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_fs.h>
  42 #include <vlc_url.h>
  43
  44 static int OpenV4L (vlc_object_t *);
  45 #ifdef HAVE_ALSA
  46 static int OpenALSA (vlc_object_t *);
  47 #endif
  48 static int OpenDisc (vlc_object_t *);
  49 static void Close (vlc_object_t *);
  50 static int vlc_sd_probe_Open (vlc_object_t *);
  51
  52 /*
  53  * Module descriptor
  54  */
  55 vlc_module_begin ()
  56     set_shortname (N_("Video capture"))
  57     set_description (N_("Video capture (Video4Linux)"))
  58     set_category (CAT_PLAYLIST)
  59     set_subcategory (SUBCAT_PLAYLIST_SD)
  60     set_capability ("services_discovery", 0)
  61     set_callbacks (OpenV4L, Close)
  62     add_shortcut ("v4l", "video")
  63 #ifdef HAVE_ALSA
  64     add_submodule ()
  65     set_shortname (N_("Audio capture"))
  66     set_description (N_("Audio capture (ALSA)"))
  67     set_category (CAT_PLAYLIST)
  68     set_subcategory (SUBCAT_PLAYLIST_SD)
  69     set_capability ("services_discovery", 0)
  70     set_callbacks (OpenALSA, Close)
  71     add_shortcut ("alsa", "audio")
  72 #endif
  73     add_submodule ()
  74     set_shortname (N_("Discs"))
  75     set_description (N_("Discs"))
  76     set_category (CAT_PLAYLIST)
  77     set_subcategory (SUBCAT_PLAYLIST_SD)
  78     set_capability ("services_discovery", 0)
  79     set_callbacks (OpenDisc, Close)
  80     add_shortcut ("disc")
  81
  82     VLC_SD_PROBE_SUBMODULE
  83
  84 vlc_module_end ()
  85
  86 static int vlc_sd_probe_Open (vlc_object_t *obj)
  87 {
  88     vlc_probe_t *probe = (vlc_probe_t *)obj;
  89
  90     struct udev *udev = udev_new ();
  91     if (udev == NULL)
  92         return VLC_PROBE_CONTINUE;
  93
  94     struct udev_monitor *mon = udev_monitor_new_from_netlink (udev, "udev");
  95     if (mon != NULL)
  96     {
  97         vlc_sd_probe_Add (probe, "v4l", N_("Video capture"), SD_CAT_DEVICES);
  98 #ifdef HAVE_ALSA
  99         if (!module_exists ("pulselist"))
 100             vlc_sd_probe_Add (probe, "alsa", N_("Audio capture"),
 101                               SD_CAT_DEVICES);
 102 #endif
 103         vlc_sd_probe_Add (probe, "disc", N_("Discs"), SD_CAT_DEVICES);
 104         udev_monitor_unref (mon);
 105     }
 106     udev_unref (udev);
 107     return VLC_PROBE_CONTINUE;
 108 }
 109
 110 struct device
 111 {
 112     dev_t devnum; /* must be first */
 113     input_item_t *item;
 114     services_discovery_t *sd;
 115 };
 116
 117 struct subsys
 118 {
 119     const char *name;
 120     const char *description;
 121     char * (*get_mrl) (struct udev_device *dev);
 122     char * (*get_name) (struct udev_device *dev);
 123     int item_type;
 124 };
 125
 126 typedef struct
 127 {
 128     const struct subsys *subsys;
 129     struct udev_monitor *monitor;
 130     vlc_thread_t         thread;
 131     void                *root;
 132 } services_discovery_sys_t;
 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     input_item_Release (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_NewExt (mrl, name ? name : mrl,
 172                                             INPUT_DURATION_INDEFINITE,
 173                                             p_sys->subsys->item_type, ITEM_LOCAL);
 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         input_item_Release (item);
 184         return -1;
 185     }
 186     d->devnum = udev_device_get_devnum (dev);
 187     d->item = item;
 188     d->sd = NULL;
 189
 190     void **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);
 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     void **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
 237     sd->description = vlc_gettext(subsys->description);
 238     sd->p_sys = p_sys;
 239     p_sys->subsys = subsys;
 240     p_sys->root = NULL;
 241
 242     struct udev_monitor *mon = NULL;
 243     struct udev *udev = udev_new ();
 244     if (udev == NULL)
 245         goto error;
 246
 247     mon = udev_monitor_new_from_netlink (udev, "udev");
 248     if (mon == NULL
 249      || udev_monitor_filter_add_match_subsystem_devtype (mon, subsys->name,
 250                                                          NULL))
 251         goto error;
 252     p_sys->monitor = mon;
 253
 254     /* Enumerate existing devices */
 255     struct udev_enumerate *devenum = udev_enumerate_new (udev);
 256     if (devenum == NULL)
 257         goto error;
 258     if (udev_enumerate_add_match_subsystem (devenum, subsys->name))
 259     {
 260         udev_enumerate_unref (devenum);
 261         goto error;
 262     }
 263
 264     udev_monitor_enable_receiving (mon);
 265     /* Note that we enumerate _after_ monitoring is enabled so that we do not
 266      * loose device events occuring while we are enumerating. We could still
 267      * loose events if the Netlink socket receive buffer overflows. */
 268     udev_enumerate_scan_devices (devenum);
 269     struct udev_list_entry *devlist = udev_enumerate_get_list_entry (devenum);
 270     struct udev_list_entry *deventry;
 271     udev_list_entry_foreach (deventry, devlist)
 272     {
 273         const char *path = udev_list_entry_get_name (deventry);
 274         struct udev_device *dev = udev_device_new_from_syspath (udev, path);
 275         AddDevice (sd, dev);
 276         udev_device_unref (dev);
 277     }
 278     udev_enumerate_unref (devenum);
 279
 280     if (vlc_clone (&p_sys->thread, Run, sd, VLC_THREAD_PRIORITY_LOW))
 281     {   /* Fallback without thread */
 282         udev_monitor_unref (mon);
 283         udev_unref (udev);
 284         p_sys->monitor = NULL;
 285     }
 286     return VLC_SUCCESS;
 287
 288 error:
 289     if (mon != NULL)
 290         udev_monitor_unref (mon);
 291     if (udev != NULL)
 292         udev_unref (udev);
 293     free (p_sys);
 294     return VLC_EGENERIC;
 295 }
 296
 297 /**
 298  * Releases resources
 299  */
 300 static void Close (vlc_object_t *obj)
 301 {
 302     services_discovery_t *sd = (services_discovery_t *)obj;
 303     services_discovery_sys_t *p_sys = sd->p_sys;
 304
 305     if (p_sys->monitor != NULL)
 306     {
 307         struct udev *udev = udev_monitor_get_udev (p_sys->monitor);
 308
 309         vlc_cancel (p_sys->thread);
 310         vlc_join (p_sys->thread, NULL);
 311         udev_monitor_unref (p_sys->monitor);
 312         udev_unref (udev);
 313     }
 314
 315     tdestroy (p_sys->root, DestroyDevice);
 316     free (p_sys);
 317 }
 318
 319 static void *Run (void *data)
 320 {
 321     services_discovery_t *sd = data;
 322     services_discovery_sys_t *p_sys = sd->p_sys;
 323     struct udev_monitor *mon = p_sys->monitor;
 324
 325     int fd = udev_monitor_get_fd (mon);
 326     struct pollfd ufd = { .fd = fd, .events = POLLIN, };
 327
 328     for (;;)
 329     {
 330         while (poll (&ufd, 1, -1) == -1)
 331             if (errno != EINTR)
 332                 break;
 333
 334         int canc = vlc_savecancel ();
 335         struct udev_device *dev = udev_monitor_receive_device (mon);
 336         if (dev == NULL)
 337             continue;
 338
 339         const char *action = udev_device_get_action (dev);
 340         if (!strcmp (action, "add"))
 341             AddDevice (sd, dev);
 342         else if (!strcmp (action, "remove"))
 343             RemoveDevice (sd, dev);
 344         else if (!strcmp (action, "change"))
 345         {
 346             RemoveDevice (sd, dev);
 347             AddDevice (sd, dev);
 348         }
 349         udev_device_unref (dev);
 350         vlc_restorecancel (canc);
 351     }
 352     return NULL;
 353 }
 354
 355 /**
 356  * Converts an hexadecimal digit to an integer.
 357  */
 358 static int hex (char c)
 359 {
 360     if (c >= '0' && c <= '9')
 361         return c - '0';
 362     if (c >= 'A' && c <= 'F')
 363         return c + 10 - 'A';
 364     if (c >= 'a' && c <= 'f')
 365         return c + 10 - 'a';
 366     return -1;
 367 }
 368
 369 /**
 370  * Decodes a udev hexadecimal-encoded property.
 371  */
 372 static char *decode (const char *enc)
 373 {
 374     char *ret = enc ? strdup (enc) : NULL;
 375     if (ret == NULL)
 376         return NULL;
 377
 378     char *out = ret;
 379     for (const char *in = ret; *in; out++)
 380     {
 381         int h1, h2;
 382
 383         if ((in[0] == '\\') && (in[1] == 'x')
 384          && ((h1 = hex (in[2])) != -1)
 385          && ((h2 = hex (in[3])) != -1))
 386         {
 387             *out = (h1 << 4) | h2;
 388             in += 4;
 389         }
 390         else
 391         {
 392             *out = *in;
 393             in++;
 394         }
 395     }
 396     *out = 0;
 397     return ret;
 398 }
 399
 400 static char *decode_property (struct udev_device *dev, const char *name)
 401 {
 402     return decode (udev_device_get_property_value (dev, name));
 403 }
 404
 405
 406 /*** Video4Linux support ***/
 407 static bool v4l_is_legacy (struct udev_device *dev)
 408 {
 409     const char *version;
 410
 411     version = udev_device_get_property_value (dev, "ID_V4L_VERSION");
 412     return (version != NULL) && !strcmp (version, "1");
 413 }
 414
 415 static bool v4l_can_capture (struct udev_device *dev)
 416 {
 417     const char *caps;
 418
 419     caps = udev_device_get_property_value (dev, "ID_V4L_CAPABILITIES");
 420     return (caps != NULL) && (strstr (caps, ":capture:") != NULL);
 421 }
 422
 423 static char *v4l_get_mrl (struct udev_device *dev)
 424 {
 425     /* Determine media location */
 426     if (v4l_is_legacy (dev) || !v4l_can_capture (dev))
 427         return NULL;
 428
 429     const char *node = udev_device_get_devnode (dev);
 430     char *mrl;
 431
 432     if (asprintf (&mrl, "v4l2://%s", node) == -1)
 433         mrl = NULL;
 434     return mrl;
 435 }
 436
 437 static char *v4l_get_name (struct udev_device *dev)
 438 {
 439     const char *prd = udev_device_get_property_value (dev, "ID_V4L_PRODUCT");
 440     return prd ? strdup (prd) : NULL;
 441 }
 442
 443 int OpenV4L (vlc_object_t *obj)
 444 {
 445     static const struct subsys subsys = {
 446         "video4linux", N_("Video capture"),
 447         v4l_get_mrl, v4l_get_name, ITEM_TYPE_CARD,
 448     };
 449
 450     return Open (obj, &subsys);
 451 }
 452
 453
 454 #ifdef HAVE_ALSA
 455 /*** Advanced Linux Sound Architecture support ***/
 456 #include <alsa/asoundlib.h>
 457
 458 static int alsa_get_device (struct udev_device *dev, unsigned *restrict pcard,
 459                             unsigned *restrict pdevice)
 460 {
 461     const char *node = udev_device_get_devpath (dev);
 462     char type;
 463
 464     node = strrchr (node, '/');
 465     if (node == NULL)
 466         return -1;
 467     if (sscanf (node, "/pcmC%uD%u%c", pcard, pdevice, &type) < 3)
 468         return -1;
 469     if (type != 'c')
 470         return -1;
 471     return 0;
 472 }
 473
 474
 475 static char *alsa_get_mrl (struct udev_device *dev)
 476 {
 477     /* Determine media location */
 478     char *mrl;
 479     unsigned card, device;
 480
 481     if (alsa_get_device (dev, &card, &device))
 482         return NULL;
 483
 484     if (asprintf (&mrl, "alsa://plughw:%u,%u", card, device) == -1)
 485         mrl = NULL;
 486     return mrl;
 487 }
 488
 489 static char *alsa_get_name (struct udev_device *dev)
 490 {
 491     char *name = NULL;
 492     unsigned card, device;
 493
 494     if (alsa_get_device (dev, &card, &device))
 495         return NULL;
 496
 497     char card_name[4 + 3 * sizeof (int)];
 498     snprintf (card_name, sizeof (card_name), "hw:%u", card);
 499
 500     snd_ctl_t *ctl;
 501     if (snd_ctl_open (&ctl, card_name, 0))
 502         return NULL;
 503
 504     snd_pcm_info_t *pcm_info;
 505     snd_pcm_info_alloca (&pcm_info);
 506     snd_pcm_info_set_device (pcm_info, device);
 507     snd_pcm_info_set_subdevice (pcm_info, 0);
 508     snd_pcm_info_set_stream (pcm_info, SND_PCM_STREAM_CAPTURE);
 509     if (snd_ctl_pcm_info (ctl, pcm_info))
 510         goto out;
 511
 512     name = strdup (snd_pcm_info_get_name (pcm_info));
 513 out:
 514     snd_ctl_close (ctl);
 515     return name;
 516 }
 517
 518 int OpenALSA (vlc_object_t *obj)
 519 {
 520     static const struct subsys subsys = {
 521         "sound", N_("Audio capture"),
 522         alsa_get_mrl, alsa_get_name, ITEM_TYPE_CARD,
 523     };
 524
 525     return Open (obj, &subsys);
 526 }
 527 #endif /* HAVE_ALSA */
 528
 529
 530 /*** Discs support ***/
 531 static char *disc_get_mrl (struct udev_device *dev)
 532 {
 533     const char *node = udev_device_get_devnode (dev);
 534     const char *val;
 535
 536     val = udev_device_get_property_value (dev, "ID_CDROM");
 537     if (val == NULL)
 538         return NULL; /* Ignore non-optical block devices */
 539
 540     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_STATE");
 541     if (val == NULL)
 542     {   /* Force probing of the disc in the drive if any. */
 543         int fd = vlc_open (node, O_RDONLY);
 544         if (fd != -1)
 545             vlc_close (fd);
 546         return NULL;
 547     }
 548     if (!strcmp (val, "blank"))
 549         return NULL; /* ignore empty drives and virgin recordable discs */
 550
 551     const char *scheme = NULL;
 552     val = udev_device_get_property_value (dev,
 553                                           "ID_CDROM_MEDIA_TRACK_COUNT_AUDIO");
 554     if (val && atoi (val))
 555         scheme = "cdda"; /* Audio CD rather than file system */
 556     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_DVD");
 557     if (val && atoi (val))
 558         scheme = "dvd";
 559
 560     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_BD");
 561     if (val && atoi (val))
 562         scheme = "bluray";
 563 #ifdef LOL
 564     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_HDDVD");
 565     if (val && atoi (val))
 566         scheme = "hddvd";
 567 #endif
 568
 569     /* We didn't get any property that could tell we have optical disc
 570        that we can play */
 571     if (scheme == NULL)
 572         return NULL;
 573
 574     return vlc_path2uri (node, scheme);
 575 }
 576
 577 static char *disc_get_name (struct udev_device *dev)
 578 {
 579     char *name = NULL;
 580     struct udev_list_entry *list, *entry;
 581
 582     list = udev_device_get_properties_list_entry (dev);
 583     if (unlikely(list == NULL))
 584         return NULL;
 585
 586     const char *cat = NULL;
 587     udev_list_entry_foreach (entry, list)
 588     {
 589         const char *propname = udev_list_entry_get_name(entry);
 590
 591         if (strncmp(propname, "ID_CDROM_MEDIA_", 15))
 592             continue;
 593         if (!atoi (udev_list_entry_get_value (entry)))
 594             continue;
 595         propname += 15;
 596
 597         if (!strncmp(propname, "CD", 2))
 598             cat = N_("CD");
 599         else if (!strncmp(propname, "DVD", 3))
 600             cat = N_("DVD");
 601         else if (!strncmp(propname, "BD", 2))
 602             cat = N_("Blu-ray");
 603         else if (!strncmp(propname, "HDDVD", 5))
 604             cat = N_("HD DVD");
 605
 606         if (cat != NULL)
 607             break;
 608     }
 609
 610     if (cat == NULL)
 611         cat = N_("Unknown type");
 612
 613     char *label = decode_property (dev, "ID_FS_LABEL_ENC");
 614
 615     if (label)
 616         if (asprintf(&name, "%s (%s)", label, vlc_gettext(cat)) < 0)
 617             name = NULL;
 618     free(label);
 619
 620     return name;
 621 }
 622
 623 int OpenDisc (vlc_object_t *obj)
 624 {
 625     static const struct subsys subsys = {
 626         "block", N_("Discs"), disc_get_mrl, disc_get_name, ITEM_TYPE_DISC,
 627     };
 628
 629     return Open (obj, &subsys);
 630 }