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