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) 1992-2006, 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 2,  or (at your option) any later ver- --
  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.Task_Primitives.Interrupt_Operations;
  67 --  used for Get_Interrupt_ID
  68
  69 with System.Soft_Links;
  70 --  used for Defer/Undefer_Abort
  71
  72 --  We use System.Soft_Links instead of System.Tasking.Initialization
  73 --  because the later is a higher level package that we shouldn't depend on.
  74 --  For example when using the restricted run time, it is replaced by
  75 --  System.Tasking.Restricted.Stages.
  76
  77 with Unchecked_Conversion;
  78 with Unchecked_Deallocation;
  79
  80 package body System.Task_Primitives.Operations is
  81
  82    package SSL renames System.Soft_Links;
  83
  84    use System.Tasking.Debug;
  85    use System.Tasking;
  86    use Interfaces.C;
  87    use System.OS_Interface;
  88    use System.Parameters;
  89    use System.OS_Primitives;
  90
  91    package PIO renames System.Task_Primitives.Interrupt_Operations;
  92
  93    ----------------
  94    -- Local Data --
  95    ----------------
  96
  97    --  The followings are logically constants, but need to be initialized
  98    --  at run time.
  99
 100    Single_RTS_Lock : aliased RTS_Lock;
 101    --  This is a lock to allow only one thread of control in the RTS at
 102    --  a time; it is used to execute in mutual exclusion from all other tasks.
 103    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
 104
 105    ATCB_Key : aliased pthread_key_t;
 106    --  Key used to find the Ada Task_Id associated with a thread
 107
 108    Environment_Task_Id : Task_Id;
 109    --  A variable to hold Task_Id for the environment task
 110
 111    Unblocked_Signal_Mask : aliased sigset_t;
 112    --  The set of signals that should unblocked in all tasks
 113
 114    Time_Slice_Val : Integer;
 115    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 116
 117    Dispatching_Policy : Character;
 118    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 119
 120    --  Note: the reason that Locking_Policy is not needed is that this
 121    --  is not implemented for DCE threads. The HPUX 10 port is at this
 122    --  stage considered dead, and no further work is planned on it.
 123
 124    Foreign_Task_Elaborated : aliased Boolean := True;
 125    --  Used to identified fake tasks (i.e., non-Ada Threads)
 126
 127    --------------------
 128    -- Local Packages --
 129    --------------------
 130
 131    package Specific is
 132
 133       procedure Initialize (Environment_Task : Task_Id);
 134       pragma Inline (Initialize);
 135       --  Initialize various data needed by this package
 136
 137       function Is_Valid_Task return Boolean;
 138       pragma Inline (Is_Valid_Task);
 139       --  Does the executing thread have a TCB?
 140
 141       procedure Set (Self_Id : Task_Id);
 142       pragma Inline (Set);
 143       --  Set the self id for the current task
 144
 145       function Self return Task_Id;
 146       pragma Inline (Self);
 147       --  Return a pointer to the Ada Task Control Block of the calling task
 148
 149    end Specific;
 150
 151    package body Specific is separate;
 152    --  The body of this package is target specific
 153
 154    ---------------------------------
 155    -- Support for foreign threads --
 156    ---------------------------------
 157
 158    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 159    --  Allocate and Initialize a new ATCB for the current Thread
 160
 161    function Register_Foreign_Thread
 162      (Thread : Thread_Id) return Task_Id is separate;
 163
 164    -----------------------
 165    -- Local Subprograms --
 166    -----------------------
 167
 168    procedure Abort_Handler (Sig : Signal);
 169
 170    function To_Address is new Unchecked_Conversion (Task_Id, System.Address);
 171
 172    -------------------
 173    -- Abort_Handler --
 174    -------------------
 175
 176    procedure Abort_Handler (Sig : Signal) is
 177       pragma Unreferenced (Sig);
 178
 179       Self_Id : constant Task_Id := Self;
 180       Result  : Interfaces.C.int;
 181       Old_Set : aliased sigset_t;
 182
 183    begin
 184       if Self_Id.Deferral_Level = 0
 185         and then Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level and then
 186         not Self_Id.Aborting
 187       then
 188          Self_Id.Aborting := True;
 189
 190          --  Make sure signals used for RTS internal purpose are unmasked
 191
 192          Result := pthread_sigmask (SIG_UNBLOCK,
 193            Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
 194          pragma Assert (Result = 0);
 195
 196          raise Standard'Abort_Signal;
 197       end if;
 198    end Abort_Handler;
 199
 200    -----------------
 201    -- Stack_Guard --
 202    -----------------
 203
 204    --  The underlying thread system sets a guard page at the
 205    --  bottom of a thread stack, so nothing is needed.
 206    --  ??? Check the comment above
 207
 208    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 209       pragma Unreferenced (T, On);
 210    begin
 211       null;
 212    end Stack_Guard;
 213
 214    -------------------
 215    -- Get_Thread_Id --
 216    -------------------
 217
 218    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 219    begin
 220       return T.Common.LL.Thread;
 221    end Get_Thread_Id;
 222
 223    ----------
 224    -- Self --
 225    ----------
 226
 227    function Self return Task_Id renames Specific.Self;
 228
 229    ---------------------
 230    -- Initialize_Lock --
 231    ---------------------
 232
 233    --  Note: mutexes and cond_variables needed per-task basis are
 234    --        initialized in Initialize_TCB and the Storage_Error is
 235    --        handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
 236    --        used in RTS is initialized before any status change of RTS.
 237    --        Therefore rasing Storage_Error in the following routines
 238    --        should be able to be handled safely.
 239
 240    procedure Initialize_Lock
 241      (Prio : System.Any_Priority;
 242       L    : access Lock)
 243    is
 244       Attributes : aliased pthread_mutexattr_t;
 245       Result     : Interfaces.C.int;
 246
 247    begin
 248       Result := pthread_mutexattr_init (Attributes'Access);
 249       pragma Assert (Result = 0 or else Result = ENOMEM);
 250
 251       if Result = ENOMEM then
 252          raise Storage_Error;
 253       end if;
 254
 255       L.Priority := Prio;
 256
 257       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 258       pragma Assert (Result = 0 or else Result = ENOMEM);
 259
 260       if Result = ENOMEM then
 261          raise Storage_Error;
 262       end if;
 263
 264       Result := pthread_mutexattr_destroy (Attributes'Access);
 265       pragma Assert (Result = 0);
 266    end Initialize_Lock;
 267
 268    procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
 269       pragma Unreferenced (Level);
 270
 271       Attributes : aliased pthread_mutexattr_t;
 272       Result     : Interfaces.C.int;
 273
 274    begin
 275       Result := pthread_mutexattr_init (Attributes'Access);
 276       pragma Assert (Result = 0 or else Result = ENOMEM);
 277
 278       if Result = ENOMEM then
 279          raise Storage_Error;
 280       end if;
 281
 282       Result := pthread_mutex_init (L, Attributes'Access);
 283
 284       pragma Assert (Result = 0 or else Result = ENOMEM);
 285
 286       if Result = ENOMEM then
 287          raise Storage_Error;
 288       end if;
 289
 290       Result := pthread_mutexattr_destroy (Attributes'Access);
 291       pragma Assert (Result = 0);
 292    end Initialize_Lock;
 293
 294    -------------------
 295    -- Finalize_Lock --
 296    -------------------
 297
 298    procedure Finalize_Lock (L : access Lock) is
 299       Result : Interfaces.C.int;
 300    begin
 301       Result := pthread_mutex_destroy (L.L'Access);
 302       pragma Assert (Result = 0);
 303    end Finalize_Lock;
 304
 305    procedure Finalize_Lock (L : access RTS_Lock) is
 306       Result : Interfaces.C.int;
 307    begin
 308       Result := pthread_mutex_destroy (L);
 309       pragma Assert (Result = 0);
 310    end Finalize_Lock;
 311
 312    ----------------
 313    -- Write_Lock --
 314    ----------------
 315
 316    procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 317       Result : Interfaces.C.int;
 318
 319    begin
 320       L.Owner_Priority := Get_Priority (Self);
 321
 322       if L.Priority < L.Owner_Priority then
 323          Ceiling_Violation := True;
 324          return;
 325       end if;
 326
 327       Result := pthread_mutex_lock (L.L'Access);
 328       pragma Assert (Result = 0);
 329       Ceiling_Violation := False;
 330    end Write_Lock;
 331
 332    procedure Write_Lock
 333      (L : access RTS_Lock; Global_Lock : Boolean := False)
 334    is
 335       Result : Interfaces.C.int;
 336    begin
 337       if not Single_Lock or else Global_Lock then
 338          Result := pthread_mutex_lock (L);
 339          pragma Assert (Result = 0);
 340       end if;
 341    end Write_Lock;
 342
 343    procedure Write_Lock (T : Task_Id) is
 344       Result : Interfaces.C.int;
 345    begin
 346       if not Single_Lock then
 347          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 348          pragma Assert (Result = 0);
 349       end if;
 350    end Write_Lock;
 351
 352    ---------------
 353    -- Read_Lock --
 354    ---------------
 355
 356    procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 357    begin
 358       Write_Lock (L, Ceiling_Violation);
 359    end Read_Lock;
 360
 361    ------------
 362    -- Unlock --
 363    ------------
 364
 365    procedure Unlock (L : 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 (L : access RTS_Lock; Global_Lock : Boolean := False) is
 373       Result : Interfaces.C.int;
 374    begin
 375       if not Single_Lock or else Global_Lock then
 376          Result := pthread_mutex_unlock (L);
 377          pragma Assert (Result = 0);
 378       end if;
 379    end Unlock;
 380
 381    procedure Unlock (T : Task_Id) is
 382       Result : Interfaces.C.int;
 383    begin
 384       if not Single_Lock then
 385          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 386          pragma Assert (Result = 0);
 387       end if;
 388    end Unlock;
 389
 390    -----------
 391    -- Sleep --
 392    -----------
 393
 394    procedure Sleep
 395      (Self_ID : Task_Id;
 396       Reason  : System.Tasking.Task_States)
 397    is
 398       pragma Unreferenced (Reason);
 399
 400       Result : Interfaces.C.int;
 401    begin
 402       if Single_Lock then
 403          Result := pthread_cond_wait
 404            (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 405       else
 406          Result := pthread_cond_wait
 407            (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 408       end if;
 409
 410       --  EINTR is not considered a failure
 411
 412       pragma Assert (Result = 0 or else Result = EINTR);
 413    end Sleep;
 414
 415    -----------------
 416    -- Timed_Sleep --
 417    -----------------
 418
 419    procedure Timed_Sleep
 420      (Self_ID  : Task_Id;
 421       Time     : Duration;
 422       Mode     : ST.Delay_Modes;
 423       Reason   : System.Tasking.Task_States;
 424       Timedout : out Boolean;
 425       Yielded  : out Boolean)
 426    is
 427       pragma Unreferenced (Reason);
 428
 429       Check_Time : constant Duration := Monotonic_Clock;
 430       Abs_Time   : Duration;
 431       Request    : aliased timespec;
 432       Result     : Interfaces.C.int;
 433
 434    begin
 435       Timedout := True;
 436       Yielded := False;
 437
 438       if Mode = Relative then
 439          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 440       else
 441          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 442       end if;
 443
 444       if Abs_Time > Check_Time then
 445          Request := To_Timespec (Abs_Time);
 446
 447          loop
 448             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 449               or else Self_ID.Pending_Priority_Change;
 450
 451             if Single_Lock then
 452                Result := pthread_cond_timedwait
 453                  (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
 454                   Request'Access);
 455
 456             else
 457                Result := pthread_cond_timedwait
 458                  (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
 459                   Request'Access);
 460             end if;
 461
 462             exit when Abs_Time <= Monotonic_Clock;
 463
 464             if Result = 0 or Result = EINTR then
 465
 466                --  Somebody may have called Wakeup for us
 467
 468                Timedout := False;
 469                exit;
 470             end if;
 471
 472             pragma Assert (Result = ETIMEDOUT);
 473          end loop;
 474       end if;
 475    end Timed_Sleep;
 476
 477    -----------------
 478    -- Timed_Delay --
 479    -----------------
 480
 481    procedure Timed_Delay
 482      (Self_ID : Task_Id;
 483       Time    : Duration;
 484       Mode    : ST.Delay_Modes)
 485    is
 486       Check_Time : constant Duration := Monotonic_Clock;
 487       Abs_Time   : Duration;
 488       Request    : aliased timespec;
 489
 490       Result : Interfaces.C.int;
 491       pragma Warnings (Off, Result);
 492
 493    begin
 494       if Single_Lock then
 495          Lock_RTS;
 496       end if;
 497
 498       Write_Lock (Self_ID);
 499
 500       if Mode = Relative then
 501          Abs_Time := Time + Check_Time;
 502       else
 503          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 504       end if;
 505
 506       if Abs_Time > Check_Time then
 507          Request := To_Timespec (Abs_Time);
 508          Self_ID.Common.State := Delay_Sleep;
 509
 510          loop
 511             if Self_ID.Pending_Priority_Change then
 512                Self_ID.Pending_Priority_Change := False;
 513                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 514                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 515             end if;
 516
 517             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 518
 519             if Single_Lock then
 520                Result := pthread_cond_timedwait
 521                            (Self_ID.Common.LL.CV'Access,
 522                             Single_RTS_Lock'Access,
 523                             Request'Access);
 524             else
 525                Result := pthread_cond_timedwait
 526                           (Self_ID.Common.LL.CV'Access,
 527                            Self_ID.Common.LL.L'Access,
 528                            Request'Access);
 529             end if;
 530
 531             exit when Abs_Time <= Monotonic_Clock;
 532
 533             pragma Assert (Result = 0 or else
 534               Result = ETIMEDOUT or else
 535               Result = EINTR);
 536          end loop;
 537
 538          Self_ID.Common.State := Runnable;
 539       end if;
 540
 541       Unlock (Self_ID);
 542
 543       if Single_Lock then
 544          Unlock_RTS;
 545       end if;
 546
 547       Result := sched_yield;
 548    end Timed_Delay;
 549
 550    ---------------------
 551    -- Monotonic_Clock --
 552    ---------------------
 553
 554    function Monotonic_Clock return Duration is
 555       TS     : aliased timespec;
 556       Result : Interfaces.C.int;
 557    begin
 558       Result := Clock_Gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 559       pragma Assert (Result = 0);
 560       return To_Duration (TS);
 561    end Monotonic_Clock;
 562
 563    -------------------
 564    -- RT_Resolution --
 565    -------------------
 566
 567    function RT_Resolution return Duration is
 568    begin
 569       return 10#1.0#E-6;
 570    end RT_Resolution;
 571
 572    ------------
 573    -- Wakeup --
 574    ------------
 575
 576    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 577       pragma Unreferenced (Reason);
 578
 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       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: we assume that we are on a single processor with run-til-blocked
 611    --  scheduling.
 612
 613    procedure Set_Priority
 614      (T                   : Task_Id;
 615       Prio                : System.Any_Priority;
 616       Loss_Of_Inheritance : Boolean := False)
 617    is
 618       Result     : Interfaces.C.int;
 619       Array_Item : Integer;
 620       Param      : aliased struct_sched_param;
 621
 622       function Get_Policy (Prio : System.Any_Priority) return Character;
 623       pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 624       --  Get priority specific dispatching policy
 625
 626       Priority_Specific_Policy : constant Character := Get_Policy (Prio);
 627       --  Upper case first character of the policy name corresponding to the
 628       --  task as set by a Priority_Specific_Dispatching pragma.
 629
 630    begin
 631       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 632
 633       if Dispatching_Policy = 'R'
 634         or else Priority_Specific_Policy = 'R'
 635         or else Time_Slice_Val > 0
 636       then
 637          Result := 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 := pthread_setschedparam
 645            (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 646
 647       else
 648          Result := pthread_setschedparam
 649            (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 650       end if;
 651
 652       pragma Assert (Result = 0);
 653
 654       if Dispatching_Policy = 'F' or else Priority_Specific_Policy = 'F' then
 655
 656          --  Annex D requirement [RM D.2.2 par. 9]:
 657          --    If the task drops its priority due to the loss of inherited
 658          --    priority, it is added at the head of the ready queue for its
 659          --    new active priority.
 660
 661          if Loss_Of_Inheritance
 662            and then Prio < T.Common.Current_Priority
 663          then
 664             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 665             Prio_Array (T.Common.Base_Priority) := Array_Item;
 666
 667             loop
 668                --  Let some processes a chance to arrive
 669
 670                Yield;
 671
 672                --  Then wait for our turn to proceed
 673
 674                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 675                  or else Prio_Array (T.Common.Base_Priority) = 1;
 676             end loop;
 677
 678             Prio_Array (T.Common.Base_Priority) :=
 679               Prio_Array (T.Common.Base_Priority) - 1;
 680          end if;
 681       end if;
 682
 683       T.Common.Current_Priority := Prio;
 684    end Set_Priority;
 685
 686    ------------------
 687    -- Get_Priority --
 688    ------------------
 689
 690    function Get_Priority (T : Task_Id) return System.Any_Priority is
 691    begin
 692       return T.Common.Current_Priority;
 693    end Get_Priority;
 694
 695    ----------------
 696    -- Enter_Task --
 697    ----------------
 698
 699    procedure Enter_Task (Self_ID : Task_Id) is
 700    begin
 701       Self_ID.Common.LL.Thread := pthread_self;
 702       Specific.Set (Self_ID);
 703
 704       Lock_RTS;
 705
 706       for J in Known_Tasks'Range loop
 707          if Known_Tasks (J) = null then
 708             Known_Tasks (J) := Self_ID;
 709             Self_ID.Known_Tasks_Index := J;
 710             exit;
 711          end if;
 712       end loop;
 713
 714       Unlock_RTS;
 715    end Enter_Task;
 716
 717    --------------
 718    -- New_ATCB --
 719    --------------
 720
 721    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 722    begin
 723       return new Ada_Task_Control_Block (Entry_Num);
 724    end New_ATCB;
 725
 726    -------------------
 727    -- Is_Valid_Task --
 728    -------------------
 729
 730    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 731
 732    -----------------------------
 733    -- Register_Foreign_Thread --
 734    -----------------------------
 735
 736    function Register_Foreign_Thread return Task_Id is
 737    begin
 738       if Is_Valid_Task then
 739          return Self;
 740       else
 741          return Register_Foreign_Thread (pthread_self);
 742       end if;
 743    end Register_Foreign_Thread;
 744
 745    --------------------
 746    -- Initialize_TCB --
 747    --------------------
 748
 749    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 750       Mutex_Attr : aliased pthread_mutexattr_t;
 751       Result     : Interfaces.C.int;
 752       Cond_Attr  : aliased pthread_condattr_t;
 753
 754    begin
 755       if not Single_Lock then
 756          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 757          pragma Assert (Result = 0 or else Result = ENOMEM);
 758
 759          if Result = 0 then
 760             Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 761               Mutex_Attr'Access);
 762             pragma Assert (Result = 0 or else Result = ENOMEM);
 763          end if;
 764
 765          if Result /= 0 then
 766             Succeeded := False;
 767             return;
 768          end if;
 769
 770          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 771          pragma Assert (Result = 0);
 772       end if;
 773
 774       Result := pthread_condattr_init (Cond_Attr'Access);
 775       pragma Assert (Result = 0 or else Result = ENOMEM);
 776
 777       if Result = 0 then
 778          Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 779            Cond_Attr'Access);
 780          pragma Assert (Result = 0 or else Result = ENOMEM);
 781       end if;
 782
 783       if Result = 0 then
 784          Succeeded := True;
 785       else
 786          if not Single_Lock then
 787             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 788             pragma Assert (Result = 0);
 789          end if;
 790
 791          Succeeded := False;
 792       end if;
 793
 794       Result := pthread_condattr_destroy (Cond_Attr'Access);
 795       pragma Assert (Result = 0);
 796    end Initialize_TCB;
 797
 798    -----------------
 799    -- Create_Task --
 800    -----------------
 801
 802    procedure Create_Task
 803      (T          : Task_Id;
 804       Wrapper    : System.Address;
 805       Stack_Size : System.Parameters.Size_Type;
 806       Priority   : System.Any_Priority;
 807       Succeeded  : out Boolean)
 808    is
 809       Attributes : aliased pthread_attr_t;
 810       Result     : Interfaces.C.int;
 811
 812       function Thread_Body_Access is new
 813         Unchecked_Conversion (System.Address, Thread_Body);
 814
 815    begin
 816       Result := pthread_attr_init (Attributes'Access);
 817       pragma Assert (Result = 0 or else Result = ENOMEM);
 818
 819       if Result /= 0 then
 820          Succeeded := False;
 821          return;
 822       end if;
 823
 824       Result := pthread_attr_setstacksize
 825         (Attributes'Access, Interfaces.C.size_t (Stack_Size));
 826       pragma Assert (Result = 0);
 827
 828       --  Since the initial signal mask of a thread is inherited from the
 829       --  creator, and the Environment task has all its signals masked, we
 830       --  do not need to manipulate caller's signal mask at this point.
 831       --  All tasks in RTS will have All_Tasks_Mask initially.
 832
 833       Result := pthread_create
 834         (T.Common.LL.Thread'Access,
 835          Attributes'Access,
 836          Thread_Body_Access (Wrapper),
 837          To_Address (T));
 838       pragma Assert (Result = 0 or else Result = EAGAIN);
 839
 840       Succeeded := Result = 0;
 841
 842       pthread_detach (T.Common.LL.Thread'Access);
 843       --  Detach the thread using pthread_detach, sinc DCE threads do not have
 844       --  pthread_attr_set_detachstate.
 845
 846       Result := pthread_attr_destroy (Attributes'Access);
 847       pragma Assert (Result = 0);
 848
 849       Set_Priority (T, Priority);
 850    end Create_Task;
 851
 852    ------------------
 853    -- Finalize_TCB --
 854    ------------------
 855
 856    procedure Finalize_TCB (T : Task_Id) is
 857       Result  : Interfaces.C.int;
 858       Tmp     : Task_Id := T;
 859       Is_Self : constant Boolean := T = Self;
 860
 861       procedure Free is new
 862         Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 863
 864    begin
 865       if not Single_Lock then
 866          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 867          pragma Assert (Result = 0);
 868       end if;
 869
 870       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 871       pragma Assert (Result = 0);
 872
 873       if T.Known_Tasks_Index /= -1 then
 874          Known_Tasks (T.Known_Tasks_Index) := null;
 875       end if;
 876
 877       Free (Tmp);
 878
 879       if Is_Self then
 880          Specific.Set (null);
 881       end if;
 882    end Finalize_TCB;
 883
 884    ---------------
 885    -- Exit_Task --
 886    ---------------
 887
 888    procedure Exit_Task is
 889    begin
 890       Specific.Set (null);
 891    end Exit_Task;
 892
 893    ----------------
 894    -- Abort_Task --
 895    ----------------
 896
 897    procedure Abort_Task (T : Task_Id) is
 898    begin
 899       --
 900       --  Interrupt Server_Tasks may be waiting on an "event" flag (signal)
 901       --
 902       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 903          System.Interrupt_Management.Operations.Interrupt_Self_Process
 904            (System.Interrupt_Management.Interrupt_ID
 905              (PIO.Get_Interrupt_ID (T)));
 906       end if;
 907    end Abort_Task;
 908
 909    ----------------
 910    -- Initialize --
 911    ----------------
 912
 913    procedure Initialize (S : in out Suspension_Object) is
 914       Mutex_Attr : aliased pthread_mutexattr_t;
 915       Cond_Attr  : aliased pthread_condattr_t;
 916       Result     : Interfaces.C.int;
 917    begin
 918       --  Initialize internal state. It is always initialized to False (ARM
 919       --  D.10 par. 6).
 920
 921       S.State := False;
 922       S.Waiting := False;
 923
 924       --  Initialize internal mutex
 925
 926       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 927       pragma Assert (Result = 0 or else Result = ENOMEM);
 928
 929       if Result = ENOMEM then
 930          raise Storage_Error;
 931       end if;
 932
 933       --  Initialize internal condition variable
 934
 935       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 936       pragma Assert (Result = 0 or else Result = ENOMEM);
 937
 938       if Result /= 0 then
 939          Result := pthread_mutex_destroy (S.L'Access);
 940          pragma Assert (Result = 0);
 941
 942          if Result = ENOMEM then
 943             raise Storage_Error;
 944          end if;
 945       end if;
 946    end Initialize;
 947
 948    --------------
 949    -- Finalize --
 950    --------------
 951
 952    procedure Finalize (S : in out Suspension_Object) is
 953       Result  : Interfaces.C.int;
 954    begin
 955       --  Destroy internal mutex
 956
 957       Result := pthread_mutex_destroy (S.L'Access);
 958       pragma Assert (Result = 0);
 959
 960       --  Destroy internal condition variable
 961
 962       Result := pthread_cond_destroy (S.CV'Access);
 963       pragma Assert (Result = 0);
 964    end Finalize;
 965
 966    -------------------
 967    -- Current_State --
 968    -------------------
 969
 970    function Current_State (S : Suspension_Object) return Boolean is
 971    begin
 972       --  We do not want to use lock on this read operation. State is marked
 973       --  as Atomic so that we ensure that the value retrieved is correct.
 974
 975       return S.State;
 976    end Current_State;
 977
 978    ---------------
 979    -- Set_False --
 980    ---------------
 981
 982    procedure Set_False (S : in out Suspension_Object) is
 983       Result  : Interfaces.C.int;
 984    begin
 985       SSL.Abort_Defer.all;
 986
 987       Result := pthread_mutex_lock (S.L'Access);
 988       pragma Assert (Result = 0);
 989
 990       S.State := False;
 991
 992       Result := pthread_mutex_unlock (S.L'Access);
 993       pragma Assert (Result = 0);
 994
 995       SSL.Abort_Undefer.all;
 996    end Set_False;
 997
 998    --------------
 999    -- Set_True --
1000    --------------
1001
1002    procedure Set_True (S : in out Suspension_Object) is
1003       Result : Interfaces.C.int;
1004    begin
1005       SSL.Abort_Defer.all;
1006
1007       Result := pthread_mutex_lock (S.L'Access);
1008       pragma Assert (Result = 0);
1009
1010       --  If there is already a task waiting on this suspension object then
1011       --  we resume it, leaving the state of the suspension object to False,
1012       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1013       --  the state to True.
1014
1015       if S.Waiting then
1016          S.Waiting := False;
1017          S.State := False;
1018
1019          Result := pthread_cond_signal (S.CV'Access);
1020          pragma Assert (Result = 0);
1021       else
1022          S.State := True;
1023       end if;
1024
1025       Result := pthread_mutex_unlock (S.L'Access);
1026       pragma Assert (Result = 0);
1027
1028       SSL.Abort_Undefer.all;
1029    end Set_True;
1030
1031    ------------------------
1032    -- Suspend_Until_True --
1033    ------------------------
1034
1035    procedure Suspend_Until_True (S : in out Suspension_Object) is
1036       Result : Interfaces.C.int;
1037    begin
1038       SSL.Abort_Defer.all;
1039
1040       Result := pthread_mutex_lock (S.L'Access);
1041       pragma Assert (Result = 0);
1042
1043       if S.Waiting then
1044          --  Program_Error must be raised upon calling Suspend_Until_True
1045          --  if another task is already waiting on that suspension object
1046          --  (ARM D.10 par. 10).
1047
1048          Result := pthread_mutex_unlock (S.L'Access);
1049          pragma Assert (Result = 0);
1050
1051          SSL.Abort_Undefer.all;
1052
1053          raise Program_Error;
1054       else
1055          --  Suspend the task if the state is False. Otherwise, the task
1056          --  continues its execution, and the state of the suspension object
1057          --  is set to False (ARM D.10 par. 9).
1058
1059          if S.State then
1060             S.State := False;
1061          else
1062             S.Waiting := True;
1063             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1064          end if;
1065
1066          Result := pthread_mutex_unlock (S.L'Access);
1067          pragma Assert (Result = 0);
1068
1069          SSL.Abort_Undefer.all;
1070       end if;
1071    end Suspend_Until_True;
1072
1073    ----------------
1074    -- Check_Exit --
1075    ----------------
1076
1077    --  Dummy version
1078
1079    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1080       pragma Unreferenced (Self_ID);
1081    begin
1082       return True;
1083    end Check_Exit;
1084
1085    --------------------
1086    -- Check_No_Locks --
1087    --------------------
1088
1089    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1090       pragma Unreferenced (Self_ID);
1091    begin
1092       return True;
1093    end Check_No_Locks;
1094
1095    ----------------------
1096    -- Environment_Task --
1097    ----------------------
1098
1099    function Environment_Task return Task_Id is
1100    begin
1101       return Environment_Task_Id;
1102    end Environment_Task;
1103
1104    --------------
1105    -- Lock_RTS --
1106    --------------
1107
1108    procedure Lock_RTS is
1109    begin
1110       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1111    end Lock_RTS;
1112
1113    ----------------
1114    -- Unlock_RTS --
1115    ----------------
1116
1117    procedure Unlock_RTS is
1118    begin
1119       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1120    end Unlock_RTS;
1121
1122    ------------------
1123    -- Suspend_Task --
1124    ------------------
1125
1126    function Suspend_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 Suspend_Task;
1135
1136    -----------------
1137    -- Resume_Task --
1138    -----------------
1139
1140    function Resume_Task
1141      (T           : ST.Task_Id;
1142       Thread_Self : Thread_Id) return Boolean
1143    is
1144       pragma Unreferenced (T);
1145       pragma Unreferenced (Thread_Self);
1146    begin
1147       return False;
1148    end Resume_Task;
1149
1150    ----------------
1151    -- Initialize --
1152    ----------------
1153
1154    procedure Initialize (Environment_Task : Task_Id) is
1155       act       : aliased struct_sigaction;
1156       old_act   : aliased struct_sigaction;
1157       Tmp_Set   : aliased sigset_t;
1158       Result    : Interfaces.C.int;
1159
1160       function State
1161         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1162       pragma Import (C, State, "__gnat_get_interrupt_state");
1163       --  Get interrupt state. Defined in a-init.c. The input argument is
1164       --  the interrupt number, and the result is one of the following:
1165
1166       Default : constant Character := 's';
1167       --    'n'   this interrupt not set by any Interrupt_State pragma
1168       --    'u'   Interrupt_State pragma set state to User
1169       --    'r'   Interrupt_State pragma set state to Runtime
1170       --    's'   Interrupt_State pragma set state to System (use "default"
1171       --           system handler)
1172
1173    begin
1174       Environment_Task_Id := Environment_Task;
1175
1176       Interrupt_Management.Initialize;
1177
1178       --  Initialize the lock used to synchronize chain of all ATCBs
1179
1180       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1181
1182       Specific.Initialize (Environment_Task);
1183
1184       Enter_Task (Environment_Task);
1185
1186       --  Install the abort-signal handler
1187
1188       if State (System.Interrupt_Management.Abort_Task_Interrupt)
1189                                                      /= Default
1190       then
1191          act.sa_flags := 0;
1192          act.sa_handler := Abort_Handler'Address;
1193
1194          Result := sigemptyset (Tmp_Set'Access);
1195          pragma Assert (Result = 0);
1196          act.sa_mask := Tmp_Set;
1197
1198          Result :=
1199            sigaction (
1200              Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1201              act'Unchecked_Access,
1202              old_act'Unchecked_Access);
1203          pragma Assert (Result = 0);
1204       end if;
1205    end Initialize;
1206
1207    --  NOTE: Unlike other pthread implementations, we do *not* mask all
1208    --  signals here since we handle signals using the process-wide primitive
1209    --  signal, rather than using sigthreadmask and sigwait. The reason of
1210    --  this difference is that sigwait doesn't work when some critical
1211    --  signals (SIGABRT, SIGPIPE) are masked.
1212
1213 end System.Task_Primitives.Operations;