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samba-mirror/lib/tevent/tevent.h
Stefan Metzmacher 168079b2c3 tevent: deprecate tevent_wrapper api again 
Samba doesn't use it anymore and we don't want to
invite new users of that api without further discussion.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Sat Jan 12 03:12:09 CET 2019 on sn-devel-144
2019-01-12 03:12:09 +01:00

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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 <stdbool.h>
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
#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);
#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
#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 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);
/**
* @}
*/
/**
* @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_req *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 timval with the given offset in the future.
*/
struct timeval tevent_timeval_current_ofs(uint32_t secs, uint32_t usecs);
/* @} */
/**
* @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;
#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_
#ifdef HAVE___ATTRIBUTE__
#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);
/* @} */
#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__ */
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