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       Result     : Interfaces.C.int;
 490
 491    begin
 492       if Single_Lock then
 493          Lock_RTS;
 494       end if;
 495
 496       Write_Lock (Self_ID);
 497
 498       if Mode = Relative then
 499          Abs_Time := Time + Check_Time;
 500       else
 501          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 502       end if;
 503
 504       if Abs_Time > Check_Time then
 505          Request := To_Timespec (Abs_Time);
 506          Self_ID.Common.State := Delay_Sleep;
 507
 508          loop
 509             if Self_ID.Pending_Priority_Change then
 510                Self_ID.Pending_Priority_Change := False;
 511                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 512                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 513             end if;
 514
 515             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 516
 517             if Single_Lock then
 518                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 519                  Single_RTS_Lock'Access, Request'Access);
 520             else
 521                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 522                  Self_ID.Common.LL.L'Access, Request'Access);
 523             end if;
 524
 525             exit when Abs_Time <= Monotonic_Clock;
 526
 527             pragma Assert (Result = 0 or else
 528               Result = ETIMEDOUT or else
 529               Result = EINTR);
 530          end loop;
 531
 532          Self_ID.Common.State := Runnable;
 533       end if;
 534
 535       Unlock (Self_ID);
 536
 537       if Single_Lock then
 538          Unlock_RTS;
 539       end if;
 540
 541       Result := sched_yield;
 542    end Timed_Delay;
 543
 544    ---------------------
 545    -- Monotonic_Clock --
 546    ---------------------
 547
 548    function Monotonic_Clock return Duration is
 549       TS     : aliased timespec;
 550       Result : Interfaces.C.int;
 551    begin
 552       Result := Clock_Gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 553       pragma Assert (Result = 0);
 554       return To_Duration (TS);
 555    end Monotonic_Clock;
 556
 557    -------------------
 558    -- RT_Resolution --
 559    -------------------
 560
 561    function RT_Resolution return Duration is
 562    begin
 563       return 10#1.0#E-6;
 564    end RT_Resolution;
 565
 566    ------------
 567    -- Wakeup --
 568    ------------
 569
 570    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 571       pragma Unreferenced (Reason);
 572
 573       Result : Interfaces.C.int;
 574
 575    begin
 576       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 577       pragma Assert (Result = 0);
 578    end Wakeup;
 579
 580    -----------
 581    -- Yield --
 582    -----------
 583
 584    procedure Yield (Do_Yield : Boolean := True) is
 585       Result : Interfaces.C.int;
 586       pragma Unreferenced (Result);
 587    begin
 588       if Do_Yield then
 589          Result := sched_yield;
 590       end if;
 591    end Yield;
 592
 593    ------------------
 594    -- Set_Priority --
 595    ------------------
 596
 597    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 598    pragma Atomic_Components (Prio_Array_Type);
 599
 600    Prio_Array : Prio_Array_Type;
 601    --  Global array containing the id of the currently running task for
 602    --  each priority.
 603    --
 604    --  Note: we assume that we are on a single processor with run-til-blocked
 605    --  scheduling.
 606
 607    procedure Set_Priority
 608      (T                   : Task_Id;
 609       Prio                : System.Any_Priority;
 610       Loss_Of_Inheritance : Boolean := False)
 611    is
 612       Result     : Interfaces.C.int;
 613       Array_Item : Integer;
 614       Param      : aliased struct_sched_param;
 615
 616    begin
 617       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 618
 619       if Time_Slice_Val > 0 then
 620          Result := pthread_setschedparam
 621            (T.Common.LL.Thread, SCHED_RR, Param'Access);
 622
 623       elsif Dispatching_Policy = 'F' or else Time_Slice_Val = 0 then
 624          Result := pthread_setschedparam
 625            (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 626
 627       else
 628          Result := pthread_setschedparam
 629            (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 630       end if;
 631
 632       pragma Assert (Result = 0);
 633
 634       if Dispatching_Policy = 'F' then
 635
 636          --  Annex D requirement [RM D.2.2 par. 9]:
 637          --    If the task drops its priority due to the loss of inherited
 638          --    priority, it is added at the head of the ready queue for its
 639          --    new active priority.
 640
 641          if Loss_Of_Inheritance
 642            and then Prio < T.Common.Current_Priority
 643          then
 644             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 645             Prio_Array (T.Common.Base_Priority) := Array_Item;
 646
 647             loop
 648                --  Let some processes a chance to arrive
 649
 650                Yield;
 651
 652                --  Then wait for our turn to proceed
 653
 654                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 655                  or else Prio_Array (T.Common.Base_Priority) = 1;
 656             end loop;
 657
 658             Prio_Array (T.Common.Base_Priority) :=
 659               Prio_Array (T.Common.Base_Priority) - 1;
 660          end if;
 661       end if;
 662
 663       T.Common.Current_Priority := Prio;
 664    end Set_Priority;
 665
 666    ------------------
 667    -- Get_Priority --
 668    ------------------
 669
 670    function Get_Priority (T : Task_Id) return System.Any_Priority is
 671    begin
 672       return T.Common.Current_Priority;
 673    end Get_Priority;
 674
 675    ----------------
 676    -- Enter_Task --
 677    ----------------
 678
 679    procedure Enter_Task (Self_ID : Task_Id) is
 680    begin
 681       Self_ID.Common.LL.Thread := pthread_self;
 682       Specific.Set (Self_ID);
 683
 684       Lock_RTS;
 685
 686       for J in Known_Tasks'Range loop
 687          if Known_Tasks (J) = null then
 688             Known_Tasks (J) := Self_ID;
 689             Self_ID.Known_Tasks_Index := J;
 690             exit;
 691          end if;
 692       end loop;
 693
 694       Unlock_RTS;
 695    end Enter_Task;
 696
 697    --------------
 698    -- New_ATCB --
 699    --------------
 700
 701    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 702    begin
 703       return new Ada_Task_Control_Block (Entry_Num);
 704    end New_ATCB;
 705
 706    -------------------
 707    -- Is_Valid_Task --
 708    -------------------
 709
 710    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 711
 712    -----------------------------
 713    -- Register_Foreign_Thread --
 714    -----------------------------
 715
 716    function Register_Foreign_Thread return Task_Id is
 717    begin
 718       if Is_Valid_Task then
 719          return Self;
 720       else
 721          return Register_Foreign_Thread (pthread_self);
 722       end if;
 723    end Register_Foreign_Thread;
 724
 725    --------------------
 726    -- Initialize_TCB --
 727    --------------------
 728
 729    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 730       Mutex_Attr : aliased pthread_mutexattr_t;
 731       Result     : Interfaces.C.int;
 732       Cond_Attr  : aliased pthread_condattr_t;
 733
 734    begin
 735       if not Single_Lock then
 736          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 737          pragma Assert (Result = 0 or else Result = ENOMEM);
 738
 739          if Result = 0 then
 740             Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 741               Mutex_Attr'Access);
 742             pragma Assert (Result = 0 or else Result = ENOMEM);
 743          end if;
 744
 745          if Result /= 0 then
 746             Succeeded := False;
 747             return;
 748          end if;
 749
 750          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 751          pragma Assert (Result = 0);
 752       end if;
 753
 754       Result := pthread_condattr_init (Cond_Attr'Access);
 755       pragma Assert (Result = 0 or else Result = ENOMEM);
 756
 757       if Result = 0 then
 758          Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 759            Cond_Attr'Access);
 760          pragma Assert (Result = 0 or else Result = ENOMEM);
 761       end if;
 762
 763       if Result = 0 then
 764          Succeeded := True;
 765       else
 766          if not Single_Lock then
 767             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 768             pragma Assert (Result = 0);
 769          end if;
 770
 771          Succeeded := False;
 772       end if;
 773
 774       Result := pthread_condattr_destroy (Cond_Attr'Access);
 775       pragma Assert (Result = 0);
 776    end Initialize_TCB;
 777
 778    -----------------
 779    -- Create_Task --
 780    -----------------
 781
 782    procedure Create_Task
 783      (T          : Task_Id;
 784       Wrapper    : System.Address;
 785       Stack_Size : System.Parameters.Size_Type;
 786       Priority   : System.Any_Priority;
 787       Succeeded  : out Boolean)
 788    is
 789       Attributes : aliased pthread_attr_t;
 790       Result     : Interfaces.C.int;
 791
 792       function Thread_Body_Access is new
 793         Unchecked_Conversion (System.Address, Thread_Body);
 794
 795    begin
 796       Result := pthread_attr_init (Attributes'Access);
 797       pragma Assert (Result = 0 or else Result = ENOMEM);
 798
 799       if Result /= 0 then
 800          Succeeded := False;
 801          return;
 802       end if;
 803
 804       Result := pthread_attr_setstacksize
 805         (Attributes'Access, Interfaces.C.size_t (Stack_Size));
 806       pragma Assert (Result = 0);
 807
 808       --  Since the initial signal mask of a thread is inherited from the
 809       --  creator, and the Environment task has all its signals masked, we
 810       --  do not need to manipulate caller's signal mask at this point.
 811       --  All tasks in RTS will have All_Tasks_Mask initially.
 812
 813       Result := pthread_create
 814         (T.Common.LL.Thread'Access,
 815          Attributes'Access,
 816          Thread_Body_Access (Wrapper),
 817          To_Address (T));
 818       pragma Assert (Result = 0 or else Result = EAGAIN);
 819
 820       Succeeded := Result = 0;
 821
 822       pthread_detach (T.Common.LL.Thread'Access);
 823       --  Detach the thread using pthread_detach, sinc DCE threads do not have
 824       --  pthread_attr_set_detachstate.
 825
 826       Result := pthread_attr_destroy (Attributes'Access);
 827       pragma Assert (Result = 0);
 828
 829       Set_Priority (T, Priority);
 830    end Create_Task;
 831
 832    ------------------
 833    -- Finalize_TCB --
 834    ------------------
 835
 836    procedure Finalize_TCB (T : Task_Id) is
 837       Result  : Interfaces.C.int;
 838       Tmp     : Task_Id := T;
 839       Is_Self : constant Boolean := T = Self;
 840
 841       procedure Free is new
 842         Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 843
 844    begin
 845       if not Single_Lock then
 846          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 847          pragma Assert (Result = 0);
 848       end if;
 849
 850       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 851       pragma Assert (Result = 0);
 852
 853       if T.Known_Tasks_Index /= -1 then
 854          Known_Tasks (T.Known_Tasks_Index) := null;
 855       end if;
 856
 857       Free (Tmp);
 858
 859       if Is_Self then
 860          Specific.Set (null);
 861       end if;
 862    end Finalize_TCB;
 863
 864    ---------------
 865    -- Exit_Task --
 866    ---------------
 867
 868    procedure Exit_Task is
 869    begin
 870       Specific.Set (null);
 871    end Exit_Task;
 872
 873    ----------------
 874    -- Abort_Task --
 875    ----------------
 876
 877    procedure Abort_Task (T : Task_Id) is
 878    begin
 879       --
 880       --  Interrupt Server_Tasks may be waiting on an "event" flag (signal)
 881       --
 882       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 883          System.Interrupt_Management.Operations.Interrupt_Self_Process
 884            (System.Interrupt_Management.Interrupt_ID
 885              (PIO.Get_Interrupt_ID (T)));
 886       end if;
 887    end Abort_Task;
 888
 889    ----------------
 890    -- Initialize --
 891    ----------------
 892
 893    procedure Initialize (S : in out Suspension_Object) is
 894       Mutex_Attr : aliased pthread_mutexattr_t;
 895       Cond_Attr  : aliased pthread_condattr_t;
 896       Result     : Interfaces.C.int;
 897    begin
 898       --  Initialize internal state. It is always initialized to False (ARM
 899       --  D.10 par. 6).
 900
 901       S.State := False;
 902       S.Waiting := False;
 903
 904       --  Initialize internal mutex
 905
 906       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 907       pragma Assert (Result = 0 or else Result = ENOMEM);
 908
 909       if Result = ENOMEM then
 910          raise Storage_Error;
 911       end if;
 912
 913       --  Initialize internal condition variable
 914
 915       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 916       pragma Assert (Result = 0 or else Result = ENOMEM);
 917
 918       if Result /= 0 then
 919          Result := pthread_mutex_destroy (S.L'Access);
 920          pragma Assert (Result = 0);
 921
 922          if Result = ENOMEM then
 923             raise Storage_Error;
 924          end if;
 925       end if;
 926    end Initialize;
 927
 928    --------------
 929    -- Finalize --
 930    --------------
 931
 932    procedure Finalize (S : in out Suspension_Object) is
 933       Result  : Interfaces.C.int;
 934    begin
 935       --  Destroy internal mutex
 936
 937       Result := pthread_mutex_destroy (S.L'Access);
 938       pragma Assert (Result = 0);
 939
 940       --  Destroy internal condition variable
 941
 942       Result := pthread_cond_destroy (S.CV'Access);
 943       pragma Assert (Result = 0);
 944    end Finalize;
 945
 946    -------------------
 947    -- Current_State --
 948    -------------------
 949
 950    function Current_State (S : Suspension_Object) return Boolean is
 951    begin
 952       --  We do not want to use lock on this read operation. State is marked
 953       --  as Atomic so that we ensure that the value retrieved is correct.
 954
 955       return S.State;
 956    end Current_State;
 957
 958    ---------------
 959    -- Set_False --
 960    ---------------
 961
 962    procedure Set_False (S : in out Suspension_Object) is
 963       Result  : Interfaces.C.int;
 964    begin
 965       SSL.Abort_Defer.all;
 966
 967       Result := pthread_mutex_lock (S.L'Access);
 968       pragma Assert (Result = 0);
 969
 970       S.State := False;
 971
 972       Result := pthread_mutex_unlock (S.L'Access);
 973       pragma Assert (Result = 0);
 974
 975       SSL.Abort_Undefer.all;
 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       SSL.Abort_Defer.all;
 986
 987       Result := pthread_mutex_lock (S.L'Access);
 988       pragma Assert (Result = 0);
 989
 990       --  If there is already a task waiting on this suspension object then
 991       --  we resume it, leaving the state of the suspension object to False,
 992       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
 993       --  the state to True.
 994
 995       if S.Waiting then
 996          S.Waiting := False;
 997          S.State := False;
 998
 999          Result := pthread_cond_signal (S.CV'Access);
1000          pragma Assert (Result = 0);
1001       else
1002          S.State := True;
1003       end if;
1004
1005       Result := pthread_mutex_unlock (S.L'Access);
1006       pragma Assert (Result = 0);
1007
1008       SSL.Abort_Undefer.all;
1009    end Set_True;
1010
1011    ------------------------
1012    -- Suspend_Until_True --
1013    ------------------------
1014
1015    procedure Suspend_Until_True (S : in out Suspension_Object) is
1016       Result : Interfaces.C.int;
1017    begin
1018       SSL.Abort_Defer.all;
1019
1020       Result := pthread_mutex_lock (S.L'Access);
1021       pragma Assert (Result = 0);
1022
1023       if S.Waiting then
1024          --  Program_Error must be raised upon calling Suspend_Until_True
1025          --  if another task is already waiting on that suspension object
1026          --  (ARM D.10 par. 10).
1027
1028          Result := pthread_mutex_unlock (S.L'Access);
1029          pragma Assert (Result = 0);
1030
1031          SSL.Abort_Undefer.all;
1032
1033          raise Program_Error;
1034       else
1035          --  Suspend the task if the state is False. Otherwise, the task
1036          --  continues its execution, and the state of the suspension object
1037          --  is set to False (ARM D.10 par. 9).
1038
1039          if S.State then
1040             S.State := False;
1041          else
1042             S.Waiting := True;
1043             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1044          end if;
1045
1046          Result := pthread_mutex_unlock (S.L'Access);
1047          pragma Assert (Result = 0);
1048
1049          SSL.Abort_Undefer.all;
1050       end if;
1051    end Suspend_Until_True;
1052
1053    ----------------
1054    -- Check_Exit --
1055    ----------------
1056
1057    --  Dummy version
1058
1059    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1060       pragma Unreferenced (Self_ID);
1061    begin
1062       return True;
1063    end Check_Exit;
1064
1065    --------------------
1066    -- Check_No_Locks --
1067    --------------------
1068
1069    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1070       pragma Unreferenced (Self_ID);
1071    begin
1072       return True;
1073    end Check_No_Locks;
1074
1075    ----------------------
1076    -- Environment_Task --
1077    ----------------------
1078
1079    function Environment_Task return Task_Id is
1080    begin
1081       return Environment_Task_Id;
1082    end Environment_Task;
1083
1084    --------------
1085    -- Lock_RTS --
1086    --------------
1087
1088    procedure Lock_RTS is
1089    begin
1090       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1091    end Lock_RTS;
1092
1093    ----------------
1094    -- Unlock_RTS --
1095    ----------------
1096
1097    procedure Unlock_RTS is
1098    begin
1099       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1100    end Unlock_RTS;
1101
1102    ------------------
1103    -- Suspend_Task --
1104    ------------------
1105
1106    function Suspend_Task
1107      (T           : ST.Task_Id;
1108       Thread_Self : Thread_Id) return Boolean
1109    is
1110       pragma Unreferenced (T);
1111       pragma Unreferenced (Thread_Self);
1112    begin
1113       return False;
1114    end Suspend_Task;
1115
1116    -----------------
1117    -- Resume_Task --
1118    -----------------
1119
1120    function Resume_Task
1121      (T           : ST.Task_Id;
1122       Thread_Self : Thread_Id) return Boolean
1123    is
1124       pragma Unreferenced (T);
1125       pragma Unreferenced (Thread_Self);
1126    begin
1127       return False;
1128    end Resume_Task;
1129
1130    ----------------
1131    -- Initialize --
1132    ----------------
1133
1134    procedure Initialize (Environment_Task : Task_Id) is
1135       act       : aliased struct_sigaction;
1136       old_act   : aliased struct_sigaction;
1137       Tmp_Set   : aliased sigset_t;
1138       Result    : Interfaces.C.int;
1139
1140       function State
1141         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1142       pragma Import (C, State, "__gnat_get_interrupt_state");
1143       --  Get interrupt state. Defined in a-init.c. The input argument is
1144       --  the interrupt number, and the result is one of the following:
1145
1146       Default : constant Character := 's';
1147       --    'n'   this interrupt not set by any Interrupt_State pragma
1148       --    'u'   Interrupt_State pragma set state to User
1149       --    'r'   Interrupt_State pragma set state to Runtime
1150       --    's'   Interrupt_State pragma set state to System (use "default"
1151       --           system handler)
1152
1153    begin
1154       Environment_Task_Id := Environment_Task;
1155
1156       Interrupt_Management.Initialize;
1157
1158       --  Initialize the lock used to synchronize chain of all ATCBs
1159
1160       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1161
1162       Specific.Initialize (Environment_Task);
1163
1164       Enter_Task (Environment_Task);
1165
1166       --  Install the abort-signal handler
1167
1168       if State (System.Interrupt_Management.Abort_Task_Interrupt)
1169                                                      /= Default
1170       then
1171          act.sa_flags := 0;
1172          act.sa_handler := Abort_Handler'Address;
1173
1174          Result := sigemptyset (Tmp_Set'Access);
1175          pragma Assert (Result = 0);
1176          act.sa_mask := Tmp_Set;
1177
1178          Result :=
1179            sigaction (
1180              Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1181              act'Unchecked_Access,
1182              old_act'Unchecked_Access);
1183          pragma Assert (Result = 0);
1184       end if;
1185    end Initialize;
1186
1187    --  NOTE: Unlike other pthread implementations, we do *not* mask all
1188    --  signals here since we handle signals using the process-wide primitive
1189    --  signal, rather than using sigthreadmask and sigwait. The reason of
1190    --  this difference is that sigwait doesn't work when some critical
1191    --  signals (SIGABRT, SIGPIPE) are masked.
1192
1193 end System.Task_Primitives.Operations;