/* Unix SMB/CIFS implementation. generalised event loop handling Copyright (C) Andrew Tridgell 2005 Copyright (C) Stefan Metzmacher 2005-2009 Copyright (C) Volker Lendecke 2008 ** NOTE! The following LGPL license applies to the tevent ** library. This does NOT imply that all of Samba is released ** under the LGPL This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, see . */ #ifndef __TEVENT_H__ #define __TEVENT_H__ #include #include #include #include struct tevent_context; struct tevent_ops; struct tevent_fd; struct tevent_timer; struct tevent_immediate; struct tevent_signal; /** * @defgroup tevent The tevent API * * The tevent low-level API * * @todo description * * @{ */ /* event handler types */ typedef void (*tevent_fd_handler_t)(struct tevent_context *ev, struct tevent_fd *fde, uint16_t flags, void *private_data); typedef void (*tevent_fd_close_fn_t)(struct tevent_context *ev, struct tevent_fd *fde, int fd, void *private_data); typedef void (*tevent_timer_handler_t)(struct tevent_context *ev, struct tevent_timer *te, struct timeval current_time, void *private_data); typedef void (*tevent_immediate_handler_t)(struct tevent_context *ctx, struct tevent_immediate *im, void *private_data); typedef void (*tevent_signal_handler_t)(struct tevent_context *ev, struct tevent_signal *se, int signum, int count, void *siginfo, void *private_data); /** * @brief Create a event_context structure. * * This must be the first events call, and all subsequent calls pass this * event_context as the first element. Event handlers also receive this as * their first argument. * * @param[in] mem_ctx The memory context to use. * * @return An allocated tevent context, NULL on error. * * @see tevent_context_init() */ struct tevent_context *tevent_context_init(TALLOC_CTX *mem_ctx); /** * @brief Create a event_context structure and name it. * * This must be the first events call, and all subsequent calls pass this * event_context as the first element. Event handlers also receive this as * their first argument. * * @param[in] mem_ctx The memory context to use. * * @param[in] name The name for the tevent context. * * @return An allocated tevent context, NULL on error. */ struct tevent_context *tevent_context_init_byname(TALLOC_CTX *mem_ctx, const char *name); /** * @brief List available backends. * * @param[in] mem_ctx The memory context to use. * * @return A string vector with a terminating NULL element, NULL * on error. */ const char **tevent_backend_list(TALLOC_CTX *mem_ctx); /** * @brief Set the default tevent backent. * * @param[in] backend The name of the backend to set. */ void tevent_set_default_backend(const char *backend); #if DOXYGEN /** * @brief Add a file descriptor based event. * * If flags contains TEVENT_FD_AUTOCLOSE then the fd will be closed when * the returned fd_event context is freed. * * @param[in] ev The event context to work on. * * @param[in] mem_ctx The talloc memory context to use. * * @param[in] fd The file descriptor to base the event on. * * @param[in] flags * * @param[in] handler The callback handler for the event. * * @param[in] private_data The private data passed to the callback handler. * * @param[in] handler_name The name to identify the callback handler. * * @return The file descriptor based event, NULL on error. * * @todo Document flags */ struct tevent_fd *tevent_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx, int fd, uint16_t flags, tevent_fd_handler_t handler, void *private_data, const char *handler_name); #else struct tevent_fd *_tevent_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx, int fd, uint16_t flags, tevent_fd_handler_t handler, void *private_data, const char *handler_name, const char *location); #define tevent_add_fd(ev, mem_ctx, fd, flags, handler, private_data) \ _tevent_add_fd(ev, mem_ctx, fd, flags, handler, private_data, \ #handler, __location__) #endif struct tevent_timer *_tevent_add_timer(struct tevent_context *ev, TALLOC_CTX *mem_ctx, struct timeval next_event, tevent_timer_handler_t handler, void *private_data, const char *handler_name, const char *location); #define tevent_add_timer(ev, mem_ctx, next_event, handler, private_data) \ _tevent_add_timer(ev, mem_ctx, next_event, handler, private_data, \ #handler, __location__) struct tevent_immediate *_tevent_create_immediate(TALLOC_CTX *mem_ctx, const char *location); #define tevent_create_immediate(mem_ctx) \ _tevent_create_immediate(mem_ctx, __location__) void _tevent_schedule_immediate(struct tevent_immediate *im, struct tevent_context *ctx, tevent_immediate_handler_t handler, void *private_data, const char *handler_name, const char *location); #define tevent_schedule_immediate(im, ctx, handler, private_data) \ _tevent_schedule_immediate(im, ctx, handler, private_data, \ #handler, __location__); struct tevent_signal *_tevent_add_signal(struct tevent_context *ev, TALLOC_CTX *mem_ctx, int signum, int sa_flags, tevent_signal_handler_t handler, void *private_data, const char *handler_name, const char *location); #define tevent_add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data) \ _tevent_add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data, \ #handler, __location__) int _tevent_loop_once(struct tevent_context *ev, const char *location); #define tevent_loop_once(ev) \ _tevent_loop_once(ev, __location__) \ int _tevent_loop_wait(struct tevent_context *ev, const char *location); #define tevent_loop_wait(ev) \ _tevent_loop_wait(ev, __location__) \ void tevent_fd_set_close_fn(struct tevent_fd *fde, tevent_fd_close_fn_t close_fn); void tevent_fd_set_auto_close(struct tevent_fd *fde); uint16_t tevent_fd_get_flags(struct tevent_fd *fde); void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags); bool tevent_signal_support(struct tevent_context *ev); void tevent_set_abort_fn(void (*abort_fn)(const char *reason)); /* bits for file descriptor event flags */ #define TEVENT_FD_READ 1 #define TEVENT_FD_WRITE 2 #define TEVENT_FD_WRITEABLE(fde) \ tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) | TEVENT_FD_WRITE) #define TEVENT_FD_READABLE(fde) \ tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) | TEVENT_FD_READ) #define TEVENT_FD_NOT_WRITEABLE(fde) \ tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) & ~TEVENT_FD_WRITE) #define TEVENT_FD_NOT_READABLE(fde) \ tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) & ~TEVENT_FD_READ) /** * Debug level of tevent */ enum tevent_debug_level { TEVENT_DEBUG_FATAL, TEVENT_DEBUG_ERROR, TEVENT_DEBUG_WARNING, TEVENT_DEBUG_TRACE }; int tevent_set_debug(struct tevent_context *ev, void (*debug)(void *context, enum tevent_debug_level level, const char *fmt, va_list ap) PRINTF_ATTRIBUTE(3,0), void *context); int tevent_set_debug_stderr(struct tevent_context *ev); /** * @} */ /** * @defgroup tevent_request The tevent request functions. * @ingroup tevent * * This represents an async request being processed by callbacks via an event * context. A user can issue for example a write request to a socket, giving * an implementation function the fd, the buffer and the number of bytes to * transfer. The function issuing the request will immediately return without * blocking most likely without having sent anything. The API user then fills * in req->async.fn and req->async.private_data, functions that are called * when the request is finished. * * It is up to the user of the async request to talloc_free it after it has * finished. This can happen while the completion function is called. * * @{ */ /** * An async request moves between the following 4 states: */ enum tevent_req_state { /** * we are creating the request */ TEVENT_REQ_INIT, /** * we are waiting the request to complete */ TEVENT_REQ_IN_PROGRESS, /** * the request is finished */ TEVENT_REQ_DONE, /** * A user error has occurred */ TEVENT_REQ_USER_ERROR, /** * Request timed out */ TEVENT_REQ_TIMED_OUT, /** * No memory in between */ TEVENT_REQ_NO_MEMORY, /** * the request is already received by the caller */ TEVENT_REQ_RECEIVED }; /** * @brief An async request */ struct tevent_req; typedef void (*tevent_req_fn)(struct tevent_req *); void tevent_req_set_callback(struct tevent_req *req, tevent_req_fn fn, void *pvt); void *_tevent_req_callback_data(struct tevent_req *req); #define tevent_req_callback_data(_req, _type) \ talloc_get_type_abort(_tevent_req_callback_data(_req), _type) #define tevent_req_callback_data_void(_req) \ _tevent_req_callback_data(_req) void *_tevent_req_data(struct tevent_req *req); #define tevent_req_data(_req, _type) \ talloc_get_type_abort(_tevent_req_data(_req), _type) typedef char *(*tevent_req_print_fn)(struct tevent_req *, TALLOC_CTX *); /** * @brief This function sets a print function for the given request. * * This function can be used to setup a print function for the given request. * This will be triggered if the tevent_req_print() function was * called on the given request. * * @param[in] req The request to use. * * @param[in] fn A pointer to the print function * * @note This function should only be used for debugging. */ void tevent_req_set_print_fn(struct tevent_req *req, tevent_req_print_fn fn); /** * @brief The default print function for creating debug messages. * * The function should not be used by users of the async API, * but custom print function can use it and append custom text * to the string. * * @param[in] req The request to be printed. * * @param[in] mem_ctx The memory context for the result. * * @return Text representation of request. * */ char *tevent_req_default_print(struct tevent_req *req, TALLOC_CTX *mem_ctx); /** * @brief Print an tevent_req structure in debug messages. * * This function should be used by callers of the async API. * * @param[in] mem_ctx The memory context for the result. * * @param[in] req The request to be printed. * * @return Text representation of request. */ char *tevent_req_print(TALLOC_CTX *mem_ctx, struct tevent_req *req); typedef bool (*tevent_req_cancel_fn)(struct tevent_req *); /** * @brief This function sets a cancel function for the given tevent request. * * This function can be used to setup a cancel function for the given request. * This will be triggered if the tevent_req_cancel() function was * called on the given request. * * @param[in] req The request to use. * * @param[in] fn A pointer to the cancel function. */ void tevent_req_set_cancel_fn(struct tevent_req *req, tevent_req_cancel_fn fn); #ifdef DOXYGEN /** * @brief Try to cancel the given tevent request. * * This function can be used to cancel the given request. * * It is only possible to cancel a request when the implementation * has registered a cancel function via the tevent_req_set_cancel_fn(). * * @param[in] req The request to use. * * @return This function returns true is the request is cancelable, * othererwise false is returned. * * @note Even if the function returns true, the caller need to wait * for the function to complete normally. * Only the _recv() function of the given request indicates * if the request was really canceled. */ bool tevent_req_cancel(struct tevent_req *req); #else bool _tevent_req_cancel(struct tevent_req *req, const char *location); #define tevent_req_cancel(req) \ _tevent_req_cancel(req, __location__) #endif #if DOXYGEN /** * @brief Create an async tevent request. * * The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS. * * @param[in] mem_ctx The memory context for the result. * * @param[in] pstate The private state of the request. * * @param[in] state_size The size of the private state of the request. * * @param[in] type The name of the request. * * @return A new async request. NULL on error. */ struct tevent_req *tevent_req_create(TALLOC_CTX *mem_ctx, void *pstate, size_t state_size, const char *type); #else struct tevent_req *_tevent_req_create(TALLOC_CTX *mem_ctx, void *pstate, size_t state_size, const char *type, const char *location); #define tevent_req_create(_mem_ctx, _pstate, _type) \ _tevent_req_create((_mem_ctx), (_pstate), sizeof(_type), \ #_type, __location__) #endif bool tevent_req_set_endtime(struct tevent_req *req, struct tevent_context *ev, struct timeval endtime); void _tevent_req_notify_callback(struct tevent_req *req, const char *location); #define tevent_req_notify_callback(req) \ _tevent_req_notify_callback(req, __location__) #ifdef DOXYGEN /** * @brief An async request has successfully finished. * * This function is to be used by implementors of async requests. When a * request is successfully finished, this function calls the user's completion * function. * * @param[in] req The finished request. */ void tevent_req_done(struct tevent_req *req); #else void _tevent_req_done(struct tevent_req *req, const char *location); #define tevent_req_done(req) \ _tevent_req_done(req, __location__) #endif #ifdef DOXYGEN /** * @brief An async request has seen an error. * * This function is to be used by implementors of async requests. When a * request can not successfully completed, the implementation should call this * function with the appropriate status code. * * If error is 0 the function returns false and does nothing more. * * @param[in] req The request with an error. * * @param[in] error The error code. * * @return On success true is returned, false if error is 0. * * @code * int error = first_function(); * if (tevent_req_error(req, error)) { * return; * } * * error = second_function(); * if (tevent_req_error(req, error)) { * return; * } * * tevent_req_done(req); * return; * @endcode */ bool tevent_req_error(struct tevent_req *req, uint64_t error); #else bool _tevent_req_error(struct tevent_req *req, uint64_t error, const char *location); #define tevent_req_error(req, error) \ _tevent_req_error(req, error, __location__) #endif #ifdef DOXYGEN /** * @brief Helper function for nomem check. * * Convenience helper to easily check alloc failure within a callback * implementing the next step of an async request. * * @param[in] p The pointer to be checked. * * @param[in] req The request being processed. * * @code * p = talloc(mem_ctx, bla); * if (tevent_req_nomem(p, req)) { * return; * } * @endcode */ bool tevent_req_nomem(const void *p, struct tevent_req *req); #else bool _tevent_req_nomem(const void *p, struct tevent_req *req, const char *location); #define tevent_req_nomem(p, req) \ _tevent_req_nomem(p, req, __location__) #endif /** * @brief Finish a request before the caller had the change to set the callback. * * An implementation of an async request might find that it can either finish * the request without waiting for an external event, or it can't even start * the engine. To present the illusion of a callback to the user of the API, * the implementation can call this helper function which triggers an * immediate timed event. This way the caller can use the same calling * conventions, independent of whether the request was actually deferred. * * @param[in] req The finished request. * * @param[in] ev The tevent_context for the timed event. * * @return The given request will be returned. */ struct tevent_req *tevent_req_post(struct tevent_req *req, struct tevent_context *ev); /** * @brief Check if the given request is still in progress. * * It is typically used by sync wrapper functions. * * This function destroys the attached private data. * * @param[in] req The request to poll. * * @return The boolean form of "is in progress". */ bool tevent_req_is_in_progress(struct tevent_req *req); /** * @brief Actively poll for the given request to finish. * * This function is typically used by sync wrapper functions. * * @param[in] req The request to poll. * * @param[in] ev The tevent_context to be used. * * @return On success true is returned. If a critical error has * happened in the tevent loop layer false is returned. * This is not the return value of the given request! * * @note This should only be used if the given tevent context was created by the * caller, to avoid event loop nesting. * * @code * req = tstream_writev_queue_send(mem_ctx, * ev_ctx, * tstream, * send_queue, * iov, 2); * ok = tevent_req_poll(req, tctx->ev); * rc = tstream_writev_queue_recv(req, &sys_errno); * TALLOC_FREE(req); * @endcode */ bool tevent_req_poll(struct tevent_req *req, struct tevent_context *ev); bool tevent_req_is_error(struct tevent_req *req, enum tevent_req_state *state, uint64_t *error); /** * @brief Use as the last action of a _recv() function. * * This function destroys the attached private data. * * @param[in] req The finished request. */ void tevent_req_received(struct tevent_req *req); struct tevent_req *tevent_wakeup_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, struct timeval wakeup_time); bool tevent_wakeup_recv(struct tevent_req *req); /* @} */ /** * @defgroup tevent_helpers The tevent helper functiions * @ingroup tevent * * @todo description * * @{ */ int tevent_timeval_compare(const struct timeval *tv1, const struct timeval *tv2); struct timeval tevent_timeval_zero(void); struct timeval tevent_timeval_current(void); struct timeval tevent_timeval_set(uint32_t secs, uint32_t usecs); struct timeval tevent_timeval_until(const struct timeval *tv1, const struct timeval *tv2); bool tevent_timeval_is_zero(const struct timeval *tv); struct timeval tevent_timeval_add(const struct timeval *tv, uint32_t secs, uint32_t usecs); struct timeval tevent_timeval_current_ofs(uint32_t secs, uint32_t usecs); /* @} */ /** * @defgroup tevent_queue The tevent queue functions * @ingroup tevent * * @{ */ struct tevent_queue; struct tevent_queue *_tevent_queue_create(TALLOC_CTX *mem_ctx, const char *name, const char *location); #define tevent_queue_create(_mem_ctx, _name) \ _tevent_queue_create((_mem_ctx), (_name), __location__) typedef void (*tevent_queue_trigger_fn_t)(struct tevent_req *req, void *private_data); bool tevent_queue_add(struct tevent_queue *queue, struct tevent_context *ev, struct tevent_req *req, tevent_queue_trigger_fn_t trigger, void *private_data); void tevent_queue_start(struct tevent_queue *queue); void tevent_queue_stop(struct tevent_queue *queue); size_t tevent_queue_length(struct tevent_queue *queue); typedef int (*tevent_nesting_hook)(struct tevent_context *ev, void *private_data, uint32_t level, bool begin, void *stack_ptr, const char *location); #ifdef TEVENT_DEPRECATED #ifndef _DEPRECATED_ #if (__GNUC__ >= 3) && (__GNUC_MINOR__ >= 1 ) #define _DEPRECATED_ __attribute__ ((deprecated)) #else #define _DEPRECATED_ #endif #endif void tevent_loop_allow_nesting(struct tevent_context *ev) _DEPRECATED_; void tevent_loop_set_nesting_hook(struct tevent_context *ev, tevent_nesting_hook hook, void *private_data) _DEPRECATED_; int _tevent_loop_until(struct tevent_context *ev, bool (*finished)(void *private_data), void *private_data, const char *location) _DEPRECATED_; #define tevent_loop_until(ev, finished, private_data) \ _tevent_loop_until(ev, finished, private_data, __location__) #endif int tevent_re_initialise(struct tevent_context *ev); /* @} */ /** * @defgroup tevent_ops The tevent operation functions * @ingroup tevent * * The following structure and registration functions are exclusively * needed for people writing and pluggin a different event engine. * There is nothing useful for normal tevent user in here. * @{ */ struct tevent_ops { /* context init */ int (*context_init)(struct tevent_context *ev); /* fd_event functions */ struct tevent_fd *(*add_fd)(struct tevent_context *ev, TALLOC_CTX *mem_ctx, int fd, uint16_t flags, tevent_fd_handler_t handler, void *private_data, const char *handler_name, const char *location); void (*set_fd_close_fn)(struct tevent_fd *fde, tevent_fd_close_fn_t close_fn); uint16_t (*get_fd_flags)(struct tevent_fd *fde); void (*set_fd_flags)(struct tevent_fd *fde, uint16_t flags); /* timed_event functions */ struct tevent_timer *(*add_timer)(struct tevent_context *ev, TALLOC_CTX *mem_ctx, struct timeval next_event, tevent_timer_handler_t handler, void *private_data, const char *handler_name, const char *location); /* immediate event functions */ void (*schedule_immediate)(struct tevent_immediate *im, struct tevent_context *ev, tevent_immediate_handler_t handler, void *private_data, const char *handler_name, const char *location); /* signal functions */ struct tevent_signal *(*add_signal)(struct tevent_context *ev, TALLOC_CTX *mem_ctx, int signum, int sa_flags, tevent_signal_handler_t handler, void *private_data, const char *handler_name, const char *location); /* loop functions */ int (*loop_once)(struct tevent_context *ev, const char *location); int (*loop_wait)(struct tevent_context *ev, const char *location); }; bool tevent_register_backend(const char *name, const struct tevent_ops *ops); /* @} */ /** * @defgroup tevent_compat The tevent compatibility functions * @ingroup tevent * * The following definitions are usueful only for compatibility with the * implementation originally developed within the samba4 code and will be * soon removed. Please NEVER use in new code. * * @todo Ignore it? * * @{ */ #ifdef TEVENT_COMPAT_DEFINES #define event_context tevent_context #define event_ops tevent_ops #define fd_event tevent_fd #define timed_event tevent_timer #define signal_event tevent_signal #define event_fd_handler_t tevent_fd_handler_t #define event_timed_handler_t tevent_timer_handler_t #define event_signal_handler_t tevent_signal_handler_t #define event_context_init(mem_ctx) \ tevent_context_init(mem_ctx) #define event_context_init_byname(mem_ctx, name) \ tevent_context_init_byname(mem_ctx, name) #define event_backend_list(mem_ctx) \ tevent_backend_list(mem_ctx) #define event_set_default_backend(backend) \ tevent_set_default_backend(backend) #define event_add_fd(ev, mem_ctx, fd, flags, handler, private_data) \ tevent_add_fd(ev, mem_ctx, fd, flags, handler, private_data) #define event_add_timed(ev, mem_ctx, next_event, handler, private_data) \ tevent_add_timer(ev, mem_ctx, next_event, handler, private_data) #define event_add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data) \ tevent_add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data) #define event_loop_once(ev) \ tevent_loop_once(ev) #define event_loop_wait(ev) \ tevent_loop_wait(ev) #define event_get_fd_flags(fde) \ tevent_fd_get_flags(fde) #define event_set_fd_flags(fde, flags) \ tevent_fd_set_flags(fde, flags) #define EVENT_FD_READ TEVENT_FD_READ #define EVENT_FD_WRITE TEVENT_FD_WRITE #define EVENT_FD_WRITEABLE(fde) \ TEVENT_FD_WRITEABLE(fde) #define EVENT_FD_READABLE(fde) \ TEVENT_FD_READABLE(fde) #define EVENT_FD_NOT_WRITEABLE(fde) \ TEVENT_FD_NOT_WRITEABLE(fde) #define EVENT_FD_NOT_READABLE(fde) \ TEVENT_FD_NOT_READABLE(fde) #define ev_debug_level tevent_debug_level #define EV_DEBUG_FATAL TEVENT_DEBUG_FATAL #define EV_DEBUG_ERROR TEVENT_DEBUG_ERROR #define EV_DEBUG_WARNING TEVENT_DEBUG_WARNING #define EV_DEBUG_TRACE TEVENT_DEBUG_TRACE #define ev_set_debug(ev, debug, context) \ tevent_set_debug(ev, debug, context) #define ev_set_debug_stderr(_ev) tevent_set_debug_stderr(ev) #endif /* TEVENT_COMPAT_DEFINES */ /* @} */ #endif /* __TEVENT_H__ */