1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
|
/*
Unix SMB/CIFS implementation.
Infrastructure for async requests
Copyright (C) Volker Lendecke 2008
Copyright (C) Stefan Metzmacher 2009
** 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/>.
*/
#include "replace.h"
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"
/**
* @brief The default print function for creating debug messages
* @param[in] req The request to be printed
* @param[in] mem_ctx The memory context for the result
* @retval Text representation of req
*
* The function should not be used by users of the asynx API,
* but custom print function can use it and append custom text
* to the string.
*/
char *tevent_req_default_print(struct tevent_req *req, TALLOC_CTX *mem_ctx)
{
return talloc_asprintf(mem_ctx,
"tevent_req[%p/%s]: state[%d] error[%lld (0x%llX)] "
" state[%s (%p)] timer[%p]",
req, req->internal.create_location,
req->internal.state,
(unsigned long long)req->internal.error,
(unsigned long long)req->internal.error,
talloc_get_name(req->data),
req->data,
req->internal.timer
);
}
/**
* @brief Print an tevent_req structure in debug messages
* @param[in] mem_ctx The memory context for the result
* @param[in] req The request to be printed
* @retval Text representation of req
*
* This function should be used by callers of the async API
*/
char *tevent_req_print(TALLOC_CTX *mem_ctx, struct tevent_req *req)
{
if (!req->private_print) {
return tevent_req_default_print(req, mem_ctx);
}
return req->private_print(req, mem_ctx);
}
/**
* @brief Create an async request
* @param[in] mem_ctx The memory context for the result
* @param[in] ev The event context this async request will be driven by
* @retval A new async request
*
* The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS
*/
struct tevent_req *_tevent_req_create(TALLOC_CTX *mem_ctx,
void *pdata,
size_t data_size,
const char *type,
const char *location)
{
struct tevent_req *req;
void **ppdata = (void **)pdata;
void *data;
req = talloc_zero(mem_ctx, struct tevent_req);
if (req == NULL) {
return NULL;
}
req->internal.private_type = type;
req->internal.create_location = location;
req->internal.finish_location = NULL;
req->internal.state = TEVENT_REQ_IN_PROGRESS;
req->internal.trigger = tevent_create_immediate(req);
if (!req->internal.trigger) {
talloc_free(req);
return NULL;
}
data = talloc_zero_size(req, data_size);
if (data == NULL) {
talloc_free(req);
return NULL;
}
talloc_set_name_const(data, type);
req->data = data;
*ppdata = data;
return req;
}
void _tevent_req_notify_callback(struct tevent_req *req, const char *location)
{
req->internal.finish_location = location;
if (req->async.fn != NULL) {
req->async.fn(req);
}
}
static void tevent_req_finish(struct tevent_req *req,
enum tevent_req_state state,
const char *location)
{
req->internal.state = state;
_tevent_req_notify_callback(req, location);
}
/**
* @brief An async request has successfully finished
* @param[in] req The finished request
*
* tevent_req_done is to be used by implementors of async requests. When a
* request is successfully finished, this function calls the user's completion
* function.
*/
void _tevent_req_done(struct tevent_req *req,
const char *location)
{
tevent_req_finish(req, TEVENT_REQ_DONE, location);
}
/**
* @brief An async request has seen an error
* @param[in] req The request with an error
* @param[in] error The error code
*
* tevent_req_done 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.
*
* Call pattern would be
* \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,
const char *location)
{
if (error == 0) {
return false;
}
req->internal.error = error;
tevent_req_finish(req, TEVENT_REQ_USER_ERROR, location);
return true;
}
/**
* @brief Helper function for nomem check
* @param[in] p The pointer to be checked
* @param[in] req The request being processed
*
* Convenience helper to easily check alloc failure within a callback
* implementing the next step of an async request.
*
* Call pattern would be
* \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,
const char *location)
{
if (p != NULL) {
return false;
}
tevent_req_finish(req, TEVENT_REQ_NO_MEMORY, location);
return true;
}
/**
* @brief Immediate event callback
* @param[in] ev Event context
* @param[in] im The immediate event
* @param[in] priv The async request to be finished
*/
static void tevent_req_trigger(struct tevent_context *ev,
struct tevent_immediate *im,
void *private_data)
{
struct tevent_req *req = talloc_get_type(private_data,
struct tevent_req);
tevent_req_finish(req, req->internal.state,
req->internal.finish_location);
}
/**
* @brief Finish a request before the caller had the change to set the callback
* @param[in] req The finished request
* @param[in] ev The tevent_context for the timed event
* @retval req will be returned
*
* An implementation of an async request might find that it can either finish
* the request without waiting for an external event, or it can't even start
* the engine. To present the illusion of a callback to the user of the API,
* the implementation can call this helper function which triggers an
* immediate timed event. This way the caller can use the same calling
* conventions, independent of whether the request was actually deferred.
*/
struct tevent_req *tevent_req_post(struct tevent_req *req,
struct tevent_context *ev)
{
tevent_schedule_immediate(req->internal.trigger,
ev, tevent_req_trigger, req);
return req;
}
/**
* @brief This function destroys the attached private data
* @param[in] req The request to poll
* @retval The boolean form of "is in progress".
*
* This function can be used to ask if the given request
* is still in progress.
*
* This function is typically used by sync wrapper functions.
*/
bool tevent_req_is_in_progress(struct tevent_req *req)
{
if (req->internal.state == TEVENT_REQ_IN_PROGRESS) {
return true;
}
return false;
}
/**
* @brief This function destroys the attached private data
* @param[in] req The finished request
*
* This function can be called as last action of a _recv()
* function, it destroys the data attached to the tevent_req.
*/
void tevent_req_received(struct tevent_req *req)
{
TALLOC_FREE(req->data);
req->private_print = NULL;
TALLOC_FREE(req->internal.trigger);
TALLOC_FREE(req->internal.timer);
req->internal.state = TEVENT_REQ_RECEIVED;
}
/**
* @brief This function destroys the attached private data
* @param[in] req The request to poll
* @param[in] ev The tevent_context to be used
* @retval If a critical error has happened in the
* tevent loop layer false is returned.
* Otherwise true is returned.
* This is not the return value of the given request!
*
* This function can be used to actively poll for the
* given request to finish.
*
* Note: this should only be used if the given tevent context
* was created by the caller, to avoid event loop nesting.
*
* This function is typically used by sync wrapper functions.
*/
bool tevent_req_poll(struct tevent_req *req,
struct tevent_context *ev)
{
while (tevent_req_is_in_progress(req)) {
int ret;
ret = tevent_loop_once(ev);
if (ret != 0) {
return false;
}
}
return true;
}
bool tevent_req_is_error(struct tevent_req *req, enum tevent_req_state *state,
uint64_t *error)
{
if (req->internal.state == TEVENT_REQ_DONE) {
return false;
}
if (req->internal.state == TEVENT_REQ_USER_ERROR) {
*error = req->internal.error;
}
*state = req->internal.state;
return true;
}
static void tevent_req_timedout(struct tevent_context *ev,
struct tevent_timer *te,
struct timeval now,
void *private_data)
{
struct tevent_req *req = talloc_get_type(private_data,
struct tevent_req);
TALLOC_FREE(req->internal.timer);
tevent_req_finish(req, TEVENT_REQ_TIMED_OUT, __FUNCTION__);
}
bool tevent_req_set_endtime(struct tevent_req *req,
struct tevent_context *ev,
struct timeval endtime)
{
TALLOC_FREE(req->internal.timer);
req->internal.timer = tevent_add_timer(ev, req, endtime,
tevent_req_timedout,
req);
if (tevent_req_nomem(req->internal.timer, req)) {
return false;
}
return true;
}
void tevent_req_set_callback(struct tevent_req *req, tevent_req_fn fn, void *pvt)
{
req->async.fn = fn;
req->async.private_data = pvt;
}
void *_tevent_req_callback_data(struct tevent_req *req)
{
return req->async.private_data;
}
void *_tevent_req_data(struct tevent_req *req)
{
return req->data;
}
/**
* @brief This function sets a print function for the given request
* @param[in] req The given request
* @param[in] fn A pointer to the print function
*
* 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.
*
* Note: this function should only be used for debugging.
*/
void tevent_req_set_print_fn(struct tevent_req *req, tevent_req_print_fn fn)
{
req->private_print = fn;
}
|