| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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 -- |
| -- -- |
| -- $Revision: 1.1 $ |
| -- -- |
| -- Copyright (C) 1991-2001, Florida State University -- |
| -- -- |
| -- 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. It is -- |
| -- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- |
| -- State University (http://www.gnat.com). -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- 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 -- |
| ------------------ |
| |
| ATCB_Magic_Code : constant := 16#ADAADAAD#; |
| -- This is used to allow us to catch attempts to call Self |
| -- from outside an Ada task, with high probability. |
| -- For an Ada task, Task_Wrapper.Magic_Number = ATCB_Magic_Code. |
| |
| -- 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. |
| |
| All_Tasks_L : aliased System.Task_Primitives.RTS_Lock; |
| -- See comments on locking rules in System.Tasking (spec). |
| |
| 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 -- |
| ------------------------ |
| |
| Dynamic_Priority_Support : constant Boolean := True; |
| -- controls whether we poll for pending priority changes during sleeps |
| |
| 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 All_Tasks_L; |
| -- 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); |
| |
| type Ptr is access Task_ID; |
| function To_Ptr is new Unchecked_Conversion (Interfaces.C.unsigned, Ptr); |
| function To_Ptr is new Unchecked_Conversion (System.Address, Ptr); |
| |
| type Iptr is access Interfaces.C.unsigned; |
| function To_Iptr is new Unchecked_Conversion (Interfaces.C.unsigned, Iptr); |
| |
| 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. |
| |
| ------------ |
| -- 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 "Write_Lock (All_Tasks_L'Access);" because |
| -- we don't yet have an ATCB, and so can't pass the safety check. |
| |
| Result := mutex_lock (All_Tasks_L.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 (All_Tasks_L.L'Access); |
| |
| -- We cannot use "Unlock (All_Tasks_L'Access);" 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 All_Tasks_L, 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) is |
| Result : Interfaces.C.int; |
| |
| begin |
| 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 Write_Lock; |
| |
| procedure Write_Lock (T : Task_ID) is |
| Result : Interfaces.C.int; |
| |
| begin |
| 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 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) is |
| Result : Interfaces.C.int; |
| |
| begin |
| pragma Assert (Check_Unlock (To_Lock_Ptr (RTS_Lock_Ptr (L)))); |
| Result := mutex_unlock (L.L'Access); |
| pragma Assert (Result = 0); |
| end Unlock; |
| |
| procedure Unlock (T : Task_ID) is |
| Result : Interfaces.C.int; |
| |
| begin |
| 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 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_All_Tasks_List; |
| |
| for I in Known_Tasks'Range loop |
| if Known_Tasks (I) = null then |
| Known_Tasks (I) := Self_ID; |
| Self_ID.Known_Tasks_Index := I; |
| exit; |
| end if; |
| end loop; |
| Unlock_All_Tasks_List; |
| 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; |
| |
| 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); |
| 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); |
| |
| if Result = 0 then |
| Result := cond_init (Self_ID.Common.LL.CV'Access, USYNC_THREAD, 0); |
| pragma Assert (Result = 0 or else Result = ENOMEM); |
| |
| if Result /= 0 then |
| Result := mutex_destroy (Self_ID.Common.LL.L.L'Access); |
| pragma Assert (Result = 0); |
| Succeeded := False; |
| else |
| Succeeded := True; |
| end if; |
| |
| else |
| 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); |
| Result := mutex_destroy (T.Common.LL.L.L'Access); |
| pragma Assert (Result = 0); |
| 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; |
| |
| Result := cond_wait |
| (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access); |
| pragma Assert (Result = 0 or else Result = EINTR); |
| pragma Assert (Record_Wakeup |
| (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason)); |
| 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 -- |
| ----------------- |
| |
| -- 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. |
| |
| -- Yielded should be False unles we know for certain that the |
| -- operation resulted in the calling task going to the end of |
| -- the dispatching queue for its priority. |
| |
| -- ??? |
| -- This version presumes the worst, so Yielded is always False. |
| -- On some targets, if cond_timedwait always yields, we could |
| -- set Yielded to True just before the cond_timedwait call. |
| |
| 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); |
| |
| Result := cond_timedwait (Self_ID.Common.LL.CV'Access, |
| Self_ID.Common.LL.L.L'Access, Request'Access); |
| |
| 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 -- |
| ----------------- |
| |
| -- 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 |
| Check_Time : constant Duration := Monotonic_Clock; |
| Abs_Time : Duration; |
| Request : aliased timespec; |
| Result : Interfaces.C.int; |
| |
| 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; |
| 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; |
| |
| Result := cond_timedwait (Self_ID.Common.LL.CV'Access, |
| Self_ID.Common.LL.L.L'Access, Request'Access); |
| |
| 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); |
| thr_yield; |
| 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; |
| |
| -- 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); |
| |
| -- 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; |
| |
| -- 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); |
| |
| -- 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 (All_Tasks_L.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_All_Tasks_List -- |
| ------------------------- |
| |
| procedure Lock_All_Tasks_List is |
| begin |
| Write_Lock (All_Tasks_L'Access); |
| end Lock_All_Tasks_List; |
| |
| --------------------------- |
| -- Unlock_All_Tasks_List -- |
| --------------------------- |
| |
| procedure Unlock_All_Tasks_List is |
| begin |
| Unlock (All_Tasks_L'Access); |
| end Unlock_All_Tasks_List; |
| |
| ------------------ |
| -- 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"); |
| begin |
| if Proc_Acc.all'Length /= 0 then |
| |
| -- Environment variable is defined |
| |
| declare |
| Proc : aliased processorid_t; -- User processor # |
| Last_Proc : processorid_t; -- Last processor # |
| |
| begin |
| Last_Proc := Num_Procs - 1; |
| |
| if Last_Proc = -1 then |
| |
| -- Unable to read system variable _SC_NPROCESSORS_CONF |
| -- Ignore environment variable GNAT_PROCESSOR |
| |
| null; |
| |
| else |
| Proc := processorid_t'Value (Proc_Acc.all); |
| |
| if Proc < -2 or Proc > Last_Proc then |
| raise Constraint_Error; |
| |
| elsif Proc = -2 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; |
| |
| exception |
| when Constraint_Error => |
| |
| -- Illegal environment variable GNAT_PROCESSOR - ignored |
| |
| null; |
| end; |
| end if; |
| 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 (All_Tasks_L'Access, All_Tasks_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; |
