gcc-4.7-source 4.7.3-12ubuntu1 / usr / src / gcc-4.7 / debian / patches / ada-s-taprop-gnu.adb.diff

--- /dev/null	2012-01-30 20:41:15.189616186 +0100
+++ b/src/gcc/ada/s-taprop-gnu.adb	2012-04-11 19:17:52.000000000 +0200
@@ -0,0 +1,1336 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
+--                                                                          --
+--     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    --
+--                                                                          --
+--                                  B o d y                                 --
+--                                                                          --
+--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --
+--                                                                          --
+-- GNARL is free software; you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNARL was developed by the GNARL team at Florida State University.       --
+-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  This is a GNU/Hurd version of this package
+--  Note: Removed the SCHED_FIFO and Ceiling Locking from the posix version
+--  since these functions are not (yet) supported on GNU/Hurd
+
+--  This package contains all the GNULL primitives that interface directly with
+--  the underlying OS.
+
+pragma Polling (Off);
+--  Turn off polling, we do not want ATC polling to take place during tasking
+--  operations. It causes infinite loops and other problems.
+
+with Ada.Unchecked_Conversion;
+with Ada.Unchecked_Deallocation;
+
+with Interfaces.C;
+
+with System.Tasking.Debug;
+with System.Interrupt_Management;
+with System.OS_Primitives;
+with System.Task_Info;
+
+with System.Soft_Links;
+--  We use System.Soft_Links instead of System.Tasking.Initialization
+--  because the later is a higher level package that we shouldn't depend on.
+--  For example when using the restricted run time, it is replaced by
+--  System.Tasking.Restricted.Stages.
+
+package body System.Task_Primitives.Operations is
+
+   package SSL renames System.Soft_Links;
+
+   use System.Tasking.Debug;
+   use System.Tasking;
+   use Interfaces.C;
+   use System.OS_Interface;
+   use System.Parameters;
+   use System.OS_Primitives;
+
+   ----------------
+   -- Local Data --
+   ----------------
+
+   --  The followings are logically constants, but need to be initialized
+   --  at run time.
+
+   Single_RTS_Lock : aliased RTS_Lock;
+   --  This is a lock to allow only one thread of control in the RTS at
+   --  a time; it is used to execute in mutual exclusion from all other tasks.
+   --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
+
+   ATCB_Key : aliased pthread_key_t;
+   --  Key used to find the Ada Task_Id associated with a thread
+
+   Environment_Task_Id : Task_Id;
+   --  A variable to hold Task_Id for the environment task
+
+   Unblocked_Signal_Mask : aliased sigset_t;
+   --  The set of signals that should unblocked in all tasks
+
+   --  The followings are internal configuration constants needed
+
+   Next_Serial_Number : Task_Serial_Number := 100;
+   --  We start at 100, to reserve some special values for
+   --  using in error checking.
+
+   Foreign_Task_Elaborated : aliased Boolean := True;
+   --  Used to identified fake tasks (i.e., non-Ada Threads)
+
+   Use_Alternate_Stack : constant Boolean := Alternate_Stack_Size /= 0;
+   --  Whether to use an alternate signal stack for stack overflows
+
+   Abort_Handler_Installed : Boolean := False;
+   --  True if a handler for the abort signal is installed
+
+   --------------------
+   -- Local Packages --
+   --------------------
+
+   package Specific is
+
+      procedure Initialize (Environment_Task : Task_Id);
+      pragma Inline (Initialize);
+      --  Initialize various data needed by this package
+
+      function Is_Valid_Task return Boolean;
+      pragma Inline (Is_Valid_Task);
+      --  Does executing thread have a TCB?
+
+      procedure Set (Self_Id : Task_Id);
+      pragma Inline (Set);
+      --  Set the self id for the current task
+
+      function Self return Task_Id;
+      pragma Inline (Self);
+      --  Return a pointer to the Ada Task Control Block of the calling task
+
+   end Specific;
+
+   package body Specific is separate;
+   --  The body of this package is target specific
+
+   ---------------------------------
+   -- Support for foreign threads --
+   ---------------------------------
+
+   function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
+   --  Allocate and Initialize a new ATCB for the current Thread
+
+   function Register_Foreign_Thread
+     (Thread : Thread_Id) return Task_Id is separate;
+
+   -----------------------
+   -- Local Subprograms --
+   -----------------------
+
+   procedure Abort_Handler (Sig : Signal);
+   --  Signal handler used to implement asynchronous abort.
+   --  See also comment before body, below.
+
+   function To_Address is
+     new Ada.Unchecked_Conversion (Task_Id, System.Address);
+
+   -------------------
+   -- Abort_Handler --
+   -------------------
+
+   --  Target-dependent binding of inter-thread Abort signal to the raising of
+   --  the Abort_Signal exception.
+
+   --  The technical issues and alternatives here are essentially the
+   --  same as for raising exceptions in response to other signals
+   --  (e.g. Storage_Error). See code and comments in the package body
+   --  System.Interrupt_Management.
+
+   --  Some implementations may not allow an exception to be propagated out of
+   --  a handler, and others might leave the signal or interrupt that invoked
+   --  this handler masked after the exceptional return to the application
+   --  code.
+
+   --  GNAT exceptions are originally implemented using setjmp()/longjmp(). On
+   --  most UNIX systems, this will allow transfer out of a signal handler,
+   --  which is usually the only mechanism available for implementing
+   --  asynchronous handlers of this kind. However, some systems do not
+   --  restore the signal mask on longjmp(), leaving the abort signal masked.
+
+   procedure Abort_Handler (Sig : Signal) is
+      pragma Unreferenced (Sig);
+
+      T       : constant Task_Id := Self;
+      Old_Set : aliased sigset_t;
+
+      Result : Interfaces.C.int;
+      pragma Warnings (Off, Result);
+
+   begin
+      --  It's not safe to raise an exception when using GCC ZCX mechanism.
+      --  Note that we still need to install a signal handler, since in some
+      --  cases (e.g. shutdown of the Server_Task in System.Interrupts) we
+      --  need to send the Abort signal to a task.
+
+      if ZCX_By_Default and then GCC_ZCX_Support then
+         return;
+      end if;
+
+      if T.Deferral_Level = 0
+        and then T.Pending_ATC_Level < T.ATC_Nesting_Level and then
+        not T.Aborting
+      then
+         T.Aborting := True;
+
+         --  Make sure signals used for RTS internal purpose are unmasked
+
+         Result := pthread_sigmask (SIG_UNBLOCK,
+           Unblocked_Signal_Mask'Access, Old_Set'Access);
+         pragma Assert (Result = 0);
+
+         raise Standard'Abort_Signal;
+      end if;
+   end Abort_Handler;
+
+   -----------------
+   -- Stack_Guard --
+   -----------------
+
+   procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
+      Stack_Base : constant Address := Get_Stack_Base (T.Common.LL.Thread);
+      Guard_Page_Address : Address;
+
+      Res : Interfaces.C.int;
+
+   begin
+      if Stack_Base_Available then
+
+         --  Compute the guard page address
+
+         Guard_Page_Address :=
+           Stack_Base - (Stack_Base mod Get_Page_Size) + Get_Page_Size;
+
+         Res :=
+           mprotect (Guard_Page_Address, Get_Page_Size,
+                     prot => (if On then PROT_ON else PROT_OFF));
+         pragma Assert (Res = 0);
+      end if;
+   end Stack_Guard;
+
+   --------------------
+   -- Get_Thread_Id  --
+   --------------------
+
+   function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
+   begin
+      return T.Common.LL.Thread;
+   end Get_Thread_Id;
+
+   ----------
+   -- Self --
+   ----------
+
+   function Self return Task_Id renames Specific.Self;
+
+   ---------------------
+   -- Initialize_Lock --
+   ---------------------
+
+   --  Note: mutexes and cond_variables needed per-task basis are
+   --        initialized in Initialize_TCB and the Storage_Error is
+   --        handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
+   --        used in RTS is initialized before any status change of RTS.
+   --        Therefore raising Storage_Error in the following routines
+   --        should be able to be handled safely.
+
+   procedure Initialize_Lock
+     (Prio : System.Any_Priority;
+      L    : not null access Lock)
+   is
+      pragma Unreferenced (Prio);
+
+      Attributes : aliased pthread_mutexattr_t;
+      Result     : Interfaces.C.int;
+
+   begin
+      Result := pthread_mutexattr_init (Attributes'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         raise Storage_Error with "Failed to allocate a lock";
+      end if;
+
+      Result := pthread_mutex_init (L, Attributes'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         Result := pthread_mutexattr_destroy (Attributes'Access);
+         raise Storage_Error;
+      end if;
+
+      Result := pthread_mutexattr_destroy (Attributes'Access);
+      pragma Assert (Result = 0);
+   end Initialize_Lock;
+
+   procedure Initialize_Lock
+     (L : not null access RTS_Lock; Level : Lock_Level)
+   is
+      pragma Unreferenced (Level);
+
+      Attributes : aliased pthread_mutexattr_t;
+      Result     : Interfaces.C.int;
+
+   begin
+      Result := pthread_mutexattr_init (Attributes'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         raise Storage_Error with "Failed to allocate a lock";
+      end if;
+
+      Result := pthread_mutex_init (L, Attributes'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         Result := pthread_mutexattr_destroy (Attributes'Access);
+         raise Storage_Error;
+      end if;
+
+      Result := pthread_mutexattr_destroy (Attributes'Access);
+      pragma Assert (Result = 0);
+   end Initialize_Lock;
+
+   -------------------
+   -- Finalize_Lock --
+   -------------------
+
+   procedure Finalize_Lock (L : not null access Lock) is
+      Result : Interfaces.C.int;
+   begin
+      Result := pthread_mutex_destroy (L);
+      pragma Assert (Result = 0);
+   end Finalize_Lock;
+
+   procedure Finalize_Lock (L : not null access RTS_Lock) is
+      Result : Interfaces.C.int;
+   begin
+      Result := pthread_mutex_destroy (L);
+      pragma Assert (Result = 0);
+   end Finalize_Lock;
+
+   ----------------
+   -- Write_Lock --
+   ----------------
+
+   procedure Write_Lock
+     (L : not null access Lock; Ceiling_Violation : out Boolean)
+   is
+      Result : Interfaces.C.int;
+
+   begin
+      Result := pthread_mutex_lock (L);
+
+      --  Assume that the cause of EINVAL is a priority ceiling violation
+
+      Ceiling_Violation := (Result = EINVAL);
+      pragma Assert (Result = 0 or else Result = EINVAL);
+   end Write_Lock;
+
+   procedure Write_Lock
+     (L           : not null access RTS_Lock;
+      Global_Lock : Boolean := False)
+   is
+      Result : Interfaces.C.int;
+   begin
+      if not Single_Lock or else Global_Lock then
+         Result := pthread_mutex_lock (L);
+         pragma Assert (Result = 0);
+      end if;
+   end Write_Lock;
+
+   procedure Write_Lock (T : Task_Id) is
+      Result : Interfaces.C.int;
+   begin
+      if not Single_Lock then
+         Result := pthread_mutex_lock (T.Common.LL.L'Access);
+         pragma Assert (Result = 0);
+      end if;
+   end Write_Lock;
+
+   ---------------
+   -- Read_Lock --
+   ---------------
+
+   procedure Read_Lock
+     (L : not null access Lock; Ceiling_Violation : out Boolean) is
+   begin
+      Write_Lock (L, Ceiling_Violation);
+   end Read_Lock;
+
+   ------------
+   -- Unlock --
+   ------------
+
+   procedure Unlock (L : not null access Lock) is
+      Result : Interfaces.C.int;
+   begin
+      Result := pthread_mutex_unlock (L);
+      pragma Assert (Result = 0);
+   end Unlock;
+
+   procedure Unlock
+     (L : not null access RTS_Lock; Global_Lock : Boolean := False)
+   is
+      Result : Interfaces.C.int;
+   begin
+      if not Single_Lock or else Global_Lock then
+         Result := pthread_mutex_unlock (L);
+         pragma Assert (Result = 0);
+      end if;
+   end Unlock;
+
+   procedure Unlock (T : Task_Id) is
+      Result : Interfaces.C.int;
+   begin
+      if not Single_Lock then
+         Result := pthread_mutex_unlock (T.Common.LL.L'Access);
+         pragma Assert (Result = 0);
+      end if;
+   end Unlock;
+
+   -----------------
+   -- Set_Ceiling --
+   -----------------
+
+   --  Dynamic priority ceilings are not supported by the underlying system
+
+   procedure Set_Ceiling
+     (L    : not null access Lock;
+      Prio : System.Any_Priority)
+   is
+      pragma Unreferenced (L, Prio);
+   begin
+      null;
+   end Set_Ceiling;
+
+   -----------
+   -- Sleep --
+   -----------
+
+   procedure Sleep
+     (Self_ID : Task_Id;
+      Reason  : System.Tasking.Task_States)
+   is
+      pragma Unreferenced (Reason);
+
+      Result : Interfaces.C.int;
+
+   begin
+      Result :=
+        pthread_cond_wait
+          (cond  => Self_ID.Common.LL.CV'Access,
+           mutex => (if Single_Lock
+                     then Single_RTS_Lock'Access
+                     else Self_ID.Common.LL.L'Access));
+
+      --  EINTR is not considered a failure
+
+      pragma Assert (Result = 0 or else Result = EINTR);
+   end Sleep;
+
+   -----------------
+   -- Timed_Sleep --
+   -----------------
+
+   --  This is for use within the run-time system, so abort is
+   --  assumed to be already deferred, and the caller should be
+   --  holding its own ATCB lock.
+
+   procedure Timed_Sleep
+     (Self_ID  : Task_Id;
+      Time     : Duration;
+      Mode     : ST.Delay_Modes;
+      Reason   : Task_States;
+      Timedout : out Boolean;
+      Yielded  : out Boolean)
+   is
+      pragma Unreferenced (Reason);
+
+      Base_Time  : constant Duration := Monotonic_Clock;
+      Check_Time : Duration := Base_Time;
+      Rel_Time   : Duration;
+      Abs_Time   : Duration;
+      Request    : aliased timespec;
+      Result     : Interfaces.C.int;
+
+   begin
+      Timedout := True;
+      Yielded := False;
+
+      if Mode = Relative then
+         Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
+
+         if Relative_Timed_Wait then
+            Rel_Time := Duration'Min (Max_Sensible_Delay, Time);
+         end if;
+
+      else
+         Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
+
+         if Relative_Timed_Wait then
+            Rel_Time := Duration'Min (Max_Sensible_Delay, Time - Check_Time);
+         end if;
+      end if;
+
+      if Abs_Time > Check_Time then
+         Request :=
+           To_Timespec (if Relative_Timed_Wait then Rel_Time else Abs_Time);
+
+         loop
+            exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
+
+            Result :=
+              pthread_cond_timedwait
+                (cond    => Self_ID.Common.LL.CV'Access,
+                 mutex   => (if Single_Lock
+                             then Single_RTS_Lock'Access
+                             else Self_ID.Common.LL.L'Access),
+                 abstime => Request'Access);
+
+            Check_Time := Monotonic_Clock;
+            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
+
+            if Result = 0 or Result = EINTR then
+
+               --  Somebody may have called Wakeup for us
+
+               Timedout := False;
+               exit;
+            end if;
+
+            pragma Assert (Result = ETIMEDOUT);
+         end loop;
+      end if;
+   end Timed_Sleep;
+
+   -----------------
+   -- Timed_Delay --
+   -----------------
+
+   --  This is for use in implementing delay statements, so we assume the
+   --  caller is abort-deferred but is holding no locks.
+
+   procedure Timed_Delay
+     (Self_ID : Task_Id;
+      Time    : Duration;
+      Mode    : ST.Delay_Modes)
+   is
+      Base_Time  : constant Duration := Monotonic_Clock;
+      Check_Time : Duration := Base_Time;
+      Abs_Time   : Duration;
+      Rel_Time   : Duration;
+      Request    : aliased timespec;
+
+      Result : Interfaces.C.int;
+      pragma Warnings (Off, Result);
+
+   begin
+      if Single_Lock then
+         Lock_RTS;
+      end if;
+
+      Write_Lock (Self_ID);
+
+      if Mode = Relative then
+         Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
+
+         if Relative_Timed_Wait then
+            Rel_Time := Duration'Min (Max_Sensible_Delay, Time);
+         end if;
+
+      else
+         Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
+
+         if Relative_Timed_Wait then
+            Rel_Time := Duration'Min (Max_Sensible_Delay, Time - Check_Time);
+         end if;
+      end if;
+
+      if Abs_Time > Check_Time then
+         Request :=
+           To_Timespec (if Relative_Timed_Wait then Rel_Time else Abs_Time);
+         Self_ID.Common.State := Delay_Sleep;
+
+         loop
+            exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
+
+            Result :=
+              pthread_cond_timedwait
+                (cond    => Self_ID.Common.LL.CV'Access,
+                 mutex   => (if Single_Lock
+                             then Single_RTS_Lock'Access
+                             else Self_ID.Common.LL.L'Access),
+                 abstime => Request'Access);
+
+            Check_Time := Monotonic_Clock;
+            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
+
+            pragma Assert (Result = 0
+                             or else Result = ETIMEDOUT
+                             or else Result = EINTR);
+         end loop;
+
+         Self_ID.Common.State := Runnable;
+      end if;
+
+      Unlock (Self_ID);
+
+      if Single_Lock then
+         Unlock_RTS;
+      end if;
+
+      Result := sched_yield;
+   end Timed_Delay;
+
+   ---------------------
+   -- Monotonic_Clock --
+   ---------------------
+
+   function Monotonic_Clock return Duration is
+      TS     : aliased timespec;
+      Result : Interfaces.C.int;
+   begin
+      Result := clock_gettime
+        (clock_id => CLOCK_REALTIME, tp => TS'Unchecked_Access);
+      pragma Assert (Result = 0);
+      return To_Duration (TS);
+   end Monotonic_Clock;
+
+   -------------------
+   -- RT_Resolution --
+   -------------------
+
+   function RT_Resolution return Duration is
+   begin
+      return 10#1.0#E-6;
+   end RT_Resolution;
+
+   ------------
+   -- Wakeup --
+   ------------
+
+   procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
+      pragma Unreferenced (Reason);
+      Result : Interfaces.C.int;
+   begin
+      Result := pthread_cond_signal (T.Common.LL.CV'Access);
+      pragma Assert (Result = 0);
+   end Wakeup;
+
+   -----------
+   -- Yield --
+   -----------
+
+   procedure Yield (Do_Yield : Boolean := True) is
+      Result : Interfaces.C.int;
+      pragma Unreferenced (Result);
+   begin
+      if Do_Yield then
+         Result := sched_yield;
+      end if;
+   end Yield;
+
+   ------------------
+   -- Set_Priority --
+   ------------------
+
+   procedure Set_Priority
+     (T                   : Task_Id;
+      Prio                : System.Any_Priority;
+      Loss_Of_Inheritance : Boolean := False)
+   is
+      pragma Unreferenced (Loss_Of_Inheritance);
+
+   begin
+      null;
+   end Set_Priority;
+
+   ------------------
+   -- Get_Priority --
+   ------------------
+
+   function Get_Priority (T : Task_Id) return System.Any_Priority is
+   begin
+      return T.Common.Current_Priority;
+   end Get_Priority;
+
+   ----------------
+   -- Enter_Task --
+   ----------------
+
+   procedure Enter_Task (Self_ID : Task_Id) is
+   begin
+      Self_ID.Common.LL.Thread := pthread_self;
+      Self_ID.Common.LL.LWP := lwp_self;
+
+      Specific.Set (Self_ID);
+
+      if Use_Alternate_Stack then
+         declare
+            Stack  : aliased stack_t;
+            Result : Interfaces.C.int;
+         begin
+            Stack.ss_sp    := Self_ID.Common.Task_Alternate_Stack;
+            Stack.ss_size  := Alternate_Stack_Size;
+            Stack.ss_flags := 0;
+            Result := sigaltstack (Stack'Access, null);
+            pragma Assert (Result = 0);
+         end;
+      end if;
+   end Enter_Task;
+
+   --------------
+   -- New_ATCB --
+   --------------
+
+   function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
+   begin
+      return new Ada_Task_Control_Block (Entry_Num);
+   end New_ATCB;
+
+   -------------------
+   -- Is_Valid_Task --
+   -------------------
+
+   function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
+
+   -----------------------------
+   -- Register_Foreign_Thread --
+   -----------------------------
+
+   function Register_Foreign_Thread return Task_Id is
+   begin
+      if Is_Valid_Task then
+         return Self;
+      else
+         return Register_Foreign_Thread (pthread_self);
+      end if;
+   end Register_Foreign_Thread;
+
+   --------------------
+   -- Initialize_TCB --
+   --------------------
+
+   procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
+      Mutex_Attr : aliased pthread_mutexattr_t;
+      Result     : Interfaces.C.int;
+      Cond_Attr  : aliased pthread_condattr_t;
+
+   begin
+      --  Give the task a unique serial number
+
+      Self_ID.Serial_Number := Next_Serial_Number;
+      Next_Serial_Number := Next_Serial_Number + 1;
+      pragma Assert (Next_Serial_Number /= 0);
+
+      if not Single_Lock then
+         Result := pthread_mutexattr_init (Mutex_Attr'Access);
+         pragma Assert (Result = 0 or else Result = ENOMEM);
+
+         if Result = 0 then
+            Result :=
+              pthread_mutex_init
+                (Self_ID.Common.LL.L'Access,
+                 Mutex_Attr'Access);
+            pragma Assert (Result = 0 or else Result = ENOMEM);
+         end if;
+
+         if Result /= 0 then
+            Succeeded := False;
+            return;
+         end if;
+
+         Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
+         pragma Assert (Result = 0);
+      end if;
+
+      Result := pthread_condattr_init (Cond_Attr'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = 0 then
+         Result :=
+           pthread_cond_init
+             (Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
+         pragma Assert (Result = 0 or else Result = ENOMEM);
+      end if;
+
+      if Result = 0 then
+         Succeeded := True;
+      else
+         if not Single_Lock then
+            Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
+            pragma Assert (Result = 0);
+         end if;
+
+         Succeeded := False;
+      end if;
+
+      Result := pthread_condattr_destroy (Cond_Attr'Access);
+      pragma Assert (Result = 0);
+   end Initialize_TCB;
+
+   -----------------
+   -- Create_Task --
+   -----------------
+
+   procedure Create_Task
+     (T          : Task_Id;
+      Wrapper    : System.Address;
+      Stack_Size : System.Parameters.Size_Type;
+      Priority   : System.Any_Priority;
+      Succeeded  : out Boolean)
+   is
+      Attributes          : aliased pthread_attr_t;
+      Adjusted_Stack_Size : Interfaces.C.size_t;
+      Page_Size           : constant Interfaces.C.size_t := Get_Page_Size;
+      Result              : Interfaces.C.int;
+
+      function Thread_Body_Access is new
+        Ada.Unchecked_Conversion (System.Address, Thread_Body);
+
+      use System.Task_Info;
+
+   begin
+      Adjusted_Stack_Size :=
+         Interfaces.C.size_t (Stack_Size + Alternate_Stack_Size);
+
+      if Stack_Base_Available then
+
+         --  If Stack Checking is supported then allocate 2 additional pages:
+
+         --  In the worst case, stack is allocated at something like
+         --  N * Get_Page_Size - epsilon, we need to add the size for 2 pages
+         --  to be sure the effective stack size is greater than what
+         --  has been asked.
+
+         Adjusted_Stack_Size := Adjusted_Stack_Size + 2 * Page_Size;
+      end if;
+
+      --  Round stack size as this is required by some OSes (Darwin)
+
+      Adjusted_Stack_Size := Adjusted_Stack_Size + Page_Size - 1;
+      Adjusted_Stack_Size :=
+        Adjusted_Stack_Size - Adjusted_Stack_Size mod Page_Size;
+
+      Result := pthread_attr_init (Attributes'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result /= 0 then
+         Succeeded := False;
+         return;
+      end if;
+
+      Result :=
+        pthread_attr_setdetachstate
+          (Attributes'Access, PTHREAD_CREATE_DETACHED);
+      pragma Assert (Result = 0);
+
+      Result :=
+        pthread_attr_setstacksize
+          (Attributes'Access, Adjusted_Stack_Size);
+      pragma Assert (Result = 0);
+
+      --  Since the initial signal mask of a thread is inherited from the
+      --  creator, and the Environment task has all its signals masked, we
+      --  do not need to manipulate caller's signal mask at this point.
+      --  All tasks in RTS will have All_Tasks_Mask initially.
+
+      Result := pthread_create
+        (T.Common.LL.Thread'Access,
+         Attributes'Access,
+         Thread_Body_Access (Wrapper),
+         To_Address (T));
+      pragma Assert (Result = 0 or else Result = EAGAIN);
+
+      Succeeded := Result = 0;
+
+      Result := pthread_attr_destroy (Attributes'Access);
+      pragma Assert (Result = 0);
+
+      if Succeeded then
+         Set_Priority (T, Priority);
+      end if;
+   end Create_Task;
+
+   ------------------
+   -- Finalize_TCB --
+   ------------------
+
+   procedure Finalize_TCB (T : Task_Id) is
+      Result  : Interfaces.C.int;
+      Tmp     : Task_Id := T;
+      Is_Self : constant Boolean := T = Self;
+
+      procedure Free is new
+        Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
+
+   begin
+      if not Single_Lock then
+         Result := pthread_mutex_destroy (T.Common.LL.L'Access);
+         pragma Assert (Result = 0);
+      end if;
+
+      Result := pthread_cond_destroy (T.Common.LL.CV'Access);
+      pragma Assert (Result = 0);
+
+      if T.Known_Tasks_Index /= -1 then
+         Known_Tasks (T.Known_Tasks_Index) := null;
+      end if;
+
+      Free (Tmp);
+
+      if Is_Self then
+         Specific.Set (null);
+      end if;
+   end Finalize_TCB;
+
+   ---------------
+   -- Exit_Task --
+   ---------------
+
+   procedure Exit_Task is
+   begin
+      --  Mark this task as unknown, so that if Self is called, it won't
+      --  return a dangling pointer.
+
+      Specific.Set (null);
+   end Exit_Task;
+
+   ----------------
+   -- Abort_Task --
+   ----------------
+
+   procedure Abort_Task (T : Task_Id) is
+      Result : Interfaces.C.int;
+   begin
+      if Abort_Handler_Installed then
+         Result :=
+           pthread_kill
+             (T.Common.LL.Thread,
+              Signal (System.Interrupt_Management.Abort_Task_Interrupt));
+         pragma Assert (Result = 0);
+      end if;
+   end Abort_Task;
+
+   ----------------
+   -- Initialize --
+   ----------------
+
+   procedure Initialize (S : in out Suspension_Object) is
+      Mutex_Attr : aliased pthread_mutexattr_t;
+      Cond_Attr  : aliased pthread_condattr_t;
+      Result     : Interfaces.C.int;
+
+   begin
+      --  Initialize internal state (always to False (RM D.10 (6)))
+
+      S.State := False;
+      S.Waiting := False;
+
+      --  Initialize internal mutex
+
+      Result := pthread_mutexattr_init (Mutex_Attr'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         raise Storage_Error;
+      end if;
+
+      Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result = ENOMEM then
+         Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
+         pragma Assert (Result = 0);
+
+         raise Storage_Error;
+      end if;
+
+      Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
+      pragma Assert (Result = 0);
+
+      --  Initialize internal condition variable
+
+      Result := pthread_condattr_init (Cond_Attr'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result /= 0 then
+         Result := pthread_mutex_destroy (S.L'Access);
+         pragma Assert (Result = 0);
+
+         if Result = ENOMEM then
+            raise Storage_Error;
+         end if;
+      end if;
+
+      Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
+      pragma Assert (Result = 0 or else Result = ENOMEM);
+
+      if Result /= 0 then
+         Result := pthread_mutex_destroy (S.L'Access);
+         pragma Assert (Result = 0);
+
+         if Result = ENOMEM then
+            Result := pthread_condattr_destroy (Cond_Attr'Access);
+            pragma Assert (Result = 0);
+            raise Storage_Error;
+         end if;
+      end if;
+
+      Result := pthread_condattr_destroy (Cond_Attr'Access);
+      pragma Assert (Result = 0);
+   end Initialize;
+
+   --------------
+   -- Finalize --
+   --------------
+
+   procedure Finalize (S : in out Suspension_Object) is
+      Result : Interfaces.C.int;
+
+   begin
+      --  Destroy internal mutex
+
+      Result := pthread_mutex_destroy (S.L'Access);
+      pragma Assert (Result = 0);
+
+      --  Destroy internal condition variable
+
+      Result := pthread_cond_destroy (S.CV'Access);
+      pragma Assert (Result = 0);
+   end Finalize;
+
+   -------------------
+   -- Current_State --
+   -------------------
+
+   function Current_State (S : Suspension_Object) return Boolean is
+   begin
+      --  We do not want to use lock on this read operation. State is marked
+      --  as Atomic so that we ensure that the value retrieved is correct.
+
+      return S.State;
+   end Current_State;
+
+   ---------------
+   -- Set_False --
+   ---------------
+
+   procedure Set_False (S : in out Suspension_Object) is
+      Result : Interfaces.C.int;
+
+   begin
+      SSL.Abort_Defer.all;
+
+      Result := pthread_mutex_lock (S.L'Access);
+      pragma Assert (Result = 0);
+
+      S.State := False;
+
+      Result := pthread_mutex_unlock (S.L'Access);
+      pragma Assert (Result = 0);
+
+      SSL.Abort_Undefer.all;
+   end Set_False;
+
+   --------------
+   -- Set_True --
+   --------------
+
+   procedure Set_True (S : in out Suspension_Object) is
+      Result : Interfaces.C.int;
+
+   begin
+      SSL.Abort_Defer.all;
+
+      Result := pthread_mutex_lock (S.L'Access);
+      pragma Assert (Result = 0);
+
+      --  If there is already a task waiting on this suspension object then
+      --  we resume it, leaving the state of the suspension object to False,
+      --  as it is specified in (RM D.10(9)). Otherwise, it just leaves
+      --  the state to True.
+
+      if S.Waiting then
+         S.Waiting := False;
+         S.State := False;
+
+         Result := pthread_cond_signal (S.CV'Access);
+         pragma Assert (Result = 0);
+
+      else
+         S.State := True;
+      end if;
+
+      Result := pthread_mutex_unlock (S.L'Access);
+      pragma Assert (Result = 0);
+
+      SSL.Abort_Undefer.all;
+   end Set_True;
+
+   ------------------------
+   -- Suspend_Until_True --
+   ------------------------
+
+   procedure Suspend_Until_True (S : in out Suspension_Object) is
+      Result : Interfaces.C.int;
+
+   begin
+      SSL.Abort_Defer.all;
+
+      Result := pthread_mutex_lock (S.L'Access);
+      pragma Assert (Result = 0);
+
+      if S.Waiting then
+
+         --  Program_Error must be raised upon calling Suspend_Until_True
+         --  if another task is already waiting on that suspension object
+         --  (RM D.10(10)).
+
+         Result := pthread_mutex_unlock (S.L'Access);
+         pragma Assert (Result = 0);
+
+         SSL.Abort_Undefer.all;
+
+         raise Program_Error;
+
+      else
+         --  Suspend the task if the state is False. Otherwise, the task
+         --  continues its execution, and the state of the suspension object
+         --  is set to False (ARM D.10 par. 9).
+
+         if S.State then
+            S.State := False;
+         else
+            S.Waiting := True;
+
+            loop
+               --  Loop in case pthread_cond_wait returns earlier than expected
+               --  (e.g. in case of EINTR caused by a signal).
+
+               Result := pthread_cond_wait (S.CV'Access, S.L'Access);
+               pragma Assert (Result = 0 or else Result = EINTR);
+
+               exit when not S.Waiting;
+            end loop;
+         end if;
+
+         Result := pthread_mutex_unlock (S.L'Access);
+         pragma Assert (Result = 0);
+
+         SSL.Abort_Undefer.all;
+      end if;
+   end Suspend_Until_True;
+
+   ----------------
+   -- Check_Exit --
+   ----------------
+
+   --  Dummy version
+
+   function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
+      pragma Unreferenced (Self_ID);
+   begin
+      return True;
+   end Check_Exit;
+
+   --------------------
+   -- Check_No_Locks --
+   --------------------
+
+   function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
+      pragma Unreferenced (Self_ID);
+   begin
+      return True;
+   end Check_No_Locks;
+
+   ----------------------
+   -- Environment_Task --
+   ----------------------
+
+   function Environment_Task return Task_Id is
+   begin
+      return Environment_Task_Id;
+   end Environment_Task;
+
+   --------------
+   -- Lock_RTS --
+   --------------
+
+   procedure Lock_RTS is
+   begin
+      Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
+   end Lock_RTS;
+
+   ----------------
+   -- Unlock_RTS --
+   ----------------
+
+   procedure Unlock_RTS is
+   begin
+      Unlock (Single_RTS_Lock'Access, Global_Lock => True);
+   end Unlock_RTS;
+
+   ------------------
+   -- Suspend_Task --
+   ------------------
+
+   function Suspend_Task
+     (T           : ST.Task_Id;
+      Thread_Self : Thread_Id) return Boolean
+   is
+      pragma Unreferenced (T, Thread_Self);
+   begin
+      return False;
+   end Suspend_Task;
+
+   -----------------
+   -- Resume_Task --
+   -----------------
+
+   function Resume_Task
+     (T           : ST.Task_Id;
+      Thread_Self : Thread_Id) return Boolean
+   is
+      pragma Unreferenced (T, Thread_Self);
+   begin
+      return False;
+   end Resume_Task;
+
+   --------------------
+   -- Stop_All_Tasks --
+   --------------------
+
+   procedure Stop_All_Tasks is
+   begin
+      null;
+   end Stop_All_Tasks;
+
+   ---------------
+   -- Stop_Task --
+   ---------------
+
+   function Stop_Task (T : ST.Task_Id) return Boolean is
+      pragma Unreferenced (T);
+   begin
+      return False;
+   end Stop_Task;
+
+   -------------------
+   -- Continue_Task --
+   -------------------
+
+   function Continue_Task (T : ST.Task_Id) return Boolean is
+      pragma Unreferenced (T);
+   begin
+      return False;
+   end Continue_Task;
+
+   ----------------
+   -- Initialize --
+   ----------------
+
+   procedure Initialize (Environment_Task : Task_Id) is
+      act     : aliased struct_sigaction;
+      old_act : aliased struct_sigaction;
+      Tmp_Set : aliased sigset_t;
+      Result  : Interfaces.C.int;
+
+      function State
+        (Int : System.Interrupt_Management.Interrupt_ID) return Character;
+      pragma Import (C, State, "__gnat_get_interrupt_state");
+      --  Get interrupt state.  Defined in a-init.c
+      --  The input argument is the interrupt number,
+      --  and the result is one of the following:
+
+      Default : constant Character := 's';
+      --    'n'   this interrupt not set by any Interrupt_State pragma
+      --    'u'   Interrupt_State pragma set state to User
+      --    'r'   Interrupt_State pragma set state to Runtime
+      --    's'   Interrupt_State pragma set state to System (use "default"
+      --           system handler)
+
+   begin
+      Environment_Task_Id := Environment_Task;
+
+      Interrupt_Management.Initialize;
+
+      --  Prepare the set of signals that should unblocked in all tasks
+
+      Result := sigemptyset (Unblocked_Signal_Mask'Access);
+      pragma Assert (Result = 0);
+
+      for J in Interrupt_Management.Interrupt_ID loop
+         if System.Interrupt_Management.Keep_Unmasked (J) then
+            Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
+            pragma Assert (Result = 0);
+         end if;
+      end loop;
+
+      --  Initialize the lock used to synchronize chain of all ATCBs
+
+      Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
+
+      Specific.Initialize (Environment_Task);
+
+      if Use_Alternate_Stack then
+         Environment_Task.Common.Task_Alternate_Stack :=
+           Alternate_Stack'Address;
+      end if;
+
+      --  Make environment task known here because it doesn't go through
+      --  Activate_Tasks, which does it for all other tasks.
+
+      Known_Tasks (Known_Tasks'First) := Environment_Task;
+      Environment_Task.Known_Tasks_Index := Known_Tasks'First;
+
+      Enter_Task (Environment_Task);
+
+      if State
+          (System.Interrupt_Management.Abort_Task_Interrupt) /= Default
+      then
+         act.sa_flags := 0;
+         act.sa_handler := Abort_Handler'Address;
+
+         Result := sigemptyset (Tmp_Set'Access);
+         pragma Assert (Result = 0);
+         act.sa_mask := Tmp_Set;
+
+         Result :=
+           sigaction
+             (Signal (System.Interrupt_Management.Abort_Task_Interrupt),
+              act'Unchecked_Access,
+              old_act'Unchecked_Access);
+         pragma Assert (Result = 0);
+         Abort_Handler_Installed := True;
+      end if;
+   end Initialize;
+
+end System.Task_Primitives.Operations;