libsigrok
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros
session.c
Go to the documentation of this file.
1 /*
2  * This file is part of the sigrok project.
3  *
4  * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
5  *
6  * This program is free software: you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation, either version 3 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program. If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <unistd.h>
23 #include <string.h>
24 #include <glib.h>
25 #include "sigrok.h"
26 #include "sigrok-internal.h"
27 
28 /* demo.c. TODO: Should not be global! */
29 extern SR_PRIV GIOChannel channels[2];
30 
31 struct source {
32  int fd;
33  int events;
34  int timeout;
36  void *cb_data;
37 };
38 
39 /* There can only be one session at a time. */
40 /* 'session' is not static, it's used elsewhere (via 'extern'). */
42 static int num_sources = 0;
43 
44 static struct source *sources = NULL;
45 static int source_timeout = -1;
46 
47 /**
48  * Create a new session.
49  *
50  * TODO: Should it use the file-global "session" variable or take an argument?
51  * The same question applies to all the other session functions.
52  *
53  * @return A pointer to the newly allocated session, or NULL upon errors.
54  */
56 {
57  if (!(session = g_try_malloc0(sizeof(struct sr_session)))) {
58  sr_err("session: %s: session malloc failed", __func__);
59  return NULL; /* TODO: SR_ERR_MALLOC? */
60  }
61 
62  return session;
63 }
64 
65 /**
66  * Destroy the current session.
67  *
68  * This frees up all memory used by the session.
69  *
70  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
71  */
73 {
74  if (!session) {
75  sr_err("session: %s: session was NULL", __func__);
76  return SR_ERR_BUG;
77  }
78 
79  g_slist_free(session->devs);
80  session->devs = NULL;
81 
82  /* TODO: Error checks needed? */
83 
84  /* TODO: Loop over protocol decoders and free them. */
85 
86  g_free(session);
87  session = NULL;
88 
89  return SR_OK;
90 }
91 
92 /**
93  * Remove all the devices from the current session. TODO?
94  *
95  * The session itself (i.e., the struct sr_session) is not free'd and still
96  * exists after this function returns.
97  *
98  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
99  */
101 {
102  if (!session) {
103  sr_err("session: %s: session was NULL", __func__);
104  return SR_ERR_BUG;
105  }
106 
107  g_slist_free(session->devs);
108  session->devs = NULL;
109 
110  return SR_OK;
111 }
112 
113 /**
114  * Add a device to the current session.
115  *
116  * @param dev The device to add to the current session. Must not be NULL.
117  * Also, dev->driver and dev->driver->dev_open must not be NULL.
118  *
119  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
120  */
122 {
123  int ret;
124 
125  if (!dev) {
126  sr_err("session: %s: dev was NULL", __func__);
127  return SR_ERR_ARG;
128  }
129 
130  if (!session) {
131  sr_err("session: %s: session was NULL", __func__);
132  return SR_ERR_BUG;
133  }
134 
135  /* If dev->driver is NULL, this is a virtual device. */
136  if (!dev->driver) {
137  sr_dbg("session: %s: dev->driver was NULL, this seems to be "
138  "a virtual device; continuing", __func__);
139  /* Just add the device, don't run dev_open(). */
140  session->devs = g_slist_append(session->devs, dev);
141  return SR_OK;
142  }
143 
144  /* dev->driver is non-NULL (i.e. we have a real device). */
145  if (!dev->driver->dev_open) {
146  sr_err("session: %s: dev->driver->dev_open was NULL",
147  __func__);
148  return SR_ERR_BUG;
149  }
150 
151  if ((ret = dev->driver->dev_open(dev->driver_index)) != SR_OK) {
152  sr_err("session: %s: dev_open failed (%d)", __func__, ret);
153  return ret;
154  }
155 
156  session->devs = g_slist_append(session->devs, dev);
157 
158  return SR_OK;
159 }
160 
161 /**
162  * Remove all datafeed callbacks in the current session.
163  *
164  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
165  */
167 {
168  if (!session) {
169  sr_err("session: %s: session was NULL", __func__);
170  return SR_ERR_BUG;
171  }
172 
173  g_slist_free(session->datafeed_callbacks);
174  session->datafeed_callbacks = NULL;
175 
176  return SR_OK;
177 }
178 
179 /**
180  * Add a datafeed callback to the current session.
181  *
182  * @param cb Function to call when a chunk of data is received.
183  * Must not be NULL.
184  *
185  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
186  */
188 {
189  if (!session) {
190  sr_err("session: %s: session was NULL", __func__);
191  return SR_ERR_BUG;
192  }
193 
194  if (!cb) {
195  sr_err("session: %s: cb was NULL", __func__);
196  return SR_ERR_ARG;
197  }
198 
199  session->datafeed_callbacks =
200  g_slist_append(session->datafeed_callbacks, cb);
201 
202  return SR_OK;
203 }
204 
205 /**
206  * TODO.
207  */
208 static int sr_session_run_poll(void)
209 {
210  GPollFD *fds, my_gpollfd;
211  int ret, i;
212 
213  fds = NULL;
214  while (session->running) {
215  /* TODO: Add comment. */
216  g_free(fds);
217 
218  /* Construct g_poll()'s array. */
219  if (!(fds = g_try_malloc(sizeof(GPollFD) * num_sources))) {
220  sr_err("session: %s: fds malloc failed", __func__);
221  return SR_ERR_MALLOC;
222  }
223  for (i = 0; i < num_sources; i++) {
224 #ifdef _WIN32
225  g_io_channel_win32_make_pollfd(&channels[0],
226  sources[i].events, &my_gpollfd);
227 #else
228  my_gpollfd.fd = sources[i].fd;
229  my_gpollfd.events = sources[i].events;
230  fds[i] = my_gpollfd;
231 #endif
232  }
233 
234  ret = g_poll(fds, num_sources, source_timeout);
235 
236  for (i = 0; i < num_sources; i++) {
237  if (fds[i].revents > 0 || (ret == 0
238  && source_timeout == sources[i].timeout)) {
239  /*
240  * Invoke the source's callback on an event,
241  * or if the poll timeout out and this source
242  * asked for that timeout.
243  */
244  if (!sources[i].cb(fds[i].fd, fds[i].revents,
245  sources[i].cb_data))
246  sr_session_source_remove(sources[i].fd);
247  }
248  }
249  }
250  g_free(fds);
251 
252  return SR_OK;
253 }
254 
255 /**
256  * Start a session.
257  *
258  * There can only be one session at a time.
259  *
260  * @return SR_OK upon success, SR_ERR upon errors.
261  */
263 {
264  struct sr_dev *dev;
265  GSList *l;
266  int ret;
267 
268  if (!session) {
269  sr_err("session: %s: session was NULL; a session must be "
270  "created first, before starting it.", __func__);
271  return SR_ERR_BUG;
272  }
273 
274  if (!session->devs) {
275  /* TODO: Actually the case? */
276  sr_err("session: %s: session->devs was NULL; a session "
277  "cannot be started without devices.", __func__);
278  return SR_ERR_BUG;
279  }
280 
281  /* TODO: Check driver_index validity? */
282 
283  sr_info("session: starting");
284 
285  for (l = session->devs; l; l = l->next) {
286  dev = l->data;
287  /* TODO: Check for dev != NULL. */
288  if ((ret = dev->driver->dev_acquisition_start(
289  dev->driver_index, dev)) != SR_OK) {
290  sr_err("session: %s: could not start an acquisition "
291  "(%d)", __func__, ret);
292  break;
293  }
294  }
295 
296  /* TODO: What if there are multiple devices? Which return code? */
297 
298  return ret;
299 }
300 
301 /**
302  * Run the session.
303  *
304  * TODO: Various error checks etc.
305  *
306  * @return SR_OK upon success, SR_ERR_BUG upon errors.
307  */
309 {
310  if (!session) {
311  sr_err("session: %s: session was NULL; a session must be "
312  "created first, before running it.", __func__);
313  return SR_ERR_BUG;
314  }
315 
316  if (!session->devs) {
317  /* TODO: Actually the case? */
318  sr_err("session: %s: session->devs was NULL; a session "
319  "cannot be run without devices.", __func__);
320  return SR_ERR_BUG;
321  }
322 
323  sr_info("session: running");
324  session->running = TRUE;
325 
326  /* Do we have real sources? */
327  if (num_sources == 1 && sources[0].fd == -1) {
328  /* Dummy source, freewheel over it. */
329  while (session->running)
330  sources[0].cb(-1, 0, sources[0].cb_data);
331  } else {
332  /* Real sources, use g_poll() main loop. */
333  sr_session_run_poll();
334  }
335 
336  return SR_OK;
337 }
338 
339 /**
340  * Halt the current session.
341  *
342  * This requests the current session be stopped as soon as possible, for
343  * example on receiving an SR_DF_END packet.
344  *
345  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
346  */
348 {
349  if (!session) {
350  sr_err("session: %s: session was NULL", __func__);
351  return SR_ERR_BUG;
352  }
353 
354  sr_info("session: halting");
355  session->running = FALSE;
356 
357  return SR_OK;
358 }
359 
360 /**
361  * Stop the current session.
362  *
363  * The current session is stopped immediately, with all acquisition sessions
364  * being stopped and hardware drivers cleaned up.
365  *
366  * @return SR_OK upon success, SR_ERR_BUG if no session exists.
367  */
369 {
370  struct sr_dev *dev;
371  GSList *l;
372 
373  if (!session) {
374  sr_err("session: %s: session was NULL", __func__);
375  return SR_ERR_BUG;
376  }
377 
378  sr_info("session: stopping");
379  session->running = FALSE;
380 
381  for (l = session->devs; l; l = l->next) {
382  dev = l->data;
383  /* Check for dev != NULL. */
384  if (dev->driver) {
385  if (dev->driver->dev_acquisition_stop)
386  dev->driver->dev_acquisition_stop(dev->driver_index, dev);
387  if (dev->driver->cleanup)
388  dev->driver->cleanup();
389  }
390  }
391 
392  return SR_OK;
393 }
394 
395 /**
396  * Debug helper.
397  *
398  * @param packet The packet to show debugging information for.
399  */
400 static void datafeed_dump(struct sr_datafeed_packet *packet)
401 {
402  struct sr_datafeed_logic *logic;
403 
404  switch (packet->type) {
405  case SR_DF_HEADER:
406  sr_dbg("bus: received SR_DF_HEADER");
407  break;
408  case SR_DF_TRIGGER:
409  sr_dbg("bus: received SR_DF_TRIGGER");
410  break;
411  case SR_DF_LOGIC:
412  logic = packet->payload;
413  /* TODO: Check for logic != NULL. */
414  sr_dbg("bus: received SR_DF_LOGIC %" PRIu64 " bytes", logic->length);
415  break;
416  case SR_DF_END:
417  sr_dbg("bus: received SR_DF_END");
418  break;
419  default:
420  sr_dbg("bus: received unknown packet type %d", packet->type);
421  break;
422  }
423 }
424 
425 /**
426  * Send a packet to whatever is listening on the datafeed bus.
427  *
428  * Hardware drivers use this to send a data packet to the frontend.
429  *
430  * @param dev TODO.
431  * @param packet The datafeed packet to send to the session bus.
432  *
433  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
434  */
436  struct sr_datafeed_packet *packet)
437 {
438  GSList *l;
440 
441  if (!dev) {
442  sr_err("session: %s: dev was NULL", __func__);
443  return SR_ERR_ARG;
444  }
445 
446  if (!packet) {
447  sr_err("session: %s: packet was NULL", __func__);
448  return SR_ERR_ARG;
449  }
450 
451  for (l = session->datafeed_callbacks; l; l = l->next) {
453  datafeed_dump(packet);
454  cb = l->data;
455  /* TODO: Check for cb != NULL. */
456  cb(dev, packet);
457  }
458 
459  return SR_OK;
460 }
461 
462 /**
463  * TODO.
464  *
465  * TODO: More error checks etc.
466  *
467  * @param fd TODO.
468  * @param events TODO.
469  * @param timeout TODO.
470  * @param cb Callback function to add. Must not be NULL.
471  * @param cb_data Data for the callback function. Can be NULL.
472  *
473  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments, or
474  * SR_ERR_MALLOC upon memory allocation errors.
475  */
476 SR_API int sr_session_source_add(int fd, int events, int timeout,
477  sr_receive_data_callback_t cb, void *cb_data)
478 {
479  struct source *new_sources, *s;
480 
481  if (!cb) {
482  sr_err("session: %s: cb was NULL", __func__);
483  return SR_ERR_ARG;
484  }
485 
486  /* Note: cb_data can be NULL, that's not a bug. */
487 
488  new_sources = g_try_malloc0(sizeof(struct source) * (num_sources + 1));
489  if (!new_sources) {
490  sr_err("session: %s: new_sources malloc failed", __func__);
491  return SR_ERR_MALLOC;
492  }
493 
494  if (sources) {
495  memcpy(new_sources, sources,
496  sizeof(struct source) * num_sources);
497  g_free(sources);
498  }
499 
500  s = &new_sources[num_sources++];
501  s->fd = fd;
502  s->events = events;
503  s->timeout = timeout;
504  s->cb = cb;
505  s->cb_data = cb_data;
506  sources = new_sources;
507 
508  if (timeout != source_timeout && timeout > 0
509  && (source_timeout == -1 || timeout < source_timeout))
510  source_timeout = timeout;
511 
512  return SR_OK;
513 }
514 
515 /**
516  * Remove the source belonging to the specified file descriptor.
517  *
518  * TODO: More error checks.
519  *
520  * @param fd TODO.
521  *
522  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments, or
523  * SR_ERR_MALLOC upon memory allocation errors, SR_ERR_BUG upon
524  * internal errors.
525  */
527 {
528  struct source *new_sources;
529  int old, new;
530 
531  if (!sources) {
532  sr_err("session: %s: sources was NULL", __func__);
533  return SR_ERR_BUG;
534  }
535 
536  /* TODO: Check if 'fd' valid. */
537 
538  new_sources = g_try_malloc0(sizeof(struct source) * num_sources);
539  if (!new_sources) {
540  sr_err("session: %s: new_sources malloc failed", __func__);
541  return SR_ERR_MALLOC;
542  }
543 
544  for (old = 0, new = 0; old < num_sources; old++) {
545  if (sources[old].fd != fd)
546  memcpy(&new_sources[new++], &sources[old],
547  sizeof(struct source));
548  }
549 
550  if (old != new) {
551  g_free(sources);
552  sources = new_sources;
553  num_sources--;
554  } else {
555  /* Target fd was not found. */
556  g_free(new_sources);
557  }
558 
559  return SR_OK;
560 }