Task_Info;
959 if Stack_Size = System.Parameters.Unspecified_Size then
960 Adjusted_Stack_Size :=
961 Interfaces.C.size_t (Default_Stack_Size + Page_Size);
963 elsif Stack_Size < Minimum_Stack_Size then
964 Adjusted_Stack_Size :=
965 Interfaces.C.size_t (Minimum_Stack_Size + Page_Size);
968 Adjusted_Stack_Size :=
969 Interfaces.C.size_t (Stack_Size + Page_Size);
972 -- Since the initial signal mask of a thread is inherited from the
973 -- creator, and the Environment task has all its signals masked, we
974 -- do not need to manipulate caller's signal mask at this point.
975 -- All tasks in RTS will have All_Tasks_Mask initially.
977 if T.Common.Task_Info /= null then
978 if T.Common.Task_Info.New_LWP then
979 Opts := Opts + THR_NEW_LWP;
982 if T.Common.Task_Info.Bound_To_LWP then
983 Opts := Opts + THR_BOUND;
987 Opts := THR_DETACHED + THR_BOUND;
991 (System.Null_Address,
993 Thread_Body_Access (Wrapper),
996 T.Common.LL.Thread'Access);
998 Succeeded := Result = 0;
1001 or else Result = ENOMEM
1002 or else Result = EAGAIN);
1009 procedure Finalize_TCB (T : Task_Id) is
1010 Result : Interfaces.C.int;
1012 Is_Self : constant Boolean := T = Self;
1014 procedure Free is new
1015 Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
1018 T.Common.LL.Thread := To_thread_t (0);
1020 if not Single_Lock then
1021 Result := mutex_destroy (T.Common.LL.L.L'Access);
1022 pragma Assert (Result = 0);
1025 Result := cond_destroy (T.Common.LL.CV'Access);
1026 pragma Assert (Result = 0);
1028 if T.Known_Tasks_Index /= -1 then
1029 Known_Tasks (T.Known_Tasks_Index) := null;
1035 Specific.Set (null);
1043 -- This procedure must be called with abort deferred.
1044 -- It can no longer call Self or access
1045 -- the current task's ATCB, since the ATCB has been deallocated.
1047 procedure Exit_Task is
1049 Specific.Set (null);
1056 procedure Abort_Task (T : Task_Id) is
1057 Result : Interfaces.C.int;
1059 pragma Assert (T /= Self);
1061 Result := thr_kill (T.Common.LL.Thread,
1062 Signal (System.Interrupt_Management.Abort_Task_Interrupt));
1065 pragma Assert (Result = 0);
1074 Reason : Task_States)
1076 Result : Interfaces.C.int;
1079 pragma Assert (Check_Sleep (Reason));
1081 if Dynamic_Priority_Support
1082 and then Self_ID.Pending_Priority_Change
1084 Self_ID.Pending_Priority_Change := False;
1085 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
1086 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
1091 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access);
1094 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access);
1097 pragma Assert (Record_Wakeup
1098 (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1099 pragma Assert (Result = 0 or else Result = EINTR);
1102 -- Note that we are relying heaviliy here on the GNAT feature
1103 -- that Calendar.Time, System.Real_Time.Time, Duration, and
1104 -- System.Real_Time.Time_Span are all represented in the same
1105 -- way, i.e., as a 64-bit count of nanoseconds.
1107 -- This allows us to always pass the timeout value as a Duration.
1110 -- We are taking liberties here with the semantics of the delays.
1111 -- That is, we make no distinction between delays on the Calendar clock
1112 -- and delays on the Real_Time clock. That is technically incorrect, if
1113 -- the Calendar clock happens to be reset or adjusted.
1114 -- To solve this defect will require modification to the compiler
1115 -- interface, so that it can pass through more information, to tell
1116 -- us here which clock to use!
1118 -- cond_timedwait will return if any of the following happens:
1119 -- 1) some other task did cond_signal on this condition variable
1120 -- In this case, the return value is 0
1121 -- 2) the call just returned, for no good reason
1122 -- This is called a "spurious wakeup".
1123 -- In this case, the return value may also be 0.
1124 -- 3) the time delay expires
1125 -- In this case, the return value is ETIME
1126 -- 4) this task received a signal, which was handled by some
1127 -- handler procedure, and now the thread is resuming execution
1128 -- UNIX calls this an "interrupted" system call.
1129 -- In this case, the return value is EINTR
1131 -- If the cond_timedwait returns 0 or EINTR, it is still
1132 -- possible that the time has actually expired, and by chance
1133 -- a signal or cond_signal occurred at around the same time.
1135 -- We have also observed that on some OS's the value ETIME
1136 -- will be returned, but the clock will show that the full delay
1137 -- has not yet expired.
1139 -- For these reasons, we need to check the clock after return
1140 -- from cond_timedwait. If the time has expired, we will set
1143 -- This check might be omitted for systems on which the
1144 -- cond_timedwait() never returns early or wakes up spuriously.
1146 -- Annex D requires that completion of a delay cause the task
1147 -- to go to the end of its priority queue, regardless of whether
1148 -- the task actually was suspended by the delay. Since
1149 -- cond_timedwait does not do this on Solaris, we add a call
1150 -- to thr_yield at the end. We might do this at the beginning,
1151 -- instead, but then the round-robin effect would not be the
1152 -- same; the delayed task would be ahead of other tasks of the
1153 -- same priority that awoke while it was sleeping.
1155 -- For Timed_Sleep, we are expecting possible cond_signals
1156 -- to indicate other events (e.g., completion of a RV or
1157 -- completion of the abortable part of an async. select),
1158 -- we want to always return if interrupted. The caller will
1159 -- be responsible for checking the task state to see whether
1160 -- the wakeup was spurious, and to go back to sleep again
1161 -- in that case. We don't need to check for pending abort
1162 -- or priority change on the way in our out; that is the
1163 -- caller's responsibility.
1165 -- For Timed_Delay, we are not expecting any cond_signals or
1166 -- other interruptions, except for priority changes and aborts.
1167 -- Therefore, we don't want to return unless the delay has
1168 -- actually expired, or the call has been aborted. In this
1169 -- case, since we want to implement the entire delay statement
1170 -- semantics, we do need to check for pending abort and priority
1171 -- changes. We can quietly handle priority changes inside the
1172 -- procedure, since there is no entry-queue reordering involved.
1178 procedure Timed_Sleep
1181 Mode : ST.Delay_Modes;
1182 Reason : System.Tasking.Task_States;
1183 Timedout : out Boolean;
1184 Yielded : out Boolean)
1186 Check_Time : constant Duration := Monotonic_Clock;
1187 Abs_Time : Duration;
1188 Request : aliased timespec;
1189 Result : Interfaces.C.int;
1192 pragma Assert (Check_Sleep (Reason));
1196 if Mode = Relative then
1197 Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
1199 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
1202 if Abs_Time > Check_Time then
1203 Request := To_Timespec (Abs_Time);
1206 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
1207 or else (Dynamic_Priority_Support and then
1208 Self_ID.Pending_Priority_Change);
1211 Result := cond_timedwait (Self_ID.Common.LL.CV'Access,
1212 Single_RTS_Lock.L'Access, Request'Access);
1214 Result := cond_timedwait (Self_ID.Common.LL.CV'Access,
1215 Self_ID.Common.LL.L.L'Access, Request'Access);
1220 exit when Abs_Time <= Monotonic_Clock;
1222 if Result = 0 or Result = EINTR then
1224 -- Somebody may have called Wakeup for us
1230 pragma Assert (Result = ETIME);
1234 pragma Assert (Record_Wakeup
1235 (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1242 procedure Timed_Delay
1245 Mode : ST.Delay_Modes)
1247 Check_Time : constant Duration := Monotonic_Clock;
1248 Abs_Time : Duration;
1249 Request : aliased timespec;
1250 Result : Interfaces.C.int;
1251 Yielded : Boolean := False;
1254 -- Only the little window between deferring abort and
1255 -- locking Self_ID is the reason we need to
1256 -- check for pending abort and priority change below!
1258 SSL.Abort_Defer.all;
1264 Write_Lock (Self_ID);
1266 if Mode = Relative then
1267 Abs_Time := Time + Check_Time;
1269 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
1272 if Abs_Time > Check_Time then
1273 Request := To_Timespec (Abs_Time);
1274 Self_ID.Common.State := Delay_Sleep;
1276 pragma Assert (Check_Sleep (Delay_Sleep));
1279 if Dynamic_Priority_Support and then
1280 Self_ID.Pending_Priority_Change then
1281 Self_ID.Pending_Priority_Change := False;
1282 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
1283 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
1286 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
1289 Result := cond_timedwait (Self_ID.Common.LL.CV'Access,
1290 Single_RTS_Lock.L'Access, Request'Access);
1292 Result := cond_timedwait (Self_ID.Common.LL.CV'Access,
1293 Self_ID.Common.LL.L.L'Access, Request'Access);
1298 exit when Abs_Time <= Monotonic_Clock;
1300 pragma Assert (Result = 0 or else
1301 Result = ETIME or else
1305 pragma Assert (Record_Wakeup
1306 (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Delay_Sleep));
1308 Self_ID.Common.State := Runnable;
1321 SSL.Abort_Undefer.all;
1330 Reason : Task_States)
1332 Result : Interfaces.C.int;
1335 pragma Assert (Check_Wakeup (T, Reason));
1336 Result := cond_signal (T.Common.LL.CV'Access);
1337 pragma Assert (Result = 0);
1340 ---------------------------
1341 -- Check_Initialize_Lock --
1342 ---------------------------
1344 -- The following code is intended to check some of the invariant
1345 -- assertions related to lock usage, on which we depend.
1347 function Check_Initialize_Lock
1349 Level : Lock_Level) return Boolean
1351 Self_ID : constant Task_Id := Self;
1354 -- Check that caller is abort-deferred
1356 if Self_ID.Deferral_Level <= 0 then
1360 -- Check that the lock is not yet initialized
1362 if L.Level /= 0 then
1366 L.Level := Lock_Level'Pos (Level) + 1;
1368 end Check_Initialize_Lock;
1374 function Check_Lock (L : Lock_Ptr) return Boolean is
1375 Self_ID : constant Task_Id := Self;
1379 -- Check that the argument is not null
1385 -- Check that L is not frozen
1391 -- Check that caller is abort-deferred
1393 if Self_ID.Deferral_Level <= 0 then
1397 -- Check that caller is not holding this lock already
1399 if L.Owner = To_Owner_ID (To_Address (Self_ID)) then
1407 -- Check that TCB lock order rules are satisfied
1409 P := Self_ID.Common.LL.Locks;
1411 if P.Level >= L.Level
1412 and then (P.Level > 2 or else L.Level > 2)
1425 function Record_Lock (L : Lock_Ptr) return Boolean is
1426 Self_ID : constant Task_Id := Self;
1430 Lock_Count := Lock_Count + 1;
1432 -- There should be no owner for this lock at this point
1434 if L.Owner /= null then
1440 L.Owner := To_Owner_ID (To_Address (Self_ID));
1446 -- Check that TCB lock order rules are satisfied
1448 P := Self_ID.Common.LL.Locks;
1454 Self_ID.Common.LL.Locking := null;
1455 Self_ID.Common.LL.Locks := L;
1463 function Check_Sleep (Reason : Task_States) return Boolean is
1464 pragma Unreferenced (Reason);
1466 Self_ID : constant Task_Id := Self;
1470 -- Check that caller is abort-deferred
1472 if Self_ID.Deferral_Level <= 0 then
1480 -- Check that caller is holding own lock, on top of list
1482 if Self_ID.Common.LL.Locks /=
1483 To_Lock_Ptr (Self_ID.Common.LL.L'Access)
1488 -- Check that TCB lock order rules are satisfied
1490 if Self_ID.Common.LL.Locks.Next /= null then
1494 Self_ID.Common.LL.L.Owner := null;
1495 P := Self_ID.Common.LL.Locks;
1496 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1505 function Record_Wakeup
1507 Reason : Task_States) return Boolean
1509 pragma Unreferenced (Reason);
1511 Self_ID : constant Task_Id := Self;
1517 L.Owner := To_Owner_ID (To_Address (Self_ID));
1523 -- Check that TCB lock order rules are satisfied
1525 P := Self_ID.Common.LL.Locks;
1531 Self_ID.Common.LL.Locking := null;
1532 Self_ID.Common.LL.Locks := L;
1540 function Check_Wakeup
1542 Reason : Task_States) return Boolean
1544 Self_ID : constant Task_Id := Self;
1547 -- Is caller holding T's lock?
1549 if T.Common.LL.L.Owner /= To_Owner_ID (To_Address (Self_ID)) then
1553 -- Are reasons for wakeup and sleep consistent?
1555 if T.Common.State /= Reason then
1566 function Check_Unlock (L : Lock_Ptr) return Boolean is
1567 Self_ID : constant Task_Id := Self;
1571 Unlock_Count := Unlock_Count + 1;
1577 if L.Buddy /= null then
1582 Check_Count := Unlock_Count;
1585 if Unlock_Count - Check_Count > 1000 then
1586 Check_Count := Unlock_Count;
1589 -- Check that caller is abort-deferred
1591 if Self_ID.Deferral_Level <= 0 then
1595 -- Check that caller is holding this lock, on top of list
1597 if Self_ID.Common.LL.Locks /= L then
1601 -- Record there is no owner now
1604 P := Self_ID.Common.LL.Locks;
1605 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1610 --------------------
1611 -- Check_Finalize --
1612 --------------------
1614 function Check_Finalize_Lock (L : Lock_Ptr) return Boolean is
1615 Self_ID : constant Task_Id := Self;
1618 -- Check that caller is abort-deferred
1620 if Self_ID.Deferral_Level <= 0 then
1624 -- Check that no one is holding this lock
1626 if L.Owner /= null then
1632 end Check_Finalize_Lock;
1638 function Check_Exit (Self_ID : Task_Id) return Boolean is
1640 -- Check that caller is just holding Global_Task_Lock
1641 -- and no other locks
1643 if Self_ID.Common.LL.Locks = null then
1647 -- 2 = Global_Task_Level
1649 if Self_ID.Common.LL.Locks.Level /= 2 then
1653 if Self_ID.Common.LL.Locks.Next /= null then
1657 -- Check that caller is abort-deferred
1659 if Self_ID.Deferral_Level <= 0 then
1666 --------------------
1667 -- Check_No_Locks --
1668 --------------------
1670 function Check_No_Locks (Self_ID : Task_Id) return Boolean is
1672 return Self_ID.Common.LL.Locks = null;
1675 ----------------------
1676 -- Environment_Task --
1677 ----------------------
1679 function Environment_Task return Task_Id is
1681 return Environment_Task_Id;
1682 end Environment_Task;
1688 procedure Lock_RTS is
1690 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1697 procedure Unlock_RTS is
1699 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1706 function Suspend_Task
1708 Thread_Self : Thread_Id) return Boolean
1711 if T.Common.LL.Thread /= Thread_Self then
1712 return thr_suspend (T.Common.LL.Thread) = 0;
1722 function Resume_Task
1724 Thread_Self : Thread_Id) return Boolean
1727 if T.Common.LL.Thread /= Thread_Self then
1728 return thr_continue (T.Common.LL.Thread) = 0;
1734 -- Package elaboration
1738 Result : Interfaces.C.int;
1741 -- Mask Environment task for all signals. The original mask of the
1742 -- Environment task will be recovered by Interrupt_Server task
1743 -- during the elaboration of s-interr.adb.
1745 System.Interrupt_Management.Operations.Set_Interrupt_Mask
1746 (System.Interrupt_Management.Operations.All_Tasks_Mask'Access);
1748 -- Prepare the set of signals that should unblocked in all tasks
1750 Result := sigemptyset (Unblocked_Signal_Mask'Access);
1751 pragma Assert (Result = 0);
1753 for J in Interrupt_Management.Interrupt_ID loop
1754 if System.Interrupt_Management.Keep_Unmasked (J) then
1755 Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1756 pragma Assert (Result = 0);
1760 -- We need the following code to support automatic creation of fake
1761 -- ATCB's for C threads that call the Ada run-time system, even if
1762 -- we use a faster way of getting Self for real Ada tasks.
1764 Result := thr_keycreate (ATCB_Key'Access, System.Null_Address);
1765 pragma Assert (Result = 0);
1768 if Dispatching_Policy = 'F' then
1770 Result : Interfaces.C.long;
1771 Class_Info : aliased struct_pcinfo;
1772 Secs, Nsecs : Interfaces.C.long;
1775 -- If a pragma Time_Slice is specified, takes the value in account.
1777 if Time_Slice_Val > 0 then
1778 -- Convert Time_Slice_Val (microseconds) into seconds and
1781 Secs := Time_Slice_Val / 1_000_000;
1782 Nsecs := (Time_Slice_Val rem 1_000_000) * 1_000;
1784 -- Otherwise, default to no time slicing (i.e run until blocked)
1791 -- Get the real time class id.
1793 Class_Info.pc_clname (1) := 'R';
1794 Class_Info.pc_clname (2) := 'T';
1795 Class_Info.pc_clname (3) := ASCII.NUL;
1797 Result := priocntl (PC_VERSION, P_LWPID, P_MYID, PC_GETCID,
1798 Class_Info'Address);
1800 -- Request the real time class
1802 Prio_Param.pc_cid := Class_Info.pc_cid;
1803 Prio_Param.rt_pri := pri_t (Class_Info.rt_maxpri);
1804 Prio_Param.rt_tqsecs := Secs;
1805 Prio_Param.rt_tqnsecs := Nsecs;
1807 Result := priocntl (PC_VERSION, P_LWPID, P_MYID, PC_SETPARMS,
1808 Prio_Param'Address);
1810 Using_Real_Time_Class := Result /= -1;
1813 end System.Task_Primitives.Operations;