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[pulseaudio] / src / modules / module-udev-detect.c
1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2009 Lennart Poettering
5
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
10
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with PulseAudio; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
19 USA.
20 ***/
21
22 #ifdef HAVE_CONFIG_H
23 #include <config.h>
24 #endif
25
26 #include <errno.h>
27 #include <limits.h>
28 #include <dirent.h>
29 #include <sys/inotify.h>
30 #include <libudev.h>
31
32 #include <pulse/timeval.h>
33
34 #include <pulsecore/modargs.h>
35 #include <pulsecore/core-error.h>
36 #include <pulsecore/core-util.h>
37 #include <pulsecore/namereg.h>
38 #include <pulsecore/ratelimit.h>
39
40 #include "module-udev-detect-symdef.h"
41
42 PA_MODULE_AUTHOR("Lennart Poettering");
43 PA_MODULE_DESCRIPTION("Detect available audio hardware and load matching drivers");
44 PA_MODULE_VERSION(PACKAGE_VERSION);
45 PA_MODULE_LOAD_ONCE(TRUE);
46 PA_MODULE_USAGE(
47 "tsched=<enable system timer based scheduling mode?> "
48 "ignore_dB=<ignore dB information from the device?>");
49
50 struct device {
51 char *path;
52 pa_bool_t need_verify;
53 char *card_name;
54 char *args;
55 uint32_t module;
56 pa_ratelimit ratelimit;
57 };
58
59 struct userdata {
60 pa_core *core;
61 pa_hashmap *devices;
62
63 pa_bool_t use_tsched:1;
64 pa_bool_t ignore_dB:1;
65
66 struct udev* udev;
67 struct udev_monitor *monitor;
68 pa_io_event *udev_io;
69
70 int inotify_fd;
71 pa_io_event *inotify_io;
72 };
73
74 static const char* const valid_modargs[] = {
75 "tsched",
76 "ignore_dB",
77 NULL
78 };
79
80 static int setup_inotify(struct userdata *u);
81
82 static void device_free(struct device *d) {
83 pa_assert(d);
84
85 pa_xfree(d->path);
86 pa_xfree(d->card_name);
87 pa_xfree(d->args);
88 pa_xfree(d);
89 }
90
91 static const char *path_get_card_id(const char *path) {
92 const char *e;
93
94 if (!path)
95 return NULL;
96
97 if (!(e = strrchr(path, '/')))
98 return NULL;
99
100 if (!pa_startswith(e, "/card"))
101 return NULL;
102
103 return e + 5;
104 }
105
106 static pa_bool_t is_card_busy(const char *id) {
107 char *card_path = NULL, *pcm_path = NULL, *sub_status = NULL;
108 DIR *card_dir = NULL, *pcm_dir = NULL;
109 FILE *status_file = NULL;
110 size_t len;
111 struct dirent *space = NULL, *de;
112 pa_bool_t busy = FALSE;
113 int r;
114
115 pa_assert(id);
116
117 /* This simply uses /proc/asound/card.../pcm.../sub.../status to
118 * check whether there is still a process using this audio device. */
119
120 card_path = pa_sprintf_malloc("/proc/asound/card%s", id);
121
122 if (!(card_dir = opendir(card_path))) {
123 pa_log_warn("Failed to open %s: %s", card_path, pa_cstrerror(errno));
124 goto fail;
125 }
126
127 len = offsetof(struct dirent, d_name) + fpathconf(dirfd(card_dir), _PC_NAME_MAX) + 1;
128 space = pa_xmalloc(len);
129
130 for (;;) {
131 de = NULL;
132
133 if ((r = readdir_r(card_dir, space, &de)) != 0) {
134 pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
135 goto fail;
136 }
137
138 if (!de)
139 break;
140
141 if (!pa_startswith(de->d_name, "pcm"))
142 continue;
143
144 pa_xfree(pcm_path);
145 pcm_path = pa_sprintf_malloc("%s/%s", card_path, de->d_name);
146
147 if (pcm_dir)
148 closedir(pcm_dir);
149
150 if (!(pcm_dir = opendir(pcm_path))) {
151 pa_log_warn("Failed to open %s: %s", pcm_path, pa_cstrerror(errno));
152 continue;
153 }
154
155 for (;;) {
156 char line[32];
157
158 if ((r = readdir_r(pcm_dir, space, &de)) != 0) {
159 pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
160 goto fail;
161 }
162
163 if (!de)
164 break;
165
166 if (!pa_startswith(de->d_name, "sub"))
167 continue;
168
169 pa_xfree(sub_status);
170 sub_status = pa_sprintf_malloc("%s/%s/status", pcm_path, de->d_name);
171
172 if (status_file)
173 fclose(status_file);
174
175 if (!(status_file = pa_fopen_cloexec(sub_status, "r"))) {
176 pa_log_warn("Failed to open %s: %s", sub_status, pa_cstrerror(errno));
177 continue;
178 }
179
180 if (!(fgets(line, sizeof(line)-1, status_file))) {
181 pa_log_warn("Failed to read from %s: %s", sub_status, pa_cstrerror(errno));
182 continue;
183 }
184
185 if (!pa_streq(line, "closed\n")) {
186 busy = TRUE;
187 break;
188 }
189 }
190 }
191
192 fail:
193
194 pa_xfree(card_path);
195 pa_xfree(pcm_path);
196 pa_xfree(sub_status);
197 pa_xfree(space);
198
199 if (card_dir)
200 closedir(card_dir);
201
202 if (pcm_dir)
203 closedir(pcm_dir);
204
205 if (status_file)
206 fclose(status_file);
207
208 return busy;
209 }
210
211 static void verify_access(struct userdata *u, struct device *d) {
212 char *cd;
213 pa_card *card;
214 pa_bool_t accessible;
215
216 pa_assert(u);
217 pa_assert(d);
218
219 cd = pa_sprintf_malloc("%s/snd/controlC%s", udev_get_dev_path(u->udev), path_get_card_id(d->path));
220 accessible = access(cd, R_OK|W_OK) >= 0;
221 pa_log_debug("%s is accessible: %s", cd, pa_yes_no(accessible));
222
223 pa_xfree(cd);
224
225 if (d->module == PA_INVALID_INDEX) {
226
227 /* If we are not loaded, try to load */
228
229 if (accessible) {
230 pa_module *m;
231 pa_bool_t busy;
232
233 /* Check if any of the PCM devices that belong to this
234 * card are currently busy. If they are, don't try to load
235 * right now, to make sure the probing phase can
236 * successfully complete. When the current user of the
237 * device closes it we will get another notification via
238 * inotify and can then recheck. */
239
240 busy = is_card_busy(path_get_card_id(d->path));
241 pa_log_debug("%s is busy: %s", d->path, pa_yes_no(busy));
242
243 if (!busy) {
244
245 /* So, why do we rate limit here? It's certainly ugly,
246 * but there seems to be no other way. Problem is
247 * this: if we are unable to configure/probe an audio
248 * device after opening it we will close it again and
249 * the module initialization will fail. This will then
250 * cause an inotify event on the device node which
251 * will be forwarded to us. We then try to reopen the
252 * audio device again, practically entering a busy
253 * loop.
254 *
255 * A clean fix would be if we would be able to ignore
256 * our own inotify close events. However, inotify
257 * lacks such functionality. Also, during probing of
258 * the device we cannot really distuingish between
259 * other processes causing EBUSY or ourselves, which
260 * means we have no way to figure out if the probing
261 * during opening was canceled by a "try again"
262 * failure or a "fatal" failure. */
263
264 if (pa_ratelimit_test(&d->ratelimit)) {
265 pa_log_debug("Loading module-alsa-card with arguments '%s'", d->args);
266 m = pa_module_load(u->core, "module-alsa-card", d->args);
267
268 if (m) {
269 d->module = m->index;
270 pa_log_info("Card %s (%s) module loaded.", d->path, d->card_name);
271 } else
272 pa_log_info("Card %s (%s) failed to load module.", d->path, d->card_name);
273 } else
274 pa_log_warn("Tried to configure %s (%s) more often than %u times in %llus",
275 d->path,
276 d->card_name,
277 d->ratelimit.burst,
278 (long long unsigned) (d->ratelimit.interval / PA_USEC_PER_SEC));
279 }
280 }
281
282 } else {
283
284 /* If we are already loaded update suspend status with
285 * accessible boolean */
286
287 if ((card = pa_namereg_get(u->core, d->card_name, PA_NAMEREG_CARD)))
288 pa_card_suspend(card, !accessible, PA_SUSPEND_SESSION);
289 }
290 }
291
292 static void card_changed(struct userdata *u, struct udev_device *dev) {
293 struct device *d;
294 const char *path;
295 const char *t;
296 char *n;
297
298 pa_assert(u);
299 pa_assert(dev);
300
301 /* Maybe /dev/snd is now available? */
302 setup_inotify(u);
303
304 path = udev_device_get_devpath(dev);
305
306 if ((d = pa_hashmap_get(u->devices, path))) {
307 verify_access(u, d);
308 return;
309 }
310
311 d = pa_xnew0(struct device, 1);
312 d->path = pa_xstrdup(path);
313 d->module = PA_INVALID_INDEX;
314 PA_INIT_RATELIMIT(d->ratelimit, 10*PA_USEC_PER_SEC, 5);
315
316 if (!(t = udev_device_get_property_value(dev, "PULSE_NAME")))
317 if (!(t = udev_device_get_property_value(dev, "ID_ID")))
318 if (!(t = udev_device_get_property_value(dev, "ID_PATH")))
319 t = path_get_card_id(path);
320
321 n = pa_namereg_make_valid_name(t);
322 d->card_name = pa_sprintf_malloc("alsa_card.%s", n);
323 d->args = pa_sprintf_malloc("device_id=\"%s\" "
324 "name=\"%s\" "
325 "card_name=\"%s\" "
326 "tsched=%s "
327 "ignore_dB=%s "
328 "card_properties=\"module-udev-detect.discovered=1\"",
329 path_get_card_id(path),
330 n,
331 d->card_name,
332 pa_yes_no(u->use_tsched),
333 pa_yes_no(u->ignore_dB));
334 pa_xfree(n);
335
336 pa_hashmap_put(u->devices, d->path, d);
337
338 verify_access(u, d);
339 }
340
341 static void remove_card(struct userdata *u, struct udev_device *dev) {
342 struct device *d;
343
344 pa_assert(u);
345 pa_assert(dev);
346
347 if (!(d = pa_hashmap_remove(u->devices, udev_device_get_devpath(dev))))
348 return;
349
350 pa_log_info("Card %s removed.", d->path);
351
352 if (d->module != PA_INVALID_INDEX)
353 pa_module_unload_request_by_index(u->core, d->module, TRUE);
354
355 device_free(d);
356 }
357
358 static void process_device(struct userdata *u, struct udev_device *dev) {
359 const char *action, *ff;
360
361 pa_assert(u);
362 pa_assert(dev);
363
364 if (udev_device_get_property_value(dev, "PULSE_IGNORE")) {
365 pa_log_debug("Ignoring %s, because marked so.", udev_device_get_devpath(dev));
366 return;
367 }
368
369 if ((ff = udev_device_get_property_value(dev, "SOUND_FORM_FACTOR")) &&
370 pa_streq(ff, "modem")) {
371 pa_log_debug("Ignoring %s, because it is a modem.", udev_device_get_devpath(dev));
372 return;
373 }
374
375 action = udev_device_get_action(dev);
376
377 if (action && pa_streq(action, "remove"))
378 remove_card(u, dev);
379 else if ((!action || pa_streq(action, "change")) &&
380 udev_device_get_property_value(dev, "SOUND_INITIALIZED"))
381 card_changed(u, dev);
382
383 /* For an explanation why we don't look for 'add' events here
384 * have a look into /lib/udev/rules.d/78-sound-card.rules! */
385 }
386
387 static void process_path(struct userdata *u, const char *path) {
388 struct udev_device *dev;
389
390 if (!path_get_card_id(path))
391 return;
392
393 if (!(dev = udev_device_new_from_syspath(u->udev, path))) {
394 pa_log("Failed to get udev device object from udev.");
395 return;
396 }
397
398 process_device(u, dev);
399 udev_device_unref(dev);
400 }
401
402 static void monitor_cb(
403 pa_mainloop_api*a,
404 pa_io_event* e,
405 int fd,
406 pa_io_event_flags_t events,
407 void *userdata) {
408
409 struct userdata *u = userdata;
410 struct udev_device *dev;
411
412 pa_assert(a);
413
414 if (!(dev = udev_monitor_receive_device(u->monitor))) {
415 pa_log("Failed to get udev device object from monitor.");
416 goto fail;
417 }
418
419 if (!path_get_card_id(udev_device_get_devpath(dev)))
420 return;
421
422 process_device(u, dev);
423 udev_device_unref(dev);
424 return;
425
426 fail:
427 a->io_free(u->udev_io);
428 u->udev_io = NULL;
429 }
430
431 static pa_bool_t pcm_node_belongs_to_device(
432 struct device *d,
433 const char *node) {
434
435 char *cd;
436 pa_bool_t b;
437
438 cd = pa_sprintf_malloc("pcmC%sD", path_get_card_id(d->path));
439 b = pa_startswith(node, cd);
440 pa_xfree(cd);
441
442 return b;
443 }
444
445 static pa_bool_t control_node_belongs_to_device(
446 struct device *d,
447 const char *node) {
448
449 char *cd;
450 pa_bool_t b;
451
452 cd = pa_sprintf_malloc("controlC%s", path_get_card_id(d->path));
453 b = pa_streq(node, cd);
454 pa_xfree(cd);
455
456 return b;
457 }
458
459 static void inotify_cb(
460 pa_mainloop_api*a,
461 pa_io_event* e,
462 int fd,
463 pa_io_event_flags_t events,
464 void *userdata) {
465
466 struct {
467 struct inotify_event e;
468 char name[NAME_MAX];
469 } buf;
470 struct userdata *u = userdata;
471 static int type = 0;
472 pa_bool_t deleted = FALSE;
473 struct device *d;
474 void *state;
475
476 for (;;) {
477 ssize_t r;
478 struct inotify_event *event;
479
480 pa_zero(buf);
481 if ((r = pa_read(fd, &buf, sizeof(buf), &type)) <= 0) {
482
483 if (r < 0 && errno == EAGAIN)
484 break;
485
486 pa_log("read() from inotify failed: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
487 goto fail;
488 }
489
490 event = &buf.e;
491 while (r > 0) {
492 size_t len;
493
494 if ((size_t) r < sizeof(struct inotify_event)) {
495 pa_log("read() too short.");
496 goto fail;
497 }
498
499 len = sizeof(struct inotify_event) + event->len;
500
501 if ((size_t) r < len) {
502 pa_log("Payload missing.");
503 goto fail;
504 }
505
506 /* From udev we get the guarantee that the control
507 * device's ACL is changed last. To avoid races when ACLs
508 * are changed we hence watch only the control device */
509 if (((event->mask & IN_ATTRIB) && pa_startswith(event->name, "controlC")))
510 PA_HASHMAP_FOREACH(d, u->devices, state)
511 if (control_node_belongs_to_device(d, event->name))
512 d->need_verify = TRUE;
513
514 /* ALSA doesn't really give us any guarantee on the closing
515 * order, so let's simply hope */
516 if (((event->mask & IN_CLOSE_WRITE) && pa_startswith(event->name, "pcmC")))
517 PA_HASHMAP_FOREACH(d, u->devices, state)
518 if (pcm_node_belongs_to_device(d, event->name))
519 d->need_verify = TRUE;
520
521 /* /dev/snd/ might have been removed */
522 if ((event->mask & (IN_DELETE_SELF|IN_MOVE_SELF)))
523 deleted = TRUE;
524
525 event = (struct inotify_event*) ((uint8_t*) event + len);
526 r -= len;
527 }
528 }
529
530 PA_HASHMAP_FOREACH(d, u->devices, state)
531 if (d->need_verify) {
532 d->need_verify = FALSE;
533 verify_access(u, d);
534 }
535
536 if (!deleted)
537 return;
538
539 fail:
540 if (u->inotify_io) {
541 a->io_free(u->inotify_io);
542 u->inotify_io = NULL;
543 }
544
545 if (u->inotify_fd >= 0) {
546 pa_close(u->inotify_fd);
547 u->inotify_fd = -1;
548 }
549 }
550
551 static int setup_inotify(struct userdata *u) {
552 char *dev_snd;
553 int r;
554
555 if (u->inotify_fd >= 0)
556 return 0;
557
558 if ((u->inotify_fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
559 pa_log("inotify_init1() failed: %s", pa_cstrerror(errno));
560 return -1;
561 }
562
563 dev_snd = pa_sprintf_malloc("%s/snd", udev_get_dev_path(u->udev));
564 r = inotify_add_watch(u->inotify_fd, dev_snd, IN_ATTRIB|IN_CLOSE_WRITE|IN_DELETE_SELF|IN_MOVE_SELF);
565 pa_xfree(dev_snd);
566
567 if (r < 0) {
568 int saved_errno = errno;
569
570 pa_close(u->inotify_fd);
571 u->inotify_fd = -1;
572
573 if (saved_errno == ENOENT) {
574 pa_log_debug("/dev/snd/ is apparently not existing yet, retrying to create inotify watch later.");
575 return 0;
576 }
577
578 if (saved_errno == ENOSPC) {
579 pa_log("You apparently ran out of inotify watches, probably because Tracker/Beagle took them all away. "
580 "I wished people would do their homework first and fix inotify before using it for watching whole "
581 "directory trees which is something the current inotify is certainly not useful for. "
582 "Please make sure to drop the Tracker/Beagle guys a line complaining about their broken use of inotify.");
583 return 0;
584 }
585
586 pa_log("inotify_add_watch() failed: %s", pa_cstrerror(saved_errno));
587 return -1;
588 }
589
590 pa_assert_se(u->inotify_io = u->core->mainloop->io_new(u->core->mainloop, u->inotify_fd, PA_IO_EVENT_INPUT, inotify_cb, u));
591
592 return 0;
593 }
594
595 int pa__init(pa_module *m) {
596 struct userdata *u = NULL;
597 pa_modargs *ma;
598 struct udev_enumerate *enumerate = NULL;
599 struct udev_list_entry *item = NULL, *first = NULL;
600 int fd;
601 pa_bool_t use_tsched = TRUE, ignore_dB = FALSE;
602
603 pa_assert(m);
604
605 if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
606 pa_log("Failed to parse module arguments");
607 goto fail;
608 }
609
610 m->userdata = u = pa_xnew0(struct userdata, 1);
611 u->core = m->core;
612 u->devices = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func);
613 u->inotify_fd = -1;
614
615 if (pa_modargs_get_value_boolean(ma, "tsched", &use_tsched) < 0) {
616 pa_log("Failed to parse tsched= argument.");
617 goto fail;
618 }
619 u->use_tsched = use_tsched;
620
621 if (pa_modargs_get_value_boolean(ma, "ignore_dB", &ignore_dB) < 0) {
622 pa_log("Failed to parse ignore_dB= argument.");
623 goto fail;
624 }
625 u->ignore_dB = ignore_dB;
626
627 if (!(u->udev = udev_new())) {
628 pa_log("Failed to initialize udev library.");
629 goto fail;
630 }
631
632 if (setup_inotify(u) < 0)
633 goto fail;
634
635 if (!(u->monitor = udev_monitor_new_from_netlink(u->udev, "udev"))) {
636 pa_log("Failed to initialize monitor.");
637 goto fail;
638 }
639
640 errno = 0;
641 if (udev_monitor_enable_receiving(u->monitor) < 0) {
642 pa_log("Failed to enable monitor: %s", pa_cstrerror(errno));
643 if (errno == EPERM)
644 pa_log_info("Most likely your kernel is simply too old and "
645 "allows only priviliged processes to listen to device events. "
646 "Please upgrade your kernel to at least 2.6.30.");
647 goto fail;
648 }
649
650 if ((fd = udev_monitor_get_fd(u->monitor)) < 0) {
651 pa_log("Failed to get udev monitor fd.");
652 goto fail;
653 }
654
655 pa_assert_se(u->udev_io = u->core->mainloop->io_new(u->core->mainloop, fd, PA_IO_EVENT_INPUT, monitor_cb, u));
656
657 if (!(enumerate = udev_enumerate_new(u->udev))) {
658 pa_log("Failed to initialize udev enumerator.");
659 goto fail;
660 }
661
662 if (udev_enumerate_add_match_subsystem(enumerate, "sound") < 0) {
663 pa_log("Failed to match to subsystem.");
664 goto fail;
665 }
666
667 if (udev_enumerate_scan_devices(enumerate) < 0) {
668 pa_log("Failed to scan for devices.");
669 goto fail;
670 }
671
672 first = udev_enumerate_get_list_entry(enumerate);
673 udev_list_entry_foreach(item, first)
674 process_path(u, udev_list_entry_get_name(item));
675
676 udev_enumerate_unref(enumerate);
677
678 pa_log_info("Found %u cards.", pa_hashmap_size(u->devices));
679
680 pa_modargs_free(ma);
681
682 return 0;
683
684 fail:
685
686 if (enumerate)
687 udev_enumerate_unref(enumerate);
688
689 if (ma)
690 pa_modargs_free(ma);
691
692 pa__done(m);
693
694 return -1;
695 }
696
697 void pa__done(pa_module *m) {
698 struct userdata *u;
699
700 pa_assert(m);
701
702 if (!(u = m->userdata))
703 return;
704
705 if (u->udev_io)
706 m->core->mainloop->io_free(u->udev_io);
707
708 if (u->monitor)
709 udev_monitor_unref(u->monitor);
710
711 if (u->udev)
712 udev_unref(u->udev);
713
714 if (u->inotify_io)
715 m->core->mainloop->io_free(u->inotify_io);
716
717 if (u->inotify_fd >= 0)
718 pa_close(u->inotify_fd);
719
720 if (u->devices) {
721 struct device *d;
722
723 while ((d = pa_hashmap_steal_first(u->devices)))
724 device_free(d);
725
726 pa_hashmap_free(u->devices, NULL, NULL);
727 }
728
729 pa_xfree(u);
730 }