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         "sync_volume=<syncronize sw and hw voluchanges in IO-thread?>");
  50
  51 struct device {
  52     char *path;
  53     pa_bool_t need_verify;
  54     char *card_name;
  55     char *args;
  56     uint32_t module;
  57     pa_ratelimit ratelimit;
  58 };
  59
  60 struct userdata {
  61     pa_core *core;
  62     pa_hashmap *devices;
  63
  64     pa_bool_t use_tsched:1;
  65     pa_bool_t ignore_dB:1;
  66     pa_bool_t sync_volume:1;
  67
  68     struct udev* udev;
  69     struct udev_monitor *monitor;
  70     pa_io_event *udev_io;
  71
  72     int inotify_fd;
  73     pa_io_event *inotify_io;
  74 };
  75
  76 static const char* const valid_modargs[] = {
  77     "tsched",
  78     "ignore_dB",
  79     "sync_volume",
  80     NULL
  81 };
  82
  83 static int setup_inotify(struct userdata *u);
  84
  85 static void device_free(struct device *d) {
  86     pa_assert(d);
  87
  88     pa_xfree(d->path);
  89     pa_xfree(d->card_name);
  90     pa_xfree(d->args);
  91     pa_xfree(d);
  92 }
  93
  94 static const char *path_get_card_id(const char *path) {
  95     const char *e;
  96
  97     if (!path)
  98         return NULL;
  99
 100     if (!(e = strrchr(path, '/')))
 101         return NULL;
 102
 103     if (!pa_startswith(e, "/card"))
 104         return NULL;
 105
 106     return e + 5;
 107 }
 108
 109 static char *card_get_sysattr(const char *card_idx, const char *name) {
 110     struct udev *udev;
 111     struct udev_device *card = NULL;
 112     char *t, *r = NULL;
 113     const char *v;
 114
 115     pa_assert(card_idx);
 116     pa_assert(name);
 117
 118     if (!(udev = udev_new())) {
 119         pa_log_error("Failed to allocate udev context.");
 120         goto finish;
 121     }
 122
 123     t = pa_sprintf_malloc("%s/class/sound/card%s", udev_get_sys_path(udev), card_idx);
 124     card = udev_device_new_from_syspath(udev, t);
 125     pa_xfree(t);
 126
 127     if (!card) {
 128         pa_log_error("Failed to get card object.");
 129         goto finish;
 130     }
 131
 132     if ((v = udev_device_get_sysattr_value(card, name)) && *v)
 133         r = pa_xstrdup(v);
 134
 135 finish:
 136
 137     if (card)
 138         udev_device_unref(card);
 139
 140     if (udev)
 141         udev_unref(udev);
 142
 143     return r;
 144 }
 145
 146 static pa_bool_t pcm_is_modem(const char *card_idx, const char *pcm) {
 147     char *sysfs_path, *pcm_class;
 148     pa_bool_t is_modem;
 149
 150     pa_assert(card_idx);
 151     pa_assert(pcm);
 152
 153     /* Check /sys/class/sound/card.../pcmC...../pcm_class. An HDA
 154      * modem can be used simultaneously with generic
 155      * playback/record. */
 156
 157     sysfs_path = pa_sprintf_malloc("pcmC%sD%s/pcm_class", card_idx, pcm);
 158     pcm_class = card_get_sysattr(card_idx, sysfs_path);
 159     is_modem = pcm_class && pa_streq(pcm_class, "modem");
 160     pa_xfree(pcm_class);
 161     pa_xfree(sysfs_path);
 162
 163     return is_modem;
 164 }
 165
 166 static pa_bool_t is_card_busy(const char *id) {
 167     char *card_path = NULL, *pcm_path = NULL, *sub_status = NULL;
 168     DIR *card_dir = NULL, *pcm_dir = NULL;
 169     FILE *status_file = NULL;
 170     size_t len;
 171     struct dirent *space = NULL, *de;
 172     pa_bool_t busy = FALSE;
 173     int r;
 174
 175     pa_assert(id);
 176
 177     /* This simply uses /proc/asound/card.../pcm.../sub.../status to
 178      * check whether there is still a process using this audio device. */
 179
 180     card_path = pa_sprintf_malloc("/proc/asound/card%s", id);
 181
 182     if (!(card_dir = opendir(card_path))) {
 183         pa_log_warn("Failed to open %s: %s", card_path, pa_cstrerror(errno));
 184         goto fail;
 185     }
 186
 187     len = offsetof(struct dirent, d_name) + fpathconf(dirfd(card_dir), _PC_NAME_MAX) + 1;
 188     space = pa_xmalloc(len);
 189
 190     for (;;) {
 191         de = NULL;
 192
 193         if ((r = readdir_r(card_dir, space, &de)) != 0) {
 194             pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
 195             goto fail;
 196         }
 197
 198         if (!de)
 199             break;
 200
 201         if (!pa_startswith(de->d_name, "pcm"))
 202             continue;
 203
 204         if (pcm_is_modem(id, de->d_name + 3))
 205             continue;
 206
 207         pa_xfree(pcm_path);
 208         pcm_path = pa_sprintf_malloc("%s/%s", card_path, de->d_name);
 209
 210         if (pcm_dir)
 211             closedir(pcm_dir);
 212
 213         if (!(pcm_dir = opendir(pcm_path))) {
 214             pa_log_warn("Failed to open %s: %s", pcm_path, pa_cstrerror(errno));
 215             continue;
 216         }
 217
 218         for (;;) {
 219             char line[32];
 220
 221             if ((r = readdir_r(pcm_dir, space, &de)) != 0) {
 222                 pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
 223                 goto fail;
 224             }
 225
 226             if (!de)
 227                 break;
 228
 229             if (!pa_startswith(de->d_name, "sub"))
 230                 continue;
 231
 232             pa_xfree(sub_status);
 233             sub_status = pa_sprintf_malloc("%s/%s/status", pcm_path, de->d_name);
 234
 235             if (status_file)
 236                 fclose(status_file);
 237
 238             if (!(status_file = pa_fopen_cloexec(sub_status, "r"))) {
 239                 pa_log_warn("Failed to open %s: %s", sub_status, pa_cstrerror(errno));
 240                 continue;
 241             }
 242
 243             if (!(fgets(line, sizeof(line)-1, status_file))) {
 244                 pa_log_warn("Failed to read from %s: %s", sub_status, pa_cstrerror(errno));
 245                 continue;
 246             }
 247
 248             if (!pa_streq(line, "closed\n")) {
 249                 busy = TRUE;
 250                 break;
 251             }
 252         }
 253     }
 254
 255 fail:
 256
 257     pa_xfree(card_path);
 258     pa_xfree(pcm_path);
 259     pa_xfree(sub_status);
 260     pa_xfree(space);
 261
 262     if (card_dir)
 263         closedir(card_dir);
 264
 265     if (pcm_dir)
 266         closedir(pcm_dir);
 267
 268     if (status_file)
 269         fclose(status_file);
 270
 271     return busy;
 272 }
 273
 274 static void verify_access(struct userdata *u, struct device *d) {
 275     char *cd;
 276     pa_card *card;
 277     pa_bool_t accessible;
 278
 279     pa_assert(u);
 280     pa_assert(d);
 281
 282     cd = pa_sprintf_malloc("%s/snd/controlC%s", udev_get_dev_path(u->udev), path_get_card_id(d->path));
 283     accessible = access(cd, R_OK|W_OK) >= 0;
 284     pa_log_debug("%s is accessible: %s", cd, pa_yes_no(accessible));
 285
 286     pa_xfree(cd);
 287
 288     if (d->module == PA_INVALID_INDEX) {
 289
 290         /* If we are not loaded, try to load */
 291
 292         if (accessible) {
 293             pa_module *m;
 294             pa_bool_t busy;
 295
 296             /* Check if any of the PCM devices that belong to this
 297              * card are currently busy. If they are, don't try to load
 298              * right now, to make sure the probing phase can
 299              * successfully complete. When the current user of the
 300              * device closes it we will get another notification via
 301              * inotify and can then recheck. */
 302
 303             busy = is_card_busy(path_get_card_id(d->path));
 304             pa_log_debug("%s is busy: %s", d->path, pa_yes_no(busy));
 305
 306             if (!busy) {
 307
 308                 /* So, why do we rate limit here? It's certainly ugly,
 309                  * but there seems to be no other way. Problem is
 310                  * this: if we are unable to configure/probe an audio
 311                  * device after opening it we will close it again and
 312                  * the module initialization will fail. This will then
 313                  * cause an inotify event on the device node which
 314                  * will be forwarded to us. We then try to reopen the
 315                  * audio device again, practically entering a busy
 316                  * loop.
 317                  *
 318                  * A clean fix would be if we would be able to ignore
 319                  * our own inotify close events. However, inotify
 320                  * lacks such functionality. Also, during probing of
 321                  * the device we cannot really distuingish between
 322                  * other processes causing EBUSY or ourselves, which
 323                  * means we have no way to figure out if the probing
 324                  * during opening was canceled by a "try again"
 325                  * failure or a "fatal" failure. */
 326
 327                 if (pa_ratelimit_test(&d->ratelimit, PA_LOG_DEBUG)) {
 328                     pa_log_debug("Loading module-alsa-card with arguments '%s'", d->args);
 329                     m = pa_module_load(u->core, "module-alsa-card", d->args);
 330
 331                     if (m) {
 332                         d->module = m->index;
 333                         pa_log_info("Card %s (%s) module loaded.", d->path, d->card_name);
 334                     } else
 335                         pa_log_info("Card %s (%s) failed to load module.", d->path, d->card_name);
 336                 } else
 337                     pa_log_warn("Tried to configure %s (%s) more often than %u times in %llus",
 338                                 d->path,
 339                                 d->card_name,
 340                                 d->ratelimit.burst,
 341                                 (long long unsigned) (d->ratelimit.interval / PA_USEC_PER_SEC));
 342             }
 343         }
 344
 345     } else {
 346
 347         /* If we are already loaded update suspend status with
 348          * accessible boolean */
 349
 350         if ((card = pa_namereg_get(u->core, d->card_name, PA_NAMEREG_CARD)))
 351             pa_card_suspend(card, !accessible, PA_SUSPEND_SESSION);
 352     }
 353 }
 354
 355 static void card_changed(struct userdata *u, struct udev_device *dev) {
 356     struct device *d;
 357     const char *path;
 358     const char *t;
 359     char *n;
 360
 361     pa_assert(u);
 362     pa_assert(dev);
 363
 364     /* Maybe /dev/snd is now available? */
 365     setup_inotify(u);
 366
 367     path = udev_device_get_devpath(dev);
 368
 369     if ((d = pa_hashmap_get(u->devices, path))) {
 370         verify_access(u, d);
 371         return;
 372     }
 373
 374     d = pa_xnew0(struct device, 1);
 375     d->path = pa_xstrdup(path);
 376     d->module = PA_INVALID_INDEX;
 377     PA_INIT_RATELIMIT(d->ratelimit, 10*PA_USEC_PER_SEC, 5);
 378
 379     if (!(t = udev_device_get_property_value(dev, "PULSE_NAME")))
 380         if (!(t = udev_device_get_property_value(dev, "ID_ID")))
 381             if (!(t = udev_device_get_property_value(dev, "ID_PATH")))
 382                 t = path_get_card_id(path);
 383
 384     n = pa_namereg_make_valid_name(t);
 385     d->card_name = pa_sprintf_malloc("alsa_card.%s", n);
 386     d->args = pa_sprintf_malloc("device_id=\"%s\" "
 387                                 "name=\"%s\" "
 388                                 "card_name=\"%s\" "
 389                                 "namereg_fail=false "
 390                                 "tsched=%s "
 391                                 "ignore_dB=%s "
 392                                 "sync_volume=%s "
 393                                 "card_properties=\"module-udev-detect.discovered=1\"",
 394                                 path_get_card_id(path),
 395                                 n,
 396                                 d->card_name,
 397                                 pa_yes_no(u->use_tsched),
 398                                 pa_yes_no(u->ignore_dB),
 399                                 pa_yes_no(u->sync_volume));
 400     pa_xfree(n);
 401
 402     pa_hashmap_put(u->devices, d->path, d);
 403
 404     verify_access(u, d);
 405 }
 406
 407 static void remove_card(struct userdata *u, struct udev_device *dev) {
 408     struct device *d;
 409
 410     pa_assert(u);
 411     pa_assert(dev);
 412
 413     if (!(d = pa_hashmap_remove(u->devices, udev_device_get_devpath(dev))))
 414         return;
 415
 416     pa_log_info("Card %s removed.", d->path);
 417
 418     if (d->module != PA_INVALID_INDEX)
 419         pa_module_unload_request_by_index(u->core, d->module, TRUE);
 420
 421     device_free(d);
 422 }
 423
 424 static void process_device(struct userdata *u, struct udev_device *dev) {
 425     const char *action, *ff;
 426
 427     pa_assert(u);
 428     pa_assert(dev);
 429
 430     if (udev_device_get_property_value(dev, "PULSE_IGNORE")) {
 431         pa_log_debug("Ignoring %s, because marked so.", udev_device_get_devpath(dev));
 432         return;
 433     }
 434
 435     if ((ff = udev_device_get_property_value(dev, "SOUND_CLASS")) &&
 436         pa_streq(ff, "modem")) {
 437         pa_log_debug("Ignoring %s, because it is a modem.", udev_device_get_devpath(dev));
 438         return;
 439     }
 440
 441     action = udev_device_get_action(dev);
 442
 443     if (action && pa_streq(action, "remove"))
 444         remove_card(u, dev);
 445     else if ((!action || pa_streq(action, "change")) && udev_device_get_property_value(dev, "SOUND_INITIALIZED"))
 446         card_changed(u, dev);
 447
 448     /* For an explanation why we don't look for 'add' events here
 449      * have a look into /lib/udev/rules.d/78-sound-card.rules! */
 450 }
 451
 452 static void process_path(struct userdata *u, const char *path) {
 453     struct udev_device *dev;
 454
 455     if (!path_get_card_id(path))
 456         return;
 457
 458     if (!(dev = udev_device_new_from_syspath(u->udev, path))) {
 459         pa_log("Failed to get udev device object from udev.");
 460         return;
 461     }
 462
 463     process_device(u, dev);
 464     udev_device_unref(dev);
 465 }
 466
 467 static void monitor_cb(
 468         pa_mainloop_api*a,
 469         pa_io_event* e,
 470         int fd,
 471         pa_io_event_flags_t events,
 472         void *userdata) {
 473
 474     struct userdata *u = userdata;
 475     struct udev_device *dev;
 476
 477     pa_assert(a);
 478
 479     if (!(dev = udev_monitor_receive_device(u->monitor))) {
 480         pa_log("Failed to get udev device object from monitor.");
 481         goto fail;
 482     }
 483
 484     if (!path_get_card_id(udev_device_get_devpath(dev))) {
 485         udev_device_unref(dev);
 486         return;
 487     }
 488
 489     process_device(u, dev);
 490     udev_device_unref(dev);
 491     return;
 492
 493 fail:
 494     a->io_free(u->udev_io);
 495     u->udev_io = NULL;
 496 }
 497
 498 static pa_bool_t pcm_node_belongs_to_device(
 499         struct device *d,
 500         const char *node) {
 501
 502     char *cd;
 503     pa_bool_t b;
 504
 505     cd = pa_sprintf_malloc("pcmC%sD", path_get_card_id(d->path));
 506     b = pa_startswith(node, cd);
 507     pa_xfree(cd);
 508
 509     return b;
 510 }
 511
 512 static pa_bool_t control_node_belongs_to_device(
 513         struct device *d,
 514         const char *node) {
 515
 516     char *cd;
 517     pa_bool_t b;
 518
 519     cd = pa_sprintf_malloc("controlC%s", path_get_card_id(d->path));
 520     b = pa_streq(node, cd);
 521     pa_xfree(cd);
 522
 523     return b;
 524 }
 525
 526 static void inotify_cb(
 527         pa_mainloop_api*a,
 528         pa_io_event* e,
 529         int fd,
 530         pa_io_event_flags_t events,
 531         void *userdata) {
 532
 533     struct {
 534         struct inotify_event e;
 535         char name[NAME_MAX];
 536     } buf;
 537     struct userdata *u = userdata;
 538     static int type = 0;
 539     pa_bool_t deleted = FALSE;
 540     struct device *d;
 541     void *state;
 542
 543     for (;;) {
 544         ssize_t r;
 545         struct inotify_event *event;
 546
 547         pa_zero(buf);
 548         if ((r = pa_read(fd, &buf, sizeof(buf), &type)) <= 0) {
 549
 550             if (r < 0 && errno == EAGAIN)
 551                 break;
 552
 553             pa_log("read() from inotify failed: %s", r < 0 ? pa_cstrerror(errno) : "EOF");
 554             goto fail;
 555         }
 556
 557         event = &buf.e;
 558         while (r > 0) {
 559             size_t len;
 560
 561             if ((size_t) r < sizeof(struct inotify_event)) {
 562                 pa_log("read() too short.");
 563                 goto fail;
 564             }
 565
 566             len = sizeof(struct inotify_event) + event->len;
 567
 568             if ((size_t) r < len) {
 569                 pa_log("Payload missing.");
 570                 goto fail;
 571             }
 572
 573             /* From udev we get the guarantee that the control
 574              * device's ACL is changed last. To avoid races when ACLs
 575              * are changed we hence watch only the control device */
 576             if (((event->mask & IN_ATTRIB) && pa_startswith(event->name, "controlC")))
 577                 PA_HASHMAP_FOREACH(d, u->devices, state)
 578                     if (control_node_belongs_to_device(d, event->name))
 579                         d->need_verify = TRUE;
 580
 581             /* ALSA doesn't really give us any guarantee on the closing
 582              * order, so let's simply hope */
 583             if (((event->mask & IN_CLOSE_WRITE) && pa_startswith(event->name, "pcmC")))
 584                 PA_HASHMAP_FOREACH(d, u->devices, state)
 585                     if (pcm_node_belongs_to_device(d, event->name))
 586                         d->need_verify = TRUE;
 587
 588             /* /dev/snd/ might have been removed */
 589             if ((event->mask & (IN_DELETE_SELF|IN_MOVE_SELF)))
 590                 deleted = TRUE;
 591
 592             event = (struct inotify_event*) ((uint8_t*) event + len);
 593             r -= len;
 594         }
 595     }
 596
 597     PA_HASHMAP_FOREACH(d, u->devices, state)
 598         if (d->need_verify) {
 599             d->need_verify = FALSE;
 600             verify_access(u, d);
 601         }
 602
 603     if (!deleted)
 604         return;
 605
 606 fail:
 607     if (u->inotify_io) {
 608         a->io_free(u->inotify_io);
 609         u->inotify_io = NULL;
 610     }
 611
 612     if (u->inotify_fd >= 0) {
 613         pa_close(u->inotify_fd);
 614         u->inotify_fd = -1;
 615     }
 616 }
 617
 618 static int setup_inotify(struct userdata *u) {
 619     char *dev_snd;
 620     int r;
 621
 622     if (u->inotify_fd >= 0)
 623         return 0;
 624
 625     if ((u->inotify_fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
 626         pa_log("inotify_init1() failed: %s", pa_cstrerror(errno));
 627         return -1;
 628     }
 629
 630     dev_snd = pa_sprintf_malloc("%s/snd", udev_get_dev_path(u->udev));
 631     r = inotify_add_watch(u->inotify_fd, dev_snd, IN_ATTRIB|IN_CLOSE_WRITE|IN_DELETE_SELF|IN_MOVE_SELF);
 632     pa_xfree(dev_snd);
 633
 634     if (r < 0) {
 635         int saved_errno = errno;
 636
 637         pa_close(u->inotify_fd);
 638         u->inotify_fd = -1;
 639
 640         if (saved_errno == ENOENT) {
 641             pa_log_debug("/dev/snd/ is apparently not existing yet, retrying to create inotify watch later.");
 642             return 0;
 643         }
 644
 645         if (saved_errno == ENOSPC) {
 646             pa_log("You apparently ran out of inotify watches, probably because Tracker/Beagle took them all away. "
 647                    "I wished people would do their homework first and fix inotify before using it for watching whole "
 648                    "directory trees which is something the current inotify is certainly not useful for. "
 649                    "Please make sure to drop the Tracker/Beagle guys a line complaining about their broken use of inotify.");
 650             return 0;
 651         }
 652
 653         pa_log("inotify_add_watch() failed: %s", pa_cstrerror(saved_errno));
 654         return -1;
 655     }
 656
 657     pa_assert_se(u->inotify_io = u->core->mainloop->io_new(u->core->mainloop, u->inotify_fd, PA_IO_EVENT_INPUT, inotify_cb, u));
 658
 659     return 0;
 660 }
 661
 662 int pa__init(pa_module *m) {
 663     struct userdata *u = NULL;
 664     pa_modargs *ma;
 665     struct udev_enumerate *enumerate = NULL;
 666     struct udev_list_entry *item = NULL, *first = NULL;
 667     int fd;
 668     pa_bool_t use_tsched = TRUE, ignore_dB = FALSE, sync_volume = m->core->sync_volume;
 669
 670
 671     pa_assert(m);
 672
 673     if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
 674         pa_log("Failed to parse module arguments");
 675         goto fail;
 676     }
 677
 678     m->userdata = u = pa_xnew0(struct userdata, 1);
 679     u->core = m->core;
 680     u->devices = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func);
 681     u->inotify_fd = -1;
 682
 683     if (pa_modargs_get_value_boolean(ma, "tsched", &use_tsched) < 0) {
 684         pa_log("Failed to parse tsched= argument.");
 685         goto fail;
 686     }
 687     u->use_tsched = use_tsched;
 688
 689     if (pa_modargs_get_value_boolean(ma, "ignore_dB", &ignore_dB) < 0) {
 690         pa_log("Failed to parse ignore_dB= argument.");
 691         goto fail;
 692     }
 693     u->ignore_dB = ignore_dB;
 694
 695     if (pa_modargs_get_value_boolean(ma, "sync_volume", &sync_volume) < 0) {
 696         pa_log("Failed to parse sync_volume= argument.");
 697         goto fail;
 698     }
 699     u->sync_volume = sync_volume;
 700
 701     if (!(u->udev = udev_new())) {
 702         pa_log("Failed to initialize udev library.");
 703         goto fail;
 704     }
 705
 706     if (setup_inotify(u) < 0)
 707         goto fail;
 708
 709     if (!(u->monitor = udev_monitor_new_from_netlink(u->udev, "udev"))) {
 710         pa_log("Failed to initialize monitor.");
 711         goto fail;
 712     }
 713
 714     if (udev_monitor_filter_add_match_subsystem_devtype(u->monitor, "sound", NULL) < 0) {
 715         pa_log("Failed to subscribe to sound devices.");
 716         goto fail;
 717     }
 718
 719     errno = 0;
 720     if (udev_monitor_enable_receiving(u->monitor) < 0) {
 721         pa_log("Failed to enable monitor: %s", pa_cstrerror(errno));
 722         if (errno == EPERM)
 723             pa_log_info("Most likely your kernel is simply too old and "
 724                         "allows only priviliged processes to listen to device events. "
 725                         "Please upgrade your kernel to at least 2.6.30.");
 726         goto fail;
 727     }
 728
 729     if ((fd = udev_monitor_get_fd(u->monitor)) < 0) {
 730         pa_log("Failed to get udev monitor fd.");
 731         goto fail;
 732     }
 733
 734     pa_assert_se(u->udev_io = u->core->mainloop->io_new(u->core->mainloop, fd, PA_IO_EVENT_INPUT, monitor_cb, u));
 735
 736     if (!(enumerate = udev_enumerate_new(u->udev))) {
 737         pa_log("Failed to initialize udev enumerator.");
 738         goto fail;
 739     }
 740
 741     if (udev_enumerate_add_match_subsystem(enumerate, "sound") < 0) {
 742         pa_log("Failed to match to subsystem.");
 743         goto fail;
 744     }
 745
 746     if (udev_enumerate_scan_devices(enumerate) < 0) {
 747         pa_log("Failed to scan for devices.");
 748         goto fail;
 749     }
 750
 751     first = udev_enumerate_get_list_entry(enumerate);
 752     udev_list_entry_foreach(item, first)
 753         process_path(u, udev_list_entry_get_name(item));
 754
 755     udev_enumerate_unref(enumerate);
 756
 757     pa_log_info("Found %u cards.", pa_hashmap_size(u->devices));
 758
 759     pa_modargs_free(ma);
 760
 761     return 0;
 762
 763 fail:
 764
 765     if (enumerate)
 766         udev_enumerate_unref(enumerate);
 767
 768     if (ma)
 769         pa_modargs_free(ma);
 770
 771     pa__done(m);
 772
 773     return -1;
 774 }
 775
 776 void pa__done(pa_module *m) {
 777     struct userdata *u;
 778
 779     pa_assert(m);
 780
 781     if (!(u = m->userdata))
 782         return;
 783
 784     if (u->udev_io)
 785         m->core->mainloop->io_free(u->udev_io);
 786
 787     if (u->monitor)
 788         udev_monitor_unref(u->monitor);
 789
 790     if (u->udev)
 791         udev_unref(u->udev);
 792
 793     if (u->inotify_io)
 794         m->core->mainloop->io_free(u->inotify_io);
 795
 796     if (u->inotify_fd >= 0)
 797         pa_close(u->inotify_fd);
 798
 799     if (u->devices) {
 800         struct device *d;
 801
 802         while ((d = pa_hashmap_steal_first(u->devices)))
 803             device_free(d);
 804
 805         pa_hashmap_free(u->devices, NULL, NULL);
 806     }
 807
 808     pa_xfree(u);
 809 }