|
111
|
1 ------------------------------------------------------------------------------
|
|
|
2 -- --
|
|
|
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
|
|
|
4 -- --
|
|
|
5 -- S Y S T E M . T A S K I N G . U T I L I T I E S --
|
|
|
6 -- --
|
|
|
7 -- S p e c --
|
|
|
8 -- --
|
|
131
|
9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
|
|
111
|
10 -- --
|
|
|
11 -- GNARL is free software; you can redistribute it and/or modify it under --
|
|
|
12 -- terms of the GNU General Public License as published by the Free Soft- --
|
|
|
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
|
|
|
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
|
|
|
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
|
|
|
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
|
|
|
17 -- --
|
|
|
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
|
|
|
19 -- additional permissions described in the GCC Runtime Library Exception, --
|
|
|
20 -- version 3.1, as published by the Free Software Foundation. --
|
|
|
21 -- --
|
|
|
22 -- You should have received a copy of the GNU General Public License and --
|
|
|
23 -- a copy of the GCC Runtime Library Exception along with this program; --
|
|
|
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
|
|
|
25 -- <http://www.gnu.org/licenses/>. --
|
|
|
26 -- --
|
|
|
27 -- GNARL was developed by the GNARL team at Florida State University. --
|
|
|
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
|
|
|
29 -- --
|
|
|
30 ------------------------------------------------------------------------------
|
|
|
31
|
|
|
32 -- This package provides RTS Internal Declarations.
|
|
|
33 -- These declarations are not part of the GNARLI
|
|
|
34
|
|
|
35 with Ada.Unchecked_Conversion;
|
|
|
36 with System.Task_Primitives;
|
|
|
37
|
|
|
38 package System.Tasking.Utilities is
|
|
|
39
|
|
|
40 function ATCB_To_Address is new
|
|
|
41 Ada.Unchecked_Conversion (Task_Id, System.Task_Primitives.Task_Address);
|
|
|
42
|
|
|
43 ---------------------------------
|
|
|
44 -- Task_Stage Related routines --
|
|
|
45 ---------------------------------
|
|
|
46
|
|
|
47 function Make_Independent return Boolean;
|
|
|
48 -- Move the current task to the outermost level (level 2) of the master
|
|
|
49 -- hierarchy of the environment task. That is one level further out
|
|
|
50 -- than normal tasks defined in library-level packages (level 3). The
|
|
|
51 -- environment task will wait for level 3 tasks to terminate normally,
|
|
|
52 -- then it will abort all the level 2 tasks. See Finalize_Global_Tasks
|
|
|
53 -- procedure for more information.
|
|
|
54 --
|
|
|
55 -- This is a dangerous operation, and should never be used on nested tasks
|
|
|
56 -- or tasks that depend on any objects that might be finalized earlier than
|
|
131
|
57 -- the termination of the environment task. It is primarily for internal
|
|
|
58 -- use by the GNARL, to prevent such internal server tasks from preventing
|
|
|
59 -- a partition from terminating.
|
|
111
|
60 --
|
|
|
61 -- Also note that the run time assumes that the parent of an independent
|
|
|
62 -- task is the environment task. If this is not the case, Make_Independent
|
|
|
63 -- will change the task's parent. This assumption is particularly
|
|
|
64 -- important for master level completion and for the computation of
|
|
|
65 -- Independent_Task_Count.
|
|
|
66 --
|
|
|
67 -- NOTE WELL: Make_Independent should be called before the task reaches its
|
|
|
68 -- "begin", like this:
|
|
|
69 --
|
|
|
70 -- task body Some_Independent_Task is
|
|
|
71 -- ...
|
|
|
72 -- Ignore : constant Boolean := Make_Independent;
|
|
|
73 -- ...
|
|
|
74 -- begin
|
|
|
75 --
|
|
|
76 -- The return value is meaningless; the only reason this is a function is
|
|
|
77 -- to get around the Ada limitation that makes a procedure call
|
|
|
78 -- syntactically illegal before the "begin".
|
|
|
79 --
|
|
|
80 -- Calling it before "begin" ensures that the call completes before the
|
|
|
81 -- activating task can proceed. This is important for preventing race
|
|
|
82 -- conditions. For example, if the environment task reaches
|
|
|
83 -- Finalize_Global_Tasks before some task has finished Make_Independent,
|
|
|
84 -- the program can hang.
|
|
|
85 --
|
|
|
86 -- Note also that if a package declares independent tasks, it should not
|
|
|
87 -- initialize its package-body data after "begin" of the package, because
|
|
|
88 -- that's where the tasks are activated. Initializing such data before the
|
|
|
89 -- task activation helps prevent the tasks from accessing uninitialized
|
|
|
90 -- data.
|
|
|
91
|
|
|
92 Independent_Task_Count : Natural := 0;
|
|
|
93 -- Number of independent tasks. This counter is incremented each time
|
|
|
94 -- Make_Independent is called. Note that if a server task terminates,
|
|
|
95 -- this counter will not be decremented. Since Make_Independent locks
|
|
|
96 -- the environment task (because every independent task depends on it),
|
|
|
97 -- this counter is protected by the environment task's lock.
|
|
|
98
|
|
|
99 ---------------------------------
|
|
|
100 -- Task Abort Related Routines --
|
|
|
101 ---------------------------------
|
|
|
102
|
|
|
103 procedure Cancel_Queued_Entry_Calls (T : Task_Id);
|
|
|
104 -- Cancel any entry calls queued on target task.
|
|
|
105 -- Call this while holding T's lock (or RTS_Lock in Single_Lock mode).
|
|
|
106
|
|
|
107 procedure Exit_One_ATC_Level (Self_ID : Task_Id);
|
|
|
108 pragma Inline (Exit_One_ATC_Level);
|
|
|
109 -- Call only with abort deferred and holding lock of Self_ID.
|
|
|
110 -- This is a bit of common code for all entry calls.
|
|
|
111 -- The effect is to exit one level of ATC nesting.
|
|
|
112
|
|
|
113 procedure Abort_One_Task (Self_ID : Task_Id; T : Task_Id);
|
|
|
114 -- Similar to Locked_Abort_To_Level (Self_ID, T, 0), but:
|
|
|
115 -- (1) caller should be holding no locks
|
|
|
116 -- (2) may be called for tasks that have not yet been activated
|
|
|
117 -- (3) always aborts whole task
|
|
|
118
|
|
|
119 procedure Abort_Tasks (Tasks : Task_List);
|
|
|
120 -- Abort_Tasks is called to initiate abort, however, the actual
|
|
|
121 -- aborting is done by aborted task by means of Abort_Handler
|
|
|
122
|
|
|
123 procedure Make_Passive (Self_ID : Task_Id; Task_Completed : Boolean);
|
|
|
124 -- Update counts to indicate current task is either terminated or
|
|
|
125 -- accepting on a terminate alternative. Call holding no locks except
|
|
|
126 -- Global_Task_Lock when calling from Terminate_Task, and RTS_Lock when
|
|
|
127 -- Single_Lock is True.
|
|
|
128
|
|
|
129 end System.Tasking.Utilities;
|
