gcc/ada/libgnarl/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) 1992-2019, 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
  32 --  This is a HP-UX DCE threads (HPUX 10) version of this package
  33
  34 --  This package contains all the GNULL primitives that interface directly with
  35 --  the underlying OS.
  36
  37 pragma Polling (Off);
  38 --  Turn off polling, we do not want ATC polling to take place during tasking
  39 --  operations. It causes infinite loops and other problems.
  40
  41 with Ada.Unchecked_Conversion;
  42
  43 with Interfaces.C;
  44
  45 with System.Tasking.Debug;
  46 with System.Interrupt_Management;
  47 with System.OS_Constants;
  48 with System.OS_Primitives;
  49 with System.Task_Primitives.Interrupt_Operations;
  50
  51 pragma Warnings (Off);
  52 with System.Interrupt_Management.Operations;
  53 pragma Elaborate_All (System.Interrupt_Management.Operations);
  54 pragma Warnings (On);
  55
  56 with System.Soft_Links;
  57 --  We use System.Soft_Links instead of System.Tasking.Initialization
  58 --  because the later is a higher level package that we shouldn't depend on.
  59 --  For example when using the restricted run time, it is replaced by
  60 --  System.Tasking.Restricted.Stages.
  61
  62 package body System.Task_Primitives.Operations is
  63
  64    package OSC renames System.OS_Constants;
  65    package SSL renames System.Soft_Links;
  66
  67    use System.Tasking.Debug;
  68    use System.Tasking;
  69    use Interfaces.C;
  70    use System.OS_Interface;
  71    use System.Parameters;
  72    use System.OS_Primitives;
  73
  74    package PIO renames System.Task_Primitives.Interrupt_Operations;
  75
  76    ----------------
  77    -- Local Data --
  78    ----------------
  79
  80    --  The followings are logically constants, but need to be initialized
  81    --  at run time.
  82
  83    Single_RTS_Lock : aliased RTS_Lock;
  84    --  This is a lock to allow only one thread of control in the RTS at
  85    --  a time; it is used to execute in mutual exclusion from all other tasks.
  86    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
  87
  88    Environment_Task_Id : Task_Id;
  89    --  A variable to hold Task_Id for the environment task
  90
  91    Unblocked_Signal_Mask : aliased sigset_t;
  92    --  The set of signals that should unblocked in all tasks
  93
  94    Time_Slice_Val : Integer;
  95    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
  96
  97    Dispatching_Policy : Character;
  98    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
  99
 100    --  Note: the reason that Locking_Policy is not needed is that this
 101    --  is not implemented for DCE threads. The HPUX 10 port is at this
 102    --  stage considered dead, and no further work is planned on it.
 103
 104    Foreign_Task_Elaborated : aliased Boolean := True;
 105    --  Used to identified fake tasks (i.e., non-Ada Threads)
 106
 107    --------------------
 108    -- Local Packages --
 109    --------------------
 110
 111    package Specific is
 112
 113       procedure Initialize (Environment_Task : Task_Id);
 114       pragma Inline (Initialize);
 115       --  Initialize various data needed by this package
 116
 117       function Is_Valid_Task return Boolean;
 118       pragma Inline (Is_Valid_Task);
 119       --  Does the executing thread have a TCB?
 120
 121       procedure Set (Self_Id : Task_Id);
 122       pragma Inline (Set);
 123       --  Set the self id for the current task
 124
 125       function Self return Task_Id;
 126       pragma Inline (Self);
 127       --  Return a pointer to the Ada Task Control Block of the calling task
 128
 129    end Specific;
 130
 131    package body Specific is separate;
 132    --  The body of this package is target specific
 133
 134    ----------------------------------
 135    -- ATCB allocation/deallocation --
 136    ----------------------------------
 137
 138    package body ATCB_Allocation is separate;
 139    --  The body of this package is shared across several targets
 140
 141    ---------------------------------
 142    -- Support for foreign threads --
 143    ---------------------------------
 144
 145    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 146    --  Allocate and Initialize a new ATCB for the current Thread
 147
 148    function Register_Foreign_Thread
 149      (Thread : Thread_Id) return Task_Id is separate;
 150
 151    -----------------------
 152    -- Local Subprograms --
 153    -----------------------
 154
 155    procedure Abort_Handler (Sig : Signal);
 156
 157    function To_Address is
 158      new Ada.Unchecked_Conversion (Task_Id, System.Address);
 159
 160    -------------------
 161    -- Abort_Handler --
 162    -------------------
 163
 164    procedure Abort_Handler (Sig : Signal) is
 165       pragma Unreferenced (Sig);
 166
 167       Self_Id : constant Task_Id := Self;
 168       Result  : Interfaces.C.int;
 169       Old_Set : aliased sigset_t;
 170
 171    begin
 172       if Self_Id.Deferral_Level = 0
 173         and then Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level
 174         and then not Self_Id.Aborting
 175       then
 176          Self_Id.Aborting := True;
 177
 178          --  Make sure signals used for RTS internal purpose are unmasked
 179
 180          Result :=
 181            pthread_sigmask
 182              (SIG_UNBLOCK,
 183               Unblocked_Signal_Mask'Access,
 184               Old_Set'Access);
 185          pragma Assert (Result = 0);
 186
 187          raise Standard'Abort_Signal;
 188       end if;
 189    end Abort_Handler;
 190
 191    -----------------
 192    -- Stack_Guard --
 193    -----------------
 194
 195    --  The underlying thread system sets a guard page at the bottom of a thread
 196    --  stack, so nothing is needed.
 197    --  ??? Check the comment above
 198
 199    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 200       pragma Unreferenced (T, On);
 201    begin
 202       null;
 203    end Stack_Guard;
 204
 205    -------------------
 206    -- Get_Thread_Id --
 207    -------------------
 208
 209    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 210    begin
 211       return T.Common.LL.Thread;
 212    end Get_Thread_Id;
 213
 214    ----------
 215    -- Self --
 216    ----------
 217
 218    function Self return Task_Id renames Specific.Self;
 219
 220    ---------------------
 221    -- Initialize_Lock --
 222    ---------------------
 223
 224    --  Note: mutexes and cond_variables needed per-task basis are initialized
 225    --  in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
 226    --  as RTS_Lock, Memory_Lock...) used in RTS is initialized before any
 227    --  status change of RTS. Therefore raising Storage_Error in the following
 228    --  routines should be able to be handled safely.
 229
 230    procedure Initialize_Lock
 231      (Prio : System.Any_Priority;
 232       L    : not null access Lock)
 233    is
 234       Attributes : aliased pthread_mutexattr_t;
 235       Result     : Interfaces.C.int;
 236
 237    begin
 238       Result := pthread_mutexattr_init (Attributes'Access);
 239       pragma Assert (Result = 0 or else Result = ENOMEM);
 240
 241       if Result = ENOMEM then
 242          raise Storage_Error;
 243       end if;
 244
 245       L.Priority := Prio;
 246
 247       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 248       pragma Assert (Result = 0 or else Result = ENOMEM);
 249
 250       if Result = ENOMEM then
 251          raise Storage_Error;
 252       end if;
 253
 254       Result := pthread_mutexattr_destroy (Attributes'Access);
 255       pragma Assert (Result = 0);
 256    end Initialize_Lock;
 257
 258    procedure Initialize_Lock
 259      (L     : not null access RTS_Lock;
 260       Level : Lock_Level)
 261    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 : not null 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 : not null 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
 310      (L                 : not null access Lock;
 311       Ceiling_Violation : out Boolean)
 312    is
 313       Result : Interfaces.C.int;
 314
 315    begin
 316       L.Owner_Priority := Get_Priority (Self);
 317
 318       if L.Priority < L.Owner_Priority then
 319          Ceiling_Violation := True;
 320          return;
 321       end if;
 322
 323       Result := pthread_mutex_lock (L.L'Access);
 324       pragma Assert (Result = 0);
 325       Ceiling_Violation := False;
 326    end Write_Lock;
 327
 328    procedure Write_Lock
 329      (L           : not null access RTS_Lock;
 330       Global_Lock : Boolean := False)
 331    is
 332       Result : Interfaces.C.int;
 333    begin
 334       if not Single_Lock or else Global_Lock then
 335          Result := pthread_mutex_lock (L);
 336          pragma Assert (Result = 0);
 337       end if;
 338    end Write_Lock;
 339
 340    procedure Write_Lock (T : Task_Id) is
 341       Result : Interfaces.C.int;
 342    begin
 343       if not Single_Lock then
 344          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 345          pragma Assert (Result = 0);
 346       end if;
 347    end Write_Lock;
 348
 349    ---------------
 350    -- Read_Lock --
 351    ---------------
 352
 353    procedure Read_Lock
 354      (L                 : not null access Lock;
 355       Ceiling_Violation : out Boolean)
 356    is
 357    begin
 358       Write_Lock (L, Ceiling_Violation);
 359    end Read_Lock;
 360
 361    ------------
 362    -- Unlock --
 363    ------------
 364
 365    procedure Unlock (L : not null access Lock) is
 366       Result : Interfaces.C.int;
 367    begin
 368       Result := pthread_mutex_unlock (L.L'Access);
 369       pragma Assert (Result = 0);
 370    end Unlock;
 371
 372    procedure Unlock
 373      (L           : not null access RTS_Lock;
 374       Global_Lock : Boolean := False)
 375    is
 376       Result : Interfaces.C.int;
 377    begin
 378       if not Single_Lock or else Global_Lock then
 379          Result := pthread_mutex_unlock (L);
 380          pragma Assert (Result = 0);
 381       end if;
 382    end Unlock;
 383
 384    procedure Unlock (T : Task_Id) is
 385       Result : Interfaces.C.int;
 386    begin
 387       if not Single_Lock then
 388          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 389          pragma Assert (Result = 0);
 390       end if;
 391    end Unlock;
 392
 393    -----------------
 394    -- Set_Ceiling --
 395    -----------------
 396
 397    --  Dynamic priority ceilings are not supported by the underlying system
 398
 399    procedure Set_Ceiling
 400      (L    : not null access Lock;
 401       Prio : System.Any_Priority)
 402    is
 403       pragma Unreferenced (L, Prio);
 404    begin
 405       null;
 406    end Set_Ceiling;
 407
 408    -----------
 409    -- Sleep --
 410    -----------
 411
 412    procedure Sleep
 413      (Self_ID : Task_Id;
 414       Reason  : System.Tasking.Task_States)
 415    is
 416       pragma Unreferenced (Reason);
 417
 418       Result : Interfaces.C.int;
 419
 420    begin
 421       Result :=
 422         pthread_cond_wait
 423           (cond  => Self_ID.Common.LL.CV'Access,
 424            mutex => (if Single_Lock
 425                      then Single_RTS_Lock'Access
 426                      else Self_ID.Common.LL.L'Access));
 427
 428       --  EINTR is not considered a failure
 429
 430       pragma Assert (Result = 0 or else Result = EINTR);
 431    end Sleep;
 432
 433    -----------------
 434    -- Timed_Sleep --
 435    -----------------
 436
 437    procedure Timed_Sleep
 438      (Self_ID  : Task_Id;
 439       Time     : Duration;
 440       Mode     : ST.Delay_Modes;
 441       Reason   : System.Tasking.Task_States;
 442       Timedout : out Boolean;
 443       Yielded  : out Boolean)
 444    is
 445       pragma Unreferenced (Reason);
 446
 447       Check_Time : constant Duration := Monotonic_Clock;
 448       Abs_Time   : Duration;
 449       Request    : aliased timespec;
 450       Result     : Interfaces.C.int;
 451
 452    begin
 453       Timedout := True;
 454       Yielded := False;
 455
 456       Abs_Time :=
 457         (if Mode = Relative
 458          then Duration'Min (Time, Max_Sensible_Delay) + Check_Time
 459          else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
 460
 461       if Abs_Time > Check_Time then
 462          Request := To_Timespec (Abs_Time);
 463
 464          loop
 465             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 466
 467             Result :=
 468               pthread_cond_timedwait
 469                 (cond    => Self_ID.Common.LL.CV'Access,
 470                  mutex   => (if Single_Lock
 471                              then Single_RTS_Lock'Access
 472                              else Self_ID.Common.LL.L'Access),
 473                  abstime => Request'Access);
 474
 475             exit when Abs_Time <= Monotonic_Clock;
 476
 477             if Result = 0 or Result = EINTR then
 478
 479                --  Somebody may have called Wakeup for us
 480
 481                Timedout := False;
 482                exit;
 483             end if;
 484
 485             pragma Assert (Result = ETIMEDOUT);
 486          end loop;
 487       end if;
 488    end Timed_Sleep;
 489
 490    -----------------
 491    -- Timed_Delay --
 492    -----------------
 493
 494    procedure Timed_Delay
 495      (Self_ID : Task_Id;
 496       Time    : Duration;
 497       Mode    : ST.Delay_Modes)
 498    is
 499       Check_Time : constant Duration := Monotonic_Clock;
 500       Abs_Time   : Duration;
 501       Request    : aliased timespec;
 502
 503       Result : Interfaces.C.int;
 504       pragma Warnings (Off, Result);
 505
 506    begin
 507       if Single_Lock then
 508          Lock_RTS;
 509       end if;
 510
 511       Write_Lock (Self_ID);
 512
 513       Abs_Time :=
 514         (if Mode = Relative
 515          then Time + Check_Time
 516          else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
 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             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 524
 525             Result :=
 526               pthread_cond_timedwait
 527                 (cond    => Self_ID.Common.LL.CV'Access,
 528                  mutex   => (if Single_Lock
 529                              then Single_RTS_Lock'Access
 530                              else Self_ID.Common.LL.L'Access),
 531                  abstime => Request'Access);
 532
 533             exit when Abs_Time <= Monotonic_Clock;
 534
 535             pragma Assert (Result = 0 or else
 536               Result = ETIMEDOUT or else
 537               Result = EINTR);
 538          end loop;
 539
 540          Self_ID.Common.State := Runnable;
 541       end if;
 542
 543       Unlock (Self_ID);
 544
 545       if Single_Lock then
 546          Unlock_RTS;
 547       end if;
 548
 549       Result := sched_yield;
 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 (OSC.CLOCK_RT_Ada, 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       pragma Unreferenced (Reason);
 580       Result : Interfaces.C.int;
 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       pragma Unreferenced (Result);
 593    begin
 594       if Do_Yield then
 595          Result := sched_yield;
 596       end if;
 597    end Yield;
 598
 599    ------------------
 600    -- Set_Priority --
 601    ------------------
 602
 603    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 604    pragma Atomic_Components (Prio_Array_Type);
 605
 606    Prio_Array : Prio_Array_Type;
 607    --  Global array containing the id of the currently running task for
 608    --  each priority.
 609    --
 610    --  Note: assume we are on single processor with run-til-blocked scheduling
 611
 612    procedure Set_Priority
 613      (T                   : Task_Id;
 614       Prio                : System.Any_Priority;
 615       Loss_Of_Inheritance : Boolean := False)
 616    is
 617       Result     : Interfaces.C.int;
 618       Array_Item : Integer;
 619       Param      : aliased struct_sched_param;
 620
 621       function Get_Policy (Prio : System.Any_Priority) return Character;
 622       pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 623       --  Get priority specific dispatching policy
 624
 625       Priority_Specific_Policy : constant Character := Get_Policy (Prio);
 626       --  Upper case first character of the policy name corresponding to the
 627       --  task as set by a Priority_Specific_Dispatching pragma.
 628
 629    begin
 630       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 631
 632       if Dispatching_Policy = 'R'
 633         or else Priority_Specific_Policy = 'R'
 634         or else Time_Slice_Val > 0
 635       then
 636          Result :=
 637            pthread_setschedparam
 638              (T.Common.LL.Thread, SCHED_RR, Param'Access);
 639
 640       elsif Dispatching_Policy = 'F'
 641         or else Priority_Specific_Policy = 'F'
 642         or else Time_Slice_Val = 0
 643       then
 644          Result :=
 645            pthread_setschedparam
 646              (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 647
 648       else
 649          Result :=
 650            pthread_setschedparam
 651              (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 652       end if;
 653
 654       pragma Assert (Result = 0);
 655
 656       if Dispatching_Policy = 'F' or else Priority_Specific_Policy = 'F' then
 657
 658          --  Annex D requirement [RM D.2.2 par. 9]:
 659          --    If the task drops its priority due to the loss of inherited
 660          --    priority, it is added at the head of the ready queue for its
 661          --    new active priority.
 662
 663          if Loss_Of_Inheritance
 664            and then Prio < T.Common.Current_Priority
 665          then
 666             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 667             Prio_Array (T.Common.Base_Priority) := Array_Item;
 668
 669             loop
 670                --  Let some processes a chance to arrive
 671
 672                Yield;
 673
 674                --  Then wait for our turn to proceed
 675
 676                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 677                  or else Prio_Array (T.Common.Base_Priority) = 1;
 678             end loop;
 679
 680             Prio_Array (T.Common.Base_Priority) :=
 681               Prio_Array (T.Common.Base_Priority) - 1;
 682          end if;
 683       end if;
 684
 685       T.Common.Current_Priority := Prio;
 686    end Set_Priority;
 687
 688    ------------------
 689    -- Get_Priority --
 690    ------------------
 691
 692    function Get_Priority (T : Task_Id) return System.Any_Priority is
 693    begin
 694       return T.Common.Current_Priority;
 695    end Get_Priority;
 696
 697    ----------------
 698    -- Enter_Task --
 699    ----------------
 700
 701    procedure Enter_Task (Self_ID : Task_Id) is
 702    begin
 703       Self_ID.Common.LL.Thread := pthread_self;
 704       Specific.Set (Self_ID);
 705    end Enter_Task;
 706
 707    -------------------
 708    -- Is_Valid_Task --
 709    -------------------
 710
 711    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 712
 713    -----------------------------
 714    -- Register_Foreign_Thread --
 715    -----------------------------
 716
 717    function Register_Foreign_Thread return Task_Id is
 718    begin
 719       if Is_Valid_Task then
 720          return Self;
 721       else
 722          return Register_Foreign_Thread (pthread_self);
 723       end if;
 724    end Register_Foreign_Thread;
 725
 726    --------------------
 727    -- Initialize_TCB --
 728    --------------------
 729
 730    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 731       Mutex_Attr : aliased pthread_mutexattr_t;
 732       Result     : Interfaces.C.int;
 733       Cond_Attr  : aliased pthread_condattr_t;
 734
 735    begin
 736       if not Single_Lock then
 737          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 738          pragma Assert (Result = 0 or else Result = ENOMEM);
 739
 740          if Result = 0 then
 741             Result :=
 742               pthread_mutex_init
 743                 (Self_ID.Common.LL.L'Access, Mutex_Attr'Access);
 744             pragma Assert (Result = 0 or else Result = ENOMEM);
 745          end if;
 746
 747          if Result /= 0 then
 748             Succeeded := False;
 749             return;
 750          end if;
 751
 752          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 753          pragma Assert (Result = 0);
 754       end if;
 755
 756       Result := pthread_condattr_init (Cond_Attr'Access);
 757       pragma Assert (Result = 0 or else Result = ENOMEM);
 758
 759       if Result = 0 then
 760          Result :=
 761            pthread_cond_init
 762              (Self_ID.Common.LL.CV'Access,
 763               Cond_Attr'Access);
 764          pragma Assert (Result = 0 or else Result = ENOMEM);
 765       end if;
 766
 767       if Result = 0 then
 768          Succeeded := True;
 769       else
 770          if not Single_Lock then
 771             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 772             pragma Assert (Result = 0);
 773          end if;
 774
 775          Succeeded := False;
 776       end if;
 777
 778       Result := pthread_condattr_destroy (Cond_Attr'Access);
 779       pragma Assert (Result = 0);
 780    end Initialize_TCB;
 781
 782    -----------------
 783    -- Create_Task --
 784    -----------------
 785
 786    procedure Create_Task
 787      (T          : Task_Id;
 788       Wrapper    : System.Address;
 789       Stack_Size : System.Parameters.Size_Type;
 790       Priority   : System.Any_Priority;
 791       Succeeded  : out Boolean)
 792    is
 793       Attributes : aliased pthread_attr_t;
 794       Result     : Interfaces.C.int;
 795
 796       function Thread_Body_Access is new
 797         Ada.Unchecked_Conversion (System.Address, Thread_Body);
 798
 799    begin
 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, Interfaces.C.size_t (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, since 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
 843    begin
 844       if not Single_Lock then
 845          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 846          pragma Assert (Result = 0);
 847       end if;
 848
 849       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 850       pragma Assert (Result = 0);
 851
 852       if T.Known_Tasks_Index /= -1 then
 853          Known_Tasks (T.Known_Tasks_Index) := null;
 854       end if;
 855
 856       ATCB_Allocation.Free_ATCB (T);
 857    end Finalize_TCB;
 858
 859    ---------------
 860    -- Exit_Task --
 861    ---------------
 862
 863    procedure Exit_Task is
 864    begin
 865       Specific.Set (null);
 866    end Exit_Task;
 867
 868    ----------------
 869    -- Abort_Task --
 870    ----------------
 871
 872    procedure Abort_Task (T : Task_Id) is
 873    begin
 874       --  Interrupt Server_Tasks may be waiting on an "event" flag (signal)
 875
 876       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 877          System.Interrupt_Management.Operations.Interrupt_Self_Process
 878            (PIO.Get_Interrupt_ID (T));
 879       end if;
 880    end Abort_Task;
 881
 882    ----------------
 883    -- Initialize --
 884    ----------------
 885
 886    procedure Initialize (S : in out Suspension_Object) is
 887       Mutex_Attr : aliased pthread_mutexattr_t;
 888       Cond_Attr  : aliased pthread_condattr_t;
 889       Result     : Interfaces.C.int;
 890    begin
 891       --  Initialize internal state (always to False (ARM D.10(6)))
 892
 893       S.State := False;
 894       S.Waiting := False;
 895
 896       --  Initialize internal mutex
 897
 898       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 899       pragma Assert (Result = 0 or else Result = ENOMEM);
 900
 901       if Result = ENOMEM then
 902          raise Storage_Error;
 903       end if;
 904
 905       --  Initialize internal condition variable
 906
 907       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 908       pragma Assert (Result = 0 or else Result = ENOMEM);
 909
 910       if Result /= 0 then
 911          Result := pthread_mutex_destroy (S.L'Access);
 912          pragma Assert (Result = 0);
 913
 914          if Result = ENOMEM then
 915             raise Storage_Error;
 916          end if;
 917       end if;
 918    end Initialize;
 919
 920    --------------
 921    -- Finalize --
 922    --------------
 923
 924    procedure Finalize (S : in out Suspension_Object) is
 925       Result  : Interfaces.C.int;
 926
 927    begin
 928       --  Destroy internal mutex
 929
 930       Result := pthread_mutex_destroy (S.L'Access);
 931       pragma Assert (Result = 0);
 932
 933       --  Destroy internal condition variable
 934
 935       Result := pthread_cond_destroy (S.CV'Access);
 936       pragma Assert (Result = 0);
 937    end Finalize;
 938
 939    -------------------
 940    -- Current_State --
 941    -------------------
 942
 943    function Current_State (S : Suspension_Object) return Boolean is
 944    begin
 945       --  We do not want to use lock on this read operation. State is marked
 946       --  as Atomic so that we ensure that the value retrieved is correct.
 947
 948       return S.State;
 949    end Current_State;
 950
 951    ---------------
 952    -- Set_False --
 953    ---------------
 954
 955    procedure Set_False (S : in out Suspension_Object) is
 956       Result  : Interfaces.C.int;
 957
 958    begin
 959       SSL.Abort_Defer.all;
 960
 961       Result := pthread_mutex_lock (S.L'Access);
 962       pragma Assert (Result = 0);
 963
 964       S.State := False;
 965
 966       Result := pthread_mutex_unlock (S.L'Access);
 967       pragma Assert (Result = 0);
 968
 969       SSL.Abort_Undefer.all;
 970    end Set_False;
 971
 972    --------------
 973    -- Set_True --
 974    --------------
 975
 976    procedure Set_True (S : in out Suspension_Object) is
 977       Result : Interfaces.C.int;
 978
 979    begin
 980       SSL.Abort_Defer.all;
 981
 982       Result := pthread_mutex_lock (S.L'Access);
 983       pragma Assert (Result = 0);
 984
 985       --  If there is already a task waiting on this suspension object then
 986       --  we resume it, leaving the state of the suspension object to False,
 987       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
 988       --  the state to True.
 989
 990       if S.Waiting then
 991          S.Waiting := False;
 992          S.State := False;
 993
 994          Result := pthread_cond_signal (S.CV'Access);
 995          pragma Assert (Result = 0);
 996
 997       else
 998          S.State := True;
 999       end if;
1000
1001       Result := pthread_mutex_unlock (S.L'Access);
1002       pragma Assert (Result = 0);
1003
1004       SSL.Abort_Undefer.all;
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
1014    begin
1015       SSL.Abort_Defer.all;
1016
1017       Result := pthread_mutex_lock (S.L'Access);
1018       pragma Assert (Result = 0);
1019
1020       if S.Waiting then
1021          --  Program_Error must be raised upon calling Suspend_Until_True
1022          --  if another task is already waiting on that suspension object
1023          --  (ARM D.10 par. 10).
1024
1025          Result := pthread_mutex_unlock (S.L'Access);
1026          pragma Assert (Result = 0);
1027
1028          SSL.Abort_Undefer.all;
1029
1030          raise Program_Error;
1031       else
1032          --  Suspend the task if the state is False. Otherwise, the task
1033          --  continues its execution, and the state of the suspension object
1034          --  is set to False (ARM D.10 par. 9).
1035
1036          if S.State then
1037             S.State := False;
1038          else
1039             S.Waiting := True;
1040
1041             loop
1042                --  Loop in case pthread_cond_wait returns earlier than expected
1043                --  (e.g. in case of EINTR caused by a signal).
1044
1045                Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1046                pragma Assert (Result = 0 or else Result = EINTR);
1047
1048                exit when not S.Waiting;
1049             end loop;
1050          end if;
1051
1052          Result := pthread_mutex_unlock (S.L'Access);
1053          pragma Assert (Result = 0);
1054
1055          SSL.Abort_Undefer.all;
1056       end if;
1057    end Suspend_Until_True;
1058
1059    ----------------
1060    -- Check_Exit --
1061    ----------------
1062
1063    --  Dummy version
1064
1065    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1066       pragma Unreferenced (Self_ID);
1067    begin
1068       return True;
1069    end Check_Exit;
1070
1071    --------------------
1072    -- Check_No_Locks --
1073    --------------------
1074
1075    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1076       pragma Unreferenced (Self_ID);
1077    begin
1078       return True;
1079    end Check_No_Locks;
1080
1081    ----------------------
1082    -- Environment_Task --
1083    ----------------------
1084
1085    function Environment_Task return Task_Id is
1086    begin
1087       return Environment_Task_Id;
1088    end Environment_Task;
1089
1090    --------------
1091    -- Lock_RTS --
1092    --------------
1093
1094    procedure Lock_RTS is
1095    begin
1096       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1097    end Lock_RTS;
1098
1099    ----------------
1100    -- Unlock_RTS --
1101    ----------------
1102
1103    procedure Unlock_RTS is
1104    begin
1105       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1106    end Unlock_RTS;
1107
1108    ------------------
1109    -- Suspend_Task --
1110    ------------------
1111
1112    function Suspend_Task
1113      (T           : ST.Task_Id;
1114       Thread_Self : Thread_Id) return Boolean
1115    is
1116       pragma Unreferenced (T);
1117       pragma Unreferenced (Thread_Self);
1118    begin
1119       return False;
1120    end Suspend_Task;
1121
1122    -----------------
1123    -- Resume_Task --
1124    -----------------
1125
1126    function Resume_Task
1127      (T           : ST.Task_Id;
1128       Thread_Self : Thread_Id) return Boolean
1129    is
1130       pragma Unreferenced (T);
1131       pragma Unreferenced (Thread_Self);
1132    begin
1133       return False;
1134    end Resume_Task;
1135
1136    --------------------
1137    -- Stop_All_Tasks --
1138    --------------------
1139
1140    procedure Stop_All_Tasks is
1141    begin
1142       null;
1143    end Stop_All_Tasks;
1144
1145    ---------------
1146    -- Stop_Task --
1147    ---------------
1148
1149    function Stop_Task (T : ST.Task_Id) return Boolean is
1150       pragma Unreferenced (T);
1151    begin
1152       return False;
1153    end Stop_Task;
1154
1155    -------------------
1156    -- Continue_Task --
1157    -------------------
1158
1159    function Continue_Task (T : ST.Task_Id) return Boolean is
1160       pragma Unreferenced (T);
1161    begin
1162       return False;
1163    end Continue_Task;
1164
1165    ----------------
1166    -- Initialize --
1167    ----------------
1168
1169    procedure Initialize (Environment_Task : Task_Id) is
1170       act     : aliased struct_sigaction;
1171       old_act : aliased struct_sigaction;
1172       Tmp_Set : aliased sigset_t;
1173       Result  : Interfaces.C.int;
1174
1175       function State
1176         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1177       pragma Import (C, State, "__gnat_get_interrupt_state");
1178       --  Get interrupt state. Defined in a-init.c. The input argument is
1179       --  the interrupt number, and the result is one of the following:
1180
1181       Default : constant Character := 's';
1182       --    'n'   this interrupt not set by any Interrupt_State pragma
1183       --    'u'   Interrupt_State pragma set state to User
1184       --    'r'   Interrupt_State pragma set state to Runtime
1185       --    's'   Interrupt_State pragma set state to System (use "default"
1186       --           system handler)
1187
1188    begin
1189       Environment_Task_Id := Environment_Task;
1190
1191       Interrupt_Management.Initialize;
1192
1193       --  Initialize the lock used to synchronize chain of all ATCBs
1194
1195       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1196
1197       Specific.Initialize (Environment_Task);
1198
1199       --  Make environment task known here because it doesn't go through
1200       --  Activate_Tasks, which does it for all other tasks.
1201
1202       Known_Tasks (Known_Tasks'First) := Environment_Task;
1203       Environment_Task.Known_Tasks_Index := Known_Tasks'First;
1204
1205       Enter_Task (Environment_Task);
1206
1207       --  Install the abort-signal handler
1208
1209       if State (System.Interrupt_Management.Abort_Task_Interrupt)
1210                                                      /= Default
1211       then
1212          act.sa_flags := 0;
1213          act.sa_handler := Abort_Handler'Address;
1214
1215          Result := sigemptyset (Tmp_Set'Access);
1216          pragma Assert (Result = 0);
1217          act.sa_mask := Tmp_Set;
1218
1219          Result :=
1220            sigaction (
1221              Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1222              act'Unchecked_Access,
1223              old_act'Unchecked_Access);
1224          pragma Assert (Result = 0);
1225       end if;
1226    end Initialize;
1227
1228    --  NOTE: Unlike other pthread implementations, we do *not* mask all
1229    --  signals here since we handle signals using the process-wide primitive
1230    --  signal, rather than using sigthreadmask and sigwait. The reason of
1231    --  this difference is that sigwait doesn't work when some critical
1232    --  signals (SIGABRT, SIGPIPE) are masked.
1233
1234    -----------------------
1235    -- Set_Task_Affinity --
1236    -----------------------
1237
1238    procedure Set_Task_Affinity (T : ST.Task_Id) is
1239       pragma Unreferenced (T);
1240
1241    begin
1242       --  Setting task affinity is not supported by the underlying system
1243
1244       null;
1245    end Set_Task_Affinity;
1246
1247 end System.Task_Primitives.Operations;