gcc/ada/s-taprop-lynxos.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) 1992-2009, 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 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT 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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a LynxOS version of this file, adapted to make SCHED_FIFO and
  33 --  ceiling locking (Annex D compliance) work properly.
  34
  35 --  This package contains all the GNULL primitives that interface directly with
  36 --  the underlying OS.
  37
  38 pragma Polling (Off);
  39 --  Turn off polling, we do not want ATC polling to take place during tasking
  40 --  operations. It causes infinite loops and other problems.
  41
  42 with Ada.Unchecked_Deallocation;
  43
  44 with Interfaces.C;
  45
  46 with System.Tasking.Debug;
  47 with System.Interrupt_Management;
  48 with System.OS_Primitives;
  49 with System.Task_Info;
  50
  51 with System.Soft_Links;
  52 --  We use System.Soft_Links instead of System.Tasking.Initialization
  53 --  because the later is a higher level package that we shouldn't depend on.
  54 --  For example when using the restricted run time, it is replaced by
  55 --  System.Tasking.Restricted.Stages.
  56
  57 package body System.Task_Primitives.Operations is
  58
  59    package SSL renames System.Soft_Links;
  60
  61    use System.Tasking.Debug;
  62    use System.Tasking;
  63    use Interfaces.C;
  64    use System.OS_Interface;
  65    use System.Parameters;
  66    use System.OS_Primitives;
  67
  68    ----------------
  69    -- Local Data --
  70    ----------------
  71
  72    --  The followings are logically constants, but need to be initialized
  73    --  at run time.
  74
  75    Single_RTS_Lock : aliased RTS_Lock;
  76    --  This is a lock to allow only one thread of control in the RTS at
  77    --  a time; it is used to execute in mutual exclusion from all other tasks.
  78    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
  79
  80    ATCB_Key : aliased pthread_key_t;
  81    --  Key used to find the Ada Task_Id associated with a thread
  82
  83    Environment_Task_Id : Task_Id;
  84    --  A variable to hold Task_Id for the environment task
  85
  86    Locking_Policy : Character;
  87    pragma Import (C, Locking_Policy, "__gl_locking_policy");
  88    --  Value of the pragma Locking_Policy:
  89    --    'C' for Ceiling_Locking
  90    --    'I' for Inherit_Locking
  91    --    ' ' for none.
  92
  93    Unblocked_Signal_Mask : aliased sigset_t;
  94    --  The set of signals that should unblocked in all tasks
  95
  96    --  The followings are internal configuration constants needed
  97
  98    Next_Serial_Number : Task_Serial_Number := 100;
  99    --  We start at 100, to reserve some special values for
 100    --  using in error checking.
 101
 102    Time_Slice_Val : Integer;
 103    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 104
 105    Dispatching_Policy : Character;
 106    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 107
 108    Foreign_Task_Elaborated : aliased Boolean := True;
 109    --  Used to identified fake tasks (i.e., non-Ada Threads)
 110
 111    --------------------
 112    -- Local Packages --
 113    --------------------
 114
 115    package Specific is
 116
 117       procedure Initialize (Environment_Task : Task_Id);
 118       pragma Inline (Initialize);
 119       --  Initialize various data needed by this package
 120
 121       function Is_Valid_Task return Boolean;
 122       pragma Inline (Is_Valid_Task);
 123       --  Does the current thread have an ATCB?
 124
 125       procedure Set (Self_Id : Task_Id);
 126       pragma Inline (Set);
 127       --  Set the self id for the current task
 128
 129       function Self return Task_Id;
 130       pragma Inline (Self);
 131       --  Return a pointer to the Ada Task Control Block of the calling task
 132
 133    end Specific;
 134
 135    package body Specific is separate;
 136    --  The body of this package is target specific
 137
 138    ---------------------------------
 139    -- Support for foreign threads --
 140    ---------------------------------
 141
 142    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 143    --  Allocate and Initialize a new ATCB for the current Thread
 144
 145    function Register_Foreign_Thread
 146      (Thread : Thread_Id) return Task_Id is separate;
 147
 148    -----------------------
 149    -- Local Subprograms --
 150    -----------------------
 151
 152    procedure Abort_Handler (Sig : Signal);
 153    --  Signal handler used to implement asynchronous abort
 154
 155    procedure Set_OS_Priority (T : Task_Id; Prio : System.Any_Priority);
 156    --  This procedure calls the scheduler of the OS to set thread's priority
 157
 158    -------------------
 159    -- Abort_Handler --
 160    -------------------
 161
 162    procedure Abort_Handler (Sig : Signal) is
 163       pragma Unreferenced (Sig);
 164
 165       T       : constant Task_Id := Self;
 166       Result  : Interfaces.C.int;
 167       Old_Set : aliased sigset_t;
 168
 169    begin
 170       --  It is not safe to raise an exception when using ZCX and the GCC
 171       --  exception handling mechanism.
 172
 173       if ZCX_By_Default and then GCC_ZCX_Support then
 174          return;
 175       end if;
 176
 177       if T.Deferral_Level = 0
 178         and then T.Pending_ATC_Level < T.ATC_Nesting_Level
 179         and then not T.Aborting
 180       then
 181          T.Aborting := True;
 182
 183          --  Make sure signals used for RTS internal purpose are unmasked
 184
 185          Result :=
 186            pthread_sigmask
 187              (SIG_UNBLOCK,
 188               Unblocked_Signal_Mask'Access,
 189               Old_Set'Access);
 190          pragma Assert (Result = 0);
 191
 192          raise Standard'Abort_Signal;
 193       end if;
 194    end Abort_Handler;
 195
 196    -----------------
 197    -- Stack_Guard --
 198    -----------------
 199
 200    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 201       Stack_Base : constant Address := Get_Stack_Base (T.Common.LL.Thread);
 202       Guard_Page_Address : Address;
 203
 204       Res : Interfaces.C.int;
 205
 206    begin
 207       if Stack_Base_Available then
 208
 209          --  Compute the guard page address
 210
 211          Guard_Page_Address :=
 212            Stack_Base - (Stack_Base mod Get_Page_Size) + Get_Page_Size;
 213
 214          if On then
 215             Res := mprotect (Guard_Page_Address, Get_Page_Size, PROT_ON);
 216          else
 217             Res := mprotect (Guard_Page_Address, Get_Page_Size, PROT_OFF);
 218          end if;
 219
 220          pragma Assert (Res = 0);
 221       end if;
 222    end Stack_Guard;
 223
 224    --------------------
 225    -- Get_Thread_Id  --
 226    --------------------
 227
 228    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 229    begin
 230       return T.Common.LL.Thread;
 231    end Get_Thread_Id;
 232
 233    ----------
 234    -- Self --
 235    ----------
 236
 237    function Self return Task_Id renames Specific.Self;
 238
 239    ---------------------
 240    -- Initialize_Lock --
 241    ---------------------
 242
 243    procedure Initialize_Lock
 244      (Prio : System.Any_Priority;
 245       L    : not null access Lock)
 246    is
 247       Attributes : aliased pthread_mutexattr_t;
 248       Result : Interfaces.C.int;
 249
 250    begin
 251       Result := pthread_mutexattr_init (Attributes'Access);
 252       pragma Assert (Result = 0 or else Result = ENOMEM);
 253
 254       if Result = ENOMEM then
 255          raise Storage_Error;
 256       end if;
 257
 258       if Locking_Policy = 'C' then
 259          L.Ceiling := Prio;
 260       end if;
 261
 262       Result := pthread_mutex_init (L.Mutex'Access, Attributes'Access);
 263       pragma Assert (Result = 0 or else Result = ENOMEM);
 264
 265       if Result = ENOMEM then
 266          raise Storage_Error;
 267       end if;
 268
 269       Result := pthread_mutexattr_destroy (Attributes'Access);
 270       pragma Assert (Result = 0);
 271    end Initialize_Lock;
 272
 273    procedure Initialize_Lock
 274      (L     : not null access RTS_Lock;
 275       Level : Lock_Level)
 276    is
 277       pragma Unreferenced (Level);
 278
 279       Attributes : aliased pthread_mutexattr_t;
 280       Result     : Interfaces.C.int;
 281
 282    begin
 283       Result := pthread_mutexattr_init (Attributes'Access);
 284       pragma Assert (Result = 0 or else Result = ENOMEM);
 285
 286       if Result = ENOMEM then
 287          raise Storage_Error;
 288       end if;
 289
 290       Result := pthread_mutex_init (L, Attributes'Access);
 291       pragma Assert (Result = 0 or else Result = ENOMEM);
 292
 293       if Result = ENOMEM then
 294          Result := pthread_mutexattr_destroy (Attributes'Access);
 295          raise Storage_Error;
 296       end if;
 297
 298       Result := pthread_mutexattr_destroy (Attributes'Access);
 299       pragma Assert (Result = 0);
 300    end Initialize_Lock;
 301
 302    -------------------
 303    -- Finalize_Lock --
 304    -------------------
 305
 306    procedure Finalize_Lock (L : not null access Lock) is
 307       Result : Interfaces.C.int;
 308    begin
 309       Result := pthread_mutex_destroy (L.Mutex'Access);
 310       pragma Assert (Result = 0);
 311    end Finalize_Lock;
 312
 313    procedure Finalize_Lock (L : not null access RTS_Lock) is
 314       Result : Interfaces.C.int;
 315    begin
 316       Result := pthread_mutex_destroy (L);
 317       pragma Assert (Result = 0);
 318    end Finalize_Lock;
 319
 320    ----------------
 321    -- Write_Lock --
 322    ----------------
 323
 324    procedure Write_Lock
 325      (L                 : not null access Lock;
 326       Ceiling_Violation : out Boolean)
 327    is
 328       Result : Interfaces.C.int;
 329       T      : constant Task_Id := Self;
 330
 331    begin
 332       if Locking_Policy = 'C' then
 333          if T.Common.Current_Priority > L.Ceiling then
 334             Ceiling_Violation := True;
 335             return;
 336          end if;
 337
 338          L.Saved_Priority := T.Common.Current_Priority;
 339
 340          if T.Common.Current_Priority < L.Ceiling then
 341             Set_OS_Priority (T, L.Ceiling);
 342          end if;
 343       end if;
 344
 345       Result := pthread_mutex_lock (L.Mutex'Access);
 346
 347       --  Assume that the cause of EINVAL is a priority ceiling violation
 348
 349       Ceiling_Violation := (Result = EINVAL);
 350       pragma Assert (Result = 0 or else Result = EINVAL);
 351    end Write_Lock;
 352
 353    --  No tricks on RTS_Locks
 354
 355    procedure Write_Lock
 356      (L           : not null access RTS_Lock;
 357       Global_Lock : Boolean := False)
 358    is
 359       Result : Interfaces.C.int;
 360    begin
 361       if not Single_Lock or else Global_Lock then
 362          Result := pthread_mutex_lock (L);
 363          pragma Assert (Result = 0);
 364       end if;
 365    end Write_Lock;
 366
 367    procedure Write_Lock (T : Task_Id) is
 368       Result : Interfaces.C.int;
 369    begin
 370       if not Single_Lock then
 371          Result := pthread_mutex_lock (T.Common.LL.L'Access);
 372          pragma Assert (Result = 0);
 373       end if;
 374    end Write_Lock;
 375
 376    ---------------
 377    -- Read_Lock --
 378    ---------------
 379
 380    procedure Read_Lock
 381      (L                 : not null access Lock;
 382       Ceiling_Violation : out Boolean)
 383    is
 384    begin
 385       Write_Lock (L, Ceiling_Violation);
 386    end Read_Lock;
 387
 388    ------------
 389    -- Unlock --
 390    ------------
 391
 392    procedure Unlock (L : not null access Lock) is
 393       Result : Interfaces.C.int;
 394       T      : constant Task_Id := Self;
 395
 396    begin
 397       Result := pthread_mutex_unlock (L.Mutex'Access);
 398       pragma Assert (Result = 0);
 399
 400       if Locking_Policy = 'C' then
 401          if T.Common.Current_Priority > L.Saved_Priority then
 402             Set_OS_Priority (T, L.Saved_Priority);
 403          end if;
 404       end if;
 405    end Unlock;
 406
 407    procedure Unlock
 408      (L           : not null access RTS_Lock;
 409       Global_Lock : Boolean := False)
 410    is
 411       Result : Interfaces.C.int;
 412    begin
 413       if not Single_Lock or else Global_Lock then
 414          Result := pthread_mutex_unlock (L);
 415          pragma Assert (Result = 0);
 416       end if;
 417    end Unlock;
 418
 419    procedure Unlock (T : Task_Id) is
 420       Result : Interfaces.C.int;
 421    begin
 422       if not Single_Lock then
 423          Result := pthread_mutex_unlock (T.Common.LL.L'Access);
 424          pragma Assert (Result = 0);
 425       end if;
 426    end Unlock;
 427
 428    -----------------
 429    -- Set_Ceiling --
 430    -----------------
 431
 432    --  Dynamic priority ceilings are not supported by the underlying system
 433
 434    procedure Set_Ceiling
 435      (L    : not null access Lock;
 436       Prio : System.Any_Priority)
 437    is
 438       pragma Unreferenced (L, Prio);
 439    begin
 440       null;
 441    end Set_Ceiling;
 442
 443    -----------
 444    -- Sleep --
 445    -----------
 446
 447    procedure Sleep
 448      (Self_ID : Task_Id;
 449       Reason  : System.Tasking.Task_States)
 450    is
 451       pragma Unreferenced (Reason);
 452       Result : Interfaces.C.int;
 453
 454    begin
 455       if Single_Lock then
 456          Result :=
 457            pthread_cond_wait
 458              (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 459       else
 460          Result :=
 461            pthread_cond_wait
 462              (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 463       end if;
 464
 465       --  EINTR is not considered a failure
 466
 467       pragma Assert (Result = 0 or else Result = EINTR);
 468    end Sleep;
 469
 470    -----------------
 471    -- Timed_Sleep --
 472    -----------------
 473
 474    --  This is for use within the run-time system, so abort is
 475    --  assumed to be already deferred, and the caller should be
 476    --  holding its own ATCB lock.
 477
 478    procedure Timed_Sleep
 479      (Self_ID  : Task_Id;
 480       Time     : Duration;
 481       Mode     : ST.Delay_Modes;
 482       Reason   : Task_States;
 483       Timedout : out Boolean;
 484       Yielded  : out Boolean)
 485    is
 486       pragma Unreferenced (Reason);
 487
 488       Base_Time  : constant Duration := Monotonic_Clock;
 489       Check_Time : Duration := Base_Time;
 490       Rel_Time   : Duration;
 491       Abs_Time   : Duration;
 492       Request    : aliased timespec;
 493       Result     : Interfaces.C.int;
 494
 495    begin
 496       Timedout := True;
 497       Yielded := False;
 498
 499       if Mode = Relative then
 500          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 501
 502          if Relative_Timed_Wait then
 503             Rel_Time := Duration'Min (Max_Sensible_Delay, Time);
 504          end if;
 505
 506       else
 507          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 508
 509          if Relative_Timed_Wait then
 510             Rel_Time := Duration'Min (Max_Sensible_Delay, Time - Check_Time);
 511          end if;
 512       end if;
 513
 514       if Abs_Time > Check_Time then
 515          if Relative_Timed_Wait then
 516             Request := To_Timespec (Rel_Time);
 517          else
 518             Request := To_Timespec (Abs_Time);
 519          end if;
 520
 521          loop
 522             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 523
 524             if Single_Lock then
 525                Result :=
 526                  pthread_cond_timedwait
 527                    (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
 528                     Request'Access);
 529
 530             else
 531                Result :=
 532                  pthread_cond_timedwait
 533                    (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
 534                     Request'Access);
 535             end if;
 536
 537             Check_Time := Monotonic_Clock;
 538             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 539
 540             if Result = 0 or Result = EINTR then
 541
 542                --  Somebody may have called Wakeup for us
 543
 544                Timedout := False;
 545                exit;
 546             end if;
 547
 548             pragma Assert (Result = ETIMEDOUT);
 549          end loop;
 550       end if;
 551    end Timed_Sleep;
 552
 553    -----------------
 554    -- Timed_Delay --
 555    -----------------
 556
 557    --  This is for use in implementing delay statements, so we assume
 558    --  the caller is abort-deferred but is holding no locks.
 559
 560    procedure Timed_Delay
 561      (Self_ID : Task_Id;
 562       Time    : Duration;
 563       Mode    : ST.Delay_Modes)
 564    is
 565       Base_Time  : constant Duration := Monotonic_Clock;
 566       Check_Time : Duration := Base_Time;
 567       Abs_Time   : Duration;
 568       Rel_Time   : Duration;
 569       Request    : aliased timespec;
 570
 571       Result : Interfaces.C.int;
 572       pragma Warnings (Off, Result);
 573
 574    begin
 575       if Single_Lock then
 576          Lock_RTS;
 577       end if;
 578
 579       --  Comments needed in code below ???
 580
 581       Write_Lock (Self_ID);
 582
 583       if Mode = Relative then
 584          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 585
 586          if Relative_Timed_Wait then
 587             Rel_Time := Duration'Min (Max_Sensible_Delay, Time);
 588          end if;
 589
 590       else
 591          Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
 592
 593          if Relative_Timed_Wait then
 594             Rel_Time := Duration'Min (Max_Sensible_Delay, Time - Check_Time);
 595          end if;
 596       end if;
 597
 598       if Abs_Time > Check_Time then
 599          if Relative_Timed_Wait then
 600             Request := To_Timespec (Rel_Time);
 601          else
 602             Request := To_Timespec (Abs_Time);
 603          end if;
 604
 605          Self_ID.Common.State := Delay_Sleep;
 606
 607          loop
 608             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 609
 610             if Single_Lock then
 611                Result :=
 612                  pthread_cond_timedwait
 613                    (Self_ID.Common.LL.CV'Access,
 614                     Single_RTS_Lock'Access,
 615                     Request'Access);
 616             else
 617                Result :=
 618                  pthread_cond_timedwait
 619                    (Self_ID.Common.LL.CV'Access,
 620                     Self_ID.Common.LL.L'Access,
 621                     Request'Access);
 622             end if;
 623
 624             Check_Time := Monotonic_Clock;
 625             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 626
 627             pragma Assert (Result = 0         or else
 628                            Result = ETIMEDOUT or else
 629                            Result = EINTR);
 630          end loop;
 631
 632          Self_ID.Common.State := Runnable;
 633       end if;
 634
 635       Unlock (Self_ID);
 636
 637       if Single_Lock then
 638          Unlock_RTS;
 639       end if;
 640
 641       Result := sched_yield;
 642    end Timed_Delay;
 643
 644    ---------------------
 645    -- Monotonic_Clock --
 646    ---------------------
 647
 648    function Monotonic_Clock return Duration is
 649       TS     : aliased timespec;
 650       Result : Interfaces.C.int;
 651    begin
 652       Result :=
 653         clock_gettime
 654           (clock_id => CLOCK_REALTIME, tp => TS'Unchecked_Access);
 655       pragma Assert (Result = 0);
 656       return To_Duration (TS);
 657    end Monotonic_Clock;
 658
 659    -------------------
 660    -- RT_Resolution --
 661    -------------------
 662
 663    function RT_Resolution return Duration is
 664       Res    : aliased timespec;
 665       Result : Interfaces.C.int;
 666    begin
 667       Result :=
 668         clock_getres
 669           (clock_id => CLOCK_REALTIME, res => Res'Unchecked_Access);
 670       pragma Assert (Result = 0);
 671       return To_Duration (Res);
 672    end RT_Resolution;
 673
 674    ------------
 675    -- Wakeup --
 676    ------------
 677
 678    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 679       pragma Unreferenced (Reason);
 680       Result : Interfaces.C.int;
 681    begin
 682       Result := pthread_cond_signal (T.Common.LL.CV'Access);
 683       pragma Assert (Result = 0);
 684    end Wakeup;
 685
 686    -----------
 687    -- Yield --
 688    -----------
 689
 690    procedure Yield (Do_Yield : Boolean := True) is
 691       Result : Interfaces.C.int;
 692       pragma Unreferenced (Result);
 693    begin
 694       if Do_Yield then
 695          Result := sched_yield;
 696       end if;
 697    end Yield;
 698
 699    ------------------
 700    -- Set_Priority --
 701    ------------------
 702
 703    procedure Set_OS_Priority (T : Task_Id; Prio : System.Any_Priority) is
 704       Result : Interfaces.C.int;
 705       Param  : aliased struct_sched_param;
 706
 707       function Get_Policy (Prio : System.Any_Priority) return Character;
 708       pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 709       --  Get priority specific dispatching policy
 710
 711       Priority_Specific_Policy : constant Character := Get_Policy (Prio);
 712       --  Upper case first character of the policy name corresponding to the
 713       --  task as set by a Priority_Specific_Dispatching pragma.
 714
 715    begin
 716       Param.sched_priority := Interfaces.C.int (Prio);
 717
 718       if Time_Slice_Supported
 719         and then (Dispatching_Policy = 'R'
 720                    or else Priority_Specific_Policy = 'R'
 721                    or else Time_Slice_Val > 0)
 722       then
 723          Result :=
 724            pthread_setschedparam
 725              (T.Common.LL.Thread, SCHED_RR, Param'Access);
 726
 727       elsif Dispatching_Policy = 'F'
 728         or else Priority_Specific_Policy = 'F'
 729         or else Time_Slice_Val = 0
 730       then
 731          Result :=
 732            pthread_setschedparam
 733              (T.Common.LL.Thread, SCHED_FIFO, Param'Access);
 734
 735       else
 736          Result :=
 737            pthread_setschedparam
 738              (T.Common.LL.Thread, SCHED_OTHER, Param'Access);
 739       end if;
 740
 741       pragma Assert (Result = 0);
 742    end Set_OS_Priority;
 743
 744    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 745    pragma Atomic_Components (Prio_Array_Type);
 746    Prio_Array : Prio_Array_Type;
 747    --  Comments needed for these declarations ???
 748
 749    procedure Set_Priority
 750      (T                   : Task_Id;
 751       Prio                : System.Any_Priority;
 752       Loss_Of_Inheritance : Boolean := False)
 753    is
 754       Array_Item : Integer;
 755
 756    begin
 757       Set_OS_Priority (T, Prio);
 758
 759       if Locking_Policy = 'C' then
 760
 761          --  Annex D requirements: loss of inheritance puts task at the start
 762          --  of the queue for that prio; copied from 5ztaprop (VxWorks).
 763
 764          if Loss_Of_Inheritance
 765            and then Prio < T.Common.Current_Priority then
 766
 767             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 768             Prio_Array (T.Common.Base_Priority) := Array_Item;
 769
 770             loop
 771                Yield;
 772                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 773                  or else Prio_Array (T.Common.Base_Priority) = 1;
 774             end loop;
 775
 776             Prio_Array (T.Common.Base_Priority) :=
 777               Prio_Array (T.Common.Base_Priority) - 1;
 778          end if;
 779       end if;
 780
 781       T.Common.Current_Priority := Prio;
 782    end Set_Priority;
 783
 784    ------------------
 785    -- Get_Priority --
 786    ------------------
 787
 788    function Get_Priority (T : Task_Id) return System.Any_Priority is
 789    begin
 790       return T.Common.Current_Priority;
 791    end Get_Priority;
 792
 793    ----------------
 794    -- Enter_Task --
 795    ----------------
 796
 797    procedure Enter_Task (Self_ID : Task_Id) is
 798    begin
 799       Self_ID.Common.LL.Thread := pthread_self;
 800       Self_ID.Common.LL.LWP := lwp_self;
 801
 802       Specific.Set (Self_ID);
 803
 804       Lock_RTS;
 805
 806       for J in Known_Tasks'Range loop
 807          if Known_Tasks (J) = null then
 808             Known_Tasks (J) := Self_ID;
 809             Self_ID.Known_Tasks_Index := J;
 810             exit;
 811          end if;
 812       end loop;
 813
 814       Unlock_RTS;
 815    end Enter_Task;
 816
 817    --------------
 818    -- New_ATCB --
 819    --------------
 820
 821    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 822    begin
 823       return new Ada_Task_Control_Block (Entry_Num);
 824    end New_ATCB;
 825
 826    -------------------
 827    -- Is_Valid_Task --
 828    -------------------
 829
 830    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 831
 832    -----------------------------
 833    -- Register_Foreign_Thread --
 834    -----------------------------
 835
 836    function Register_Foreign_Thread return Task_Id is
 837    begin
 838       if Is_Valid_Task then
 839          return Self;
 840       else
 841          return Register_Foreign_Thread (pthread_self);
 842       end if;
 843    end Register_Foreign_Thread;
 844
 845    --------------------
 846    -- Initialize_TCB --
 847    --------------------
 848
 849    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 850       Mutex_Attr : aliased pthread_mutexattr_t;
 851       Result     : Interfaces.C.int;
 852       Cond_Attr  : aliased pthread_condattr_t;
 853
 854    begin
 855       --  Give the task a unique serial number
 856
 857       Self_ID.Serial_Number := Next_Serial_Number;
 858       Next_Serial_Number := Next_Serial_Number + 1;
 859       pragma Assert (Next_Serial_Number /= 0);
 860
 861       if not Single_Lock then
 862          Result := pthread_mutexattr_init (Mutex_Attr'Access);
 863          pragma Assert (Result = 0 or else Result = ENOMEM);
 864
 865          if Result = 0 then
 866             Result :=
 867               pthread_mutex_init
 868                 (Self_ID.Common.LL.L'Access, Mutex_Attr'Access);
 869             pragma Assert (Result = 0 or else Result = ENOMEM);
 870          end if;
 871
 872          if Result /= 0 then
 873             Succeeded := False;
 874             return;
 875          end if;
 876
 877          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
 878          pragma Assert (Result = 0);
 879       end if;
 880
 881       Result := pthread_condattr_init (Cond_Attr'Access);
 882       pragma Assert (Result = 0 or else Result = ENOMEM);
 883
 884       if Result = 0 then
 885          Result :=
 886            pthread_cond_init (Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
 887          pragma Assert (Result = 0 or else Result = ENOMEM);
 888       end if;
 889
 890       if Result = 0 then
 891          Succeeded := True;
 892       else
 893          if not Single_Lock then
 894             Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
 895             pragma Assert (Result = 0);
 896          end if;
 897
 898          Succeeded := False;
 899       end if;
 900
 901       Result := pthread_condattr_destroy (Cond_Attr'Access);
 902       pragma Assert (Result = 0);
 903    end Initialize_TCB;
 904
 905    -----------------
 906    -- Create_Task --
 907    -----------------
 908
 909    procedure Create_Task
 910      (T          : Task_Id;
 911       Wrapper    : System.Address;
 912       Stack_Size : System.Parameters.Size_Type;
 913       Priority   : System.Any_Priority;
 914       Succeeded  : out Boolean)
 915    is
 916       Attributes          : aliased pthread_attr_t;
 917       Adjusted_Stack_Size : Interfaces.C.size_t;
 918       Result              : Interfaces.C.int;
 919
 920       use System.Task_Info;
 921
 922    begin
 923       Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
 924
 925       if Stack_Base_Available then
 926
 927          --  If Stack Checking is supported then allocate 2 additional pages:
 928
 929          --  In the worst case, stack is allocated at something like
 930          --  N * Get_Page_Size - epsilon, we need to add the size for 2 pages
 931          --  to be sure the effective stack size is greater than what
 932          --  has been asked.
 933
 934          Adjusted_Stack_Size := Adjusted_Stack_Size + 2 * Get_Page_Size;
 935       end if;
 936
 937       Result := pthread_attr_init (Attributes'Access);
 938       pragma Assert (Result = 0 or else Result = ENOMEM);
 939
 940       if Result /= 0 then
 941          Succeeded := False;
 942          return;
 943       end if;
 944
 945       Result :=
 946         pthread_attr_setdetachstate
 947           (Attributes'Access, PTHREAD_CREATE_DETACHED);
 948       pragma Assert (Result = 0);
 949
 950       Result :=
 951         pthread_attr_setstacksize
 952           (Attributes'Access, Adjusted_Stack_Size);
 953       pragma Assert (Result = 0);
 954
 955       if T.Common.Task_Info /= Default_Scope then
 956
 957          --  We are assuming that Scope_Type has the same values than the
 958          --  corresponding C macros
 959
 960          Result :=
 961            pthread_attr_setscope
 962              (Attributes'Access, Task_Info_Type'Pos (T.Common.Task_Info));
 963          pragma Assert (Result = 0);
 964       end if;
 965
 966       --  Since the initial signal mask of a thread is inherited from the
 967       --  creator, and the Environment task has all its signals masked, we
 968       --  do not need to manipulate caller's signal mask at this point.
 969       --  All tasks in RTS will have All_Tasks_Mask initially.
 970
 971       Result :=
 972         pthread_create
 973           (T.Common.LL.Thread'Access,
 974            Attributes'Access,
 975            Thread_Body_Access (Wrapper),
 976            To_Address (T));
 977       pragma Assert (Result = 0 or else Result = EAGAIN);
 978
 979       Succeeded := Result = 0;
 980
 981       Result := pthread_attr_destroy (Attributes'Access);
 982       pragma Assert (Result = 0);
 983
 984       if Succeeded then
 985          Set_Priority (T, Priority);
 986       end if;
 987    end Create_Task;
 988
 989    ------------------
 990    -- Finalize_TCB --
 991    ------------------
 992
 993    procedure Finalize_TCB (T : Task_Id) is
 994       Result : Interfaces.C.int;
 995       Tmp    : Task_Id := T;
 996       Is_Self : constant Boolean := T = Self;
 997
 998       procedure Free is new
 999         Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
1000
1001    begin
1002       if not Single_Lock then
1003          Result := pthread_mutex_destroy (T.Common.LL.L'Access);
1004          pragma Assert (Result = 0);
1005       end if;
1006
1007       Result := pthread_cond_destroy (T.Common.LL.CV'Access);
1008       pragma Assert (Result = 0);
1009
1010       if T.Known_Tasks_Index /= -1 then
1011          Known_Tasks (T.Known_Tasks_Index) := null;
1012       end if;
1013
1014       Free (Tmp);
1015
1016       if Is_Self then
1017          Result := st_setspecific (ATCB_Key, System.Null_Address);
1018          pragma Assert (Result = 0);
1019       end if;
1020    end Finalize_TCB;
1021
1022    ---------------
1023    -- Exit_Task --
1024    ---------------
1025
1026    procedure Exit_Task is
1027    begin
1028       Specific.Set (null);
1029    end Exit_Task;
1030
1031    ----------------
1032    -- Abort_Task --
1033    ----------------
1034
1035    procedure Abort_Task (T : Task_Id) is
1036       Result : Interfaces.C.int;
1037    begin
1038       Result :=
1039         pthread_kill
1040           (T.Common.LL.Thread,
1041            Signal (System.Interrupt_Management.Abort_Task_Interrupt));
1042       pragma Assert (Result = 0);
1043    end Abort_Task;
1044
1045    ----------------
1046    -- Initialize --
1047    ----------------
1048
1049    procedure Initialize (S : in out Suspension_Object) is
1050       Mutex_Attr : aliased pthread_mutexattr_t;
1051       Cond_Attr  : aliased pthread_condattr_t;
1052       Result     : Interfaces.C.int;
1053
1054    begin
1055       --  Initialize internal state (always to False (RM D.10(6)))
1056
1057       S.State := False;
1058       S.Waiting := False;
1059
1060       --  Initialize internal mutex
1061
1062       Result := pthread_mutexattr_init (Mutex_Attr'Access);
1063       pragma Assert (Result = 0 or else Result = ENOMEM);
1064
1065       if Result = ENOMEM then
1066          raise Storage_Error;
1067       end if;
1068
1069       Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
1070       pragma Assert (Result = 0 or else Result = ENOMEM);
1071
1072       if Result = ENOMEM then
1073          Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
1074          pragma Assert (Result = 0);
1075
1076          raise Storage_Error;
1077       end if;
1078
1079       Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
1080       pragma Assert (Result = 0);
1081
1082       --  Initialize internal condition variable
1083
1084       Result := pthread_condattr_init (Cond_Attr'Access);
1085       pragma Assert (Result = 0 or else Result = ENOMEM);
1086
1087       if Result /= 0 then
1088          Result := pthread_mutex_destroy (S.L'Access);
1089          pragma Assert (Result = 0);
1090
1091          if Result = ENOMEM then
1092             raise Storage_Error;
1093          end if;
1094       end if;
1095
1096       Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
1097       pragma Assert (Result = 0 or else Result = ENOMEM);
1098
1099       if Result /= 0 then
1100          Result := pthread_mutex_destroy (S.L'Access);
1101          pragma Assert (Result = 0);
1102
1103          if Result = ENOMEM then
1104             Result := pthread_condattr_destroy (Cond_Attr'Access);
1105             pragma Assert (Result = 0);
1106
1107             raise Storage_Error;
1108          end if;
1109       end if;
1110
1111       Result := pthread_condattr_destroy (Cond_Attr'Access);
1112       pragma Assert (Result = 0);
1113    end Initialize;
1114
1115    --------------
1116    -- Finalize --
1117    --------------
1118
1119    procedure Finalize (S : in out Suspension_Object) is
1120       Result : Interfaces.C.int;
1121
1122    begin
1123       --  Destroy internal mutex
1124
1125       Result := pthread_mutex_destroy (S.L'Access);
1126       pragma Assert (Result = 0);
1127
1128       --  Destroy internal condition variable
1129
1130       Result := pthread_cond_destroy (S.CV'Access);
1131       pragma Assert (Result = 0);
1132    end Finalize;
1133
1134    -------------------
1135    -- Current_State --
1136    -------------------
1137
1138    function Current_State (S : Suspension_Object) return Boolean is
1139    begin
1140       --  We do not want to use lock on this read operation. State is marked
1141       --  as Atomic so that we ensure that the value retrieved is correct.
1142
1143       return S.State;
1144    end Current_State;
1145
1146    ---------------
1147    -- Set_False --
1148    ---------------
1149
1150    procedure Set_False (S : in out Suspension_Object) is
1151       Result : Interfaces.C.int;
1152
1153    begin
1154       SSL.Abort_Defer.all;
1155
1156       Result := pthread_mutex_lock (S.L'Access);
1157       pragma Assert (Result = 0);
1158
1159       S.State := False;
1160
1161       Result := pthread_mutex_unlock (S.L'Access);
1162       pragma Assert (Result = 0);
1163
1164       SSL.Abort_Undefer.all;
1165    end Set_False;
1166
1167    --------------
1168    -- Set_True --
1169    --------------
1170
1171    procedure Set_True (S : in out Suspension_Object) is
1172       Result : Interfaces.C.int;
1173
1174    begin
1175       SSL.Abort_Defer.all;
1176
1177       Result := pthread_mutex_lock (S.L'Access);
1178       pragma Assert (Result = 0);
1179
1180       --  If there is already a task waiting on this suspension object then
1181       --  we resume it, leaving the state of the suspension object to False,
1182       --  as specified in (RM D.10(9)). Otherwise, just leave state set True.
1183
1184       if S.Waiting then
1185          S.Waiting := False;
1186          S.State := False;
1187
1188          Result := pthread_cond_signal (S.CV'Access);
1189          pragma Assert (Result = 0);
1190
1191       else
1192          S.State := True;
1193       end if;
1194
1195       Result := pthread_mutex_unlock (S.L'Access);
1196       pragma Assert (Result = 0);
1197
1198       SSL.Abort_Undefer.all;
1199    end Set_True;
1200
1201    ------------------------
1202    -- Suspend_Until_True --
1203    ------------------------
1204
1205    procedure Suspend_Until_True (S : in out Suspension_Object) is
1206       Result : Interfaces.C.int;
1207
1208    begin
1209       SSL.Abort_Defer.all;
1210
1211       Result := pthread_mutex_lock (S.L'Access);
1212       pragma Assert (Result = 0);
1213
1214       if S.Waiting then
1215
1216          --  Program_Error must be raised upon calling Suspend_Until_True
1217          --  if another task is already waiting on that suspension object
1218          --  (RM D.10 (10)).
1219
1220          Result := pthread_mutex_unlock (S.L'Access);
1221          pragma Assert (Result = 0);
1222
1223          SSL.Abort_Undefer.all;
1224
1225          raise Program_Error;
1226
1227       else
1228          --  Suspend the task if the state is False. Otherwise, the task
1229          --  continues its execution, and the state of the suspension object
1230          --  is set to False (RM D.10(9)).
1231
1232          if S.State then
1233             S.State := False;
1234          else
1235             S.Waiting := True;
1236             Result := pthread_cond_wait (S.CV'Access, S.L'Access);
1237          end if;
1238
1239          Result := pthread_mutex_unlock (S.L'Access);
1240          pragma Assert (Result = 0);
1241
1242          SSL.Abort_Undefer.all;
1243       end if;
1244    end Suspend_Until_True;
1245
1246    ----------------
1247    -- Check_Exit --
1248    ----------------
1249
1250    --  Dummy version
1251
1252    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1253       pragma Unreferenced (Self_ID);
1254    begin
1255       return True;
1256    end Check_Exit;
1257
1258    --------------------
1259    -- Check_No_Locks --
1260    --------------------
1261
1262    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1263       pragma Unreferenced (Self_ID);
1264    begin
1265       return True;
1266    end Check_No_Locks;
1267
1268    ----------------------
1269    -- Environment_Task --
1270    ----------------------
1271
1272    function Environment_Task return Task_Id is
1273    begin
1274       return Environment_Task_Id;
1275    end Environment_Task;
1276
1277    --------------
1278    -- Lock_RTS --
1279    --------------
1280
1281    procedure Lock_RTS is
1282    begin
1283       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1284    end Lock_RTS;
1285
1286    ----------------
1287    -- Unlock_RTS --
1288    ----------------
1289
1290    procedure Unlock_RTS is
1291    begin
1292       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1293    end Unlock_RTS;
1294
1295    ------------------
1296    -- Suspend_Task --
1297    ------------------
1298
1299    function Suspend_Task
1300      (T           : ST.Task_Id;
1301       Thread_Self : Thread_Id) return Boolean
1302    is
1303       pragma Unreferenced (T);
1304       pragma Unreferenced (Thread_Self);
1305    begin
1306       return False;
1307    end Suspend_Task;
1308
1309    -----------------
1310    -- Resume_Task --
1311    -----------------
1312
1313    function Resume_Task
1314      (T           : ST.Task_Id;
1315       Thread_Self : Thread_Id) return Boolean
1316    is
1317       pragma Unreferenced (T);
1318       pragma Unreferenced (Thread_Self);
1319    begin
1320       return False;
1321    end Resume_Task;
1322
1323    --------------------
1324    -- Stop_All_Tasks --
1325    --------------------
1326
1327    procedure Stop_All_Tasks is
1328    begin
1329       null;
1330    end Stop_All_Tasks;
1331
1332    ---------------
1333    -- Stop_Task --
1334    ---------------
1335
1336    function Stop_Task (T : ST.Task_Id) return Boolean is
1337       pragma Unreferenced (T);
1338    begin
1339       return False;
1340    end Stop_Task;
1341
1342    -------------------
1343    -- Continue_Task --
1344    -------------------
1345
1346    function Continue_Task (T : ST.Task_Id) return Boolean is
1347       pragma Unreferenced (T);
1348    begin
1349       return False;
1350    end Continue_Task;
1351
1352    ----------------
1353    -- Initialize --
1354    ----------------
1355
1356    procedure Initialize (Environment_Task : Task_Id) is
1357       act     : aliased struct_sigaction;
1358       old_act : aliased struct_sigaction;
1359       Tmp_Set : aliased sigset_t;
1360       Result  : Interfaces.C.int;
1361
1362       function State
1363         (Int  : System.Interrupt_Management.Interrupt_ID) return Character;
1364       pragma Import (C, State, "__gnat_get_interrupt_state");
1365       --  Get interrupt state.  Defined in a-init.c
1366       --  The input argument is the interrupt number,
1367       --  and the result is one of the following:
1368
1369       Default : constant Character := 's';
1370       --    'n'   this interrupt not set by any Interrupt_State pragma
1371       --    'u'   Interrupt_State pragma set state to User
1372       --    'r'   Interrupt_State pragma set state to Runtime
1373       --    's'   Interrupt_State pragma set state to System (use "default"
1374       --           system handler)
1375
1376    begin
1377       Environment_Task_Id := Environment_Task;
1378
1379       Interrupt_Management.Initialize;
1380
1381       --  Prepare the set of signals that should unblocked in all tasks
1382
1383       Result := sigemptyset (Unblocked_Signal_Mask'Access);
1384       pragma Assert (Result = 0);
1385
1386       for J in Interrupt_Management.Interrupt_ID loop
1387          if System.Interrupt_Management.Keep_Unmasked (J) then
1388             Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1389             pragma Assert (Result = 0);
1390          end if;
1391       end loop;
1392
1393       --  Initialize the lock used to synchronize chain of all ATCBs
1394
1395       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1396
1397       Specific.Initialize (Environment_Task);
1398
1399       Enter_Task (Environment_Task);
1400
1401       --  Install the abort-signal handler
1402
1403       if State
1404           (System.Interrupt_Management.Abort_Task_Interrupt) /= Default
1405       then
1406          act.sa_flags := 0;
1407          act.sa_handler := Abort_Handler'Address;
1408
1409          Result := sigemptyset (Tmp_Set'Access);
1410          pragma Assert (Result = 0);
1411          act.sa_mask := Tmp_Set;
1412
1413          Result :=
1414            sigaction
1415              (Signal (System.Interrupt_Management.Abort_Task_Interrupt),
1416               act'Unchecked_Access,
1417               old_act'Unchecked_Access);
1418
1419          pragma Assert (Result = 0);
1420       end if;
1421    end Initialize;
1422
1423 end System.Task_Primitives.Operations;