diff options
Diffstat (limited to 'tevent.h')
| -rw-r--r-- | tevent.h | 2960 |
1 files changed, 2960 insertions, 0 deletions
diff --git a/tevent.h b/tevent.h new file mode 100644 index 0000000..3039185 --- /dev/null +++ b/tevent.h @@ -0,0 +1,2960 @@ +/* + 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 <http://www.gnu.org/licenses/>. +*/ + +#ifndef __TEVENT_H__ +#define __TEVENT_H__ + +#include <stdint.h> +#include <talloc.h> +#include <sys/time.h> +#include <sys/types.h> +#include <stdbool.h> + +/* for old gcc releases that don't have the feature test macro __has_attribute */ +#ifndef __has_attribute +#define __has_attribute(x) 0 +#endif + + +struct tevent_context; +struct tevent_ops; +struct tevent_fd; +struct tevent_timer; +struct tevent_immediate; +struct tevent_signal; +struct tevent_thread_proxy; +struct tevent_threaded_context; + +/** + * @defgroup tevent The tevent API + * + * The tevent low-level API + * + * This API provides the public interface to manage events in the tevent + * mainloop. Functions are provided for managing low-level events such + * as timer events, fd events and signal handling. + * + * @{ + */ + +/* event handler types */ +/** + * Called when a file descriptor monitored by tevent has + * data to be read or written on it. + */ +typedef void (*tevent_fd_handler_t)(struct tevent_context *ev, + struct tevent_fd *fde, + uint16_t flags, + void *private_data); + +/** + * Called when tevent is ceasing the monitoring of a file descriptor. + */ +typedef void (*tevent_fd_close_fn_t)(struct tevent_context *ev, + struct tevent_fd *fde, + int fd, + void *private_data); + +/** + * Called when a tevent timer has fired. + */ +typedef void (*tevent_timer_handler_t)(struct tevent_context *ev, + struct tevent_timer *te, + struct timeval current_time, + void *private_data); + +/** + * Called when a tevent immediate event is invoked. + */ +typedef void (*tevent_immediate_handler_t)(struct tevent_context *ctx, + struct tevent_immediate *im, + void *private_data); + +/** + * Called after tevent detects the specified signal. + */ +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 select a specific backend. + * + * 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 of the backend to use. + * + * @return An allocated tevent context, NULL on error. + */ +struct tevent_context *tevent_context_init_byname(TALLOC_CTX *mem_ctx, const char *name); + +/** + * @brief Create a custom event context + * + * @param[in] mem_ctx The memory context to use. + * @param[in] ops The function pointer table of the backend. + * @param[in] additional_data The additional/private data to this instance + * + * @return An allocated tevent context, NULL on error. + * + */ +struct tevent_context *tevent_context_init_ops(TALLOC_CTX *mem_ctx, + const struct tevent_ops *ops, + void *additional_data); + +/** + * @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 backend. + * + * @param[in] backend The name of the backend to set. + */ +void tevent_set_default_backend(const char *backend); + +#ifdef DOXYGEN +/** + * @brief Add a file descriptor based event. + * + * @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 #TEVENT_FD_READ or #TEVENT_FD_WRITE + * + * @param[in] handler The callback handler for the event. + * + * @param[in] private_data The private data passed to the callback handler. + * + * @return The file descriptor based event, NULL on error. + * + * @note To cancel the monitoring of a file descriptor, call talloc_free() + * on the object returned by this function. + * + * @note The caller should avoid closing the file descriptor before + * calling talloc_free()! Otherwise the behaviour is undefined which + * might result in crashes. See https://bugzilla.samba.org/show_bug.cgi?id=11141 + * for an example. + */ +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); +#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 + +/** + * @brief Associate a custom tag with the event. + * + * This tag can be then retrieved with tevent_fd_get_tag() + * + * @param[in] fde The file descriptor event. + * + * @param[in] tag Custom tag. + */ +void tevent_fd_set_tag(struct tevent_fd *fde, uint64_t tag); + +/** + * @brief Get custom event tag. + */ +uint64_t tevent_fd_get_tag(const struct tevent_fd *fde); + +#ifdef DOXYGEN +/** + * @brief Add a timed event + * + * @param[in] ev The event context to work on. + * + * @param[in] mem_ctx The talloc memory context to use. + * + * @param[in] next_event Timeval specifying the absolute time to fire this + * event. This is not an offset. + * + * @param[in] handler The callback handler for the event. + * + * @param[in] private_data The private data passed to the callback handler. + * + * @return The newly-created timer event, or NULL on error. + * + * @note To cancel a timer event before it fires, call talloc_free() on the + * event returned from this function. This event is automatically + * talloc_free()-ed after its event handler files, if it hasn't been freed yet. + * + * @note Unlike some mainloops, tevent timers are one-time events. To set up + * a recurring event, it is necessary to call tevent_add_timer() again during + * the handler processing. + * + * @note Due to the internal mainloop processing, a timer set to run + * immediately will do so after any other pending timers fire, but before + * any further file descriptor or signal handling events fire. Callers should + * not rely on this behavior! + */ +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); +#else +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__) +#endif + +/** + * @brief Set the time a tevent_timer fires + * + * @param[in] te The timer event to reset + * + * @param[in] next_event Timeval specifying the absolute time to fire this + * event. This is not an offset. + */ +void tevent_update_timer(struct tevent_timer *te, struct timeval next_event); + +/** + * @brief Associate a custom tag with the event. + * + * This tag can be then retrieved with tevent_timer_get_tag() + * + * @param[in] te The timer event. + * + * @param[in] tag Custom tag. + */ +void tevent_timer_set_tag(struct tevent_timer *te, uint64_t tag); + +/** + * @brief Get custom event tag. + */ +uint64_t tevent_timer_get_tag(const struct tevent_timer *te); + +#ifdef DOXYGEN +/** + * Initialize an immediate event object + * + * This object can be used to trigger an event to occur immediately after + * returning from the current event (before any other event occurs) + * + * @param[in] mem_ctx The talloc memory context to use as the parent + * + * @return An empty tevent_immediate object. Use tevent_schedule_immediate + * to populate and use it. + * + * @note Available as of tevent 0.9.8 + */ +struct tevent_immediate *tevent_create_immediate(TALLOC_CTX *mem_ctx); +#else +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__) +#endif + +#ifdef DOXYGEN + +/** + * Schedule an event for immediate execution. This event will occur + * immediately after returning from the current event (before any other + * event occurs) + * + * @param[in] im The tevent_immediate object to populate and use + * @param[in] ctx The tevent_context to run this event + * @param[in] handler The event handler to run when this event fires + * @param[in] private_data Data to pass to the event handler + */ +void tevent_schedule_immediate(struct tevent_immediate *im, + struct tevent_context *ctx, + tevent_immediate_handler_t handler, + void *private_data); +#else +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__); +#endif + +/** + * @brief Associate a custom tag with the event. + * + * This tag can be then retrieved with tevent_immediate_get_tag() + * + * @param[in] im The immediate event. + * + * @param[in] tag Custom tag. + */ +void tevent_immediate_set_tag(struct tevent_immediate *im, uint64_t tag); + +/** + * @brief Get custom event tag. + */ +uint64_t tevent_immediate_get_tag(const struct tevent_immediate *fde); + +#ifdef DOXYGEN +/** + * @brief Add a tevent signal handler + * + * tevent_add_signal() creates a new event for handling a signal the next + * time through the mainloop. It implements a very simple traditional signal + * handler whose only purpose is to add the handler event into the mainloop. + * + * @param[in] ev The event context to work on. + * + * @param[in] mem_ctx The talloc memory context to use. + * + * @param[in] signum The signal to trap + * + * @param[in] handler The callback handler for the signal. + * + * @param[in] sa_flags sigaction flags for this signal handler. + * + * @param[in] private_data The private data passed to the callback handler. + * + * @return The newly-created signal handler event, or NULL on error. + * + * @note To cancel a signal handler, call talloc_free() on the event returned + * from this function. + * + * @see tevent_num_signals, tevent_sa_info_queue_count + */ +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); +#else +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__) +#endif + +/** + * @brief Associate a custom tag with the event. + * + * This tag can be then retrieved with tevent_signal_get_tag() + * + * @param[in] fde The signal event. + * + * @param[in] tag Custom tag. + */ +void tevent_signal_set_tag(struct tevent_signal *se, uint64_t tag); + +/** + * @brief Get custom event tag. + */ +uint64_t tevent_signal_get_tag(const struct tevent_signal *se); + +/** + * @brief the number of supported signals + * + * This returns value of the configure time TEVENT_NUM_SIGNALS constant. + * + * The 'signum' argument of tevent_add_signal() must be less than + * TEVENT_NUM_SIGNALS. + * + * @see tevent_add_signal + */ +size_t tevent_num_signals(void); + +/** + * @brief the number of pending realtime signals + * + * This returns value of TEVENT_SA_INFO_QUEUE_COUNT. + * + * The tevent internals remember the last TEVENT_SA_INFO_QUEUE_COUNT + * siginfo_t structures for SA_SIGINFO signals. If the system generates + * more some signals get lost. + * + * @see tevent_add_signal + */ +size_t tevent_sa_info_queue_count(void); + +#ifdef DOXYGEN +/** + * @brief Pass a single time through the mainloop + * + * This will process any appropriate signal, immediate, fd and timer events + * + * @param[in] ev The event context to process + * + * @return Zero on success, nonzero if an internal error occurred + */ +int tevent_loop_once(struct tevent_context *ev); +#else +int _tevent_loop_once(struct tevent_context *ev, const char *location); +#define tevent_loop_once(ev) \ + _tevent_loop_once(ev, __location__) +#endif + +#ifdef DOXYGEN +/** + * @brief Run the mainloop + * + * The mainloop will run until there are no events remaining to be processed + * + * @param[in] ev The event context to process + * + * @return Zero if all events have been processed. Nonzero if an internal + * error occurred. + */ +int tevent_loop_wait(struct tevent_context *ev); +#else +int _tevent_loop_wait(struct tevent_context *ev, const char *location); +#define tevent_loop_wait(ev) \ + _tevent_loop_wait(ev, __location__) +#endif + + +/** + * Assign a function to run when a tevent_fd is freed + * + * This function is a destructor for the tevent_fd. It does not automatically + * close the file descriptor. If this is the desired behavior, then it must be + * performed by the close_fn. + * + * @param[in] fde File descriptor event on which to set the destructor + * @param[in] close_fn Destructor to execute when fde is freed + * + * @note That the close_fn() on tevent_fd is *NOT* wrapped on contexts + * created by tevent_context_wrapper_create()! + * + * @see tevent_fd_set_close_fn + * @see tevent_context_wrapper_create + */ +void tevent_fd_set_close_fn(struct tevent_fd *fde, + tevent_fd_close_fn_t close_fn); + +/** + * Automatically close the file descriptor when the tevent_fd is freed + * + * This function calls close(fd) internally. + * + * @param[in] fde File descriptor event to auto-close + * + * @see tevent_fd_set_close_fn + */ +void tevent_fd_set_auto_close(struct tevent_fd *fde); + +/** + * Return the flags set on this file descriptor event + * + * @param[in] fde File descriptor event to query + * + * @return The flags set on the event. See #TEVENT_FD_READ and + * #TEVENT_FD_WRITE + */ +uint16_t tevent_fd_get_flags(struct tevent_fd *fde); + +/** + * Set flags on a file descriptor event + * + * @param[in] fde File descriptor event to set + * @param[in] flags Flags to set on the event. See #TEVENT_FD_READ and + * #TEVENT_FD_WRITE + */ +void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags); + +/** + * Query whether tevent supports signal handling + * + * @param[in] ev An initialized tevent context + * + * @return True if this platform and tevent context support signal handling + */ +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 */ + +/** + * Monitor a file descriptor for data to be read + */ +#define TEVENT_FD_READ 1 +/** + * Monitor a file descriptor for writeability + */ +#define TEVENT_FD_WRITE 2 + +/** + * Convenience function for declaring a tevent_fd writable + */ +#define TEVENT_FD_WRITEABLE(fde) \ + tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) | TEVENT_FD_WRITE) + +/** + * Convenience function for declaring a tevent_fd readable + */ +#define TEVENT_FD_READABLE(fde) \ + tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) | TEVENT_FD_READ) + +/** + * Convenience function for declaring a tevent_fd non-writable + */ +#define TEVENT_FD_NOT_WRITEABLE(fde) \ + tevent_fd_set_flags(fde, tevent_fd_get_flags(fde) & ~TEVENT_FD_WRITE) + +/** + * Convenience function for declaring a tevent_fd non-readable + */ +#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 +}; + +/** + * @brief The tevent debug callbac. + * + * @param[in] context The memory context to use. + * + * @param[in] level The debug level. + * + * @param[in] fmt The format string. + * + * @param[in] ap The arguments for the format string. + */ +typedef void (*tevent_debug_fn)(void *context, + enum tevent_debug_level level, + const char *fmt, + va_list ap) PRINTF_ATTRIBUTE(3,0); + +/** + * Set destination for tevent debug messages + * + * @param[in] ev Event context to debug + * @param[in] debug Function to handle output printing + * @param[in] context The context to pass to the debug function. + * + * @return Always returns 0 as of version 0.9.8 + * + * @note Default is to emit no debug messages + */ +int tevent_set_debug(struct tevent_context *ev, + tevent_debug_fn debug, + void *context); + +/** + * Designate stderr for debug message output + * + * @param[in] ev Event context to debug + * + * @note This function will only output TEVENT_DEBUG_FATAL, TEVENT_DEBUG_ERROR + * and TEVENT_DEBUG_WARNING messages. For TEVENT_DEBUG_TRACE, please define a + * function for tevent_set_debug() + */ +int tevent_set_debug_stderr(struct tevent_context *ev); + +enum tevent_trace_point { + /** + * Corresponds to a trace point just before waiting + */ + TEVENT_TRACE_BEFORE_WAIT, + /** + * Corresponds to a trace point just after waiting + */ + TEVENT_TRACE_AFTER_WAIT, +#define TEVENT_HAS_LOOP_ONCE_TRACE_POINTS 1 + /** + * Corresponds to a trace point just before calling + * the loop_once() backend function. + */ + TEVENT_TRACE_BEFORE_LOOP_ONCE, + /** + * Corresponds to a trace point right after the + * loop_once() backend function has returned. + */ + TEVENT_TRACE_AFTER_LOOP_ONCE, +}; + +typedef void (*tevent_trace_callback_t)(enum tevent_trace_point, + void *private_data); + +/** + * Register a callback to be called at certain trace points + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_callback(struct tevent_context *ev, + tevent_trace_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_callback(struct tevent_context *ev, + tevent_trace_callback_t *cb, + void *private_data); + +enum tevent_event_trace_point { + /** + * Corresponds to a trace point just before the event is added. + */ + TEVENT_EVENT_TRACE_ATTACH, + + /** + * Corresponds to a trace point just before the event is removed. + */ + TEVENT_EVENT_TRACE_DETACH, + + /** + * Corresponds to a trace point just before the event handler is called. + */ + TEVENT_EVENT_TRACE_BEFORE_HANDLER, +}; + +typedef void (*tevent_trace_fd_callback_t)(struct tevent_fd *fde, + enum tevent_event_trace_point, + void *private_data); + +typedef void (*tevent_trace_signal_callback_t)(struct tevent_signal *se, + enum tevent_event_trace_point, + void *private_data); + +typedef void (*tevent_trace_timer_callback_t)(struct tevent_timer *te, + enum tevent_event_trace_point, + void *private_data); + +typedef void (*tevent_trace_immediate_callback_t)(struct tevent_immediate *im, + enum tevent_event_trace_point, + void *private_data); + +/** + * Register a callback to be called at certain trace points of fd event. + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_event_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_fd_callback(struct tevent_context *ev, + tevent_trace_fd_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback of file descriptor event. + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] p_private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_fd_callback(struct tevent_context *ev, + tevent_trace_fd_callback_t *cb, + void *p_private_data); + +/** + * Register a callback to be called at certain trace points of signal event. + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_event_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_signal_callback(struct tevent_context *ev, + tevent_trace_signal_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback of signal event. + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] p_private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_signal_callback(struct tevent_context *ev, + tevent_trace_signal_callback_t *cb, + void *p_private_data); + +/** + * Register a callback to be called at certain trace points of timer event. + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_event_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_timer_callback(struct tevent_context *ev, + tevent_trace_timer_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback of timer event. + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] p_private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_timer_callback(struct tevent_context *ev, + tevent_trace_timer_callback_t *cb, + void *p_private_data); + +/** + * Register a callback to be called at certain trace points of immediate event. + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_event_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_immediate_callback(struct tevent_context *ev, + tevent_trace_immediate_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback of immediate event. + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] p_private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_immediate_callback(struct tevent_context *ev, + tevent_trace_immediate_callback_t *cb, + void *p_private_data); + +/** + * @} + */ + +/** + * @defgroup tevent_request The tevent request functions. + * @ingroup tevent + * + * A tevent_req represents an asynchronous computation. + * + * The tevent_req group of API calls is the recommended way of + * programming async computations within tevent. In particular the + * file descriptor (tevent_add_fd) and timer (tevent_add_timed) events + * are considered too low-level to be used in larger computations. To + * read and write from and to sockets, Samba provides two calls on top + * of tevent_add_fd: tstream_read_packet_send/recv and tstream_writev_send/recv. + * These requests are much easier to compose than the low-level event + * handlers called from tevent_add_fd. + * + * A lot of the simplicity tevent_req has brought to the notoriously + * hairy async programming came via a set of conventions that every + * async computation programmed should follow. One central piece of + * these conventions is the naming of routines and variables. + * + * Every async computation needs a name (sensibly called "computation" + * down from here). From this name quite a few naming conventions are + * derived. + * + * Every computation that requires local state needs a + * @code + * struct computation_state { + * int local_var; + * }; + * @endcode + * Even if no local variables are required, such a state struct should + * be created containing a dummy variable. Quite a few helper + * functions and macros (for example tevent_req_create()) assume such + * a state struct. + * + * An async computation is started by a computation_send + * function. When it is finished, its result can be received by a + * computation_recv function. For an example how to set up an async + * computation, see the code example in the documentation for + * tevent_req_create() and tevent_req_post(). The prototypes for _send + * and _recv functions should follow some conventions: + * + * @code + * struct tevent_req *computation_send(TALLOC_CTX *mem_ctx, + * struct tevent_context *ev, + * ... further args); + * int computation_recv(struct tevent_req *req, ... further output args); + * @endcode + * + * The "int" result of computation_recv() depends on the result the + * sync version of the function would have, "int" is just an example + * here. + * + * Another important piece of the conventions is that the program flow + * is interrupted as little as possible. Because a blocking + * sub-computation requires that the flow needs to continue in a + * separate function that is the logical sequel of some computation, + * it should lexically follow sending off the blocking + * sub-computation. Setting the callback function via + * tevent_req_set_callback() requires referencing a function lexically + * below the call to tevent_req_set_callback(), forward declarations + * are required. A lot of the async computations thus begin with a + * sequence of declarations such as + * + * @code + * static void computation_step1_done(struct tevent_req *subreq); + * static void computation_step2_done(struct tevent_req *subreq); + * static void computation_step3_done(struct tevent_req *subreq); + * @endcode + * + * It really helps readability a lot to do these forward declarations, + * because the lexically sequential program flow makes the async + * computations almost as clear to read as a normal, sync program + * flow. + * + * It is up to the user of the async computation to talloc_free it + * after it has finished. If an async computation should be aborted, + * the tevent_req structure can be talloc_free'ed. After it has + * finished, it should talloc_free'ed by the API user. + * + * tevent_req variable naming conventions: + * + * The name of the variable pointing to the tevent_req structure + * returned by a _send() function SHOULD be named differently between + * implementation and caller. + * + * From the point of view of the implementation (of the _send() and + * _recv() functions) the variable returned by tevent_req_create() is + * always called @em req. + * + * While the caller of the _send() function should use @em subreq to + * hold the result. + * + * @see tevent_req_create() + * @see tevent_req_fn() + * + * @{ + */ + +/** + * An async request moves from TEVENT_REQ_INIT to + * TEVENT_REQ_IN_PROGRESS. All other states are valid after a request + * has finished. + */ +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 successfully + */ + TEVENT_REQ_DONE, + /** + * A user error has occurred. The user error has been + * indicated by tevent_req_error(), it can be retrieved via + * tevent_req_is_error(). + */ + TEVENT_REQ_USER_ERROR, + /** + * Request timed out after the timeout set by tevent_req_set_endtime. + */ + TEVENT_REQ_TIMED_OUT, + /** + * An internal allocation has failed, or tevent_req_nomem has + * been given a NULL pointer as the first argument. + */ + TEVENT_REQ_NO_MEMORY, + /** + * The request has been received by the caller. No further + * action is valid. + */ + TEVENT_REQ_RECEIVED +}; + +/** + * @brief An async request + */ +struct tevent_req; + +/** + * @brief A tevent request callback function. + * + * @param[in] subreq The tevent async request which executed this callback. + */ +typedef void (*tevent_req_fn)(struct tevent_req *subreq); + +/** + * @brief Set an async request callback. + * + * See the documentation of tevent_req_post() for an example how this + * is supposed to be used. + * + * @param[in] req The async request to set the callback. + * + * @param[in] fn The callback function to set. + * + * @param[in] pvt A pointer to private data to pass to the async request + * callback. + */ +void tevent_req_set_callback(struct tevent_req *req, tevent_req_fn fn, void *pvt); + +#ifdef DOXYGEN +/** + * @brief Get the private data cast to the given type for a callback from + * a tevent request structure. + * + * @code + * static void computation_done(struct tevent_req *subreq) { + * struct tevent_req *req = tevent_req_callback_data(subreq, struct tevent_req); + * struct computation_state *state = tevent_req_data(req, struct computation_state); + * .... more things, eventually maybe call tevent_req_done(req); + * } + * @endcode + * + * @param[in] req The structure to get the callback data from. + * + * @param[in] type The type of the private callback data to get. + * + * @return The type casted private data set NULL if not set. + */ +void *tevent_req_callback_data(struct tevent_req *req, #type); +#else +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) +#endif + +#ifdef DOXYGEN +/** + * @brief Get the private data for a callback from a tevent request structure. + * + * @param[in] req The structure to get the callback data from. + * + * @return The private data or NULL if not set. + */ +void *tevent_req_callback_data_void(struct tevent_req *req); +#else +#define tevent_req_callback_data_void(_req) \ + _tevent_req_callback_data(_req) +#endif + +#ifdef DOXYGEN +/** + * @brief Get the private data from a tevent request structure. + * + * When the tevent_req has been created by tevent_req_create, the + * result of tevent_req_data() is the state variable created by + * tevent_req_create() as a child of the req. + * + * @param[in] req The structure to get the private data from. + * + * @param[in] type The type of the private data + * + * @return The private data or NULL if not set. + */ +void *tevent_req_data(struct tevent_req *req, #type); +#else +void *_tevent_req_data(struct tevent_req *req); +#define tevent_req_data(_req, _type) \ + talloc_get_type_abort(_tevent_req_data(_req), _type) +#endif + +/** + * @brief The print function which can be set for a tevent async request. + * + * @param[in] req The tevent async request. + * + * @param[in] ctx A talloc memory context which can be uses to allocate + * memory. + * + * @return An allocated string buffer to print. + * + * Example: + * @code + * static char *my_print(struct tevent_req *req, TALLOC_CTX *mem_ctx) + * { + * struct my_data *data = tevent_req_data(req, struct my_data); + * char *result; + * + * result = tevent_req_default_print(mem_ctx, req); + * if (result == NULL) { + * return NULL; + * } + * + * return talloc_asprintf_append_buffer(result, "foo=%d, bar=%d", + * data->foo, data->bar); + * } + * @endcode + */ +typedef char *(*tevent_req_print_fn)(struct tevent_req *req, TALLOC_CTX *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); + +/** + * @brief A typedef for a cancel function for a tevent request. + * + * @param[in] req The tevent request calling this function. + * + * @return True if the request could be canceled, false if not. + */ +typedef bool (*tevent_req_cancel_fn)(struct tevent_req *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 if the request is + * cancelable, otherwise 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 + +/** + * @brief A typedef for a cleanup function for a tevent request. + * + * @param[in] req The tevent request calling this function. + * + * @param[in] req_state The current tevent_req_state. + * + */ +typedef void (*tevent_req_cleanup_fn)(struct tevent_req *req, + enum tevent_req_state req_state); + +/** + * @brief This function sets a cleanup function for the given tevent request. + * + * This function can be used to setup a cleanup function for the given request. + * This will be triggered when the tevent_req_done() or tevent_req_error() + * function was called, before notifying the callers callback function, + * and also before scheduling the deferred trigger. + * + * This might be useful if more than one tevent_req belong together + * and need to finish both requests at the same time. + * + * The cleanup function is able to call tevent_req_done() or tevent_req_error() + * recursively, the cleanup function is only triggered the first time. + * + * The cleanup function is also called by tevent_req_received() + * (possibly triggered from tevent_req_destructor()) before destroying + * the private data of the tevent_req. + * + * @param[in] req The request to use. + * + * @param[in] fn A pointer to the cancel function. + */ +void tevent_req_set_cleanup_fn(struct tevent_req *req, tevent_req_cleanup_fn fn); + +#ifdef DOXYGEN +/** + * @brief Create an async tevent request. + * + * The new async request will be initialized in state TEVENT_REQ_IN_PROGRESS. + * + * @code + * struct tevent_req *req; + * struct computation_state *state; + * req = tevent_req_create(mem_ctx, &state, struct computation_state); + * @endcode + * + * Tevent_req_create() allocates and zeros the state variable as a talloc + * child of its result. The state variable should be used as the talloc + * parent for all temporary variables that are allocated during the async + * computation. This way, when the user of the async computation frees + * the request, the state as a talloc child will be free'd along with + * all the temporary variables hanging off the state. + * + * @param[in] mem_ctx The memory context for the result. + * @param[in] pstate Pointer to the private request state. + * @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, #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 + +/** + * @brief Set a timeout for an async request. On failure, "req" is already + * set to state TEVENT_REQ_NO_MEMORY. + * + * @param[in] req The request to set the timeout for. + * + * @param[in] ev The event context to use for the timer. + * + * @param[in] endtime The endtime of the request. + * + * @return True if succeeded, false if not. + */ +bool tevent_req_set_endtime(struct tevent_req *req, + struct tevent_context *ev, + struct timeval endtime); + +/** + * @brief Reset the timer set by tevent_req_set_endtime. + * + * @param[in] req The request to reset the timeout for + */ +void tevent_req_reset_endtime(struct tevent_req *req); + +#ifdef DOXYGEN +/** + * @brief Call the notify callback of the given tevent request manually. + * + * @param[in] req The tevent request to call the notify function from. + * + * @see tevent_req_set_callback() + */ +void tevent_req_notify_callback(struct tevent_req *req); +#else +void _tevent_req_notify_callback(struct tevent_req *req, const char *location); +#define tevent_req_notify_callback(req) \ + _tevent_req_notify_callback(req, __location__) +#endif + +#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 + +#ifdef DOXYGEN +/** + * @brief Indicate out of memory to a request + * + * @param[in] req The request being processed. + */ +void tevent_req_oom(struct tevent_req *req); +#else +void _tevent_req_oom(struct tevent_req *req, + const char *location); +#define tevent_req_oom(req) \ + _tevent_req_oom(req, __location__) +#endif + +/** + * @brief Finish a request before the caller had a chance 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 not 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 event. This way the caller can use the same calling + * conventions, independent of whether the request was actually deferred. + * + * @code + * struct tevent_req *computation_send(TALLOC_CTX *mem_ctx, + * struct tevent_context *ev) + * { + * struct tevent_req *req, *subreq; + * struct computation_state *state; + * req = tevent_req_create(mem_ctx, &state, struct computation_state); + * if (req == NULL) { + * return NULL; + * } + * subreq = subcomputation_send(state, ev); + * if (tevent_req_nomem(subreq, req)) { + * return tevent_req_post(req, ev); + * } + * tevent_req_set_callback(subreq, computation_done, req); + * return req; + * } + * @endcode + * + * @param[in] req The finished request. + * + * @param[in] ev The tevent_context for the immediate event. + * + * @return The given request will be returned. + */ +struct tevent_req *tevent_req_post(struct tevent_req *req, + struct tevent_context *ev); + +/** + * @brief Finish multiple requests within one function + * + * Normally tevent_req_notify_callback() and all wrappers + * (e.g. tevent_req_done() and tevent_req_error()) + * need to be the last thing an event handler should call. + * This is because the callback is likely to destroy the + * context of the current function. + * + * If a function wants to notify more than one caller, + * it is dangerous if it just triggers multiple callbacks + * in a row. With tevent_req_defer_callback() it is possible + * to set an event context that will be used to defer the callback + * via an immediate event (similar to tevent_req_post()). + * + * @code + * struct complete_state { + * struct tevent_context *ev; + * + * struct tevent_req **reqs; + * }; + * + * void complete(struct complete_state *state) + * { + * size_t i, c = talloc_array_length(state->reqs); + * + * for (i=0; i < c; i++) { + * tevent_req_defer_callback(state->reqs[i], state->ev); + * tevent_req_done(state->reqs[i]); + * } + * } + * @endcode + * + * @param[in] req The finished request. + * + * @param[in] ev The tevent_context for the immediate event. + * + * @return The given request will be returned. + */ +void tevent_req_defer_callback(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. + * + * @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); + +/** + * @brief Get the tevent request state and the actual error set by + * tevent_req_error. + * + * @code + * int computation_recv(struct tevent_req *req, uint64_t *perr) + * { + * enum tevent_req_state state; + * uint64_t err; + * if (tevent_req_is_error(req, &state, &err)) { + * *perr = err; + * return -1; + * } + * return 0; + * } + * @endcode + * + * @param[in] req The tevent request to get the error from. + * + * @param[out] state A pointer to store the tevent request error state. + * + * @param[out] error A pointer to store the error set by tevent_req_error(). + * + * @return True if the function could set error and state, false + * otherwise. + * + * @see tevent_req_error() + */ +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); + +/** + * @brief Mark a tevent_req for profiling + * + * This will turn on profiling for this tevent_req an all subreqs that + * are directly started as helper requests off this + * tevent_req. subreqs are chained by walking up the talloc_parent + * hierarchy at a subreq's tevent_req_create. This means to get the + * profiling chain right the subreq that needs to be profiled as part + * of this tevent_req's profile must be a talloc child of the requests + * state variable. + * + * @param[in] req The request to do tracing for + * + * @return False if the profile could not be activated + */ +bool tevent_req_set_profile(struct tevent_req *req); + +struct tevent_req_profile; + +/** + * @brief Get the a request's profile for inspection + * + * @param[in] req The request to get the profile from + * + * @return The request's profile + */ +const struct tevent_req_profile *tevent_req_get_profile( + struct tevent_req *req); + +/** + * @brief Move the profile out of a request + * + * This function detaches the request's profile from the request, so + * that the profile can outlive the request in a _recv function. + * + * @param[in] req The request to move the profile out of + * @param[in] mem_ctx The new talloc context for the profile + * + * @return The moved profile + */ + +struct tevent_req_profile *tevent_req_move_profile(struct tevent_req *req, + TALLOC_CTX *mem_ctx); + +/** + * @brief Get a profile description + * + * @param[in] profile The profile to be queried + * @param[in] req_name The name of the request (state's name) + * + * "req_name" after this call is still in talloc-posession of "profile" + */ +void tevent_req_profile_get_name(const struct tevent_req_profile *profile, + const char **req_name); + +/** + * @brief Get a profile's start event data + * + * @param[in] profile The profile to be queried + * @param[in] start_location The location where this event started + * @param[in] start_time The time this event started + * + * "start_location" after this call is still in talloc-posession of "profile" + */ +void tevent_req_profile_get_start(const struct tevent_req_profile *profile, + const char **start_location, + struct timeval *start_time); + +/** + * @brief Get a profile's stop event data + * + * @param[in] profile The profile to be queried + * @param[in] stop_location The location where this event stopped + * @param[in] stop_time The time this event stopped + * + * "stop_location" after this call is still in talloc-posession of "profile" + */ +void tevent_req_profile_get_stop(const struct tevent_req_profile *profile, + const char **stop_location, + struct timeval *stop_time); + +/** + * @brief Get a profile's result data + * + * @param[in] pid The process where this profile was taken + * @param[in] state The status the profile's tevent_req finished with + * @param[in] user_error The user error of the profile's tevent_req + */ +void tevent_req_profile_get_status(const struct tevent_req_profile *profile, + pid_t *pid, + enum tevent_req_state *state, + uint64_t *user_error); + +/** + * @brief Retrieve the first subreq's profile from a profile + * + * @param[in] profile The profile to query + * + * @return The first tevent subreq's profile + */ +const struct tevent_req_profile *tevent_req_profile_get_subprofiles( + const struct tevent_req_profile *profile); + +/** + * @brief Walk the chain of subreqs + * + * @param[in] profile The subreq's profile to walk + * + * @return The next subprofile in the list + */ +const struct tevent_req_profile *tevent_req_profile_next( + const struct tevent_req_profile *profile); + +/** + * @brief Create a fresh tevent_req_profile + * + * @param[in] mem_ctx The talloc context to hang the fresh struct off + * + * @return The fresh struct + */ +struct tevent_req_profile *tevent_req_profile_create(TALLOC_CTX *mem_ctx); + +/** + * @brief Set a profile's name + * + * @param[in] profile The profile to set the name for + * @param[in] name The new name for the profile + * + * @return True if the internal talloc_strdup succeeded + */ +bool tevent_req_profile_set_name(struct tevent_req_profile *profile, + const char *name); + +/** + * @brief Set a profile's start event + * + * @param[in] profile The profile to set the start data for + * @param[in] start_location The new start location + * @param[in] start_time The new start time + * + * @return True if the internal talloc_strdup succeeded + */ +bool tevent_req_profile_set_start(struct tevent_req_profile *profile, + const char *start_location, + struct timeval start_time); + +/** + * @brief Set a profile's stop event + * + * @param[in] profile The profile to set the stop data for + * @param[in] stop_location The new stop location + * @param[in] stop_time The new stop time + * + * @return True if the internal talloc_strdup succeeded + */ +bool tevent_req_profile_set_stop(struct tevent_req_profile *profile, + const char *stop_location, + struct timeval stop_time); + +/** + * @brief Set a profile's exit status + * + * @param[in] profile The profile to set the exit status for + * @param[in] pid The process where this profile was taken + * @param[in] state The status the profile's tevent_req finished with + * @param[in] user_error The user error of the profile's tevent_req + */ +void tevent_req_profile_set_status(struct tevent_req_profile *profile, + pid_t pid, + enum tevent_req_state state, + uint64_t user_error); + +/** + * @brief Add a subprofile to a profile + * + * @param[in] parent_profile The profile to be modified + * @param[in] sub_profile The subreqs profile profile to be added + * + * "subreq" is talloc_move'ed into "parent_profile", so the talloc + * ownership of "sub_profile" changes + */ + +void tevent_req_profile_append_sub(struct tevent_req_profile *parent_profile, + struct tevent_req_profile **sub_profile); + +/** + * @brief Create a tevent subrequest at a given time. + * + * The idea is that always the same syntax for tevent requests. + * + * @param[in] mem_ctx The talloc memory context to use. + * + * @param[in] ev The event handle to setup the request. + * + * @param[in] wakeup_time The time to wakeup and execute the request. + * + * @return The new subrequest, NULL on error. + * + * Example: + * @code + * static void my_callback_wakeup_done(tevent_req *subreq) + * { + * struct tevent_req *req = tevent_req_callback_data(subreq, + * struct tevent_req); + * bool ok; + * + * ok = tevent_wakeup_recv(subreq); + * TALLOC_FREE(subreq); + * if (!ok) { + * tevent_req_error(req, -1); + * return; + * } + * ... + * } + * @endcode + * + * @code + * subreq = tevent_wakeup_send(mem_ctx, ev, wakeup_time); + * if (tevent_req_nomem(subreq, req)) { + * return false; + * } + * tevent_set_callback(subreq, my_callback_wakeup_done, req); + * @endcode + * + * @see tevent_wakeup_recv() + */ +struct tevent_req *tevent_wakeup_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + struct timeval wakeup_time); + +/** + * @brief Check if the wakeup has been correctly executed. + * + * This function needs to be called in the callback function set after calling + * tevent_wakeup_send(). + * + * @param[in] req The tevent request to check. + * + * @return True on success, false otherwise. + * + * @see tevent_wakeup_recv() + */ +bool tevent_wakeup_recv(struct tevent_req *req); + +/* @} */ + +/** + * @defgroup tevent_helpers The tevent helper functions + * @ingroup tevent + * + * @todo description + * + * @{ + */ + +/** + * @brief Compare two timeval values. + * + * @param[in] tv1 The first timeval value to compare. + * + * @param[in] tv2 The second timeval value to compare. + * + * @return 0 if they are equal. + * 1 if the first time is greater than the second. + * -1 if the first time is smaller than the second. + */ +int tevent_timeval_compare(const struct timeval *tv1, + const struct timeval *tv2); + +/** + * @brief Get a zero timeval value. + * + * @return A zero timeval value. + */ +struct timeval tevent_timeval_zero(void); + +/** + * @brief Get a timeval value for the current time. + * + * @return A timeval value with the current time. + */ +struct timeval tevent_timeval_current(void); + +/** + * @brief Get a timeval structure with the given values. + * + * @param[in] secs The seconds to set. + * + * @param[in] usecs The microseconds to set. + * + * @return A timeval structure with the given values. + */ +struct timeval tevent_timeval_set(uint32_t secs, uint32_t usecs); + +/** + * @brief Get the difference between two timeval values. + * + * @param[in] tv1 The first timeval. + * + * @param[in] tv2 The second timeval. + * + * @return A timeval structure with the difference between the + * first and the second value. + */ +struct timeval tevent_timeval_until(const struct timeval *tv1, + const struct timeval *tv2); + +/** + * @brief Check if a given timeval structure is zero. + * + * @param[in] tv The timeval to check if it is zero. + * + * @return True if it is zero, false otherwise. + */ +bool tevent_timeval_is_zero(const struct timeval *tv); + +/** + * @brief Add the given amount of time to a timeval structure. + * + * @param[in] tv The timeval structure to add the time. + * + * @param[in] secs The seconds to add to the timeval. + * + * @param[in] usecs The microseconds to add to the timeval. + * + * @return The timeval structure with the new time. + */ +struct timeval tevent_timeval_add(const struct timeval *tv, uint32_t secs, + uint32_t usecs); + +/** + * @brief Get a timeval in the future with a specified offset from now. + * + * @param[in] secs The seconds of the offset from now. + * + * @param[in] usecs The microseconds of the offset from now. + * + * @return A timeval with the given offset in the future. + */ +struct timeval tevent_timeval_current_ofs(uint32_t secs, uint32_t usecs); + +/** + * + * @brief A cached version of getpid() + * + * We use getpid() in a lot a performance critical situations + * in order to check if caches are still valid in the current process. + * + * Calling getpid() always add the cost of an additional syscall! + * + * When tevent is build with pthread support, we already make use + * of pthread_atfork(), so it's trivial to use it maintain a cache for getpid(). + * + * @return The pid of the current process. + */ +pid_t tevent_cached_getpid(void); + +/* @} */ + + +/** + * @defgroup tevent_thread_call_depth The tevent call depth tracking functions + * @ingroup tevent + * + * + * The call depth tracking consists of two parts. + * + * Part 1 - storing the depth inside each tevent request. + * + * Each instance of 'struct tevent_req' internally stores the value of the + * current depth. If a new subrequest is created via tevent_req_create(), the + * newly created subrequest gets the value from the parent incremented by 1. + * + * Part 2 - updating external variable with the call depth of the currently + * processed tevent request. + * + * The intended use of call depth is for the trace indentation. This is done + * by registering the address of an external size_t variable via + * tevent_thread_call_depth_activate(). And the tracing code just reads it's + * value. + * + * The updates happen during: + * + * tevent_req_create() + * - external variable is set to the value of the newly created request (i.e. + * value of the parent incremented by 1) + * + * tevent_req_notify_callback() + * - external variable is set to the value of the parent tevent request, which + * is just about to be processed + * + * tevent_queue_immediate_trigger() + * - external variable is set to the value of the request coming from the queue + * + * + * While 'Part 1' maintains the call depth value inside each teven request + * precisely, the value of the external variable depends on the call flow and + * can be changed after return from a function call, so it no longer matches + * the value of the request being processed in the current function. + * + * @code + * struct tevent_req *foo_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev) + * { + * struct tevent_req *req, *subreq; + * struct foo_state *state; + * + * // External variable has value 'X', which is the value in parent code + * // It is ok, since tracing starts often only after tevent_req_create() + * req = tevent_req_create(mem_ctx, &state, struct foo_state); + * + * // External variable has now value 'X + 1' + * D_DEBUG("foo_send(): the external variable has the expected value\n"); + * + * subreq = bar_send(state, ev, ...); + * tevent_req_set_callback(subreq, foo_done, req); + * + * // External variable has value 'X + 1 + n', where n > 0 and n is the + * // depth reached in bar_send(). + * // We want to reset it via tevent_thread_call_depth_reset_from_req(), + * // since we want the following D_DEBUG() to have the right trace + * //indentation. + * + * tevent_thread_call_depth_reset_from_req(req); + * // External variable has again value 'X + 1' taken from req. + * D_DEBUG("foo_send(): the external variable has the expected value\n"); + * return req; + * } + * + * static void foo_done(struct tevent_req *subreq) + * { + * struct tevent_req *req = + * tevent_req_callback_data(subreq, + * struct tevent_req); + * struct foo_state *state = + * tevent_req_data(req, + * struct foo_state); + * + * // external variable has value 'X + 1' + * + * D_DEBUG("foo_done(): the external variable has the expected value\n"); + * status = bar_recv(subreq, state, ...) + * tevent_req_done(req); + * } + * + * NTSTATUS foo_recv(struct tevent_req *req) + * { + * struct foo_state *state = tevent_req_data( req, struct foo_state); + * + * // external variable has value 'X' (not 'X + 1') + * // which is ok, if we consider _recv() to be an access function + * // called from the parent context + * + * D_DEBUG("foo_recv(): external variable has the value from parent\n"); + * return NT_STATUS_OK; + * } + * @endcode + * + * Interface has 3 parts: + * + * Part 1: activation/deactivation + * + * tevent_thread_call_depth_activate(), tevent_thread_call_depth_deactivate() + * + * Activating registers external size_t variable that will be maintained with + * the current call depth. + * + * Part 2: Mark the request (and its subrequests) to be tracked + * + * tevent_thread_call_depth_start(struct tevent_req *req) + * + * By default, all newly created requests have call depth set to 0. + * tevent_thread_call_depth_start() should be called shortly after + * tevent_req_create(). It sets the call depth to 1. + * Subrequest will have call depth 2 and so on. + * + * Part 3: reset the external variable using value from tevent request + * + * tevent_thread_call_depth_reset_from_req(struct tevent_req *req) + * + * If the call depth is used for trace indentation, it might be usefull to + * reset the external variable to the call depth of currently processed tevent + * request, since the ext. variable can be changed after return from a function + * call that has created subrequests. + * + * THREADING + * + * The state is thread specific, i.e. each thread can activate it and register + * its own external variable. + * + * @{ + */ + +/** + * Activate call depth tracking and register external variable that will + * be updated to the call epth of currenty processed tevent request. + * + * @param[in] ptr Address of external variable + */ +void tevent_thread_call_depth_activate(size_t *ptr); + +/** + * Deactivate call depth tracking. Can be used in the child process, + * after fork. + */ +void tevent_thread_call_depth_deactivate(void); + +/** + * This request will have call depth set to 1, its subrequest will get 2 and so + * on. All other requests will have call depth 0. + */ +void tevent_thread_call_depth_start(struct tevent_req *req); + +/** + * Set the external variable to the call depth of the request req. + * + * @param[in] req Request from which the call depth is assigned to ext. + * variable. + */ +void tevent_thread_call_depth_reset_from_req(struct tevent_req *req); + +/* @} */ + + +/** + * @defgroup tevent_queue The tevent queue functions + * @ingroup tevent + * + * A tevent_queue is used to queue up async requests that must be + * serialized. For example writing buffers into a socket must be + * serialized. Writing a large lump of data into a socket can require + * multiple write(2) or send(2) system calls. If more than one async + * request is outstanding to write large buffers into a socket, every + * request must individually be completed before the next one begins, + * even if multiple syscalls are required. + * + * Take a look at @ref tevent_queue_tutorial for more details. + * @{ + */ + +struct tevent_queue; +struct tevent_queue_entry; + +/** + * @brief Associate a custom tag with the queue entry. + * + * This tag can be then retrieved with tevent_queue_entry_get_tag() + * + * @param[in] qe The queue entry. + * + * @param[in] tag Custom tag. + */ +void tevent_queue_entry_set_tag(struct tevent_queue_entry *qe, uint64_t tag); + +/** + * @brief Get custom queue entry tag. + */ +uint64_t tevent_queue_entry_get_tag(const struct tevent_queue_entry *qe); + +typedef void (*tevent_trace_queue_callback_t)(struct tevent_queue_entry *qe, + enum tevent_event_trace_point, + void *private_data); + +/** + * Register a callback to be called at certain trace points of queue. + * + * @param[in] ev Event context + * @param[in] cb Trace callback + * @param[in] private_data Data to be passed to callback + * + * @note The callback will be called at trace points defined by + * tevent_event_trace_point. Call with NULL to reset. + */ +void tevent_set_trace_queue_callback(struct tevent_context *ev, + tevent_trace_queue_callback_t cb, + void *private_data); + +/** + * Retrieve the current trace callback of queue. + * + * @param[in] ev Event context + * @param[out] cb Registered trace callback + * @param[out] p_private_data Registered data to be passed to callback + * + * @note This can be used to allow one component that wants to + * register a callback to respect the callback that another component + * has already registered. + */ +void tevent_get_trace_queue_callback(struct tevent_context *ev, + tevent_trace_queue_callback_t *cb, + void *p_private_data); + +#ifdef DOXYGEN +/** + * @brief Create and start a tevent queue. + * + * @param[in] mem_ctx The talloc memory context to allocate the queue. + * + * @param[in] name The name to use to identify the queue. + * + * @return An allocated tevent queue on success, NULL on error. + * + * @see tevent_queue_start() + * @see tevent_queue_stop() + */ +struct tevent_queue *tevent_queue_create(TALLOC_CTX *mem_ctx, + const char *name); +#else +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__) +#endif + +/** + * @brief A callback trigger function run by the queue. + * + * @param[in] req The tevent request the trigger function is executed on. + * + * @param[in] private_data The private data pointer specified by + * tevent_queue_add(). + * + * @see tevent_queue_add() + * @see tevent_queue_add_entry() + * @see tevent_queue_add_optimize_empty() + */ +typedef void (*tevent_queue_trigger_fn_t)(struct tevent_req *req, + void *private_data); + +/** + * @brief Add a tevent request to the queue. + * + * @param[in] queue The queue to add the request. + * + * @param[in] ev The event handle to use for the request. + * + * @param[in] req The tevent request to add to the queue. + * + * @param[in] trigger The function triggered by the queue when the request + * is called. Since tevent 0.9.14 it's possible to + * pass NULL, in order to just add a "blocker" to the + * queue. + * + * @param[in] private_data The private data passed to the trigger function. + * + * @return True if the request has been successfully added, false + * otherwise. + */ +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); + +/** + * @brief Add a tevent request to the queue. + * + * The request can be removed from the queue by calling talloc_free() + * (or a similar function) on the returned queue entry. This + * is the only difference to tevent_queue_add(). + * + * @param[in] queue The queue to add the request. + * + * @param[in] ev The event handle to use for the request. + * + * @param[in] req The tevent request to add to the queue. + * + * @param[in] trigger The function triggered by the queue when the request + * is called. Since tevent 0.9.14 it's possible to + * pass NULL, in order to just add a "blocker" to the + * queue. + * + * @param[in] private_data The private data passed to the trigger function. + * + * @return a pointer to the tevent_queue_entry if the request + * has been successfully added, NULL otherwise. + * + * @see tevent_queue_add() + * @see tevent_queue_add_optimize_empty() + */ +struct tevent_queue_entry *tevent_queue_add_entry( + struct tevent_queue *queue, + struct tevent_context *ev, + struct tevent_req *req, + tevent_queue_trigger_fn_t trigger, + void *private_data); + +/** + * @brief Add a tevent request to the queue using a possible optimization. + * + * This tries to optimize for the empty queue case and may calls + * the trigger function directly. This is the only difference compared + * to tevent_queue_add_entry(). + * + * The caller needs to be prepared that the trigger function has + * already called tevent_req_notify_callback(), tevent_req_error(), + * tevent_req_done() or a similar function. + * + * The trigger function has no chance to see the returned + * queue_entry in the optimized case. + * + * The request can be removed from the queue by calling talloc_free() + * (or a similar function) on the returned queue entry. + * + * @param[in] queue The queue to add the request. + * + * @param[in] ev The event handle to use for the request. + * + * @param[in] req The tevent request to add to the queue. + * + * @param[in] trigger The function triggered by the queue when the request + * is called. Since tevent 0.9.14 it's possible to + * pass NULL, in order to just add a "blocker" to the + * queue. + * + * @param[in] private_data The private data passed to the trigger function. + * + * @return a pointer to the tevent_queue_entry if the request + * has been successfully added, NULL otherwise. + * + * @see tevent_queue_add() + * @see tevent_queue_add_entry() + */ +struct tevent_queue_entry *tevent_queue_add_optimize_empty( + struct tevent_queue *queue, + struct tevent_context *ev, + struct tevent_req *req, + tevent_queue_trigger_fn_t trigger, + void *private_data); + +/** + * @brief Untrigger an already triggered queue entry. + * + * If a trigger function detects that it needs to remain + * in the queue, it needs to call tevent_queue_stop() + * followed by tevent_queue_entry_untrigger(). + * + * @note In order to call tevent_queue_entry_untrigger() + * the queue must be already stopped and the given queue_entry + * must be the first one in the queue! Otherwise it calls abort(). + * + * @note You can't use this together with tevent_queue_add_optimize_empty() + * because the trigger function don't have access to the quene entry + * in the case of an empty queue. + * + * @param[in] queue_entry The queue entry to rearm. + * + * @see tevent_queue_add_entry() + * @see tevent_queue_stop() + */ +void tevent_queue_entry_untrigger(struct tevent_queue_entry *entry); + +/** + * @brief Start a tevent queue. + * + * The queue is started by default. + * + * @param[in] queue The queue to start. + */ +void tevent_queue_start(struct tevent_queue *queue); + +/** + * @brief Stop a tevent queue. + * + * The queue is started by default. + * + * @param[in] queue The queue to stop. + */ +void tevent_queue_stop(struct tevent_queue *queue); + +/** + * @brief Get the length of the queue. + * + * @param[in] queue The queue to get the length from. + * + * @return The number of elements. + */ +size_t tevent_queue_length(struct tevent_queue *queue); + +/** + * @brief Is the tevent queue running. + * + * The queue is started by default. + * + * @param[in] queue The queue. + * + * @return Whether the queue is running or not.. + */ +bool tevent_queue_running(struct tevent_queue *queue); + +/** + * @brief Create a tevent subrequest that waits in a tevent_queue + * + * The idea is that always the same syntax for tevent requests. + * + * @param[in] mem_ctx The talloc memory context to use. + * + * @param[in] ev The event handle to setup the request. + * + * @param[in] queue The queue to wait in. + * + * @return The new subrequest, NULL on error. + * + * @see tevent_queue_wait_recv() + */ +struct tevent_req *tevent_queue_wait_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + struct tevent_queue *queue); + +/** + * @brief Check if we no longer need to wait in the queue. + * + * This function needs to be called in the callback function set after calling + * tevent_queue_wait_send(). + * + * @param[in] req The tevent request to check. + * + * @return True on success, false otherwise. + * + * @see tevent_queue_wait_send() + */ +bool tevent_queue_wait_recv(struct tevent_req *req); + +typedef int (*tevent_nesting_hook)(struct tevent_context *ev, + void *private_data, + uint32_t level, + bool begin, + void *stack_ptr, + const char *location); + +/** + * @brief Create a tevent_thread_proxy for message passing between threads. + * + * The tevent_context must have been allocated on the NULL + * talloc context, and talloc_disable_null_tracking() must + * have been called. + * + * @param[in] dest_ev_ctx The tevent_context to receive events. + * + * @return An allocated tevent_thread_proxy, NULL on error. + * If tevent was compiled without PTHREAD support + * NULL is always returned and errno set to ENOSYS. + * + * @see tevent_thread_proxy_schedule() + */ +struct tevent_thread_proxy *tevent_thread_proxy_create( + struct tevent_context *dest_ev_ctx); + +/** + * @brief Schedule an immediate event on an event context from another thread. + * + * Causes dest_ev_ctx, being run by another thread, to receive an + * immediate event calling the handler with the *pp_private parameter. + * + * *pp_im must be a pointer to an immediate event talloced on a context owned + * by the calling thread, or the NULL context. Ownership will + * be transferred to the tevent_thread_proxy and *pp_im will be returned as NULL. + * + * *pp_private_data must be a talloced area of memory with no destructors. + * Ownership of this memory will be transferred to the tevent library and + * *pp_private_data will be set to NULL on successful completion of + * the call. Set pp_private to NULL if no parameter transfer + * needed (a pure callback). This is an asynchronous request, caller + * does not wait for callback to be completed before returning. + * + * @param[in] tp The tevent_thread_proxy to use. + * + * @param[in] pp_im Pointer to immediate event pointer. + * + * @param[in] handler The function that will be called. + * + * @param[in] pp_private_data The talloced memory to transfer. + * + * @see tevent_thread_proxy_create() + */ +void tevent_thread_proxy_schedule(struct tevent_thread_proxy *tp, + struct tevent_immediate **pp_im, + tevent_immediate_handler_t handler, + void *pp_private_data); + +/* + * @brief Create a context for threaded activation of immediates + * + * A tevent_treaded_context provides a link into an event + * context. Using tevent_threaded_schedule_immediate, it is possible + * to activate an immediate event from within a thread. + * + * It is the duty of the caller of tevent_threaded_context_create() to + * keep the event context around longer than any + * tevent_threaded_context. tevent will abort if ev is talloc_free'ed + * with an active tevent_threaded_context. + * + * If tevent is build without pthread support, this always returns + * NULL with errno=ENOSYS. + * + * @param[in] mem_ctx The talloc memory context to use. + * @param[in] ev The event context to link this to. + * @return The threaded context, or NULL with errno set. + * + * @see tevent_threaded_schedule_immediate() + * + * @note Available as of tevent 0.9.30 + */ +struct tevent_threaded_context *tevent_threaded_context_create( + TALLOC_CTX *mem_ctx, struct tevent_context *ev); + +#ifdef DOXYGEN +/* + * @brief Activate an immediate from a thread + * + * Activate an immediate from within a thread. + * + * This routine does not watch out for talloc hierarchies. This means + * that it is highly recommended to create the tevent_immediate in the + * thread owning tctx, allocate a threaded job description for the + * thread, hand over both pointers to a helper thread and not touch it + * in the main thread at all anymore. + * + * tevent_threaded_schedule_immediate is intended as a job completion + * indicator for simple threaded helpers. + * + * Please be aware that tevent_threaded_schedule_immediate is very + * picky about its arguments: An immediate may not already be + * activated and the handler must exist. With + * tevent_threaded_schedule_immediate memory ownership is transferred + * to the main thread holding the tevent context behind tctx, the + * helper thread can't access it anymore. + * + * @param[in] tctx The threaded context to go through + * @param[in] im The immediate event to activate + * @param[in] handler The immediate handler to call in the main thread + * @param[in] private_data Pointer for the immediate handler + * + * @see tevent_threaded_context_create() + * + * @note Available as of tevent 0.9.30 + */ +void tevent_threaded_schedule_immediate(struct tevent_threaded_context *tctx, + struct tevent_immediate *im, + tevent_immediate_handler_t handler, + void *private_data); +#else +void _tevent_threaded_schedule_immediate(struct tevent_threaded_context *tctx, + struct tevent_immediate *im, + tevent_immediate_handler_t handler, + void *private_data, + const char *handler_name, + const char *location); +#define tevent_threaded_schedule_immediate(tctx, im, handler, private_data) \ + _tevent_threaded_schedule_immediate(tctx, im, handler, private_data, \ + #handler, __location__); +#endif + +#ifdef TEVENT_DEPRECATED +#ifndef _DEPRECATED_ +#if __has_attribute(deprecated) || (__GNUC__ >= 3) +#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); +const struct tevent_ops *tevent_find_ops_byname(const char *name); + +/* @} */ + +#ifdef TEVENT_DEPRECATED +/** + * @defgroup tevent_wrapper_ops The tevent wrapper operation functions + * @ingroup tevent + * + * The following structure and registration functions are exclusively + * needed for people writing wrapper functions for event handlers + * e.g. wrappers can be used for debugging/profiling or impersonation. + * + * There is nothing useful for normal tevent user in here. + * + * @note That the close_fn() on tevent_fd is *NOT* wrapped! + * + * @see tevent_context_wrapper_create + * @see tevent_fd_set_auto_close + * @{ + */ + +struct tevent_wrapper_ops { + const char *name; + + bool (*before_use)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + const char *location); + void (*after_use)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + const char *location); + + void (*before_fd_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_fd *fde, + uint16_t flags, + const char *handler_name, + const char *location); + void (*after_fd_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_fd *fde, + uint16_t flags, + const char *handler_name, + const char *location); + + void (*before_timer_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_timer *te, + struct timeval requested_time, + struct timeval trigger_time, + const char *handler_name, + const char *location); + void (*after_timer_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_timer *te, + struct timeval requested_time, + struct timeval trigger_time, + const char *handler_name, + const char *location); + + void (*before_immediate_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_immediate *im, + const char *handler_name, + const char *location); + void (*after_immediate_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_immediate *im, + const char *handler_name, + const char *location); + + void (*before_signal_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_signal *se, + int signum, + int count, + void *siginfo, + const char *handler_name, + const char *location); + void (*after_signal_handler)(struct tevent_context *wrap_ev, + void *private_state, + struct tevent_context *main_ev, + struct tevent_signal *se, + int signum, + int count, + void *siginfo, + const char *handler_name, + const char *location); +}; + +#ifdef DOXYGEN +/** + * @brief Create a wrapper tevent_context. + * + * @param[in] main_ev The main event context to work on. + * + * @param[in] mem_ctx The talloc memory context to use. + * + * @param[in] ops The tevent_wrapper_ops function table. + * + * @param[out] private_state The private state use by the wrapper functions. + * + * @param[in] private_type The talloc type of the private_state. + * + * @return The wrapper event context, NULL on error. + * + * @note Available as of tevent 0.9.37 + * @note Deprecated as of tevent 0.9.38 + */ +struct tevent_context *tevent_context_wrapper_create(struct tevent_context *main_ev, + TALLOC_CTX *mem_ctx, + const struct tevent_wrapper_ops *ops, + void **private_state, + const char *private_type); +#else +struct tevent_context *_tevent_context_wrapper_create(struct tevent_context *main_ev, + TALLOC_CTX *mem_ctx, + const struct tevent_wrapper_ops *ops, + void *pstate, + size_t psize, + const char *type, + const char *location) _DEPRECATED_; +#define tevent_context_wrapper_create(main_ev, mem_ctx, ops, state, type) \ + _tevent_context_wrapper_create(main_ev, mem_ctx, ops, \ + state, sizeof(type), #type, __location__) +#endif + +/** + * @brief Check if the event context is a wrapper event context. + * + * @param[in] ev The event context to work on. + * + * @return Is a wrapper (true), otherwise (false). + * + * @see tevent_context_wrapper_create() + * + * @note Available as of tevent 0.9.37 + * @note Deprecated as of tevent 0.9.38 + */ +bool tevent_context_is_wrapper(struct tevent_context *ev) _DEPRECATED_; + +#ifdef DOXYGEN +/** + * @brief Prepare the environment of a (wrapper) event context. + * + * A caller might call this before passing a wrapper event context + * to a tevent_req based *_send() function. + * + * The wrapper event context might do something like impersonation. + * + * tevent_context_push_use() must always be used in combination + * with tevent_context_pop_use(). + * + * There is a global stack of currently active/busy wrapper event contexts. + * Each wrapper can only appear once on that global stack! + * The stack size is limited to 32 elements, which should be enough + * for all useful scenarios. + * + * In addition to an explicit tevent_context_push_use() also + * the invocation of an immediate, timer or fd handler implicitly + * pushes the wrapper on the stack. + * + * Therefore there are some strict constraints for the usage of + * tevent_context_push_use(): + * - It must not be called from within an event handler + * that already acts on the wrapper. + * - tevent_context_pop_use() must be called before + * leaving the code block that called tevent_context_push_use(). + * - The caller is responsible ensure the correct stack ordering + * - Any violation of these constraints results in calling + * the abort handler of the given tevent context. + * + * Calling tevent_context_push_use() on a raw event context + * still consumes an element on the stack, but it's otherwise + * a no-op. + * + * If tevent_context_push_use() returns false, it means + * that the wrapper's before_use() hook returned this failure, + * in that case you must not call tevent_context_pop_use() as + * the wrapper is not pushed onto the stack. + * + * @param[in] ev The event context to work on. + * + * @return Success (true) or failure (false). + * + * @note This is only needed if wrapper event contexts are in use. + * + * @see tevent_context_pop_use + * + * @note Available as of tevent 0.9.37 + * @note Deprecated as of tevent 0.9.38 + */ +bool tevent_context_push_use(struct tevent_context *ev); +#else +bool _tevent_context_push_use(struct tevent_context *ev, + const char *location) _DEPRECATED_; +#define tevent_context_push_use(ev) \ + _tevent_context_push_use(ev, __location__) +#endif + +#ifdef DOXYGEN +/** + * @brief Release the environment of a (wrapper) event context. + * + * The wrapper event context might undo something like impersonation. + * + * This must be called after a succesful tevent_context_push_use(). + * Any ordering violation results in calling + * the abort handler of the given tevent context. + * + * This basically calls the wrapper's after_use() hook. + * + * @param[in] ev The event context to work on. + * + * @note This is only needed if wrapper event contexts are in use. + * + * @see tevent_context_push_use + * + * @note Available as of tevent 0.9.37 + * @note Deprecated as of tevent 0.9.38 + */ +void tevent_context_pop_use(struct tevent_context *ev); +#else +void _tevent_context_pop_use(struct tevent_context *ev, + const char *location) _DEPRECATED_; +#define tevent_context_pop_use(ev) \ + _tevent_context_pop_use(ev, __location__) +#endif + +/** + * @brief Check is the two context pointers belong to the same low level loop + * + * With the introduction of wrapper contexts it's not trivial + * to check if two context pointers belong to the same low level + * event loop. Some code may need to know this in order + * to make some caching decisions. + * + * @param[in] ev1 The first event context. + * @param[in] ev2 The second event context. + * + * @return true if both contexts belong to the same (still existing) context + * loop, false otherwise. + * + * @see tevent_context_wrapper_create + * + * @note Available as of tevent 0.9.37 + * @note Deprecated as of tevent 0.9.38 + */ +bool tevent_context_same_loop(struct tevent_context *ev1, + struct tevent_context *ev2) _DEPRECATED_; + +/* @} */ +#endif /* TEVENT_DEPRECATED */ + +/** + * @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__ */ |