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a78cd2a24b
metze
354 lines
8.8 KiB
C
354 lines
8.8 KiB
C
/*
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Unix SMB/CIFS implementation.
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Infrastructure for async requests
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Copyright (C) Volker Lendecke 2008
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Copyright (C) Stefan Metzmacher 2009
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** NOTE! The following LGPL license applies to the tevent
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** library. This does NOT imply that all of Samba is released
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** under the LGPL
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 3 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include "tevent.h"
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#include "tevent_internal.h"
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#include "tevent_util.h"
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/**
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* @brief The default print function for creating debug messages
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* @param[in] req The request to be printed
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* @param[in] mem_ctx The memory context for the result
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* @retval Text representation of req
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*
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* The function should not be used by users of the asynx API,
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* but custom print function can use it and append custom text
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* to the string.
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*/
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char *tevent_req_default_print(struct tevent_req *req, TALLOC_CTX *mem_ctx)
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{
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return talloc_asprintf(mem_ctx,
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"tevent_req[%p/%s]: state[%d] error[%lld (0x%llX)] "
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" state[%s (%p)] timer[%p]",
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req, req->internal.location,
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req->internal.state,
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(unsigned long long)req->internal.error,
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(unsigned long long)req->internal.error,
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talloc_get_name(req->data),
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req->data,
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req->internal.timer
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);
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}
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/**
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* @brief Print an tevent_req structure in debug messages
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* @param[in] mem_ctx The memory context for the result
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* @param[in] req The request to be printed
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* @retval Text representation of req
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*
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* This function should be used by callers of the async API
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*/
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char *tevent_req_print(TALLOC_CTX *mem_ctx, struct tevent_req *req)
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{
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if (!req->private_print) {
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return tevent_req_default_print(req, mem_ctx);
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}
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return req->private_print(req, mem_ctx);
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}
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/**
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* @brief Create an async request
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* @param[in] mem_ctx The memory context for the result
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* @param[in] ev The event context this async request will be driven by
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* @retval A new async request
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*
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* The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS
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*/
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struct tevent_req *_tevent_req_create(TALLOC_CTX *mem_ctx,
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void *pdata,
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size_t data_size,
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const char *type,
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const char *location)
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{
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struct tevent_req *req;
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void **ppdata = (void **)pdata;
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void *data;
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req = talloc_zero(mem_ctx, struct tevent_req);
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if (req == NULL) {
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return NULL;
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}
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req->internal.private_type = type;
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req->internal.location = location;
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req->internal.state = TEVENT_REQ_IN_PROGRESS;
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data = talloc_size(req, data_size);
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if (data == NULL) {
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talloc_free(req);
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return NULL;
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}
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talloc_set_name_const(data, type);
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req->data = data;
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*ppdata = data;
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return req;
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}
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static void tevent_req_finish(struct tevent_req *req, enum tevent_req_state state)
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{
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req->internal.state = state;
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if (req->async.fn != NULL) {
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req->async.fn(req);
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}
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}
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/**
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* @brief An async request has successfully finished
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* @param[in] req The finished request
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*
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* async_req_done is to be used by implementors of async requests. When a
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* request is successfully finished, this function calls the user's completion
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* function.
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*/
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void tevent_req_done(struct tevent_req *req)
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{
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tevent_req_finish(req, TEVENT_REQ_DONE);
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}
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/**
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* @brief An async request has seen an error
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* @param[in] req The request with an error
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* @param[in] error The error code
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*
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* tevent_req_done is to be used by implementors of async requests. When a
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* request can not successfully completed, the implementation should call this
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* function with the appropriate status code.
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*
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* If error is 0 the function returns false and does nothing more.
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*
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* Call pattern would be
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* \code
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* int error = first_function();
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* if (tevent_req_error(req, error)) {
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* return;
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* }
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*
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* error = second_function();
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* if (tevent_req_error(req, error)) {
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* return;
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* }
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*
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* tevent_req_done(req);
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* return;
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* \endcode
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*/
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bool tevent_req_error(struct tevent_req *req, uint64_t error)
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{
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if (error == 0) {
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return false;
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}
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req->internal.error = error;
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tevent_req_finish(req, TEVENT_REQ_USER_ERROR);
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return true;
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}
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/**
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* @brief Helper function for nomem check
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* @param[in] p The pointer to be checked
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* @param[in] req The request being processed
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*
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* Convenience helper to easily check alloc failure within a callback
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* implementing the next step of an async request.
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*
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* Call pattern would be
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* \code
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* p = talloc(mem_ctx, bla);
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* if (tevent_req_nomem(p, req)) {
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* return;
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* }
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* \endcode
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*/
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bool tevent_req_nomem(const void *p, struct tevent_req *req)
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{
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if (p != NULL) {
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return false;
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}
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tevent_req_finish(req, TEVENT_REQ_NO_MEMORY);
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return true;
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}
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/**
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* @brief Timed event callback
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* @param[in] ev Event context
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* @param[in] te The timed event
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* @param[in] now zero time
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* @param[in] priv The async request to be finished
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*/
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static void tevent_req_trigger(struct tevent_context *ev,
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struct tevent_timer *te,
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struct timeval zero,
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void *private_data)
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{
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struct tevent_req *req = talloc_get_type(private_data,
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struct tevent_req);
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talloc_free(req->internal.trigger);
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req->internal.trigger = NULL;
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tevent_req_finish(req, req->internal.state);
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}
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/**
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* @brief Finish a request before the caller had the change to set the callback
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* @param[in] req The finished request
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* @param[in] ev The tevent_context for the timed event
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* @retval On success req will be returned,
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* on failure req will be destroyed
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*
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* An implementation of an async request might find that it can either finish
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* the request without waiting for an external event, or it can't even start
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* the engine. To present the illusion of a callback to the user of the API,
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* the implementation can call this helper function which triggers an
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* immediate timed event. This way the caller can use the same calling
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* conventions, independent of whether the request was actually deferred.
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*/
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struct tevent_req *tevent_req_post(struct tevent_req *req,
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struct tevent_context *ev)
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{
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req->internal.trigger = tevent_add_timer(ev, req, tevent_timeval_zero(),
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tevent_req_trigger, req);
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if (!req->internal.trigger) {
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talloc_free(req);
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return NULL;
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}
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return req;
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}
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bool tevent_req_is_in_progress(struct tevent_req *req)
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{
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if (req->internal.state == TEVENT_REQ_IN_PROGRESS) {
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return true;
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}
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return false;
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}
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/**
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* @brief This function destroys the attached private data
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* @param[in] req The finished request
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*
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* This function can be called as last action of a _recv()
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* function, it destroys the data attached to the tevent_req.
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*/
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void tevent_req_received(struct tevent_req *req)
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{
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TALLOC_FREE(req->data);
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req->private_print = NULL;
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TALLOC_FREE(req->internal.trigger);
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TALLOC_FREE(req->internal.timer);
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req->internal.state = TEVENT_REQ_RECEIVED;
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}
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bool tevent_req_poll(struct tevent_req *req,
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struct tevent_context *ev)
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{
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while (tevent_req_is_in_progress(req)) {
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int ret;
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ret = tevent_loop_once(ev);
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if (ret != 0) {
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return false;
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}
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}
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return true;
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}
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bool tevent_req_is_error(struct tevent_req *req, enum tevent_req_state *state,
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uint64_t *error)
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{
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if (req->internal.state == TEVENT_REQ_DONE) {
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return false;
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}
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if (req->internal.state == TEVENT_REQ_USER_ERROR) {
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*error = req->internal.error;
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}
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*state = req->internal.state;
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return true;
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}
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static void tevent_req_timedout(struct tevent_context *ev,
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struct tevent_timer *te,
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struct timeval now,
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void *private_data)
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{
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struct tevent_req *req = talloc_get_type(private_data,
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struct tevent_req);
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TALLOC_FREE(req->internal.timer);
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tevent_req_finish(req, TEVENT_REQ_TIMED_OUT);
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}
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bool tevent_req_set_endtime(struct tevent_req *req,
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struct tevent_context *ev,
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struct timeval endtime)
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{
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TALLOC_FREE(req->internal.timer);
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req->internal.timer = tevent_add_timer(ev, req, endtime,
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tevent_req_timedout,
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req);
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if (tevent_req_nomem(req->internal.timer, req)) {
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return false;
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}
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return true;
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}
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void tevent_req_set_callback(struct tevent_req *req, tevent_req_fn fn, void *pvt)
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{
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req->async.fn = fn;
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req->async.private_data = pvt;
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}
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void *_tevent_req_callback_data(struct tevent_req *req)
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{
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return req->async.private_data;
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}
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void *_tevent_req_data(struct tevent_req *req)
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{
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return req->data;
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}
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void tevent_req_set_print_fn(struct tevent_req *req, tevent_req_print_fn fn)
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{
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req->private_print = fn;
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}
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