gcc/ada/5ataprop.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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 --                                                                          --
  10 --         Copyright (C) 1992-2001, Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com).     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This is a DEC Unix 4.0d version of this package
  36
  37 --  This package contains all the GNULL primitives that interface directly
  38 --  with the underlying OS.
  39
  40 pragma Polling (Off);
  41 --  Turn off polling, we do not want ATC polling to take place during
  42 --  tasking operations. It causes infinite loops and other problems.
  43
  44 with System.Tasking.Debug;
  45 --  used for Known_Tasks
  46
  47 with System.Task_Info;
  48 --  used for Task_Info_Type
  49
  50 with Interfaces;
  51 --  used for Shift_Left
  52
  53 with Interfaces.C;
  54 --  used for int
  55 --           size_t
  56
  57 with System.Interrupt_Management;
  58 --  used for Keep_Unmasked
  59 --           Abort_Task_Interrupt
  60 --           Interrupt_ID
  61
  62 with System.Interrupt_Management.Operations;
  63 --  used for Set_Interrupt_Mask
  64 --           All_Tasks_Mask
  65 pragma Elaborate_All (System.Interrupt_Management.Operations);
  66
  67 with System.Parameters;
  68 --  used for Size_Type
  69
  70 with System.Tasking;
  71 --  used for Ada_Task_Control_Block
  72 --           Task_ID
  73 --           ATCB components and types
  74
  75 with System.Soft_Links;
  76 --  used for Defer/Undefer_Abort
  77
  78 --  Note that we do not use System.Tasking.Initialization directly since
  79 --  this is a higher level package that we shouldn't depend on. For example
  80 --  when using the restricted run time, it is replaced by
  81 --  System.Tasking.Restricted.Initialization
  82
  83 with System.OS_Primitives;
  84 --  used for Delay_Modes
  85
  86 with Unchecked_Conversion;
  87 with Unchecked_Deallocation;
  88
  89 package body System.Task_Primitives.Operations is
  90
  91    use System.Tasking.Debug;
  92    use System.Tasking;
  93    use Interfaces.C;
  94    use System.OS_Interface;
  95    use System.Parameters;
  96    use System.OS_Primitives;
  97
  98    package SSL renames System.Soft_Links;
  99
 100    ----------------
 101    -- Local Data --
 102    ----------------
 103
 104    --  The followings are logically constants, but need to be initialized
 105    --  at run time.
 106
 107    Single_RTS_Lock : aliased RTS_Lock;
 108    --  This is a lock to allow only one thread of control in the RTS at
 109    --  a time; it is used to execute in mutual exclusion from all other tasks.
 110    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
 111
 112    Environment_Task_ID : Task_ID;
 113    --  A variable to hold Task_ID for the environment task.
 114
 115    Unblocked_Signal_Mask : aliased sigset_t;
 116    --  The set of signals that should unblocked in all tasks
 117
 118    Time_Slice_Val : Integer;
 119    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 120
 121    Locking_Policy : Character;
 122    pragma Import (C, Locking_Policy, "__gl_locking_policy");
 123
 124    Dispatching_Policy : Character;
 125    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 126
 127    FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
 128    --  Indicates whether FIFO_Within_Priorities is set.
 129
 130    Curpid : pid_t;
 131
 132    -----------------------
 133    -- Local Subprograms --
 134    -----------------------
 135
 136    procedure Abort_Handler (Sig : Signal);
 137
 138    function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
 139
 140    function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
 141
 142    --------------------
 143    -- Local Packages --
 144    --------------------
 145
 146    package Specific is
 147
 148       procedure Initialize (Environment_Task : Task_ID);
 149       pragma Inline (Initialize);
 150       --  Initialize various data needed by this package.
 151
 152       procedure Set (Self_Id : Task_ID);
 153       pragma Inline (Set);
 154       --  Set the self id for the current task.
 155
 156       function Self return Task_ID;
 157       pragma Inline (Self);
 158       --  Return a pointer to the Ada Task Control Block of the calling task.
 159
 160    end Specific;
 161
 162    package body Specific is separate;
 163    --  The body of this package is target specific.
 164
 165    -------------------
 166    -- Abort_Handler --
 167    -------------------
 168
 169    procedure Abort_Handler (Sig : Signal) is
 170       T       : constant Task_ID := Self;
 171       Result  : Interfaces.C.int;
 172       Old_Set : aliased sigset_t;
 173
 174    begin
 175       if T.Deferral_Level = 0
 176         and then T.Pending_ATC_Level < T.ATC_Nesting_Level and then
 177         not T.Aborting
 178       then
 179          T.Aborting := True;
 180
 181          --  Make sure signals used for RTS internal purpose are unmasked
 182
 183          Result := pthread_sigmask (SIG_UNBLOCK,
 184            Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
 185          pragma Assert (Result = 0);
 186
 187          raise Standard'Abort_Signal;
 188       end if;
 189    end Abort_Handler;
 190
 191    ------------------
 192    -- Stack_Guard  --
 193    ------------------
 194
 195    --  The underlying thread system sets a guard page at the
 196    --  bottom of a thread stack, so nothing is needed.
 197
 198    procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
 199    begin
 200       null;
 201    end Stack_Guard;
 202
 203    --------------------
 204    -- Get_Thread_Id  --
 205    --------------------
 206
 207    function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
 208    begin
 209       return T.Common.LL.Thread;
 210    end Get_Thread_Id;
 211
 212    ----------
 213    -- Self --
 214    ----------
 215
 216    function Self return Task_ID renames Specific.Self;
 217
 218    ---------------------
 219    -- Initialize_Lock --
 220    ---------------------
 221
 222    --  Note: mutexes and cond_variables needed per-task basis are
 223    --        initialized in Initialize_TCB and the Storage_Error is
 224    --        handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
 225    --        used in RTS is initialized before any status change of RTS.
 226    --        Therefore rasing Storage_Error in the following routines
 227    --        should be able to be handled safely.
 228
 229    procedure Initialize_Lock
 230      (Prio : System.Any_Priority;
 231       L    : access Lock)
 232    is
 233       Attributes : aliased pthread_mutexattr_t;
 234       Result     : Interfaces.C.int;
 235
 236    begin
 237       Result := pthread_mutexattr_init (Attributes'Access);
 238       pragma Assert (Result = 0 or else Result = ENOMEM);
 239
 240       if Result = ENOMEM then
 241          raise Storage_Error;
 242       end if;
 243
 244       if Locking_Policy = 'C' then
 245          L.Ceiling := Interfaces.C.int (Prio);
 246       end if;
 247
 248       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 249       pragma Assert (Result = 0 or else Result = ENOMEM);
 250
 251       if Result = ENOMEM then
 252          Result := pthread_mutexattr_destroy (Attributes'Access);
 253          raise Storage_Error;
 254       end if;
 255
 256       Result := pthread_mutexattr_destroy (Attributes'Access);
 257       pragma Assert (Result = 0);
 258    end Initialize_Lock;
 259
 260    procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
 261       Attributes : aliased pthread_mutexattr_t;
 262       Result     : Interfaces.C.int;
 263
 264    begin
 265       Result := pthread_mutexattr_init (Attributes'Access);
 266       pragma Assert (Result = 0 or else Result = ENOMEM);
 267
 268       if Result = ENOMEM then
 269          raise Storage_Error;
 270       end if;
 271
 272       Result := pthread_mutex_init (L, Attributes'Access);
 273       pragma Assert (Result = 0 or else Result = ENOMEM);
 274
 275       if Result = ENOMEM then
 276          Result := pthread_mutexattr_destroy (Attributes'Access);
 277          raise Storage_Error;
 278       end if;
 279
 280       Result := pthread_mutexattr_destroy (Attributes'Access);
 281       pragma Assert (Result = 0);
 282    end Initialize_Lock;
 283
 284    -------------------
 285    -- Finalize_Lock --
 286    -------------------
 287
 288    procedure Finalize_Lock (L : access Lock) is
 289       Result : Interfaces.C.int;
 290    begin
 291       Result := pthread_mutex_destroy (L.L'Access);
 292       pragma Assert (Result = 0);
 293    end Finalize_Lock;
 294
 295    procedure Finalize_Lock (L : access RTS_Lock) is
 296       Result : Interfaces.C.int;
 297    begin
 298       Result := pthread_mutex_destroy (L);
 299       pragma Assert (Result = 0);
 300    end Finalize_Lock;
 301
 302    ----------------
 303    -- Write_Lock --
 304    ----------------
 305
 306    procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 307       Result         : Interfaces.C.int;
 308       Self_ID        : Task_ID;
 309       All_Tasks_Link : Task_ID;
 310       Current_Prio   : System.Any_Priority;
 311
 312    begin
 313       --  Perform ceiling checks only when this is the locking policy in use.
 314
 315       if Locking_Policy = 'C' then
 316          Self_ID := Self;
 317          All_Tasks_Link := Self_ID.Common.All_Tasks_Link;
 318          Current_Prio := Get_Priority (Self_ID);
 319
 320          --  If there is no other task, no need to check priorities
 321
 322          if All_Tasks_Link /= Null_Task
 323            and then L.Ceiling < Interfaces.C.int (Current_Prio)
 324          then
 325             Ceiling_Violation := True;
 326             return;
 327          end if;
 328       end if;
 329
 330       Result := pthread_mutex_lock (L.L'Access);
 331       pragma Assert (Result = 0);
 332
 333       Ceiling_Violation := False;
 334    end Write_Lock;
 335
 336    procedure Write_Lock
 337      (L : access RTS_Lock; Global_Lock : Boolean := False)
 338    is
 339       Result : Interfaces.C.int;
 340    begin
 341       if not Single_Lock or else Global_Lock then
 342          Result := pthread_mutex_lock (L);
 343          pragma Assert (Result = 0);
 344       end if;
 345    end Write_Lock;
 346
 347    procedure Write_Lock (T : Task_ID) is
 348       Result : Interfaces.C.int;
 349    begin
 350       if not Single_Lock then
 351          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 352          pragma Assert (Result = 0);
 353       end if;
 354    end Write_Lock;
 355
 356    ---------------
 357    -- Read_Lock --
 358    ---------------
 359
 360    procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
 361    begin
 362       Write_Lock (L, Ceiling_Violation);
 363    end Read_Lock;
 364
 365    ------------
 366    -- Unlock --
 367    ------------
 368
 369    procedure Unlock (L : access Lock) is
 370       Result : Interfaces.C.int;
 371    begin
 372       Result := pthread_mutex_unlock (L.L'Access);
 373       pragma Assert (Result = 0);
 374    end Unlock;
 375
 376    procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
 377       Result : Interfaces.C.int;
 378    begin
 379       if not Single_Lock or else Global_Lock then
 380          Result := pthread_mutex_unlock (L);
 381          pragma Assert (Result = 0);
 382       end if;
 383    end Unlock;
 384
 385    procedure Unlock (T : Task_ID) is
 386       Result : Interfaces.C.int;
 387    begin
 388       if not Single_Lock then
 389          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 390          pragma Assert (Result = 0);
 391       end if;
 392    end Unlock;
 393
 394    -----------
 395    -- Sleep --
 396    -----------
 397
 398    procedure Sleep
 399      (Self_ID : Task_ID;
 400       Reason  : System.Tasking.Task_States)
 401    is
 402       Result : Interfaces.C.int;
 403    begin
 404       if Single_Lock then
 405          Result := pthread_cond_wait
 406            (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 407       else
 408          Result := pthread_cond_wait
 409            (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 410       end if;
 411
 412       --  EINTR is not considered a failure.
 413
 414       pragma Assert (Result = 0 or else Result = EINTR);
 415    end Sleep;
 416
 417    -----------------
 418    -- Timed_Sleep --
 419    -----------------
 420
 421    --  This is for use within the run-time system, so abort is
 422    --  assumed to be already deferred, and the caller should be
 423    --  holding its own ATCB lock.
 424
 425    procedure Timed_Sleep
 426      (Self_ID  : Task_ID;
 427       Time     : Duration;
 428       Mode     : ST.Delay_Modes;
 429       Reason   : System.Tasking.Task_States;
 430       Timedout : out Boolean;
 431       Yielded  : out Boolean)
 432    is
 433       Check_Time : constant Duration := Monotonic_Clock;
 434       Abs_Time   : Duration;
 435       Request    : aliased timespec;
 436       Result     : Interfaces.C.int;
 437
 438    begin
 439       Timedout := True;
 440       Yielded := False;
 441
 442       if Mode = Relative then
 443          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 444       else
 445          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 446       end if;
 447
 448       if Abs_Time > Check_Time then
 449          Request := To_Timespec (Abs_Time);
 450
 451          loop
 452             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 453               or else Self_ID.Pending_Priority_Change;
 454
 455             if Single_Lock then
 456                Result := pthread_cond_timedwait
 457                  (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
 458                   Request'Access);
 459
 460             else
 461                Result := pthread_cond_timedwait
 462                  (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
 463                   Request'Access);
 464             end if;
 465
 466             exit when Abs_Time <= Monotonic_Clock;
 467
 468             if Result = 0 or Result = EINTR then
 469                --  somebody may have called Wakeup for us
 470                Timedout := False;
 471                exit;
 472             end if;
 473
 474             pragma Assert (Result = ETIMEDOUT);
 475          end loop;
 476       end if;
 477    end Timed_Sleep;
 478
 479    -----------------
 480    -- Timed_Delay --
 481    -----------------
 482
 483    --  This is for use in implementing delay statements, so
 484    --  we assume the caller is abort-deferred but is holding
 485    --  no locks.
 486
 487    procedure Timed_Delay
 488      (Self_ID  : Task_ID;
 489       Time     : Duration;
 490       Mode     : ST.Delay_Modes)
 491    is
 492       Check_Time : constant Duration := Monotonic_Clock;
 493       Abs_Time   : Duration;
 494       Request    : aliased timespec;
 495       Result     : Interfaces.C.int;
 496
 497    begin
 498       --  Only the little window between deferring abort and
 499       --  locking Self_ID is the reason we need to
 500       --  check for pending abort and priority change below! :(
 501
 502       SSL.Abort_Defer.all;
 503
 504       if Single_Lock then
 505          Lock_RTS;
 506       end if;
 507
 508       Write_Lock (Self_ID);
 509
 510       if Mode = Relative then
 511          Abs_Time := Time + Check_Time;
 512       else
 513          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 514       end if;
 515
 516       if Abs_Time > Check_Time then
 517          Request := To_Timespec (Abs_Time);
 518          Self_ID.Common.State := Delay_Sleep;
 519
 520          loop
 521             if Self_ID.Pending_Priority_Change then
 522                Self_ID.Pending_Priority_Change := False;
 523                Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
 524                Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
 525             end if;
 526
 527             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 528
 529             if Single_Lock then
 530                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 531                  Single_RTS_Lock'Access, Request'Access);
 532             else
 533                Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
 534                  Self_ID.Common.LL.L'Access, Request'Access);
 535             end if;
 536
 537             exit when Abs_Time <= Monotonic_Clock;
 538
 539             pragma Assert (Result = 0 or else
 540               Result = ETIMEDOUT or else
 541               Result = EINTR);
 542          end loop;
 543
 544          Self_ID.Common.State := Runnable;
 545       end if;
 546
 547       Unlock (Self_ID);
 548
 549       if Single_Lock then
 550          Unlock_RTS;
 551       end if;
 552
 553       Yield;
 554       SSL.Abort_Undefer.all;
 555    end Timed_Delay;
 556
 557    ---------------------
 558    -- Monotonic_Clock --
 559    ---------------------
 560
 561    function Monotonic_Clock return Duration is
 562       TS     : aliased timespec;
 563       Result : Interfaces.C.int;
 564
 565    begin
 566       Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 567       pragma Assert (Result = 0);
 568       return To_Duration (TS);
 569    end Monotonic_Clock;
 570
 571    -------------------
 572    -- RT_Resolution --
 573    -------------------
 574
 575    function RT_Resolution return Duration is
 576    begin
 577       return 1.0 / 1024.0; --  Clock on DEC Alpha ticks at 1024 Hz
 578    end RT_Resolution;
 579
 580    ------------
 581    -- Wakeup --
 582    ------------
 583
 584    procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is
 585       Result : Interfaces.C.int;
 586    begin
 587       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 588       pragma Assert (Result = 0);
 589    end Wakeup;
 590
 591    -----------
 592    -- Yield --
 593    -----------
 594
 595    procedure Yield (Do_Yield : Boolean := True) is
 596       Result : Interfaces.C.int;
 597    begin
 598       if Do_Yield then
 599          Result := sched_yield;
 600       end if;
 601    end Yield;
 602
 603    ------------------
 604    -- Set_Priority --
 605    ------------------
 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       Param  : aliased struct_sched_param;
 614
 615    begin
 616       T.Common.Current_Priority := Prio;
 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 FIFO_Within_Priorities 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    end Set_Priority;
 634
 635    ------------------
 636    -- Get_Priority --
 637    ------------------
 638
 639    function Get_Priority (T : Task_ID) return System.Any_Priority is
 640    begin
 641       return T.Common.Current_Priority;
 642    end Get_Priority;
 643
 644    ----------------
 645    -- Enter_Task --
 646    ----------------
 647
 648    procedure Enter_Task (Self_ID : Task_ID) is
 649    begin
 650       Self_ID.Common.LL.Thread := pthread_self;
 651       Specific.Set (Self_ID);
 652
 653       Lock_RTS;
 654
 655       for J in Known_Tasks'Range loop
 656          if Known_Tasks (J) = null then
 657             Known_Tasks (J) := Self_ID;
 658             Self_ID.Known_Tasks_Index := J;
 659             exit;
 660          end if;
 661       end loop;
 662
 663       Unlock_RTS;
 664    end Enter_Task;
 665
 666    --------------
 667    -- New_ATCB --
 668    --------------
 669
 670    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
 671    begin
 672       return new Ada_Task_Control_Block (Entry_Num);
 673    end New_ATCB;
 674
 675    --------------------
 676    -- Initialize_TCB --
 677    --------------------
 678
 679    procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
 680       Mutex_Attr : aliased pthread_mutexattr_t;
 681       Result     : Interfaces.C.int;
 682       Cond_Attr  : aliased pthread_condattr_t;
 683
 684    begin
 685       if not Single_Lock then
 686          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 687          pragma Assert (Result = 0 or else Result = ENOMEM);
 688
 689          if Result = 0 then
 690             Result := pthread_mutex_init (Self_ID.Common.LL.L'Access,
 691               Mutex_Attr'Access);
 692             pragma Assert (Result = 0 or else Result = ENOMEM);
 693          end if;
 694
 695          if Result /= 0 then
 696             Succeeded := False;
 697             return;
 698          end if;
 699
 700          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 701          pragma Assert (Result = 0);
 702       end if;
 703
 704       Result := pthread_condattr_init (Cond_Attr'Access);
 705       pragma Assert (Result = 0 or else Result = ENOMEM);
 706
 707       if Result = 0 then
 708          Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
 709            Cond_Attr'Access);
 710          pragma Assert (Result = 0 or else Result = ENOMEM);
 711       end if;
 712
 713       if Result = 0 then
 714          Succeeded := True;
 715       else
 716          if not Single_Lock then
 717             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 718             pragma Assert (Result = 0);
 719          end if;
 720
 721          Succeeded := False;
 722       end if;
 723
 724       Result := pthread_condattr_destroy (Cond_Attr'Access);
 725       pragma Assert (Result = 0);
 726    end Initialize_TCB;
 727
 728    -----------------
 729    -- Create_Task --
 730    -----------------
 731
 732    procedure Create_Task
 733      (T          : Task_ID;
 734       Wrapper    : System.Address;
 735       Stack_Size : System.Parameters.Size_Type;
 736       Priority   : System.Any_Priority;
 737       Succeeded  : out Boolean)
 738    is
 739       Attributes          : aliased pthread_attr_t;
 740       Adjusted_Stack_Size : Interfaces.C.size_t;
 741       Result              : Interfaces.C.int;
 742       Param               : aliased System.OS_Interface.struct_sched_param;
 743
 744       function Thread_Body_Access is new
 745         Unchecked_Conversion (System.Address, Thread_Body);
 746
 747       use System.Task_Info;
 748
 749    begin
 750       if Stack_Size = Unspecified_Size then
 751          Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size);
 752
 753       elsif Stack_Size < Minimum_Stack_Size then
 754          Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size);
 755
 756       else
 757          Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
 758       end if;
 759
 760       Result := pthread_attr_init (Attributes'Access);
 761       pragma Assert (Result = 0 or else Result = ENOMEM);
 762
 763       if Result /= 0 then
 764          Succeeded := False;
 765          return;
 766       end if;
 767
 768       Result := pthread_attr_setdetachstate
 769         (Attributes'Access, PTHREAD_CREATE_DETACHED);
 770       pragma Assert (Result = 0);
 771
 772       Result := pthread_attr_setstacksize
 773         (Attributes'Access, Adjusted_Stack_Size);
 774       pragma Assert (Result = 0);
 775
 776       --  Set the scheduling parameters explicitly, since this is the only
 777       --  way to force the OS to take the scope attribute into account
 778
 779       Result := pthread_attr_setinheritsched
 780         (Attributes'Access, PTHREAD_EXPLICIT_SCHED);
 781       pragma Assert (Result = 0);
 782
 783       Param.sched_priority :=
 784         Interfaces.C.int (Underlying_Priorities (Priority));
 785       Result := pthread_attr_setschedparam
 786         (Attributes'Access, Param'Access);
 787       pragma Assert (Result = 0);
 788
 789       if Time_Slice_Val > 0 then
 790          Result := pthread_attr_setschedpolicy
 791            (Attributes'Access, System.OS_Interface.SCHED_RR);
 792
 793       elsif FIFO_Within_Priorities or else Time_Slice_Val = 0 then
 794          Result := pthread_attr_setschedpolicy
 795            (Attributes'Access, System.OS_Interface.SCHED_FIFO);
 796
 797       else
 798          Result := pthread_attr_setschedpolicy
 799            (Attributes'Access, System.OS_Interface.SCHED_OTHER);
 800       end if;
 801
 802       pragma Assert (Result = 0);
 803
 804       T.Common.Current_Priority := Priority;
 805
 806       if T.Common.Task_Info /= null then
 807          case T.Common.Task_Info.Contention_Scope is
 808             when System.Task_Info.Process_Scope =>
 809                Result := pthread_attr_setscope
 810                   (Attributes'Access, PTHREAD_SCOPE_PROCESS);
 811
 812             when System.Task_Info.System_Scope =>
 813                Result := pthread_attr_setscope
 814                   (Attributes'Access, PTHREAD_SCOPE_SYSTEM);
 815
 816             when System.Task_Info.Default_Scope =>
 817                Result := 0;
 818          end case;
 819
 820          pragma Assert (Result = 0);
 821       end if;
 822
 823       --  Since the initial signal mask of a thread is inherited from the
 824       --  creator, and the Environment task has all its signals masked, we
 825       --  do not need to manipulate caller's signal mask at this point.
 826       --  All tasks in RTS will have All_Tasks_Mask initially.
 827
 828       Result := pthread_create
 829         (T.Common.LL.Thread'Access,
 830          Attributes'Access,
 831          Thread_Body_Access (Wrapper),
 832          To_Address (T));
 833       pragma Assert (Result = 0 or else Result = EAGAIN);
 834
 835       Succeeded := Result = 0;
 836
 837       Result := pthread_attr_destroy (Attributes'Access);
 838       pragma Assert (Result = 0);
 839
 840       if T.Common.Task_Info /= null then
 841          if T.Common.Task_Info.Bind_To_Cpu_Number = 0 then
 842             Result := bind_to_cpu (Curpid, 0);
 843          elsif T.Common.Task_Info.Bind_To_Cpu_Number > 0 then
 844             Result := bind_to_cpu
 845               (Curpid,
 846                Interfaces.C.unsigned_long (
 847                  Interfaces.Shift_Left
 848                    (Interfaces.Unsigned_64'(1),
 849                     T.Common.Task_Info.Bind_To_Cpu_Number - 1)));
 850             pragma Assert (Result = 0);
 851          end if;
 852       end if;
 853    end Create_Task;
 854
 855    ------------------
 856    -- Finalize_TCB --
 857    ------------------
 858
 859    procedure Finalize_TCB (T : Task_ID) is
 860       Result : Interfaces.C.int;
 861       Tmp    : Task_ID := T;
 862
 863       procedure Free is new
 864         Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
 865
 866    begin
 867       if not Single_Lock then
 868          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 869          pragma Assert (Result = 0);
 870       end if;
 871
 872       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 873       pragma Assert (Result = 0);
 874
 875       if T.Known_Tasks_Index /= -1 then
 876          Known_Tasks (T.Known_Tasks_Index) := null;
 877       end if;
 878
 879       Free (Tmp);
 880    end Finalize_TCB;
 881
 882    ---------------
 883    -- Exit_Task --
 884    ---------------
 885
 886    procedure Exit_Task is
 887    begin
 888       pthread_exit (System.Null_Address);
 889    end Exit_Task;
 890
 891    ----------------
 892    -- Abort_Task --
 893    ----------------
 894
 895    procedure Abort_Task (T : Task_ID) is
 896       Result : Interfaces.C.int;
 897
 898    begin
 899       Result := pthread_kill (T.Common.LL.Thread,
 900         Signal (System.Interrupt_Management.Abort_Task_Interrupt));
 901       pragma Assert (Result = 0);
 902    end Abort_Task;
 903
 904    ----------------
 905    -- Check_Exit --
 906    ----------------
 907
 908    --  Dummy versions. The only currently working versions is for solaris
 909    --  (native).
 910
 911    function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
 912    begin
 913       return True;
 914    end Check_Exit;
 915
 916    --------------------
 917    -- Check_No_Locks --
 918    --------------------
 919
 920    function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
 921    begin
 922       return True;
 923    end Check_No_Locks;
 924
 925    ----------------------
 926    -- Environment_Task --
 927    ----------------------
 928
 929    function Environment_Task return Task_ID is
 930    begin
 931       return Environment_Task_ID;
 932    end Environment_Task;
 933
 934    --------------
 935    -- Lock_RTS --
 936    --------------
 937
 938    procedure Lock_RTS is
 939    begin
 940       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
 941    end Lock_RTS;
 942
 943    ----------------
 944    -- Unlock_RTS --
 945    ----------------
 946
 947    procedure Unlock_RTS is
 948    begin
 949       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
 950    end Unlock_RTS;
 951
 952    ------------------
 953    -- Suspend_Task --
 954    ------------------
 955
 956    function Suspend_Task
 957      (T           : ST.Task_ID;
 958       Thread_Self : Thread_Id) return Boolean is
 959    begin
 960       return False;
 961    end Suspend_Task;
 962
 963    -----------------
 964    -- Resume_Task --
 965    -----------------
 966
 967    function Resume_Task
 968      (T           : ST.Task_ID;
 969       Thread_Self : Thread_Id) return Boolean is
 970    begin
 971       return False;
 972    end Resume_Task;
 973
 974    ----------------
 975    -- Initialize --
 976    ----------------
 977
 978    procedure Initialize (Environment_Task : Task_ID) is
 979       act       : aliased struct_sigaction;
 980       old_act   : aliased struct_sigaction;
 981       Tmp_Set   : aliased sigset_t;
 982       Result    : Interfaces.C.int;
 983
 984    begin
 985       Environment_Task_ID := Environment_Task;
 986
 987       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
 988       --  Initialize the lock used to synchronize chain of all ATCBs.
 989
 990       Specific.Initialize (Environment_Task);
 991
 992       Enter_Task (Environment_Task);
 993
 994       --  Install the abort-signal handler
 995
 996       act.sa_flags := 0;
 997       act.sa_handler := Abort_Handler'Address;
 998
 999       Result := sigemptyset (Tmp_Set'Access);
1000       pragma Assert (Result = 0);
1001       act.sa_mask := Tmp_Set;
1002
1003       Result :=
1004         sigaction
1005           (Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1006            act'Unchecked_Access,
1007            old_act'Unchecked_Access);
1008       pragma Assert (Result = 0);
1009    end Initialize;
1010
1011 begin
1012    declare
1013       Result : Interfaces.C.int;
1014    begin
1015       --  Mask Environment task for all signals. The original mask of the
1016       --  Environment task will be recovered by Interrupt_Server task
1017       --  during the elaboration of s-interr.adb.
1018
1019       System.Interrupt_Management.Operations.Set_Interrupt_Mask
1020         (System.Interrupt_Management.Operations.All_Tasks_Mask'Access);
1021
1022       --  Prepare the set of signals that should unblocked in all tasks
1023
1024       Result := sigemptyset (Unblocked_Signal_Mask'Access);
1025       pragma Assert (Result = 0);
1026
1027       for J in Interrupt_Management.Interrupt_ID loop
1028          if System.Interrupt_Management.Keep_Unmasked (J) then
1029             Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1030             pragma Assert (Result = 0);
1031          end if;
1032       end loop;
1033    end;
1034
1035    Curpid := getpid;
1036 end System.Task_Primitives.Operations;