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.Parameters;
  67 --  used for Size_Type
  68
  69 with System.Task_Primitives.Interrupt_Operations;
  70 --  used for Get_Interrupt_ID
  71
  72 with System.Soft_Links;
  73 --  used for Defer/Undefer_Abort
  74
  75 --  We use System.Soft_Links instead of System.Tasking.Initialization
  76 --  because the later is a higher level package that we shouldn't depend on.
  77 --  For example when using the restricted run time, it is replaced by
  78 --  System.Tasking.Restricted.Stages.
  79
  80 with Unchecked_Conversion;
  81 with Unchecked_Deallocation;
  82
  83 package body System.Task_Primitives.Operations is
  84
  85    package SSL renames System.Soft_Links;
  86
  87    use System.Tasking.Debug;
  88    use System.Tasking;
  89    use Interfaces.C;
  90    use System.OS_Interface;
  91    use System.Parameters;
  92    use System.OS_Primitives;
  93
  94    package PIO renames System.Task_Primitives.Interrupt_Operations;
  95
  96    ----------------
  97    -- Local Data --
  98    ----------------
  99
 100    --  The followings are logically constants, but need to be initialized
 101    --  at run time.
 102
 103    Single_RTS_Lock : aliased RTS_Lock;
 104    --  This is a lock to allow only one thread of control in the RTS at
 105    --  a time; it is used to execute in mutual exclusion from all other tasks.
 106    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
 107
 108    ATCB_Key : aliased pthread_key_t;
 109    --  Key used to find the Ada Task_Id associated with a thread
 110
 111    Environment_Task_Id : Task_Id;
 112    --  A variable to hold Task_Id for the environment task
 113
 114    Unblocked_Signal_Mask : aliased sigset_t;
 115    --  The set of signals that should unblocked in all tasks
 116
 117    Time_Slice_Val : Integer;
 118    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 119
 120    Dispatching_Policy : Character;
 121    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 122
 123    --  Note: the reason that Locking_Policy is not needed is that this
 124    --  is not implemented for DCE threads. The HPUX 10 port is at this
 125    --  stage considered dead, and no further work is planned on it.
 126
 127    Foreign_Task_Elaborated : aliased Boolean := True;
 128    --  Used to identified fake tasks (i.e., non-Ada Threads)
 129
 130    --------------------
 131    -- Local Packages --
 132    --------------------
 133
 134    package Specific is
 135
 136       procedure Initialize (Environment_Task : Task_Id);
 137       pragma Inline (Initialize);
 138       --  Initialize various data needed by this package
 139
 140       function Is_Valid_Task return Boolean;
 141       pragma Inline (Is_Valid_Task);
 142       --  Does the executing thread have a TCB?
 143
 144       procedure Set (Self_Id : Task_Id);
 145       pragma Inline (Set);
 146       --  Set the self id for the current task
 147
 148       function Self return Task_Id;
 149       pragma Inline (Self);
 150       --  Return a pointer to the Ada Task Control Block of the calling task
 151
 152    end Specific;
 153
 154    package body Specific is separate;
 155    --  The body of this package is target specific
 156
 157    ---------------------------------
 158    -- Support for foreign threads --
 159    ---------------------------------
 160
 161    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 162    --  Allocate and Initialize a new ATCB for the current Thread
 163
 164    function Register_Foreign_Thread
 165      (Thread : Thread_Id) return Task_Id is separate;
 166
 167    -----------------------
 168    -- Local Subprograms --
 169    -----------------------
 170
 171    procedure Abort_Handler (Sig : Signal);
 172
 173    function To_Address is new Unchecked_Conversion (Task_Id, System.Address);
 174
 175    -------------------
 176    -- Abort_Handler --
 177    -------------------
 178
 179    procedure Abort_Handler (Sig : Signal) is
 180       pragma Unreferenced (Sig);
 181
 182       Self_Id : constant Task_Id := Self;
 183       Result  : Interfaces.C.int;
 184       Old_Set : aliased sigset_t;
 185
 186    begin
 187       if Self_Id.Deferral_Level = 0
 188         and then Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level and then
 189         not Self_Id.Aborting
 190       then
 191          Self_Id.Aborting := True;
 192
 193          --  Make sure signals used for RTS internal purpose are unmasked
 194
 195          Result := pthread_sigmask (SIG_UNBLOCK,
 196            Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
 197          pragma Assert (Result = 0);
 198
 199          raise Standard'Abort_Signal;
 200       end if;
 201    end Abort_Handler;
 202
 203    -----------------
 204    -- Stack_Guard --
 205    -----------------
 206
 207    --  The underlying thread system sets a guard page at the
 208    --  bottom of a thread stack, so nothing is needed.
 209    --  ??? Check the comment above
 210
 211    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 212       pragma Unreferenced (T, On);
 213    begin
 214       null;
 215    end Stack_Guard;
 216
 217    -------------------
 218    -- Get_Thread_Id --
 219    -------------------
 220
 221    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 222    begin
 223       return T.Common.LL.Thread;
 224    end Get_Thread_Id;
 225
 226    ----------
 227    -- Self --
 228    ----------
 229
 230    function Self return Task_Id renames Specific.Self;
 231
 232    ---------------------
 233    -- Initialize_Lock --
 234    ---------------------
 235
 236    --  Note: mutexes and cond_variables needed per-task basis are
 237    --        initialized in Initialize_TCB and the Storage_Error is
 238    --        handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
 239    --        used in RTS is initialized before any status change of RTS.
 240    --        Therefore rasing Storage_Error in the following routines
 241    --        should be able to be handled safely.
 242
 243    procedure Initialize_Lock
 244      (Prio : System.Any_Priority;
 245       L    : access Lock)
 246    is
 247       Attributes : aliased pthread_mutexattr_t;
 248       Result     : Interfaces.C.int;
 249
 250    begin
 251       Result := pthread_mutexattr_init (Attributes'Access);
 252       pragma Assert (Result = 0 or else Result = ENOMEM);
 253
 254       if Result = ENOMEM then
 255          raise Storage_Error;
 256       end if;
 257
 258       L.Priority := Prio;
 259
 260       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 261       pragma Assert (Result = 0 or else Result = ENOMEM);
 262
 263       if Result = ENOMEM then
 264          raise Storage_Error;
 265       end if;
 266
 267       Result := pthread_mutexattr_destroy (Attributes'Access);
 268       pragma Assert (Result = 0);
 269    end Initialize_Lock;
 270
 271    procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
 272       pragma Unreferenced (Level);
 273
 274       Attributes : aliased pthread_mutexattr_t;
 275       Result     : Interfaces.C.int;
 276
 277    begin
 278       Result := pthread_mutexattr_init (Attributes'Access);
 279       pragma Assert (Result = 0 or else Result = ENOMEM);
 280
 281       if Result = ENOMEM then
 282          raise Storage_Error;
 283       end if;
 284
 285       Result := pthread_mutex_init (L, Attributes'Access);
 286
 287       pragma Assert (Result = 0 or else Result = ENOMEM);
 288
 289       if Result = ENOMEM then
 290          raise Storage_Error;
 291       end if;
 292
 293       Result := pthread_mutexattr_destroy (Attributes'Access);
 294       pragma Assert (Result = 0);
 295    end Initialize_Lock;
 296
 297    -------------------
 298    -- Finalize_Lock --
 299    -------------------
 300
 301    procedure Finalize_Lock (L : access Lock) is
 302       Result : Interfaces.C.int;
 303    begin
 304       Result := pthread_mutex_destroy (L.L'Access);
 305       pragma Assert (Result = 0);
 306    end Finalize_Lock;
 307
 308    procedure Finalize_Lock (L : access RTS_Lock) is
 309       Result : Interfaces.C.int;
 310    begin
 311       Result := pthread_mutex_destroy (L);
 312       pragma Assert (Result = 0);
 313    end Finalize_Lock;
 314
 315    ----------------
 316    -- Write_Lock --
 317    ----------------
 318
 319    procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 320       Result : Interfaces.C.int;
 321
 322    begin
 323       L.Owner_Priority := Get_Priority (Self);
 324
 325       if L.Priority < L.Owner_Priority then
 326          Ceiling_Violation := True;
 327          return;
 328       end if;
 329
 330       Result := pthread_mutex_lock (L.L'Access);
 331       pragma Assert (Result = 0);
 332       Ceiling_Violation := False;
 333    end Write_Lock;
 334
 335    procedure Write_Lock
 336      (L : access RTS_Lock; Global_Lock : Boolean := False)
 337    is
 338       Result : Interfaces.C.int;
 339    begin
 340       if not Single_Lock or else Global_Lock then
 341          Result := pthread_mutex_lock (L);
 342          pragma Assert (Result = 0);
 343       end if;
 344    end Write_Lock;
 345
 346    procedure Write_Lock (T : Task_Id) is
 347       Result : Interfaces.C.int;
 348    begin
 349       if not Single_Lock then
 350          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 351          pragma Assert (Result = 0);
 352       end if;
 353    end Write_Lock;
 354
 355    ---------------
 356    -- Read_Lock --
 357    ---------------
 358
 359    procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 360    begin
 361       Write_Lock (L, Ceiling_Violation);
 362    end Read_Lock;
 363
 364    ------------
 365    -- Unlock --
 366    ------------
 367
 368    procedure Unlock (L : access Lock) is
 369       Result : Interfaces.C.int;
 370    begin
 371       Result := pthread_mutex_unlock (L.L'Access);
 372       pragma Assert (Result = 0);
 373    end Unlock;
 374
 375    procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) 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    -- Sleep --
 395    -----------
 396
 397    procedure Sleep
 398      (Self_ID : Task_Id;
 399       Reason  : System.Tasking.Task_States)
 400    is
 401       pragma Unreferenced (Reason);
 402
 403       Result : Interfaces.C.int;
 404    begin
 405       if Single_Lock then
 406          Result := pthread_cond_wait
 407            (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 408       else
 409          Result := pthread_cond_wait
 410            (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 411       end if;
 412
 413       --  EINTR is not considered a failure
 414
 415       pragma Assert (Result = 0 or else Result = EINTR);
 416    end Sleep;
 417
 418    -----------------
 419    -- Timed_Sleep --
 420    -----------------
 421
 422    procedure Timed_Sleep
 423      (Self_ID  : Task_Id;
 424       Time     : Duration;
 425       Mode     : ST.Delay_Modes;
 426       Reason   : System.Tasking.Task_States;
 427       Timedout : out Boolean;
 428       Yielded  : out Boolean)
 429    is
 430       pragma Unreferenced (Reason);
 431
 432       Check_Time : constant Duration := Monotonic_Clock;
 433       Abs_Time   : Duration;
 434       Request    : aliased timespec;
 435       Result     : Interfaces.C.int;
 436
 437    begin
 438       Timedout := True;
 439       Yielded := False;
 440
 441       if Mode = Relative then
 442          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 443       else
 444          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 445       end if;
 446
 447       if Abs_Time > Check_Time then
 448          Request := To_Timespec (Abs_Time);
 449
 450          loop
 451             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 452               or else Self_ID.Pending_Priority_Change;
 453
 454             if Single_Lock then
 455                Result := pthread_cond_timedwait
 456                  (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
 457                   Request'Access);
 458
 459             else
 460                Result := pthread_cond_timedwait
 461                  (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
 462                   Request'Access);
 463             end if;
 464
 465             exit when Abs_Time <= Monotonic_Clock;
 466
 467             if Result = 0 or Result = EINTR then
 468
 469                --  Somebody may have called Wakeup for us
 470
 471                Timedout := False;
 472                exit;
 473             end if;
 474
 475             pragma Assert (Result = ETIMEDOUT);
 476          end loop;
 477       end if;
 478    end Timed_Sleep;
 479
 480    -----------------
 481    -- Timed_Delay --
 482    -----------------
 483
 484    procedure Timed_Delay
 485      (Self_ID  : Task_Id;
 486       Time     : Duration;
 487       Mode     : ST.Delay_Modes)
 488    is
 489       Check_Time : constant Duration := Monotonic_Clock;
 490       Abs_Time   : Duration;
 491       Request    : aliased timespec;
 492       Result     : Interfaces.C.int;
 493
 494    begin
 495       if Single_Lock then
 496          Lock_RTS;
 497       end if;
 498
 499       Write_Lock (Self_ID);
 500
 501       if Mode = Relative then
 502          Abs_Time := Time + Check_Time;
 503       else
 504          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 505       end if;
 506
 507       if Abs_Time > Check_Time then
 508          Request := To_Timespec (Abs_Time);
 509          Self_ID.Common.State := Delay_Sleep;
 510
 511          loop
 512             if Self_ID.Pending_Priority_Change then
 513                Self_ID.Pending_Priority_Change := False;
 514                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 515                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 516             end if;
 517
 518             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 519
 520             if Single_Lock then
 521                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 522                  Single_RTS_Lock'Access, Request'Access);
 523             else
 524                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 525                  Self_ID.Common.LL.L'Access, Request'Access);
 526             end if;
 527
 528             exit when Abs_Time <= Monotonic_Clock;
 529
 530             pragma Assert (Result = 0 or else
 531               Result = ETIMEDOUT or else
 532               Result = EINTR);
 533          end loop;
 534
 535          Self_ID.Common.State := Runnable;
 536       end if;
 537
 538       Unlock (Self_ID);
 539
 540       if Single_Lock then
 541          Unlock_RTS;
 542       end if;
 543
 544       Result := sched_yield;
 545    end Timed_Delay;
 546
 547    ---------------------
 548    -- Monotonic_Clock --
 549    ---------------------
 550
 551    function Monotonic_Clock return Duration is
 552       TS     : aliased timespec;
 553       Result : Interfaces.C.int;
 554    begin
 555       Result := Clock_Gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 556       pragma Assert (Result = 0);
 557       return To_Duration (TS);
 558    end Monotonic_Clock;
 559
 560    -------------------
 561    -- RT_Resolution --
 562    -------------------
 563
 564    function RT_Resolution return Duration is
 565    begin
 566       return 10#1.0#E-6;
 567    end RT_Resolution;
 568
 569    ------------
 570    -- Wakeup --
 571    ------------
 572
 573    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 574       pragma Unreferenced (Reason);
 575
 576       Result : Interfaces.C.int;
 577
 578    begin
 579       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 580       pragma Assert (Result = 0);
 581    end Wakeup;
 582
 583    -----------
 584    -- Yield --
 585    -----------
 586
 587    procedure Yield (Do_Yield : Boolean := True) is
 588       Result : Interfaces.C.int;
 589       pragma Unreferenced (Result);
 590    begin
 591       if Do_Yield then
 592          Result := sched_yield;
 593       end if;
 594    end Yield;
 595
 596    ------------------
 597    -- Set_Priority --
 598    ------------------
 599
 600    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 601    pragma Atomic_Components (Prio_Array_Type);
 602
 603    Prio_Array : Prio_Array_Type;
 604    --  Global array containing the id of the currently running task for
 605    --  each priority.
 606    --
 607    --  Note: we assume that we are on a single processor with run-til-blocked
 608    --  scheduling.
 609
 610    procedure Set_Priority
 611      (T                   : Task_Id;
 612       Prio                : System.Any_Priority;
 613       Loss_Of_Inheritance : Boolean := False)
 614    is
 615       Result     : Interfaces.C.int;
 616       Array_Item : Integer;
 617       Param      : aliased struct_sched_param;
 618
 619    begin
 620       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 621
 622       if Time_Slice_Val > 0 then
 623          Result := pthread_setschedparam
 624            (T.Common.LL.Thread, SCHED_RR, Param'Access);
 625
 626       elsif Dispatching_Policy = 'F' or else Time_Slice_Val = 0 then
 627          Result := pthread_setschedparam
 628            (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 629
 630       else
 631          Result := pthread_setschedparam
 632            (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 633       end if;
 634
 635       pragma Assert (Result = 0);
 636
 637       if Dispatching_Policy = 'F' then
 638
 639          --  Annex D requirement [RM D.2.2 par. 9]:
 640          --    If the task drops its priority due to the loss of inherited
 641          --    priority, it is added at the head of the ready queue for its
 642          --    new active priority.
 643
 644          if Loss_Of_Inheritance
 645            and then Prio < T.Common.Current_Priority
 646          then
 647             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 648             Prio_Array (T.Common.Base_Priority) := Array_Item;
 649
 650             loop
 651                --  Let some processes a chance to arrive
 652
 653                Yield;
 654
 655                --  Then wait for our turn to proceed
 656
 657                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 658                  or else Prio_Array (T.Common.Base_Priority) = 1;
 659             end loop;
 660
 661             Prio_Array (T.Common.Base_Priority) :=
 662               Prio_Array (T.Common.Base_Priority) - 1;
 663          end if;
 664       end if;
 665
 666       T.Common.Current_Priority := Prio;
 667    end Set_Priority;
 668
 669    ------------------
 670    -- Get_Priority --
 671    ------------------
 672
 673    function Get_Priority (T : Task_Id) return System.Any_Priority is
 674    begin
 675       return T.Common.Current_Priority;
 676    end Get_Priority;
 677
 678    ----------------
 679    -- Enter_Task --
 680    ----------------
 681
 682    procedure Enter_Task (Self_ID : Task_Id) is
 683    begin
 684       Self_ID.Common.LL.Thread := pthread_self;
 685       Specific.Set (Self_ID);
 686
 687       Lock_RTS;
 688
 689       for J in Known_Tasks'Range loop
 690          if Known_Tasks (J) = null then
 691             Known_Tasks (J) := Self_ID;
 692             Self_ID.Known_Tasks_Index := J;
 693             exit;
 694          end if;
 695       end loop;
 696
 697       Unlock_RTS;
 698    end Enter_Task;
 699
 700    --------------
 701    -- New_ATCB --
 702    --------------
 703
 704    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 705    begin
 706       return new Ada_Task_Control_Block (Entry_Num);
 707    end New_ATCB;
 708
 709    -------------------
 710    -- Is_Valid_Task --
 711    -------------------
 712
 713    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 714
 715    -----------------------------
 716    -- Register_Foreign_Thread --
 717    -----------------------------
 718
 719    function Register_Foreign_Thread return Task_Id is
 720    begin
 721       if Is_Valid_Task then
 722          return Self;
 723       else
 724          return Register_Foreign_Thread (pthread_self);
 725       end if;
 726    end Register_Foreign_Thread;
 727
 728    --------------------
 729    -- Initialize_TCB --
 730    --------------------
 731
 732    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 733       Mutex_Attr : aliased pthread_mutexattr_t;
 734       Result     : Interfaces.C.int;
 735       Cond_Attr  : aliased pthread_condattr_t;
 736
 737    begin
 738       if not Single_Lock then
 739          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 740          pragma Assert (Result = 0 or else Result = ENOMEM);
 741
 742          if Result = 0 then
 743             Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 744               Mutex_Attr'Access);
 745             pragma Assert (Result = 0 or else Result = ENOMEM);
 746          end if;
 747
 748          if Result /= 0 then
 749             Succeeded := False;
 750             return;
 751          end if;
 752
 753          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 754          pragma Assert (Result = 0);
 755       end if;
 756
 757       Result := pthread_condattr_init (Cond_Attr'Access);
 758       pragma Assert (Result = 0 or else Result = ENOMEM);
 759
 760       if Result = 0 then
 761          Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 762            Cond_Attr'Access);
 763          pragma Assert (Result = 0 or else Result = ENOMEM);
 764       end if;
 765
 766       if Result = 0 then
 767          Succeeded := True;
 768       else
 769          if not Single_Lock then
 770             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 771             pragma Assert (Result = 0);
 772          end if;
 773
 774          Succeeded := False;
 775       end if;
 776
 777       Result := pthread_condattr_destroy (Cond_Attr'Access);
 778       pragma Assert (Result = 0);
 779    end Initialize_TCB;
 780
 781    -----------------
 782    -- Create_Task --
 783    -----------------
 784
 785    procedure Create_Task
 786      (T          : Task_Id;
 787       Wrapper    : System.Address;
 788       Stack_Size : System.Parameters.Size_Type;
 789       Priority   : System.Any_Priority;
 790       Succeeded  : out Boolean)
 791    is
 792       Attributes : aliased pthread_attr_t;
 793       Result     : Interfaces.C.int;
 794
 795       function Thread_Body_Access is new
 796         Unchecked_Conversion (System.Address, Thread_Body);
 797
 798    begin
 799       Result := pthread_attr_init (Attributes'Access);
 800       pragma Assert (Result = 0 or else Result = ENOMEM);
 801
 802       if Result /= 0 then
 803          Succeeded := False;
 804          return;
 805       end if;
 806
 807       Result := pthread_attr_setstacksize
 808         (Attributes'Access, Interfaces.C.size_t (Stack_Size));
 809       pragma Assert (Result = 0);
 810
 811       --  Since the initial signal mask of a thread is inherited from the
 812       --  creator, and the Environment task has all its signals masked, we
 813       --  do not need to manipulate caller's signal mask at this point.
 814       --  All tasks in RTS will have All_Tasks_Mask initially.
 815
 816       Result := pthread_create
 817         (T.Common.LL.Thread'Access,
 818          Attributes'Access,
 819          Thread_Body_Access (Wrapper),
 820          To_Address (T));
 821       pragma Assert (Result = 0 or else Result = EAGAIN);
 822
 823       Succeeded := Result = 0;
 824
 825       pthread_detach (T.Common.LL.Thread'Access);
 826       --  Detach the thread using pthread_detach, sinc DCE threads do not have
 827       --  pthread_attr_set_detachstate.
 828
 829       Result := pthread_attr_destroy (Attributes'Access);
 830       pragma Assert (Result = 0);
 831
 832       Set_Priority (T, Priority);
 833    end Create_Task;
 834
 835    ------------------
 836    -- Finalize_TCB --
 837    ------------------
 838
 839    procedure Finalize_TCB (T : Task_Id) is
 840       Result  : Interfaces.C.int;
 841       Tmp     : Task_Id := T;
 842       Is_Self : constant Boolean := T = Self;
 843
 844       procedure Free is new
 845         Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 846
 847    begin
 848       if not Single_Lock then
 849          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 850          pragma Assert (Result = 0);
 851       end if;
 852
 853       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 854       pragma Assert (Result = 0);
 855
 856       if T.Known_Tasks_Index /= -1 then
 857          Known_Tasks (T.Known_Tasks_Index) := null;
 858       end if;
 859
 860       Free (Tmp);
 861
 862       if Is_Self then
 863          Specific.Set (null);
 864       end if;
 865    end Finalize_TCB;
 866
 867    ---------------
 868    -- Exit_Task --
 869    ---------------
 870
 871    procedure Exit_Task is
 872    begin
 873       Specific.Set (null);
 874    end Exit_Task;
 875
 876    ----------------
 877    -- Abort_Task --
 878    ----------------
 879
 880    procedure Abort_Task (T : Task_Id) is
 881    begin
 882       --
 883       --  Interrupt Server_Tasks may be waiting on an "event" flag (signal)
 884       --
 885       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 886          System.Interrupt_Management.Operations.Interrupt_Self_Process
 887            (System.Interrupt_Management.Interrupt_ID
 888              (PIO.Get_Interrupt_ID (T)));
 889       end if;
 890    end Abort_Task;
 891
 892    ----------------
 893    -- Initialize --
 894    ----------------
 895
 896    procedure Initialize (S : in out Suspension_Object) is
 897       Mutex_Attr : aliased pthread_mutexattr_t;
 898       Cond_Attr  : aliased pthread_condattr_t;
 899       Result     : Interfaces.C.int;
 900    begin
 901       --  Initialize internal state. It is always initialized to False (ARM
 902       --  D.10 par. 6).
 903
 904       S.State := False;
 905       S.Waiting := False;
 906
 907       --  Initialize internal mutex
 908
 909       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 910       pragma Assert (Result = 0 or else Result = ENOMEM);
 911
 912       if Result = ENOMEM then
 913          raise Storage_Error;
 914       end if;
 915
 916       --  Initialize internal condition variable
 917
 918       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 919       pragma Assert (Result = 0 or else Result = ENOMEM);
 920
 921       if Result /= 0 then
 922          Result := pthread_mutex_destroy (S.L'Access);
 923          pragma Assert (Result = 0);
 924
 925          if Result = ENOMEM then
 926             raise Storage_Error;
 927          end if;
 928       end if;
 929    end Initialize;
 930
 931    --------------
 932    -- Finalize --
 933    --------------
 934
 935    procedure Finalize (S : in out Suspension_Object) is
 936       Result  : Interfaces.C.int;
 937    begin
 938       --  Destroy internal mutex
 939
 940       Result := pthread_mutex_destroy (S.L'Access);
 941       pragma Assert (Result = 0);
 942
 943       --  Destroy internal condition variable
 944
 945       Result := pthread_cond_destroy (S.CV'Access);
 946       pragma Assert (Result = 0);
 947    end Finalize;
 948
 949    -------------------
 950    -- Current_State --
 951    -------------------
 952
 953    function Current_State (S : Suspension_Object) return Boolean is
 954    begin
 955       --  We do not want to use lock on this read operation. State is marked
 956       --  as Atomic so that we ensure that the value retrieved is correct.
 957
 958       return S.State;
 959    end Current_State;
 960
 961    ---------------
 962    -- Set_False --
 963    ---------------
 964
 965    procedure Set_False (S : in out Suspension_Object) is
 966       Result  : Interfaces.C.int;
 967    begin
 968       SSL.Abort_Defer.all;
 969
 970       Result := pthread_mutex_lock (S.L'Access);
 971       pragma Assert (Result = 0);
 972
 973       S.State := False;
 974
 975       Result := pthread_mutex_unlock (S.L'Access);
 976       pragma Assert (Result = 0);
 977
 978       SSL.Abort_Undefer.all;
 979    end Set_False;
 980
 981    --------------
 982    -- Set_True --
 983    --------------
 984
 985    procedure Set_True (S : in out Suspension_Object) is
 986       Result : Interfaces.C.int;
 987    begin
 988       SSL.Abort_Defer.all;
 989
 990       Result := pthread_mutex_lock (S.L'Access);
 991       pragma Assert (Result = 0);
 992
 993       --  If there is already a task waiting on this suspension object then
 994       --  we resume it, leaving the state of the suspension object to False,
 995       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
 996       --  the state to True.
 997
 998       if S.Waiting then
 999          S.Waiting := False;
1000          S.State := False;
1001
1002          Result := pthread_cond_signal (S.CV'Access);
1003          pragma Assert (Result = 0);
1004       else
1005          S.State := True;
1006       end if;
1007
1008       Result := pthread_mutex_unlock (S.L'Access);
1009       pragma Assert (Result = 0);
1010
1011       SSL.Abort_Undefer.all;
1012    end Set_True;
1013
1014    ------------------------
1015    -- Suspend_Until_True --
1016    ------------------------
1017
1018    procedure Suspend_Until_True (S : in out Suspension_Object) is
1019       Result : Interfaces.C.int;
1020    begin
1021       SSL.Abort_Defer.all;
1022
1023       Result := pthread_mutex_lock (S.L'Access);
1024       pragma Assert (Result = 0);
1025
1026       if S.Waiting then
1027          --  Program_Error must be raised upon calling Suspend_Until_True
1028          --  if another task is already waiting on that suspension object
1029          --  (ARM D.10 par. 10).
1030
1031          Result := pthread_mutex_unlock (S.L'Access);
1032          pragma Assert (Result = 0);
1033
1034          SSL.Abort_Undefer.all;
1035
1036          raise Program_Error;
1037       else
1038          --  Suspend the task if the state is False. Otherwise, the task
1039          --  continues its execution, and the state of the suspension object
1040          --  is set to False (ARM D.10 par. 9).
1041
1042          if S.State then
1043             S.State := False;
1044          else
1045             S.Waiting := True;
1046             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1047          end if;
1048
1049          Result := pthread_mutex_unlock (S.L'Access);
1050          pragma Assert (Result = 0);
1051
1052          SSL.Abort_Undefer.all;
1053       end if;
1054    end Suspend_Until_True;
1055
1056    ----------------
1057    -- Check_Exit --
1058    ----------------
1059
1060    --  Dummy version
1061
1062    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1063       pragma Unreferenced (Self_ID);
1064    begin
1065       return True;
1066    end Check_Exit;
1067
1068    --------------------
1069    -- Check_No_Locks --
1070    --------------------
1071
1072    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1073       pragma Unreferenced (Self_ID);
1074    begin
1075       return True;
1076    end Check_No_Locks;
1077
1078    ----------------------
1079    -- Environment_Task --
1080    ----------------------
1081
1082    function Environment_Task return Task_Id is
1083    begin
1084       return Environment_Task_Id;
1085    end Environment_Task;
1086
1087    --------------
1088    -- Lock_RTS --
1089    --------------
1090
1091    procedure Lock_RTS is
1092    begin
1093       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1094    end Lock_RTS;
1095
1096    ----------------
1097    -- Unlock_RTS --
1098    ----------------
1099
1100    procedure Unlock_RTS is
1101    begin
1102       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1103    end Unlock_RTS;
1104
1105    ------------------
1106    -- Suspend_Task --
1107    ------------------
1108
1109    function Suspend_Task
1110      (T           : ST.Task_Id;
1111       Thread_Self : Thread_Id) return Boolean
1112    is
1113       pragma Unreferenced (T);
1114       pragma Unreferenced (Thread_Self);
1115    begin
1116       return False;
1117    end Suspend_Task;
1118
1119    -----------------
1120    -- Resume_Task --
1121    -----------------
1122
1123    function Resume_Task
1124      (T           : ST.Task_Id;
1125       Thread_Self : Thread_Id) return Boolean
1126    is
1127       pragma Unreferenced (T);
1128       pragma Unreferenced (Thread_Self);
1129    begin
1130       return False;
1131    end Resume_Task;
1132
1133    ----------------
1134    -- Initialize --
1135    ----------------
1136
1137    procedure Initialize (Environment_Task : Task_Id) is
1138       act       : aliased struct_sigaction;
1139       old_act   : aliased struct_sigaction;
1140       Tmp_Set   : aliased sigset_t;
1141       Result    : Interfaces.C.int;
1142
1143       function State
1144         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1145       pragma Import (C, State, "__gnat_get_interrupt_state");
1146       --  Get interrupt state. Defined in a-init.c. The input argument is
1147       --  the interrupt number, and the result is one of the following:
1148
1149       Default : constant Character := 's';
1150       --    'n'   this interrupt not set by any Interrupt_State pragma
1151       --    'u'   Interrupt_State pragma set state to User
1152       --    'r'   Interrupt_State pragma set state to Runtime
1153       --    's'   Interrupt_State pragma set state to System (use "default"
1154       --           system handler)
1155
1156    begin
1157       Environment_Task_Id := Environment_Task;
1158
1159       Interrupt_Management.Initialize;
1160
1161       --  Initialize the lock used to synchronize chain of all ATCBs
1162
1163       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1164
1165       Specific.Initialize (Environment_Task);
1166
1167       Enter_Task (Environment_Task);
1168
1169       --  Install the abort-signal handler
1170
1171       if State (System.Interrupt_Management.Abort_Task_Interrupt)
1172                                                      /= Default
1173       then
1174          act.sa_flags := 0;
1175          act.sa_handler := Abort_Handler'Address;
1176
1177          Result := sigemptyset (Tmp_Set'Access);
1178          pragma Assert (Result = 0);
1179          act.sa_mask := Tmp_Set;
1180
1181          Result :=
1182            sigaction (
1183              Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1184              act'Unchecked_Access,
1185              old_act'Unchecked_Access);
1186          pragma Assert (Result = 0);
1187       end if;
1188    end Initialize;
1189
1190    --  NOTE: Unlike other pthread implementations, we do *not* mask all
1191    --  signals here since we handle signals using the process-wide primitive
1192    --  signal, rather than using sigthreadmask and sigwait. The reason of
1193    --  this difference is that sigwait doesn't work when some critical
1194    --  signals (SIGABRT, SIGPIPE) are masked.
1195
1196 end System.Task_Primitives.Operations;