gcc/ada/5ztaprop.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS              --
   4 --                                                                          --
   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    --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --                             $Revision: 1.2 $
  10 --                                                                          --
  11 --             Copyright (C) 1991-2001 Florida State University             --
  12 --                                                                          --
  13 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNARL was developed by the GNARL team at Florida State University. It is --
  32 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  33 -- State University (http://www.gnat.com).                                  --
  34 --                                                                          --
  35 ------------------------------------------------------------------------------
  36
  37 --  This is the VxWorks version of this package
  38
  39 --  This package contains all the GNULL primitives that interface directly
  40 --  with the underlying OS.
  41
  42 pragma Polling (Off);
  43 --  Turn off polling, we do not want ATC polling to take place during
  44 --  tasking operations. It causes infinite loops and other problems.
  45
  46 with System.Tasking.Debug;
  47 --  used for Known_Tasks
  48
  49 with Interfaces.C;
  50 --  used for int
  51 --           size_t
  52
  53 with System.Interrupt_Management;
  54 --  used for Keep_Unmasked
  55 --           Abort_Task_Interrupt
  56 --           Interrupt_ID
  57 --           Initialize_Interrupts
  58
  59 with System.Soft_Links;
  60 --  used for Defer/Undefer_Abort
  61
  62 --  Note that we do not use System.Tasking.Initialization directly since
  63 --  this is a higher level package that we shouldn't depend on. For example
  64 --  when using the restricted run time, it is replaced by
  65 --  System.Tasking.Restricted.Initialization
  66
  67 with System.OS_Interface;
  68 --  used for various type, constant, and operations
  69
  70 with System.Parameters;
  71 --  used for Size_Type
  72
  73 with System.Tasking;
  74 --  used for Ada_Task_Control_Block
  75 --           Task_ID
  76 --           ATCB components and types
  77
  78 with System.Task_Info;
  79 --  used for Task_Image
  80
  81 with System.OS_Primitives;
  82 --  used for Delay_Modes
  83
  84 with System.VxWorks;
  85 --  used for TASK_DESC
  86
  87 with Unchecked_Conversion;
  88 with Unchecked_Deallocation;
  89
  90 package body System.Task_Primitives.Operations is
  91
  92    use System.Tasking.Debug;
  93    use System.Tasking;
  94    use System.Task_Info;
  95    use Interfaces.C;
  96    use System.OS_Interface;
  97    use System.Parameters;
  98    use System.OS_Primitives;
  99
 100    package SSL renames System.Soft_Links;
 101
 102    ------------------
 103    --  Local Data  --
 104    ------------------
 105
 106    --  The followings are logically constants, but need to be initialized
 107    --  at run time.
 108
 109    ATCB_Key : aliased pthread_key_t;
 110    --  Key used to find the Ada Task_ID associated with a VxWorks task.
 111
 112    All_Tasks_L : aliased System.Task_Primitives.RTS_Lock;
 113    --  See comments on locking rules in System.Tasking (spec).
 114
 115    Environment_Task_ID : Task_ID;
 116    --  A variable to hold Task_ID for the environment task.
 117
 118    Unblocked_Signal_Mask : aliased sigset_t;
 119    --  The set of signals that should unblocked in all tasks
 120
 121    --  The followings are internal configuration constants needed.
 122
 123    Time_Slice_Val : Integer;
 124    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 125
 126    Locking_Policy : Character;
 127    pragma Import (C, Locking_Policy, "__gl_locking_policy");
 128
 129    Dispatching_Policy : Character;
 130    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 131
 132    FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
 133    --  Indicates whether FIFO_Within_Priorities is set.
 134
 135    Mutex_Protocol : Interfaces.C.int;
 136
 137    Stack_Limit : aliased System.Address;
 138    pragma Import (C, Stack_Limit, "__gnat_stack_limit");
 139
 140    -----------------------
 141    -- Local Subprograms --
 142    -----------------------
 143
 144    procedure Abort_Handler (signo : Signal);
 145
 146    function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
 147
 148    function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
 149
 150    -------------------
 151    -- Abort_Handler --
 152    -------------------
 153
 154    procedure Abort_Handler (signo : Signal) is
 155       Self_ID : constant Task_ID := Self;
 156       Result  : Interfaces.C.int;
 157       Old_Set : aliased sigset_t;
 158
 159    begin
 160       if Self_ID.Deferral_Level = 0
 161         and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level and then
 162         not Self_ID.Aborting
 163       then
 164          Self_ID.Aborting := True;
 165
 166          --  Make sure signals used for RTS internal purpose are unmasked
 167
 168          Result := pthread_sigmask (SIG_UNBLOCK,
 169            Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
 170          pragma Assert (Result = 0);
 171
 172          raise Standard'Abort_Signal;
 173       end if;
 174    end Abort_Handler;
 175
 176    -----------------
 177    -- Stack_Guard --
 178    -----------------
 179
 180    procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
 181       Task_Descriptor : aliased System.VxWorks.TASK_DESC;
 182       Result          : Interfaces.C.int;
 183
 184    begin
 185       if On then
 186          Result := taskInfoGet (T.Common.LL.Thread,
 187            Task_Descriptor'Unchecked_Access);
 188          pragma Assert (Result = 0);
 189
 190          Stack_Limit := Task_Descriptor.td_pStackLimit;
 191       end if;
 192    end Stack_Guard;
 193
 194    -------------------
 195    -- Get_Thread_Id --
 196    -------------------
 197
 198    function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
 199    begin
 200       return T.Common.LL.Thread;
 201    end Get_Thread_Id;
 202
 203    ----------
 204    -- Self --
 205    ----------
 206
 207    function Self return Task_ID is
 208       Result : System.Address;
 209
 210    begin
 211       Result := pthread_getspecific (ATCB_Key);
 212       pragma Assert (Result /= System.Null_Address);
 213       return To_Task_ID (Result);
 214    end Self;
 215
 216    -----------------------------
 217    -- Install_Signal_Handlers --
 218    -----------------------------
 219
 220    procedure Install_Signal_Handlers;
 221    pragma Inline (Install_Signal_Handlers);
 222
 223    procedure Install_Signal_Handlers is
 224       act       : aliased struct_sigaction;
 225       old_act   : aliased struct_sigaction;
 226       Tmp_Set   : aliased sigset_t;
 227       Result    : Interfaces.C.int;
 228
 229    begin
 230       act.sa_flags := 0;
 231       act.sa_handler := Abort_Handler'Address;
 232
 233       Result := sigemptyset (Tmp_Set'Access);
 234       pragma Assert (Result = 0);
 235       act.sa_mask := Tmp_Set;
 236
 237       Result :=
 238         sigaction
 239           (Signal (Interrupt_Management.Abort_Task_Interrupt),
 240            act'Unchecked_Access,
 241            old_act'Unchecked_Access);
 242       pragma Assert (Result = 0);
 243
 244       Interrupt_Management.Initialize_Interrupts;
 245    end Install_Signal_Handlers;
 246
 247    ---------------------
 248    -- Initialize_Lock --
 249    ---------------------
 250
 251    --  Note: mutexes and cond_variables needed per-task basis are
 252    --        initialized in Initialize_TCB and the Storage_Error is
 253    --        handled. Other mutexes (such as All_Tasks_Lock, Memory_Lock...)
 254    --        used in RTS is initialized before any status change of RTS.
 255    --        Therefore rasing Storage_Error in the following routines
 256    --        should be able to be handled safely.
 257
 258    procedure Initialize_Lock
 259      (Prio : System.Any_Priority;
 260       L    : access Lock)
 261    is
 262       Attributes : aliased pthread_mutexattr_t;
 263       Result : Interfaces.C.int;
 264    begin
 265       Result := pthread_mutexattr_init (Attributes'Access);
 266       pragma Assert (Result = 0 or else Result = ENOMEM);
 267
 268       if Result = ENOMEM then
 269          raise Storage_Error;
 270       end if;
 271
 272       Result := pthread_mutexattr_setprotocol
 273         (Attributes'Access, Mutex_Protocol);
 274       pragma Assert (Result = 0);
 275
 276       Result := pthread_mutexattr_setprioceiling
 277          (Attributes'Access, Interfaces.C.int (Prio));
 278       pragma Assert (Result = 0);
 279
 280       Result := pthread_mutex_init (L, Attributes'Access);
 281       pragma Assert (Result = 0 or else Result = ENOMEM);
 282
 283       if Result = ENOMEM then
 284          raise Storage_Error;
 285       end if;
 286
 287       Result := pthread_mutexattr_destroy (Attributes'Access);
 288       pragma Assert (Result = 0);
 289    end Initialize_Lock;
 290
 291    procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
 292       Attributes : aliased pthread_mutexattr_t;
 293       Result : Interfaces.C.int;
 294
 295    begin
 296       Result := pthread_mutexattr_init (Attributes'Access);
 297       pragma Assert (Result = 0 or else Result = ENOMEM);
 298
 299       if Result = ENOMEM then
 300          raise Storage_Error;
 301       end if;
 302
 303       Result := pthread_mutexattr_setprotocol
 304         (Attributes'Access, Mutex_Protocol);
 305       pragma Assert (Result = 0);
 306
 307       Result := pthread_mutexattr_setprioceiling
 308         (Attributes'Access,
 309          Interfaces.C.int (System.Any_Priority'Last));
 310       pragma Assert (Result = 0);
 311
 312       Result := pthread_mutex_init (L, Attributes'Access);
 313       pragma Assert (Result = 0 or else Result = ENOMEM);
 314
 315       if Result = ENOMEM then
 316          raise Storage_Error;
 317       end if;
 318
 319       Result := pthread_mutexattr_destroy (Attributes'Access);
 320       pragma Assert (Result = 0);
 321    end Initialize_Lock;
 322
 323    -------------------
 324    -- Finalize_Lock --
 325    -------------------
 326
 327    procedure Finalize_Lock (L : access Lock) is
 328       Result : Interfaces.C.int;
 329
 330    begin
 331       Result := pthread_mutex_destroy (L);
 332       pragma Assert (Result = 0);
 333    end Finalize_Lock;
 334
 335    procedure Finalize_Lock (L : access RTS_Lock) is
 336       Result : Interfaces.C.int;
 337
 338    begin
 339       Result := pthread_mutex_destroy (L);
 340       pragma Assert (Result = 0);
 341    end Finalize_Lock;
 342
 343    ----------------
 344    -- Write_Lock --
 345    ----------------
 346
 347    procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 348       Result     : Interfaces.C.int;
 349
 350    begin
 351       Result := pthread_mutex_lock (L);
 352
 353       --  Assume that the cause of EINVAL is a priority ceiling violation
 354
 355       Ceiling_Violation := (Result = EINVAL);
 356       pragma Assert (Result = 0 or else Result = EINVAL);
 357    end Write_Lock;
 358
 359    procedure Write_Lock (L : access RTS_Lock) is
 360       Result : Interfaces.C.int;
 361
 362    begin
 363       Result := pthread_mutex_lock (L);
 364       pragma Assert (Result = 0);
 365    end Write_Lock;
 366
 367    procedure Write_Lock (T : Task_ID) is
 368       Result : Interfaces.C.int;
 369
 370    begin
 371       Result := pthread_mutex_lock (T.Common.LL.L'Access);
 372       pragma Assert (Result = 0);
 373    end Write_Lock;
 374
 375    ---------------
 376    -- Read_Lock --
 377    ---------------
 378
 379    procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 380    begin
 381       Write_Lock (L, Ceiling_Violation);
 382    end Read_Lock;
 383
 384    ------------
 385    -- Unlock --
 386    ------------
 387
 388    procedure Unlock (L : access Lock) is
 389       Result  : Interfaces.C.int;
 390
 391    begin
 392       Result := pthread_mutex_unlock (L);
 393       pragma Assert (Result = 0);
 394    end Unlock;
 395
 396    procedure Unlock (L : access RTS_Lock) is
 397       Result : Interfaces.C.int;
 398
 399    begin
 400       Result := pthread_mutex_unlock (L);
 401       pragma Assert (Result = 0);
 402    end Unlock;
 403
 404    procedure Unlock (T : Task_ID) is
 405       Result : Interfaces.C.int;
 406
 407    begin
 408       Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 409       pragma Assert (Result = 0);
 410    end Unlock;
 411
 412    -------------
 413    --  Sleep  --
 414    -------------
 415
 416    procedure Sleep (Self_ID : Task_ID;
 417                     Reason   : System.Tasking.Task_States) is
 418       Result : Interfaces.C.int;
 419
 420    begin
 421       pragma Assert (Self_ID = Self);
 422       Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access,
 423         Self_ID.Common.LL.L'Access);
 424
 425       --  EINTR is not considered a failure.
 426
 427       pragma Assert (Result = 0 or else Result = EINTR);
 428    end Sleep;
 429
 430    -----------------
 431    -- Timed_Sleep --
 432    -----------------
 433
 434    --  This is for use within the run-time system, so abort is
 435    --  assumed to be already deferred, and the caller should be
 436    --  holding its own ATCB lock.
 437
 438    procedure Timed_Sleep
 439      (Self_ID  : Task_ID;
 440       Time     : Duration;
 441       Mode     : ST.Delay_Modes;
 442       Reason   : System.Tasking.Task_States;
 443       Timedout : out Boolean;
 444       Yielded  : out Boolean)
 445    is
 446       Check_Time : constant Duration := Monotonic_Clock;
 447       Abs_Time   : Duration;
 448       Request    : aliased timespec;
 449       Result     : Interfaces.C.int;
 450
 451    begin
 452       Timedout := True;
 453       Yielded := False;
 454
 455       if Mode = Relative then
 456          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 457       else
 458          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 459       end if;
 460
 461       if Abs_Time > Check_Time then
 462          Request := To_Timespec (Abs_Time);
 463          loop
 464             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 465               or else Self_ID.Pending_Priority_Change;
 466
 467             Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 468               Self_ID.Common.LL.L'Access, Request'Access);
 469             Yielded := True;
 470             exit when Abs_Time <= Monotonic_Clock;
 471
 472             if Result = 0 or Result = EINTR then
 473
 474                --  Somebody may have called Wakeup for us
 475
 476                Timedout := False;
 477                exit;
 478             end if;
 479
 480             pragma Assert (Result = ETIMEDOUT);
 481          end loop;
 482       end if;
 483    end Timed_Sleep;
 484
 485    -----------------
 486    -- Timed_Delay --
 487    -----------------
 488
 489    --  This is for use in implementing delay statements, so
 490    --  we assume the caller is abort-deferred but is holding
 491    --  no locks.
 492
 493    procedure Timed_Delay
 494      (Self_ID  : Task_ID;
 495       Time     : Duration;
 496       Mode     : ST.Delay_Modes)
 497    is
 498       Check_Time : constant Duration := Monotonic_Clock;
 499       Abs_Time   : Duration;
 500       Request    : aliased timespec;
 501       Result     : Interfaces.C.int;
 502       Yielded    : Boolean := False;
 503    begin
 504
 505       --  Only the little window between deferring abort and
 506       --  locking Self_ID is the reason we need to
 507       --  check for pending abort and priority change below! :(
 508
 509       SSL.Abort_Defer.all;
 510       Write_Lock (Self_ID);
 511
 512       if Mode = Relative then
 513          Abs_Time := Time + Check_Time;
 514       else
 515          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 516       end if;
 517
 518       if Abs_Time > Check_Time then
 519          Request := To_Timespec (Abs_Time);
 520          Self_ID.Common.State := Delay_Sleep;
 521
 522          loop
 523             if Self_ID.Pending_Priority_Change then
 524                Self_ID.Pending_Priority_Change := False;
 525                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 526                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 527             end if;
 528
 529             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 530
 531             Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 532               Self_ID.Common.LL.L'Access, Request'Access);
 533             Yielded := True;
 534             exit when Abs_Time <= Monotonic_Clock;
 535
 536             pragma Assert (Result = 0
 537                              or else Result = ETIMEDOUT
 538                              or else Result = EINTR);
 539          end loop;
 540
 541          Self_ID.Common.State := Runnable;
 542       end if;
 543
 544       Unlock (Self_ID);
 545
 546       if not Yielded then
 547          Result := sched_yield;
 548       end if;
 549       SSL.Abort_Undefer.all;
 550    end Timed_Delay;
 551
 552    ---------------------
 553    -- Monotonic_Clock --
 554    ---------------------
 555
 556    function Monotonic_Clock return Duration is
 557       TS     : aliased timespec;
 558       Result : Interfaces.C.int;
 559    begin
 560       Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 561       pragma Assert (Result = 0);
 562       return To_Duration (TS);
 563    end Monotonic_Clock;
 564
 565    -------------------
 566    -- RT_Resolution --
 567    -------------------
 568
 569    function RT_Resolution return Duration is
 570    begin
 571       return 10#1.0#E-6;
 572    end RT_Resolution;
 573
 574    ------------
 575    -- Wakeup --
 576    ------------
 577
 578    procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is
 579       Result : Interfaces.C.int;
 580
 581    begin
 582       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 583       pragma Assert (Result = 0);
 584    end Wakeup;
 585
 586    -----------
 587    -- Yield --
 588    -----------
 589
 590    procedure Yield (Do_Yield : Boolean := True) is
 591       Result : Interfaces.C.int;
 592
 593    begin
 594       Result := sched_yield;
 595    end Yield;
 596
 597    ------------------
 598    -- Set_Priority --
 599    ------------------
 600
 601    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 602    pragma Atomic_Components (Prio_Array_Type);
 603
 604    Prio_Array : Prio_Array_Type;
 605    --  Global array containing the id of the currently running task for
 606    --  each priority.
 607    --
 608    --  Note: we assume that we are on a single processor with run-til-blocked
 609    --  scheduling.
 610
 611    procedure Set_Priority
 612      (T : Task_ID;
 613       Prio : System.Any_Priority;
 614       Loss_Of_Inheritance : Boolean := False)
 615    is
 616       Param      : aliased struct_sched_param;
 617       Array_Item : Integer;
 618       Result     : Interfaces.C.int;
 619
 620    begin
 621       Param.sched_priority := Interfaces.C.int (Prio);
 622
 623       if Time_Slice_Val <= 0 then
 624          Result := pthread_setschedparam
 625            (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 626       else
 627          Result := pthread_setschedparam
 628            (T.Common.LL.Thread, SCHED_RR, Param'Access);
 629       end if;
 630
 631       pragma Assert (Result = 0);
 632
 633       if FIFO_Within_Priorities then
 634
 635          --  Annex D requirement [RM D.2.2 par. 9]:
 636          --    If the task drops its priority due to the loss of inherited
 637          --    priority, it is added at the head of the ready queue for its
 638          --    new active priority.
 639
 640          if Loss_Of_Inheritance
 641            and then Prio < T.Common.Current_Priority
 642          then
 643             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 644             Prio_Array (T.Common.Base_Priority) := Array_Item;
 645
 646             loop
 647                --  Let some processes a chance to arrive
 648
 649                Yield;
 650
 651                --  Then wait for our turn to proceed
 652
 653                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 654                  or else Prio_Array (T.Common.Base_Priority) = 1;
 655             end loop;
 656
 657             Prio_Array (T.Common.Base_Priority) :=
 658               Prio_Array (T.Common.Base_Priority) - 1;
 659          end if;
 660       end if;
 661
 662       T.Common.Current_Priority := Prio;
 663    end Set_Priority;
 664
 665    ------------------
 666    -- Get_Priority --
 667    ------------------
 668
 669    function Get_Priority (T : Task_ID) return System.Any_Priority is
 670    begin
 671       return T.Common.Current_Priority;
 672    end Get_Priority;
 673
 674    ----------------
 675    -- Enter_Task --
 676    ----------------
 677
 678    procedure Enter_Task (Self_ID : Task_ID) is
 679       Result  : Interfaces.C.int;
 680
 681       procedure Init_Float;
 682       pragma Import (C, Init_Float, "__gnat_init_float");
 683       --  Properly initializes the FPU for PPC/MIPS systems.
 684
 685    begin
 686       Self_ID.Common.LL.Thread := pthread_self;
 687
 688       Result := pthread_setspecific (ATCB_Key, To_Address (Self_ID));
 689       pragma Assert (Result = 0);
 690
 691       Init_Float;
 692
 693       --  Install the signal handlers.
 694       --  This is called for each task since there is no signal inheritance
 695       --  between VxWorks tasks.
 696
 697       Install_Signal_Handlers;
 698
 699       Lock_All_Tasks_List;
 700
 701       for T in Known_Tasks'Range loop
 702          if Known_Tasks (T) = null then
 703             Known_Tasks (T) := Self_ID;
 704             Self_ID.Known_Tasks_Index := T;
 705             exit;
 706          end if;
 707       end loop;
 708
 709       Unlock_All_Tasks_List;
 710    end Enter_Task;
 711
 712    --------------
 713    -- New_ATCB --
 714    --------------
 715
 716    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
 717    begin
 718       return new Ada_Task_Control_Block (Entry_Num);
 719    end New_ATCB;
 720
 721    ----------------------
 722    --  Initialize_TCB  --
 723    ----------------------
 724
 725    procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
 726       Mutex_Attr : aliased pthread_mutexattr_t;
 727       Result : Interfaces.C.int;
 728       Cond_Attr : aliased pthread_condattr_t;
 729
 730    begin
 731       Self_ID.Common.LL.Thread := null_pthread;
 732
 733       Result := pthread_mutexattr_init (Mutex_Attr'Access);
 734       pragma Assert (Result = 0 or else Result = ENOMEM);
 735
 736       if Result /= 0 then
 737          Succeeded := False;
 738          return;
 739       end if;
 740
 741       Result := pthread_mutexattr_setprotocol
 742         (Mutex_Attr'Access, Mutex_Protocol);
 743       pragma Assert (Result = 0);
 744
 745       Result := pthread_mutexattr_setprioceiling
 746         (Mutex_Attr'Access, Interfaces.C.int (System.Any_Priority'Last));
 747       pragma Assert (Result = 0);
 748
 749       Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 750         Mutex_Attr'Access);
 751       pragma Assert (Result = 0 or else Result = ENOMEM);
 752
 753       if Result /= 0 then
 754          Succeeded := False;
 755          return;
 756       end if;
 757
 758       Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 759       pragma Assert (Result = 0);
 760
 761       Result := pthread_condattr_init (Cond_Attr'Access);
 762       pragma Assert (Result = 0 or else Result = ENOMEM);
 763
 764       if Result /= 0 then
 765          Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 766          pragma Assert (Result = 0);
 767          Succeeded := False;
 768          return;
 769       end if;
 770
 771       Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 772         Cond_Attr'Access);
 773       pragma Assert (Result = 0 or else Result = ENOMEM);
 774
 775       if Result = 0 then
 776          Succeeded := True;
 777       else
 778          Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 779          pragma Assert (Result = 0);
 780          Succeeded := False;
 781       end if;
 782
 783       Result := pthread_condattr_destroy (Cond_Attr'Access);
 784       pragma Assert (Result = 0);
 785    end Initialize_TCB;
 786
 787    -----------------
 788    -- Create_Task --
 789    -----------------
 790
 791    procedure Create_Task
 792      (T          : Task_ID;
 793       Wrapper    : System.Address;
 794       Stack_Size : System.Parameters.Size_Type;
 795       Priority   : System.Any_Priority;
 796       Succeeded  : out Boolean)
 797    is
 798       use type System.Task_Info.Task_Image_Type;
 799
 800       Adjusted_Stack_Size : Interfaces.C.size_t;
 801       Attributes          : aliased pthread_attr_t;
 802       Result              : Interfaces.C.int;
 803
 804       function Thread_Body_Access is new
 805         Unchecked_Conversion (System.Address, Thread_Body);
 806
 807    begin
 808       if Stack_Size = Unspecified_Size then
 809          Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
 810
 811       elsif Stack_Size < Minimum_Stack_Size then
 812          Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
 813
 814       else
 815          Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
 816       end if;
 817
 818       --  Ask for 4 extra bytes of stack space so that the ATCB
 819       --  pointer can be stored below the stack limit, plus extra
 820       --  space for the frame of Task_Wrapper.  This is so the user
 821       --  gets the amount of stack requested exclusive of the needs
 822       --  of the runtime.
 823       --
 824       --  We also have to allocate 10 more bytes for the task name
 825       --  storage and enough space for the Wind Task Control Block
 826       --  which is around 0x778 bytes.  VxWorks also seems to carve out
 827       --  additional space, so use 2048 as a nice round number.
 828       --  We might want to increment to the nearest page size in
 829       --  case we ever support VxVMI.
 830       --
 831       --  XXX - we should come back and visit this so we can
 832       --        set the task name to something appropriate.
 833       Adjusted_Stack_Size := Adjusted_Stack_Size + 2048;
 834
 835       Result := pthread_attr_init (Attributes'Access);
 836       pragma Assert (Result = 0 or else Result = ENOMEM);
 837
 838       if Result /= 0 then
 839          Succeeded := False;
 840          return;
 841       end if;
 842
 843       Result := pthread_attr_setdetachstate
 844         (Attributes'Access, PTHREAD_CREATE_DETACHED);
 845       pragma Assert (Result = 0);
 846
 847       Result := pthread_attr_setstacksize
 848         (Attributes'Access, Adjusted_Stack_Size);
 849       pragma Assert (Result = 0);
 850
 851       --  Let's check to see if the task has an image string and
 852       --  use that as the VxWorks task name.
 853       if T.Common.Task_Image /= null then
 854          declare
 855             Task_Name : aliased constant String :=
 856               T.Common.Task_Image.all & ASCII.NUL;
 857          begin
 858             Result := pthread_attr_setname_np
 859               (Attributes'Access, Task_Name'Address);
 860
 861             --  Since the initial signal mask of a thread is inherited from the
 862             --  creator, and the Environment task has all its signals masked,
 863             --  we do not need to manipulate caller's signal mask at this
 864             --  point. All tasks in RTS will have All_Tasks_Mask initially.
 865             Result := pthread_create
 866               (T.Common.LL.Thread'Access,
 867                Attributes'Access,
 868                Thread_Body_Access (Wrapper),
 869                To_Address (T));
 870          end;
 871       else
 872          --  No specified task name
 873          Result := pthread_create
 874            (T.Common.LL.Thread'Access,
 875             Attributes'Access,
 876             Thread_Body_Access (Wrapper),
 877             To_Address (T));
 878       end if;
 879       pragma Assert (Result = 0);
 880
 881       Succeeded := Result = 0;
 882
 883       Result := pthread_attr_destroy (Attributes'Access);
 884       pragma Assert (Result = 0);
 885
 886       Task_Creation_Hook (T.Common.LL.Thread);
 887
 888       Set_Priority (T, Priority);
 889    end Create_Task;
 890
 891    ------------------
 892    -- Finalize_TCB --
 893    ------------------
 894
 895    procedure Finalize_TCB (T : Task_ID) is
 896       Result : Interfaces.C.int;
 897       Tmp    : Task_ID := T;
 898
 899       procedure Free is new
 900         Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
 901
 902    begin
 903       T.Common.LL.Thread := null_pthread;
 904
 905       Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 906       pragma Assert (Result = 0);
 907
 908       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 909       pragma Assert (Result = 0);
 910
 911       if T.Known_Tasks_Index /= -1 then
 912          Known_Tasks (T.Known_Tasks_Index) := null;
 913       end if;
 914
 915       Free (Tmp);
 916    end Finalize_TCB;
 917
 918    ---------------
 919    -- Exit_Task --
 920    ---------------
 921
 922    procedure Exit_Task is
 923    begin
 924       Task_Termination_Hook;
 925       pthread_exit (System.Null_Address);
 926    end Exit_Task;
 927
 928    ----------------
 929    -- Abort_Task --
 930    ----------------
 931
 932    procedure Abort_Task (T : Task_ID) is
 933       Result : Interfaces.C.int;
 934    begin
 935       Result := kill (T.Common.LL.Thread,
 936         Signal (Interrupt_Management.Abort_Task_Interrupt));
 937       pragma Assert (Result = 0);
 938    end Abort_Task;
 939
 940    ----------------
 941    -- Check_Exit --
 942    ----------------
 943
 944    --  Dummy versions. The only currently working versions is for solaris
 945    --  (native).
 946
 947    function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
 948    begin
 949       return True;
 950    end Check_Exit;
 951
 952    --------------------
 953    -- Check_No_Locks --
 954    --------------------
 955
 956    function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
 957    begin
 958       return True;
 959    end Check_No_Locks;
 960
 961    ----------------------
 962    -- Environment_Task --
 963    ----------------------
 964
 965    function Environment_Task return Task_ID is
 966    begin
 967       return Environment_Task_ID;
 968    end Environment_Task;
 969
 970    -------------------------
 971    -- Lock_All_Tasks_List --
 972    -------------------------
 973
 974    procedure Lock_All_Tasks_List is
 975    begin
 976       Write_Lock (All_Tasks_L'Access);
 977    end Lock_All_Tasks_List;
 978
 979    ---------------------------
 980    -- Unlock_All_Tasks_List --
 981    ---------------------------
 982
 983    procedure Unlock_All_Tasks_List is
 984    begin
 985       Unlock (All_Tasks_L'Access);
 986    end Unlock_All_Tasks_List;
 987
 988    ------------------
 989    -- Suspend_Task --
 990    ------------------
 991
 992    function Suspend_Task
 993      (T           : ST.Task_ID;
 994       Thread_Self : Thread_Id) return Boolean is
 995    begin
 996       if T.Common.LL.Thread /= null_pthread
 997         and then T.Common.LL.Thread /= Thread_Self
 998       then
 999          return taskSuspend (T.Common.LL.Thread) = 0;
1000       else
1001          return True;
1002       end if;
1003    end Suspend_Task;
1004
1005    -----------------
1006    -- Resume_Task --
1007    -----------------
1008
1009    function Resume_Task
1010      (T           : ST.Task_ID;
1011       Thread_Self : Thread_Id) return Boolean is
1012    begin
1013       if T.Common.LL.Thread /= null_pthread
1014         and then T.Common.LL.Thread /= Thread_Self
1015       then
1016          return taskResume (T.Common.LL.Thread) = 0;
1017       else
1018          return True;
1019       end if;
1020    end Resume_Task;
1021
1022    ----------------
1023    -- Initialize --
1024    ----------------
1025
1026    procedure Initialize (Environment_Task : Task_ID) is
1027    begin
1028       Environment_Task_ID := Environment_Task;
1029
1030       --  Initialize the lock used to synchronize chain of all ATCBs.
1031
1032       Initialize_Lock (All_Tasks_L'Access, All_Tasks_Level);
1033
1034       Enter_Task (Environment_Task);
1035    end Initialize;
1036
1037 begin
1038    declare
1039       Result : Interfaces.C.int;
1040
1041    begin
1042       if Locking_Policy = 'C' then
1043          Mutex_Protocol := PTHREAD_PRIO_PROTECT;
1044       else
1045          --  We default to VxWorks native priority inheritence
1046          --  and inversion safe mutexes with no ceiling checks.
1047          Mutex_Protocol := PTHREAD_PRIO_INHERIT;
1048       end if;
1049
1050       if Time_Slice_Val > 0 then
1051          Result := pthread_sched_rr_set_interval
1052            (Interfaces.C.int (Time_Slice_Val));
1053       end if;
1054
1055       --  Prepare the set of signals that should unblocked in all tasks
1056
1057       Result := sigemptyset (Unblocked_Signal_Mask'Access);
1058       pragma Assert (Result = 0);
1059
1060       for J in Interrupt_Management.Interrupt_ID loop
1061          if Interrupt_Management.Keep_Unmasked (J) then
1062             Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1063             pragma Assert (Result = 0);
1064          end if;
1065       end loop;
1066
1067       Result := pthread_key_create (ATCB_Key'Access, null);
1068       pragma Assert (Result = 0);
1069
1070       Result := taskVarAdd (getpid, Stack_Limit'Access);
1071       pragma Assert (Result = 0);
1072    end;
1073 end System.Task_Primitives.Operations;