gcc/ada/s-taprop-hpux-dce.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT 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 --         Copyright (C) 1992-2005, 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- --
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  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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  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.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is a HP-UX DCE threads (HPUX 10) version of this package
  35
  36 --  This package contains all the GNULL primitives that interface directly
  37 --  with the underlying OS.
  38
  39 pragma Polling (Off);
  40 --  Turn off polling, we do not want ATC polling to take place during
  41 --  tasking operations. It causes infinite loops and other problems.
  42
  43 with System.Tasking.Debug;
  44 --  used for Known_Tasks
  45
  46 with System.Interrupt_Management;
  47 --  used for Keep_Unmasked
  48 --           Abort_Task_Interrupt
  49 --           Interrupt_ID
  50
  51 pragma Warnings (Off);
  52 with System.Interrupt_Management.Operations;
  53 --  used for Set_Interrupt_Mask
  54 --           All_Tasks_Mask
  55 pragma Elaborate_All (System.Interrupt_Management.Operations);
  56
  57 pragma Warnings (On);
  58
  59 with System.OS_Primitives;
  60 --  used for Delay_Modes
  61
  62 with Interfaces.C;
  63 --  used for int
  64 --           size_t
  65
  66 with System.Parameters;
  67 --  used for Size_Type
  68
  69 with System.Task_Primitives.Interrupt_Operations;
  70 --  used for Get_Interrupt_ID
  71
  72 with Unchecked_Conversion;
  73 with Unchecked_Deallocation;
  74
  75 package body System.Task_Primitives.Operations is
  76
  77    use System.Tasking.Debug;
  78    use System.Tasking;
  79    use Interfaces.C;
  80    use System.OS_Interface;
  81    use System.Parameters;
  82    use System.OS_Primitives;
  83
  84    package PIO renames System.Task_Primitives.Interrupt_Operations;
  85
  86    ----------------
  87    -- Local Data --
  88    ----------------
  89
  90    --  The followings are logically constants, but need to be initialized
  91    --  at run time.
  92
  93    Single_RTS_Lock : aliased RTS_Lock;
  94    --  This is a lock to allow only one thread of control in the RTS at
  95    --  a time; it is used to execute in mutual exclusion from all other tasks.
  96    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
  97
  98    ATCB_Key : aliased pthread_key_t;
  99    --  Key used to find the Ada Task_Id associated with a thread
 100
 101    Environment_Task_Id : Task_Id;
 102    --  A variable to hold Task_Id for the environment task
 103
 104    Unblocked_Signal_Mask : aliased sigset_t;
 105    --  The set of signals that should unblocked in all tasks
 106
 107    Time_Slice_Val : Integer;
 108    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 109
 110    Dispatching_Policy : Character;
 111    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 112
 113    --  Note: the reason that Locking_Policy is not needed is that this
 114    --  is not implemented for DCE threads. The HPUX 10 port is at this
 115    --  stage considered dead, and no further work is planned on it.
 116
 117    Foreign_Task_Elaborated : aliased Boolean := True;
 118    --  Used to identified fake tasks (i.e., non-Ada Threads)
 119
 120    --------------------
 121    -- Local Packages --
 122    --------------------
 123
 124    package Specific is
 125
 126       procedure Initialize (Environment_Task : Task_Id);
 127       pragma Inline (Initialize);
 128       --  Initialize various data needed by this package
 129
 130       function Is_Valid_Task return Boolean;
 131       pragma Inline (Is_Valid_Task);
 132       --  Does the executing thread have a TCB?
 133
 134       procedure Set (Self_Id : Task_Id);
 135       pragma Inline (Set);
 136       --  Set the self id for the current task
 137
 138       function Self return Task_Id;
 139       pragma Inline (Self);
 140       --  Return a pointer to the Ada Task Control Block of the calling task
 141
 142    end Specific;
 143
 144    package body Specific is separate;
 145    --  The body of this package is target specific
 146
 147    ---------------------------------
 148    -- Support for foreign threads --
 149    ---------------------------------
 150
 151    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 152    --  Allocate and Initialize a new ATCB for the current Thread
 153
 154    function Register_Foreign_Thread
 155      (Thread : Thread_Id) return Task_Id is separate;
 156
 157    -----------------------
 158    -- Local Subprograms --
 159    -----------------------
 160
 161    procedure Abort_Handler (Sig : Signal);
 162
 163    function To_Address is new Unchecked_Conversion (Task_Id, System.Address);
 164
 165    -------------------
 166    -- Abort_Handler --
 167    -------------------
 168
 169    procedure Abort_Handler (Sig : Signal) is
 170       pragma Unreferenced (Sig);
 171
 172       Self_Id : constant Task_Id := Self;
 173       Result  : Interfaces.C.int;
 174       Old_Set : aliased sigset_t;
 175
 176    begin
 177       if Self_Id.Deferral_Level = 0
 178         and then Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level and then
 179         not Self_Id.Aborting
 180       then
 181          Self_Id.Aborting := True;
 182
 183          --  Make sure signals used for RTS internal purpose are unmasked
 184
 185          Result := pthread_sigmask (SIG_UNBLOCK,
 186            Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
 187          pragma Assert (Result = 0);
 188
 189          raise Standard'Abort_Signal;
 190       end if;
 191    end Abort_Handler;
 192
 193    -----------------
 194    -- Stack_Guard --
 195    -----------------
 196
 197    --  The underlying thread system sets a guard page at the
 198    --  bottom of a thread stack, so nothing is needed.
 199    --  ??? Check the comment above
 200
 201    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 202       pragma Unreferenced (T, On);
 203    begin
 204       null;
 205    end Stack_Guard;
 206
 207    -------------------
 208    -- Get_Thread_Id --
 209    -------------------
 210
 211    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 212    begin
 213       return T.Common.LL.Thread;
 214    end Get_Thread_Id;
 215
 216    ----------
 217    -- Self --
 218    ----------
 219
 220    function Self return Task_Id renames Specific.Self;
 221
 222    ---------------------
 223    -- Initialize_Lock --
 224    ---------------------
 225
 226    --  Note: mutexes and cond_variables needed per-task basis are
 227    --        initialized in Initialize_TCB and the Storage_Error is
 228    --        handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
 229    --        used in RTS is initialized before any status change of RTS.
 230    --        Therefore rasing Storage_Error in the following routines
 231    --        should be able to be handled safely.
 232
 233    procedure Initialize_Lock
 234      (Prio : System.Any_Priority;
 235       L    : access Lock)
 236    is
 237       Attributes : aliased pthread_mutexattr_t;
 238       Result     : Interfaces.C.int;
 239
 240    begin
 241       Result := pthread_mutexattr_init (Attributes'Access);
 242       pragma Assert (Result = 0 or else Result = ENOMEM);
 243
 244       if Result = ENOMEM then
 245          raise Storage_Error;
 246       end if;
 247
 248       L.Priority := Prio;
 249
 250       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 251       pragma Assert (Result = 0 or else Result = ENOMEM);
 252
 253       if Result = ENOMEM then
 254          raise Storage_Error;
 255       end if;
 256
 257       Result := pthread_mutexattr_destroy (Attributes'Access);
 258       pragma Assert (Result = 0);
 259    end Initialize_Lock;
 260
 261    procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
 262       pragma Unreferenced (Level);
 263
 264       Attributes : aliased pthread_mutexattr_t;
 265       Result     : Interfaces.C.int;
 266
 267    begin
 268       Result := pthread_mutexattr_init (Attributes'Access);
 269       pragma Assert (Result = 0 or else Result = ENOMEM);
 270
 271       if Result = ENOMEM then
 272          raise Storage_Error;
 273       end if;
 274
 275       Result := pthread_mutex_init (L, Attributes'Access);
 276
 277       pragma Assert (Result = 0 or else Result = ENOMEM);
 278
 279       if Result = ENOMEM then
 280          raise Storage_Error;
 281       end if;
 282
 283       Result := pthread_mutexattr_destroy (Attributes'Access);
 284       pragma Assert (Result = 0);
 285    end Initialize_Lock;
 286
 287    -------------------
 288    -- Finalize_Lock --
 289    -------------------
 290
 291    procedure Finalize_Lock (L : access Lock) is
 292       Result : Interfaces.C.int;
 293    begin
 294       Result := pthread_mutex_destroy (L.L'Access);
 295       pragma Assert (Result = 0);
 296    end Finalize_Lock;
 297
 298    procedure Finalize_Lock (L : access RTS_Lock) is
 299       Result : Interfaces.C.int;
 300    begin
 301       Result := pthread_mutex_destroy (L);
 302       pragma Assert (Result = 0);
 303    end Finalize_Lock;
 304
 305    ----------------
 306    -- Write_Lock --
 307    ----------------
 308
 309    procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 310       Result : Interfaces.C.int;
 311
 312    begin
 313       L.Owner_Priority := Get_Priority (Self);
 314
 315       if L.Priority < L.Owner_Priority then
 316          Ceiling_Violation := True;
 317          return;
 318       end if;
 319
 320       Result := pthread_mutex_lock (L.L'Access);
 321       pragma Assert (Result = 0);
 322       Ceiling_Violation := False;
 323    end Write_Lock;
 324
 325    procedure Write_Lock
 326      (L : access RTS_Lock; Global_Lock : Boolean := False)
 327    is
 328       Result : Interfaces.C.int;
 329    begin
 330       if not Single_Lock or else Global_Lock then
 331          Result := pthread_mutex_lock (L);
 332          pragma Assert (Result = 0);
 333       end if;
 334    end Write_Lock;
 335
 336    procedure Write_Lock (T : Task_Id) is
 337       Result : Interfaces.C.int;
 338    begin
 339       if not Single_Lock then
 340          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 341          pragma Assert (Result = 0);
 342       end if;
 343    end Write_Lock;
 344
 345    ---------------
 346    -- Read_Lock --
 347    ---------------
 348
 349    procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 350    begin
 351       Write_Lock (L, Ceiling_Violation);
 352    end Read_Lock;
 353
 354    ------------
 355    -- Unlock --
 356    ------------
 357
 358    procedure Unlock (L : access Lock) is
 359       Result : Interfaces.C.int;
 360    begin
 361       Result := pthread_mutex_unlock (L.L'Access);
 362       pragma Assert (Result = 0);
 363    end Unlock;
 364
 365    procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
 366       Result : Interfaces.C.int;
 367    begin
 368       if not Single_Lock or else Global_Lock then
 369          Result := pthread_mutex_unlock (L);
 370          pragma Assert (Result = 0);
 371       end if;
 372    end Unlock;
 373
 374    procedure Unlock (T : Task_Id) is
 375       Result : Interfaces.C.int;
 376    begin
 377       if not Single_Lock then
 378          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 379          pragma Assert (Result = 0);
 380       end if;
 381    end Unlock;
 382
 383    -----------
 384    -- Sleep --
 385    -----------
 386
 387    procedure Sleep
 388      (Self_ID : Task_Id;
 389       Reason  : System.Tasking.Task_States)
 390    is
 391       pragma Unreferenced (Reason);
 392
 393       Result : Interfaces.C.int;
 394    begin
 395       if Single_Lock then
 396          Result := pthread_cond_wait
 397            (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 398       else
 399          Result := pthread_cond_wait
 400            (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 401       end if;
 402
 403       --  EINTR is not considered a failure
 404
 405       pragma Assert (Result = 0 or else Result = EINTR);
 406    end Sleep;
 407
 408    -----------------
 409    -- Timed_Sleep --
 410    -----------------
 411
 412    procedure Timed_Sleep
 413      (Self_ID  : Task_Id;
 414       Time     : Duration;
 415       Mode     : ST.Delay_Modes;
 416       Reason   : System.Tasking.Task_States;
 417       Timedout : out Boolean;
 418       Yielded  : out Boolean)
 419    is
 420       pragma Unreferenced (Reason);
 421
 422       Check_Time : constant Duration := Monotonic_Clock;
 423       Abs_Time   : Duration;
 424       Request    : aliased timespec;
 425       Result     : Interfaces.C.int;
 426
 427    begin
 428       Timedout := True;
 429       Yielded := False;
 430
 431       if Mode = Relative then
 432          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 433       else
 434          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 435       end if;
 436
 437       if Abs_Time > Check_Time then
 438          Request := To_Timespec (Abs_Time);
 439
 440          loop
 441             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 442               or else Self_ID.Pending_Priority_Change;
 443
 444             if Single_Lock then
 445                Result := pthread_cond_timedwait
 446                  (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
 447                   Request'Access);
 448
 449             else
 450                Result := pthread_cond_timedwait
 451                  (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
 452                   Request'Access);
 453             end if;
 454
 455             exit when Abs_Time <= Monotonic_Clock;
 456
 457             if Result = 0 or Result = EINTR then
 458
 459                --  Somebody may have called Wakeup for us
 460
 461                Timedout := False;
 462                exit;
 463             end if;
 464
 465             pragma Assert (Result = ETIMEDOUT);
 466          end loop;
 467       end if;
 468    end Timed_Sleep;
 469
 470    -----------------
 471    -- Timed_Delay --
 472    -----------------
 473
 474    procedure Timed_Delay
 475      (Self_ID  : Task_Id;
 476       Time     : Duration;
 477       Mode     : ST.Delay_Modes)
 478    is
 479       Check_Time : constant Duration := Monotonic_Clock;
 480       Abs_Time   : Duration;
 481       Request    : aliased timespec;
 482       Result     : Interfaces.C.int;
 483
 484    begin
 485       if Single_Lock then
 486          Lock_RTS;
 487       end if;
 488
 489       Write_Lock (Self_ID);
 490
 491       if Mode = Relative then
 492          Abs_Time := Time + Check_Time;
 493       else
 494          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 495       end if;
 496
 497       if Abs_Time > Check_Time then
 498          Request := To_Timespec (Abs_Time);
 499          Self_ID.Common.State := Delay_Sleep;
 500
 501          loop
 502             if Self_ID.Pending_Priority_Change then
 503                Self_ID.Pending_Priority_Change := False;
 504                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 505                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 506             end if;
 507
 508             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 509
 510             if Single_Lock then
 511                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 512                  Single_RTS_Lock'Access, Request'Access);
 513             else
 514                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 515                  Self_ID.Common.LL.L'Access, Request'Access);
 516             end if;
 517
 518             exit when Abs_Time <= Monotonic_Clock;
 519
 520             pragma Assert (Result = 0 or else
 521               Result = ETIMEDOUT or else
 522               Result = EINTR);
 523          end loop;
 524
 525          Self_ID.Common.State := Runnable;
 526       end if;
 527
 528       Unlock (Self_ID);
 529
 530       if Single_Lock then
 531          Unlock_RTS;
 532       end if;
 533
 534       Result := sched_yield;
 535    end Timed_Delay;
 536
 537    ---------------------
 538    -- Monotonic_Clock --
 539    ---------------------
 540
 541    function Monotonic_Clock return Duration is
 542       TS     : aliased timespec;
 543       Result : Interfaces.C.int;
 544    begin
 545       Result := Clock_Gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 546       pragma Assert (Result = 0);
 547       return To_Duration (TS);
 548    end Monotonic_Clock;
 549
 550    -------------------
 551    -- RT_Resolution --
 552    -------------------
 553
 554    function RT_Resolution return Duration is
 555    begin
 556       return 10#1.0#E-6;
 557    end RT_Resolution;
 558
 559    ------------
 560    -- Wakeup --
 561    ------------
 562
 563    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 564       pragma Unreferenced (Reason);
 565
 566       Result : Interfaces.C.int;
 567
 568    begin
 569       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 570       pragma Assert (Result = 0);
 571    end Wakeup;
 572
 573    -----------
 574    -- Yield --
 575    -----------
 576
 577    procedure Yield (Do_Yield : Boolean := True) is
 578       Result : Interfaces.C.int;
 579       pragma Unreferenced (Result);
 580    begin
 581       if Do_Yield then
 582          Result := sched_yield;
 583       end if;
 584    end Yield;
 585
 586    ------------------
 587    -- Set_Priority --
 588    ------------------
 589
 590    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 591    pragma Atomic_Components (Prio_Array_Type);
 592
 593    Prio_Array : Prio_Array_Type;
 594    --  Global array containing the id of the currently running task for
 595    --  each priority.
 596    --
 597    --  Note: we assume that we are on a single processor with run-til-blocked
 598    --  scheduling.
 599
 600    procedure Set_Priority
 601      (T                   : Task_Id;
 602       Prio                : System.Any_Priority;
 603       Loss_Of_Inheritance : Boolean := False)
 604    is
 605       Result     : Interfaces.C.int;
 606       Array_Item : Integer;
 607       Param      : aliased struct_sched_param;
 608
 609    begin
 610       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 611
 612       if Time_Slice_Val > 0 then
 613          Result := pthread_setschedparam
 614            (T.Common.LL.Thread, SCHED_RR, Param'Access);
 615
 616       elsif Dispatching_Policy = 'F' or else Time_Slice_Val = 0 then
 617          Result := pthread_setschedparam
 618            (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 619
 620       else
 621          Result := pthread_setschedparam
 622            (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 623       end if;
 624
 625       pragma Assert (Result = 0);
 626
 627       if Dispatching_Policy = 'F' then
 628
 629          --  Annex D requirement [RM D.2.2 par. 9]:
 630          --    If the task drops its priority due to the loss of inherited
 631          --    priority, it is added at the head of the ready queue for its
 632          --    new active priority.
 633
 634          if Loss_Of_Inheritance
 635            and then Prio < T.Common.Current_Priority
 636          then
 637             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 638             Prio_Array (T.Common.Base_Priority) := Array_Item;
 639
 640             loop
 641                --  Let some processes a chance to arrive
 642
 643                Yield;
 644
 645                --  Then wait for our turn to proceed
 646
 647                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 648                  or else Prio_Array (T.Common.Base_Priority) = 1;
 649             end loop;
 650
 651             Prio_Array (T.Common.Base_Priority) :=
 652               Prio_Array (T.Common.Base_Priority) - 1;
 653          end if;
 654       end if;
 655
 656       T.Common.Current_Priority := Prio;
 657    end Set_Priority;
 658
 659    ------------------
 660    -- Get_Priority --
 661    ------------------
 662
 663    function Get_Priority (T : Task_Id) return System.Any_Priority is
 664    begin
 665       return T.Common.Current_Priority;
 666    end Get_Priority;
 667
 668    ----------------
 669    -- Enter_Task --
 670    ----------------
 671
 672    procedure Enter_Task (Self_ID : Task_Id) is
 673    begin
 674       Self_ID.Common.LL.Thread := pthread_self;
 675       Specific.Set (Self_ID);
 676
 677       Lock_RTS;
 678
 679       for J in Known_Tasks'Range loop
 680          if Known_Tasks (J) = null then
 681             Known_Tasks (J) := Self_ID;
 682             Self_ID.Known_Tasks_Index := J;
 683             exit;
 684          end if;
 685       end loop;
 686
 687       Unlock_RTS;
 688    end Enter_Task;
 689
 690    --------------
 691    -- New_ATCB --
 692    --------------
 693
 694    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 695    begin
 696       return new Ada_Task_Control_Block (Entry_Num);
 697    end New_ATCB;
 698
 699    -------------------
 700    -- Is_Valid_Task --
 701    -------------------
 702
 703    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 704
 705    -----------------------------
 706    -- Register_Foreign_Thread --
 707    -----------------------------
 708
 709    function Register_Foreign_Thread return Task_Id is
 710    begin
 711       if Is_Valid_Task then
 712          return Self;
 713       else
 714          return Register_Foreign_Thread (pthread_self);
 715       end if;
 716    end Register_Foreign_Thread;
 717
 718    --------------------
 719    -- Initialize_TCB --
 720    --------------------
 721
 722    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 723       Mutex_Attr : aliased pthread_mutexattr_t;
 724       Result     : Interfaces.C.int;
 725       Cond_Attr  : aliased pthread_condattr_t;
 726
 727    begin
 728       if not Single_Lock then
 729          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 730          pragma Assert (Result = 0 or else Result = ENOMEM);
 731
 732          if Result = 0 then
 733             Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 734               Mutex_Attr'Access);
 735             pragma Assert (Result = 0 or else Result = ENOMEM);
 736          end if;
 737
 738          if Result /= 0 then
 739             Succeeded := False;
 740             return;
 741          end if;
 742
 743          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 744          pragma Assert (Result = 0);
 745       end if;
 746
 747       Result := pthread_condattr_init (Cond_Attr'Access);
 748       pragma Assert (Result = 0 or else Result = ENOMEM);
 749
 750       if Result = 0 then
 751          Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 752            Cond_Attr'Access);
 753          pragma Assert (Result = 0 or else Result = ENOMEM);
 754       end if;
 755
 756       if Result = 0 then
 757          Succeeded := True;
 758       else
 759          if not Single_Lock then
 760             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 761             pragma Assert (Result = 0);
 762          end if;
 763
 764          Succeeded := False;
 765       end if;
 766
 767       Result := pthread_condattr_destroy (Cond_Attr'Access);
 768       pragma Assert (Result = 0);
 769    end Initialize_TCB;
 770
 771    -----------------
 772    -- Create_Task --
 773    -----------------
 774
 775    procedure Create_Task
 776      (T          : Task_Id;
 777       Wrapper    : System.Address;
 778       Stack_Size : System.Parameters.Size_Type;
 779       Priority   : System.Any_Priority;
 780       Succeeded  : out Boolean)
 781    is
 782       Attributes          : aliased pthread_attr_t;
 783       Adjusted_Stack_Size : Interfaces.C.size_t;
 784       Result              : Interfaces.C.int;
 785
 786       function Thread_Body_Access is new
 787         Unchecked_Conversion (System.Address, Thread_Body);
 788
 789    begin
 790       if Stack_Size = Unspecified_Size then
 791          Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
 792
 793       elsif Stack_Size < Minimum_Stack_Size then
 794          Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
 795
 796       else
 797          Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
 798       end if;
 799
 800       Result := pthread_attr_init (Attributes'Access);
 801       pragma Assert (Result = 0 or else Result = ENOMEM);
 802
 803       if Result /= 0 then
 804          Succeeded := False;
 805          return;
 806       end if;
 807
 808       Result := pthread_attr_setstacksize
 809         (Attributes'Access, Adjusted_Stack_Size);
 810       pragma Assert (Result = 0);
 811
 812       --  Since the initial signal mask of a thread is inherited from the
 813       --  creator, and the Environment task has all its signals masked, we
 814       --  do not need to manipulate caller's signal mask at this point.
 815       --  All tasks in RTS will have All_Tasks_Mask initially.
 816
 817       Result := pthread_create
 818         (T.Common.LL.Thread'Access,
 819          Attributes'Access,
 820          Thread_Body_Access (Wrapper),
 821          To_Address (T));
 822       pragma Assert (Result = 0 or else Result = EAGAIN);
 823
 824       Succeeded := Result = 0;
 825
 826       pthread_detach (T.Common.LL.Thread'Access);
 827       --  Detach the thread using pthread_detach, sinc DCE threads do not have
 828       --  pthread_attr_set_detachstate.
 829
 830       Result := pthread_attr_destroy (Attributes'Access);
 831       pragma Assert (Result = 0);
 832
 833       Set_Priority (T, Priority);
 834    end Create_Task;
 835
 836    ------------------
 837    -- Finalize_TCB --
 838    ------------------
 839
 840    procedure Finalize_TCB (T : Task_Id) is
 841       Result  : Interfaces.C.int;
 842       Tmp     : Task_Id := T;
 843       Is_Self : constant Boolean := T = Self;
 844
 845       procedure Free is new
 846         Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 847
 848    begin
 849       if not Single_Lock then
 850          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 851          pragma Assert (Result = 0);
 852       end if;
 853
 854       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 855       pragma Assert (Result = 0);
 856
 857       if T.Known_Tasks_Index /= -1 then
 858          Known_Tasks (T.Known_Tasks_Index) := null;
 859       end if;
 860
 861       Free (Tmp);
 862
 863       if Is_Self then
 864          Specific.Set (null);
 865       end if;
 866    end Finalize_TCB;
 867
 868    ---------------
 869    -- Exit_Task --
 870    ---------------
 871
 872    procedure Exit_Task is
 873    begin
 874       Specific.Set (null);
 875    end Exit_Task;
 876
 877    ----------------
 878    -- Abort_Task --
 879    ----------------
 880
 881    procedure Abort_Task (T : Task_Id) is
 882    begin
 883       --
 884       --  Interrupt Server_Tasks may be waiting on an "event" flag (signal)
 885       --
 886       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 887          System.Interrupt_Management.Operations.Interrupt_Self_Process
 888            (System.Interrupt_Management.Interrupt_ID
 889              (PIO.Get_Interrupt_ID (T)));
 890       end if;
 891    end Abort_Task;
 892
 893    ----------------
 894    -- Initialize --
 895    ----------------
 896
 897    procedure Initialize (S : in out Suspension_Object) is
 898       Mutex_Attr : aliased pthread_mutexattr_t;
 899       Cond_Attr  : aliased pthread_condattr_t;
 900       Result     : Interfaces.C.int;
 901    begin
 902       --  Initialize internal state. It is always initialized to False (ARM
 903       --  D.10 par. 6).
 904
 905       S.State := False;
 906       S.Waiting := False;
 907
 908       --  Initialize internal mutex
 909
 910       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 911       pragma Assert (Result = 0 or else Result = ENOMEM);
 912
 913       if Result = ENOMEM then
 914          raise Storage_Error;
 915       end if;
 916
 917       --  Initialize internal condition variable
 918
 919       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 920       pragma Assert (Result = 0 or else Result = ENOMEM);
 921
 922       if Result /= 0 then
 923          Result := pthread_mutex_destroy (S.L'Access);
 924          pragma Assert (Result = 0);
 925
 926          if Result = ENOMEM then
 927             raise Storage_Error;
 928          end if;
 929       end if;
 930    end Initialize;
 931
 932    --------------
 933    -- Finalize --
 934    --------------
 935
 936    procedure Finalize (S : in out Suspension_Object) is
 937       Result  : Interfaces.C.int;
 938    begin
 939       --  Destroy internal mutex
 940
 941       Result := pthread_mutex_destroy (S.L'Access);
 942       pragma Assert (Result = 0);
 943
 944       --  Destroy internal condition variable
 945
 946       Result := pthread_cond_destroy (S.CV'Access);
 947       pragma Assert (Result = 0);
 948    end Finalize;
 949
 950    -------------------
 951    -- Current_State --
 952    -------------------
 953
 954    function Current_State (S : Suspension_Object) return Boolean is
 955    begin
 956       --  We do not want to use lock on this read operation. State is marked
 957       --  as Atomic so that we ensure that the value retrieved is correct.
 958
 959       return S.State;
 960    end Current_State;
 961
 962    ---------------
 963    -- Set_False --
 964    ---------------
 965
 966    procedure Set_False (S : in out Suspension_Object) is
 967       Result  : Interfaces.C.int;
 968    begin
 969       Result := pthread_mutex_lock (S.L'Access);
 970       pragma Assert (Result = 0);
 971
 972       S.State := False;
 973
 974       Result := pthread_mutex_unlock (S.L'Access);
 975       pragma Assert (Result = 0);
 976    end Set_False;
 977
 978    --------------
 979    -- Set_True --
 980    --------------
 981
 982    procedure Set_True (S : in out Suspension_Object) is
 983       Result : Interfaces.C.int;
 984    begin
 985       Result := pthread_mutex_lock (S.L'Access);
 986       pragma Assert (Result = 0);
 987
 988       --  If there is already a task waiting on this suspension object then
 989       --  we resume it, leaving the state of the suspension object to False,
 990       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
 991       --  the state to True.
 992
 993       if S.Waiting then
 994          S.Waiting := False;
 995          S.State := False;
 996
 997          Result := pthread_cond_signal (S.CV'Access);
 998          pragma Assert (Result = 0);
 999       else
1000          S.State := True;
1001       end if;
1002
1003       Result := pthread_mutex_unlock (S.L'Access);
1004       pragma Assert (Result = 0);
1005    end Set_True;
1006
1007    ------------------------
1008    -- Suspend_Until_True --
1009    ------------------------
1010
1011    procedure Suspend_Until_True (S : in out Suspension_Object) is
1012       Result : Interfaces.C.int;
1013    begin
1014       Result := pthread_mutex_lock (S.L'Access);
1015       pragma Assert (Result = 0);
1016
1017       if S.Waiting then
1018          --  Program_Error must be raised upon calling Suspend_Until_True
1019          --  if another task is already waiting on that suspension object
1020          --  (ARM D.10 par. 10).
1021
1022          Result := pthread_mutex_unlock (S.L'Access);
1023          pragma Assert (Result = 0);
1024
1025          raise Program_Error;
1026       else
1027          --  Suspend the task if the state is False. Otherwise, the task
1028          --  continues its execution, and the state of the suspension object
1029          --  is set to False (ARM D.10 par. 9).
1030
1031          if S.State then
1032             S.State := False;
1033          else
1034             S.Waiting := True;
1035             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1036          end if;
1037       end if;
1038
1039       Result := pthread_mutex_unlock (S.L'Access);
1040       pragma Assert (Result = 0);
1041    end Suspend_Until_True;
1042
1043    ----------------
1044    -- Check_Exit --
1045    ----------------
1046
1047    --  Dummy version
1048
1049    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1050       pragma Unreferenced (Self_ID);
1051    begin
1052       return True;
1053    end Check_Exit;
1054
1055    --------------------
1056    -- Check_No_Locks --
1057    --------------------
1058
1059    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1060       pragma Unreferenced (Self_ID);
1061    begin
1062       return True;
1063    end Check_No_Locks;
1064
1065    ----------------------
1066    -- Environment_Task --
1067    ----------------------
1068
1069    function Environment_Task return Task_Id is
1070    begin
1071       return Environment_Task_Id;
1072    end Environment_Task;
1073
1074    --------------
1075    -- Lock_RTS --
1076    --------------
1077
1078    procedure Lock_RTS is
1079    begin
1080       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1081    end Lock_RTS;
1082
1083    ----------------
1084    -- Unlock_RTS --
1085    ----------------
1086
1087    procedure Unlock_RTS is
1088    begin
1089       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1090    end Unlock_RTS;
1091
1092    ------------------
1093    -- Suspend_Task --
1094    ------------------
1095
1096    function Suspend_Task
1097      (T           : ST.Task_Id;
1098       Thread_Self : Thread_Id) return Boolean
1099    is
1100       pragma Unreferenced (T);
1101       pragma Unreferenced (Thread_Self);
1102    begin
1103       return False;
1104    end Suspend_Task;
1105
1106    -----------------
1107    -- Resume_Task --
1108    -----------------
1109
1110    function Resume_Task
1111      (T           : ST.Task_Id;
1112       Thread_Self : Thread_Id) return Boolean
1113    is
1114       pragma Unreferenced (T);
1115       pragma Unreferenced (Thread_Self);
1116    begin
1117       return False;
1118    end Resume_Task;
1119
1120    ----------------
1121    -- Initialize --
1122    ----------------
1123
1124    procedure Initialize (Environment_Task : Task_Id) is
1125       act       : aliased struct_sigaction;
1126       old_act   : aliased struct_sigaction;
1127       Tmp_Set   : aliased sigset_t;
1128       Result    : Interfaces.C.int;
1129
1130       function State
1131         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1132       pragma Import (C, State, "__gnat_get_interrupt_state");
1133       --  Get interrupt state. Defined in a-init.c. The input argument is
1134       --  the interrupt number, and the result is one of the following:
1135
1136       Default : constant Character := 's';
1137       --    'n'   this interrupt not set by any Interrupt_State pragma
1138       --    'u'   Interrupt_State pragma set state to User
1139       --    'r'   Interrupt_State pragma set state to Runtime
1140       --    's'   Interrupt_State pragma set state to System (use "default"
1141       --           system handler)
1142
1143    begin
1144       Environment_Task_Id := Environment_Task;
1145
1146       Interrupt_Management.Initialize;
1147
1148       --  Initialize the lock used to synchronize chain of all ATCBs
1149
1150       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1151
1152       Specific.Initialize (Environment_Task);
1153
1154       Enter_Task (Environment_Task);
1155
1156       --  Install the abort-signal handler
1157
1158       if State (System.Interrupt_Management.Abort_Task_Interrupt)
1159                                                      /= Default
1160       then
1161          act.sa_flags := 0;
1162          act.sa_handler := Abort_Handler'Address;
1163
1164          Result := sigemptyset (Tmp_Set'Access);
1165          pragma Assert (Result = 0);
1166          act.sa_mask := Tmp_Set;
1167
1168          Result :=
1169            sigaction (
1170              Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1171              act'Unchecked_Access,
1172              old_act'Unchecked_Access);
1173          pragma Assert (Result = 0);
1174       end if;
1175    end Initialize;
1176
1177    --  NOTE: Unlike other pthread implementations, we do *not* mask all
1178    --  signals here since we handle signals using the process-wide primitive
1179    --  signal, rather than using sigthreadmask and sigwait. The reason of
1180    --  this difference is that sigwait doesn't work when some critical
1181    --  signals (SIGABRT, SIGPIPE) are masked.
1182
1183 end System.Task_Primitives.Operations;