mirror of
https://gitlab.isc.org/isc-projects/bind9
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17aed2f895
The isc_task_purgerange() was walking through all events on the task to find a matching task. Instead use the ISC_LINK_LINKED to find whether the event is active. Cleanup the related isc_task_unsend() and isc_task_unsendrange() functions that were not used anywhere.
607 lines
14 KiB
C
607 lines
14 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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#pragma once
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/*****
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***** Module Info
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*****/
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/*! \file isc/task.h
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* \brief The task system provides a lightweight execution context, which is
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* basically an event queue.
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*
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* When a task's event queue is non-empty, the
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* task is runnable. A small work crew of threads, typically one per CPU,
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* execute runnable tasks by dispatching the events on the tasks' event
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* queues. Context switching between tasks is fast.
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*
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* \li MP:
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* The module ensures appropriate synchronization of data structures it
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* creates and manipulates.
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* The caller must ensure that isc_taskmgr_destroy() is called only
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* once for a given manager.
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*
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* \li Reliability:
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* No anticipated impact.
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*
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* \li Resources:
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* TBS
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*
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* \li Security:
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* No anticipated impact.
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*
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* \li Standards:
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* None.
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*
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* \section purge Purging and Unsending
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*
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* Events which have been queued for a task but not delivered may be removed
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* from the task's event queue by purging or unsending.
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*
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* With both types, the caller specifies a matching pattern that selects
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* events based upon their sender, type, and tag.
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*
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* Purging calls isc_event_free() on the matching events.
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*
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*/
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/***
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*** Imports.
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***/
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#include <stdbool.h>
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#include <isc/eventclass.h>
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#include <isc/lang.h>
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#include <isc/netmgr.h>
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#include <isc/stdtime.h>
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#include <isc/types.h>
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#define ISC_TASKEVENT_FIRSTEVENT (ISC_EVENTCLASS_TASK + 0)
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#define ISC_TASKEVENT_SHUTDOWN (ISC_EVENTCLASS_TASK + 1)
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#define ISC_TASKEVENT_TEST (ISC_EVENTCLASS_TASK + 1)
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#define ISC_TASKEVENT_LASTEVENT (ISC_EVENTCLASS_TASK + 65535)
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/*****
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***** Tasks.
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*****/
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ISC_LANG_BEGINDECLS
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/***
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*** Types
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***/
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typedef enum {
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isc_taskmgrmode_normal = 0,
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isc_taskmgrmode_privileged
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} isc_taskmgrmode_t;
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isc_result_t
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isc_task_create(isc_taskmgr_t *manager, unsigned int quantum,
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isc_task_t **taskp);
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isc_result_t
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isc_task_create_bound(isc_taskmgr_t *manager, unsigned int quantum,
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isc_task_t **taskp, int tid);
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/*%<
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* Create a task, optionally bound to a particular tid.
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*
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* Notes:
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*
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*\li If 'quantum' is non-zero, then only that many events can be dispatched
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* before the task must yield to other tasks waiting to execute. If
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* quantum is zero, then the default quantum of the task manager will
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* be used.
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*
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*\li The 'quantum' option may be removed from isc_task_create() in the
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* future. If this happens, isc_task_getquantum() and
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* isc_task_setquantum() will be provided.
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*
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* Requires:
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*
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*\li 'manager' is a valid task manager.
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*
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*\li taskp != NULL && *taskp == NULL
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*
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* Ensures:
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*
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*\li On success, '*taskp' is bound to the new task.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS
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*\li #ISC_R_NOMEMORY
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*\li #ISC_R_UNEXPECTED
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*\li #ISC_R_SHUTTINGDOWN
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*/
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void
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isc_task_ready(isc_task_t *task);
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/*%<
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* Enqueue the task onto netmgr queue.
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*/
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isc_result_t
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isc_task_run(isc_task_t *task);
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/*%<
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* Run all the queued events for the 'task', returning
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* when the queue is empty or the number of events executed
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* exceeds the 'quantum' specified when the task was created.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS
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*\li #ISC_R_QUOTA
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*/
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void
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isc_task_attach(isc_task_t *source, isc_task_t **targetp);
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/*%<
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* Attach *targetp to source.
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*
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* Requires:
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*
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*\li 'source' is a valid task.
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*
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*\li 'targetp' points to a NULL isc_task_t *.
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*
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* Ensures:
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*
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*\li *targetp is attached to source.
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*/
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void
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isc_task_detach(isc_task_t **taskp);
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/*%<
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* Detach *taskp from its task.
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*
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* Requires:
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*
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*\li '*taskp' is a valid task.
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*
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* Ensures:
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*
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*\li *taskp is NULL.
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*
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*\li If '*taskp' is the last reference to the task, the task is idle (has
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* an empty event queue), and has not been shutdown, the task will be
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* shutdown.
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*
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*\li If '*taskp' is the last reference to the task and
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* the task has been shutdown,
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* all resources used by the task will be freed.
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*/
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void
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isc_task_send(isc_task_t *task, isc_event_t **eventp);
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void
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isc_task_sendto(isc_task_t *task, isc_event_t **eventp, int c);
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/*%<
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* Send '*event' to 'task', if task is idle try starting it on cpu 'c'
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* If 'c' is smaller than 0 then cpu is selected randomly.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*\li eventp != NULL && *eventp != NULL.
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*
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* Ensures:
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*
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*\li *eventp == NULL.
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*/
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void
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isc_task_sendtoanddetach(isc_task_t **taskp, isc_event_t **eventp, int c);
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void
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isc_task_sendanddetach(isc_task_t **taskp, isc_event_t **eventp);
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/*%<
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* Send '*event' to '*taskp' and then detach '*taskp' from its
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* task. If task is idle try starting it on cpu 'c'
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* If 'c' is smaller than 0 then cpu is selected randomly.
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*
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* Requires:
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*
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*\li '*taskp' is a valid task.
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*\li eventp != NULL && *eventp != NULL.
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*
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* Ensures:
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*
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*\li *eventp == NULL.
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*
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*\li *taskp == NULL.
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*
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*\li If '*taskp' is the last reference to the task, the task is
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* idle (has an empty event queue), and has not been shutdown,
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* the task will be shutdown.
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*
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*\li If '*taskp' is the last reference to the task and
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* the task has been shutdown,
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* all resources used by the task will be freed.
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*/
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unsigned int
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isc_task_purgerange(isc_task_t *task, void *sender, isc_eventtype_t first,
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isc_eventtype_t last, void *tag);
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/*%<
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* Purge events from a task's event queue.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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*\li last >= first
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*
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* Ensures:
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*
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*\li Events in the event queue of 'task' whose sender is 'sender', whose
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* type is >= first and <= last, and whose tag is 'tag' will be purged,
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* unless they are marked as unpurgable.
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*
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*\li A sender of NULL will match any sender. A NULL tag matches any
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* tag.
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*
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* Returns:
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*
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*\li The number of events purged.
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*/
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unsigned int
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isc_task_purge(isc_task_t *task, void *sender, isc_eventtype_t type, void *tag);
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/*%<
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* Purge events from a task's event queue.
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*
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* Notes:
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*
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*\li This function is equivalent to
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*
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*\code
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* isc_task_purgerange(task, sender, type, type, tag);
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*\endcode
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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* Ensures:
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*
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*\li Events in the event queue of 'task' whose sender is 'sender', whose
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* type is 'type', and whose tag is 'tag' will be purged, unless they
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* are marked as unpurgable.
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*
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*\li A sender of NULL will match any sender. A NULL tag matches any
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* tag.
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*
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* Returns:
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*
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*\li The number of events purged.
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*/
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bool
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isc_task_purgeevent(isc_task_t *task, isc_event_t *event);
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/*%<
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* Purge 'event' from a task's event queue.
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*
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* XXXRTH: WARNING: This method may be removed before beta.
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*
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* Notes:
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*
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*\li If 'event' is on the task's event queue, it will be purged,
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* unless it is marked as unpurgeable. 'event' does not have to be
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* on the task's event queue; in fact, it can even be an invalid
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* pointer. Purging only occurs if the event is actually on the task's
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* event queue.
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*
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* \li Purging never changes the state of the task.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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* Ensures:
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*
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*\li 'event' is not in the event queue for 'task'.
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*
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* Returns:
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*
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*\li #true The event was purged.
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*\li #false The event was not in the event queue,
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* or was marked unpurgeable.
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*/
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isc_result_t
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isc_task_onshutdown(isc_task_t *task, isc_taskaction_t action, void *arg);
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/*%<
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* Send a shutdown event with action 'action' and argument 'arg' when
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* 'task' is shutdown.
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*
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* Notes:
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*
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*\li Shutdown events are posted in LIFO order.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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*\li 'action' is a valid task action.
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*
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* Ensures:
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*
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*\li When the task is shutdown, shutdown events requested with
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* isc_task_onshutdown() will be appended to the task's event queue.
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*
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS
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*\li #ISC_R_NOMEMORY
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*\li #ISC_R_SHUTTINGDOWN Task is shutting down.
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*/
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void
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isc_task_shutdown(isc_task_t *task);
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/*%<
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* Shutdown 'task'.
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*
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* Notes:
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*
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*\li Shutting down a task causes any shutdown events requested with
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* isc_task_onshutdown() to be posted (in LIFO order). The task
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* moves into a "shutting down" mode which prevents further calls
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* to isc_task_onshutdown().
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*
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*\li Trying to shutdown a task that has already been shutdown has no
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* effect.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*
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* Ensures:
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*
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*\li Any shutdown events requested with isc_task_onshutdown() have been
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* posted (in LIFO order).
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*/
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void
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isc_task_destroy(isc_task_t **taskp);
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/*%<
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* Destroy '*taskp'.
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*
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* Notes:
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*
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*\li This call is equivalent to:
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*
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*\code
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* isc_task_shutdown(*taskp);
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* isc_task_detach(taskp);
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*\endcode
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*
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* Requires:
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*
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* '*taskp' is a valid task.
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*
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* Ensures:
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*
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*\li Any shutdown events requested with isc_task_onshutdown() have been
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* posted (in LIFO order).
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*
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*\li *taskp == NULL
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*
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*\li If '*taskp' is the last reference to the task,
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* all resources used by the task will be freed.
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*/
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void
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isc_task_setname(isc_task_t *task, const char *name, void *tag);
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/*%<
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* Name 'task'.
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*
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* Notes:
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*
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*\li Only the first 15 characters of 'name' will be copied.
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*
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*\li Naming a task is currently only useful for debugging purposes.
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*
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* Requires:
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*
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*\li 'task' is a valid task.
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*/
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const char *
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isc_task_getname(isc_task_t *task);
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/*%<
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* Get the name of 'task', as previously set using isc_task_setname().
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*
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* Notes:
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*\li This function is for debugging purposes only.
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*
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* Requires:
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*\li 'task' is a valid task.
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*
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* Returns:
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*\li A non-NULL pointer to a null-terminated string.
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* If the task has not been named, the string is
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* empty.
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*
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*/
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isc_nm_t *
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isc_task_getnetmgr(isc_task_t *task);
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void *
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isc_task_gettag(isc_task_t *task);
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/*%<
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* Get the tag value for 'task', as previously set using isc_task_settag().
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*
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* Notes:
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*\li This function is for debugging purposes only.
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*
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* Requires:
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*\li 'task' is a valid task.
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*/
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isc_result_t
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isc_task_beginexclusive(isc_task_t *task);
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/*%<
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* Request exclusive access for 'task', which must be the calling
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* task. Waits for any other concurrently executing tasks to finish their
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* current event, and prevents any new events from executing in any of the
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* tasks sharing a task manager with 'task'.
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* It also pauses processing of network events in netmgr if it was provided
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* when taskmgr was created.
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*
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* The exclusive access must be relinquished by calling
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* isc_task_endexclusive() before returning from the current event handler.
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*
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* Requires:
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*\li 'task' is the calling task.
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*
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* Returns:
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*\li #ISC_R_SUCCESS The current task now has exclusive access.
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*\li #ISC_R_LOCKBUSY Another task has already requested exclusive
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* access.
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*/
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void
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isc_task_endexclusive(isc_task_t *task);
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/*%<
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* Relinquish the exclusive access obtained by isc_task_beginexclusive(),
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* allowing other tasks to execute.
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*
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* Requires:
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*\li 'task' is the calling task, and has obtained
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* exclusive access by calling isc_task_spl().
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*/
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bool
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isc_task_exiting(isc_task_t *t);
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/*%<
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* Returns true if the task is in the process of shutting down,
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* false otherwise.
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*
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* Requires:
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*\li 'task' is a valid task.
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*/
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void
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isc_task_setprivilege(isc_task_t *task, bool priv);
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/*%<
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* Set or unset the task's "privileged" flag depending on the value of
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* 'priv'.
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*
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* Under normal circumstances this flag has no effect on the task behavior,
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* but when the task manager has been set to privileged execution mode via
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* isc_taskmgr_setmode(), only tasks with the flag set will be executed,
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* and all other tasks will wait until they're done. Once all privileged
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* tasks have finished executing, the task manager resumes running
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* non-privileged tasks.
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*
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* Requires:
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*\li 'task' is a valid task.
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*/
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bool
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isc_task_getprivilege(isc_task_t *task);
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/*%<
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* Returns the current value of the task's privilege flag.
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*
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* Requires:
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*\li 'task' is a valid task.
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*/
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bool
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isc_task_privileged(isc_task_t *task);
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/*%<
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* Returns true if the task's privilege flag is set *and* the task
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* manager is currently in privileged mode.
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*
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* Requires:
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*\li 'task' is a valid task.
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*/
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/*****
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***** Task Manager.
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*****/
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void
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isc_taskmgr_attach(isc_taskmgr_t *, isc_taskmgr_t **);
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void
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isc_taskmgr_detach(isc_taskmgr_t **);
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/*%<
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* Attach/detach the task manager.
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*/
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void
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isc_taskmgr_setmode(isc_taskmgr_t *manager, isc_taskmgrmode_t mode);
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isc_taskmgrmode_t
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isc_taskmgr_mode(isc_taskmgr_t *manager);
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/*%<
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* Set/get the operating mode of the task manager. Valid modes are:
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*
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*\li isc_taskmgrmode_normal
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*\li isc_taskmgrmode_privileged
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*
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* In privileged execution mode, only tasks that have had the "privilege"
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* flag set via isc_task_setprivilege() can be executed. When all such
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* tasks are complete, non-privileged tasks resume running. The task calling
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* this function should be in task-exclusive mode; the privileged tasks
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|
* will be run after isc_task_endexclusive() is called.
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*
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* Requires:
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*
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*\li 'manager' is a valid task manager.
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*/
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void
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isc_taskmgr_setexcltask(isc_taskmgr_t *mgr, isc_task_t *task);
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/*%<
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|
* Set a task which will be used for all task-exclusive operations.
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|
*
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|
* Requires:
|
|
*\li 'manager' is a valid task manager.
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|
*
|
|
*\li 'task' is a valid task.
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|
*/
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|
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isc_result_t
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|
isc_taskmgr_excltask(isc_taskmgr_t *mgr, isc_task_t **taskp);
|
|
/*%<
|
|
* Attach '*taskp' to the task set by isc_taskmgr_getexcltask().
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|
* This task should be used whenever running in task-exclusive mode,
|
|
* so as to prevent deadlock between two exclusive tasks.
|
|
*
|
|
* Requires:
|
|
*\li 'manager' is a valid task manager.
|
|
*
|
|
*\li taskp != NULL && *taskp == NULL
|
|
*/
|
|
|
|
#ifdef HAVE_LIBXML2
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|
int
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|
isc_taskmgr_renderxml(isc_taskmgr_t *mgr, void *writer0);
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|
#endif /* ifdef HAVE_LIBXML2 */
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|
|
|
#ifdef HAVE_JSON_C
|
|
isc_result_t
|
|
isc_taskmgr_renderjson(isc_taskmgr_t *mgr, void *tasksobj0);
|
|
#endif /* HAVE_JSON_C */
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|
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|
ISC_LANG_ENDDECLS
|