gcc/ada/s-taprop-tru64.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) 1992-2008, 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 Tru64 version of this package
  35
  36 --  This package contains all the GNULL primitives that interface directly with
  37 --  the underlying OS.
  38
  39 pragma Polling (Off);
  40 --  Turn off polling, we do not want ATC polling to take place during tasking
  41 --  operations. It causes infinite loops and other problems.
  42
  43 with Ada.Unchecked_Deallocation;
  44
  45 with Interfaces;
  46 with Interfaces.C;
  47
  48 with System.Tasking.Debug;
  49 with System.Interrupt_Management;
  50 with System.OS_Primitives;
  51 with System.Task_Info;
  52
  53 with System.Soft_Links;
  54 --  We use System.Soft_Links instead of System.Tasking.Initialization
  55 --  because the later is a higher level package that we shouldn't depend on.
  56 --  For example when using the restricted run time, it is replaced by
  57 --  System.Tasking.Restricted.Stages.
  58
  59 package body System.Task_Primitives.Operations is
  60
  61    package SSL renames System.Soft_Links;
  62
  63    use System.Tasking.Debug;
  64    use System.Tasking;
  65    use Interfaces.C;
  66    use System.OS_Interface;
  67    use System.Parameters;
  68    use System.OS_Primitives;
  69
  70    ----------------
  71    -- Local Data --
  72    ----------------
  73
  74    --  The followings are logically constants, but need to be initialized
  75    --  at run time.
  76
  77    Single_RTS_Lock : aliased RTS_Lock;
  78    --  This is a lock to allow only one thread of control in the RTS at
  79    --  a time; it is used to execute in mutual exclusion from all other tasks.
  80    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
  81
  82    ATCB_Key : aliased pthread_key_t;
  83    --  Key used to find the Ada Task_Id associated with a thread
  84
  85    Environment_Task_Id : Task_Id;
  86    --  A variable to hold Task_Id for the environment task
  87
  88    Unblocked_Signal_Mask : aliased sigset_t;
  89    --  The set of signals that should unblocked in all tasks
  90
  91    Time_Slice_Val : Integer;
  92    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
  93
  94    Locking_Policy : Character;
  95    pragma Import (C, Locking_Policy, "__gl_locking_policy");
  96
  97    Dispatching_Policy : Character;
  98    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
  99
 100    Curpid : pid_t;
 101
 102    Foreign_Task_Elaborated : aliased Boolean := True;
 103    --  Used to identified fake tasks (i.e., non-Ada Threads)
 104
 105    --------------------
 106    -- Local Packages --
 107    --------------------
 108
 109    package Specific is
 110
 111       procedure Initialize (Environment_Task : Task_Id);
 112       pragma Inline (Initialize);
 113       --  Initialize various data needed by this package
 114
 115       function Is_Valid_Task return Boolean;
 116       pragma Inline (Is_Valid_Task);
 117       --  Does executing thread have a TCB?
 118
 119       procedure Set (Self_Id : Task_Id);
 120       pragma Inline (Set);
 121       --  Set the self id for the current task
 122
 123       function Self return Task_Id;
 124       pragma Inline (Self);
 125       --  Return a pointer to the Ada Task Control Block of the calling task
 126
 127    end Specific;
 128
 129    package body Specific is separate;
 130    --  The body of this package is target specific
 131
 132    ---------------------------------
 133    -- Support for foreign threads --
 134    ---------------------------------
 135
 136    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 137    --  Allocate and initialize a new ATCB for the current Thread
 138
 139    function Register_Foreign_Thread
 140      (Thread : Thread_Id) return Task_Id is separate;
 141
 142    -----------------------
 143    -- Local Subprograms --
 144    -----------------------
 145
 146    procedure Abort_Handler (Sig : Signal);
 147    --  Signal handler used to implement asynchronous abort
 148
 149    function Get_Policy (Prio : System.Any_Priority) return Character;
 150    pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 151    --  Get priority specific dispatching policy
 152
 153    -------------------
 154    -- Abort_Handler --
 155    -------------------
 156
 157    procedure Abort_Handler (Sig : Signal) is
 158       pragma Unreferenced (Sig);
 159
 160       T       : constant Task_Id := Self;
 161       Old_Set : aliased sigset_t;
 162
 163       Result : Interfaces.C.int;
 164       pragma Warnings (Off, Result);
 165
 166    begin
 167       --  It is not safe to raise an exception when using ZCX and the GCC
 168       --  exception handling mechanism.
 169
 170       if ZCX_By_Default and then GCC_ZCX_Support then
 171          return;
 172       end if;
 173
 174       if T.Deferral_Level = 0
 175         and then T.Pending_ATC_Level < T.ATC_Nesting_Level
 176         and then not T.Aborting
 177       then
 178          T.Aborting := True;
 179
 180          --  Make sure signals used for RTS internal purpose are unmasked
 181
 182          Result :=
 183            pthread_sigmask
 184              (SIG_UNBLOCK,
 185               Unblocked_Signal_Mask'Access,
 186               Old_Set'Access);
 187          pragma Assert (Result = 0);
 188
 189          raise Standard'Abort_Signal;
 190       end if;
 191    end Abort_Handler;
 192
 193    ------------------
 194    -- Stack_Guard  --
 195    ------------------
 196
 197    --  The underlying thread system sets a guard page at the bottom of a thread
 198    --  stack, so nothing is needed.
 199
 200    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 201       pragma Unreferenced (T);
 202       pragma Unreferenced (On);
 203    begin
 204       null;
 205    end Stack_Guard;
 206
 207    --------------------
 208    -- Get_Thread_Id  --
 209    --------------------
 210
 211    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 212    begin
 213       return T.Common.LL.Thread;
 214    end Get_Thread_Id;
 215
 216    ----------
 217    -- Self --
 218    ----------
 219
 220    function Self return Task_Id renames Specific.Self;
 221
 222    ---------------------
 223    -- Initialize_Lock --
 224    ---------------------
 225
 226    --  Note: mutexes and cond_variables needed per-task basis are initialized
 227    --  in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
 228    --  as RTS_Lock, Memory_Lock...) used in RTS is initialized before any
 229    --  status change of RTS. Therefore raising Storage_Error in the following
 230    --  routines should be able to be handled safely.
 231
 232    procedure Initialize_Lock
 233      (Prio : System.Any_Priority;
 234       L    : not null access Lock)
 235    is
 236       Attributes : aliased pthread_mutexattr_t;
 237       Result     : Interfaces.C.int;
 238
 239    begin
 240       Result := pthread_mutexattr_init (Attributes'Access);
 241       pragma Assert (Result = 0 or else Result = ENOMEM);
 242
 243       if Result = ENOMEM then
 244          raise Storage_Error;
 245       end if;
 246
 247       if Locking_Policy = 'C' then
 248          L.Ceiling := Interfaces.C.int (Prio);
 249       end if;
 250
 251       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 252       pragma Assert (Result = 0 or else Result = ENOMEM);
 253
 254       if Result = ENOMEM then
 255          Result := pthread_mutexattr_destroy (Attributes'Access);
 256          raise Storage_Error;
 257       end if;
 258
 259       Result := pthread_mutexattr_destroy (Attributes'Access);
 260       pragma Assert (Result = 0);
 261    end Initialize_Lock;
 262
 263    procedure Initialize_Lock
 264      (L     : not null access RTS_Lock;
 265       Level : Lock_Level)
 266    is
 267       pragma Unreferenced (Level);
 268
 269       Attributes : aliased pthread_mutexattr_t;
 270       Result     : Interfaces.C.int;
 271
 272    begin
 273       Result := pthread_mutexattr_init (Attributes'Access);
 274       pragma Assert (Result = 0 or else Result = ENOMEM);
 275
 276       if Result = ENOMEM then
 277          raise Storage_Error;
 278       end if;
 279
 280       Result := pthread_mutex_init (L, Attributes'Access);
 281       pragma Assert (Result = 0 or else Result = ENOMEM);
 282
 283       if Result = ENOMEM then
 284          Result := pthread_mutexattr_destroy (Attributes'Access);
 285          raise Storage_Error;
 286       end if;
 287
 288       Result := pthread_mutexattr_destroy (Attributes'Access);
 289       pragma Assert (Result = 0);
 290    end Initialize_Lock;
 291
 292    -------------------
 293    -- Finalize_Lock --
 294    -------------------
 295
 296    procedure Finalize_Lock (L : not null access Lock) is
 297       Result : Interfaces.C.int;
 298    begin
 299       Result := pthread_mutex_destroy (L.L'Access);
 300       pragma Assert (Result = 0);
 301    end Finalize_Lock;
 302
 303    procedure Finalize_Lock (L : not null access RTS_Lock) is
 304       Result : Interfaces.C.int;
 305    begin
 306       Result := pthread_mutex_destroy (L);
 307       pragma Assert (Result = 0);
 308    end Finalize_Lock;
 309
 310    ----------------
 311    -- Write_Lock --
 312    ----------------
 313
 314    procedure Write_Lock
 315      (L                 : not null access Lock;
 316       Ceiling_Violation : out Boolean)
 317    is
 318       Result         : Interfaces.C.int;
 319       Self_ID        : Task_Id;
 320       All_Tasks_Link : Task_Id;
 321       Current_Prio   : System.Any_Priority;
 322
 323    begin
 324       --  Perform ceiling checks only when this is the locking policy in use
 325
 326       if Locking_Policy = 'C' then
 327          Self_ID := Self;
 328          All_Tasks_Link := Self_ID.Common.All_Tasks_Link;
 329          Current_Prio := Get_Priority (Self_ID);
 330
 331          --  If there is no other task, no need to check priorities
 332
 333          if All_Tasks_Link /= Null_Task
 334            and then L.Ceiling < Interfaces.C.int (Current_Prio)
 335          then
 336             Ceiling_Violation := True;
 337             return;
 338          end if;
 339       end if;
 340
 341       Result := pthread_mutex_lock (L.L'Access);
 342       pragma Assert (Result = 0);
 343
 344       Ceiling_Violation := False;
 345    end Write_Lock;
 346
 347    procedure Write_Lock
 348      (L           : not null access RTS_Lock;
 349       Global_Lock : Boolean := False)
 350    is
 351       Result : Interfaces.C.int;
 352    begin
 353       if not Single_Lock or else Global_Lock then
 354          Result := pthread_mutex_lock (L);
 355          pragma Assert (Result = 0);
 356       end if;
 357    end Write_Lock;
 358
 359    procedure Write_Lock (T : Task_Id) is
 360       Result : Interfaces.C.int;
 361    begin
 362       if not Single_Lock then
 363          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 364          pragma Assert (Result = 0);
 365       end if;
 366    end Write_Lock;
 367
 368    ---------------
 369    -- Read_Lock --
 370    ---------------
 371
 372    procedure Read_Lock
 373      (L                 : not null access Lock;
 374       Ceiling_Violation : out Boolean)
 375    is
 376    begin
 377       Write_Lock (L, Ceiling_Violation);
 378    end Read_Lock;
 379
 380    ------------
 381    -- Unlock --
 382    ------------
 383
 384    procedure Unlock (L : not null access Lock) is
 385       Result : Interfaces.C.int;
 386    begin
 387       Result := pthread_mutex_unlock (L.L'Access);
 388       pragma Assert (Result = 0);
 389    end Unlock;
 390
 391    procedure Unlock
 392      (L           : not null access RTS_Lock;
 393       Global_Lock : Boolean := False)
 394    is
 395       Result : Interfaces.C.int;
 396    begin
 397       if not Single_Lock or else Global_Lock then
 398          Result := pthread_mutex_unlock (L);
 399          pragma Assert (Result = 0);
 400       end if;
 401    end Unlock;
 402
 403    procedure Unlock (T : Task_Id) is
 404       Result : Interfaces.C.int;
 405    begin
 406       if not Single_Lock then
 407          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 408          pragma Assert (Result = 0);
 409       end if;
 410    end Unlock;
 411
 412    -----------------
 413    -- Set_Ceiling --
 414    -----------------
 415
 416    --  Dynamic priority ceilings are not supported by the underlying system
 417
 418    procedure Set_Ceiling
 419      (L    : not null access Lock;
 420       Prio : System.Any_Priority)
 421    is
 422       pragma Unreferenced (L, Prio);
 423    begin
 424       null;
 425    end Set_Ceiling;
 426
 427    -----------
 428    -- Sleep --
 429    -----------
 430
 431    procedure Sleep
 432      (Self_ID : Task_Id;
 433       Reason  : System.Tasking.Task_States)
 434    is
 435       pragma Unreferenced (Reason);
 436
 437       Result : Interfaces.C.int;
 438
 439    begin
 440       if Single_Lock then
 441          Result :=
 442            pthread_cond_wait
 443              (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 444       else
 445          Result :=
 446            pthread_cond_wait
 447              (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 448       end if;
 449
 450       --  EINTR is not considered a failure
 451
 452       pragma Assert (Result = 0 or else Result = EINTR);
 453    end Sleep;
 454
 455    -----------------
 456    -- Timed_Sleep --
 457    -----------------
 458
 459    --  This is for use within the run-time system, so abort is assumed to be
 460    --  already deferred, and the caller should be holding its own ATCB lock.
 461
 462    procedure Timed_Sleep
 463      (Self_ID  : Task_Id;
 464       Time     : Duration;
 465       Mode     : ST.Delay_Modes;
 466       Reason   : System.Tasking.Task_States;
 467       Timedout : out Boolean;
 468       Yielded  : out Boolean)
 469    is
 470       pragma Unreferenced (Reason);
 471
 472       Base_Time  : constant Duration := Monotonic_Clock;
 473       Check_Time : Duration := Base_Time;
 474       Abs_Time   : Duration;
 475       Request    : aliased timespec;
 476       Result     : Interfaces.C.int;
 477
 478    begin
 479       Timedout := True;
 480       Yielded := False;
 481
 482       if Mode = Relative then
 483          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 484       else
 485          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 486       end if;
 487
 488       if Abs_Time > Check_Time then
 489          Request := To_Timespec (Abs_Time);
 490
 491          loop
 492             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 493
 494             if Single_Lock then
 495                Result :=
 496                  pthread_cond_timedwait
 497                    (Self_ID.Common.LL.CV'Access,
 498                     Single_RTS_Lock'Access,
 499                     Request'Access);
 500
 501             else
 502                Result :=
 503                  pthread_cond_timedwait
 504                    (Self_ID.Common.LL.CV'Access,
 505                     Self_ID.Common.LL.L'Access,
 506                     Request'Access);
 507             end if;
 508
 509             Check_Time := Monotonic_Clock;
 510             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 511
 512             if Result = 0 or Result = EINTR then
 513
 514                --  Somebody may have called Wakeup for us
 515
 516                Timedout := False;
 517                exit;
 518             end if;
 519
 520             pragma Assert (Result = ETIMEDOUT);
 521          end loop;
 522       end if;
 523    end Timed_Sleep;
 524
 525    -----------------
 526    -- Timed_Delay --
 527    -----------------
 528
 529    --  This is for use in implementing delay statements, so we assume the
 530    --  caller is abort-deferred but is holding no locks.
 531
 532    procedure Timed_Delay
 533      (Self_ID  : Task_Id;
 534       Time     : Duration;
 535       Mode     : ST.Delay_Modes)
 536    is
 537       Base_Time  : constant Duration := Monotonic_Clock;
 538       Check_Time : Duration := Base_Time;
 539       Abs_Time   : Duration;
 540       Request    : aliased timespec;
 541       Result     : Interfaces.C.int;
 542
 543    begin
 544       if Single_Lock then
 545          Lock_RTS;
 546       end if;
 547
 548       Write_Lock (Self_ID);
 549
 550       if Mode = Relative then
 551          Abs_Time := Time + Check_Time;
 552       else
 553          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 554       end if;
 555
 556       if Abs_Time > Check_Time then
 557          Request := To_Timespec (Abs_Time);
 558          Self_ID.Common.State := Delay_Sleep;
 559
 560          loop
 561             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 562
 563             if Single_Lock then
 564                Result :=
 565                  pthread_cond_timedwait
 566                    (Self_ID.Common.LL.CV'Access,
 567                     Single_RTS_Lock'Access,
 568                     Request'Access);
 569             else
 570                Result :=
 571                  pthread_cond_timedwait
 572                    (Self_ID.Common.LL.CV'Access,
 573                     Self_ID.Common.LL.L'Access,
 574                     Request'Access);
 575             end if;
 576
 577             Check_Time := Monotonic_Clock;
 578             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 579
 580             pragma Assert (Result = 0         or else
 581                            Result = ETIMEDOUT or else
 582                            Result = EINTR);
 583          end loop;
 584
 585          Self_ID.Common.State := Runnable;
 586       end if;
 587
 588       Unlock (Self_ID);
 589
 590       if Single_Lock then
 591          Unlock_RTS;
 592       end if;
 593
 594       Yield;
 595    end Timed_Delay;
 596
 597    ---------------------
 598    -- Monotonic_Clock --
 599    ---------------------
 600
 601    function Monotonic_Clock return Duration is
 602       TS     : aliased timespec;
 603       Result : Interfaces.C.int;
 604    begin
 605       Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 606       pragma Assert (Result = 0);
 607       return To_Duration (TS);
 608    end Monotonic_Clock;
 609
 610    -------------------
 611    -- RT_Resolution --
 612    -------------------
 613
 614    function RT_Resolution return Duration is
 615    begin
 616       --  Returned value must be an integral multiple of Duration'Small (1 ns)
 617       --  The following is the best approximation of 1/1024. The clock on the
 618       --  DEC Alpha ticks at 1024 Hz.
 619
 620       return 0.000_976_563;
 621    end RT_Resolution;
 622
 623    ------------
 624    -- Wakeup --
 625    ------------
 626
 627    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 628       pragma Unreferenced (Reason);
 629       Result : Interfaces.C.int;
 630    begin
 631       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 632       pragma Assert (Result = 0);
 633    end Wakeup;
 634
 635    -----------
 636    -- Yield --
 637    -----------
 638
 639    procedure Yield (Do_Yield : Boolean := True) is
 640       Result : Interfaces.C.int;
 641       pragma Unreferenced (Result);
 642    begin
 643       if Do_Yield then
 644          Result := sched_yield;
 645       end if;
 646    end Yield;
 647
 648    ------------------
 649    -- Set_Priority --
 650    ------------------
 651
 652    procedure Set_Priority
 653      (T                   : Task_Id;
 654       Prio                : System.Any_Priority;
 655       Loss_Of_Inheritance : Boolean := False)
 656    is
 657       pragma Unreferenced (Loss_Of_Inheritance);
 658
 659       Result : Interfaces.C.int;
 660       Param  : aliased struct_sched_param;
 661
 662       Priority_Specific_Policy : constant Character := Get_Policy (Prio);
 663       --  Upper case first character of the policy name corresponding to the
 664       --  task as set by a Priority_Specific_Dispatching pragma.
 665
 666    begin
 667       T.Common.Current_Priority := Prio;
 668       Param.sched_priority  := Interfaces.C.int (Underlying_Priorities (Prio));
 669
 670       if Dispatching_Policy = 'R'
 671         or else Priority_Specific_Policy = 'R'
 672         or else Time_Slice_Val > 0
 673       then
 674          Result :=
 675            pthread_setschedparam
 676              (T.Common.LL.Thread, SCHED_RR, Param'Access);
 677
 678       elsif Dispatching_Policy = 'F'
 679         or else Priority_Specific_Policy = 'F'
 680         or else Time_Slice_Val = 0
 681       then
 682          Result :=
 683            pthread_setschedparam
 684              (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 685
 686       else
 687          Result :=
 688            pthread_setschedparam
 689              (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 690       end if;
 691
 692       pragma Assert (Result = 0);
 693    end Set_Priority;
 694
 695    ------------------
 696    -- Get_Priority --
 697    ------------------
 698
 699    function Get_Priority (T : Task_Id) return System.Any_Priority is
 700    begin
 701       return T.Common.Current_Priority;
 702    end Get_Priority;
 703
 704    ----------------
 705    -- Enter_Task --
 706    ----------------
 707
 708    procedure Enter_Task (Self_ID : Task_Id) is
 709    begin
 710       Hide_Unhide_Yellow_Zone (Hide => True);
 711       Self_ID.Common.LL.Thread := pthread_self;
 712       Specific.Set (Self_ID);
 713
 714       Lock_RTS;
 715
 716       for J in Known_Tasks'Range loop
 717          if Known_Tasks (J) = null then
 718             Known_Tasks (J) := Self_ID;
 719             Self_ID.Known_Tasks_Index := J;
 720             exit;
 721          end if;
 722       end loop;
 723
 724       Unlock_RTS;
 725    end Enter_Task;
 726
 727    --------------
 728    -- New_ATCB --
 729    --------------
 730
 731    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 732    begin
 733       return new Ada_Task_Control_Block (Entry_Num);
 734    end New_ATCB;
 735
 736    -------------------
 737    -- Is_Valid_Task --
 738    -------------------
 739
 740    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 741
 742    -----------------------------
 743    -- Register_Foreign_Thread --
 744    -----------------------------
 745
 746    function Register_Foreign_Thread return Task_Id is
 747    begin
 748       if Is_Valid_Task then
 749          return Self;
 750       else
 751          return Register_Foreign_Thread (pthread_self);
 752       end if;
 753    end Register_Foreign_Thread;
 754
 755    --------------------
 756    -- Initialize_TCB --
 757    --------------------
 758
 759    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 760       Mutex_Attr : aliased pthread_mutexattr_t;
 761       Result     : Interfaces.C.int;
 762       Cond_Attr  : aliased pthread_condattr_t;
 763
 764    begin
 765       if not Single_Lock then
 766          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 767          pragma Assert (Result = 0 or else Result = ENOMEM);
 768
 769          if Result = 0 then
 770             Result :=
 771               pthread_mutex_init
 772                 (Self_ID.Common.LL.L'Access, Mutex_Attr'Access);
 773             pragma Assert (Result = 0 or else Result = ENOMEM);
 774          end if;
 775
 776          if Result /= 0 then
 777             Succeeded := False;
 778             return;
 779          end if;
 780
 781          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 782          pragma Assert (Result = 0);
 783       end if;
 784
 785       Result := pthread_condattr_init (Cond_Attr'Access);
 786       pragma Assert (Result = 0 or else Result = ENOMEM);
 787
 788       if Result = 0 then
 789          Result :=
 790            pthread_cond_init
 791              (Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
 792          pragma Assert (Result = 0 or else Result = ENOMEM);
 793       end if;
 794
 795       if Result = 0 then
 796          Succeeded := True;
 797       else
 798          if not Single_Lock then
 799             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 800             pragma Assert (Result = 0);
 801          end if;
 802
 803          Succeeded := False;
 804       end if;
 805
 806       Result := pthread_condattr_destroy (Cond_Attr'Access);
 807       pragma Assert (Result = 0);
 808    end Initialize_TCB;
 809
 810    -----------------
 811    -- Create_Task --
 812    -----------------
 813
 814    procedure Create_Task
 815      (T          : Task_Id;
 816       Wrapper    : System.Address;
 817       Stack_Size : System.Parameters.Size_Type;
 818       Priority   : System.Any_Priority;
 819       Succeeded  : out Boolean)
 820    is
 821       Attributes          : aliased pthread_attr_t;
 822       Adjusted_Stack_Size : Interfaces.C.size_t;
 823       Result              : Interfaces.C.int;
 824       Param               : aliased System.OS_Interface.struct_sched_param;
 825
 826       Priority_Specific_Policy : constant Character := Get_Policy (Priority);
 827       --  Upper case first character of the policy name corresponding to the
 828       --  task as set by a Priority_Specific_Dispatching pragma.
 829
 830       use System.Task_Info;
 831
 832    begin
 833       --  Account for the Yellow Zone (2 pages) and the guard page right above.
 834       --  See Hide_Unhide_Yellow_Zone for the rationale.
 835
 836       Adjusted_Stack_Size :=
 837         Interfaces.C.size_t (Stack_Size) + 3 * Get_Page_Size;
 838
 839       Result := pthread_attr_init (Attributes'Access);
 840       pragma Assert (Result = 0 or else Result = ENOMEM);
 841
 842       if Result /= 0 then
 843          Succeeded := False;
 844          return;
 845       end if;
 846
 847       Result :=
 848         pthread_attr_setdetachstate
 849           (Attributes'Access, PTHREAD_CREATE_DETACHED);
 850       pragma Assert (Result = 0);
 851
 852       Result :=
 853         pthread_attr_setstacksize
 854           (Attributes'Access, Adjusted_Stack_Size);
 855       pragma Assert (Result = 0);
 856
 857       Param.sched_priority :=
 858         Interfaces.C.int (Underlying_Priorities (Priority));
 859       Result :=
 860         pthread_attr_setschedparam
 861           (Attributes'Access, Param'Access);
 862       pragma Assert (Result = 0);
 863
 864       if Dispatching_Policy = 'R'
 865         or else Priority_Specific_Policy = 'R'
 866         or else Time_Slice_Val > 0
 867       then
 868          Result :=
 869            pthread_attr_setschedpolicy
 870              (Attributes'Access, System.OS_Interface.SCHED_RR);
 871
 872       elsif Dispatching_Policy = 'F'
 873         or else Priority_Specific_Policy = 'F'
 874         or else Time_Slice_Val = 0
 875       then
 876          Result :=
 877            pthread_attr_setschedpolicy
 878              (Attributes'Access, System.OS_Interface.SCHED_FIFO);
 879
 880       else
 881          Result :=
 882            pthread_attr_setschedpolicy
 883              (Attributes'Access, System.OS_Interface.SCHED_OTHER);
 884       end if;
 885
 886       pragma Assert (Result = 0);
 887
 888       --  Set the scheduling parameters explicitly, since this is the only way
 889       --  to force the OS to take e.g. the sched policy and scope attributes
 890       --  into account.
 891
 892       Result :=
 893         pthread_attr_setinheritsched
 894           (Attributes'Access, PTHREAD_EXPLICIT_SCHED);
 895       pragma Assert (Result = 0);
 896
 897       T.Common.Current_Priority := Priority;
 898
 899       if T.Common.Task_Info /= null then
 900          case T.Common.Task_Info.Contention_Scope is
 901             when System.Task_Info.Process_Scope =>
 902                Result :=
 903                  pthread_attr_setscope
 904                    (Attributes'Access, PTHREAD_SCOPE_PROCESS);
 905
 906             when System.Task_Info.System_Scope =>
 907                Result :=
 908                  pthread_attr_setscope
 909                    (Attributes'Access, PTHREAD_SCOPE_SYSTEM);
 910
 911             when System.Task_Info.Default_Scope =>
 912                Result := 0;
 913          end case;
 914
 915          pragma Assert (Result = 0);
 916       end if;
 917
 918       --  Since the initial signal mask of a thread is inherited from the
 919       --  creator, and the Environment task has all its signals masked, we
 920       --  do not need to manipulate caller's signal mask at this point.
 921       --  All tasks in RTS will have All_Tasks_Mask initially.
 922
 923       Result :=
 924         pthread_create
 925           (T.Common.LL.Thread'Access,
 926            Attributes'Access,
 927            Thread_Body_Access (Wrapper),
 928            To_Address (T));
 929       pragma Assert (Result = 0 or else Result = EAGAIN);
 930
 931       Succeeded := Result = 0;
 932
 933       Result := pthread_attr_destroy (Attributes'Access);
 934       pragma Assert (Result = 0);
 935
 936       if Succeeded and then T.Common.Task_Info /= null then
 937
 938          --  ??? We're using a process-wide function to implement a task
 939          --  specific characteristic.
 940
 941          if T.Common.Task_Info.Bind_To_Cpu_Number = 0 then
 942             Result := bind_to_cpu (Curpid, 0);
 943
 944          elsif T.Common.Task_Info.Bind_To_Cpu_Number > 0 then
 945             Result :=
 946               bind_to_cpu
 947                 (Curpid,
 948                  Interfaces.C.unsigned_long (
 949                    Interfaces.Shift_Left
 950                      (Interfaces.Unsigned_64'(1),
 951                       T.Common.Task_Info.Bind_To_Cpu_Number - 1)));
 952             pragma Assert (Result = 0);
 953          end if;
 954       end if;
 955    end Create_Task;
 956
 957    ------------------
 958    -- Finalize_TCB --
 959    ------------------
 960
 961    procedure Finalize_TCB (T : Task_Id) is
 962       Result  : Interfaces.C.int;
 963       Tmp     : Task_Id := T;
 964       Is_Self : constant Boolean := T = Self;
 965
 966       procedure Free is new
 967         Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 968
 969    begin
 970       if not Single_Lock then
 971          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 972          pragma Assert (Result = 0);
 973       end if;
 974
 975       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 976       pragma Assert (Result = 0);
 977
 978       if T.Known_Tasks_Index /= -1 then
 979          Known_Tasks (T.Known_Tasks_Index) := null;
 980       end if;
 981
 982       Free (Tmp);
 983
 984       if Is_Self then
 985          Specific.Set (null);
 986       end if;
 987    end Finalize_TCB;
 988
 989    ---------------
 990    -- Exit_Task --
 991    ---------------
 992
 993    procedure Exit_Task is
 994    begin
 995       Specific.Set (null);
 996       Hide_Unhide_Yellow_Zone (Hide => False);
 997    end Exit_Task;
 998
 999    ----------------
1000    -- Abort_Task --
1001    ----------------
1002
1003    procedure Abort_Task (T : Task_Id) is
1004       Result : Interfaces.C.int;
1005    begin
1006       Result := pthread_kill (T.Common.LL.Thread,
1007         Signal (System.Interrupt_Management.Abort_Task_Interrupt));
1008       pragma Assert (Result = 0);
1009    end Abort_Task;
1010
1011    ----------------
1012    -- Initialize --
1013    ----------------
1014
1015    procedure Initialize (S : in out Suspension_Object) is
1016       Mutex_Attr : aliased pthread_mutexattr_t;
1017       Cond_Attr  : aliased pthread_condattr_t;
1018       Result     : Interfaces.C.int;
1019
1020    begin
1021       --  Initialize internal state (always to False (RM D.10(6)))
1022
1023       S.State := False;
1024       S.Waiting := False;
1025
1026       --  Initialize internal mutex
1027
1028       Result := pthread_mutexattr_init (Mutex_Attr'Access);
1029       pragma Assert (Result = 0 or else Result = ENOMEM);
1030
1031       if Result = ENOMEM then
1032          raise Storage_Error;
1033       end if;
1034
1035       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
1036       pragma Assert (Result = 0 or else Result = ENOMEM);
1037
1038       if Result = ENOMEM then
1039          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
1040          raise Storage_Error;
1041       end if;
1042
1043       Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
1044       pragma Assert (Result = 0);
1045
1046       --  Initialize internal condition variable
1047
1048       Result := pthread_condattr_init (Cond_Attr'Access);
1049       pragma Assert (Result = 0 or else Result = ENOMEM);
1050
1051       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
1052
1053       pragma Assert (Result = 0 or else Result = ENOMEM);
1054
1055       if Result /= 0 then
1056          Result := pthread_mutex_destroy (S.L'Access);
1057          pragma Assert (Result = 0);
1058
1059          if Result = ENOMEM then
1060             raise Storage_Error;
1061          end if;
1062       end if;
1063    end Initialize;
1064
1065    --------------
1066    -- Finalize --
1067    --------------
1068
1069    procedure Finalize (S : in out Suspension_Object) is
1070       Result  : Interfaces.C.int;
1071
1072    begin
1073       --  Destroy internal mutex
1074
1075       Result := pthread_mutex_destroy (S.L'Access);
1076       pragma Assert (Result = 0);
1077
1078       --  Destroy internal condition variable
1079
1080       Result := pthread_cond_destroy (S.CV'Access);
1081       pragma Assert (Result = 0);
1082    end Finalize;
1083
1084    -------------------
1085    -- Current_State --
1086    -------------------
1087
1088    function Current_State (S : Suspension_Object) return Boolean is
1089    begin
1090       --  We do not want to use lock on this read operation. State is marked
1091       --  as Atomic so that we ensure that the value retrieved is correct.
1092
1093       return S.State;
1094    end Current_State;
1095
1096    ---------------
1097    -- Set_False --
1098    ---------------
1099
1100    procedure Set_False (S : in out Suspension_Object) is
1101       Result  : Interfaces.C.int;
1102
1103    begin
1104       SSL.Abort_Defer.all;
1105
1106       Result := pthread_mutex_lock (S.L'Access);
1107       pragma Assert (Result = 0);
1108
1109       S.State := False;
1110
1111       Result := pthread_mutex_unlock (S.L'Access);
1112       pragma Assert (Result = 0);
1113
1114       SSL.Abort_Undefer.all;
1115    end Set_False;
1116
1117    --------------
1118    -- Set_True --
1119    --------------
1120
1121    procedure Set_True (S : in out Suspension_Object) is
1122       Result : Interfaces.C.int;
1123
1124    begin
1125       SSL.Abort_Defer.all;
1126
1127       Result := pthread_mutex_lock (S.L'Access);
1128       pragma Assert (Result = 0);
1129
1130       --  If there is already a task waiting on this suspension object then we
1131       --  resume it, leaving the state of the suspension object to False, as
1132       --  specified in (RM D.10(9)). Otherwise, leave the state set to True.
1133
1134       if S.Waiting then
1135          S.Waiting := False;
1136          S.State := False;
1137
1138          Result := pthread_cond_signal (S.CV'Access);
1139          pragma Assert (Result = 0);
1140
1141       else
1142          S.State := True;
1143       end if;
1144
1145       Result := pthread_mutex_unlock (S.L'Access);
1146       pragma Assert (Result = 0);
1147
1148       SSL.Abort_Undefer.all;
1149    end Set_True;
1150
1151    ------------------------
1152    -- Suspend_Until_True --
1153    ------------------------
1154
1155    procedure Suspend_Until_True (S : in out Suspension_Object) is
1156       Result : Interfaces.C.int;
1157
1158    begin
1159       SSL.Abort_Defer.all;
1160
1161       Result := pthread_mutex_lock (S.L'Access);
1162       pragma Assert (Result = 0);
1163
1164       if S.Waiting then
1165
1166          --  Program_Error must be raised upon calling Suspend_Until_True
1167          --  if another task is already waiting on that suspension object
1168          --  (AM D.10(10)).
1169
1170          Result := pthread_mutex_unlock (S.L'Access);
1171          pragma Assert (Result = 0);
1172
1173          SSL.Abort_Undefer.all;
1174
1175          raise Program_Error;
1176
1177       else
1178          --  Suspend the task if the state is False. Otherwise, the task
1179          --  continues its execution, and the state of the suspension object
1180          --  is set to False (RM D.10(9)).
1181
1182          if S.State then
1183             S.State := False;
1184          else
1185             S.Waiting := True;
1186             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1187          end if;
1188
1189          Result := pthread_mutex_unlock (S.L'Access);
1190          pragma Assert (Result = 0);
1191
1192          SSL.Abort_Undefer.all;
1193       end if;
1194    end Suspend_Until_True;
1195
1196    ----------------
1197    -- Check_Exit --
1198    ----------------
1199
1200    --  Dummy version
1201
1202    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1203       pragma Unreferenced (Self_ID);
1204    begin
1205       return True;
1206    end Check_Exit;
1207
1208    --------------------
1209    -- Check_No_Locks --
1210    --------------------
1211
1212    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1213       pragma Unreferenced (Self_ID);
1214    begin
1215       return True;
1216    end Check_No_Locks;
1217
1218    ----------------------
1219    -- Environment_Task --
1220    ----------------------
1221
1222    function Environment_Task return Task_Id is
1223    begin
1224       return Environment_Task_Id;
1225    end Environment_Task;
1226
1227    --------------
1228    -- Lock_RTS --
1229    --------------
1230
1231    procedure Lock_RTS is
1232    begin
1233       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1234    end Lock_RTS;
1235
1236    ----------------
1237    -- Unlock_RTS --
1238    ----------------
1239
1240    procedure Unlock_RTS is
1241    begin
1242       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1243    end Unlock_RTS;
1244
1245    ------------------
1246    -- Suspend_Task --
1247    ------------------
1248
1249    function Suspend_Task
1250      (T           : ST.Task_Id;
1251       Thread_Self : Thread_Id) return Boolean
1252    is
1253       pragma Unreferenced (T, Thread_Self);
1254    begin
1255       return False;
1256    end Suspend_Task;
1257
1258    -----------------
1259    -- Resume_Task --
1260    -----------------
1261
1262    function Resume_Task
1263      (T           : ST.Task_Id;
1264       Thread_Self : Thread_Id) return Boolean
1265    is
1266       pragma Unreferenced (T, Thread_Self);
1267    begin
1268       return False;
1269    end Resume_Task;
1270
1271    --------------------
1272    -- Stop_All_Tasks --
1273    --------------------
1274
1275    procedure Stop_All_Tasks is
1276    begin
1277       null;
1278    end Stop_All_Tasks;
1279
1280    ---------------
1281    -- Stop_Task --
1282    ---------------
1283
1284    function Stop_Task (T : ST.Task_Id) return Boolean is
1285       pragma Unreferenced (T);
1286    begin
1287       return False;
1288    end Stop_Task;
1289
1290    -------------------
1291    -- Continue_Task --
1292    -------------------
1293
1294    function Continue_Task (T : ST.Task_Id) return Boolean is
1295       pragma Unreferenced (T);
1296    begin
1297       return False;
1298    end Continue_Task;
1299
1300    ----------------
1301    -- Initialize --
1302    ----------------
1303
1304    procedure Initialize (Environment_Task : Task_Id) is
1305       act     : aliased struct_sigaction;
1306       old_act : aliased struct_sigaction;
1307       Tmp_Set : aliased sigset_t;
1308       Result  : Interfaces.C.int;
1309
1310       function State
1311         (Int : System.Interrupt_Management.Interrupt_ID) return Character;
1312       pragma Import (C, State, "__gnat_get_interrupt_state");
1313       --  Get interrupt state. Defined in a-init.c. The input argument is
1314       --  the interrupt number, and the result is one of the following:
1315
1316       Default : constant Character := 's';
1317       --    'n'   this interrupt not set by any Interrupt_State pragma
1318       --    'u'   Interrupt_State pragma set state to User
1319       --    'r'   Interrupt_State pragma set state to Runtime
1320       --    's'   Interrupt_State pragma set state to System (use "default"
1321       --           system handler)
1322
1323    begin
1324       Environment_Task_Id := Environment_Task;
1325
1326       Interrupt_Management.Initialize;
1327
1328       --  Prepare the set of signals that should unblocked in all tasks
1329
1330       Result := sigemptyset (Unblocked_Signal_Mask'Access);
1331       pragma Assert (Result = 0);
1332
1333       for J in Interrupt_Management.Interrupt_ID loop
1334          if System.Interrupt_Management.Keep_Unmasked (J) then
1335             Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1336             pragma Assert (Result = 0);
1337          end if;
1338       end loop;
1339
1340       Curpid := getpid;
1341
1342       --  Initialize the lock used to synchronize chain of all ATCBs
1343
1344       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1345
1346       Specific.Initialize (Environment_Task);
1347
1348       Enter_Task (Environment_Task);
1349
1350       --  Install the abort-signal handler
1351
1352       if State
1353           (System.Interrupt_Management.Abort_Task_Interrupt) /= Default
1354       then
1355          act.sa_flags := 0;
1356          act.sa_handler := Abort_Handler'Address;
1357
1358          Result := sigemptyset (Tmp_Set'Access);
1359          pragma Assert (Result = 0);
1360          act.sa_mask := Tmp_Set;
1361
1362          Result :=
1363            sigaction
1364              (Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1365               act'Unchecked_Access,
1366               old_act'Unchecked_Access);
1367          pragma Assert (Result = 0);
1368       end if;
1369    end Initialize;
1370
1371 end System.Task_Primitives.Operations;