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) 1992-2014, 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 36pragma Polling (Off); 37-- Turn polling off for this package. We don't need polling during any of the 38-- routines in this package, and more to the point, if we try to poll it can 39-- cause infinite loops. 40 41with Ada.Exceptions; 42 43with System.Task_Primitives; 44with System.Task_Primitives.Operations; 45with System.Soft_Links; 46with System.Soft_Links.Tasking; 47with System.Tasking.Debug; 48with System.Tasking.Task_Attributes; 49with System.Parameters; 50 51with System.Secondary_Stack; 52pragma Elaborate_All (System.Secondary_Stack); 53pragma Unreferenced (System.Secondary_Stack); 54-- Make sure the body of Secondary_Stack is elaborated before calling 55-- Init_Tasking_Soft_Links. See comments for this routine for explanation. 56 57package body System.Tasking.Initialization is 58 59 package STPO renames System.Task_Primitives.Operations; 60 package SSL renames System.Soft_Links; 61 package AE renames Ada.Exceptions; 62 63 use Parameters; 64 use Task_Primitives.Operations; 65 66 Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock; 67 -- This is a global lock; it is used to execute in mutual exclusion from 68 -- all other tasks. It is only used by Task_Lock, Task_Unlock, and 69 -- Final_Task_Unlock. 70 71 ---------------------------------------------------------------------- 72 -- Tasking versions of some services needed by non-tasking programs -- 73 ---------------------------------------------------------------------- 74 75 procedure Abort_Defer; 76 -- NON-INLINE versions without Self_ID for soft links 77 78 procedure Abort_Undefer; 79 -- NON-INLINE versions without Self_ID for soft links 80 81 procedure Task_Lock; 82 -- Locks out other tasks. Preceding a section of code by Task_Lock and 83 -- following it by Task_Unlock creates a critical region. This is used 84 -- for ensuring that a region of non-tasking code (such as code used to 85 -- allocate memory) is tasking safe. Note that it is valid for calls to 86 -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e. 87 -- only the corresponding outer level Task_Unlock will actually unlock. 88 89 procedure Task_Unlock; 90 -- Releases lock previously set by call to Task_Lock. In the nested case, 91 -- all nested locks must be released before other tasks competing for the 92 -- tasking lock are released. 93 94 function Get_Current_Excep return SSL.EOA; 95 -- Task-safe version of SSL.Get_Current_Excep 96 97 procedure Update_Exception 98 (X : AE.Exception_Occurrence := SSL.Current_Target_Exception); 99 -- Handle exception setting and check for pending actions 100 101 function Task_Name return String; 102 -- Returns current task's name 103 104 ------------------------ 105 -- Local Subprograms -- 106 ------------------------ 107 108 ---------------------------- 109 -- Tasking Initialization -- 110 ---------------------------- 111 112 procedure Init_RTS; 113 -- This procedure completes the initialization of the GNARL. The first part 114 -- of the initialization is done in the body of System.Tasking. It consists 115 -- of initializing global locks, and installing tasking versions of certain 116 -- operations used by the compiler. Init_RTS is called during elaboration. 117 118 -------------------------- 119 -- Change_Base_Priority -- 120 -------------------------- 121 122 -- Call only with abort deferred and holding Self_ID locked 123 124 procedure Change_Base_Priority (T : Task_Id) is 125 begin 126 if T.Common.Base_Priority /= T.New_Base_Priority then 127 T.Common.Base_Priority := T.New_Base_Priority; 128 Set_Priority (T, T.Common.Base_Priority); 129 end if; 130 end Change_Base_Priority; 131 132 ------------------------ 133 -- Check_Abort_Status -- 134 ------------------------ 135 136 function Check_Abort_Status return Integer is 137 Self_ID : constant Task_Id := Self; 138 begin 139 if Self_ID /= null 140 and then Self_ID.Deferral_Level = 0 141 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level 142 then 143 return 1; 144 else 145 return 0; 146 end if; 147 end Check_Abort_Status; 148 149 ----------------- 150 -- Defer_Abort -- 151 ----------------- 152 153 procedure Defer_Abort (Self_ID : Task_Id) is 154 begin 155 if No_Abort then 156 return; 157 end if; 158 159 pragma Assert (Self_ID.Deferral_Level = 0); 160 161 -- pragma Assert 162 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level); 163 164 -- The above check has been useful in detecting mismatched defer/undefer 165 -- pairs. You may uncomment it when testing on systems that support 166 -- preemptive abort. 167 168 -- If the OS supports preemptive abort (e.g. pthread_kill), it should 169 -- have happened already. A problem is with systems that do not support 170 -- preemptive abort, and so rely on polling. On such systems we may get 171 -- false failures of the assertion, since polling for pending abort does 172 -- no occur until the abort undefer operation. 173 174 -- Even on systems that only poll for abort, the assertion may be useful 175 -- for catching missed abort completion polling points. The operations 176 -- that undefer abort poll for pending aborts. This covers most of the 177 -- places where the core Ada semantics require abort to be caught, 178 -- without any special attention. However, this generally happens on 179 -- exit from runtime system call, which means a pending abort will not 180 -- be noticed on the way into the runtime system. We considered adding a 181 -- check for pending aborts at this point, but chose not to, because of 182 -- the overhead. Instead, we searched for RTS calls where abort 183 -- completion is required and a task could go farther than Ada allows 184 -- before undeferring abort; we then modified the code to ensure the 185 -- abort would be detected. 186 187 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 188 end Defer_Abort; 189 190 -------------------------- 191 -- Defer_Abort_Nestable -- 192 -------------------------- 193 194 procedure Defer_Abort_Nestable (Self_ID : Task_Id) is 195 begin 196 if No_Abort then 197 return; 198 end if; 199 200 -- The following assertion is by default disabled. See the comment in 201 -- Defer_Abort on the situations in which it may be useful to uncomment 202 -- this assertion and enable the test. 203 204 -- pragma Assert 205 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else 206 -- Self_ID.Deferral_Level > 0); 207 208 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 209 end Defer_Abort_Nestable; 210 211 ----------------- 212 -- Abort_Defer -- 213 ----------------- 214 215 procedure Abort_Defer is 216 Self_ID : Task_Id; 217 begin 218 if No_Abort then 219 return; 220 end if; 221 222 Self_ID := STPO.Self; 223 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 224 end Abort_Defer; 225 226 ----------------------- 227 -- Get_Current_Excep -- 228 ----------------------- 229 230 function Get_Current_Excep return SSL.EOA is 231 begin 232 return STPO.Self.Common.Compiler_Data.Current_Excep'Access; 233 end Get_Current_Excep; 234 235 ----------------------- 236 -- Do_Pending_Action -- 237 ----------------------- 238 239 -- Call only when holding no locks 240 241 procedure Do_Pending_Action (Self_ID : Task_Id) is 242 use type Ada.Exceptions.Exception_Id; 243 244 begin 245 pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0); 246 247 -- Needs loop to recheck for pending action in case a new one occurred 248 -- while we had abort deferred below. 249 250 loop 251 -- Temporarily defer abort so that we can lock Self_ID 252 253 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 254 255 if Single_Lock then 256 Lock_RTS; 257 end if; 258 259 Write_Lock (Self_ID); 260 Self_ID.Pending_Action := False; 261 Unlock (Self_ID); 262 263 if Single_Lock then 264 Unlock_RTS; 265 end if; 266 267 -- Restore the original Deferral value 268 269 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 270 271 if not Self_ID.Pending_Action then 272 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then 273 if not Self_ID.Aborting then 274 Self_ID.Aborting := True; 275 pragma Debug 276 (Debug.Trace (Self_ID, "raise Abort_Signal", 'B')); 277 raise Standard'Abort_Signal; 278 279 pragma Assert (not Self_ID.ATC_Hack); 280 281 elsif Self_ID.ATC_Hack then 282 283 -- The solution really belongs in the Abort_Signal handler 284 -- for async. entry calls. The present hack is very 285 -- fragile. It relies that the very next point after 286 -- Exit_One_ATC_Level at which the task becomes abortable 287 -- will be the call to Undefer_Abort in the 288 -- Abort_Signal handler. 289 290 Self_ID.ATC_Hack := False; 291 292 pragma Debug 293 (Debug.Trace 294 (Self_ID, "raise Abort_Signal (ATC hack)", 'B')); 295 raise Standard'Abort_Signal; 296 end if; 297 end if; 298 299 return; 300 end if; 301 end loop; 302 end Do_Pending_Action; 303 304 ----------------------- 305 -- Final_Task_Unlock -- 306 ----------------------- 307 308 -- This version is only for use in Terminate_Task, when the task is 309 -- relinquishing further rights to its own ATCB. 310 311 -- There is a very interesting potential race condition there, where the 312 -- old task may run concurrently with a new task that is allocated the old 313 -- tasks (now reused) ATCB. The critical thing here is to not make any 314 -- reference to the ATCB after the lock is released. See also comments on 315 -- Terminate_Task and Unlock. 316 317 procedure Final_Task_Unlock (Self_ID : Task_Id) is 318 begin 319 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting = 1); 320 Unlock (Global_Task_Lock'Access, Global_Lock => True); 321 end Final_Task_Unlock; 322 323 -------------- 324 -- Init_RTS -- 325 -------------- 326 327 procedure Init_RTS is 328 Self_Id : Task_Id; 329 begin 330 Tasking.Initialize; 331 332 -- Terminate run time (regular vs restricted) specific initialization 333 -- of the environment task. 334 335 Self_Id := Environment_Task; 336 Self_Id.Master_of_Task := Environment_Task_Level; 337 Self_Id.Master_Within := Self_Id.Master_of_Task + 1; 338 339 for L in Self_Id.Entry_Calls'Range loop 340 Self_Id.Entry_Calls (L).Self := Self_Id; 341 Self_Id.Entry_Calls (L).Level := L; 342 end loop; 343 344 Self_Id.Awake_Count := 1; 345 Self_Id.Alive_Count := 1; 346 347 -- Normally, a task starts out with internal master nesting level one 348 -- larger than external master nesting level. It is incremented to one 349 -- by Enter_Master, which is called in the task body only if the 350 -- compiler thinks the task may have dependent tasks. There is no 351 -- corresponding call to Enter_Master for the environment task, so we 352 -- would need to increment it to 2 here. Instead, we set it to 3. By 353 -- doing this we reserve the level 2 for server tasks of the runtime 354 -- system. The environment task does not need to wait for these server 355 356 Self_Id.Master_Within := Library_Task_Level; 357 358 -- Initialize lock used to implement mutual exclusion between all tasks 359 360 Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level); 361 362 -- Notify that the tasking run time has been elaborated so that 363 -- the tasking version of the soft links can be used. 364 365 if not No_Abort then 366 SSL.Abort_Defer := Abort_Defer'Access; 367 SSL.Abort_Undefer := Abort_Undefer'Access; 368 end if; 369 370 SSL.Lock_Task := Task_Lock'Access; 371 SSL.Unlock_Task := Task_Unlock'Access; 372 SSL.Check_Abort_Status := Check_Abort_Status'Access; 373 SSL.Task_Name := Task_Name'Access; 374 SSL.Update_Exception := Update_Exception'Access; 375 SSL.Get_Current_Excep := Get_Current_Excep'Access; 376 377 -- Initialize the tasking soft links (if not done yet) that are common 378 -- to the full and the restricted run times. 379 380 SSL.Tasking.Init_Tasking_Soft_Links; 381 382 -- Abort is deferred in a new ATCB, so we need to undefer abort at this 383 -- stage to make the environment task abortable. 384 385 Undefer_Abort (Environment_Task); 386 end Init_RTS; 387 388 --------------------------- 389 -- Locked_Abort_To_Level-- 390 --------------------------- 391 392 -- Abort a task to the specified ATC nesting level. 393 -- Call this only with T locked. 394 395 -- An earlier version of this code contained a call to Wakeup. That should 396 -- not be necessary here, if Abort_Task is implemented correctly, since 397 -- Abort_Task should include the effect of Wakeup. However, the above call 398 -- was in earlier versions of this file, and at least for some targets 399 -- Abort_Task has not been doing Wakeup. It should not hurt to uncomment 400 -- the above call, until the error is corrected for all targets. 401 402 -- See extended comments in package body System.Tasking.Abort for the 403 -- overall design of the implementation of task abort. 404 -- ??? there is no such package ??? 405 406 -- If the task is sleeping it will be in an abort-deferred region, and will 407 -- not have Abort_Signal raised by Abort_Task. Such an "abort deferral" is 408 -- just to protect the RTS internals, and not necessarily required to 409 -- enforce Ada semantics. Abort_Task should wake the task up and let it 410 -- decide if it wants to complete the aborted construct immediately. 411 412 -- Note that the effect of the low-level Abort_Task is not persistent. 413 -- If the target task is not blocked, this wakeup will be missed. 414 415 -- We don't bother calling Abort_Task if this task is aborting itself, 416 -- since we are inside the RTS and have abort deferred. Similarly, We don't 417 -- bother to call Abort_Task if T is terminated, since there is no need to 418 -- abort a terminated task, and it could be dangerous to try if the task 419 -- has stopped executing. 420 421 -- Note that an earlier version of this code had some false reasoning about 422 -- being able to reliably wake up a task that had suspended on a blocking 423 -- system call that does not atomically release the task's lock (e.g., UNIX 424 -- nanosleep, which we once thought could be used to implement delays). 425 -- That still left the possibility of missed wakeups. 426 427 -- We cannot safely call Vulnerable_Complete_Activation here, since that 428 -- requires locking Self_ID.Parent. The anti-deadlock lock ordering rules 429 -- would then require us to release the lock on Self_ID first, which would 430 -- create a timing window for other tasks to lock Self_ID. This is 431 -- significant for tasks that may be aborted before their execution can 432 -- enter the task body, and so they do not get a chance to call 433 -- Complete_Task. The actual work for this case is done in Terminate_Task. 434 435 procedure Locked_Abort_To_Level 436 (Self_ID : Task_Id; 437 T : Task_Id; 438 L : ATC_Level) 439 is 440 begin 441 if not T.Aborting and then T /= Self_ID then 442 case T.Common.State is 443 when Unactivated | Terminated => 444 pragma Assert (False); 445 null; 446 447 when Activating | Runnable => 448 449 -- This is needed to cancel an asynchronous protected entry 450 -- call during a requeue with abort. 451 452 T.Entry_Calls 453 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 454 455 when Interrupt_Server_Blocked_On_Event_Flag => 456 null; 457 458 when Delay_Sleep | 459 Async_Select_Sleep | 460 Interrupt_Server_Idle_Sleep | 461 Interrupt_Server_Blocked_Interrupt_Sleep | 462 Timer_Server_Sleep | 463 AST_Server_Sleep => 464 Wakeup (T, T.Common.State); 465 466 when Acceptor_Sleep | Acceptor_Delay_Sleep => 467 T.Open_Accepts := null; 468 Wakeup (T, T.Common.State); 469 470 when Entry_Caller_Sleep => 471 T.Entry_Calls 472 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 473 Wakeup (T, T.Common.State); 474 475 when Activator_Sleep | 476 Master_Completion_Sleep | 477 Master_Phase_2_Sleep | 478 Asynchronous_Hold => 479 null; 480 end case; 481 end if; 482 483 if T.Pending_ATC_Level > L then 484 T.Pending_ATC_Level := L; 485 T.Pending_Action := True; 486 487 if L = 0 then 488 T.Callable := False; 489 end if; 490 491 -- This prevents aborted task from accepting calls 492 493 if T.Aborting then 494 495 -- The test above is just a heuristic, to reduce wasteful 496 -- calls to Abort_Task. We are holding T locked, and this 497 -- value will not be set to False except with T also locked, 498 -- inside Exit_One_ATC_Level, so we should not miss wakeups. 499 500 if T.Common.State = Acceptor_Sleep 501 or else 502 T.Common.State = Acceptor_Delay_Sleep 503 then 504 T.Open_Accepts := null; 505 end if; 506 507 elsif T /= Self_ID and then 508 (T.Common.State = Runnable 509 or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag) 510 511 -- The task is blocked on a system call waiting for the 512 -- completion event. In this case Abort_Task may need to take 513 -- special action in order to succeed. 514 515 then 516 Abort_Task (T); 517 end if; 518 end if; 519 end Locked_Abort_To_Level; 520 521 -------------------------------- 522 -- Remove_From_All_Tasks_List -- 523 -------------------------------- 524 525 procedure Remove_From_All_Tasks_List (T : Task_Id) is 526 C : Task_Id; 527 Previous : Task_Id; 528 529 begin 530 pragma Debug 531 (Debug.Trace (Self, "Remove_From_All_Tasks_List", 'C')); 532 533 Previous := Null_Task; 534 C := All_Tasks_List; 535 while C /= Null_Task loop 536 if C = T then 537 if Previous = Null_Task then 538 All_Tasks_List := All_Tasks_List.Common.All_Tasks_Link; 539 else 540 Previous.Common.All_Tasks_Link := C.Common.All_Tasks_Link; 541 end if; 542 543 return; 544 end if; 545 546 Previous := C; 547 C := C.Common.All_Tasks_Link; 548 end loop; 549 550 pragma Assert (False); 551 end Remove_From_All_Tasks_List; 552 553 --------------- 554 -- Task_Lock -- 555 --------------- 556 557 procedure Task_Lock (Self_ID : Task_Id) is 558 begin 559 Self_ID.Common.Global_Task_Lock_Nesting := 560 Self_ID.Common.Global_Task_Lock_Nesting + 1; 561 562 if Self_ID.Common.Global_Task_Lock_Nesting = 1 then 563 Defer_Abort_Nestable (Self_ID); 564 Write_Lock (Global_Task_Lock'Access, Global_Lock => True); 565 end if; 566 end Task_Lock; 567 568 procedure Task_Lock is 569 begin 570 Task_Lock (STPO.Self); 571 end Task_Lock; 572 573 --------------- 574 -- Task_Name -- 575 --------------- 576 577 function Task_Name return String is 578 Self_Id : constant Task_Id := STPO.Self; 579 begin 580 return Self_Id.Common.Task_Image (1 .. Self_Id.Common.Task_Image_Len); 581 end Task_Name; 582 583 ----------------- 584 -- Task_Unlock -- 585 ----------------- 586 587 procedure Task_Unlock (Self_ID : Task_Id) is 588 begin 589 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting > 0); 590 Self_ID.Common.Global_Task_Lock_Nesting := 591 Self_ID.Common.Global_Task_Lock_Nesting - 1; 592 593 if Self_ID.Common.Global_Task_Lock_Nesting = 0 then 594 Unlock (Global_Task_Lock'Access, Global_Lock => True); 595 Undefer_Abort_Nestable (Self_ID); 596 end if; 597 end Task_Unlock; 598 599 procedure Task_Unlock is 600 begin 601 Task_Unlock (STPO.Self); 602 end Task_Unlock; 603 604 ------------------- 605 -- Undefer_Abort -- 606 ------------------- 607 608 -- Precondition : Self does not hold any locks 609 610 -- Undefer_Abort is called on any abort completion point (aka. 611 -- synchronization point). It performs the following actions if they 612 -- are pending: (1) change the base priority, (2) abort the task. 613 614 -- The priority change has to occur before abort. Otherwise, it would 615 -- take effect no earlier than the next abort completion point. 616 617 procedure Undefer_Abort (Self_ID : Task_Id) is 618 begin 619 if No_Abort then 620 return; 621 end if; 622 623 pragma Assert (Self_ID.Deferral_Level = 1); 624 625 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 626 627 if Self_ID.Deferral_Level = 0 then 628 pragma Assert (Check_No_Locks (Self_ID)); 629 630 if Self_ID.Pending_Action then 631 Do_Pending_Action (Self_ID); 632 end if; 633 end if; 634 end Undefer_Abort; 635 636 ---------------------------- 637 -- Undefer_Abort_Nestable -- 638 ---------------------------- 639 640 -- An earlier version would re-defer abort if an abort is in progress. 641 -- Then, we modified the effect of the raise statement so that it defers 642 -- abort until control reaches a handler. That was done to prevent 643 -- "skipping over" a handler if another asynchronous abort occurs during 644 -- the propagation of the abort to the handler. 645 646 -- There has been talk of reversing that decision, based on a newer 647 -- implementation of exception propagation. Care must be taken to evaluate 648 -- how such a change would interact with the above code and all the places 649 -- where abort-deferral is used to bridge over critical transitions, such 650 -- as entry to the scope of a region with a finalizer and entry into the 651 -- body of an accept-procedure. 652 653 procedure Undefer_Abort_Nestable (Self_ID : Task_Id) is 654 begin 655 if No_Abort then 656 return; 657 end if; 658 659 pragma Assert (Self_ID.Deferral_Level > 0); 660 661 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 662 663 if Self_ID.Deferral_Level = 0 then 664 665 pragma Assert (Check_No_Locks (Self_ID)); 666 667 if Self_ID.Pending_Action then 668 Do_Pending_Action (Self_ID); 669 end if; 670 end if; 671 end Undefer_Abort_Nestable; 672 673 ------------------- 674 -- Abort_Undefer -- 675 ------------------- 676 677 procedure Abort_Undefer is 678 Self_ID : Task_Id; 679 begin 680 if No_Abort then 681 return; 682 end if; 683 684 Self_ID := STPO.Self; 685 686 if Self_ID.Deferral_Level = 0 then 687 688 -- In case there are different views on whether Abort is supported 689 -- between the expander and the run time, we may end up with 690 -- Self_ID.Deferral_Level being equal to zero, when called from 691 -- the procedure created by the expander that corresponds to a 692 -- task body. In this case, there's nothing to be done. 693 694 -- See related code in System.Tasking.Stages.Create_Task resetting 695 -- Deferral_Level when System.Restrictions.Abort_Allowed is False. 696 697 return; 698 end if; 699 700 pragma Assert (Self_ID.Deferral_Level > 0); 701 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 702 703 if Self_ID.Deferral_Level = 0 then 704 pragma Assert (Check_No_Locks (Self_ID)); 705 706 if Self_ID.Pending_Action then 707 Do_Pending_Action (Self_ID); 708 end if; 709 end if; 710 end Abort_Undefer; 711 712 ---------------------- 713 -- Update_Exception -- 714 ---------------------- 715 716 -- Call only when holding no locks 717 718 procedure Update_Exception 719 (X : AE.Exception_Occurrence := SSL.Current_Target_Exception) 720 is 721 Self_Id : constant Task_Id := Self; 722 use Ada.Exceptions; 723 724 begin 725 Save_Occurrence (Self_Id.Common.Compiler_Data.Current_Excep, X); 726 727 if Self_Id.Deferral_Level = 0 then 728 if Self_Id.Pending_Action then 729 Self_Id.Pending_Action := False; 730 Self_Id.Deferral_Level := Self_Id.Deferral_Level + 1; 731 732 if Single_Lock then 733 Lock_RTS; 734 end if; 735 736 Write_Lock (Self_Id); 737 Self_Id.Pending_Action := False; 738 Unlock (Self_Id); 739 740 if Single_Lock then 741 Unlock_RTS; 742 end if; 743 744 Self_Id.Deferral_Level := Self_Id.Deferral_Level - 1; 745 746 if Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level then 747 if not Self_Id.Aborting then 748 Self_Id.Aborting := True; 749 raise Standard'Abort_Signal; 750 end if; 751 end if; 752 end if; 753 end if; 754 end Update_Exception; 755 756 -------------------------- 757 -- Wakeup_Entry_Caller -- 758 -------------------------- 759 760 -- This is called at the end of service of an entry call, to abort the 761 -- caller if he is in an abortable part, and to wake up the caller if it 762 -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue. 763 764 -- (This enforces the rule that a task must be off-queue if its state is 765 -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self. 766 767 -- Timed_Call or Simple_Call: 768 -- The caller is waiting on Entry_Caller_Sleep, in 769 -- Wait_For_Completion, or Wait_For_Completion_With_Timeout. 770 771 -- Conditional_Call: 772 -- The caller might be in Wait_For_Completion, 773 -- waiting for a rendezvous (possibly requeued without abort) 774 -- to complete. 775 776 -- Asynchronous_Call: 777 -- The caller may be executing in the abortable part o 778 -- an async. select, or on a time delay, 779 -- if Entry_Call.State >= Was_Abortable. 780 781 procedure Wakeup_Entry_Caller 782 (Self_ID : Task_Id; 783 Entry_Call : Entry_Call_Link; 784 New_State : Entry_Call_State) 785 is 786 Caller : constant Task_Id := Entry_Call.Self; 787 788 begin 789 pragma Debug (Debug.Trace 790 (Self_ID, "Wakeup_Entry_Caller", 'E', Caller)); 791 pragma Assert (New_State = Done or else New_State = Cancelled); 792 793 pragma Assert (Caller.Common.State /= Unactivated); 794 795 Entry_Call.State := New_State; 796 797 if Entry_Call.Mode = Asynchronous_Call then 798 799 -- Abort the caller in his abortable part, but do so only if call has 800 -- been queued abortably. 801 802 if Entry_Call.State >= Was_Abortable or else New_State = Done then 803 Locked_Abort_To_Level (Self_ID, Caller, Entry_Call.Level - 1); 804 end if; 805 806 elsif Caller.Common.State = Entry_Caller_Sleep then 807 Wakeup (Caller, Entry_Caller_Sleep); 808 end if; 809 end Wakeup_Entry_Caller; 810 811 ------------------------- 812 -- Finalize_Attributes -- 813 ------------------------- 814 815 procedure Finalize_Attributes (T : Task_Id) is 816 Attr : Atomic_Address; 817 818 begin 819 for J in T.Attributes'Range loop 820 Attr := T.Attributes (J); 821 822 if Attr /= 0 and then Task_Attributes.Require_Finalization (J) then 823 Task_Attributes.To_Attribute (Attr).Free (Attr); 824 T.Attributes (J) := 0; 825 end if; 826 end loop; 827 end Finalize_Attributes; 828 829begin 830 Init_RTS; 831end System.Tasking.Initialization; 832