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 program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program 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 Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 #include <errno.h>
  28 #include <search.h>
  29 #include <poll.h>
  30 #include <sys/stat.h>
  31 #include <fcntl.h>
  32
  33 #include <libudev.h>
  34
  35 #include <vlc_common.h>
  36 #include <vlc_services_discovery.h>
  37 #include <vlc_plugin.h>
  38 #ifdef HAVE_ALSA
  39 # include <vlc_modules.h>
  40 #endif
  41 #include <vlc_url.h>
  42
  43 static int OpenV4L (vlc_object_t *);
  44 #ifdef HAVE_ALSA
  45 static int OpenALSA (vlc_object_t *);
  46 #endif
  47 static int OpenDisc (vlc_object_t *);
  48 static void Close (vlc_object_t *);
  49 static int vlc_sd_probe_Open (vlc_object_t *);
  50
  51 /*
  52  * Module descriptor
  53  */
  54 vlc_module_begin ()
  55     set_shortname (N_("Video capture"))
  56     set_description (N_("Video capture (Video4Linux)"))
  57     set_category (CAT_PLAYLIST)
  58     set_subcategory (SUBCAT_PLAYLIST_SD)
  59     set_capability ("services_discovery", 0)
  60     set_callbacks (OpenV4L, Close)
  61     add_shortcut ("v4l", "video")
  62 #ifdef HAVE_ALSA
  63     add_submodule ()
  64     set_shortname (N_("Audio capture"))
  65     set_description (N_("Audio capture (ALSA)"))
  66     set_category (CAT_PLAYLIST)
  67     set_subcategory (SUBCAT_PLAYLIST_SD)
  68     set_capability ("services_discovery", 0)
  69     set_callbacks (OpenALSA, Close)
  70     add_shortcut ("alsa", "audio")
  71 #endif
  72     add_submodule ()
  73     set_shortname (N_("Discs"))
  74     set_description (N_("Discs"))
  75     set_category (CAT_PLAYLIST)
  76     set_subcategory (SUBCAT_PLAYLIST_SD)
  77     set_capability ("services_discovery", 0)
  78     set_callbacks (OpenDisc, Close)
  79     add_shortcut ("disc")
  80
  81     VLC_SD_PROBE_SUBMODULE
  82
  83 vlc_module_end ()
  84
  85 static int vlc_sd_probe_Open (vlc_object_t *obj)
  86 {
  87     vlc_probe_t *probe = (vlc_probe_t *)obj;
  88
  89     struct udev *udev = udev_new ();
  90     if (udev == NULL)
  91         return VLC_PROBE_CONTINUE;
  92
  93     struct udev_monitor *mon = udev_monitor_new_from_netlink (udev, "udev");
  94     if (mon != NULL)
  95     {
  96         vlc_sd_probe_Add (probe, "v4l{longname=\"Video capture\"}",
  97                           N_("Video capture"), SD_CAT_DEVICES);
  98 #ifdef HAVE_ALSA
  99         if (!module_exists ("pulselist"))
 100             vlc_sd_probe_Add (probe, "alsa{longname=\"Audio capture\"}",
 101                               N_("Audio capture"), SD_CAT_DEVICES);
 102 #endif
 103         vlc_sd_probe_Add (probe, "disc{longname=\"Discs\"}", N_("Discs"),
 104                           SD_CAT_DEVICES);
 105         udev_monitor_unref (mon);
 106     }
 107     udev_unref (udev);
 108     return VLC_PROBE_CONTINUE;
 109 }
 110
 111 struct device
 112 {
 113     dev_t devnum; /* must be first */
 114     input_item_t *item;
 115     services_discovery_t *sd;
 116 };
 117
 118 struct subsys
 119 {
 120     const char *name;
 121     char * (*get_mrl) (struct udev_device *dev);
 122     char * (*get_name) (struct udev_device *dev);
 123     int item_type;
 124 };
 125
 126 struct services_discovery_sys_t
 127 {
 128     const struct subsys *subsys;
 129     struct udev_monitor *monitor;
 130     vlc_thread_t         thread;
 131     void                *root;
 132 };
 133
 134 /**
 135  * Compares two devices (to support binary search).
 136  */
 137 static int cmpdev (const void *a, const void *b)
 138 {
 139     const dev_t *da = a, *db = b;
 140
 141     if (*da > *db)
 142         return +1;
 143     if (*da < *db)
 144         return -1;
 145     return 0;
 146 }
 147
 148 static void DestroyDevice (void *data)
 149 {
 150     struct device *d = data;
 151
 152     if (d->sd)
 153         services_discovery_RemoveItem (d->sd, d->item);
 154     vlc_gc_decref (d->item);
 155     free (d);
 156 }
 157
 158 static char *decode_property (struct udev_device *, const char *);
 159
 160 /**
 161  * Adds a udev device.
 162  */
 163 static int AddDevice (services_discovery_t *sd, struct udev_device *dev)
 164 {
 165     services_discovery_sys_t *p_sys = sd->p_sys;
 166
 167     char *mrl = p_sys->subsys->get_mrl (dev);
 168     if (mrl == NULL)
 169         return 0; /* don't know if it was an error... */
 170     char *name = p_sys->subsys->get_name (dev);
 171     input_item_t *item = input_item_NewWithType (mrl, name ? name : mrl,
 172                                                  0, NULL, 0, -1,
 173                                                  p_sys->subsys->item_type);
 174     msg_Dbg (sd, "adding %s (%s)", mrl, name);
 175     free (name);
 176     free (mrl);
 177     if (item == NULL)
 178         return -1;
 179
 180     struct device *d = malloc (sizeof (*d));
 181     if (d == NULL)
 182     {
 183         vlc_gc_decref (item);
 184         return -1;
 185     }
 186     d->devnum = udev_device_get_devnum (dev);
 187     d->item = item;
 188     d->sd = NULL;
 189
 190     struct device **dp = tsearch (d, &p_sys->root, cmpdev);
 191     if (dp == NULL) /* Out-of-memory */
 192     {
 193         DestroyDevice (d);
 194         return -1;
 195     }
 196     if (*dp != d) /* Overwrite existing device */
 197     {
 198         DestroyDevice (*dp);
 199         *dp = d;
 200     }
 201
 202     services_discovery_AddItem (sd, item, NULL);
 203     d->sd = sd;
 204     return 0;
 205 }
 206
 207 /**
 208  * Removes a udev device (if present).
 209  */
 210 static void RemoveDevice (services_discovery_t *sd, struct udev_device *dev)
 211 {
 212     services_discovery_sys_t *p_sys = sd->p_sys;
 213
 214     dev_t num = udev_device_get_devnum (dev);
 215     struct device **dp = tfind (&(dev_t){ num }, &p_sys->root, cmpdev);
 216     if (dp == NULL)
 217         return;
 218
 219     struct device *d = *dp;
 220     tdelete (d, &p_sys->root, cmpdev);
 221     DestroyDevice (d);
 222 }
 223
 224 static void *Run (void *);
 225
 226 /**
 227  * Probes and initializes.
 228  */
 229 static int Open (vlc_object_t *obj, const struct subsys *subsys)
 230 {
 231     services_discovery_t *sd = (services_discovery_t *)obj;
 232     services_discovery_sys_t *p_sys = malloc (sizeof (*p_sys));
 233
 234     if (p_sys == NULL)
 235         return VLC_ENOMEM;
 236     sd->p_sys = p_sys;
 237     p_sys->subsys = subsys;
 238     p_sys->root = NULL;
 239
 240     struct udev_monitor *mon = NULL;
 241     struct udev *udev = udev_new ();
 242     if (udev == NULL)
 243         goto error;
 244
 245     mon = udev_monitor_new_from_netlink (udev, "udev");
 246     if (mon == NULL
 247      || udev_monitor_filter_add_match_subsystem_devtype (mon, subsys->name,
 248                                                          NULL))
 249         goto error;
 250     p_sys->monitor = mon;
 251
 252     /* Enumerate existing devices */
 253     struct udev_enumerate *devenum = udev_enumerate_new (udev);
 254     if (devenum == NULL)
 255         goto error;
 256     if (udev_enumerate_add_match_subsystem (devenum, subsys->name))
 257     {
 258         udev_enumerate_unref (devenum);
 259         goto error;
 260     }
 261
 262     udev_monitor_enable_receiving (mon);
 263     /* Note that we enumerate _after_ monitoring is enabled so that we do not
 264      * loose device events occuring while we are enumerating. We could still
 265      * loose events if the Netlink socket receive buffer overflows. */
 266     udev_enumerate_scan_devices (devenum);
 267     struct udev_list_entry *devlist = udev_enumerate_get_list_entry (devenum);
 268     struct udev_list_entry *deventry;
 269     udev_list_entry_foreach (deventry, devlist)
 270     {
 271         const char *path = udev_list_entry_get_name (deventry);
 272         struct udev_device *dev = udev_device_new_from_syspath (udev, path);
 273         AddDevice (sd, dev);
 274         udev_device_unref (dev);
 275     }
 276     udev_enumerate_unref (devenum);
 277
 278     if (vlc_clone (&p_sys->thread, Run, sd, VLC_THREAD_PRIORITY_LOW))
 279     {   /* Fallback without thread */
 280         udev_monitor_unref (mon);
 281         udev_unref (udev);
 282         p_sys->monitor = NULL;
 283     }
 284     return VLC_SUCCESS;
 285
 286 error:
 287     if (mon != NULL)
 288         udev_monitor_unref (mon);
 289     if (udev != NULL)
 290         udev_unref (udev);
 291     free (p_sys);
 292     return VLC_EGENERIC;
 293 }
 294
 295 /**
 296  * Releases resources
 297  */
 298 static void Close (vlc_object_t *obj)
 299 {
 300     services_discovery_t *sd = (services_discovery_t *)obj;
 301     services_discovery_sys_t *p_sys = sd->p_sys;
 302
 303     if (p_sys->monitor != NULL)
 304     {
 305         struct udev *udev = udev_monitor_get_udev (p_sys->monitor);
 306
 307         vlc_cancel (p_sys->thread);
 308         vlc_join (p_sys->thread, NULL);
 309         udev_monitor_unref (p_sys->monitor);
 310         udev_unref (udev);
 311     }
 312
 313     tdestroy (p_sys->root, DestroyDevice);
 314     free (p_sys);
 315 }
 316
 317 static void *Run (void *data)
 318 {
 319     services_discovery_t *sd = data;
 320     services_discovery_sys_t *p_sys = sd->p_sys;
 321     struct udev_monitor *mon = p_sys->monitor;
 322
 323     int fd = udev_monitor_get_fd (mon);
 324     struct pollfd ufd = { .fd = fd, .events = POLLIN, };
 325
 326     for (;;)
 327     {
 328         while (poll (&ufd, 1, -1) == -1)
 329             if (errno != EINTR)
 330                 break;
 331
 332         int canc = vlc_savecancel ();
 333         struct udev_device *dev = udev_monitor_receive_device (mon);
 334         if (dev == NULL)
 335             continue;
 336
 337         const char *action = udev_device_get_action (dev);
 338         if (!strcmp (action, "add"))
 339             AddDevice (sd, dev);
 340         else if (!strcmp (action, "remove"))
 341             RemoveDevice (sd, dev);
 342         else if (!strcmp (action, "change"))
 343         {
 344             RemoveDevice (sd, dev);
 345             AddDevice (sd, dev);
 346         }
 347         udev_device_unref (dev);
 348         vlc_restorecancel (canc);
 349     }
 350     return NULL;
 351 }
 352
 353 /**
 354  * Converts an hexadecimal digit to an integer.
 355  */
 356 static int hex (char c)
 357 {
 358     if (c >= '0' && c <= '9')
 359         return c - '0';
 360     if (c >= 'A' && c <= 'F')
 361         return c + 10 - 'A';
 362     if (c >= 'a' && c <= 'f')
 363         return c + 10 - 'a';
 364     return -1;
 365 }
 366
 367 /**
 368  * Decodes a udev hexadecimal-encoded property.
 369  */
 370 static char *decode (const char *enc)
 371 {
 372     char *ret = enc ? strdup (enc) : NULL;
 373     if (ret == NULL)
 374         return NULL;
 375
 376     char *out = ret;
 377     for (const char *in = ret; *in; out++)
 378     {
 379         int h1, h2;
 380
 381         if ((in[0] == '\\') && (in[1] == 'x')
 382          && ((h1 = hex (in[2])) != -1)
 383          && ((h2 = hex (in[3])) != -1))
 384         {
 385             *out = (h1 << 4) | h2;
 386             in += 4;
 387         }
 388         else
 389         {
 390             *out = *in;
 391             in++;
 392         }
 393     }
 394     *out = 0;
 395     return ret;
 396 }
 397
 398 static char *decode_property (struct udev_device *dev, const char *name)
 399 {
 400     return decode (udev_device_get_property_value (dev, name));
 401 }
 402
 403
 404 /*** Video4Linux support ***/
 405 static bool v4l_is_legacy (struct udev_device *dev)
 406 {
 407     const char *version;
 408
 409     version = udev_device_get_property_value (dev, "ID_V4L_VERSION");
 410     return (version != NULL) && !strcmp (version, "1");
 411 }
 412
 413 static bool v4l_can_capture (struct udev_device *dev)
 414 {
 415     const char *caps;
 416
 417     caps = udev_device_get_property_value (dev, "ID_V4L_CAPABILITIES");
 418     return (caps != NULL) && (strstr (caps, ":capture:") != NULL);
 419 }
 420
 421 static char *v4l_get_mrl (struct udev_device *dev)
 422 {
 423     /* Determine media location */
 424     if (v4l_is_legacy (dev) || !v4l_can_capture (dev))
 425         return NULL;
 426
 427     const char *node = udev_device_get_devnode (dev);
 428     char *mrl;
 429
 430     if (asprintf (&mrl, "v4l2://%s", node) == -1)
 431         mrl = NULL;
 432     return mrl;
 433 }
 434
 435 static char *v4l_get_name (struct udev_device *dev)
 436 {
 437     const char *prd = udev_device_get_property_value (dev, "ID_V4L_PRODUCT");
 438     return prd ? strdup (prd) : NULL;
 439 }
 440
 441 int OpenV4L (vlc_object_t *obj)
 442 {
 443     static const struct subsys subsys = {
 444         "video4linux", v4l_get_mrl, v4l_get_name, ITEM_TYPE_CARD,
 445     };
 446
 447     return Open (obj, &subsys);
 448 }
 449
 450
 451 #ifdef HAVE_ALSA
 452 /*** Advanced Linux Sound Architecture support ***/
 453 #include <alsa/asoundlib.h>
 454
 455 static int alsa_get_device (struct udev_device *dev, unsigned *restrict pcard,
 456                             unsigned *restrict pdevice)
 457 {
 458     const char *node = udev_device_get_devpath (dev);
 459     char type;
 460
 461     node = strrchr (node, '/');
 462     if (node == NULL)
 463         return -1;
 464     if (sscanf (node, "/pcmC%uD%u%c", pcard, pdevice, &type) < 3)
 465         return -1;
 466     if (type != 'c')
 467         return -1;
 468     return 0;
 469 }
 470
 471
 472 static char *alsa_get_mrl (struct udev_device *dev)
 473 {
 474     /* Determine media location */
 475     char *mrl;
 476     unsigned card, device;
 477
 478     if (alsa_get_device (dev, &card, &device))
 479         return NULL;
 480
 481     if (asprintf (&mrl, "alsa://plughw:%u,%u", card, device) == -1)
 482         mrl = NULL;
 483     return mrl;
 484 }
 485
 486 static char *alsa_get_name (struct udev_device *dev)
 487 {
 488     char *name = NULL;
 489     unsigned card, device;
 490
 491     if (alsa_get_device (dev, &card, &device))
 492         return NULL;
 493
 494     char card_name[4 + 3 * sizeof (int)];
 495     snprintf (card_name, sizeof (card_name), "hw:%u", card);
 496
 497     snd_ctl_t *ctl;
 498     if (snd_ctl_open (&ctl, card_name, 0))
 499         return NULL;
 500
 501     snd_pcm_info_t *pcm_info;
 502     snd_pcm_info_alloca (&pcm_info);
 503     snd_pcm_info_set_device (pcm_info, device);
 504     snd_pcm_info_set_subdevice (pcm_info, 0);
 505     snd_pcm_info_set_stream (pcm_info, SND_PCM_STREAM_CAPTURE);
 506     if (snd_ctl_pcm_info (ctl, pcm_info))
 507         goto out;
 508
 509     name = strdup (snd_pcm_info_get_name (pcm_info));
 510 out:
 511     snd_ctl_close (ctl);
 512     return name;
 513 }
 514
 515 int OpenALSA (vlc_object_t *obj)
 516 {
 517     static const struct subsys subsys = {
 518         "sound", alsa_get_mrl, alsa_get_name, ITEM_TYPE_CARD,
 519     };
 520
 521     return Open (obj, &subsys);
 522 }
 523 #endif /* HAVE_ALSA */
 524
 525
 526 /*** Discs support ***/
 527 static char *disc_get_mrl (struct udev_device *dev)
 528 {
 529     const char *node = udev_device_get_devnode (dev);
 530     const char *val;
 531
 532     val = udev_device_get_property_value (dev, "ID_CDROM");
 533     if (val == NULL)
 534         return NULL; /* Ignore non-optical block devices */
 535
 536     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_STATE");
 537     if (val == NULL)
 538     {   /* Force probing of the disc in the drive if any. */
 539         int fd = open (node, O_RDONLY|O_CLOEXEC);
 540         if (fd != -1)
 541             close (fd);
 542         return NULL;
 543     }
 544     if (!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 = "bluray";
 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     return vlc_path2uri (node, scheme);
 571 }
 572
 573 static char *disc_get_name (struct udev_device *dev)
 574 {
 575     char *name = NULL;
 576     struct udev_list_entry *list, *entry;
 577
 578     list = udev_device_get_properties_list_entry (dev);
 579     if (unlikely(list == NULL))
 580         return NULL;
 581
 582     const char *cat = NULL;
 583     udev_list_entry_foreach (entry, list)
 584     {
 585         const char *name = udev_list_entry_get_name (entry);
 586
 587         if (strncmp (name, "ID_CDROM_MEDIA_", 15))
 588             continue;
 589         if (!atoi (udev_list_entry_get_value (entry)))
 590             continue;
 591         name += 15;
 592
 593         if (!strncmp (name, "CD", 2))
 594             cat = N_("CD");
 595         else if (!strncmp (name, "DVD", 3))
 596             cat = N_("DVD");
 597         else if (!strncmp (name, "BD", 2))
 598             cat = N_("Blu-ray");
 599         else if (!strncmp (name, "HDDVD", 5))
 600             cat = N_("HD DVD");
 601
 602         if (cat != NULL)
 603             break;
 604     }
 605
 606     if (cat == NULL)
 607         cat = N_("Unknown type");
 608
 609     char *label = decode_property (dev, "ID_FS_LABEL_ENC");
 610
 611     if (label)
 612         if (asprintf(&name, "%s (%s)", label, vlc_gettext(cat)) < 0)
 613             name = NULL;
 614     free(label);
 615
 616     return name;
 617 }
 618
 619 int OpenDisc (vlc_object_t *obj)
 620 {
 621     static const struct subsys subsys = {
 622         "block", disc_get_mrl, disc_get_name, ITEM_TYPE_DISC,
 623     };
 624
 625     return Open (obj, &subsys);
 626 }