gcc/ada/s-taprop-vms.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 OpenVMS/Alpha 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_Conversion;
  44 with Ada.Unchecked_Deallocation;
  45
  46 with Interfaces.C;
  47
  48 with System.Tasking.Debug;
  49 with System.OS_Primitives;
  50 with System.Soft_Links;
  51 with System.Aux_DEC;
  52
  53 package body System.Task_Primitives.Operations is
  54
  55    use System.Tasking.Debug;
  56    use System.Tasking;
  57    use Interfaces.C;
  58    use System.OS_Interface;
  59    use System.Parameters;
  60    use System.OS_Primitives;
  61    use type System.OS_Primitives.OS_Time;
  62
  63    package SSL renames System.Soft_Links;
  64
  65    ----------------
  66    -- Local Data --
  67    ----------------
  68
  69    --  The followings are logically constants, but need to be initialized
  70    --  at run time.
  71
  72    Single_RTS_Lock : aliased RTS_Lock;
  73    --  This is a lock to allow only one thread of control in the RTS at
  74    --  a time; it is used to execute in mutual exclusion from all other tasks.
  75    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
  76
  77    ATCB_Key : aliased pthread_key_t;
  78    --  Key used to find the Ada Task_Id associated with a thread
  79
  80    Environment_Task_Id : Task_Id;
  81    --  A variable to hold Task_Id for the environment task
  82
  83    Time_Slice_Val : Integer;
  84    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
  85
  86    Dispatching_Policy : Character;
  87    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
  88
  89    Foreign_Task_Elaborated : aliased Boolean := True;
  90    --  Used to identified fake tasks (i.e., non-Ada Threads)
  91
  92    --------------------
  93    -- Local Packages --
  94    --------------------
  95
  96    package Specific is
  97
  98       procedure Initialize (Environment_Task : Task_Id);
  99       pragma Inline (Initialize);
 100       --  Initialize various data needed by this package
 101
 102       function Is_Valid_Task return Boolean;
 103       pragma Inline (Is_Valid_Task);
 104       --  Does executing thread have a TCB?
 105
 106       procedure Set (Self_Id : Task_Id);
 107       pragma Inline (Set);
 108       --  Set the self id for the current task
 109
 110       function Self return Task_Id;
 111       pragma Inline (Self);
 112       --  Return a pointer to the Ada Task Control Block of the calling task
 113
 114    end Specific;
 115
 116    package body Specific is separate;
 117    --  The body of this package is target specific
 118
 119    ---------------------------------
 120    -- Support for foreign threads --
 121    ---------------------------------
 122
 123    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 124    --  Allocate and Initialize a new ATCB for the current Thread
 125
 126    function Register_Foreign_Thread
 127      (Thread : Thread_Id) return Task_Id is separate;
 128
 129    -----------------------
 130    -- Local Subprograms --
 131    -----------------------
 132
 133    function To_Task_Id is
 134      new Ada.Unchecked_Conversion
 135        (System.Task_Primitives.Task_Address, Task_Id);
 136
 137    function To_Address is
 138      new Ada.Unchecked_Conversion
 139        (Task_Id, System.Task_Primitives.Task_Address);
 140
 141    function Get_Exc_Stack_Addr return Address;
 142    --  Replace System.Soft_Links.Get_Exc_Stack_Addr_NT
 143
 144    procedure Timer_Sleep_AST (ID : Address);
 145    pragma Convention (C, Timer_Sleep_AST);
 146    --  Signal the condition variable when AST fires
 147
 148    procedure Timer_Sleep_AST (ID : Address) is
 149       Result : Interfaces.C.int;
 150       pragma Warnings (Off, Result);
 151       Self_ID : constant Task_Id := To_Task_Id (ID);
 152    begin
 153       Self_ID.Common.LL.AST_Pending := False;
 154       Result := pthread_cond_signal_int_np (Self_ID.Common.LL.CV'Access);
 155       pragma Assert (Result = 0);
 156    end Timer_Sleep_AST;
 157
 158    -----------------
 159    -- Stack_Guard --
 160    -----------------
 161
 162    --  The underlying thread system sets a guard page at the bottom of a thread
 163    --  stack, so nothing is needed.
 164    --  ??? Check the comment above
 165
 166    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 167       pragma Unreferenced (T);
 168       pragma Unreferenced (On);
 169    begin
 170       null;
 171    end Stack_Guard;
 172
 173    --------------------
 174    -- Get_Thread_Id  --
 175    --------------------
 176
 177    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 178    begin
 179       return T.Common.LL.Thread;
 180    end Get_Thread_Id;
 181
 182    ----------
 183    -- Self --
 184    ----------
 185
 186    function Self return Task_Id renames Specific.Self;
 187
 188    ---------------------
 189    -- Initialize_Lock --
 190    ---------------------
 191
 192    --  Note: mutexes and cond_variables needed per-task basis are initialized
 193    --  in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
 194    --  as RTS_Lock, Memory_Lock...) used in RTS is initialized before any
 195    --  status change of RTS. Therefore raising Storage_Error in the following
 196    --  routines should be able to be handled safely.
 197
 198    procedure Initialize_Lock
 199      (Prio : System.Any_Priority;
 200       L    : not null access Lock)
 201    is
 202       Attributes : aliased pthread_mutexattr_t;
 203       Result     : Interfaces.C.int;
 204
 205    begin
 206       Result := pthread_mutexattr_init (Attributes'Access);
 207       pragma Assert (Result = 0 or else Result = ENOMEM);
 208
 209       if Result = ENOMEM then
 210          raise Storage_Error;
 211       end if;
 212
 213       L.Prio_Save := 0;
 214       L.Prio := Interfaces.C.int (Prio);
 215
 216       Result := pthread_mutex_init (L.L'Access, Attributes'Access);
 217       pragma Assert (Result = 0 or else Result = ENOMEM);
 218
 219       if Result = ENOMEM then
 220          raise Storage_Error;
 221       end if;
 222
 223       Result := pthread_mutexattr_destroy (Attributes'Access);
 224       pragma Assert (Result = 0);
 225    end Initialize_Lock;
 226
 227    procedure Initialize_Lock
 228      (L     : not null access RTS_Lock;
 229       Level : Lock_Level)
 230    is
 231       pragma Unreferenced (Level);
 232
 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 --      Don't use, see comment in s-osinte.ads about ERRORCHECK mutexes???
 245 --      Result := pthread_mutexattr_settype_np
 246 --        (Attributes'Access, PTHREAD_MUTEX_ERRORCHECK_NP);
 247 --      pragma Assert (Result = 0);
 248
 249 --      Result := pthread_mutexattr_setprotocol
 250 --        (Attributes'Access, PTHREAD_PRIO_PROTECT);
 251 --      pragma Assert (Result = 0);
 252
 253 --      Result := pthread_mutexattr_setprioceiling
 254 --         (Attributes'Access, Interfaces.C.int (System.Any_Priority'Last));
 255 --      pragma Assert (Result = 0);
 256
 257       Result := pthread_mutex_init (L, Attributes'Access);
 258
 259       pragma Assert (Result = 0 or else Result = ENOMEM);
 260
 261       if Result = ENOMEM then
 262          raise Storage_Error;
 263       end if;
 264
 265       Result := pthread_mutexattr_destroy (Attributes'Access);
 266       pragma Assert (Result = 0);
 267    end Initialize_Lock;
 268
 269    -------------------
 270    -- Finalize_Lock --
 271    -------------------
 272
 273    procedure Finalize_Lock (L : not null access Lock) is
 274       Result : Interfaces.C.int;
 275    begin
 276       Result := pthread_mutex_destroy (L.L'Access);
 277       pragma Assert (Result = 0);
 278    end Finalize_Lock;
 279
 280    procedure Finalize_Lock (L : not null access RTS_Lock) is
 281       Result : Interfaces.C.int;
 282    begin
 283       Result := pthread_mutex_destroy (L);
 284       pragma Assert (Result = 0);
 285    end Finalize_Lock;
 286
 287    ----------------
 288    -- Write_Lock --
 289    ----------------
 290
 291    procedure Write_Lock
 292      (L                 : not null access Lock;
 293       Ceiling_Violation : out Boolean)
 294    is
 295       Self_ID        : constant Task_Id := Self;
 296       All_Tasks_Link : constant Task_Id := Self.Common.All_Tasks_Link;
 297       Current_Prio   : System.Any_Priority;
 298       Result         : Interfaces.C.int;
 299
 300    begin
 301       Current_Prio := Get_Priority (Self_ID);
 302
 303       --  If there is no other tasks, no need to check priorities
 304
 305       if All_Tasks_Link /= Null_Task
 306         and then L.Prio < Interfaces.C.int (Current_Prio)
 307       then
 308          Ceiling_Violation := True;
 309          return;
 310       end if;
 311
 312       Result := pthread_mutex_lock (L.L'Access);
 313       pragma Assert (Result = 0);
 314
 315       Ceiling_Violation := False;
 316 --  Why is this commented out ???
 317 --      L.Prio_Save := Interfaces.C.int (Current_Prio);
 318 --      Set_Priority (Self_ID, System.Any_Priority (L.Prio));
 319    end Write_Lock;
 320
 321    procedure Write_Lock
 322      (L           : not null access RTS_Lock;
 323       Global_Lock : Boolean := False)
 324    is
 325       Result : Interfaces.C.int;
 326    begin
 327       if not Single_Lock or else Global_Lock then
 328          Result := pthread_mutex_lock (L);
 329          pragma Assert (Result = 0);
 330       end if;
 331    end Write_Lock;
 332
 333    procedure Write_Lock (T : Task_Id) is
 334       Result : Interfaces.C.int;
 335    begin
 336       if not Single_Lock then
 337          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 338          pragma Assert (Result = 0);
 339       end if;
 340    end Write_Lock;
 341
 342    ---------------
 343    -- Read_Lock --
 344    ---------------
 345
 346    procedure Read_Lock
 347      (L                 : not null access Lock;
 348       Ceiling_Violation : out Boolean)
 349    is
 350    begin
 351       Write_Lock (L, Ceiling_Violation);
 352    end Read_Lock;
 353
 354    ------------
 355    -- Unlock --
 356    ------------
 357
 358    procedure Unlock (L : not null access Lock) is
 359       Result : Interfaces.C.int;
 360    begin
 361       Result := pthread_mutex_unlock (L.L'Access);
 362       pragma Assert (Result = 0);
 363    end Unlock;
 364
 365    procedure Unlock
 366      (L           : not null access RTS_Lock;
 367       Global_Lock : Boolean := False)
 368    is
 369       Result : Interfaces.C.int;
 370    begin
 371       if not Single_Lock or else Global_Lock then
 372          Result := pthread_mutex_unlock (L);
 373          pragma Assert (Result = 0);
 374       end if;
 375    end Unlock;
 376
 377    procedure Unlock (T : Task_Id) is
 378       Result : Interfaces.C.int;
 379    begin
 380       if not Single_Lock then
 381          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 382          pragma Assert (Result = 0);
 383       end if;
 384    end Unlock;
 385
 386    -----------------
 387    -- Set_Ceiling --
 388    -----------------
 389
 390    --  Dynamic priority ceilings are not supported by the underlying system
 391
 392    procedure Set_Ceiling
 393      (L    : not null access Lock;
 394       Prio : System.Any_Priority)
 395    is
 396       pragma Unreferenced (L, Prio);
 397    begin
 398       null;
 399    end Set_Ceiling;
 400
 401    -----------
 402    -- Sleep --
 403    -----------
 404
 405    procedure Sleep
 406      (Self_ID : Task_Id;
 407       Reason  : System.Tasking.Task_States)
 408    is
 409       pragma Unreferenced (Reason);
 410       Result : Interfaces.C.int;
 411
 412    begin
 413       if Single_Lock then
 414          Result :=
 415            pthread_cond_wait
 416              (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 417       else
 418          Result :=
 419            pthread_cond_wait
 420              (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 421       end if;
 422
 423       --  EINTR is not considered a failure
 424
 425       pragma Assert (Result = 0 or else Result = EINTR);
 426
 427       if Self_ID.Deferral_Level = 0
 428         and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 429       then
 430          Unlock (Self_ID);
 431          raise Standard'Abort_Signal;
 432       end if;
 433    end Sleep;
 434
 435    -----------------
 436    -- Timed_Sleep --
 437    -----------------
 438
 439    procedure Timed_Sleep
 440      (Self_ID  : Task_Id;
 441       Time     : Duration;
 442       Mode     : ST.Delay_Modes;
 443       Reason   : System.Tasking.Task_States;
 444       Timedout : out Boolean;
 445       Yielded  : out Boolean)
 446    is
 447       pragma Unreferenced (Reason);
 448
 449       Sleep_Time : OS_Time;
 450       Result     : Interfaces.C.int;
 451       Status     : Cond_Value_Type;
 452
 453       --  The body below requires more comments ???
 454
 455    begin
 456       Timedout := False;
 457       Yielded := False;
 458
 459       Sleep_Time := To_OS_Time (Time, Mode);
 460
 461       if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
 462          return;
 463       end if;
 464
 465       Self_ID.Common.LL.AST_Pending := True;
 466
 467       Sys_Setimr
 468        (Status, 0, Sleep_Time,
 469         Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
 470
 471       if (Status and 1) /= 1 then
 472          raise Storage_Error;
 473       end if;
 474
 475       if Single_Lock then
 476          Result :=
 477            pthread_cond_wait
 478              (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 479          pragma Assert (Result = 0);
 480
 481       else
 482          Result :=
 483            pthread_cond_wait
 484              (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 485          pragma Assert (Result = 0);
 486       end if;
 487
 488       Yielded := True;
 489
 490       if not Self_ID.Common.LL.AST_Pending then
 491          Timedout := True;
 492       else
 493          Sys_Cantim (Status, To_Address (Self_ID), 0);
 494          pragma Assert ((Status and 1) = 1);
 495       end if;
 496    end Timed_Sleep;
 497
 498    -----------------
 499    -- Timed_Delay --
 500    -----------------
 501
 502    procedure Timed_Delay
 503      (Self_ID : Task_Id;
 504       Time    : Duration;
 505       Mode    : ST.Delay_Modes)
 506    is
 507       Sleep_Time : OS_Time;
 508       Result     : Interfaces.C.int;
 509       Status     : Cond_Value_Type;
 510       Yielded    : Boolean := False;
 511
 512    begin
 513       if Single_Lock then
 514          Lock_RTS;
 515       end if;
 516
 517       --  More comments required in body below ???
 518
 519       Write_Lock (Self_ID);
 520
 521       if Time /= 0.0 or else Mode /= Relative then
 522          Sleep_Time := To_OS_Time (Time, Mode);
 523
 524          if Mode = Relative or else OS_Clock <= Sleep_Time then
 525             Self_ID.Common.State := Delay_Sleep;
 526             Self_ID.Common.LL.AST_Pending := True;
 527
 528             Sys_Setimr
 529              (Status, 0, Sleep_Time,
 530               Timer_Sleep_AST'Access, To_Address (Self_ID), 0);
 531
 532             --  Comment following test
 533
 534             if (Status and 1) /= 1 then
 535                raise Storage_Error;
 536             end if;
 537
 538             loop
 539                if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
 540                   Sys_Cantim (Status, To_Address (Self_ID), 0);
 541                   pragma Assert ((Status and 1) = 1);
 542                   exit;
 543                end if;
 544
 545                if Single_Lock then
 546                   Result :=
 547                     pthread_cond_wait
 548                       (Self_ID.Common.LL.CV'Access,
 549                        Single_RTS_Lock'Access);
 550                   pragma Assert (Result = 0);
 551                else
 552                   Result :=
 553                     pthread_cond_wait
 554                       (Self_ID.Common.LL.CV'Access,
 555                        Self_ID.Common.LL.L'Access);
 556                   pragma Assert (Result = 0);
 557                end if;
 558
 559                Yielded := True;
 560
 561                exit when not Self_ID.Common.LL.AST_Pending;
 562             end loop;
 563
 564             Self_ID.Common.State := Runnable;
 565          end if;
 566       end if;
 567
 568       Unlock (Self_ID);
 569
 570       if Single_Lock then
 571          Unlock_RTS;
 572       end if;
 573
 574       if not Yielded then
 575          Result := sched_yield;
 576          pragma Assert (Result = 0);
 577       end if;
 578    end Timed_Delay;
 579
 580    ---------------------
 581    -- Monotonic_Clock --
 582    ---------------------
 583
 584    function Monotonic_Clock return Duration
 585      renames System.OS_Primitives.Monotonic_Clock;
 586
 587    -------------------
 588    -- RT_Resolution --
 589    -------------------
 590
 591    function RT_Resolution return Duration is
 592    begin
 593       --  Document origin of this magic constant ???
 594       return 10#1.0#E-3;
 595    end RT_Resolution;
 596
 597    ------------
 598    -- Wakeup --
 599    ------------
 600
 601    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 602       pragma Unreferenced (Reason);
 603       Result : Interfaces.C.int;
 604    begin
 605       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 606       pragma Assert (Result = 0);
 607    end Wakeup;
 608
 609    -----------
 610    -- Yield --
 611    -----------
 612
 613    procedure Yield (Do_Yield : Boolean := True) is
 614       Result : Interfaces.C.int;
 615       pragma Unreferenced (Result);
 616    begin
 617       if Do_Yield then
 618          Result := sched_yield;
 619       end if;
 620    end Yield;
 621
 622    ------------------
 623    -- Set_Priority --
 624    ------------------
 625
 626    procedure Set_Priority
 627      (T                   : Task_Id;
 628       Prio                : System.Any_Priority;
 629       Loss_Of_Inheritance : Boolean := False)
 630    is
 631       pragma Unreferenced (Loss_Of_Inheritance);
 632
 633       Result : Interfaces.C.int;
 634       Param  : aliased struct_sched_param;
 635
 636       function Get_Policy (Prio : System.Any_Priority) return Character;
 637       pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 638       --  Get priority specific dispatching policy
 639
 640       Priority_Specific_Policy : constant Character := Get_Policy (Prio);
 641       --  Upper case first character of the policy name corresponding to the
 642       --  task as set by a Priority_Specific_Dispatching pragma.
 643
 644    begin
 645       T.Common.Current_Priority := Prio;
 646       Param.sched_priority := Interfaces.C.int (Underlying_Priorities (Prio));
 647
 648       if Dispatching_Policy = 'R'
 649         or else Priority_Specific_Policy = 'R'
 650         or else Time_Slice_Val > 0
 651       then
 652          Result :=
 653            pthread_setschedparam
 654              (T.Common.LL.Thread, SCHED_RR, Param'Access);
 655
 656       elsif Dispatching_Policy = 'F'
 657         or else Priority_Specific_Policy = 'F'
 658         or else Time_Slice_Val = 0
 659       then
 660          Result :=
 661            pthread_setschedparam
 662              (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 663
 664       else
 665          --  SCHED_OTHER priorities are restricted to the range 8 - 15.
 666          --  Since the translation from Underlying priorities results
 667          --  in a range of 16 - 31, dividing by 2 gives the correct result.
 668
 669          Param.sched_priority := Param.sched_priority / 2;
 670          Result :=
 671            pthread_setschedparam
 672              (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 673       end if;
 674
 675       pragma Assert (Result = 0);
 676    end Set_Priority;
 677
 678    ------------------
 679    -- Get_Priority --
 680    ------------------
 681
 682    function Get_Priority (T : Task_Id) return System.Any_Priority is
 683    begin
 684       return T.Common.Current_Priority;
 685    end Get_Priority;
 686
 687    ----------------
 688    -- Enter_Task --
 689    ----------------
 690
 691    procedure Enter_Task (Self_ID : Task_Id) is
 692    begin
 693       Self_ID.Common.LL.Thread := pthread_self;
 694
 695       Specific.Set (Self_ID);
 696
 697       Lock_RTS;
 698
 699       for J in Known_Tasks'Range loop
 700          if Known_Tasks (J) = null then
 701             Known_Tasks (J) := Self_ID;
 702             Self_ID.Known_Tasks_Index := J;
 703             exit;
 704          end if;
 705       end loop;
 706
 707       Unlock_RTS;
 708    end Enter_Task;
 709
 710    --------------
 711    -- New_ATCB --
 712    --------------
 713
 714    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 715    begin
 716       return new Ada_Task_Control_Block (Entry_Num);
 717    end New_ATCB;
 718
 719    -------------------
 720    -- Is_Valid_Task --
 721    -------------------
 722
 723    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 724
 725    -----------------------------
 726    -- Register_Foreign_Thread --
 727    -----------------------------
 728
 729    function Register_Foreign_Thread return Task_Id is
 730    begin
 731       if Is_Valid_Task then
 732          return Self;
 733       else
 734          return Register_Foreign_Thread (pthread_self);
 735       end if;
 736    end Register_Foreign_Thread;
 737
 738    --------------------
 739    -- Initialize_TCB --
 740    --------------------
 741
 742    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 743       Mutex_Attr : aliased pthread_mutexattr_t;
 744       Result     : Interfaces.C.int;
 745       Cond_Attr  : aliased pthread_condattr_t;
 746
 747    begin
 748       --  More comments required in body below ???
 749
 750       if not Single_Lock then
 751          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 752          pragma Assert (Result = 0 or else Result = ENOMEM);
 753
 754          if Result = 0 then
 755             Result :=
 756               pthread_mutex_init
 757                 (Self_ID.Common.LL.L'Access, Mutex_Attr'Access);
 758             pragma Assert (Result = 0 or else Result = ENOMEM);
 759          end if;
 760
 761          if Result /= 0 then
 762             Succeeded := False;
 763             return;
 764          end if;
 765
 766          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 767          pragma Assert (Result = 0);
 768       end if;
 769
 770       Result := pthread_condattr_init (Cond_Attr'Access);
 771       pragma Assert (Result = 0 or else Result = ENOMEM);
 772
 773       if Result = 0 then
 774          Result :=
 775            pthread_cond_init
 776              (Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
 777          pragma Assert (Result = 0 or else Result = ENOMEM);
 778       end if;
 779
 780       if Result = 0 then
 781          Succeeded := True;
 782          Self_ID.Common.LL.Exc_Stack_Ptr := new Exc_Stack_T;
 783
 784       else
 785          if not Single_Lock then
 786             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 787             pragma Assert (Result = 0);
 788          end if;
 789
 790          Succeeded := False;
 791       end if;
 792
 793       Result := pthread_condattr_destroy (Cond_Attr'Access);
 794       pragma Assert (Result = 0);
 795    end Initialize_TCB;
 796
 797    ------------------------
 798    -- Get_Exc_Stack_Addr --
 799    ------------------------
 800
 801    function Get_Exc_Stack_Addr return Address is
 802    begin
 803       return Self.Common.LL.Exc_Stack_Ptr (Exc_Stack_T'Last)'Address;
 804    end Get_Exc_Stack_Addr;
 805
 806    -----------------
 807    -- Create_Task --
 808    -----------------
 809
 810    procedure Create_Task
 811      (T          : Task_Id;
 812       Wrapper    : System.Address;
 813       Stack_Size : System.Parameters.Size_Type;
 814       Priority   : System.Any_Priority;
 815       Succeeded  : out Boolean)
 816    is
 817       Attributes : aliased pthread_attr_t;
 818       Result     : Interfaces.C.int;
 819
 820       function Thread_Body_Access is new
 821         Ada.Unchecked_Conversion (System.Aux_DEC.Short_Address, Thread_Body);
 822
 823    begin
 824       --  Since the initial signal mask of a thread is inherited from the
 825       --  creator, we need to set our local signal mask mask all signals
 826       --  during the creation operation, to make sure the new thread is
 827       --  not disturbed by signals before it has set its own Task_Id.
 828
 829       Result := pthread_attr_init (Attributes'Access);
 830       pragma Assert (Result = 0 or else Result = ENOMEM);
 831
 832       if Result /= 0 then
 833          Succeeded := False;
 834          return;
 835       end if;
 836
 837       Result := pthread_attr_setdetachstate
 838         (Attributes'Access, PTHREAD_CREATE_DETACHED);
 839       pragma Assert (Result = 0);
 840
 841       Result := pthread_attr_setstacksize
 842         (Attributes'Access, Interfaces.C.size_t (Stack_Size));
 843       pragma Assert (Result = 0);
 844
 845       --  This call may be unnecessary, not sure. ???
 846
 847       Result :=
 848         pthread_attr_setinheritsched
 849           (Attributes'Access, PTHREAD_EXPLICIT_SCHED);
 850       pragma Assert (Result = 0);
 851
 852       Result :=
 853         pthread_create
 854           (T.Common.LL.Thread'Access,
 855            Attributes'Access,
 856            Thread_Body_Access (Wrapper),
 857            To_Address (T));
 858
 859       --  ENOMEM is a valid run-time error -- do not shut down
 860
 861       pragma Assert (Result = 0
 862         or else Result = EAGAIN or else Result = ENOMEM);
 863
 864       Succeeded := Result = 0;
 865
 866       Result := pthread_attr_destroy (Attributes'Access);
 867       pragma Assert (Result = 0);
 868
 869       if Succeeded then
 870          Set_Priority (T, Priority);
 871       end if;
 872    end Create_Task;
 873
 874    ------------------
 875    -- Finalize_TCB --
 876    ------------------
 877
 878    procedure Finalize_TCB (T : Task_Id) is
 879       Result  : Interfaces.C.int;
 880       Tmp     : Task_Id := T;
 881       Is_Self : constant Boolean := T = Self;
 882
 883       procedure Free is new
 884         Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 885
 886       procedure Free is new Ada.Unchecked_Deallocation
 887        (Exc_Stack_T, Exc_Stack_Ptr_T);
 888
 889    begin
 890       if not Single_Lock then
 891          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
 892          pragma Assert (Result = 0);
 893       end if;
 894
 895       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
 896       pragma Assert (Result = 0);
 897
 898       if T.Known_Tasks_Index /= -1 then
 899          Known_Tasks (T.Known_Tasks_Index) := null;
 900       end if;
 901
 902       Free (T.Common.LL.Exc_Stack_Ptr);
 903       Free (Tmp);
 904
 905       if Is_Self then
 906          Specific.Set (null);
 907       end if;
 908    end Finalize_TCB;
 909
 910    ---------------
 911    -- Exit_Task --
 912    ---------------
 913
 914    procedure Exit_Task is
 915    begin
 916       null;
 917    end Exit_Task;
 918
 919    ----------------
 920    -- Abort_Task --
 921    ----------------
 922
 923    procedure Abort_Task (T : Task_Id) is
 924    begin
 925       --  Interrupt Server_Tasks may be waiting on an event flag
 926
 927       if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then
 928          Wakeup (T, Interrupt_Server_Blocked_On_Event_Flag);
 929       end if;
 930    end Abort_Task;
 931
 932    ----------------
 933    -- Initialize --
 934    ----------------
 935
 936    procedure Initialize (S : in out Suspension_Object) is
 937       Mutex_Attr : aliased pthread_mutexattr_t;
 938       Cond_Attr  : aliased pthread_condattr_t;
 939       Result     : Interfaces.C.int;
 940    begin
 941       --  Initialize internal state (always to False (D.10 (6)))
 942
 943       S.State := False;
 944       S.Waiting := False;
 945
 946       --  Initialize internal mutex
 947
 948       Result := pthread_mutexattr_init (Mutex_Attr'Access);
 949       pragma Assert (Result = 0 or else Result = ENOMEM);
 950
 951       if Result = ENOMEM then
 952          raise Storage_Error;
 953       end if;
 954
 955       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
 956       pragma Assert (Result = 0 or else Result = ENOMEM);
 957
 958       if Result = ENOMEM then
 959          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 960          pragma Assert (Result = 0);
 961
 962          raise Storage_Error;
 963       end if;
 964
 965       Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 966       pragma Assert (Result = 0);
 967
 968       --  Initialize internal condition variable
 969
 970       Result := pthread_condattr_init (Cond_Attr'Access);
 971       pragma Assert (Result = 0 or else Result = ENOMEM);
 972
 973       if Result /= 0 then
 974          Result := pthread_mutex_destroy (S.L'Access);
 975          pragma Assert (Result = 0);
 976
 977          if Result = ENOMEM then
 978             raise Storage_Error;
 979          end if;
 980       end if;
 981
 982       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
 983       pragma Assert (Result = 0 or else Result = ENOMEM);
 984
 985       if Result /= 0 then
 986          Result := pthread_mutex_destroy (S.L'Access);
 987          pragma Assert (Result = 0);
 988
 989          if Result = ENOMEM then
 990             Result := pthread_condattr_destroy (Cond_Attr'Access);
 991             pragma Assert (Result = 0);
 992
 993             raise Storage_Error;
 994          end if;
 995       end if;
 996
 997       Result := pthread_condattr_destroy (Cond_Attr'Access);
 998       pragma Assert (Result = 0);
 999    end Initialize;
1000
1001    --------------
1002    -- Finalize --
1003    --------------
1004
1005    procedure Finalize (S : in out Suspension_Object) is
1006       Result : Interfaces.C.int;
1007
1008    begin
1009       --  Destroy internal mutex
1010
1011       Result := pthread_mutex_destroy (S.L'Access);
1012       pragma Assert (Result = 0);
1013
1014       --  Destroy internal condition variable
1015
1016       Result := pthread_cond_destroy (S.CV'Access);
1017       pragma Assert (Result = 0);
1018    end Finalize;
1019
1020    -------------------
1021    -- Current_State --
1022    -------------------
1023
1024    function Current_State (S : Suspension_Object) return Boolean is
1025    begin
1026       --  We do not want to use lock on this read operation. State is marked
1027       --  as Atomic so that we ensure that the value retrieved is correct.
1028
1029       return S.State;
1030    end Current_State;
1031
1032    ---------------
1033    -- Set_False --
1034    ---------------
1035
1036    procedure Set_False (S : in out Suspension_Object) is
1037       Result : Interfaces.C.int;
1038
1039    begin
1040       SSL.Abort_Defer.all;
1041
1042       Result := pthread_mutex_lock (S.L'Access);
1043       pragma Assert (Result = 0);
1044
1045       S.State := False;
1046
1047       Result := pthread_mutex_unlock (S.L'Access);
1048       pragma Assert (Result = 0);
1049
1050       SSL.Abort_Undefer.all;
1051    end Set_False;
1052
1053    --------------
1054    -- Set_True --
1055    --------------
1056
1057    procedure Set_True (S : in out Suspension_Object) is
1058       Result : Interfaces.C.int;
1059
1060    begin
1061       SSL.Abort_Defer.all;
1062
1063       Result := pthread_mutex_lock (S.L'Access);
1064       pragma Assert (Result = 0);
1065
1066       --  If there is already a task waiting on this suspension object then
1067       --  we resume it, leaving the state of the suspension object to False,
1068       --  as specified in (RM D.10(9)), otherwise leave state set to True.
1069
1070       if S.Waiting then
1071          S.Waiting := False;
1072          S.State := False;
1073
1074          Result := pthread_cond_signal (S.CV'Access);
1075          pragma Assert (Result = 0);
1076
1077       else
1078          S.State := True;
1079       end if;
1080
1081       Result := pthread_mutex_unlock (S.L'Access);
1082       pragma Assert (Result = 0);
1083
1084       SSL.Abort_Undefer.all;
1085    end Set_True;
1086
1087    ------------------------
1088    -- Suspend_Until_True --
1089    ------------------------
1090
1091    procedure Suspend_Until_True (S : in out Suspension_Object) is
1092       Result : Interfaces.C.int;
1093
1094    begin
1095       SSL.Abort_Defer.all;
1096
1097       Result := pthread_mutex_lock (S.L'Access);
1098       pragma Assert (Result = 0);
1099
1100       if S.Waiting then
1101
1102          --  Program_Error must be raised upon calling Suspend_Until_True
1103          --  if another task is already waiting on that suspension object
1104          --  (RM D.10(10)).
1105
1106          Result := pthread_mutex_unlock (S.L'Access);
1107          pragma Assert (Result = 0);
1108
1109          SSL.Abort_Undefer.all;
1110
1111          raise Program_Error;
1112
1113       else
1114          --  Suspend the task if the state is False. Otherwise, the task
1115          --  continues its execution, and the state of the suspension object
1116          --  is set to False (ARM D.10 par. 9).
1117
1118          if S.State then
1119             S.State := False;
1120          else
1121             S.Waiting := True;
1122             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1123          end if;
1124
1125          Result := pthread_mutex_unlock (S.L'Access);
1126          pragma Assert (Result = 0);
1127
1128          SSL.Abort_Undefer.all;
1129       end if;
1130    end Suspend_Until_True;
1131
1132    ----------------
1133    -- Check_Exit --
1134    ----------------
1135
1136    --  Dummy version
1137
1138    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1139       pragma Unreferenced (Self_ID);
1140    begin
1141       return True;
1142    end Check_Exit;
1143
1144    --------------------
1145    -- Check_No_Locks --
1146    --------------------
1147
1148    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1149       pragma Unreferenced (Self_ID);
1150    begin
1151       return True;
1152    end Check_No_Locks;
1153
1154    ----------------------
1155    -- Environment_Task --
1156    ----------------------
1157
1158    function Environment_Task return Task_Id is
1159    begin
1160       return Environment_Task_Id;
1161    end Environment_Task;
1162
1163    --------------
1164    -- Lock_RTS --
1165    --------------
1166
1167    procedure Lock_RTS is
1168    begin
1169       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1170    end Lock_RTS;
1171
1172    ----------------
1173    -- Unlock_RTS --
1174    ----------------
1175
1176    procedure Unlock_RTS is
1177    begin
1178       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1179    end Unlock_RTS;
1180
1181    ------------------
1182    -- Suspend_Task --
1183    ------------------
1184
1185    function Suspend_Task
1186      (T           : ST.Task_Id;
1187       Thread_Self : Thread_Id) return Boolean
1188    is
1189       pragma Unreferenced (T);
1190       pragma Unreferenced (Thread_Self);
1191    begin
1192       return False;
1193    end Suspend_Task;
1194
1195    -----------------
1196    -- Resume_Task --
1197    -----------------
1198
1199    function Resume_Task
1200      (T           : ST.Task_Id;
1201       Thread_Self : Thread_Id) return Boolean
1202    is
1203       pragma Unreferenced (T);
1204       pragma Unreferenced (Thread_Self);
1205    begin
1206       return False;
1207    end Resume_Task;
1208
1209    --------------------
1210    -- Stop_All_Tasks --
1211    --------------------
1212
1213    procedure Stop_All_Tasks is
1214    begin
1215       null;
1216    end Stop_All_Tasks;
1217
1218    ---------------
1219    -- Stop_Task --
1220    ---------------
1221
1222    function Stop_Task (T : ST.Task_Id) return Boolean is
1223       pragma Unreferenced (T);
1224    begin
1225       return False;
1226    end Stop_Task;
1227
1228    -------------------
1229    -- Continue_Task --
1230    -------------------
1231
1232    function Continue_Task (T : ST.Task_Id) return Boolean is
1233       pragma Unreferenced (T);
1234    begin
1235       return False;
1236    end Continue_Task;
1237
1238    ----------------
1239    -- Initialize --
1240    ----------------
1241
1242    procedure Initialize (Environment_Task : Task_Id) is
1243    begin
1244       Environment_Task_Id := Environment_Task;
1245
1246       SSL.Get_Exc_Stack_Addr := Get_Exc_Stack_Addr'Access;
1247
1248       --  Initialize the lock used to synchronize chain of all ATCBs
1249
1250       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1251
1252       Specific.Initialize (Environment_Task);
1253
1254       Enter_Task (Environment_Task);
1255    end Initialize;
1256
1257 end System.Task_Primitives.Operations;