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Edit File: app.h

/* * Copyright (C) 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 https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #ifndef ISC_APP_H #define ISC_APP_H 1 /***** ***** Module Info *****/ /*! \file isc/app.h * \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 <stdbool.h> #include <isc/eventclass.h> #include <isc/lang.h> #include <isc/magic.h> #include <isc/result.h> /*** *** Types ***/ typedef isc_event_t isc_appevent_t; #define ISC_APPEVENT_FIRSTEVENT (ISC_EVENTCLASS_APP + 0) #define ISC_APPEVENT_SHUTDOWN (ISC_EVENTCLASS_APP + 1) #define ISC_APPEVENT_LASTEVENT (ISC_EVENTCLASS_APP + 65535) ISC_LANG_BEGINDECLS isc_result_t isc_app_ctxstart(isc_appctx_t *ctx); isc_result_t 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()). */ isc_result_t isc_app_ctxonrun(isc_appctx_t *ctx, isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action, void *arg); isc_result_t isc_app_onrun(isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action, 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_result_t isc_app_ctxrun(isc_appctx_t *ctx); isc_result_t 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. */ bool isc_app_isrunning(void); /*!< * \brief Return if the ISC library application is running. * * Returns: *\li true App is running. *\li false App is not running. */ void isc_app_ctxshutdown(isc_appctx_t *ctx); void 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 */ void isc_app_ctxsuspend(isc_appctx_t *ctx); /*!< * \brief This has the same behavior as isc_app_ctxsuspend(). */ void 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 isc_app_ctxfinish(isc_appctx_t *ctx); 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. */ isc_result_t isc_appctx_create(isc_mem_t *mctx, isc_appctx_t **ctxp); /*!< * \brief Create an application context. * * Requires: *\li 'mctx' is a valid memory context. *\li 'ctxp' != NULL && *ctxp == NULL. */ void isc_appctx_destroy(isc_appctx_t **ctxp); /*!< * \brief Destroy an application context. * * Requires: *\li '*ctxp' is a valid application context. * * Ensures: *\li *ctxp == NULL. */ ISC_LANG_ENDDECLS #endif /* ISC_APP_H */