------------------------------------------------------------------------------ -- -- -- GNU ADA 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) 1992-2002, 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 2, or (at your option) any later ver- -- -- sion. GNARL 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. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNARL; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a Solaris (native) version of this package -- 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 System.Tasking.Debug; -- used for Known_Tasks with Ada.Exceptions; -- used for Raise_Exception with GNAT.OS_Lib; -- used for String_Access, Getenv with Interfaces.C; -- used for int -- size_t with System.Interrupt_Management; -- used for Keep_Unmasked -- Abort_Task_Interrupt -- Interrupt_ID with System.Interrupt_Management.Operations; -- used for Set_Interrupt_Mask -- All_Tasks_Mask pragma Elaborate_All (System.Interrupt_Management.Operations); with System.Parameters; -- used for Size_Type with System.Tasking; -- used for Ada_Task_Control_Block -- Task_ID -- ATCB components and types with System.Task_Info; -- to initialize Task_Info for a C thread, in function Self with System.Soft_Links; -- used for Defer/Undefer_Abort -- to initialize TSD for a C thread, in function Self -- Note that we do not use System.Tasking.Initialization directly since -- this 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.Initialization with System.OS_Primitives; -- used for Delay_Modes with Unchecked_Conversion; with Unchecked_Deallocation; package body System.Task_Primitives.Operations is use System.Tasking.Debug; use System.Tasking; use Interfaces.C; use System.OS_Interface; use System.Parameters; use Ada.Exceptions; use System.OS_Primitives; package SSL renames System.Soft_Links; ------------------ -- Local Data -- ------------------ -- The following are logically constants, but need to be initialized -- at run time. Environment_Task_ID : Task_ID; -- A variable to hold Task_ID for the environment task. -- If we use this variable to get the Task_ID, we need the following -- ATCB_Key only for non-Ada threads. Unblocked_Signal_Mask : aliased sigset_t; -- The set of signals that should unblocked in all tasks ATCB_Key : aliased thread_key_t; -- Key used to find the Ada Task_ID associated with a thread, -- at least for C threads unknown to the Ada run-time system. 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 Next_Serial_Number : Task_Serial_Number := 100; -- We start at 100, to reserve some special values for -- using in error checking. -- The following are internal configuration constants needed. ------------------------ -- Priority Support -- ------------------------ Priority_Ceiling_Emulation : constant Boolean := True; -- controls whether we emulate priority ceiling locking -- To get a scheduling close to annex D requirements, we use the real-time -- class provided for LWP's and map each task/thread to a specific and -- unique LWP (there is 1 thread per LWP, and 1 LWP per thread). -- The real time class can only be set when the process has root -- priviledges, so in the other cases, we use the normal thread scheduling -- and priority handling. Using_Real_Time_Class : Boolean := False; -- indicates wether the real time class is being used (i.e the process -- has root priviledges). Prio_Param : aliased struct_pcparms; -- Hold priority info (Real_Time) initialized during the package -- elaboration. ------------------------------------- -- External Configuration Values -- ------------------------------------- Time_Slice_Val : Interfaces.C.long; pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); Dispatching_Policy : Character; pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy"); -------------------------------- -- Foreign Threads Detection -- -------------------------------- -- The following are used to allow the Self function to -- automatically generate ATCB's for C threads that happen to call -- Ada procedure, which in turn happen to call the Ada run-time system. type Fake_ATCB; type Fake_ATCB_Ptr is access Fake_ATCB; type Fake_ATCB is record Stack_Base : Interfaces.C.unsigned := 0; -- A value of zero indicates the node is not in use. Next : Fake_ATCB_Ptr; Real_ATCB : aliased Ada_Task_Control_Block (0); end record; Fake_ATCB_List : Fake_ATCB_Ptr; -- A linear linked list. -- The list is protected by Single_RTS_Lock; -- Nodes are added to this list from the front. -- Once a node is added to this list, it is never removed. Fake_Task_Elaborated : aliased Boolean := True; -- Used to identified fake tasks (i.e., non-Ada Threads). Next_Fake_ATCB : Fake_ATCB_Ptr; -- Used to allocate one Fake_ATCB in advance. See comment in New_Fake_ATCB ------------ -- Checks -- ------------ Check_Count : Integer := 0; Old_Owner : Task_ID; Lock_Count : Integer := 0; Unlock_Count : Integer := 0; function To_Lock_Ptr is new Unchecked_Conversion (RTS_Lock_Ptr, Lock_Ptr); function To_Task_ID is new Unchecked_Conversion (Owner_ID, Task_ID); function To_Owner_ID is new Unchecked_Conversion (Task_ID, Owner_ID); ----------------------- -- Local Subprograms -- ----------------------- function sysconf (name : System.OS_Interface.int) return processorid_t; pragma Import (C, sysconf, "sysconf"); SC_NPROCESSORS_CONF : constant System.OS_Interface.int := 14; function Num_Procs (name : System.OS_Interface.int := SC_NPROCESSORS_CONF) return processorid_t renames sysconf; procedure Abort_Handler (Sig : Signal; Code : access siginfo_t; Context : access ucontext_t); function To_thread_t is new Unchecked_Conversion (Integer, System.OS_Interface.thread_t); function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID); function To_Address is new Unchecked_Conversion (Task_ID, System.Address); function Thread_Body_Access is new Unchecked_Conversion (System.Address, Thread_Body); function New_Fake_ATCB (Stack_Base : Interfaces.C.unsigned) return Task_ID; -- Allocate and Initialize a new ATCB. This code can safely be called from -- a foreign thread, as it doesn't access implicitly or explicitly -- "self" before having initialized the new ATCB. pragma Warnings (Off, New_Fake_ATCB); -- Disable warning on this function, since the Solaris x86 version does -- not use it. ------------ -- Checks -- ------------ function Check_Initialize_Lock (L : Lock_Ptr; Level : Lock_Level) return Boolean; pragma Inline (Check_Initialize_Lock); function Check_Lock (L : Lock_Ptr) return Boolean; pragma Inline (Check_Lock); function Record_Lock (L : Lock_Ptr) return Boolean; pragma Inline (Record_Lock); function Check_Sleep (Reason : Task_States) return Boolean; pragma Inline (Check_Sleep); function Record_Wakeup (L : Lock_Ptr; Reason : Task_States) return Boolean; pragma Inline (Record_Wakeup); function Check_Wakeup (T : Task_ID; Reason : Task_States) return Boolean; pragma Inline (Check_Wakeup); function Check_Unlock (L : Lock_Ptr) return Boolean; pragma Inline (Check_Lock); function Check_Finalize_Lock (L : Lock_Ptr) return Boolean; pragma Inline (Check_Finalize_Lock); ------------------- -- New_Fake_ATCB -- ------------------- function New_Fake_ATCB (Stack_Base : Interfaces.C.unsigned) return Task_ID is Self_ID : Task_ID; P, Q : Fake_ATCB_Ptr; Succeeded : Boolean; Result : Interfaces.C.int; begin -- This section is ticklish. -- We dare not call anything that might require an ATCB, until -- we have the new ATCB in place. -- Note: we don't use Lock_RTS because we don't yet have an ATCB, and -- so can't pass the safety check. Result := mutex_lock (Single_RTS_Lock.L'Access); Q := null; P := Fake_ATCB_List; while P /= null loop if P.Stack_Base = 0 then Q := P; elsif thr_kill (P.Real_ATCB.Common.LL.Thread, 0) /= 0 then -- ???? -- If a C thread that has dependent Ada tasks terminates -- abruptly, e.g. as a result of cancellation, any dependent -- tasks are likely to hang up in termination. P.Stack_Base := 0; Q := P; end if; P := P.Next; end loop; if Q = null then -- Create a new ATCB with zero entries. Self_ID := Next_Fake_ATCB.Real_ATCB'Access; Next_Fake_ATCB.Stack_Base := Stack_Base; Next_Fake_ATCB.Next := Fake_ATCB_List; Fake_ATCB_List := Next_Fake_ATCB; Next_Fake_ATCB := null; else -- Reuse an existing fake ATCB. Self_ID := Q.Real_ATCB'Access; Q.Stack_Base := Stack_Base; end if; -- Do the standard initializations System.Tasking.Initialize_ATCB (Self_ID, null, Null_Address, Null_Task, Fake_Task_Elaborated'Access, System.Priority'First, Task_Info.Unspecified_Task_Info, 0, Self_ID, Succeeded); pragma Assert (Succeeded); -- Record this as the Task_ID for the current thread. Self_ID.Common.LL.Thread := thr_self; Result := thr_setspecific (ATCB_Key, To_Address (Self_ID)); pragma Assert (Result = 0); -- Finally, it is safe to use an allocator in this thread. if Next_Fake_ATCB = null then Next_Fake_ATCB := new Fake_ATCB; end if; Self_ID.Master_of_Task := 0; Self_ID.Master_Within := Self_ID.Master_of_Task + 1; for L in Self_ID.Entry_Calls'Range loop Self_ID.Entry_Calls (L).Self := Self_ID; Self_ID.Entry_Calls (L).Level := L; end loop; Self_ID.Common.State := Runnable; Self_ID.Awake_Count := 1; -- Since this is not an ordinary Ada task, we will start out undeferred Self_ID.Deferral_Level := 0; -- 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); System.Soft_Links.Create_TSD (Self_ID.Common.Compiler_Data); -- ???? -- The following call is commented out to avoid dependence on -- the System.Tasking.Initialization package. -- It seems that if we want Ada.Task_Attributes to work correctly -- for C threads we will need to raise the visibility of this soft -- link to System.Soft_Links. -- We are putting that off until this new functionality is otherwise -- stable. -- System.Tasking.Initialization.Initialize_Attributes_Link.all (T); -- Must not unlock until Next_ATCB is again allocated. for J in Known_Tasks'Range loop if Known_Tasks (J) = null then Known_Tasks (J) := Self_ID; Self_ID.Known_Tasks_Index := J; exit; end if; end loop; Result := mutex_unlock (Single_RTS_Lock.L'Access); -- We cannot use Unlock_RTS because we did not use Write_Lock, and so -- would not pass the checks. return Self_ID; end New_Fake_ATCB; ------------------- -- 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. -- Alternative solutions include: -- 1. Change the PC saved in the system-dependent Context -- parameter to point to code that raises the exception. -- Normal return from this handler will then raise -- the exception after the mask and other system state has -- been restored (see example below). -- 2. Use siglongjmp()/sigsetjmp() to implement exceptions. -- 3. Unmask the signal in the Abortion_Signal exception handler -- (in the RTS). -- The following procedure would be needed if we can't longjmp out of -- a signal handler. (See below.) -- procedure Raise_Abort_Signal is -- begin -- raise Standard'Abort_Signal; -- end if; -- ??? -- The comments above need revising. They are partly obsolete. procedure Abort_Handler (Sig : Signal; Code : access siginfo_t; Context : access ucontext_t) is Self_ID : Task_ID := Self; Result : Interfaces.C.int; Old_Set : aliased sigset_t; begin -- Assuming it is safe to longjmp out of a signal handler, the -- following code can be used: if Self_ID.Deferral_Level = 0 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level and then not Self_ID.Aborting then -- You can comment the following out, -- to make all aborts synchronous, for debugging. Self_ID.Aborting := True; -- Make sure signals used for RTS internal purpose are unmasked Result := thr_sigsetmask (SIG_UNBLOCK, Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access); pragma Assert (Result = 0); raise Standard'Abort_Signal; -- ????? -- Must be certain that the implementation of "raise" -- does not make any OS/thread calls, or at least that -- if it makes any, they are safe for interruption by -- async. signals. end if; -- Otherwise, something like this is required: -- if not Abort_Is_Deferred.all then -- -- Overwrite the return PC address with the address of the -- -- special raise routine, and "return" to that routine's -- -- starting address. -- Context.PC := Raise_Abort_Signal'Address; -- return; -- end if; end Abort_Handler; ------------------- -- Stack_Guard -- ------------------- -- The underlying thread system sets a guard page at the -- bottom of a thread stack, so nothing is needed. procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is begin null; 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 is separate; --------------------- -- 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 rasing Storage_Error in the following routines -- should be able to be handled safely. procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is Result : Interfaces.C.int; begin pragma Assert (Check_Initialize_Lock (Lock_Ptr (L), PO_Level)); if Priority_Ceiling_Emulation then L.Ceiling := Prio; end if; Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then Raise_Exception (Storage_Error'Identity, "Failed to allocate a lock"); end if; end Initialize_Lock; procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is Result : Interfaces.C.int; begin pragma Assert (Check_Initialize_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L)), Level)); Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then Raise_Exception (Storage_Error'Identity, "Failed to allocate a lock"); end if; end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- procedure Finalize_Lock (L : access Lock) is Result : Interfaces.C.int; begin pragma Assert (Check_Finalize_Lock (Lock_Ptr (L))); Result := mutex_destroy (L.L'Access); pragma Assert (Result = 0); end Finalize_Lock; procedure Finalize_Lock (L : access RTS_Lock) is Result : Interfaces.C.int; begin pragma Assert (Check_Finalize_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L)))); Result := mutex_destroy (L.L'Access); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is Result : Interfaces.C.int; begin pragma Assert (Check_Lock (Lock_Ptr (L))); if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then declare Self_Id : constant Task_ID := Self; Saved_Priority : System.Any_Priority; begin if Self_Id.Common.LL.Active_Priority > L.Ceiling then Ceiling_Violation := True; return; end if; Saved_Priority := Self_Id.Common.LL.Active_Priority; if Self_Id.Common.LL.Active_Priority < L.Ceiling then Set_Priority (Self_Id, L.Ceiling); end if; Result := mutex_lock (L.L'Access); pragma Assert (Result = 0); Ceiling_Violation := False; L.Saved_Priority := Saved_Priority; end; else Result := mutex_lock (L.L'Access); pragma Assert (Result = 0); Ceiling_Violation := False; end if; pragma Assert (Record_Lock (Lock_Ptr (L))); end Write_Lock; procedure Write_Lock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then pragma Assert (Check_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L)))); Result := mutex_lock (L.L'Access); pragma Assert (Result = 0); pragma Assert (Record_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L)))); end if; end Write_Lock; procedure Write_Lock (T : Task_ID) is Result : Interfaces.C.int; begin if not Single_Lock then pragma Assert (Check_Lock (To_Lock_Ptr (T.Common.LL.L'Access))); Result := mutex_lock (T.Common.LL.L.L'Access); pragma Assert (Result = 0); pragma Assert (Record_Lock (To_Lock_Ptr (T.Common.LL.L'Access))); end if; end Write_Lock; --------------- -- Read_Lock -- --------------- procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is begin Write_Lock (L, Ceiling_Violation); end Read_Lock; ------------ -- Unlock -- ------------ procedure Unlock (L : access Lock) is Result : Interfaces.C.int; begin pragma Assert (Check_Unlock (Lock_Ptr (L))); if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then declare Self_Id : constant Task_ID := Self; begin Result := mutex_unlock (L.L'Access); pragma Assert (Result = 0); if Self_Id.Common.LL.Active_Priority > L.Saved_Priority then Set_Priority (Self_Id, L.Saved_Priority); end if; end; else Result := mutex_unlock (L.L'Access); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then pragma Assert (Check_Unlock (To_Lock_Ptr (RTS_Lock_Ptr (L)))); Result := mutex_unlock (L.L'Access); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (T : Task_ID) is Result : Interfaces.C.int; begin if not Single_Lock then pragma Assert (Check_Unlock (To_Lock_Ptr (T.Common.LL.L'Access))); Result := mutex_unlock (T.Common.LL.L.L'Access); pragma Assert (Result = 0); end if; end Unlock; -- For the time delay implementation, we need to make sure we -- achieve following criteria: -- 1) We have to delay at least for the amount requested. -- 2) We have to give up CPU even though the actual delay does not -- result in blocking. -- 3) Except for restricted run-time systems that do not support -- ATC or task abort, the delay must be interrupted by the -- abort_task operation. -- 4) The implementation has to be efficient so that the delay overhead -- is relatively cheap. -- (1)-(3) are Ada requirements. Even though (2) is an Annex-D -- requirement we still want to provide the effect in all cases. -- The reason is that users may want to use short delays to implement -- their own scheduling effect in the absence of language provided -- scheduling policies. --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration is TS : aliased timespec; Result : Interfaces.C.int; begin Result := clock_gettime (CLOCK_REALTIME, 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; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is begin if Do_Yield then System.OS_Interface.thr_yield; end if; end Yield; ------------------ -- Set_Priority -- ------------------ procedure Set_Priority (T : Task_ID; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is Result : Interfaces.C.int; Param : aliased struct_pcparms; use Task_Info; begin T.Common.Current_Priority := Prio; if Priority_Ceiling_Emulation then T.Common.LL.Active_Priority := Prio; end if; if Using_Real_Time_Class then Param.pc_cid := Prio_Param.pc_cid; Param.rt_pri := pri_t (Prio); Param.rt_tqsecs := Prio_Param.rt_tqsecs; Param.rt_tqnsecs := Prio_Param.rt_tqnsecs; Result := Interfaces.C.int ( priocntl (PC_VERSION, P_LWPID, T.Common.LL.LWP, PC_SETPARMS, Param'Address)); else if T.Common.Task_Info /= null and then not T.Common.Task_Info.Bound_To_LWP then -- The task is not bound to a LWP, so use thr_setprio Result := thr_setprio (T.Common.LL.Thread, Interfaces.C.int (Prio)); else -- The task is bound to a LWP, use priocntl -- ??? TBD null; end if; end if; 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 Result : Interfaces.C.int; Proc : processorid_t; -- User processor # Last_Proc : processorid_t; -- Last processor # use System.Task_Info; begin Self_ID.Common.LL.Thread := thr_self; Self_ID.Common.LL.LWP := lwp_self; if Self_ID.Common.Task_Info /= null then if Self_ID.Common.Task_Info.New_LWP and then Self_ID.Common.Task_Info.CPU /= CPU_UNCHANGED then Last_Proc := Num_Procs - 1; if Self_ID.Common.Task_Info.CPU = ANY_CPU then Result := 0; Proc := 0; while Proc < Last_Proc loop Result := p_online (Proc, PR_STATUS); exit when Result = PR_ONLINE; Proc := Proc + 1; end loop; Result := processor_bind (P_LWPID, P_MYID, Proc, null); pragma Assert (Result = 0); else -- Use specified processor if Self_ID.Common.Task_Info.CPU < 0 or else Self_ID.Common.Task_Info.CPU > Last_Proc then raise Invalid_CPU_Number; end if; Result := processor_bind (P_LWPID, P_MYID, Self_ID.Common.Task_Info.CPU, null); pragma Assert (Result = 0); end if; end if; end if; Result := thr_setspecific (ATCB_Key, To_Address (Self_ID)); pragma Assert (Result = 0); -- We need the above code even if we do direct fetch of Task_ID in Self -- for the main task on Sun, x86 Solaris and for gcc 2.7.2. Lock_RTS; for J in Known_Tasks'Range loop if Known_Tasks (J) = null then Known_Tasks (J) := Self_ID; Self_ID.Known_Tasks_Index := J; exit; end if; end loop; Unlock_RTS; 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; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is Result : Interfaces.C.int := 0; 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); Self_ID.Common.LL.Thread := To_thread_t (-1); if not Single_Lock then Result := mutex_init (Self_ID.Common.LL.L.L'Access, USYNC_THREAD, System.Null_Address); Self_ID.Common.LL.L.Level := Private_Task_Serial_Number (Self_ID.Serial_Number); pragma Assert (Result = 0 or else Result = ENOMEM); end if; if Result = 0 then Result := cond_init (Self_ID.Common.LL.CV'Access, USYNC_THREAD, 0); pragma Assert (Result = 0 or else Result = ENOMEM); end if; if Result = 0 then Succeeded := True; else if not Single_Lock then Result := mutex_destroy (Self_ID.Common.LL.L.L'Access); pragma Assert (Result = 0); end if; Succeeded := False; end if; 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 Result : Interfaces.C.int; Adjusted_Stack_Size : Interfaces.C.size_t; Opts : Interfaces.C.int := THR_DETACHED; Page_Size : constant System.Parameters.Size_Type := 4096; -- This constant is for reserving extra space at the -- end of the stack, which can be used by the stack -- checking as guard page. The idea is that we need -- to have at least Stack_Size bytes available for -- actual use. use System.Task_Info; begin if Stack_Size = System.Parameters.Unspecified_Size then Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size + Page_Size); elsif Stack_Size < Minimum_Stack_Size then Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size + Page_Size); else Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size + Page_Size); end if; -- 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. if T.Common.Task_Info /= null then if T.Common.Task_Info.New_LWP then Opts := Opts + THR_NEW_LWP; end if; if T.Common.Task_Info.Bound_To_LWP then Opts := Opts + THR_BOUND; end if; else Opts := THR_DETACHED + THR_BOUND; end if; Result := thr_create (System.Null_Address, Adjusted_Stack_Size, Thread_Body_Access (Wrapper), To_Address (T), Opts, T.Common.LL.Thread'Access); Succeeded := Result = 0; pragma Assert (Result = 0 or else Result = ENOMEM or else Result = EAGAIN); end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_ID) is Result : Interfaces.C.int; Tmp : Task_ID := T; procedure Free is new Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID); begin T.Common.LL.Thread := To_thread_t (0); if not Single_Lock then Result := mutex_destroy (T.Common.LL.L.L'Access); pragma Assert (Result = 0); end if; Result := 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); end Finalize_TCB; --------------- -- Exit_Task -- --------------- -- This procedure must be called with abort deferred. -- It can no longer call Self or access -- the current task's ATCB, since the ATCB has been deallocated. procedure Exit_Task is begin thr_exit (System.Null_Address); end Exit_Task; ---------------- -- Abort_Task -- ---------------- procedure Abort_Task (T : Task_ID) is Result : Interfaces.C.int; begin pragma Assert (T /= Self); Result := thr_kill (T.Common.LL.Thread, Signal (System.Interrupt_Management.Abort_Task_Interrupt)); null; pragma Assert (Result = 0); end Abort_Task; ----------- -- Sleep -- ----------- procedure Sleep (Self_ID : Task_ID; Reason : Task_States) is Result : Interfaces.C.int; begin pragma Assert (Check_Sleep (Reason)); if Dynamic_Priority_Support and then Self_ID.Pending_Priority_Change then Self_ID.Pending_Priority_Change := False; Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority; Set_Priority (Self_ID, Self_ID.Common.Base_Priority); end if; if Single_Lock then Result := cond_wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access); else Result := cond_wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access); end if; pragma Assert (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason)); pragma Assert (Result = 0 or else Result = EINTR); end Sleep; -- Note that we are relying heaviliy here on the GNAT feature -- that Calendar.Time, System.Real_Time.Time, Duration, and -- System.Real_Time.Time_Span are all represented in the same -- way, i.e., as a 64-bit count of nanoseconds. -- This allows us to always pass the timeout value as a Duration. -- ??? -- We are taking liberties here with the semantics of the delays. -- That is, we make no distinction between delays on the Calendar clock -- and delays on the Real_Time clock. That is technically incorrect, if -- the Calendar clock happens to be reset or adjusted. -- To solve this defect will require modification to the compiler -- interface, so that it can pass through more information, to tell -- us here which clock to use! -- cond_timedwait will return if any of the following happens: -- 1) some other task did cond_signal on this condition variable -- In this case, the return value is 0 -- 2) the call just returned, for no good reason -- This is called a "spurious wakeup". -- In this case, the return value may also be 0. -- 3) the time delay expires -- In this case, the return value is ETIME -- 4) this task received a signal, which was handled by some -- handler procedure, and now the thread is resuming execution -- UNIX calls this an "interrupted" system call. -- In this case, the return value is EINTR -- If the cond_timedwait returns 0 or EINTR, it is still -- possible that the time has actually expired, and by chance -- a signal or cond_signal occurred at around the same time. -- We have also observed that on some OS's the value ETIME -- will be returned, but the clock will show that the full delay -- has not yet expired. -- For these reasons, we need to check the clock after return -- from cond_timedwait. If the time has expired, we will set -- Timedout = True. -- This check might be omitted for systems on which the -- cond_timedwait() never returns early or wakes up spuriously. -- Annex D requires that completion of a delay cause the task -- to go to the end of its priority queue, regardless of whether -- the task actually was suspended by the delay. Since -- cond_timedwait does not do this on Solaris, we add a call -- to thr_yield at the end. We might do this at the beginning, -- instead, but then the round-robin effect would not be the -- same; the delayed task would be ahead of other tasks of the -- same priority that awoke while it was sleeping. -- For Timed_Sleep, we are expecting possible cond_signals -- to indicate other events (e.g., completion of a RV or -- completion of the abortable part of an async. select), -- we want to always return if interrupted. The caller will -- be responsible for checking the task state to see whether -- the wakeup was spurious, and to go back to sleep again -- in that case. We don't need to check for pending abort -- or priority change on the way in our out; that is the -- caller's responsibility. -- For Timed_Delay, we are not expecting any cond_signals or -- other interruptions, except for priority changes and aborts. -- Therefore, we don't want to return unless the delay has -- actually expired, or the call has been aborted. In this -- case, since we want to implement the entire delay statement -- semantics, we do need to check for pending abort and priority -- changes. We can quietly handle priority changes inside the -- procedure, since there is no entry-queue reordering involved. ----------------- -- Timed_Sleep -- ----------------- procedure Timed_Sleep (Self_ID : Task_ID; Time : Duration; Mode : ST.Delay_Modes; Reason : System.Tasking.Task_States; Timedout : out Boolean; Yielded : out Boolean) is Check_Time : constant Duration := Monotonic_Clock; Abs_Time : Duration; Request : aliased timespec; Result : Interfaces.C.int; begin pragma Assert (Check_Sleep (Reason)); Timedout := True; Yielded := False; if Mode = Relative then Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time; else Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time); end if; if Abs_Time > Check_Time then Request := To_Timespec (Abs_Time); loop exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level or else (Dynamic_Priority_Support and then Self_ID.Pending_Priority_Change); if Single_Lock then Result := cond_timedwait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access, Request'Access); else Result := cond_timedwait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access, Request'Access); end if; Yielded := True; exit when Abs_Time <= Monotonic_Clock; if Result = 0 or Result = EINTR then -- somebody may have called Wakeup for us Timedout := False; exit; end if; pragma Assert (Result = ETIME); end loop; end if; pragma Assert (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason)); end Timed_Sleep; ----------------- -- Timed_Delay -- ----------------- procedure Timed_Delay (Self_ID : Task_ID; Time : Duration; Mode : ST.Delay_Modes) is Check_Time : constant Duration := Monotonic_Clock; Abs_Time : Duration; Request : aliased timespec; Result : Interfaces.C.int; Yielded : Boolean := False; begin -- Only the little window between deferring abort and -- locking Self_ID is the reason we need to -- check for pending abort and priority change below! SSL.Abort_Defer.all; if Single_Lock then Lock_RTS; end if; Write_Lock (Self_ID); if Mode = Relative then Abs_Time := Time + Check_Time; else Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time); end if; if Abs_Time > Check_Time then Request := To_Timespec (Abs_Time); Self_ID.Common.State := Delay_Sleep; pragma Assert (Check_Sleep (Delay_Sleep)); loop if Dynamic_Priority_Support and then Self_ID.Pending_Priority_Change then Self_ID.Pending_Priority_Change := False; Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority; Set_Priority (Self_ID, Self_ID.Common.Base_Priority); end if; exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; if Single_Lock then Result := cond_timedwait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access, Request'Access); else Result := cond_timedwait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access, Request'Access); end if; Yielded := True; exit when Abs_Time <= Monotonic_Clock; pragma Assert (Result = 0 or else Result = ETIME or else Result = EINTR); end loop; pragma Assert (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Delay_Sleep)); Self_ID.Common.State := Runnable; end if; Unlock (Self_ID); if Single_Lock then Unlock_RTS; end if; if not Yielded then thr_yield; end if; SSL.Abort_Undefer.all; end Timed_Delay; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_ID; Reason : Task_States) is Result : Interfaces.C.int; begin pragma Assert (Check_Wakeup (T, Reason)); Result := cond_signal (T.Common.LL.CV'Access); pragma Assert (Result = 0); end Wakeup; --------------------------- -- Check_Initialize_Lock -- --------------------------- -- The following code is intended to check some of the invariant -- assertions related to lock usage, on which we depend. function Check_Initialize_Lock (L : Lock_Ptr; Level : Lock_Level) return Boolean is Self_ID : constant Task_ID := Self; begin -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; -- Check that the lock is not yet initialized if L.Level /= 0 then return False; end if; L.Level := Lock_Level'Pos (Level) + 1; return True; end Check_Initialize_Lock; ---------------- -- Check_Lock -- ---------------- function Check_Lock (L : Lock_Ptr) return Boolean is Self_ID : Task_ID := Self; P : Lock_Ptr; begin -- Check that the argument is not null if L = null then return False; end if; -- Check that L is not frozen if L.Frozen then return False; end if; -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; -- Check that caller is not holding this lock already if L.Owner = To_Owner_ID (Self_ID) then return False; end if; if Single_Lock then return True; end if; -- Check that TCB lock order rules are satisfied P := Self_ID.Common.LL.Locks; if P /= null then if P.Level >= L.Level and then (P.Level > 2 or else L.Level > 2) then return False; end if; end if; return True; end Check_Lock; ----------------- -- Record_Lock -- ----------------- function Record_Lock (L : Lock_Ptr) return Boolean is Self_ID : Task_ID := Self; P : Lock_Ptr; begin Lock_Count := Lock_Count + 1; -- There should be no owner for this lock at this point if L.Owner /= null then return False; end if; -- Record new owner L.Owner := To_Owner_ID (Self_ID); if Single_Lock then return True; end if; -- Check that TCB lock order rules are satisfied P := Self_ID.Common.LL.Locks; if P /= null then L.Next := P; end if; Self_ID.Common.LL.Locking := null; Self_ID.Common.LL.Locks := L; return True; end Record_Lock; ----------------- -- Check_Sleep -- ----------------- function Check_Sleep (Reason : Task_States) return Boolean is Self_ID : Task_ID := Self; P : Lock_Ptr; begin -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; if Single_Lock then return True; end if; -- Check that caller is holding own lock, on top of list if Self_ID.Common.LL.Locks /= To_Lock_Ptr (Self_ID.Common.LL.L'Access) then return False; end if; -- Check that TCB lock order rules are satisfied if Self_ID.Common.LL.Locks.Next /= null then return False; end if; Self_ID.Common.LL.L.Owner := null; P := Self_ID.Common.LL.Locks; Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next; P.Next := null; return True; end Check_Sleep; ------------------- -- Record_Wakeup -- ------------------- function Record_Wakeup (L : Lock_Ptr; Reason : Task_States) return Boolean is Self_ID : Task_ID := Self; P : Lock_Ptr; begin -- Record new owner L.Owner := To_Owner_ID (Self_ID); if Single_Lock then return True; end if; -- Check that TCB lock order rules are satisfied P := Self_ID.Common.LL.Locks; if P /= null then L.Next := P; end if; Self_ID.Common.LL.Locking := null; Self_ID.Common.LL.Locks := L; return True; end Record_Wakeup; ------------------ -- Check_Wakeup -- ------------------ function Check_Wakeup (T : Task_ID; Reason : Task_States) return Boolean is Self_ID : Task_ID := Self; begin -- Is caller holding T's lock? if T.Common.LL.L.Owner /= To_Owner_ID (Self_ID) then return False; end if; -- Are reasons for wakeup and sleep consistent? if T.Common.State /= Reason then return False; end if; return True; end Check_Wakeup; ------------------ -- Check_Unlock -- ------------------ function Check_Unlock (L : Lock_Ptr) return Boolean is Self_ID : Task_ID := Self; P : Lock_Ptr; begin Unlock_Count := Unlock_Count + 1; if L = null then return False; end if; if L.Buddy /= null then return False; end if; if L.Level = 4 then Check_Count := Unlock_Count; end if; if Unlock_Count - Check_Count > 1000 then Check_Count := Unlock_Count; Old_Owner := To_Task_ID (Single_RTS_Lock.Owner); end if; -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; -- Check that caller is holding this lock, on top of list if Self_ID.Common.LL.Locks /= L then return False; end if; -- Record there is no owner now L.Owner := null; P := Self_ID.Common.LL.Locks; Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next; P.Next := null; return True; end Check_Unlock; -------------------- -- Check_Finalize -- -------------------- function Check_Finalize_Lock (L : Lock_Ptr) return Boolean is Self_ID : Task_ID := Self; begin -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; -- Check that no one is holding this lock if L.Owner /= null then return False; end if; L.Frozen := True; return True; end Check_Finalize_Lock; ---------------- -- Check_Exit -- ---------------- function Check_Exit (Self_ID : Task_ID) return Boolean is begin -- Check that caller is just holding Global_Task_Lock -- and no other locks if Self_ID.Common.LL.Locks = null then return False; end if; -- 2 = Global_Task_Level if Self_ID.Common.LL.Locks.Level /= 2 then return False; end if; if Self_ID.Common.LL.Locks.Next /= null then return False; end if; -- Check that caller is abort-deferred if Self_ID.Deferral_Level <= 0 then return False; end if; return True; end Check_Exit; -------------------- -- Check_No_Locks -- -------------------- function Check_No_Locks (Self_ID : Task_ID) return Boolean is begin return Self_ID.Common.LL.Locks = null; 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 begin if T.Common.LL.Thread /= Thread_Self then return thr_suspend (T.Common.LL.Thread) = 0; else return True; end if; end Suspend_Task; ----------------- -- Resume_Task -- ----------------- function Resume_Task (T : ST.Task_ID; Thread_Self : Thread_Id) return Boolean is begin if T.Common.LL.Thread /= Thread_Self then return thr_continue (T.Common.LL.Thread) = 0; else return True; end if; end Resume_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : ST.Task_ID) is act : aliased struct_sigaction; old_act : aliased struct_sigaction; Tmp_Set : aliased sigset_t; Result : Interfaces.C.int; procedure Configure_Processors; -- Processors configuration -- The user can specify a processor which the program should run -- on to emulate a single-processor system. This can be easily -- done by setting environment variable GNAT_PROCESSOR to one of -- the following : -- -- -2 : use the default configuration (run the program on all -- available processors) - this is the same as having -- GNAT_PROCESSOR unset -- -1 : let the RTS choose one processor and run the program on -- that processor -- 0 .. Last_Proc : run the program on the specified processor -- -- Last_Proc is equal to the value of the system variable -- _SC_NPROCESSORS_CONF, minus one. procedure Configure_Processors is Proc_Acc : constant GNAT.OS_Lib.String_Access := GNAT.OS_Lib.Getenv ("GNAT_PROCESSOR"); Proc : aliased processorid_t; -- User processor # Last_Proc : processorid_t; -- Last processor # begin if Proc_Acc.all'Length /= 0 then -- Environment variable is defined Last_Proc := Num_Procs - 1; if Last_Proc /= -1 then Proc := processorid_t'Value (Proc_Acc.all); if Proc <= -2 or else Proc > Last_Proc then -- Use the default configuration null; elsif Proc = -1 then -- Choose a processor Result := 0; while Proc < Last_Proc loop Proc := Proc + 1; Result := p_online (Proc, PR_STATUS); exit when Result = PR_ONLINE; end loop; pragma Assert (Result = PR_ONLINE); Result := processor_bind (P_PID, P_MYID, Proc, null); pragma Assert (Result = 0); else -- Use user processor Result := processor_bind (P_PID, P_MYID, Proc, null); pragma Assert (Result = 0); end if; end if; end if; exception when Constraint_Error => -- Illegal environment variable GNAT_PROCESSOR - ignored null; end Configure_Processors; -- Start of processing for Initialize begin Environment_Task_ID := Environment_Task; -- This is done in Enter_Task, but this is too late for the -- Environment Task, since we need to call Self in Check_Locks when -- the run time is compiled with assertions on. Result := thr_setspecific (ATCB_Key, To_Address (Environment_Task)); pragma Assert (Result = 0); -- Initialize the lock used to synchronize chain of all ATCBs. Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); Enter_Task (Environment_Task); -- Install the abort-signal handler -- Set sa_flags to SA_NODEFER so that during the handler execution -- we do not change the Signal_Mask to be masked for the Abort_Signal. -- This is a temporary fix to the problem that the Signal_Mask is -- not restored after the exception (longjmp) from the handler. -- The right fix should be made in sigsetjmp so that we save -- the Signal_Set and restore it after a longjmp. -- In that case, this field should be changed back to 0. ??? act.sa_flags := 16; 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); Configure_Processors; -- Create a free ATCB for use on the Fake_ATCB_List. Next_Fake_ATCB := new Fake_ATCB; end Initialize; -- Package elaboration begin declare Result : Interfaces.C.int; begin -- Mask Environment task for all signals. The original mask of the -- Environment task will be recovered by Interrupt_Server task -- during the elaboration of s-interr.adb. System.Interrupt_Management.Operations.Set_Interrupt_Mask (System.Interrupt_Management.Operations.All_Tasks_Mask'Access); -- 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; -- We need the following code to support automatic creation of fake -- ATCB's for C threads that call the Ada run-time system, even if -- we use a faster way of getting Self for real Ada tasks. Result := thr_keycreate (ATCB_Key'Access, System.Null_Address); pragma Assert (Result = 0); end; if Dispatching_Policy = 'F' then declare Result : Interfaces.C.long; Class_Info : aliased struct_pcinfo; Secs, Nsecs : Interfaces.C.long; begin -- If a pragma Time_Slice is specified, takes the value in account. if Time_Slice_Val > 0 then -- Convert Time_Slice_Val (microseconds) into seconds and -- nanoseconds Secs := Time_Slice_Val / 1_000_000; Nsecs := (Time_Slice_Val rem 1_000_000) * 1_000; -- Otherwise, default to no time slicing (i.e run until blocked) else Secs := RT_TQINF; Nsecs := RT_TQINF; end if; -- Get the real time class id. Class_Info.pc_clname (1) := 'R'; Class_Info.pc_clname (2) := 'T'; Class_Info.pc_clname (3) := ASCII.NUL; Result := priocntl (PC_VERSION, P_LWPID, P_MYID, PC_GETCID, Class_Info'Address); -- Request the real time class Prio_Param.pc_cid := Class_Info.pc_cid; Prio_Param.rt_pri := pri_t (Class_Info.rt_maxpri); Prio_Param.rt_tqsecs := Secs; Prio_Param.rt_tqnsecs := Nsecs; Result := priocntl (PC_VERSION, P_LWPID, P_MYID, PC_SETPARMS, Prio_Param'Address); Using_Real_Time_Class := Result /= -1; end; end if; end System.Task_Primitives.Operations;