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 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     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, -1,
 172                                             p_sys->subsys->item_type, ITEM_LOCAL);
 173     msg_Dbg (sd, "adding %s (%s)", mrl, name);
 174     free (name);
 175     free (mrl);
 176     if (item == NULL)
 177         return -1;
 178
 179     struct device *d = malloc (sizeof (*d));
 180     if (d == NULL)
 181     {
 182         input_item_Release (item);
 183         return -1;
 184     }
 185     d->devnum = udev_device_get_devnum (dev);
 186     d->item = item;
 187     d->sd = NULL;
 188
 189     struct device **dp = tsearch (d, &p_sys->root, cmpdev);
 190     if (dp == NULL) /* Out-of-memory */
 191     {
 192         DestroyDevice (d);
 193         return -1;
 194     }
 195     if (*dp != d) /* Overwrite existing device */
 196     {
 197         DestroyDevice (*dp);
 198         *dp = d;
 199     }
 200
 201     services_discovery_AddItem(sd, item);
 202     d->sd = sd;
 203     return 0;
 204 }
 205
 206 /**
 207  * Removes a udev device (if present).
 208  */
 209 static void RemoveDevice (services_discovery_t *sd, struct udev_device *dev)
 210 {
 211     services_discovery_sys_t *p_sys = sd->p_sys;
 212
 213     dev_t num = udev_device_get_devnum (dev);
 214     struct device **dp = tfind (&(dev_t){ num }, &p_sys->root, cmpdev);
 215     if (dp == NULL)
 216         return;
 217
 218     struct device *d = *dp;
 219     tdelete (d, &p_sys->root, cmpdev);
 220     DestroyDevice (d);
 221 }
 222
 223 static void *Run (void *);
 224
 225 /**
 226  * Probes and initializes.
 227  */
 228 static int Open (vlc_object_t *obj, const struct subsys *subsys)
 229 {
 230     services_discovery_t *sd = (services_discovery_t *)obj;
 231     services_discovery_sys_t *p_sys = malloc (sizeof (*p_sys));
 232
 233     if (p_sys == NULL)
 234         return VLC_ENOMEM;
 235
 236     sd->description = vlc_gettext(subsys->description);
 237     sd->p_sys = p_sys;
 238     p_sys->subsys = subsys;
 239     p_sys->root = NULL;
 240
 241     struct udev_monitor *mon = NULL;
 242     struct udev *udev = udev_new ();
 243     if (udev == NULL)
 244         goto error;
 245
 246     mon = udev_monitor_new_from_netlink (udev, "udev");
 247     if (mon == NULL
 248      || udev_monitor_filter_add_match_subsystem_devtype (mon, subsys->name,
 249                                                          NULL))
 250         goto error;
 251     p_sys->monitor = mon;
 252
 253     /* Enumerate existing devices */
 254     struct udev_enumerate *devenum = udev_enumerate_new (udev);
 255     if (devenum == NULL)
 256         goto error;
 257     if (udev_enumerate_add_match_subsystem (devenum, subsys->name))
 258     {
 259         udev_enumerate_unref (devenum);
 260         goto error;
 261     }
 262
 263     udev_monitor_enable_receiving (mon);
 264     /* Note that we enumerate _after_ monitoring is enabled so that we do not
 265      * loose device events occuring while we are enumerating. We could still
 266      * loose events if the Netlink socket receive buffer overflows. */
 267     udev_enumerate_scan_devices (devenum);
 268     struct udev_list_entry *devlist = udev_enumerate_get_list_entry (devenum);
 269     struct udev_list_entry *deventry;
 270     udev_list_entry_foreach (deventry, devlist)
 271     {
 272         const char *path = udev_list_entry_get_name (deventry);
 273         struct udev_device *dev = udev_device_new_from_syspath (udev, path);
 274         AddDevice (sd, dev);
 275         udev_device_unref (dev);
 276     }
 277     udev_enumerate_unref (devenum);
 278
 279     if (vlc_clone (&p_sys->thread, Run, sd, VLC_THREAD_PRIORITY_LOW))
 280     {   /* Fallback without thread */
 281         udev_monitor_unref (mon);
 282         udev_unref (udev);
 283         p_sys->monitor = NULL;
 284     }
 285     return VLC_SUCCESS;
 286
 287 error:
 288     if (mon != NULL)
 289         udev_monitor_unref (mon);
 290     if (udev != NULL)
 291         udev_unref (udev);
 292     free (p_sys);
 293     return VLC_EGENERIC;
 294 }
 295
 296 /**
 297  * Releases resources
 298  */
 299 static void Close (vlc_object_t *obj)
 300 {
 301     services_discovery_t *sd = (services_discovery_t *)obj;
 302     services_discovery_sys_t *p_sys = sd->p_sys;
 303
 304     if (p_sys->monitor != NULL)
 305     {
 306         struct udev *udev = udev_monitor_get_udev (p_sys->monitor);
 307
 308         vlc_cancel (p_sys->thread);
 309         vlc_join (p_sys->thread, NULL);
 310         udev_monitor_unref (p_sys->monitor);
 311         udev_unref (udev);
 312     }
 313
 314     tdestroy (p_sys->root, DestroyDevice);
 315     free (p_sys);
 316 }
 317
 318 static void *Run (void *data)
 319 {
 320     services_discovery_t *sd = data;
 321     services_discovery_sys_t *p_sys = sd->p_sys;
 322     struct udev_monitor *mon = p_sys->monitor;
 323
 324     int fd = udev_monitor_get_fd (mon);
 325     struct pollfd ufd = { .fd = fd, .events = POLLIN, };
 326
 327     for (;;)
 328     {
 329         while (poll (&ufd, 1, -1) == -1)
 330             if (errno != EINTR)
 331                 break;
 332
 333         int canc = vlc_savecancel ();
 334         struct udev_device *dev = udev_monitor_receive_device (mon);
 335         if (dev == NULL)
 336             continue;
 337
 338         const char *action = udev_device_get_action (dev);
 339         if (!strcmp (action, "add"))
 340             AddDevice (sd, dev);
 341         else if (!strcmp (action, "remove"))
 342             RemoveDevice (sd, dev);
 343         else if (!strcmp (action, "change"))
 344         {
 345             RemoveDevice (sd, dev);
 346             AddDevice (sd, dev);
 347         }
 348         udev_device_unref (dev);
 349         vlc_restorecancel (canc);
 350     }
 351     return NULL;
 352 }
 353
 354 /**
 355  * Converts an hexadecimal digit to an integer.
 356  */
 357 static int hex (char c)
 358 {
 359     if (c >= '0' && c <= '9')
 360         return c - '0';
 361     if (c >= 'A' && c <= 'F')
 362         return c + 10 - 'A';
 363     if (c >= 'a' && c <= 'f')
 364         return c + 10 - 'a';
 365     return -1;
 366 }
 367
 368 /**
 369  * Decodes a udev hexadecimal-encoded property.
 370  */
 371 static char *decode (const char *enc)
 372 {
 373     char *ret = enc ? strdup (enc) : NULL;
 374     if (ret == NULL)
 375         return NULL;
 376
 377     char *out = ret;
 378     for (const char *in = ret; *in; out++)
 379     {
 380         int h1, h2;
 381
 382         if ((in[0] == '\\') && (in[1] == 'x')
 383          && ((h1 = hex (in[2])) != -1)
 384          && ((h2 = hex (in[3])) != -1))
 385         {
 386             *out = (h1 << 4) | h2;
 387             in += 4;
 388         }
 389         else
 390         {
 391             *out = *in;
 392             in++;
 393         }
 394     }
 395     *out = 0;
 396     return ret;
 397 }
 398
 399 static char *decode_property (struct udev_device *dev, const char *name)
 400 {
 401     return decode (udev_device_get_property_value (dev, name));
 402 }
 403
 404
 405 /*** Video4Linux support ***/
 406 static bool v4l_is_legacy (struct udev_device *dev)
 407 {
 408     const char *version;
 409
 410     version = udev_device_get_property_value (dev, "ID_V4L_VERSION");
 411     return (version != NULL) && !strcmp (version, "1");
 412 }
 413
 414 static bool v4l_can_capture (struct udev_device *dev)
 415 {
 416     const char *caps;
 417
 418     caps = udev_device_get_property_value (dev, "ID_V4L_CAPABILITIES");
 419     return (caps != NULL) && (strstr (caps, ":capture:") != NULL);
 420 }
 421
 422 static char *v4l_get_mrl (struct udev_device *dev)
 423 {
 424     /* Determine media location */
 425     if (v4l_is_legacy (dev) || !v4l_can_capture (dev))
 426         return NULL;
 427
 428     const char *node = udev_device_get_devnode (dev);
 429     char *mrl;
 430
 431     if (asprintf (&mrl, "v4l2://%s", node) == -1)
 432         mrl = NULL;
 433     return mrl;
 434 }
 435
 436 static char *v4l_get_name (struct udev_device *dev)
 437 {
 438     const char *prd = udev_device_get_property_value (dev, "ID_V4L_PRODUCT");
 439     return prd ? strdup (prd) : NULL;
 440 }
 441
 442 int OpenV4L (vlc_object_t *obj)
 443 {
 444     static const struct subsys subsys = {
 445         "video4linux", N_("Video capture"),
 446         v4l_get_mrl, v4l_get_name, ITEM_TYPE_CARD,
 447     };
 448
 449     return Open (obj, &subsys);
 450 }
 451
 452
 453 #ifdef HAVE_ALSA
 454 /*** Advanced Linux Sound Architecture support ***/
 455 #include <alsa/asoundlib.h>
 456
 457 static int alsa_get_device (struct udev_device *dev, unsigned *restrict pcard,
 458                             unsigned *restrict pdevice)
 459 {
 460     const char *node = udev_device_get_devpath (dev);
 461     char type;
 462
 463     node = strrchr (node, '/');
 464     if (node == NULL)
 465         return -1;
 466     if (sscanf (node, "/pcmC%uD%u%c", pcard, pdevice, &type) < 3)
 467         return -1;
 468     if (type != 'c')
 469         return -1;
 470     return 0;
 471 }
 472
 473
 474 static char *alsa_get_mrl (struct udev_device *dev)
 475 {
 476     /* Determine media location */
 477     char *mrl;
 478     unsigned card, device;
 479
 480     if (alsa_get_device (dev, &card, &device))
 481         return NULL;
 482
 483     if (asprintf (&mrl, "alsa://plughw:%u,%u", card, device) == -1)
 484         mrl = NULL;
 485     return mrl;
 486 }
 487
 488 static char *alsa_get_name (struct udev_device *dev)
 489 {
 490     char *name = NULL;
 491     unsigned card, device;
 492
 493     if (alsa_get_device (dev, &card, &device))
 494         return NULL;
 495
 496     char card_name[4 + 3 * sizeof (int)];
 497     snprintf (card_name, sizeof (card_name), "hw:%u", card);
 498
 499     snd_ctl_t *ctl;
 500     if (snd_ctl_open (&ctl, card_name, 0))
 501         return NULL;
 502
 503     snd_pcm_info_t *pcm_info;
 504     snd_pcm_info_alloca (&pcm_info);
 505     snd_pcm_info_set_device (pcm_info, device);
 506     snd_pcm_info_set_subdevice (pcm_info, 0);
 507     snd_pcm_info_set_stream (pcm_info, SND_PCM_STREAM_CAPTURE);
 508     if (snd_ctl_pcm_info (ctl, pcm_info))
 509         goto out;
 510
 511     name = strdup (snd_pcm_info_get_name (pcm_info));
 512 out:
 513     snd_ctl_close (ctl);
 514     return name;
 515 }
 516
 517 int OpenALSA (vlc_object_t *obj)
 518 {
 519     static const struct subsys subsys = {
 520         "sound", N_("Audio capture"),
 521         alsa_get_mrl, alsa_get_name, ITEM_TYPE_CARD,
 522     };
 523
 524     return Open (obj, &subsys);
 525 }
 526 #endif /* HAVE_ALSA */
 527
 528
 529 /*** Discs support ***/
 530 static char *disc_get_mrl (struct udev_device *dev)
 531 {
 532     const char *node = udev_device_get_devnode (dev);
 533     const char *val;
 534
 535     val = udev_device_get_property_value (dev, "ID_CDROM");
 536     if (val == NULL)
 537         return NULL; /* Ignore non-optical block devices */
 538
 539     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_STATE");
 540     if (val == NULL)
 541     {   /* Force probing of the disc in the drive if any. */
 542         int fd = vlc_open (node, O_RDONLY);
 543         if (fd != -1)
 544             vlc_close (fd);
 545         return NULL;
 546     }
 547     if (!strcmp (val, "blank"))
 548         return NULL; /* ignore empty drives and virgin recordable discs */
 549
 550     const char *scheme = NULL;
 551     val = udev_device_get_property_value (dev,
 552                                           "ID_CDROM_MEDIA_TRACK_COUNT_AUDIO");
 553     if (val && atoi (val))
 554         scheme = "cdda"; /* Audio CD rather than file system */
 555     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_DVD");
 556     if (val && atoi (val))
 557         scheme = "dvd";
 558
 559     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_BD");
 560     if (val && atoi (val))
 561         scheme = "bluray";
 562 #ifdef LOL
 563     val = udev_device_get_property_value (dev, "ID_CDROM_MEDIA_HDDVD");
 564     if (val && atoi (val))
 565         scheme = "hddvd";
 566 #endif
 567
 568     /* We didn't get any property that could tell we have optical disc
 569        that we can play */
 570     if (scheme == NULL)
 571         return NULL;
 572
 573     return vlc_path2uri (node, scheme);
 574 }
 575
 576 static char *disc_get_name (struct udev_device *dev)
 577 {
 578     char *name = NULL;
 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 *propname = udev_list_entry_get_name(entry);
 589
 590         if (strncmp(propname, "ID_CDROM_MEDIA_", 15))
 591             continue;
 592         if (!atoi (udev_list_entry_get_value (entry)))
 593             continue;
 594         propname += 15;
 595
 596         if (!strncmp(propname, "CD", 2))
 597             cat = N_("CD");
 598         else if (!strncmp(propname, "DVD", 3))
 599             cat = N_("DVD");
 600         else if (!strncmp(propname, "BD", 2))
 601             cat = N_("Blu-ray");
 602         else if (!strncmp(propname, "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
 612     char *label = decode_property (dev, "ID_FS_LABEL_ENC");
 613
 614     if (label)
 615         if (asprintf(&name, "%s (%s)", label, vlc_gettext(cat)) < 0)
 616             name = NULL;
 617     free(label);
 618
 619     return name;
 620 }
 621
 622 int OpenDisc (vlc_object_t *obj)
 623 {
 624     static const struct subsys subsys = {
 625         "block", N_("Discs"), disc_get_mrl, disc_get_name, ITEM_TYPE_DISC,
 626     };
 627
 628     return Open (obj, &subsys);
 629 }