app.h revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
* Copyright (C) 1999-2001, 2004-2007, 2009, 2013-2016 Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
/* $Id: app.h,v 1.11 2009/09/02 23:48:03 tbox Exp $ */
#ifndef ISC_APP_H
#define ISC_APP_H 1
/*****
***** Module Info
*****/
* \brief ISC Application Support
*
* Dealing with program termination can be difficult, especially in a
* multithreaded program. The routines in this module help coordinate
* the shutdown process. They are used as follows by the initial (main)
* thread of the application:
*
*\li isc_app_start(); Call very early in main(), before
* any other threads have been created.
*
*\li isc_app_run(); This will post any on-run events,
* and then block until application
* shutdown is requested. A shutdown
* request is made by calling
* isc_app_shutdown(), or by sending
* SIGINT or SIGTERM to the process.
* After isc_app_run() returns, the
* application should shutdown itself.
*
*\li isc_app_finish(); Call very late in main().
*
* Applications that want to use SIGHUP/isc_app_reload() to trigger reloading
* should check the result of isc_app_run() and call the reload routine if
* the result is ISC_R_RELOAD. They should then call isc_app_run() again
* to resume waiting for reload or termination.
*
* Use of this module is not required. In particular, isc_app_start() is
* NOT an ISC library initialization routine.
*
* This module also supports per-thread 'application contexts'. With this
* mode, a thread-based application will have a separate context, in which
* it uses other ISC library services such as tasks or timers. Signals are
* not caught in this mode, so that the application can handle the signals
* in its preferred way.
*
* \li MP:
* Clients must ensure that isc_app_start(), isc_app_run(), and
* isc_app_finish() are called at most once. isc_app_shutdown()
* is safe to use by any thread (provided isc_app_start() has been
* called previously).
*
* The same note applies to isc_app_ctxXXX() functions, but in this case
* it's a per-thread restriction. For example, a thread with an
* application context must ensure that isc_app_ctxstart() with the
* context is called at most once.
*
* \li Reliability:
* No anticipated impact.
*
* \li Resources:
* None.
*
* \li Security:
* No anticipated impact.
*
* \li Standards:
* None.
*/
#include <isc/eventclass.h>
/***
*** Types
***/
typedef isc_event_t isc_appevent_t;
#define ISC_APPEVENT_FIRSTEVENT (ISC_EVENTCLASS_APP + 0)
/*%
* app module methods. Only app driver implementations use this structure.
* Other clients should use the top-level interfaces (i.e., isc_app_xxx
* functions). magic must be ISCAPI_APPMETHODS_MAGIC.
*/
typedef struct isc_appmethods {
void *arg);
/*%
* This structure is actually just the common prefix of an application context
* implementation's version of an isc_appctx_t.
* \brief
* Direct use of this structure by clients is forbidden. app implementations
* may change the structure. 'magic' must be ISCAPI_APPCTX_MAGIC for any
* of the isc_app_ routines to work. app implementations must maintain
* all app context invariants.
*/
struct isc_appctx {
unsigned int impmagic;
unsigned int magic;
};
#define ISCAPI_APPCTX_VALID(c) ((c) != NULL && \
(c)->magic == ISCAPI_APPCTX_MAGIC)
isc_app_start(void);
/*!<
* \brief Start an ISC library application.
*
* Notes:
* This call should be made before any other ISC library call, and as
* close to the beginning of the application as possible.
*
* Requires:
*\li 'ctx' is a valid application context (for app_ctxstart()).
*/
void *arg);
/*!<
* \brief Request delivery of an event when the application is run.
*
* Requires:
*\li isc_app_start() has been called.
*\li 'ctx' is a valid application context (for app_ctxonrun()).
*
* Returns:
* ISC_R_SUCCESS
* ISC_R_NOMEMORY
*/
isc_app_run(void);
/*!<
* \brief Run an ISC library application.
*
* Notes:
*\li The caller (typically the initial thread of an application) will
* block until shutdown is requested. When the call returns, the
* caller should start shutting down the application.
*
* Requires:
*\li isc_app_[ctx]start() has been called.
*
* Ensures:
*\li Any events requested via isc_app_onrun() will have been posted (in
* FIFO order) before isc_app_run() blocks.
*\li 'ctx' is a valid application context (for app_ctxrun()).
*
* Returns:
*\li ISC_R_SUCCESS Shutdown has been requested.
*\li ISC_R_RELOAD Reload has been requested.
*/
isc_app_isrunning(void);
/*!<
* \brief Return if the ISC library application is running.
*
* Returns:
*\li ISC_TRUE App is running.
*\li ISC_FALSE App is not running.
*/
isc_app_shutdown(void);
/*!<
* \brief Request application shutdown.
*
* Notes:
*\li It is safe to call isc_app_shutdown() multiple times. Shutdown will
* only be triggered once.
*
* Requires:
*\li isc_app_[ctx]run() has been called.
*\li 'ctx' is a valid application context (for app_ctxshutdown()).
*
* Returns:
*\li ISC_R_SUCCESS
*\li ISC_R_UNEXPECTED
*/
/*!<
* \brief This has the same behavior as isc_app_ctxsuspend().
*/
isc_app_reload(void);
/*!<
* \brief Request application reload.
*
* Requires:
*\li isc_app_run() has been called.
*
* Returns:
*\li ISC_R_SUCCESS
*\li ISC_R_UNEXPECTED
*/
void
void
isc_app_finish(void);
/*!<
* \brief Finish an ISC library application.
*
* Notes:
*\li This call should be made at or near the end of main().
*
* Requires:
*\li isc_app_start() has been called.
*\li 'ctx' is a valid application context (for app_ctxfinish()).
*
* Ensures:
*\li Any resources allocated by isc_app_start() have been released.
*/
void
isc_app_block(void);
/*!<
* \brief Indicate that a blocking operation will be performed.
*
* Notes:
*\li If a blocking operation is in process, a call to isc_app_shutdown()
* or an external signal will abort the program, rather than allowing
* clean shutdown. This is primarily useful for reading user input.
*
* Requires:
* \li isc_app_start() has been called.
* \li No other blocking operations are in progress.
*/
void
isc_app_unblock(void);
/*!<
* \brief Indicate that a blocking operation is complete.
*
* Notes:
* \li When a blocking operation has completed, return the program to a
* state where a call to isc_app_shutdown() or an external signal will
* shutdown normally.
*
* Requires:
* \li isc_app_start() has been called.
* \li isc_app_block() has been called by the same thread.
*/
/*!<
* \brief Create an application context.
*
* Requires:
*\li 'mctx' is a valid memory context.
*\li 'ctxp' != NULL && *ctxp == NULL.
*/
void
/*!<
* \brief Destroy an application context.
*
* Requires:
*\li '*ctxp' is a valid application context.
*
* Ensures:
*\li *ctxp == NULL.
*/
void
/*!<
* \brief Associate a task manager with an application context.
*
* This must be done before running tasks within the application context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'taskmgr' is a valid task manager.
*/
void
/*!<
* \brief Associate a socket manager with an application context.
*
* This must be done before handling socket events within the application
* context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'socketmgr' is a valid socket manager.
*/
void
/*!<
* \brief Associate a socket timer with an application context.
*
* This must be done before handling timer events within the application
* context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'timermgr' is a valid timer manager.
*/
/*%<
* See isc_appctx_create() above.
*/
typedef isc_result_t
/*%<
* Register a new application implementation and add it to the list of
* supported implementations. This function must be called when a different
* event library is used than the one contained in the ISC library.
*/
isc__app_register(void);
/*%<
* A short cut function that specifies the application module in the ISC
* library for isc_app_register(). An application that uses the ISC library
* usually do not have to care about this function: it would call
* isc_lib_register(), which internally calls this function.
*/
#endif /* ISC_APP_H */