modules/services_discovery/udev.c

   1 /**
   2  * @file udev.c
   3  * @brief List of multimedia devices for VLC media player
   4  */
   5 /*****************************************************************************
   6  * Copyright © 2009 Rémi Denis-Courmont
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  ****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 #include <libudev.h>
  28 #include <vlc_common.h>
  29 #include <vlc_services_discovery.h>
  30 #include <vlc_plugin.h>
  31 #include <vlc_url.h>
  32 #ifdef HAVE_SEARCH_H
  33 # include <search.h>
  34 #endif
  35 #include <poll.h>
  36 #include <errno.h>
  37
  38 static int OpenV4L (vlc_object_t *);
  39 #ifdef HAVE_ALSA
  40 static int OpenALSA (vlc_object_t *);
  41 #endif
  42 static int OpenDisc (vlc_object_t *);
  43 static void Close (vlc_object_t *);
  44 static int vlc_sd_probe_Open (vlc_object_t *);
  45
  46 /*
  47  * Module descriptor
  48  */
  49 vlc_module_begin ()
  50     set_shortname (N_("Video capture"))
  51     set_description (N_("Video capture (Video4Linux)"))
  52     set_category (CAT_PLAYLIST)
  53     set_subcategory (SUBCAT_PLAYLIST_SD)
  54     set_capability ("services_discovery", 0)
  55     set_callbacks (OpenV4L, Close)
  56     add_shortcut ("v4l")
  57 #ifdef HAVE_ALSA
  58     add_submodule ()
  59     set_shortname (N_("Audio capture"))
  60     set_description (N_("Audio capture (ALSA)"))
  61     set_category (CAT_PLAYLIST)
  62     set_subcategory (SUBCAT_PLAYLIST_SD)
  63     set_capability ("services_discovery", 0)
  64     set_callbacks (OpenALSA, Close)
  65     add_shortcut ("alsa")
  66 #endif
  67     add_submodule ()
  68     set_shortname (N_("Discs"))
  69     set_description (N_("Discs"))
  70     set_category (CAT_PLAYLIST)
  71     set_subcategory (SUBCAT_PLAYLIST_SD)
  72     set_capability ("services_discovery", 0)
  73     set_callbacks (OpenDisc, Close)
  74     add_shortcut ("disc")
  75
  76     VLC_SD_PROBE_SUBMODULE
  77
  78 vlc_module_end ()
  79
  80 static int vlc_sd_probe_Open (vlc_object_t *obj)
  81 {
  82     vlc_probe_t *probe = (vlc_probe_t *)obj;
  83
  84     struct udev *udev = udev_new ();
  85     if (udev == NULL)
  86         return VLC_PROBE_CONTINUE;
  87
  88     struct udev_monitor *mon = udev_monitor_new_from_netlink (udev, "udev");
  89     if (mon != NULL)
  90     {
  91         vlc_sd_probe_Add (probe, "v4l{longname=\"Video capture\"}",
  92                           N_("Video capture"), SD_CAT_DEVICES);
  93 #ifdef HAVE_ALSA
  94         vlc_sd_probe_Add (probe, "alsa{longname=\"Audio capture\"}",
  95                           N_("Audio capture"), SD_CAT_DEVICES);
  96 #endif
  97         vlc_sd_probe_Add (probe, "disc{longname=\"Discs\"}", N_("Discs"),
  98                           SD_CAT_DEVICES);
  99         udev_monitor_unref (mon);
 100     }
 101     udev_unref (udev);
 102     return VLC_PROBE_CONTINUE;
 103 }
 104
 105 struct device
 106 {
 107     dev_t devnum; /* must be first */
 108     input_item_t *item;
 109     services_discovery_t *sd;
 110 };
 111
 112 struct subsys
 113 {
 114     const char *name;
 115     char * (*get_mrl) (struct udev_device *dev);
 116     char * (*get_name) (struct udev_device *dev);
 117     char * (*get_cat) (struct udev_device *dev);
 118     int item_type;
 119 };
 120
 121 struct services_discovery_sys_t
 122 {
 123     const struct subsys *subsys;
 124     struct udev_monitor *monitor;
 125     vlc_thread_t         thread;
 126     void                *root;
 127 };
 128
 129 /**
 130  * Compares two devices (to support binary search).
 131  */
 132 static int cmpdev (const void *a, const void *b)
 133 {
 134     const dev_t *da = a, *db = b;
 135     dev_t delta = *da - *db;
 136
 137     if (sizeof (delta) > sizeof (int))
 138         return delta ? ((delta > 0) ? 1 : -1) : 0;
 139     return (signed)delta;
 140 }
 141
 142 static void DestroyDevice (void *data)
 143 {
 144     struct device *d = data;
 145
 146     if (d->sd)
 147         services_discovery_RemoveItem (d->sd, d->item);
 148     vlc_gc_decref (d->item);
 149     free (d);
 150 }
 151
 152 static char *decode_property (struct udev_device *, const char *);
 153
 154 /**
 155  * Adds a udev device.
 156  */
 157 static int AddDevice (services_discovery_t *sd, struct udev_device *dev)
 158 {
 159     services_discovery_sys_t *p_sys = sd->p_sys;
 160
 161     char *mrl = p_sys->subsys->get_mrl (dev);
 162     if (mrl == NULL)
 163         return 0; /* don't know if it was an error... */
 164     char *name = p_sys->subsys->get_name (dev);
 165     input_item_t *item = input_item_NewWithType (mrl, name ? name : mrl,
 166                                                  0, NULL, 0, -1,
 167                                                  p_sys->subsys->item_type);
 168     msg_Dbg (sd, "adding %s (%s)", mrl, name);
 169     free (name);
 170     free (mrl);
 171     if (item == NULL)
 172         return -1;
 173
 174     struct device *d = malloc (sizeof (*d));
 175     if (d == NULL)
 176     {
 177         vlc_gc_decref (item);
 178         return -1;
 179     }
 180     d->devnum = udev_device_get_devnum (dev);
 181     d->item = item;
 182     d->sd = NULL;
 183
 184     struct device **dp = tsearch (d, &p_sys->root, cmpdev);
 185     if (dp == NULL) /* Out-of-memory */
 186     {
 187         DestroyDevice (d);
 188         return -1;
 189     }
 190     if (*dp != d) /* Overwrite existing device */
 191     {
 192         DestroyDevice (*dp);
 193         *dp = d;
 194     }
 195
 196     name = p_sys->subsys->get_cat (dev);
 197     services_discovery_AddItem (sd, item, name ? name : "Generic");
 198     d->sd = sd;
 199     free (name);
 200     return 0;
 201 }
 202
 203 /**
 204  * Removes a udev device (if present).
 205  */
 206 static void RemoveDevice (services_discovery_t *sd, struct udev_device *dev)
 207 {
 208     services_discovery_sys_t *p_sys = sd->p_sys;
 209
 210     dev_t num = udev_device_get_devnum (dev);
 211     struct device **dp = tfind (&(dev_t){ num }, &p_sys->root, cmpdev);
 212     if (dp == NULL)
 213         return;
 214
 215     struct device *d = *dp;
 216     tdelete (d, &p_sys->root, cmpdev);
 217     DestroyDevice (d);
 218 }
 219
 220 static void *Run (void *);
 221
 222 /**
 223  * Probes and initializes.
 224  */
 225 static int Open (vlc_object_t *obj, const struct subsys *subsys)
 226 {
 227     services_discovery_t *sd = (services_discovery_t *)obj;
 228     services_discovery_sys_t *p_sys = malloc (sizeof (*p_sys));
 229
 230     if (p_sys == NULL)
 231         return VLC_ENOMEM;
 232     sd->p_sys = p_sys;
 233     p_sys->subsys = subsys;
 234     p_sys->root = NULL;
 235
 236     struct udev_monitor *mon = NULL;
 237     struct udev *udev = udev_new ();
 238     if (udev == NULL)
 239         goto error;
 240
 241     mon = udev_monitor_new_from_netlink (udev, "udev");
 242     if (mon == NULL
 243      || udev_monitor_filter_add_match_subsystem_devtype (mon, subsys->name,
 244                                                          NULL))
 245         goto error;
 246     p_sys->monitor = mon;
 247
 248     /* Enumerate existing devices */
 249     struct udev_enumerate *devenum = udev_enumerate_new (udev);
 250     if (devenum == NULL)
 251         goto error;
 252     if (udev_enumerate_add_match_subsystem (devenum, subsys->name))
 253     {
 254         udev_enumerate_unref (devenum);
 255         goto error;
 256     }
 257
 258     udev_monitor_enable_receiving (mon);
 259     /* Note that we enumerate _after_ monitoring is enabled so that we do not
 260      * loose device events occuring while we are enumerating. We could still
 261      * loose events if the Netlink socket receive buffer overflows. */
 262     udev_enumerate_scan_devices (devenum);
 263     struct udev_list_entry *devlist = udev_enumerate_get_list_entry (devenum);
 264     struct udev_list_entry *deventry;
 265     udev_list_entry_foreach (deventry, devlist)
 266     {
 267         const char *path = udev_list_entry_get_name (deventry);
 268         struct udev_device *dev = udev_device_new_from_syspath (udev, path);
 269         AddDevice (sd, dev);
 270         udev_device_unref (dev);
 271     }
 272     udev_enumerate_unref (devenum);
 273
 274     if (vlc_clone (&p_sys->thread, Run, sd, VLC_THREAD_PRIORITY_LOW))
 275     {   /* Fallback without thread */
 276         udev_monitor_unref (mon);
 277         udev_unref (udev);
 278         p_sys->monitor = NULL;
 279     }
 280     return VLC_SUCCESS;
 281
 282 error:
 283     if (mon != NULL)
 284         udev_monitor_unref (mon);
 285     if (udev != NULL)
 286         udev_unref (udev);
 287     free (p_sys);
 288     return VLC_EGENERIC;
 289 }
 290
 291 /**
 292  * Releases resources
 293  */
 294 static void Close (vlc_object_t *obj)
 295 {
 296     services_discovery_t *sd = (services_discovery_t *)obj;
 297     services_discovery_sys_t *p_sys = sd->p_sys;
 298
 299     if (p_sys->monitor != NULL)
 300     {
 301         struct udev *udev = udev_monitor_get_udev (p_sys->monitor);
 302
 303         vlc_cancel (p_sys->thread);
 304         vlc_join (p_sys->thread, NULL);
 305         udev_monitor_unref (p_sys->monitor);
 306         udev_unref (udev);
 307     }
 308
 309     tdestroy (p_sys->root, DestroyDevice);
 310     free (p_sys);
 311 }
 312
 313 static void *Run (void *data)
 314 {
 315     services_discovery_t *sd = data;
 316     services_discovery_sys_t *p_sys = sd->p_sys;
 317     struct udev_monitor *mon = p_sys->monitor;
 318
 319     int fd = udev_monitor_get_fd (mon);
 320     struct pollfd ufd = { .fd = fd, .events = POLLIN, };
 321
 322     for (;;)
 323     {
 324         while (poll (&ufd, 1, -1) == -1)
 325             if (errno != EINTR)
 326                 break;
 327
 328         int canc = vlc_savecancel ();
 329         struct udev_device *dev = udev_monitor_receive_device (mon);
 330         if (dev == NULL)
 331             continue;
 332
 333         const char *action = udev_device_get_action (dev);
 334         if (!strcmp (action, "add"))
 335             AddDevice (sd, dev);
 336         else if (!strcmp (action, "remove"))
 337             RemoveDevice (sd, dev);
 338         else if (!strcmp (action, "change"))
 339         {
 340             RemoveDevice (sd, dev);
 341             AddDevice (sd, dev);
 342         }
 343         udev_device_unref (dev);
 344         vlc_restorecancel (canc);
 345     }
 346     return NULL;
 347 }
 348
 349 /**
 350  * Converts an hexadecimal digit to an integer.
 351  */
 352 static int hex (char c)
 353 {
 354     if (c >= '0' && c <= '9')
 355         return c - '0';
 356     if (c >= 'A' && c <= 'F')
 357         return c + 10 - 'A';
 358     if (c >= 'a' && c <= 'f')
 359         return c + 10 - 'a';
 360     return -1;
 361 }
 362
 363 /**
 364  * Decodes a udev hexadecimal-encoded property.
 365  */
 366 static char *decode (const char *enc)
 367 {
 368     char *ret = enc ? strdup (enc) : NULL;
 369     if (ret == NULL)
 370         return NULL;
 371
 372     char *out = ret;
 373     for (const char *in = ret; *in; out++)
 374     {
 375         int h1, h2;
 376
 377         if ((in[0] == '\\') && (in[1] == 'x')
 378          && ((h1 = hex (in[2])) != -1)
 379          && ((h2 = hex (in[3])) != -1))
 380         {
 381             *out = (h1 << 4) | h2;
 382             in += 4;
 383         }
 384         else
 385         {
 386             *out = *in;
 387             in++;
 388         }
 389     }
 390     *out = 0;
 391     return ret;
 392 }
 393
 394 static char *decode_property (struct udev_device *dev, const char *name)
 395 {
 396     return decode (udev_device_get_property_value (dev, name));
 397 }
 398
 399
 400 /*** Video4Linux support ***/
 401 static bool is_v4l_legacy (struct udev_device *dev)
 402 {
 403     const char *version;
 404
 405     version = udev_device_get_property_value (dev, "ID_V4L_VERSION");
 406     return version && !strcmp (version, "1");
 407 }
 408
 409 static char *v4l_get_mrl (struct udev_device *dev)
 410 {
 411     /* Determine media location */
 412     if (is_v4l_legacy (dev))
 413         return NULL;
 414
 415     const char *node = udev_device_get_devnode (dev);
 416     char *mrl;
 417
 418     if (asprintf (&mrl, "v4l2://%s", node) == -1)
 419         mrl = NULL;
 420     return mrl;
 421 }
 422
 423 static char *v4l_get_name (struct udev_device *dev)
 424 {
 425     const char *prd = udev_device_get_property_value (dev, "ID_V4L_PRODUCT");
 426     return prd ? strdup (prd) : NULL;
 427 }
 428
 429 static char *v4l_get_cat (struct udev_device *dev)
 430 {
 431     return decode_property (dev, "ID_VENDOR_ENC");
 432 }
 433
 434 int OpenV4L (vlc_object_t *obj)
 435 {
 436     static const struct subsys subsys = {
 437         "video4linux", v4l_get_mrl, v4l_get_name, v4l_get_cat, ITEM_TYPE_CARD,
 438     };
 439
 440     return Open (obj, &subsys);
 441 }
 442
 443
 444 #ifdef HAVE_ALSA
 445 /*** Advanced Linux Sound Architecture support ***/
 446 #include <alsa/asoundlib.h>
 447
 448 static int alsa_get_device (struct udev_device *dev, unsigned *restrict pcard,
 449                             unsigned *restrict pdevice)
 450 {
 451     const char *node = udev_device_get_devpath (dev);
 452     char type;
 453
 454     node = strrchr (node, '/');
 455     if (node == NULL)
 456         return -1;
 457     if (sscanf (node, "/pcmC%uD%u%c", pcard, pdevice, &type) < 3)
 458         return -1;
 459     if (type != 'c')
 460         return -1;
 461     return 0;
 462 }
 463
 464
 465 static char *alsa_get_mrl (struct udev_device *dev)
 466 {
 467     /* Determine media location */
 468     char *mrl;
 469     unsigned card, device;
 470
 471     if (alsa_get_device (dev, &card, &device))
 472         return NULL;
 473
 474     if (asprintf (&mrl, "alsa://plughw:%u,%u", card, device) == -1)
 475         mrl = NULL;
 476     return mrl;
 477 }
 478
 479 static char *alsa_get_name (struct udev_device *dev)
 480 {
 481     char *name = NULL;
 482     unsigned card, device;
 483
 484     if (alsa_get_device (dev, &card, &device))
 485         return NULL;
 486
 487     char card_name[4 + 3 * sizeof (int)];
 488     snprintf (card_name, sizeof (card_name), "hw:%u", card);
 489
 490     snd_ctl_t *ctl;
 491     if (snd_ctl_open (&ctl, card_name, 0))
 492         return NULL;
 493
 494     snd_pcm_info_t *pcm_info;
 495     snd_pcm_info_alloca (&pcm_info);
 496     snd_pcm_info_set_device (pcm_info, device);
 497     snd_pcm_info_set_subdevice (pcm_info, 0);
 498     snd_pcm_info_set_stream (pcm_info, SND_PCM_STREAM_CAPTURE);
 499     if (snd_ctl_pcm_info (ctl, pcm_info))
 500         goto out;
 501
 502     name = strdup (snd_pcm_info_get_name (pcm_info));
 503 out:
 504     snd_ctl_close (ctl);
 505     return name;
 506 }
 507
 508 static char *alsa_get_cat (struct udev_device *dev)
 509 {
 510     const char *vnd;
 511
 512     dev = udev_device_get_parent (dev);
 513     if (dev == NULL)
 514         return NULL;
 515
 516     vnd = udev_device_get_property_value (dev, "ID_VENDOR_FROM_DATABASE");
 517     if (vnd == NULL)
 518         /* FIXME: USB may take time to settle... the parent device */
 519         vnd = udev_device_get_property_value (dev, "ID_BUS");
 520     return vnd ? strdup (vnd) : NULL;
 521 }
 522
 523 int OpenALSA (vlc_object_t *obj)
 524 {
 525     static const struct subsys subsys = {
 526         "sound", alsa_get_mrl, alsa_get_name, alsa_get_cat, ITEM_TYPE_CARD,
 527     };
 528
 529     return Open (obj, &subsys);
 530 }
 531 #endif /* HAVE_ALSA */
 532
 533
 534 /*** Discs support ***/
 535 static char *disc_get_mrl (struct udev_device *dev)
 536 {
 537     const char *val;
 538
 539     val = udev_device_get_property_value (dev, "ID_CDROM");
 540     if (val == NULL)
 541         return NULL; /* Ignore non-optical block devices */
 542
 543     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_STATE");
 544     if (val && !strcmp (val, "blank"))
 545         return NULL; /* ignore empty drives and virgin recordable discs */
 546
 547     const char *scheme = NULL;
 548     val = udev_device_get_property_value (dev,
 549                                           "ID_CDROM_MEDIA_TRACK_COUNT_AUDIO");
 550     if (val && atoi (val))
 551         scheme = "cdda"; /* Audio CD rather than file system */
 552     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_DVD");
 553     if (val && atoi (val))
 554         scheme = "dvd";
 555
 556     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_BD");
 557     if (val && atoi (val))
 558         scheme = "bd";
 559 #ifdef LOL
 560     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_HDDVD");
 561     if (val && atoi (val))
 562         scheme = "hddvd";
 563 #endif
 564
 565     /* We didn't get any property that could tell we have optical disc
 566        that we can play */
 567     if (scheme == NULL)
 568         return NULL;
 569
 570     val = udev_device_get_devnode (dev);
 571     return make_URI (val, scheme);
 572 }
 573
 574 static char *disc_get_name (struct udev_device *dev)
 575 {
 576     return decode_property (dev, "ID_FS_LABEL_ENC");
 577 }
 578
 579 static char *disc_get_cat (struct udev_device *dev)
 580 {
 581     struct udev_list_entry *list, *entry;
 582
 583     list = udev_device_get_properties_list_entry (dev);
 584     if (unlikely(list == NULL))
 585         return NULL;
 586
 587     const char *cat = NULL;
 588     udev_list_entry_foreach (entry, list)
 589     {
 590         const char *name = udev_list_entry_get_name (entry);
 591
 592         if (strncmp (name, "ID_CDROM_MEDIA_", 15))
 593             continue;
 594         if (!atoi (udev_list_entry_get_value (entry)))
 595             continue;
 596         name += 15;
 597
 598         if (!strncmp (name, "CD", 2))
 599             cat = N_("CD");
 600         else if (!strncmp (name, "DVD", 3))
 601             cat = N_("DVD");
 602         else if (!strncmp (name, "BD", 2))
 603             cat = N_("Blu-Ray");
 604         else if (!strncmp (name, "HDDVD", 5))
 605             cat = N_("HD DVD");
 606
 607         if (cat != NULL)
 608             break;
 609     }
 610
 611     if (cat == NULL)
 612         cat = N_("Unknown type");
 613     return strdup (vlc_gettext (cat));
 614 }
 615
 616 int OpenDisc (vlc_object_t *obj)
 617 {
 618     static const struct subsys subsys = {
 619         "block", disc_get_mrl, disc_get_name, disc_get_cat, ITEM_TYPE_DISC,
 620     };
 621
 622     return Open (obj, &subsys);
 623 }