1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . T A S K I N G . I N I T I A L I Z A T I O N -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2021, Free Software Foundation, Inc. -- 10-- -- 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 3, or (at your option) any later ver- -- 14-- sion. GNAT 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. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32pragma Style_Checks (All_Checks); 33-- Turn off subprogram alpha ordering check, since we group soft link bodies 34-- and dummy soft link bodies together separately in this unit. 35 36with System.Task_Primitives; 37with System.Task_Primitives.Operations; 38with System.Soft_Links; 39with System.Soft_Links.Tasking; 40with System.Tasking.Debug; 41with System.Tasking.Task_Attributes; 42 43with System.Secondary_Stack; 44pragma Elaborate_All (System.Secondary_Stack); 45pragma Unreferenced (System.Secondary_Stack); 46-- Make sure the body of Secondary_Stack is elaborated before calling 47-- Init_Tasking_Soft_Links. See comments for this routine for explanation. 48 49package body System.Tasking.Initialization is 50 51 package STPO renames System.Task_Primitives.Operations; 52 package SSL renames System.Soft_Links; 53 54 use Parameters; 55 use Task_Primitives.Operations; 56 57 Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock; 58 -- This is a global lock; it is used to execute in mutual exclusion from 59 -- all other tasks. It is only used by Task_Lock, Task_Unlock, and 60 -- Final_Task_Unlock. 61 62 ---------------------------------------------------------------------- 63 -- Tasking versions of some services needed by non-tasking programs -- 64 ---------------------------------------------------------------------- 65 66 procedure Abort_Defer; 67 -- NON-INLINE versions without Self_ID for soft links 68 69 procedure Abort_Undefer; 70 -- NON-INLINE versions without Self_ID for soft links 71 72 procedure Task_Lock; 73 -- Locks out other tasks. Preceding a section of code by Task_Lock and 74 -- following it by Task_Unlock creates a critical region. This is used 75 -- for ensuring that a region of non-tasking code (such as code used to 76 -- allocate memory) is tasking safe. Note that it is valid for calls to 77 -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e. 78 -- only the corresponding outer level Task_Unlock will actually unlock. 79 80 procedure Task_Unlock; 81 -- Releases lock previously set by call to Task_Lock. In the nested case, 82 -- all nested locks must be released before other tasks competing for the 83 -- tasking lock are released. 84 85 function Get_Current_Excep return SSL.EOA; 86 -- Task-safe version of SSL.Get_Current_Excep 87 88 function Task_Name return String; 89 -- Returns current task's name 90 91 ------------------------ 92 -- Local Subprograms -- 93 ------------------------ 94 95 ---------------------------- 96 -- Tasking Initialization -- 97 ---------------------------- 98 99 procedure Init_RTS; 100 -- This procedure completes the initialization of the GNARL. The first part 101 -- of the initialization is done in the body of System.Tasking. It consists 102 -- of initializing global locks, and installing tasking versions of certain 103 -- operations used by the compiler. Init_RTS is called during elaboration. 104 105 -------------------------- 106 -- Change_Base_Priority -- 107 -------------------------- 108 109 -- Call only with abort deferred and holding Self_ID locked 110 111 procedure Change_Base_Priority (T : Task_Id) is 112 begin 113 if T.Common.Base_Priority /= T.New_Base_Priority then 114 T.Common.Base_Priority := T.New_Base_Priority; 115 Set_Priority (T, T.Common.Base_Priority); 116 end if; 117 end Change_Base_Priority; 118 119 ------------------------ 120 -- Check_Abort_Status -- 121 ------------------------ 122 123 function Check_Abort_Status return Integer is 124 Self_ID : constant Task_Id := Self; 125 begin 126 if Self_ID /= null 127 and then Self_ID.Deferral_Level = 0 128 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level 129 and then not Self_ID.Aborting 130 then 131 return 1; 132 else 133 return 0; 134 end if; 135 end Check_Abort_Status; 136 137 ----------------- 138 -- Defer_Abort -- 139 ----------------- 140 141 procedure Defer_Abort (Self_ID : Task_Id) is 142 begin 143 if No_Abort then 144 return; 145 end if; 146 147 pragma Assert (Self_ID.Deferral_Level = 0); 148 149 -- pragma Assert 150 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level); 151 152 -- The above check has been useful in detecting mismatched defer/undefer 153 -- pairs. You may uncomment it when testing on systems that support 154 -- preemptive abort. 155 156 -- If the OS supports preemptive abort (e.g. pthread_kill), it should 157 -- have happened already. A problem is with systems that do not support 158 -- preemptive abort, and so rely on polling. On such systems we may get 159 -- false failures of the assertion, since polling for pending abort does 160 -- no occur until the abort undefer operation. 161 162 -- Even on systems that only poll for abort, the assertion may be useful 163 -- for catching missed abort completion polling points. The operations 164 -- that undefer abort poll for pending aborts. This covers most of the 165 -- places where the core Ada semantics require abort to be caught, 166 -- without any special attention. However, this generally happens on 167 -- exit from runtime system call, which means a pending abort will not 168 -- be noticed on the way into the runtime system. We considered adding a 169 -- check for pending aborts at this point, but chose not to, because of 170 -- the overhead. Instead, we searched for RTS calls where abort 171 -- completion is required and a task could go farther than Ada allows 172 -- before undeferring abort; we then modified the code to ensure the 173 -- abort would be detected. 174 175 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 176 end Defer_Abort; 177 178 -------------------------- 179 -- Defer_Abort_Nestable -- 180 -------------------------- 181 182 procedure Defer_Abort_Nestable (Self_ID : Task_Id) is 183 begin 184 if No_Abort then 185 return; 186 end if; 187 188 -- The following assertion is by default disabled. See the comment in 189 -- Defer_Abort on the situations in which it may be useful to uncomment 190 -- this assertion and enable the test. 191 192 -- pragma Assert 193 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else 194 -- Self_ID.Deferral_Level > 0); 195 196 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 197 end Defer_Abort_Nestable; 198 199 ----------------- 200 -- Abort_Defer -- 201 ----------------- 202 203 procedure Abort_Defer is 204 Self_ID : Task_Id; 205 begin 206 if No_Abort then 207 return; 208 end if; 209 210 Self_ID := STPO.Self; 211 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 212 end Abort_Defer; 213 214 ----------------------- 215 -- Get_Current_Excep -- 216 ----------------------- 217 218 function Get_Current_Excep return SSL.EOA is 219 begin 220 return STPO.Self.Common.Compiler_Data.Current_Excep'Access; 221 end Get_Current_Excep; 222 223 ----------------------- 224 -- Do_Pending_Action -- 225 ----------------------- 226 227 -- Call only when holding no locks 228 229 procedure Do_Pending_Action (Self_ID : Task_Id) is 230 231 begin 232 pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0); 233 234 -- Needs loop to recheck for pending action in case a new one occurred 235 -- while we had abort deferred below. 236 237 loop 238 -- Temporarily defer abort so that we can lock Self_ID 239 240 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 241 242 Write_Lock (Self_ID); 243 Self_ID.Pending_Action := False; 244 Unlock (Self_ID); 245 246 -- Restore the original Deferral value 247 248 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 249 250 if not Self_ID.Pending_Action then 251 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then 252 if not Self_ID.Aborting then 253 Self_ID.Aborting := True; 254 pragma Debug 255 (Debug.Trace (Self_ID, "raise Abort_Signal", 'B')); 256 raise Standard'Abort_Signal; 257 258 pragma Assert (not Self_ID.ATC_Hack); 259 260 elsif Self_ID.ATC_Hack then 261 262 -- The solution really belongs in the Abort_Signal handler 263 -- for async. entry calls. The present hack is very 264 -- fragile. It relies that the very next point after 265 -- Exit_One_ATC_Level at which the task becomes abortable 266 -- will be the call to Undefer_Abort in the 267 -- Abort_Signal handler. 268 269 Self_ID.ATC_Hack := False; 270 271 pragma Debug 272 (Debug.Trace 273 (Self_ID, "raise Abort_Signal (ATC hack)", 'B')); 274 raise Standard'Abort_Signal; 275 end if; 276 end if; 277 278 return; 279 end if; 280 end loop; 281 end Do_Pending_Action; 282 283 ----------------------- 284 -- Final_Task_Unlock -- 285 ----------------------- 286 287 -- This version is only for use in Terminate_Task, when the task is 288 -- relinquishing further rights to its own ATCB. 289 290 -- There is a very interesting potential race condition there, where the 291 -- old task may run concurrently with a new task that is allocated the old 292 -- tasks (now reused) ATCB. The critical thing here is to not make any 293 -- reference to the ATCB after the lock is released. See also comments on 294 -- Terminate_Task and Unlock. 295 296 procedure Final_Task_Unlock (Self_ID : Task_Id) is 297 begin 298 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting = 1); 299 Unlock (Global_Task_Lock'Access); 300 end Final_Task_Unlock; 301 302 -------------- 303 -- Init_RTS -- 304 -------------- 305 306 procedure Init_RTS is 307 Self_Id : Task_Id; 308 begin 309 Tasking.Initialize; 310 311 -- Terminate run time (regular vs restricted) specific initialization 312 -- of the environment task. 313 314 Self_Id := Environment_Task; 315 Self_Id.Master_Of_Task := Environment_Task_Level; 316 Self_Id.Master_Within := Self_Id.Master_Of_Task + 1; 317 318 for L in Self_Id.Entry_Calls'Range loop 319 Self_Id.Entry_Calls (L).Self := Self_Id; 320 Self_Id.Entry_Calls (L).Level := L; 321 end loop; 322 323 Self_Id.Awake_Count := 1; 324 Self_Id.Alive_Count := 1; 325 326 -- Normally, a task starts out with internal master nesting level one 327 -- larger than external master nesting level. It is incremented to one 328 -- by Enter_Master, which is called in the task body only if the 329 -- compiler thinks the task may have dependent tasks. There is no 330 -- corresponding call to Enter_Master for the environment task, so we 331 -- would need to increment it to 2 here. Instead, we set it to 3. By 332 -- doing this we reserve the level 2 for server tasks of the runtime 333 -- system. The environment task does not need to wait for these server 334 335 Self_Id.Master_Within := Library_Task_Level; 336 337 -- Initialize lock used to implement mutual exclusion between all tasks 338 339 Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level); 340 341 -- Notify that the tasking run time has been elaborated so that 342 -- the tasking version of the soft links can be used. 343 344 if not No_Abort then 345 SSL.Abort_Defer := Abort_Defer'Access; 346 SSL.Abort_Undefer := Abort_Undefer'Access; 347 end if; 348 349 SSL.Lock_Task := Task_Lock'Access; 350 SSL.Unlock_Task := Task_Unlock'Access; 351 SSL.Check_Abort_Status := Check_Abort_Status'Access; 352 SSL.Task_Name := Task_Name'Access; 353 SSL.Get_Current_Excep := Get_Current_Excep'Access; 354 355 -- Initialize the tasking soft links (if not done yet) that are common 356 -- to the full and the restricted run times. 357 358 SSL.Tasking.Init_Tasking_Soft_Links; 359 360 -- Abort is deferred in a new ATCB, so we need to undefer abort at this 361 -- stage to make the environment task abortable. 362 363 Undefer_Abort (Environment_Task); 364 end Init_RTS; 365 366 --------------------------- 367 -- Locked_Abort_To_Level-- 368 --------------------------- 369 370 -- Abort a task to the specified ATC nesting level. 371 -- Call this only with T locked. 372 373 -- An earlier version of this code contained a call to Wakeup. That should 374 -- not be necessary here, if Abort_Task is implemented correctly, since 375 -- Abort_Task should include the effect of Wakeup. However, the above call 376 -- was in earlier versions of this file, and at least for some targets 377 -- Abort_Task has not been doing Wakeup. It should not hurt to uncomment 378 -- the above call, until the error is corrected for all targets. 379 380 -- See extended comments in package body System.Tasking.Abort for the 381 -- overall design of the implementation of task abort. 382 -- ??? there is no such package ??? 383 384 -- If the task is sleeping it will be in an abort-deferred region, and will 385 -- not have Abort_Signal raised by Abort_Task. Such an "abort deferral" is 386 -- just to protect the RTS internals, and not necessarily required to 387 -- enforce Ada semantics. Abort_Task should wake the task up and let it 388 -- decide if it wants to complete the aborted construct immediately. 389 390 -- Note that the effect of the low-level Abort_Task is not persistent. 391 -- If the target task is not blocked, this wakeup will be missed. 392 393 -- We don't bother calling Abort_Task if this task is aborting itself, 394 -- since we are inside the RTS and have abort deferred. Similarly, We don't 395 -- bother to call Abort_Task if T is terminated, since there is no need to 396 -- abort a terminated task, and it could be dangerous to try if the task 397 -- has stopped executing. 398 399 -- Note that an earlier version of this code had some false reasoning about 400 -- being able to reliably wake up a task that had suspended on a blocking 401 -- system call that does not atomically release the task's lock (e.g., UNIX 402 -- nanosleep, which we once thought could be used to implement delays). 403 -- That still left the possibility of missed wakeups. 404 405 -- We cannot safely call Vulnerable_Complete_Activation here, since that 406 -- requires locking Self_ID.Parent. The anti-deadlock lock ordering rules 407 -- would then require us to release the lock on Self_ID first, which would 408 -- create a timing window for other tasks to lock Self_ID. This is 409 -- significant for tasks that may be aborted before their execution can 410 -- enter the task body, and so they do not get a chance to call 411 -- Complete_Task. The actual work for this case is done in Terminate_Task. 412 413 procedure Locked_Abort_To_Level 414 (Self_ID : Task_Id; 415 T : Task_Id; 416 L : ATC_Level_Base) 417 is 418 begin 419 if not T.Aborting and then T /= Self_ID then 420 case T.Common.State is 421 when Terminated 422 | Unactivated 423 => 424 pragma Assert (Standard.False); 425 null; 426 427 when Activating 428 | Runnable 429 => 430 if T.ATC_Nesting_Level > Level_No_ATC_Occurring then 431 -- This scenario occurs when an asynchronous protected entry 432 -- call is canceled during a requeue with abort. 433 434 T.Entry_Calls 435 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 436 end if; 437 438 when Interrupt_Server_Blocked_On_Event_Flag => 439 null; 440 441 when AST_Server_Sleep 442 | Async_Select_Sleep 443 | Delay_Sleep 444 | Interrupt_Server_Blocked_Interrupt_Sleep 445 | Interrupt_Server_Idle_Sleep 446 | Timer_Server_Sleep 447 => 448 Wakeup (T, T.Common.State); 449 450 when Acceptor_Delay_Sleep 451 | Acceptor_Sleep 452 => 453 T.Open_Accepts := null; 454 Wakeup (T, T.Common.State); 455 456 when Entry_Caller_Sleep => 457 pragma Assert (T.ATC_Nesting_Level > Level_No_ATC_Occurring); 458 459 T.Entry_Calls 460 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 461 Wakeup (T, T.Common.State); 462 463 when Activator_Sleep 464 | Asynchronous_Hold 465 | Master_Completion_Sleep 466 | Master_Phase_2_Sleep 467 => 468 null; 469 end case; 470 end if; 471 472 if T.Pending_ATC_Level > L then 473 T.Pending_ATC_Level := L; 474 T.Pending_Action := True; 475 476 if L = Level_Completed_Task then 477 T.Callable := False; 478 end if; 479 480 -- This prevents aborted task from accepting calls 481 482 if T.Aborting then 483 484 -- The test above is just a heuristic, to reduce wasteful 485 -- calls to Abort_Task. We are holding T locked, and this 486 -- value will not be set to False except with T also locked, 487 -- inside Exit_One_ATC_Level, so we should not miss wakeups. 488 489 if T.Common.State = Acceptor_Sleep 490 or else 491 T.Common.State = Acceptor_Delay_Sleep 492 then 493 T.Open_Accepts := null; 494 end if; 495 496 elsif T /= Self_ID and then 497 (T.Common.State = Runnable 498 or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag) 499 500 -- The task is blocked on a system call waiting for the 501 -- completion event. In this case Abort_Task may need to take 502 -- special action in order to succeed. 503 504 then 505 Abort_Task (T); 506 end if; 507 end if; 508 end Locked_Abort_To_Level; 509 510 -------------------------------- 511 -- Remove_From_All_Tasks_List -- 512 -------------------------------- 513 514 procedure Remove_From_All_Tasks_List (T : Task_Id) is 515 C : Task_Id; 516 Previous : Task_Id; 517 518 begin 519 pragma Debug 520 (Debug.Trace (Self, "Remove_From_All_Tasks_List", 'C')); 521 522 Previous := Null_Task; 523 C := All_Tasks_List; 524 while C /= Null_Task loop 525 if C = T then 526 if Previous = Null_Task then 527 All_Tasks_List := All_Tasks_List.Common.All_Tasks_Link; 528 else 529 Previous.Common.All_Tasks_Link := C.Common.All_Tasks_Link; 530 end if; 531 532 return; 533 end if; 534 535 Previous := C; 536 C := C.Common.All_Tasks_Link; 537 end loop; 538 539 pragma Assert (Standard.False); 540 end Remove_From_All_Tasks_List; 541 542 --------------- 543 -- Task_Lock -- 544 --------------- 545 546 procedure Task_Lock (Self_ID : Task_Id) is 547 begin 548 Self_ID.Common.Global_Task_Lock_Nesting := 549 Self_ID.Common.Global_Task_Lock_Nesting + 1; 550 551 if Self_ID.Common.Global_Task_Lock_Nesting = 1 then 552 Defer_Abort_Nestable (Self_ID); 553 Write_Lock (Global_Task_Lock'Access); 554 end if; 555 end Task_Lock; 556 557 procedure Task_Lock is 558 begin 559 Task_Lock (STPO.Self); 560 end Task_Lock; 561 562 --------------- 563 -- Task_Name -- 564 --------------- 565 566 function Task_Name return String is 567 Self_Id : constant Task_Id := STPO.Self; 568 begin 569 return Self_Id.Common.Task_Image (1 .. Self_Id.Common.Task_Image_Len); 570 end Task_Name; 571 572 ----------------- 573 -- Task_Unlock -- 574 ----------------- 575 576 procedure Task_Unlock (Self_ID : Task_Id) is 577 begin 578 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting > 0); 579 Self_ID.Common.Global_Task_Lock_Nesting := 580 Self_ID.Common.Global_Task_Lock_Nesting - 1; 581 582 if Self_ID.Common.Global_Task_Lock_Nesting = 0 then 583 Unlock (Global_Task_Lock'Access); 584 Undefer_Abort_Nestable (Self_ID); 585 end if; 586 end Task_Unlock; 587 588 procedure Task_Unlock is 589 begin 590 Task_Unlock (STPO.Self); 591 end Task_Unlock; 592 593 ------------------- 594 -- Undefer_Abort -- 595 ------------------- 596 597 -- Precondition : Self does not hold any locks 598 599 -- Undefer_Abort is called on any abort completion point (aka. 600 -- synchronization point). It performs the following actions if they 601 -- are pending: (1) change the base priority, (2) abort the task. 602 603 -- The priority change has to occur before abort. Otherwise, it would 604 -- take effect no earlier than the next abort completion point. 605 606 procedure Undefer_Abort (Self_ID : Task_Id) is 607 begin 608 if No_Abort then 609 return; 610 end if; 611 612 pragma Assert (Self_ID.Deferral_Level = 1); 613 614 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 615 616 if Self_ID.Deferral_Level = 0 then 617 pragma Assert (Check_No_Locks (Self_ID)); 618 619 if Self_ID.Pending_Action then 620 Do_Pending_Action (Self_ID); 621 end if; 622 end if; 623 end Undefer_Abort; 624 625 ---------------------------- 626 -- Undefer_Abort_Nestable -- 627 ---------------------------- 628 629 -- An earlier version would re-defer abort if an abort is in progress. 630 -- Then, we modified the effect of the raise statement so that it defers 631 -- abort until control reaches a handler. That was done to prevent 632 -- "skipping over" a handler if another asynchronous abort occurs during 633 -- the propagation of the abort to the handler. 634 635 -- There has been talk of reversing that decision, based on a newer 636 -- implementation of exception propagation. Care must be taken to evaluate 637 -- how such a change would interact with the above code and all the places 638 -- where abort-deferral is used to bridge over critical transitions, such 639 -- as entry to the scope of a region with a finalizer and entry into the 640 -- body of an accept-procedure. 641 642 procedure Undefer_Abort_Nestable (Self_ID : Task_Id) is 643 begin 644 if No_Abort then 645 return; 646 end if; 647 648 pragma Assert (Self_ID.Deferral_Level > 0); 649 650 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 651 652 if Self_ID.Deferral_Level = 0 then 653 654 pragma Assert (Check_No_Locks (Self_ID)); 655 656 if Self_ID.Pending_Action then 657 Do_Pending_Action (Self_ID); 658 end if; 659 end if; 660 end Undefer_Abort_Nestable; 661 662 ------------------- 663 -- Abort_Undefer -- 664 ------------------- 665 666 procedure Abort_Undefer is 667 Self_ID : Task_Id; 668 begin 669 if No_Abort then 670 return; 671 end if; 672 673 Self_ID := STPO.Self; 674 675 if Self_ID.Deferral_Level = 0 then 676 677 -- In case there are different views on whether Abort is supported 678 -- between the expander and the run time, we may end up with 679 -- Self_ID.Deferral_Level being equal to zero, when called from 680 -- the procedure created by the expander that corresponds to a 681 -- task body. In this case, there's nothing to be done. 682 683 -- See related code in System.Tasking.Stages.Create_Task resetting 684 -- Deferral_Level when System.Restrictions.Abort_Allowed is False. 685 686 return; 687 end if; 688 689 pragma Assert (Self_ID.Deferral_Level > 0); 690 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 691 692 if Self_ID.Deferral_Level = 0 then 693 pragma Assert (Check_No_Locks (Self_ID)); 694 695 if Self_ID.Pending_Action then 696 Do_Pending_Action (Self_ID); 697 end if; 698 end if; 699 end Abort_Undefer; 700 701 -------------------------- 702 -- Wakeup_Entry_Caller -- 703 -------------------------- 704 705 -- This is called at the end of service of an entry call, to abort the 706 -- caller if he is in an abortable part, and to wake up the caller if it 707 -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue. 708 709 -- (This enforces the rule that a task must be off-queue if its state is 710 -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self. 711 712 -- Timed_Call or Simple_Call: 713 -- The caller is waiting on Entry_Caller_Sleep, in 714 -- Wait_For_Completion, or Wait_For_Completion_With_Timeout. 715 716 -- Conditional_Call: 717 -- The caller might be in Wait_For_Completion, 718 -- waiting for a rendezvous (possibly requeued without abort) 719 -- to complete. 720 721 -- Asynchronous_Call: 722 -- The caller may be executing in the abortable part o 723 -- an async. select, or on a time delay, 724 -- if Entry_Call.State >= Was_Abortable. 725 726 procedure Wakeup_Entry_Caller 727 (Self_ID : Task_Id; 728 Entry_Call : Entry_Call_Link; 729 New_State : Entry_Call_State) 730 is 731 Caller : constant Task_Id := Entry_Call.Self; 732 733 begin 734 pragma Debug (Debug.Trace 735 (Self_ID, "Wakeup_Entry_Caller", 'E', Caller)); 736 pragma Assert (New_State = Done or else New_State = Cancelled); 737 738 pragma Assert (Caller.Common.State /= Unactivated); 739 740 Entry_Call.State := New_State; 741 742 if Entry_Call.Mode = Asynchronous_Call then 743 744 -- Abort the caller in his abortable part, but do so only if call has 745 -- been queued abortably. 746 747 if Entry_Call.State >= Was_Abortable or else New_State = Done then 748 Locked_Abort_To_Level (Self_ID, Caller, Entry_Call.Level - 1); 749 end if; 750 751 elsif Caller.Common.State = Entry_Caller_Sleep then 752 Wakeup (Caller, Entry_Caller_Sleep); 753 end if; 754 end Wakeup_Entry_Caller; 755 756 ------------------------- 757 -- Finalize_Attributes -- 758 ------------------------- 759 760 procedure Finalize_Attributes (T : Task_Id) is 761 Attr : Atomic_Address; 762 763 begin 764 for J in T.Attributes'Range loop 765 Attr := T.Attributes (J); 766 767 if Attr /= 0 and then Task_Attributes.Require_Finalization (J) then 768 Task_Attributes.To_Attribute (Attr).Free (Attr); 769 T.Attributes (J) := 0; 770 end if; 771 end loop; 772 end Finalize_Attributes; 773 774begin 775 Init_RTS; 776end System.Tasking.Initialization; 777