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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:44:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:44:55 +0000
commitbfe2e03d5ecddce1b9666a58a57e66078a737ea1 (patch)
tree4a4130aca118d9aaaf1494e0e6a5015a0aa409b5 /tevent.h
parentInitial commit. (diff)
downloadtevent-bfe2e03d5ecddce1b9666a58a57e66078a737ea1.tar.xz
tevent-bfe2e03d5ecddce1b9666a58a57e66078a737ea1.zip
Adding upstream version 0.14.1.upstream/0.14.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
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1 files changed, 2960 insertions, 0 deletions
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+/*
+ 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__ */