------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2020, Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a POSIX-like version of this package -- This package contains all the GNULL primitives that interface directly with -- the underlying OS. -- Note: this file can only be used for POSIX compliant systems that implement -- SCHED_FIFO and Ceiling Locking correctly. -- For configurations where SCHED_FIFO and priority ceiling are not a -- requirement, this file can also be used (e.g AiX threads) with Ada.Unchecked_Conversion; with Interfaces.C; with System.Tasking.Debug; with System.Interrupt_Management; with System.OS_Constants; with System.OS_Primitives; with System.Task_Info; with System.Soft_Links; -- We use System.Soft_Links instead of System.Tasking.Initialization -- because the later is a higher level package that we shouldn't depend on. -- For example when using the restricted run time, it is replaced by -- System.Tasking.Restricted.Stages. package body System.Task_Primitives.Operations is package OSC renames System.OS_Constants; package SSL renames System.Soft_Links; use System.Tasking.Debug; use System.Tasking; use Interfaces.C; use System.OS_Interface; use System.Parameters; use System.OS_Primitives; ---------------- -- Local Data -- ---------------- -- The followings are logically constants, but need to be initialized -- at run time. Single_RTS_Lock : aliased RTS_Lock; -- This is a lock to allow only one thread of control in the RTS at -- a time; it is used to execute in mutual exclusion from all other tasks. -- Used to protect All_Tasks_List Environment_Task_Id : Task_Id; -- A variable to hold Task_Id for the environment task Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); -- Value of the pragma Locking_Policy: -- 'C' for Ceiling_Locking -- 'I' for Inherit_Locking -- ' ' for none. Unblocked_Signal_Mask : aliased sigset_t; -- The set of signals that should unblocked in all tasks -- The followings are internal configuration constants needed Next_Serial_Number : Task_Serial_Number := 100; -- We start at 100, to reserve some special values for -- using in error checking. Time_Slice_Val : Integer; pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); Dispatching_Policy : Character; pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy"); Foreign_Task_Elaborated : aliased Boolean := True; -- Used to identified fake tasks (i.e., non-Ada Threads) Use_Alternate_Stack : constant Boolean := Alternate_Stack_Size /= 0; -- Whether to use an alternate signal stack for stack overflows Abort_Handler_Installed : Boolean := False; -- True if a handler for the abort signal is installed type RTS_Lock_Ptr is not null access all RTS_Lock; function Init_Mutex (L : RTS_Lock_Ptr; Prio : Any_Priority) return int; -- Initialize the mutex L. If Ceiling_Support is True, then set the ceiling -- to Prio. Returns 0 for success, or ENOMEM for out-of-memory. function Get_Policy (Prio : System.Any_Priority) return Character; pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching"); -- Get priority specific dispatching policy -------------------- -- Local Packages -- -------------------- package Specific is procedure Initialize (Environment_Task : Task_Id); pragma Inline (Initialize); -- Initialize various data needed by this package function Is_Valid_Task return Boolean; pragma Inline (Is_Valid_Task); -- Does executing thread have a TCB? procedure Set (Self_Id : Task_Id); pragma Inline (Set); -- Set the self id for the current task function Self return Task_Id; pragma Inline (Self); -- Return a pointer to the Ada Task Control Block of the calling task end Specific; package body Specific is separate; -- The body of this package is target specific package Monotonic is function Monotonic_Clock return Duration; pragma Inline (Monotonic_Clock); -- Returns an absolute time, represented as an offset relative to some -- unspecified starting point, typically system boot time. This clock -- is not affected by discontinuous jumps in the system time. function RT_Resolution return Duration; pragma Inline (RT_Resolution); -- Returns resolution of the underlying clock used to implement RT_Clock procedure Timed_Sleep (Self_ID : ST.Task_Id; Time : Duration; Mode : ST.Delay_Modes; Reason : System.Tasking.Task_States; Timedout : out Boolean; Yielded : out Boolean); -- Combination of Sleep (above) and Timed_Delay procedure Timed_Delay (Self_ID : ST.Task_Id; Time : Duration; Mode : ST.Delay_Modes); -- Implement the semantics of the delay statement. -- The caller should be abort-deferred and should not hold any locks. end Monotonic; package body Monotonic is separate; ---------------------------------- -- ATCB allocation/deallocation -- ---------------------------------- package body ATCB_Allocation is separate; -- The body of this package is shared across several targets --------------------------------- -- Support for foreign threads -- --------------------------------- function Register_Foreign_Thread (Thread : Thread_Id; Sec_Stack_Size : Size_Type := Unspecified_Size) return Task_Id; -- Allocate and initialize a new ATCB for the current Thread. The size of -- the secondary stack can be optionally specified. function Register_Foreign_Thread (Thread : Thread_Id; Sec_Stack_Size : Size_Type := Unspecified_Size) return Task_Id is separate; ----------------------- -- Local Subprograms -- ----------------------- procedure Abort_Handler (Sig : Signal); -- Signal handler used to implement asynchronous abort. -- See also comment before body, below. function To_Address is new Ada.Unchecked_Conversion (Task_Id, System.Address); function GNAT_pthread_condattr_setup (attr : access pthread_condattr_t) return int; pragma Import (C, GNAT_pthread_condattr_setup, "__gnat_pthread_condattr_setup"); ------------------- -- Abort_Handler -- ------------------- -- Target-dependent binding of inter-thread Abort signal to the raising of -- the Abort_Signal exception. -- The technical issues and alternatives here are essentially the -- same as for raising exceptions in response to other signals -- (e.g. Storage_Error). See code and comments in the package body -- System.Interrupt_Management. -- Some implementations may not allow an exception to be propagated out of -- a handler, and others might leave the signal or interrupt that invoked -- this handler masked after the exceptional return to the application -- code. -- GNAT exceptions are originally implemented using setjmp()/longjmp(). On -- most UNIX systems, this will allow transfer out of a signal handler, -- which is usually the only mechanism available for implementing -- asynchronous handlers of this kind. However, some systems do not -- restore the signal mask on longjmp(), leaving the abort signal masked. procedure Abort_Handler (Sig : Signal) is pragma Unreferenced (Sig); T : constant Task_Id := Self; Old_Set : aliased sigset_t; Result : Interfaces.C.int; pragma Warnings (Off, Result); begin -- It's not safe to raise an exception when using GCC ZCX mechanism. -- Note that we still need to install a signal handler, since in some -- cases (e.g. shutdown of the Server_Task in System.Interrupts) we -- need to send the Abort signal to a task. if ZCX_By_Default then return; end if; if T.Deferral_Level = 0 and then T.Pending_ATC_Level < T.ATC_Nesting_Level and then not T.Aborting then T.Aborting := True; -- Make sure signals used for RTS internal purpose are unmasked Result := pthread_sigmask (SIG_UNBLOCK, Unblocked_Signal_Mask'Access, Old_Set'Access); pragma Assert (Result = 0); raise Standard'Abort_Signal; end if; end Abort_Handler; ----------------- -- Stack_Guard -- ----------------- procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is Stack_Base : constant Address := Get_Stack_Base (T.Common.LL.Thread); Page_Size : Address; Res : Interfaces.C.int; begin if Stack_Base_Available then -- Compute the guard page address Page_Size := Address (Get_Page_Size); Res := mprotect (Stack_Base - (Stack_Base mod Page_Size) + Page_Size, size_t (Page_Size), prot => (if On then PROT_ON else PROT_OFF)); pragma Assert (Res = 0); end if; end Stack_Guard; -------------------- -- Get_Thread_Id -- -------------------- function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is begin return T.Common.LL.Thread; end Get_Thread_Id; ---------- -- Self -- ---------- function Self return Task_Id renames Specific.Self; ---------------- -- Init_Mutex -- ---------------- function Init_Mutex (L : RTS_Lock_Ptr; Prio : Any_Priority) return int is Attributes : aliased pthread_mutexattr_t; Result : int; Result_2 : aliased int; begin Result := pthread_mutexattr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then return Result; end if; if Locking_Policy = 'C' then Result := pthread_mutexattr_setprotocol (Attributes'Access, PTHREAD_PRIO_PROTECT); pragma Assert (Result = 0); Result := pthread_mutexattr_getprotocol (Attributes'Access, Result_2'Access); if Result_2 /= PTHREAD_PRIO_PROTECT then raise Program_Error with "setprotocol failed"; end if; Result := pthread_mutexattr_setprioceiling (Attributes'Access, To_Target_Priority (Prio)); pragma Assert (Result = 0); elsif Locking_Policy = 'I' then Result := pthread_mutexattr_setprotocol (Attributes'Access, PTHREAD_PRIO_INHERIT); pragma Assert (Result = 0); end if; Result := pthread_mutex_init (L, Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); Result_2 := pthread_mutexattr_destroy (Attributes'Access); pragma Assert (Result_2 = 0); return Result; end Init_Mutex; --------------------- -- Initialize_Lock -- --------------------- -- Note: mutexes and cond_variables needed per-task basis are initialized -- in Initialize_TCB and the Storage_Error is handled. Other mutexes (such -- as RTS_Lock, Memory_Lock...) used in RTS is initialized before any -- status change of RTS. Therefore raising Storage_Error in the following -- routines should be able to be handled safely. procedure Initialize_Lock (Prio : System.Any_Priority; L : not null access Lock) is begin if Init_Mutex (L.WO'Access, Prio) = ENOMEM then raise Storage_Error with "Failed to allocate a lock"; end if; end Initialize_Lock; procedure Initialize_Lock (L : not null access RTS_Lock; Level : Lock_Level) is pragma Unreferenced (Level); begin if Init_Mutex (L.all'Access, Any_Priority'Last) = ENOMEM then raise Storage_Error with "Failed to allocate a lock"; end if; end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- procedure Finalize_Lock (L : not null access Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (L.WO'Access); pragma Assert (Result = 0); end Finalize_Lock; procedure Finalize_Lock (L : not null access RTS_Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (L); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : not null access Lock; Ceiling_Violation : out Boolean) is Self : constant pthread_t := pthread_self; Result : int; Policy : aliased int; Ceiling : aliased int; Sched : aliased struct_sched_param; begin Result := pthread_mutex_lock (L.WO'Access); -- The cause of EINVAL is a priority ceiling violation Ceiling_Violation := Result = EINVAL; pragma Assert (Result = 0 or else Ceiling_Violation); -- Workaround bug in QNX on ceiling locks: tasks with priority higher -- than the ceiling priority don't receive EINVAL upon trying to lock. if Result = 0 and then Locking_Policy = 'C' then Result := pthread_getschedparam (Self, Policy'Access, Sched'Access); pragma Assert (Result = 0); Result := pthread_mutex_getprioceiling (L.WO'Access, Ceiling'Access); pragma Assert (Result = 0); -- Ceiling < current priority means Ceiling violation -- (otherwise the current priority == ceiling) if Ceiling < Sched.sched_curpriority then Ceiling_Violation := True; Result := pthread_mutex_unlock (L.WO'Access); pragma Assert (Result = 0); end if; end if; end Write_Lock; procedure Write_Lock (L : not null access RTS_Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_lock (L); pragma Assert (Result = 0); end Write_Lock; procedure Write_Lock (T : Task_Id) is Result : Interfaces.C.int; begin Result := pthread_mutex_lock (T.Common.LL.L'Access); pragma Assert (Result = 0); end Write_Lock; --------------- -- Read_Lock -- --------------- procedure Read_Lock (L : not null access Lock; Ceiling_Violation : out Boolean) is begin Write_Lock (L, Ceiling_Violation); end Read_Lock; ------------ -- Unlock -- ------------ procedure Unlock (L : not null access Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_unlock (L.WO'Access); pragma Assert (Result = 0); end Unlock; procedure Unlock (L : not null access RTS_Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_unlock (L); pragma Assert (Result = 0); end Unlock; procedure Unlock (T : Task_Id) is Result : Interfaces.C.int; begin Result := pthread_mutex_unlock (T.Common.LL.L'Access); pragma Assert (Result = 0); end Unlock; ----------------- -- Set_Ceiling -- ----------------- procedure Set_Ceiling (L : not null access Lock; Prio : System.Any_Priority) is Result : Interfaces.C.int; begin Result := pthread_mutex_setprioceiling (L.WO'Access, To_Target_Priority (Prio), null); pragma Assert (Result = 0); end Set_Ceiling; ----------- -- Sleep -- ----------- procedure Sleep (Self_ID : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : Interfaces.C.int; begin Result := pthread_cond_wait (cond => Self_ID.Common.LL.CV'Access, mutex => Self_ID.Common.LL.L'Access); -- EINTR is not considered a failure pragma Assert (Result = 0 or else Result = EINTR); end Sleep; ----------------- -- Timed_Sleep -- ----------------- -- This is for use within the run-time system, so abort is -- assumed to be already deferred, and the caller should be -- holding its own ATCB lock. procedure Timed_Sleep (Self_ID : Task_Id; Time : Duration; Mode : ST.Delay_Modes; Reason : Task_States; Timedout : out Boolean; Yielded : out Boolean) renames Monotonic.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) renames Monotonic.Timed_Delay; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration renames Monotonic.Monotonic_Clock; ------------------- -- RT_Resolution -- ------------------- function RT_Resolution return Duration renames Monotonic.RT_Resolution; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : Interfaces.C.int; begin Result := pthread_cond_signal (T.Common.LL.CV'Access); pragma Assert (Result = 0); end Wakeup; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is Result : Interfaces.C.int; pragma Unreferenced (Result); begin if Do_Yield then Result := sched_yield; end if; end Yield; ------------------ -- Set_Priority -- ------------------ procedure Set_Priority (T : Task_Id; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is pragma Unreferenced (Loss_Of_Inheritance); Result : Interfaces.C.int; Old : constant System.Any_Priority := T.Common.Current_Priority; begin T.Common.Current_Priority := Prio; Result := pthread_setschedprio (T.Common.LL.Thread, To_Target_Priority (Prio)); pragma Assert (Result = 0); if T.Common.LL.Thread = pthread_self and then Old > Prio then -- When lowering the priority via a pthread_setschedprio, QNX ensures -- that the running thread remains in the head of the FIFO for tne -- new priority. Annex D expects the thread to be requeued so let's -- yield to the other threads of the same priority. Result := sched_yield; pragma Assert (Result = 0); 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 begin Self_ID.Common.LL.Thread := pthread_self; Self_ID.Common.LL.LWP := lwp_self; Specific.Set (Self_ID); if Use_Alternate_Stack then declare Stack : aliased stack_t; Result : Interfaces.C.int; begin Stack.ss_sp := Self_ID.Common.Task_Alternate_Stack; Stack.ss_size := Alternate_Stack_Size; Stack.ss_flags := 0; Result := sigaltstack (Stack'Access, null); pragma Assert (Result = 0); end; end if; end Enter_Task; ------------------- -- Is_Valid_Task -- ------------------- function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task; ----------------------------- -- Register_Foreign_Thread -- ----------------------------- function Register_Foreign_Thread return Task_Id is begin if Is_Valid_Task then return Self; else return Register_Foreign_Thread (pthread_self); end if; end Register_Foreign_Thread; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is Result : Interfaces.C.int; Cond_Attr : aliased pthread_condattr_t; begin -- Give the task a unique serial number Self_ID.Serial_Number := Next_Serial_Number; Next_Serial_Number := Next_Serial_Number + 1; pragma Assert (Next_Serial_Number /= 0); Result := Init_Mutex (Self_ID.Common.LL.L'Access, Any_Priority'Last); pragma Assert (Result = 0); if Result /= 0 then Succeeded := False; return; end if; Result := pthread_condattr_init (Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = 0 then Result := GNAT_pthread_condattr_setup (Cond_Attr'Access); pragma Assert (Result = 0); Result := pthread_cond_init (Self_ID.Common.LL.CV'Access, Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); end if; if Result = 0 then Succeeded := True; else Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access); pragma Assert (Result = 0); Succeeded := False; end if; Result := pthread_condattr_destroy (Cond_Attr'Access); pragma Assert (Result = 0); end Initialize_TCB; ----------------- -- Create_Task -- ----------------- procedure Create_Task (T : Task_Id; Wrapper : System.Address; Stack_Size : System.Parameters.Size_Type; Priority : System.Any_Priority; Succeeded : out Boolean) is Attributes : aliased pthread_attr_t; Adjusted_Stack_Size : Interfaces.C.size_t; Page_Size : constant Interfaces.C.size_t := Interfaces.C.size_t (Get_Page_Size); Sched_Param : aliased struct_sched_param; Result : Interfaces.C.int; Priority_Specific_Policy : constant Character := Get_Policy (Priority); -- Upper case first character of the policy name corresponding to the -- task as set by a Priority_Specific_Dispatching pragma. function Thread_Body_Access is new Ada.Unchecked_Conversion (System.Address, Thread_Body); begin Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size + Alternate_Stack_Size); if Stack_Base_Available then -- If Stack Checking is supported then allocate 2 additional pages: -- In the worst case, stack is allocated at something like -- N * Get_Page_Size - epsilon, we need to add the size for 2 pages -- to be sure the effective stack size is greater than what -- has been asked. Adjusted_Stack_Size := Adjusted_Stack_Size + 2 * Page_Size; end if; -- Round stack size as this is required by some OSes (Darwin) Adjusted_Stack_Size := Adjusted_Stack_Size + Page_Size - 1; Adjusted_Stack_Size := Adjusted_Stack_Size - Adjusted_Stack_Size mod Page_Size; Result := pthread_attr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Succeeded := False; return; end if; Result := pthread_attr_setdetachstate (Attributes'Access, PTHREAD_CREATE_DETACHED); pragma Assert (Result = 0); Result := pthread_attr_setstacksize (Attributes'Access, Adjusted_Stack_Size); pragma Assert (Result = 0); -- Set thread priority T.Common.Current_Priority := Priority; Sched_Param.sched_priority := To_Target_Priority (Priority); Result := pthread_attr_setinheritsched (Attributes'Access, PTHREAD_EXPLICIT_SCHED); pragma Assert (Result = 0); Result := pthread_attr_setschedparam (Attributes'Access, Sched_Param'Access); pragma Assert (Result = 0); if Time_Slice_Supported and then (Dispatching_Policy = 'R' or else Priority_Specific_Policy = 'R' or else Time_Slice_Val > 0) then Result := pthread_attr_setschedpolicy (Attributes'Access, SCHED_RR); elsif Dispatching_Policy = 'F' or else Priority_Specific_Policy = 'F' or else Time_Slice_Val = 0 then Result := pthread_attr_setschedpolicy (Attributes'Access, SCHED_FIFO); else Result := pthread_attr_setschedpolicy (Attributes'Access, SCHED_OTHER); end if; pragma Assert (Result = 0); -- Since the initial signal mask of a thread is inherited from the -- creator, and the Environment task has all its signals masked, we -- do not need to manipulate caller's signal mask at this point. -- All tasks in RTS will have All_Tasks_Mask initially. -- Note: the use of Unrestricted_Access in the following call is needed -- because otherwise we have an error of getting a access-to-volatile -- value which points to a non-volatile object. But in this case it is -- safe to do this, since we know we have no problems with aliasing and -- Unrestricted_Access bypasses this check. Result := pthread_create (T.Common.LL.Thread'Unrestricted_Access, Attributes'Access, Thread_Body_Access (Wrapper), To_Address (T)); pragma Assert (Result = 0 or else Result = EAGAIN); Succeeded := Result = 0; Result := pthread_attr_destroy (Attributes'Access); pragma Assert (Result = 0); end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_Id) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (T.Common.LL.L'Access); pragma Assert (Result = 0); Result := pthread_cond_destroy (T.Common.LL.CV'Access); pragma Assert (Result = 0); if T.Known_Tasks_Index /= -1 then Known_Tasks (T.Known_Tasks_Index) := null; end if; ATCB_Allocation.Free_ATCB (T); end Finalize_TCB; --------------- -- Exit_Task -- --------------- procedure Exit_Task is begin -- Mark this task as unknown, so that if Self is called, it won't -- return a dangling pointer. Specific.Set (null); end Exit_Task; ---------------- -- Abort_Task -- ---------------- procedure Abort_Task (T : Task_Id) is Result : Interfaces.C.int; begin if Abort_Handler_Installed then Result := pthread_kill (T.Common.LL.Thread, Signal (System.Interrupt_Management.Abort_Task_Interrupt)); pragma Assert (Result = 0); end if; end Abort_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (S : in out Suspension_Object) is Mutex_Attr : aliased pthread_mutexattr_t; Cond_Attr : aliased pthread_condattr_t; Result : Interfaces.C.int; begin -- Initialize internal state (always to False (RM D.10 (6))) S.State := False; S.Waiting := False; -- Initialize internal mutex Result := pthread_mutexattr_init (Mutex_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then Result := pthread_mutexattr_destroy (Mutex_Attr'Access); pragma Assert (Result = 0); raise Storage_Error; end if; Result := pthread_mutexattr_destroy (Mutex_Attr'Access); pragma Assert (Result = 0); -- Initialize internal condition variable Result := pthread_condattr_init (Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Result := pthread_mutex_destroy (S.L'Access); pragma Assert (Result = 0); -- Storage_Error is propagated as intended if the allocation of the -- underlying OS entities fails. raise Storage_Error; else Result := GNAT_pthread_condattr_setup (Cond_Attr'Access); pragma Assert (Result = 0); end if; Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Result := pthread_mutex_destroy (S.L'Access); pragma Assert (Result = 0); Result := pthread_condattr_destroy (Cond_Attr'Access); pragma Assert (Result = 0); -- Storage_Error is propagated as intended if the allocation of the -- underlying OS entities fails. raise Storage_Error; end if; Result := pthread_condattr_destroy (Cond_Attr'Access); pragma Assert (Result = 0); end Initialize; -------------- -- Finalize -- -------------- procedure Finalize (S : in out Suspension_Object) is Result : Interfaces.C.int; begin -- Destroy internal mutex Result := pthread_mutex_destroy (S.L'Access); pragma Assert (Result = 0); -- Destroy internal condition variable Result := pthread_cond_destroy (S.CV'Access); pragma Assert (Result = 0); end Finalize; ------------------- -- Current_State -- ------------------- function Current_State (S : Suspension_Object) return Boolean is begin -- We do not want to use lock on this read operation. State is marked -- as Atomic so that we ensure that the value retrieved is correct. return S.State; end Current_State; --------------- -- Set_False -- --------------- procedure Set_False (S : in out Suspension_Object) is Result : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); S.State := False; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; end Set_False; -------------- -- Set_True -- -------------- procedure Set_True (S : in out Suspension_Object) is Result : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); -- If there is already a task waiting on this suspension object then -- we resume it, leaving the state of the suspension object to False, -- as it is specified in (RM D.10(9)). Otherwise, it just leaves -- the state to True. if S.Waiting then S.Waiting := False; S.State := False; Result := pthread_cond_signal (S.CV'Access); pragma Assert (Result = 0); else S.State := True; end if; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; end Set_True; ------------------------ -- Suspend_Until_True -- ------------------------ procedure Suspend_Until_True (S : in out Suspension_Object) is Result : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); if S.Waiting then -- Program_Error must be raised upon calling Suspend_Until_True -- if another task is already waiting on that suspension object -- (RM D.10(10)). Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; raise Program_Error; else -- Suspend the task if the state is False. Otherwise, the task -- continues its execution, and the state of the suspension object -- is set to False (ARM D.10 par. 9). if S.State then S.State := False; else S.Waiting := True; loop -- Loop in case pthread_cond_wait returns earlier than expected -- (e.g. in case of EINTR caused by a signal). Result := pthread_cond_wait (S.CV'Access, S.L'Access); pragma Assert (Result = 0 or else Result = EINTR); exit when not S.Waiting; end loop; end if; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; end if; end Suspend_Until_True; ---------------- -- Check_Exit -- ---------------- -- Dummy version function Check_Exit (Self_ID : ST.Task_Id) return Boolean is pragma Unreferenced (Self_ID); begin return True; end Check_Exit; -------------------- -- Check_No_Locks -- -------------------- function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is pragma Unreferenced (Self_ID); begin return True; end Check_No_Locks; ---------------------- -- Environment_Task -- ---------------------- function Environment_Task return Task_Id is begin return Environment_Task_Id; end Environment_Task; -------------- -- Lock_RTS -- -------------- procedure Lock_RTS is begin Write_Lock (Single_RTS_Lock'Access); end Lock_RTS; ---------------- -- Unlock_RTS -- ---------------- procedure Unlock_RTS is begin Unlock (Single_RTS_Lock'Access); end Unlock_RTS; ------------------ -- Suspend_Task -- ------------------ function Suspend_Task (T : ST.Task_Id; Thread_Self : Thread_Id) return Boolean is pragma Unreferenced (T, Thread_Self); begin return False; end Suspend_Task; ----------------- -- Resume_Task -- ----------------- function Resume_Task (T : ST.Task_Id; Thread_Self : Thread_Id) return Boolean is pragma Unreferenced (T, Thread_Self); begin return False; end Resume_Task; -------------------- -- Stop_All_Tasks -- -------------------- procedure Stop_All_Tasks is begin null; end Stop_All_Tasks; --------------- -- Stop_Task -- --------------- function Stop_Task (T : ST.Task_Id) return Boolean is pragma Unreferenced (T); begin return False; end Stop_Task; ------------------- -- Continue_Task -- ------------------- function Continue_Task (T : ST.Task_Id) return Boolean is pragma Unreferenced (T); begin return False; end Continue_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : Task_Id) is act : aliased struct_sigaction; old_act : aliased struct_sigaction; Tmp_Set : aliased sigset_t; Result : Interfaces.C.int; function State (Int : System.Interrupt_Management.Interrupt_ID) return Character; pragma Import (C, State, "__gnat_get_interrupt_state"); -- Get interrupt state. Defined in a-init.c -- The input argument is the interrupt number, -- and the result is one of the following: Default : constant Character := 's'; -- 'n' this interrupt not set by any Interrupt_State pragma -- 'u' Interrupt_State pragma set state to User -- 'r' Interrupt_State pragma set state to Runtime -- 's' Interrupt_State pragma set state to System (use "default" -- system handler) begin Environment_Task_Id := Environment_Task; Interrupt_Management.Initialize; -- Prepare the set of signals that should unblocked in all tasks Result := sigemptyset (Unblocked_Signal_Mask'Access); pragma Assert (Result = 0); for J in Interrupt_Management.Interrupt_ID loop if System.Interrupt_Management.Keep_Unmasked (J) then Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J)); pragma Assert (Result = 0); end if; end loop; -- Initialize the lock used to synchronize chain of all ATCBs Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); Specific.Initialize (Environment_Task); if Use_Alternate_Stack then Environment_Task.Common.Task_Alternate_Stack := Alternate_Stack'Address; end if; -- Make environment task known here because it doesn't go through -- Activate_Tasks, which does it for all other tasks. Known_Tasks (Known_Tasks'First) := Environment_Task; Environment_Task.Known_Tasks_Index := Known_Tasks'First; Enter_Task (Environment_Task); if State (System.Interrupt_Management.Abort_Task_Interrupt) /= Default then act.sa_flags := 0; act.sa_handler := Abort_Handler'Address; Result := sigemptyset (Tmp_Set'Access); pragma Assert (Result = 0); act.sa_mask := Tmp_Set; Result := sigaction (Signal (System.Interrupt_Management.Abort_Task_Interrupt), act'Unchecked_Access, old_act'Unchecked_Access); pragma Assert (Result = 0); Abort_Handler_Installed := True; end if; end Initialize; ----------------------- -- Set_Task_Affinity -- ----------------------- procedure Set_Task_Affinity (T : ST.Task_Id) is pragma Unreferenced (T); begin -- Setting task affinity is not supported by the underlying system null; end Set_Task_Affinity; end System.Task_Primitives.Operations;